Sacituzumab govitecan in metastatic triple-negative breast cancer patients treated at Institut Curie Hospitals: efficacy, safety, and impact of brain metastases

BACKGROUND

Sacituzumab govitecan (SG) has been approved by FDA in April 2021 for pre-treated metastatic triple-negative breast cancer (mTNBC), following the ASCENT trial results.

METHODS

We set up an ambispective bicentric cohort study to assess the real-world effectiveness and safety of SG in patients with mTNBC treated at Institut Curie Hospitals, with a focus on patients with brain metastases.

RESULTS

This study included 99 patients treated through the French Early Access Program to SG from May 2021 to January 2023. Median age was 55 years [26-89], N = 8 patients (8%) had BRCA1/2 mutation, N = 12 (12%) de novo stage IV disease and N = 31 (31%) brain metastases. Patients had previously received a median of two [1-10] lines of treatment in advanced setting. After a median follow-up of 9.7 months, the median progression-free survival (PFS) and overall survival (OS) were 3.9 months (95%CI[3.4-5.0]) and 8.6 months (95%CI[7.1-11.9]), respectively, while objective response rate was 29% (95%CI[21-39]). Among patients with brain metastases, median PFS and OS were 3.7 months (95%CI[2.6-6.2]) and 6.7 months (95%CI[6.3-NR]), respectively, with intracranial tumor responses. Dose reductions were required in N = 17 patients (17%) within a median of three [2-11] cycles, due to gastrointestinal toxicity (N = 6; 6%), hematological toxicity (N = 9; 9%) including febrile neutropenia (N = 2; 2%), liver enzyme elevation (N = 1; 1%), and physical deterioration (N = 1; 1%). There was no related death to SG.

CONCLUSIONS

The observed response rate and safety of SG are consistent with the results of the ASCENT trial, with efficacy observed in patients with brain metastases, but observed PFS and OS are numerically shorter.

Study design for DESTINY-Breast Respond HER2-low Europe: T-DXd in patients with HER2-low advanced breast cancer

Trastuzumab deruxtecan (T-DXd) is approved for the treatment of human epidermal growth factor receptor 2 (HER2)-low metastatic breast cancer (mBC). Results on T-DXd treatment in HER2-low mBC have so far been limited to clinical trials. DESTINY-Breast Respond HER2-low Europe (NCT05945732) is a multi-center, multi-country, observational, prospective, non-interventional study planning to enroll 1350 patients from 216 sites receiving T-DXd or conventional chemotherapy as their routine clinical care for advanced stage breast cancer in 12 European countries. This non-interventional study will provide real-world insight into T-DXd treatment for HER2-low mBC with data on effectiveness, safety and tolerability, patient-reported outcomes, treatment patterns, geriatric health status and HER2 testing. This will be beneficial for improving guidance to maximize patient treatment benefit.

Concomitant medication, comorbidity and survival in patients with breast cancer

Between 30% and 70% of patients with breast cancer have pre-existing chronic conditions, and more than half are on long-term non-cancer medication at the time of diagnosis. Preliminary epidemiological evidence suggests that some non-cancer medications may affect breast cancer risk, recurrence, and survival. In this nationwide cohort study, we assessed the association between medication use at breast cancer diagnosis and survival. We included 235,368 French women with newly diagnosed non-metastatic breast cancer. In analyzes of 288 medications, we identified eight medications positively associated with either overall survival or disease-free survival: rabeprazole, alverine, atenolol, simvastatin, rosuvastatin, estriol (vaginal or transmucosal), nomegestrol, and hypromellose; and eight medications negatively associated with overall survival or disease-free survival: ferrous fumarate, prednisolone, carbimazole, pristinamycin, oxazepam, alprazolam, hydroxyzine, and mianserin. Full results are available online from an interactive platform ( https://adrenaline.curie.fr ). This resource provides hypotheses for drugs that may naturally influence breast cancer evolution.

Tucatinib Combination Treatment After Trastuzumab-Deruxtecan in Patients With ERBB2-Positive Metastatic Breast Cancer

Importance

Little is known regarding the outcomes associated with tucatinib combined with trastuzumab and capecitabine (TTC) after trastuzumab-deruxtecan exposure among patients with ERBB2 (previously HER2)-positive metastatic breast cancer (MBC).

Objective

To investigate outcomes following TTC treatment in patients with ERBB2-positive MBC who had previously received trastuzumab-deruxtecan.

Design, Setting, and Participants

This cohort study included all patients with MBC who were treated in 12 French comprehensive cancer centers between August 1, 2020, and December 31, 2022.

Exposure

Tucatinib combined with trastuzumab and capecitabine administered at the recommended dose.

Main Outcomes and Measures

Clinical end points included progression-free survival (PFS), time to next treatment (TTNT), overall survival (OS), and overall response rate (ORR).

Results

A total of 101 patients with MBC were included (median age, 56 [range, 31-85] years). The median number of prior treatment lines for metastatic disease at TTC treatment initiation was 4 (range, 2-15), including 82 patients (81.2%) with previous trastuzumab and/or pertuzumab and 94 (93.1%) with previous ado-trastuzumab-emtansine) exposure. The median duration of trastuzumab-deruxtecan treatment was 8.9 (range, 1.4-25.8) months, and 82 patients (81.2%) had disease progression during trastuzumab-deruxtecan treatment, whereas 18 (17.8%) had stopped trastuzumab-deruxtecan for toxic effects and 1 (1.0%) for other reasons. Tucatinib combined with trastuzumab and capecitabine was provided as a third- or fourth-line treatment in 37 patients (36.6%) and was the immediate treatment after trastuzumab-deruxtecan in 86 (85.1%). With a median follow-up of 11.6 (95% CI, 10.5-13.4) months, 76 of 101 patients (75.2%) stopped TTC treatment due to disease progression. The median PFS was 4.7 (95% CI, 3.9-5.6) months; median TTNT, 5.2 (95% CI, 4.5-7.0) months; and median OS, 13.4 (95% CI, 11.1 to not reached [NR]) months. Patients who received TTC immediately after trastuzumab-deruxtecan had a median PFS of 5.0 (95% CI, 4.2-6.0) months; median TTNT of 5.5 (95% CI, 4.8-7.2) months, and median OS of 13.4 (95% CI, 11.9-NR) months. Those who received TTC due to trastuzumab-deruxtecan toxicity-related discontinuation had a median PFS of 7.3 (95% CI, 3.0-NR) months. Best ORR was 29 of 89 patients (32.6%). Sixteen patients with active brain metastasis had a median PFS of 4.7 (95% CI, 3.0-7.3) months, median TTNT of 5.6 (95% CI, 4.4 to NR), and median OS of 12.4 (95% CI, 8.3-NR) months.

Conclusions and Relevance

In this study, TTC therapy was associated with clinically meaningful outcomes in patients with ERBB2-positive MBC after previous trastuzumab-deruxtecan treatment, including those with brain metastases. Prospective data on optimal drug sequencing in this rapidly changing therapeutic landscape are needed.

Rethinking surgical revisions: impact of the MonarchE trial on axillary dissection in hormone-positive HER2-negative early breast cancer patients potentially eligible for abemaciclib

INTRODUCTION

The MonarchE trial explored the use of abemaciclib, a CDK4/6 inhibitor, as an adjuvant treatment in high-risk early-stage luminal-like breast cancer. The study's inclusion criteria, especially the N2 status, may require revisiting surgical interventions, including invasive axillary lymph node dissection (ALND)-a procedure that current guidelines generally do not recommend.

METHODS

We conducted a single-centre, retrospective, observational cohort study on non-metastatic breast cancer patients managed from 2002 to 2011, at the Institut Curie. Data collection involved clinical and histological characteristics plus treatment follow-up.

RESULTS

Out of 8715 treated patients, 721 met the inclusion criteria. Overall, 12% (87) were classified as N2 ( ≥ 4 positive lymph nodes), thus eligible for abemaciclib per "node criterion." Tumour size, positive sentinel lymph nodes, and lobular histology showed a significant correlation with N2 status. Approximately 1000 ALNDs would be required to identify 120 N2 cases and prevent four recurrences.

CONCLUSION

The MonarchE trial may significantly affect surgical practices due to the need for invasive procedures to identify high-risk patients for adjuvant abemaciclib treatment. The prospect of unnecessary morbidity demands less invasive N2 status determination methods. Surgical decisions must consider patient health and potential treatment benefits.

Fulvestrant and everolimus efficacy after CDK4/6 inhibitor: a prospective study with circulating tumor DNA analysis

In a prospective study (NCT02866149), we assessed the efficacy of fulvestrant and everolimus in CDK4/6i pre-treated mBC patients and circulating tumor DNA (ctDNA) changes throughout therapy. Patients treated with fulvestrant and everolimus had their ctDNA assessed at baseline, after 3-5 weeks and at disease progression. Somatic mutations were identified in archived tumor tissues by targeted NGS and tracked in cell-free DNA by droplet digital PCR. ctDNA detection was then associated with clinicopathological characteristics and patients' progression-free survival (PFS), overall survival (OS) and best overall response (BOR). In the 57 included patients, median PFS and OS were 6.8 (95%CI [5.03-11.5]) and 38.2 (95%CI [30.0-not reached]) months, respectively. In 47 response-evaluable patients, BOR was a partial response or stable disease in 15 (31.9%) and 11 (23.4%) patients, respectively. Among patients with trackable somatic mutation and available plasma sample, N = 33/47 (70.2%) and N = 19/36 (52.8%) had ctDNA detected at baseline and at 3 weeks, respectively. ctDNA detection at baseline and PIK3CA mutation had an adverse prognostic impact on PFS and OS in multivariate analysis. This prospective cohort study documents the efficacy of fulvestrant and everolimus in CDK4/6i-pretreated ER + /HER2- mBC and highlights the clinical validity of early ctDNA changes as pharmacodynamic biomarker.

Tolerance of Concurrent Adjuvant Radiation Therapy and Pembrolizumab for Triple Negative Breast Cancer: Real Life Experience

Purpose

The current standard-of-care management of locally advanced triple negative breast cancer (TNBC) is based on neoadjuvant chemo-immunotherapy with pembrolizumab, surgery, radiation therapy (RT), and adjuvant pembrolizumab. However, the safety of combining pembrolizumab with adjuvant breast RT has never been evaluated. This study evaluated the tolerance profile of concurrent pembrolizumab with adjuvant RT in patients with locally advanced TNBC.

Methods and Materials

This bicentric ambispective study included all the patients with early and locally advanced TNBC who received neoadjuvant chemo-immunotherapy with pembrolizumab and adjuvant RT as part of their treatment. The tolerance profile of adjuvant RT was evaluated and compared in patients who received concurrent pembrolizumab and in patients for whom pembrolizumab was withheld.

Results

Fifty-five patients were included between July 2021 and March 2023. Twenty-eight patients received adjuvant RT with concurrent pembrolizumab (RT+P group), and 27 patients had pembrolizumab withheld while receiving adjuvant RT (RT-only group). Two patients developed grade ≥3 toxicity (1 grade 3 pain in the RT+P group and 1 grade 3 radiodermatitis in the RT-only group), and there were no differences in terms of toxicity between the RT-only and the RT+P groups. No cardiac or pulmonary adverse event was reported during RT. With a median follow-up of 12 months (10-26), no patient relapsed.

Conclusions

In this study of limited size, the authors did not find a difference between the RT-only and RT+P groups in terms of toxicity. More studies and longer follow-up may add to the strength of this evidence.

[The French National College of Oncology Teachers (CNEC): Missions, organization, and projects]

The National College of Cancerology Teachers (CNEC) was created in September 1986. Its missions are to develop the teaching of oncology, to promote educational actions in the discipline, to participate in the development of teaching content and the definition of curricula and the control of knowledge for the training of medical students and specialists, to develop and validate educational documents relating to the above teaching, to ensure the representation of oncology teaching to of the National University Council (CNU) and administrative authorities, to ensure and coordinate relations with other university disciplines, scientific societies, national, European, and international professional groups, and to contribute to the development of research in the discipline. The current office was elected in September 2022 for three years.

Overall Survival With Circulating Tumor Cell Count-Driven Choice of Therapy in Advanced Breast Cancer: A Randomized Trial

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.In patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer, the STIC CTC trial established that, for choosing between endocrine therapy (ET) or chemotherapy, the use of circulating tumor cell (CTC) count is noninferior to the investigator's choice in terms of progression-free survival. Here, we report overall survival (OS) results, a secondary end point. Patients were randomly assigned in a 1:1 ratio to have their first-line treatment (ET or chemotherapy) determined by investigators or CTC count (chemotherapy if ≥ 5 CTCs/7.5 mL; ET if low CTC count; CellSearch). OS was assessed at the discontinuation of follow-up. After a median follow-up of 4.7 years, 382 deaths (50.6%) had occurred among 755 patients. Median OS was 51.3 months (95% CI, 46.8 to 55.1) in the CTC arm and 45.5 months (95% CI, 40.9 to 51.1) in the standard arm (hazard ratio [HR] for death, 0.85; 95% CI, 0.69 to 1.03; P = .11). Among 189 patients (25.0%) with ET recommended by clinicians and high CTC count, chemotherapy was superior to ET (HR for death, 0.53; 95% CI, 0.36 to 0.78; P = .001). In case of a discordant estimate, OS data demonstrate the clinical utility of CTC count.

Exploring the added value of pretherapeutic MR descriptors in predicting breast cancer pathologic complete response to neoadjuvant chemotherapy

OBJECTIVES

To evaluate the association between pretreatment MRI descriptors and breast cancer (BC) pathological complete response (pCR) to neoadjuvant chemotherapy (NAC).

MATERIALS AND METHODS

Patients with BC treated by NAC with a breast MRI between 2016 and 2020 were included in this retrospective observational single-center study. MR studies were described using the standardized BI-RADS and breast edema score on T2-weighted MRI. Univariable and multivariable logistic regression analyses were performed to assess variables association with pCR according to residual cancer burden. Random forest classifiers were trained to predict pCR on a random split including 70% of the database and were validated on the remaining cases.

RESULTS

Among 129 BC, 59 (46%) achieved pCR after NAC (luminal (n = 7/37, 19%), triple negative (n = 30/55, 55%), HER2 + (n = 22/37, 59%)). Clinical and biological items associated with pCR were BC subtype (p < 0.001), T stage 0/I/II (p = 0.008), higher Ki67 (p = 0.005), and higher tumor-infiltrating lymphocytes levels (p = 0.016). Univariate analysis showed that the following MRI features, oval or round shape (p = 0.047), unifocality (p = 0.026), non-spiculated margins (p = 0.018), no associated non-mass enhancement (p = 0.024), and a lower MRI size (p = 0.031), were significantly associated with pCR. Unifocality and non-spiculated margins remained independently associated with pCR at multivariable analysis. Adding significant MRI features to clinicobiological variables in random forest classifiers significantly increased sensitivity (0.67 versus 0.62), specificity (0.69 versus 0.67), and precision (0.71 versus 0.67) for pCR prediction.

CONCLUSION

Non-spiculated margins and unifocality are independently associated with pCR and can increase models performance to predict BC response to NAC.

CLINICAL RELEVANCE STATEMENT

A multimodal approach integrating pretreatment MRI features with clinicobiological predictors, including tumor-infiltrating lymphocytes, could be employed to develop machine learning models for identifying patients at risk of non-response. This may enable consideration of alternative therapeutic strategies to optimize treatment outcomes.

KEY POINTS

• Unifocality and non-spiculated margins are independently associated with pCR at multivariable logistic regression analysis. • Breast edema score is associated with MR tumor size and TIL expression, not only in TN BC as previously reported, but also in luminal BC. • Adding significant MRI features to clinicobiological variables in machine learning classifiers significantly increased sensitivity, specificity, and precision for pCR prediction.

Recommandations francophones pour la pratique clinique concernant la prise en charge des cancers du sein de Saint-Paul-de-Vence 2022-2023

With more than 60,000 new cases of breast cancer in mainland France in 2023 and 8% of all cancer deaths, breast cancer is the leading cancer in women in terms of incidence and mortality. While the number of new cases has almost doubled in 30 years, the percentage of patients at all stages alive at 5 years (87%) and 10 years (76%) testifies to the major progress made in terms of screening, characterisation and treatment. However, this progress, rapid as it is, needs to be evaluated and integrated into an overall strategy, taking into account the characteristics of the disease (stage and biology), as well as those of the patients being treated. These are the objectives of the St Paul-de-Vence recommendations for clinical practice. We report here the summary of the votes, discussions and conclusions of the Saint-Paul-de-Vence 2022-2023 RPCs.

Treatments During Pregnancy Targeting ERBB2 and Outcomes of Pregnant Individuals and Newborns

Importance

Targeted therapies directed against ERBB2 are the cornerstone of medical treatment for ERBB2-positive breast cancers but are contraindicated during pregnancy.

Objectives

To describe the association of exposure to anti-ERBB2 agents during pregnancy with pregnancy and fetal or newborn outcomes, and to compare the risk and types of adverse outcomes reported more frequently in this context than after exposure to other anticancer agents.

Design, Setting, and Participants

For this case-control study, All reports with a pregnancy-related condition and an antineoplastic agent (Anatomical Therapeutic Chemical classification group L01) registered in the World Health Organization international pharmacovigilance database VigiBase up to June 26, 2022, were extracted. All reports with a pregnancy, an antineoplastic treatment during pregnancy, and a cancer were retained. Reports with anticancer agents prescribed for nononcologic purposes were not included.

Exposure

The exposure group was defined as reports that mention anti-ERBB2 agents compared with exposure to other anticancer agents.

Main Outcome and Measures

The main outcome was the reporting odds ratio (ROR) for maternofetal complications in the group exposed to anti-ERBB2 agents compared with other anticancer agents, as determined using a disproportionality analysis.

Results

A total of 3558 reports (anti-ERBB2 agents, 328; other anticancer agents, 3230) were included in the analysis. In the group exposed to anti-ERBB2 agents, most reports were from the US (159 [48.5%]), the mean (SD) age of participants was 30.8 (10.4) years, and 209 patients (97.7%) were treated for breast cancers. The molecules most frequently involved in cases with anti-ERBB2 agents were trastuzumab (n = 302), pertuzumab (n = 55), trastuzumab-emtansine (n = 20), and lapatinib (n = 18). The outcomes overreported in these cases included oligohydramnios (ROR, 17.68 [95% CI, 12.26-25.52]; P < .001), congenital respiratory tract disorders (ROR, 9.98 [95% CI, 2.88-34.67]; P < .001), and neonatal kidney failure (ROR, 9.15 [95% CI, 4.62-18.12]; P < .001). Sensitivity and multivariable analyses found similar results. Toxic effects were also significantly overreported for trastuzumab-emtansine (cardiovascular malformation: ROR, 4.46 [95% CI, 1.02-19.52]) and lapatinib (intrauterine growth restriction: ROR, 7.68 [95% CI, 3.01-19.59]).

Conclusions and Relevance

In this case-control study of 328 individuals exposed to anti-ERBB2 agents during pregnancy, exposure was associated with a severe specific adverse pregnancy and fetal or newborn outcomes compared with exposure to other anticancer treatments.

[Diagnosis and management of interstitial lung disease induced by antibody-drug conjugates in breast cancer: A French expert opinion paper]

Interstitial lung disease (ILD) has been reported with many cancer drugs including some recent antibody-drug conjugates (ADCs). The mechanisms of ILD induced by many chemotherapy drugs, other drug classes and ADCs used in cancer, including breast cancer, are not clearly elucidated. In the absence of specific clinical or radiological signs, the diagnosis of drug-induced ILD is often a diagnosis of exclusion. When present, the most frequent symptoms are respiratory signs (cough, dyspnea, chest pain) and general signs (fatigue, fever). Any suspicion of ILD should be evaluated by imaging and, if in doubt, the CT scan should be evaluated by a pulmonologist and a radiologist. A network of multidisciplinary experts for proactive early management of ILD is important, including oncologist, radiologist, pulmonologist, infectious disease specialist and nurses. Patient education is essential to report new or exacerbated lung symptoms and prevent high-grade ILD. Study drug is discontinued temporarily or permanently according to ILD severity and type of ADC. For asymptomatic cases (Grade 1), the efficacy of corticosteroids is not clearly established; for higher grades, the benefit/risk balance of long-term corticosteroid therapy should be considered for the dose and treatment duration. Hospitalization and oxygen supplementation are required for severe cases (Grades 3-4). For patient follow-up, the expertise of a pulmonologist is necessary with repeated chest scans, spirometry and DLCO. Preventing ADC-induced ILDs and evolution to high grade rests on a network of multidisciplinary experts for assessment of individual risk factors, early management, close follow-up and patient education.

Atezolizumab and paclitaxel as first line therapy in advanced triple-negative breast cancer patients included in the French early access program

Following the results of the IMpassion130 trial, an early access program (EAP) was opened in France, allowing patients with PD-L1-positive advanced triple negative breast cancer (aTNBC) to receive a combination of paclitaxel and atezolizumab as first line therapy. This EAP was later discontinued when the IMpassion131 trial read out with negative results. We performed a retrospective multicentric analysis in patients who were prospectively enrolled in the French EAP. Efficacy and toxicity data were obtained on 64 patients treated from August 2019 to August 2020 in 10 French cancer centers. Median progression-free survival (PFS) and overall survival (OS) were 4.1 months (95% CI [3.0-5.8]) and 17.9 months (95% CI [12.4-NR]), respectively. The 6-months PFS rate was 28% (95% CI [16-40%]) (N = 18/64), while N = 33/64 patients (52%, 95% CI [38-63%]) experienced a tumor response. Exploratory subgroup analyses retrieved that corticosteroid use at inclusion in the EAP, before treatment initiation, was the only independent unfavorable prognostic factor for PFS (HR 2.7, 95% CI [1.3-5.6]). No new safety signal was observed. This real-life study, unique by its setting (EAP granted by anticipation and later withdrawn), suggests atezolizumab and paclitaxel has a limited efficacy in PD-L1-positive aTNBC, especially in patients receiving corticosteroids as comedication before treatment start.

Abstract P4-07-24: Circulating tumor cells enumeration and Health Related Quality of Life of patients treated with first-line chemotherapy for HER2 negative metastatic breast cancer

Background: In patients with metastatic breast cancer (mBC), Circulating Tumor Cells (CTC) counts have a strong prognostic impact on progression free survival (PFS) and overall survival (OS). Changes 4 weeks after the start of a new line of therapy, inform on treatment efficacy. Despite improvements in systemic treatment, metastatic BC remains mainly uncurable with alteration of health-related quality of life (HRQOL) during the course of the disease. The aim of this work was to assess impact of clinical factors and biological factors as CTC on HRQOL. Methods: The French cohort COMET is a prospective study including first line HER2 negative patients receiving weekly paclitaxel and bevacizumab according to EMA approved combination. The aim of this cohort was to evaluate clinical, biological and radiological parameters associated with patients’ outcome (CTC, CEC, serum markers, ctDNA, pharmacogenomic polymorphisms, metabolomic parameters, visceral fat assessed by initial CTscan, serum estradiol level, and quality of life). HRQOL was assessed at baseline, at every cycle until progression and then every 3 months up to death using the EORTC QLQ-C30 questionnaire and its breast cancer specific module, the EORTC QLQ-BR23. Five dimensions of HRQOL were analyzed for the primary analyses: Global health status (GHS), physical functioning (PF), Emotional functioning (EF), fatigue (FA) and pain (PA). Time until definitive deterioration (TUDD) in HRQOL was defined as the interval between inclusion and the first decrease in HRQOL score ≥ 5 compared to baseline HRQOL score with no further improvement or in case of death. CTC counts were determined using the standard CellSearch system [Menarini Silicon Biosystems]. Results: Out of 510 patients included in COMET study, 432 patients with available HRQOL data were analyzed in this study. At baseline, patients reported a mean score for GHS of 57.6 (SD=22.7), for PF of 75.8 (23.2), for EF of 62.2 (25.8), for FA of 42.2 (29.60) and for PA of 38.1 (31.5). The Median TUDDs for the 5 targeted dimensions was 10.1 months [7.5-16.9] for GHS, 6.1 months [4.1-8.9] for PF, 21.6 [18.7-31.2] for EF, 10.8 [6.2-16.6] for FA and 13.6[10.1-22.5] months for PA. CTC counts were available in 261 patients at base line and in 229 patients after 4 weeks of treatment, before second cycle of chemotherapy. CTC high count was independent of main clinical and biological characteristics except lobular subtype. We confirmed the poor outcome of patients with high CTC count at base line and after one cycle of treatment with the threshold of &gt; 4CTC/7.5 ml of blood. Out of the 5 dimensions of HRQOL, TUDD of EF was significantly correlated with a high CTC level at base line (p=0.0262) and even more with still an elevated count of CTC after one cycle of chemotherapy(p=0.0137). There was no association of CTC with the other dimensions of HRQOL. Conclusion: This is the first study ever reporting an analysis of QoL and CTC. We observed an association of high CTC count with one component of HRQOL scale. This suggests that CTC could be complementary to clinical factors that could influence HRQOL in HER2 negative metastatic BC treated with first line chemotherapy.

Citation Format: Jean-Yves Pierga, Oumar Billa, Sandrine Dabakuyo, Jérôme Lemonnier, Frédérique Berger, Olivier Trédan, William Jacot, Anthony Gonçalves, Marc Debled, Christelle Levy, Christelle Jouannaud, Marie-Ange Mouret-Reynier, Jean-Marc Ferrero, Florence Dalenc, Fatima-Zohra Toumi, Franck Bonnetain, Francois-Clement Bidard, Shufang Renault. Circulating tumor cells enumeration and Health Related Quality of Life of patients treated with first-line chemotherapy for HER2 negative metastatic breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-24.

Abstract P5-02-19: ctDNA as dynamic marker of response to fulvestrant and everolimus in CDK4/6 inhibitor-pretreated ER+ HER2- metastatic breast cancer patients: a prospective study

ctDNA as dynamic marker of response to fulvestrant and everolimus in CDK4/6 inhibitor-pretreated ER+ HER2- metastatic breast cancer patients: a prospective study. Background The combination of fulvestrant with everolimus is recognized by NCCN and ESMO guidelines as a valid second line treatment option for ER+ HER2- metastatic breast cancer (mBC), upon progression on CDK4/6 inhibitor. The underlying evidence consists in a single randomized phase 2 trial (PrE0102, JCO 2018), in which N=66 patients allocated to fulvestrant and everolimus achieved a median PFS of 10.3 months (95%CI [7.6-13.8]). However, none of PrE0102 patients were pre-treated with CDK4/6 inhibitors. We set up a prospective study to document the PFS achieved by fulvestrant and everolimus in the pre-treated patients and investigated the clinical validity of ctDNA early changes as pharmacodynamic marker. Methods Eligible patients had ER+ HER2- mBC and had to be pre-treated by CDK4/6 inhibitor. Upon the signature of informed consent, patients were enrolled in the prospective observational ALCINA study (NCT02866149) and had their blood drawn at baseline (prior to treatment start), after 1 month on treatment, at first radiological assessment (3-4 months) and at disease progression. DNA from archived tumor tissue sample (or, when missing, from plasma obtained at baseline) was subjected to a large panel next generation sequencing. ctDNA levels were then assessed on the matched serial plasma samples by targeting the identified somatic mutation(s) with droplet digital PCR (ddPCR). Associations between clinicopathological characteristics, ctDNA levels and prospectively registered patient outcomes (PFS and OS) were then analyzed. Results Fifty-seven patients have been included, with a median age of 56.8 years. N=30 (52.6%) patients had ≥3 metastatic sites and N=34 (59.6%) had visceral metastases. Most patients (N=48, 84.2%) had only one prior line of treatment in the metastatic setting. After a median follow-up of 17.7 months, the median PFS was 6.9 months (95%CI[5.3-10.7]) and the median OS was 38.3 months (95%CI[26.9-NA]). The ORR was 33.3% (N=19 PR, no CR) whereas N=22 (38.6%) patients had a stable disease at best response. In the subgroup of N=22 (38.6%) patients with somatic PIK3CA mutations, median PFS was 3.1 months (95%CI[2.87-10.9]), while median OS was not reached. In multivariate analysis, somatic PIK3CA mutation was associated with a trend toward a shorter PFS (HR=1.84, 95%CI[0.97-3.99], p=0.06) and OS (HR=2.23, 95%CI[0.88-5.69], p=0.09). Duration of CDK4/6 inhibitor treatment had no overt impact on PFS (HR=0.68, 95%CI[0.38-1.22], p=0.2). Ten (19.6%) patients discontinued everolimus due to toxicity and 17 (29.9%) had at least one dose reduction due to an adverse event. The most grade 3 adverse event were mucositis (10.5%) and hypertriglyceridemia (3.5%), only 1 patient had a grade 3 pneumopathy. At least one mutation trackable by ddPCR was found in N=48 patients. As of July 2022, ctDNA levels have been analyzed in 34 patients (PIK3CAmut: N=19; ESR1mut: N=6; TP53mut: N=4; AKTmut: N=2; CUX1mut: N=1; GATA3mut: N=1; PTENmut: N=1). At baseline, N= 26/34 patients (76.5%) of patients had detectable ctDNA levels. Baseline ctDNA positivity had no prognostic impact on PFS (HR=0.93, 95%CI[0.4-2.13], p=0.86). ctDNA monitoring in the whole cohort will be available for the congress. Conclusion To our knowledge, this is the first prospective study to evaluate the efficacy of fulvestrant-everolimus after progression on CDK4/6 inhibitor. Efficacy data on 57 patients shows that fulvestrant-everolimus is an active regimen in this population. The PFS observed under fulvestrant-everolimus in patients with PIK3CA-mutant mBC appears shorter than previouly reported with alpelisib in the BYLIEVE study. Results of ctDNA to monitor the individual response to therapy will be presented at the congress.

Citation Format: Antoine Vasseur, Caroline Hego, Wissam Taka, Olfa Trabelsi-Grati, Florence Lerebours, Jean-Yves Pierga, Delphine Loirat, Etienne Brain, Paul COTTU, Marie-Paule Sablin, Luc Cabel, Benjamin Renouf, Shufang Renault, Francois-Clement Bidard. ctDNA as dynamic marker of response to fulvestrant and everolimus in CDK4/6 inhibitor-pretreated ER+ HER2- metastatic breast cancer patients: a prospective study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-02-19.

Abstract PD13-12: PD13-12 Imlunestrant, an oral selective estrogen receptor degrader, in combination with abemaciclib with or without an aromatase inhibitor, in estrogen receptor-positive advanced breast cancer: Results from the phase 1a/b EMBER study

Background: Imlunestrant is a novel, orally bioavailable selective estrogen receptor degrader (SERD) with pure antagonistic properties that result in sustained inhibition of estrogen receptor (ER)-dependent gene transcription and cell growth. Preclinically, imlunestrant has favorable efficacy and pharmacokinetic (PK) properties, including antitumor activity in ESR1-mutant models, along with enhanced efficacy when combined with abemaciclib. In dose escalation (Phase 1a) and dose expansion (Phase 1b) in the EMBER study, imlunestrant monotherapy was well tolerated with favorable safety, PK and encouraging antitumor activity in heavily pre-treated ER+, HER2- advanced breast cancer (aBC) patients (Jhaveri, ASCO 2022); imlunestrant recommended phase 2 dose (RP2D) was determined as 400mg QD. Here, we present the phase 1b dose expansion of imlunestrant with abemaciclib ± aromatase inhibitor (AI) in EMBER (NCT04188548).

Methods: Phase 1b enrolled patients with ER-positive (ER+), HER2-negative (HER2-) aBC [shown prior endocrine therapy (ET) sensitivity or untreated de novo aBC; ≤1 prior therapies for aBC but must not have received a prior CDK4/6 inhibitor]. Patients were randomized, based on menopausal status and presence of visceral metastases, to receive imlunestrant + abemaciclib OR imlunestrant + abemaciclib + AI. Men and premenopausal women received a concomitant GnRH agonist. Serial plasma samples were obtained for PK and ctDNA analysis. Key endpoints included safety and tolerability, PK, objective response rate (ORR) per RECIST v1.1 (ORR: complete response [CR] or partial response [PR]) in patients with measurable disease), and clinical benefit rate (CBR: CR or PR, or stable disease ≥24 weeks) in patients enrolled ≥24 weeks prior to data cut.

Results: As of 26 May 2022, 85 patients have received imlunestrant [n=80 at 400 mg (RP2D); n=5 at 800 mg] in combination with abemaciclib (150mg twice daily) ± AI. Forty-eight (56%) patients had visceral disease and 9% had at least 1 ESR1 mutation detected in ctDNA at baseline. Patients were predominantly (75%) ET pre-treated, 51% with an AI; and 8% and 5%, respectively, had received prior chemotherapy or fulvestrant, for aBC. The most common treatment-emergent adverse events were diarrhea (87%), nausea (58%), fatigue (45%), neutropenia (39%) and abdominal pain (34%). The majority of treatment-related AEs (TRAEs) were Grade 1 or 2, with Grade ≥3 TRAEs occurring in 36% of patients. Most common TRAEs at RP2D (400mg) were diarrhea (81%), nausea (45%), fatigue (33%) and neutropenia (35%). No patient discontinued treatment due to an AE. Dose reductions were required of both imlunestrant and abemaciclib in 6 (7%) patients and of either imlunestrant in 3 (4%) or abemaciclib in 22 (26%) patients. Preliminary efficacy is presented in Table 1.

Conclusion: Imlunestrant in combination with abemaciclib ± AI showed acceptable safety and tolerability, comparable to the MONARCH 2 trial of fulvestrant + abemaciclib, along with evidence of clinical activity in ER+, HER2- aBC patients. These data suggest no additive toxicity of imlunestrant when administered in combination with abemaciclib, along with comparable clinical benefit to that observed in MONARCH 2. Further data will be presented at the meeting. The phase 3, EMBER-3 study is ongoing; evaluating imlunestrant, investigator’s choice ET, and imlunestrant + abemaciclib in ET pre-treated ER+, HER2- aBC patients (NCT04975308).

Table 1. Preliminary efficacy in combination therapies in EMBER

Citation Format: Komal Jhaveri, Hwei-Chung Wang, Cynthia Ma, Elgene Lim, Jessica J. Tao, Luis Manso, Jean-Yves Pierga, Ritesh Parajuli, Yolanda Jerez Gilarranz, Yen-Shen Lu, Muralidhar Beeram, Tim Larson, Ajay Dhakal, Roohi Ismail-Khan, Claudia Karacsonyi, Shanshan Cao, Cynthia Osborne, Shawn T. Estrem, Bastien Nguyen, Yujia Li, Eunice Yuen. PD13-12 Imlunestrant, an oral selective estrogen receptor degrader, in combination with abemaciclib with or without an aromatase inhibitor, in estrogen receptor-positive advanced breast cancer: Results from the phase 1a/b EMBER study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD13-12.

Abstract P3-06-09: Real-world toxicity of pembrolizumab-based neoadjuvant regimen in patients with early triple negative breast cancer

Background Pembrolizumab (pembro, anti-PD-1 antibody) combined to chemotherapy (CT) in neoadjuvant/adjuvant setting has demonstrated its efficacy for early triple negative breast cancer (eTNBC). Pembro obtained FDA marketing authorization on July 26, 2021 and is available in France through the French Early Access Program. Methods We built an ambispective cohort that aimed to evaluate the efficacy and safety of the pembro-CT combination in the real world setting in patients with eTNBC. This study included patients treated from September 2021 to May 2022, at Institut Curie, France. Patients provided written authorization to report their clinical data. We report here the safety results. Results Between September 2021 and May 2022, 51 patients were included. Median age was 49 years [29; 68]. Germline mutations were recorded in 8 patients (22.2% of 36 tested patients). All pts were ECOG PS 0 or 1. Baseline clinical TNM stage were T1 (8 pts, 15.7%), T2 (30 pts, 58.9%), T3 (7 pts, 13.7%) and T4 (6 pts, 11.7%). Out of 37 pts (72.5%) with radiological axillary lymph node involvement, 19 pts (51.4%) had positive node involvement confirmed by guided fine needle aspiration. SBR grade 2 and 3 were observed in 9 (17.6%) and 42 (82.4%) pts, respectively. HER2 score was 0 or 1+/2+(FISH neg) for 31 (60.8 %) and 20 pts (39.2 %), respectively. A CPS score ≥ 10 was observed in 19 pts (50% of 38 tested patients). The CT backbone was a combination of carboplatin (Cb) plus weekly paclitaxel (wP) 4 courses (with Cb regimen AUC 5 q3W (81.1%), AUC4 q3w (5.4%) and AUC1,5 q1w (13.5%), and wP 80 mg/m²), followed by standard AC60/600 q3w for 4 courses. Out of the 37 pts (72.5%) who completed the Cb + wP 4 courses, all experienced adverse events (AEs), including 21 pts (56.8%) with at least 1 grade ≥ 3 AE (anemia 5.4%, thrombopenia 5.4%, neutropenia 51.5%, neuropathy 2.7%). Transfusion support was needed for 8 pts (21.6%). Grade ≥ 2 neuropathy occurred in 3 pts (8.1 %). Dose reduction and drug discontinuation were performed in 9 (24.3%) and 5 pts (13.5%), respectively. On the entire cohort, 15 pts (29.4%) had IrAE all grades: dysthyroidism (6 pts, 11.7%), skin toxicity (2 pts, 3.9%), adrenal insufficiency (1 pt, 2%), hypophysitis (1 pt, 2%), immune-allergic nephropathy (1 pt, 2%), suspicion of myocarditis (1 pt, 2%), hepatitis (1 pt, 2%) and ophthalmologic AE (1 pt, 2%). Consequently, after a median follow up of 5 months, pembro postponement and permanent discontinuation were performed in 7 (13,7%) and 5 pts (9,8%), respectively. At abstract submission 6 pts had breast surgery (pCR in 5 pts = 83.3%). Conclusions Our real-world data are consistent with the results of the KEYNOTE-522 trial in terms of patients characteristics. We observed a very high rate of hematological and immune related adverse events, frequently leading to dose reduction or discontinuation, underlying the need for a very close clinical management of those patients. Updated data including toxicity during the whole neoadjuvant sequence and pCR rate will be presented at the meeting.

Citation Format: Delphine Loirat, Emilie ARNAUD, Khaoula ALAOUI, Pauline VAFLARD, Sinen KORBI, Dalila MEZIANI, Lucie THIBAULT, Romain-Pacome DESMARIS, Jean-Guillaume FERON, Jean-Yves Pierga, Francois-Clement Bidard, Paul COTTU. Real-world toxicity of pembrolizumab-based neoadjuvant regimen in patients with early triple negative breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-06-09.

Abstract P5-14-01: Transcriptomic insights into lobular breast cancer biology: a retrospective analysis of the MINDACT clinical trial

Background: Invasive lobular carcinoma (ILC) represents the second most common subtype of breast cancer after invasive breast cancer of no special type (NST). In this retrospective analysis of the MINDACT trial, we aimed at identifying/refining the transcriptomic differences between: 1) estrogen receptor positive/HER2-negative (ER+/HER2-) ILC versus ER+/HER2- NST, 2) classic and non-classic ER+/HER2- ILC, and, 3) recurring and non-recurring ER+/HER2- ILC in the subgroup of patients with a low clinical and low genomic (cL/gL) risk (as defined by a modified version of Adjuvant Online! and the 70-gene signature). Patients and methods: Central pathology review was performed for histological subtype, grade and Ki67 (G.V.) for 5929/6693 (88.6%) of the patients included in the MINDACT trial (NCT00433589). Analysis of transcriptomic data adjusted for age and grade was performed using the R/Bioconductor package ‘limma’ to identify differentially expressed genes (DEGs). DEGs having absolute log-fold change (logFC)≥ 0.2 and FDR-adjusted p-value (q-value) &lt; 0.05 were considered. Gene set enrichment analyses (GSEA) of MSigDB hallmark gene sets were performed. Adjusted Cox regression models were used to evaluate the association of these hallmarks with disease free survival (DFS) and distant recurrence free survival (DRFS). Results: After central pathological review, 464 patients with ER+/HER2- ILC and 3798 patients with ER+/HER2- NST were identified. Patients with ILC were significantly older at diagnosis, had larger tumors, less axillary nodal involvement, more grade 2 tumors than patients with NST. At the transcriptomic level, we observed a high number of DEGs between these 2 subgroups, confirming their distinct phenotype. CDH1, the gene coding for E-cadherin, was as expected the most highly overexpressed gene in NST versus ILC. We further observed an increased expression of leptin (LEP), leptin receptor (LEPR), lipoprotein lipase (LPL), and the fatty acid transporter CD36 in ILC. This could suggest that ILC relied on increased lipid uptake thanks to the increased contact of ILC tumor cells with the adipocytes. IGF1 was also overexpressed in ILC versus NST, as a potential consequence of high LEP and high LEPR expression. Differences were also evident with regard to the extracellular matrix (ECM), with many collagens, matrix metalloproteinases (MMPs) and other key enzymes (e.g. LOXL1) being differentially expressed. We confirmed a decreased ER-signaling and increased PI3K/Akt signaling in ILC versus NST. Out of the 464 ER+/HER2- ILC tumors, 253 (55%) were classic ILC and 211 (45%) non-classic ILC. There were more grade 3 tumors, more highly proliferative tumors and more nodal involvement in patients with non-classic versus classic ILC. At the transcriptomic level, differences were subtler than the differences seen above. Still, a significant enrichment of the hallmarks related to cell cycle in the non-classic ILC, and of the hallmarks related to epithelial-to-mesenchymal transition, hypoxia, adipogenesis and IL6/JAK/STAT3 signaling in classic ILC was observed. Finally, 216/464 patients with ER+/HER2- ILC (47%) were assigned to the cL/gL risk group and did not receive chemotherapy. 28/216 of these patients (13%) relapsed (DFS, median FU: 8.7 years). Enrichment of hallmarks related to apoptosis, inflammatory response, hypoxia and oncogenic signaling (PI3K/Akt, Ras, c-Myc) was associated with worse survival. Conclusion: This represents, to the best of our knowledge, the largest set of gene expression data for patients with ILC, issued from a clinical trial where histology was reviewed centrally. These results could be used to personalize treatment for patients with ILC. This project is funded by the Breast Cancer Research Foundation.

Citation Format: Christine Desmedt, Ha-Linh Nguyen, François Richard, Sabine Linn, Otto Metzger, Coralie Poncet, Jelle Wesseling, Florentine Hilbers, Kim Aalders, Mauro Delorenzi, Suzette Delaloge, Jean-Yves Pierga, Etienne Brain, Suzan Vrijaldenhoven, Peter A Neijenhuis, Karen Van Baelen, Marion Maetens, Emiel Rutgers, Martine Piccart, Laura Van ’t Veer, Giuseppe Viale, Fatima Cardoso. Transcriptomic insights into lobular breast cancer biology: a retrospective analysis of the MINDACT clinical trial [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-14-01.

Abstract P4-07-54: Health related quality of life of patients treated with bevacizumab and paclitaxel as first-line treatment for HER2 negative metastatic breast cancer: impact of clinical factors

Background: Advances in screening and treatment have led to increase in breast cancer (BC) survival in recent years but prognoses for metastatic BC remain poor with poorer outcomes as health-related quality of life (HRQOL). Treatment as bevacizumab and paclitaxel for metastatic BC, although that can increase time to progression of disease, often carry toxicity and is not curative but rather palliative in intent with the goal to improve or maintain HRQOL. The aim of this work was to assess impact of clinical factors such as disease progression, toxicity on HRQOL. Methods: COMET study is a multicenter prospective single-arm cohort study in France whose main objective was to identify biological factor that could predict the clinical benefit of bevacizumab-paclitaxel combination therapy as first treatment in HER2 negative metastatic BC. HRQOL was assessed at baseline, at every cycle (every for 4 weeks) until progression and then every 3 months up to death using the EORTC QLQ-C30 questionnaire and its BC specific module, the EORTC QLQ-BR23. In this ancillary study, we targeted 5 dimensions HRQOL for the primary analyses: Global health status (GHS), physical functioning (PF), Emotional functioning (EF), fatigue (FA) and pain (PA). The primary endpoint was time until definitive deterioration (TUDD) in HRQOL scales that defined as time between inclusion and the first decrease HRQOL score ≥ 5 points compared to baseline score, with no further improvement of at least 5 points. Multivariable Cox model with time dependent covariate was performed to assess clinical factors associated with TUDD for each of the 5 target dimensions HRQOL. We performed 3 models for each dimension: model 1 including all covariate with p&lt; 0.10 in univariable; model 2 including model 1 and adjusted on cancer subtype and model 3 included model 1 stratified by cancer subtype. P value &lt; 0.01 were considered statistically significant. Results: Out of 510 patients included in COMET study, 432 patients with available HRQOL data were analyzed in this study. Median age at inclusion was 58 years (range: 29-83), and 24.4% of patients had triple negative tumor subtype. About 79 % of cancers were invasive ductal carcinoma and 43 % patients had least 3 metastasis sites at baseline. At baseline, patients reported a mean score for GHS of 57.6 (SD=22.7), for PF of 75.8 (23.2), for EF of 62.2 (25.8), for FA of 42.2 (29.60) and for PA of 38.1 (31.5). The Median TUDDs for the 5 targeted dimensions was 10.1 months [7.5-16.9] for GHS, 6.1 months [4.1-8.9] for PF, 21.6 [18.7-31.2] for EF, 10.8 [6.2-16.6] for FA and 13.6[10.1-22.5] months for PA. In multivariable analyses, Disease Progression was associated with TUDD of GHS (HR [99%CI] =2.4 [1.2-4.9] and TUDD of PF (2.1 [1.1-3.7]). After adjusted on cancer subtype, association persisted with TUDD of GHS (p=0.009). Performance Status was associated with TUDD of PF (1.6 [1.2-2.3]), and TUDD of Pain (1.6 [1.1-2.3]). Performance Status association with TUDD of PF continued after adjustment on cancer subtype (p=0.0003). Prior endocrine therapy was associated with TUDD of pain in patients with tumor with positive hormone receptor (HR+) (2.4 [1.2-4.7]). There was no factor associated with TUDD of EF and TUDD of FA. Conclusion: Results of this study have shown that among the 5 targeted dimensions HRQOL, Physical Functioning was deteriorated in the shortest time. Disease progression, base line performance status and prior endocrine therapy for HR+ subtype, are clinical factors that could influence HRQOL in HER2 negative metastatic BC treated with first line chemotherapy.

Citation Format: Oumar Billa, Sandrine Dabakuyo, Marion Chevrier, Franck Bonnetain, Isabelle Desmoulins, William Jacot, Olivier Trédan, Marc Debled, Christelle Levy, Anthony Gonçalves, Jean-Marc Ferrero, Florence Dalenc, Christelle Jouannaud, Marie-Ange Mouret-Reynier, Mireille Mousseau, Julien Grenier, Jean-Philippe Jacquin, Fatima-Zohra Toumi, Frédérique Berger, Jérôme Lemonnier, Jean-Yves Pierga. Health related quality of life of patients treated with bevacizumab and paclitaxel as first-line treatment for HER2 negative metastatic breast cancer: impact of clinical factors [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-54.

Abstract P1-03-04: Visceral fat area as a predictive factor in metastatic HER2 negative breast cancer patients treated by first line chemotherapy with weekly paclitaxel and bevacizumab

Background Obesity has previously been correlated with poorer survival in both early and metastatic breast cancer. Adipose tissues release proangiogenic factors such as Insulin-like Growth Factor and Vascular Endothelial Growth Factor that may ultimately promote tumor growth. CTscan can be used to measure the visceral fat area (VFA) and the subcutaneous fat area (SFA) on the same section. High VFA has been shown to independently predict poorer outcome in patients given first-line bevacizumab-based treatment for metastatic colorectal cancer and metastatic renal cell carcinoma. The prospective multicenter COMET trial included metastatic HER2 negative breast cancer patients receiving bevacizumab and paclitaxel as fist-line chemotherapy. This study was designed to identify and validate reliable factors to predict benefit of bevacizumab and allow for a more personalized use of this antiangiogenic agent. Our aim was to evaluate the prognostic value of BMI (Body Mass Index), VFA and SFA in the COMET cohort and their impact on the quality of life. Patients and Methods Out of the 510 patients included in the COMET trial from 9/2012 to 3/2016, 480 received bevacizumab and paclitaxel as first-line treatment and 360 had available CTscan data. VFA and SFA were measured retrospectively on the CTscans performed before chemotherapy initiation, at the level of the umbilicus with the patient in the supine position. ImageJ software was used to measure pixels with densities in the -190 HU to -30 HU range in order to delineate the subcutaneous and visceral compartments and to compute the cross-sectional area of each in cm2. These measurements were performed by a radiologist blinded to patients’ characteristics and outcomes. For VFA and SFA, we used a threshold at the median value. VFA and SFA levels were tested for their association with progression-free survival (PFS) and overall survival (OS). The impact on quality of life was based on the Global Health Status, the Physical functioning, the Emotional functioning, Fatigue and Pain scores. Results The mean age at inclusion was 57 years (range: 28-83). At initial diagnosis, the main histological type was invasive ductal carcinoma (n = 247, 80.7%). Most patients had received prior neoadjuvant/adjuvant chemotherapy (n = 245, 68.1%) and a large majority (95.4%) had less than 3 metastatic sites. One hundred and forty patients (46.7%) had histological grade II and 41% had grade III tumors. The majority of the patients had positive hormone receptor tumor (n = 238, 79.3 %) and 62 (20.7%) had triple-negative tumor subtype. The median BMI was 24.7 (range : 17-46). After a median follow-up of 60.6 months (95%CI, 60-61.3), median PFS was 9.5 months (95CI, 8.6-10.3). There was no significant correlation between BMI (p = 0.69), VFA (p = 0.24) or SFA (p = 0.58) and PFS in the univariate analysis. The median OS was 29.6 months (95CI, 25.9-32.4). BMI, VFA and SFA were not correlated with OS. Out of the 360 patients, 328 had available data regarding the quality of life. There was no impact of the VFA or the SFA on the different quality of life scores. Conclusions In our prospective cohort of 360 patients with metastatic breast cancer receiving bevacizumab and paclitaxel as first-line treatment, high VFA or high SFA were not associated with a poorer survival. VFA and SFA had no impact on quality of life.

Citation Format: Séverine Guiu, Boris Guiu, Marion Chevrier, Oumar Billa, Christelle Levy, Olivier Trédan, Isabelle Desmoulins, Marc Debled, Jean-Marc Ferrero, Christelle Jouannaud, Anthony Gonçalves, Maria Rios, Marie-Ange Mouret-Reynier, Frédérique Berger, Fatima-Zohra TOUMI, Jérôme Lemonnier, Jean-Yves Pierga, Sandrine Dabakuyo, Sophie Gourgou. Visceral fat area as a predictive factor in metastatic HER2 negative breast cancer patients treated by first line chemotherapy with weekly paclitaxel and bevacizumab [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-03-04.

Abstract GS3-09: GS3-09 Circulating Tumor Cells-driven choice of first line therapy for ER+ HER2- metastatic breast cancer: overall survival analysis of the randomized STIC CTC trial

Background: High circulating tumor cell (CTC) count (CTChigh) is a strong adverse prognostic factor in patients with metastatic breast cancer (mBC). In the STIC CTC trial (NCT01710605), run before the introduction of CDK4/6 inhibitors for ER+/HER2- mBC, we showed that CTC count (CTC arm) was non inferior to clinician’s choice (standard arm) on progression-free survival (PFS) to guide first line treatment selection between chemotherapy (CT) and endocrine therapy (ET) (Bidard et al., JAMA Oncol 2021). Of note, patients who had treatment escalated from ET (a priori clinician choice) to CT in the CTC arm, had a significantly longer PFS. We report here overall survival (OS) results of this multicenter CTC clinical utility trial.

Methods: In the CTC arm, N=377 patients had their treatment determined by baseline CTC count: CT if CTChigh (≥5 CTCs/7.5 mL, CellSearch®), ET if CTClow. In the standard arm (N=378 patients), the choice was left to the investigator: CT if clinical high risk (Clinhigh), ET if clinical low risk (Clinlow). Therefore, patients with discordant Clinlow/CTChigh or Clinhigh/CTClow profiles had their first line treatment escalated from ET (standard arm) to CT (CTC arm) or de-escalated from CT (standard arm) to ET (CTC arm), respectively. Patients with concordant Clinlow/CTClow and Clinhigh/CTChigh profiles received ET and CT in both arms, respectively.

Results: Among 755 randomized patients, N=189 (25.0%) had a Clinlow/CTChigh profile, N=103 (13.6%) Clinhigh/CTClow, N=363 (48.2%) Clinlow/CTClow and N=100 (13.2%) Clinhigh/CTChigh. OS was analyzed after a median follow-up of 57 months and 382 events (50.6%). In the Clinlow/CTChigh subgroup, CT in the CTC arm led a longer OS (mOS: 51.8 months [43.3-NR]) than ET in the standard arm (35.4 months [30.4-45.4]; HR=0.53 [0.36-0.78], p=0.001). In patients Clinhigh/CTClow, no significant difference was observed whether they received CT (standard arm) or ET (CTC arm) (45.9 months [36.3-59.8] vs 49.4 months [35.4-65.4]; HR=0.88 [0.51-1.51], p=0.63). Pooling the two discordant groups (Clinlow/CTChigh or Clinhigh/CTClow), the CTC-driven strategy was superior to the clinician-driven treatment decision (HR=0.63 [0.46-0.86], p=0.02). Pooling all concordant and discordant groups together, a median OS of 45.5 (95%CI=[40.9-51.1]) and 51.3 months [46.8-55.1] was observed in the standard and CTC arms, respectively (HR=0.84 [0.69-1.03], p=0.10).

Conclusions: Prognostic information brought by CTC or standard factors is discordant in 40% of patients with ER+ HER2- mBC. In case of a discordant estimate, the STIC CTC trial shows the superiority on OS of the CTC-driven treatment decision strategy. These results also suggest a possible clinical utility of CTC to adjust systemic treatment for mBC in second and later lines, after progression on CDK4/6 inhibitors.

Funding:The study was funded by Institut Curie; the French National Cancer Institute (INCa), as part of the Programme de Soutien aux Techniques Innovantes Coûteuses 2011 (STIC 2011); and Menarini Silicon Biosystems (Castel Maggiore, Italy).

Evolution of synchronous female bilateral breast cancers and response to treatment

Synchronous bilateral breast cancer (sBBC) occurs after both breasts have been affected by the same germline genetics and environmental exposures. Little evidence exists regarding immune infiltration and response to treatment in sBBCs. Here we show that the impact of the subtype of breast cancer on levels of tumor infiltrating lymphocytes (TILs, n = 277) and on pathologic complete response (pCR) rates (n = 140) differed according to the concordant or discordant subtype of breast cancer of the contralateral tumor: luminal breast tumors with a discordant contralateral tumor had higher TIL levels and higher pCR rates than those with a concordant contralateral tumor. Tumor sequencing revealed that left and right tumors (n = 20) were independent regarding somatic mutations, copy number alterations and clonal phylogeny, whereas primary tumor and residual disease were closely related both from the somatic mutation and from the transcriptomic point of view. Our study indicates that tumor-intrinsic characteristics may have a role in the association of tumor immunity and pCR and demonstrates that the characteristics of the contralateral tumor are also associated with immune infiltration and response to treatment.

Alpelisib and fulvestrant in PIK3CA-mutated hormone receptor-positive HER2-negative advanced breast cancer included in the French early access program

SOLAR-1 and BYLieve trials documented the efficacy of the PI3K-inhibitor alpelisib in pre-treated PIK3CA-mutant, hormone receptor-positive, HER2-negative (HR+/HER2-) advanced breast cancer (ABC) patients. We report here real-life data of patients prospectively registered in the French alpelisib early access program (EAP) opened to PIK3CA-mutant HR+/HER2- ABC patients treated with alpelisib and fulvestrant. Primary endpoint was PFS by local investigators using RECIST1.1. Eleven centers provided individual data on 233 consecutive patients. Patients had received a median number of 4 (range: 1-16) prior systemic treatments for ABC, including CDK4/6 inhibitor, chemotherapy, fulvestrant and everolimus in 227 (97.4%), 180 (77.3%), 175 (75.1%) and 131 (56.2%) patients, respectively. After a median follow-up of 7.1 months and 168 events, median PFS was 5.3 months (95% CI: 4.7-6.0). Among 186 evaluable patients, CBR at 6 months was 45.3% (95% CI: 37.8-52.8). In multivariable analysis, characteristics significantly associated with a shorter PFS were age < 60 years (HR = 1.5, 95% CI = 1.1-2.1), >5 lines of prior treatments (HR = 1.4, 95% CI = 1.0-2.0) and the C420R PI3KCA mutation (HR = 4.1, 95% CI = 1.3-13.6). N = 91 (39.1%) patients discontinued alpelisib due to adverse events. To our knowledge, this is the largest real-life assessment of alpelisib efficacy. Despite heavy pre-treatments, patients derived a clinically relevant benefit from alpelisib and fulvestrant.

Concurrent Olaparib and Radiotherapy in Patients With Triple-Negative Breast Cancer: The Phase 1 Olaparib and Radiation Therapy for Triple-Negative Breast Cancer Trial

Importance

Triple-negative breast cancer (TNBC) cells are sensitive to poly(adenosine diphosphate ribose) polymerase (PARP) inhibitors used as radiosensitizers. Whether combining PARP inhibitors with radiotherapy in patients with TNBC would enhance the biological effectiveness of the irradiation and improve locoregional control is unclear.

Objective

To assess the safety and tolerability of PARP inhibition with olaparib used concurrently with radiotherapy in patients with TNBC with residual disease after neoadjuvant chemotherapy.

Design, Setting, and Participants

This phase 1 prospective dose-escalation trial (Olaparib and Radiation Therapy for TNBC [RadioPARP] trial) using a time-to-event continual reassessment method was performed from September 2017 to November 2019, with follow-up until November 2021. Participants had an incomplete pathologic response after neoadjuvant chemotherapy or unresectable TNBC despite previous neoadjuvant chemotherapy, an Eastern Cooperative Oncology Group Performance Status score of 0 or 1, and adequate organ functions.

Interventions

Olaparib was administered orally in the form of tablets and given at increasing doses (50 mg, 100 mg, 150 mg, or 200 mg twice daily). Olaparib therapy was started 1 week before radiotherapy and was continued concomitantly with radiotherapy. After breast-conserving surgery, a total dose of 50.4 Gy was delivered to the whole breast, with a 63-Gy simultaneously integrated boost to the tumor bed for patients younger than 60 years. After radical mastectomy or for unresectable tumors despite neoadjuvant chemotherapy, a total dose of 50.0 Gy was delivered to the chest wall (after mastectomy) or to the whole breast (for unresectable tumors). Regional lymph node stations could be treated with a total dose of 50.0 Gy to 50.4 Gy in cases of node-positive disease.

Main Outcomes and Measures

Main outcomes were the safety and tolerability of PARP inhibition with radiotherapy for early-stage, high-risk TNBC. Secondary outcomes included overall survival (OS) and event-free survival (EFS).

Results

Among the 24 patients included in the trial (100% female; median age, 46 years [range, 25-74 years]), no dose-limiting toxic effects were observed, and olaparib was escalated to 200 mg twice daily without reaching the maximum tolerated dose. No late treatment-related grade 3 or greater toxic effect was observed, and the maximum observed treatment-related toxic effects at the 2-year follow-up were grade 2 breast pain, fibrosis, and deformity in 1 patient (4.2%). Three-year OS and EFS were 83% (95% CI, 70%-100%) and 65% (95% CI, 48%-88%), respectively. Homologous recombination status was not associated with OS or EFS.

Conclusions and Relevance

The findings of this phase 1 dose-escalation trial suggest that PARP inhibition with olaparib concurrently with radiotherapy for early-stage, high-risk TNBC is well tolerated and should continue to be evaluated in further clinical trials.

Trial Registration

ClinicalTrials.gov Identifier: NCT03109080.

Switch to fulvestrant and palbociclib versus no switch in advanced breast cancer with rising ESR1 mutation during aromatase inhibitor and palbociclib therapy (PADA-1): a randomised, open-label, multicentre, phase 3 trial

BACKGROUND

In advanced oestrogen receptor-positive, HER2-negative breast cancer, acquired resistance to aromatase inhibitors frequently stems from ESR1-mutated subclones, which might be sensitive to fulvestrant. The PADA-1 trial aimed to show the efficacy of an early change in therapy on the basis of a rising ESR1 mutation in blood (bESR1^mut), while assessing the global safety of combination fulvestrant and palbociclib.

METHODS

We did a randomised, open-label, phase 3 trial in 83 hospitals in France. Women aged at least 18 years with oestrogen receptor-positive, HER2-negative advanced breast cancer and an Eastern Cooperative Oncology Group performance status of 0-2 were recruited and monitored for rising bESR1^mut during first-line aromatase inhibitor (2·5 mg letrozole, 1 mg anastrozole, or 25 mg exemestane, orally once per day, taken continuously) and palbociclib (125 mg orally once per day on days 1-21 of a 28-day cycle) therapy. Patients with newly present or increased bESR1^mut in circulating tumour DNA and no synchronous disease progression were randomly assigned (1:1) to continue with the same therapy or to switch to fulvestrant (500 mg intramuscularly on day 1 of each 28-day cycle and on day 15 of cycle 1) and palbociclib (dosing unchanged). The randomisation sequence was generated within an interactive web response system using a minimisation method (with an 80% random factor); patients were stratified according to visceral involvement (present or absent) and the time from inclusion to bESR1^mut detection (<12 months or ≥12 months). The co-primary endpoints were investigator-assessed progression-free survival from random assignment, analysed in the intention-to-treat population (ie, all randomly assigned patients), and grade 3 or worse haematological adverse events in all patients. The trial is registered with Clinicaltrials.gov (NCT03079011), and is now complete.

FINDINGS

From March 22, 2017, to Jan 31, 2019, 1017 patients were included, of whom 279 (27%) developed a rising bESR1^mut and 172 (17%) were randomly assigned to treatment: 88 to switching to fulvestrant and palbociclib and 84 patients to continuing aromatase inhibitor and palbociclib. At database lock on July 31, 2021, randomly assigned patients had a median follow-up of 35·3 months (IQR 29·2-41·4) from inclusion and 26·0 months (13·8-34·3) from random assignment. Median progression-free survival from random assignment was 11·9 months (95% CI 9·1-13·6) in the fulvestrant and palbociclib group versus 5·7 months (3·9-7·5) in the aromatase inhibitor and palbociclib group (stratified HR 0·61, 0·43-0·86; p=0·0040). The most frequent grade 3 or worse haematological adverse events were neutropenia (715 [70·3%] of 1017 patients), lymphopenia (66 [6·5%]), and thrombocytopenia (20 [2·0%]). The most common grade 3 or worse adverse events in step 2 were neutropenia (35 [41·7%] of 84 patients in the aromatase inhibitor and palbociclib group vs 39 [44·3%] of 88 patients in the fulvestrant and palbociclib group) and lymphopenia (three [3·6%] vs four [4·5%]). 31 (3·1%) patients had grade 3 or worse serious adverse events related to treatment in the overall population. Three (1·7%) of 172 patients randomly assigned had one serious adverse event in step 2: one (1·2%) grade 4 neutropenia and one (1·2%) grade 3 fatigue among 84 patients in the aromatase inhibitor and palbociclib group, and one (1·1%) grade 4 neutropenia among 88 patients in the fulvestrant and palbociclib group. One death by pulmonary embolism in step 1 was declared as being treatment related.

INTERPRETATION

PADA-1 is the first prospective randomised trial showing that the early therapeutic targeting of bESR1^mut results in significant clinical benefit. Additionally, the original design explored in PADA-1 might help with tackling acquired resistance with new drugs in future trials.

FUNDING

Pfizer.

Trastuzumab Deruxtecan in Previously Treated HER2-Low Advanced Breast Cancer

BACKGROUND

Among breast cancers without human epidermal growth factor receptor 2 (HER2) amplification, overexpression, or both, a large proportion express low levels of HER2 that may be targetable. Currently available HER2-directed therapies have been ineffective in patients with these "HER2-low" cancers.

METHODS

We conducted a phase 3 trial involving patients with HER2-low metastatic breast cancer who had received one or two previous lines of chemotherapy. (Low expression of HER2 was defined as a score of 1+ on immunohistochemical [IHC] analysis or as an IHC score of 2+ and negative results on in situ hybridization.) Patients were randomly assigned in a 2:1 ratio to receive trastuzumab deruxtecan or the physician's choice of chemotherapy. The primary end point was progression-free survival in the hormone receptor-positive cohort. The key secondary end points were progression-free survival among all patients and overall survival in the hormone receptor-positive cohort and among all patients.

RESULTS

Of 557 patients who underwent randomization, 494 (88.7%) had hormone receptor-positive disease and 63 (11.3%) had hormone receptor-negative disease. In the hormone receptor-positive cohort, the median progression-free survival was 10.1 months in the trastuzumab deruxtecan group and 5.4 months in the physician's choice group (hazard ratio for disease progression or death, 0.51; P<0.001), and overall survival was 23.9 months and 17.5 months, respectively (hazard ratio for death, 0.64; P = 0.003). Among all patients, the median progression-free survival was 9.9 months in the trastuzumab deruxtecan group and 5.1 months in the physician's choice group (hazard ratio for disease progression or death, 0.50; P<0.001), and overall survival was 23.4 months and 16.8 months, respectively (hazard ratio for death, 0.64; P = 0.001). Adverse events of grade 3 or higher occurred in 52.6% of the patients who received trastuzumab deruxtecan and 67.4% of those who received the physician's choice of chemotherapy. Adjudicated, drug-related interstitial lung disease or pneumonitis occurred in 12.1% of the patients who received trastuzumab deruxtecan; 0.8% had grade 5 events.

CONCLUSIONS

In this trial involving patients with HER2-low metastatic breast cancer, trastuzumab deruxtecan resulted in significantly longer progression-free and overall survival than the physician's choice of chemotherapy. (Funded by Daiichi Sankyo and AstraZeneca; DESTINY-Breast04 ClinicalTrials.gov number, NCT03734029.).

Modeling the Prognostic Impact of Circulating Tumor Cells Enumeration in Metastatic Breast Cancer for Clinical Trial Design Simulation

Despite the strong prognostic stratification of circulating tumor cells (CTCs) enumeration in metastatic breast cancer (MBC), current clinical trials usually do not include a baseline CTCs in their design. This study aimed to generate a classifier for CTCs prognostic simulation in existing datasets for hypothesis generation in patients with MBC. A K-nearest neighbor machine learning algorithm was trained on a pooled dataset comprising 2436 individual MBC patients from the European Pooled Analysis Consortium and the MD Anderson Cancer Center to identify patients likely to have CTCs ≥ 5/7 mL blood (StageIVaggressive vs StageIVindolent). The model had a 65.1% accuracy and its prognostic impact resulted in a hazard ratio (HR) of 1.89 (Simulatedaggressive vs SimulatedindolentP < .001), similar to patients with actual CTCs enumeration (HR 2.76; P < .001). The classifier's performance was then tested on an independent retrospective database comprising 446 consecutive hormone receptor (HR)-positive HER2-negative MBC patients. The model further stratified clinical subgroups usually considered prognostically homogeneous such as patients with bone-only or liver metastases. Bone-only disease classified as Simulatedaggressive had a significantly worse overall survival (OS; P < .0001), while patients with liver metastases classified as Simulatedindolent had a significantly better prognosis (P < .0001). Consistent results were observed for patients who had undergone CTCs enumeration in the pooled population. The differential prognostic impact of endocrine- (ET) and chemotherapy (CT) was explored across the simulated subgroups. No significant differences were observed between ET and CT in the overall population, both in terms of progression-free survival (PFS) and OS. In contrast, a statistically significant difference, favoring CT over ET was observed among Simulatedaggressive patients (HR: 0.62; P = .030 and HR: 0.60; P = .037, respectively, for PFS and OS).

No Impact of Seasonality of Diagnoses on Baseline Tumor Immune Infiltration, Response to Treatment, and Prognosis in BC Patients Treated with NAC

Simple Summary

High tumor-infiltrating lymphocyte (TIL) levels are associated with an increased response to neoadjuvant chemotherapy (NAC) in breast cancer (BC). The seasonal fluctuation of TILs in breast cancer is poorly documented. In this study, we compared pre- and post-treatment immune infiltration, the treatment response as assessed by means of pathological complete response (pCR) rates, and survival according to the seasonality of BC diagnoses in a clinical cohort of patients treated with NAC. We found no association between seasonality and baseline TIL levels or pCR rates. We found that post-NAC stromal lymphocyte infiltration was lower when cancer was diagnosed in the summer, especially in the subgroup of patients with TNBC. Our data do not support the hypothesis that the seasonality of diagnoses has a major impact on the natural history of BC treated with NAC.

Abstract

Breast cancer (BC) is the most common cancer in women worldwide. Neoadjuvant chemotherapy (NAC) makes it possible to monitor in vivo response to treatment. Several studies have investigated the impact of the seasons on the incidence and detection of BC, on tumor composition, and on the prognosis of BC. However, no evidence is available on their association with immune infiltration and the response to treatment. The objective of this study was to analyze pre- and post-NAC immune infiltration as assessed by TIL levels, the response to treatment as assessed by pathological complete response (pCR) rates, and oncological outcomes as assessed by relapse-free survival (RFS) or overall survival (OS) according to the seasonality of BC diagnoses in a clinical cohort of patients treated with neoadjuvant chemotherapy. Out of 1199 patients, the repartition of the season at BC diagnosis showed that 27.2% were diagnosed in fall, 25.4% in winter, 24% in spring, and 23.4% in summer. Baseline patient and tumor characteristics, including notable pre-NAC TIL levels, were not significantly different in terms of the season of BC diagnosis. Similarly, the pCR rates were not different. No association for oncological outcome was identified. Our data do not support the idea that the seasonality of diagnoses has a major impact on the natural history of BC treated with NAC.

Safety and tolerability of olaparib combined with breast radiotherapy in patients with triple-negative breast cancer: Final results of the RADIOPARP phase 1 trial

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Background: Preclinical studies have demonstrated that triple-negative breast cancer (TNBC) cells were sensitive to PARP inhibitors when used as radiosensitizers. Combining PARP-inhibitors with radiotherapy may consequently enhance the biological effectiveness of the irradiation, leading to improved locoregional control in TNBC patients. We aimed to establish the appropriate dosing and the safety profile of Olaparib used as a radiosensitizer in combination with radiotherapy in TNBC patients with residual disease after neoadjuvant chemotherapy. Methods: RADIOPARP (NCT03109080) was a prospective phase I dose-escalation trial establishing the tolerance profile of Olaparib combined with breast radiotherapy in high-risk early TNBC patients. Inclusion criteria were resected TNBC with non-complete pathological response after neoadjuvant chemotherapy, or unresectable TNBC despite prior neoadjuvant chemotherapy. Olaparib was started seven days before irradiation and continued during radiotherapy. A time-to-event continual reassessment method was used to increase Olaparib through four increasing dose levels (50mg, 100mg, 150mg or 200mg twice a day) with a 25% maximum probability rate of dose-limiting toxicities (DLT). Radiotherapy delivered 50 Gy to the breast or to the chest wall, with or without lymph node irradiation. Toxicities were graded according to CTCAE (version 4.03). Homologous recombination (HR) proficiency status was genetically determined based on shallow whole genome sequencing. Results: Twenty-four TNBC patients were enrolled between 09/2017 and 11/2019. Olaparib was escalated to 200 mg twice a day without DLT and the MTD was not reached. With a median follow-up of 34 months, no late treatment-related grade ≥ 3 toxicity was observed, and the maximum observed toxicities were limited to grade 2 breast pain (n=2), fibrosis (n=2), deformity (n=1) and telangiectasia (n=1). Three-year OS and EFS were 83% [95% CI: 70%-100%] and 65% [51%-91%], respectively. HR proficiency status was not associated with OS and EFS. Conclusions: Olaparib used as a radiosensitizer in combination with radiotherapy in TNBC patients was well-tolerated. The MTD was not reached, and no significant late toxicity was reported. For future trials evaluating the anti-tumor efficacy of this combination, an Olaparib dose of 200 mg twice a day should be considered. Clinical trial information: NCT03109080.

Oral Etoposide and Trastuzumab Use for HER2-Positive Metastatic Breast Cancer: A Retrospective Study from the Institut Curie Hospitals

BACKGROUND

The TOP2A and ERBB2 genes are co-amplified in about 40% of HER2 positive (HER2+) breast cancers. Oral etoposide (VP16), an inhibitor of topoisomerase-II (encoded by TOP2A), has demonstrated clinical activity in metastatic breast cancer (MBC). The benefit of oral VP16 combined with trastuzumab (VP16-T) in HER2+ MBC has not yet been evaluated.

METHODS

Patients treated at the Institut Curie Hospitals with VP16-T for HER2+ MBC were retrieved by an in silico search. Progression-free survival (PFS), overall survival (OS), response rate, prolonged PFS (defined as at least 6 months), clinical benefit, and toxicity were assessed. The co-amplification of ERBB2 and TOP2A was assessed by shallow whole genome sequencing on tumor tissue whenever available.

RESULTS

Forty-three patients received VP16-T after a median number of six prior treatment lines for HER2+ MBC. Median PFS and OS were 2.9 months (95% CI [2.4-4.7]) and 11.3 months (95% CI [8.3-25.0]), respectively. Three patients had a complete response, while 12/40 (30%) experienced clinical benefit. Only three patients stopped treatment for toxicity. Seven (35%) patients displayed a TOP2A/ERBB2 co-amplification. No statistically significant correlation was found between outcome and TOP2A/ERBB2 co-amplification.

CONCLUSION

Our analysis suggests a favorable efficacy and toxicity profile for VP16-T in patients with heavily pretreated HER2+ MBC.

Real-Time Detection of ESR1 Mutation in Blood by Droplet Digital PCR in the PADA-1 Trial: Feasibility and Cross-Validation with NGS

The clinical actionability of circulating tumor DNA requires sensitive detection methods with a short turnaround time. In the PADA-1 phase 3 trial (NCT03079011), metastatic breast cancer patients treated with an aromatase inhibitor and palbociclib were screened every 2 months for activating ESR1 mutations in blood (bESR1_mut). We report the feasibility of the droplet digital polymerase chain reaction (ddPCR) and cross-validation with next-generation sequencing (NGS). bESR1_mut testing was centralized in two platforms using the same ddPCR assay. Results were reported as copies/mL of plasma and mutant allele frequency (MAF). We analyzed 200 positive ddPCR samples with an NGS assay (0.5-1% sensitivity). Overall, 12,552 blood samples were collected from 1017 patients from 83 centers. Among the 12,525 available samples with ddPCR results, 11,533 (92%) were bESR1_mut-negative. A total of 267 patients newly displayed bESR1_mut (26% patients/2% samples) with a median copy number of 14/mL (range: 4-1225) and a median MAF of 0.83% (0.11-35), 648 samples (20% patients/5% samples) displayed persistent bESR1_mut, and 77 (<1%) samples encountered a technical failure. The median turnaround time from blood drawing to result notification was 13 days (Q1:9; Q3:21 days). Among 200 ddPCR-positive samples tested, NGS detected bESR1_mut in 168 (84%); 25 of the 32 cases missed by NGS had low MAF and/or low coverage. In these 200 samples, bESR1_mut MAF by both techniques had an excellent intraclass correlation coefficient (ICC = 0.93; 95% CI [0.85; 0.97]). These results from a large-scale trial support the feasibility and accuracy of real-time bESR1_mut tracking by ddPCR, opening new opportunities for therapeutic interventions.

Abstract P2-13-27: Infusion-related reactions in patients receiving pertuzumab and trastuzumab: A retrospective study

BACKGROUND: The use of two anti-HER2 monoclonal antibodies (mAbs) (pertuzumab and trastuzumab) combined with taxanes is the standard of care for first line treatment in HER2-positive metastatic breast cancer (mBC). Infusion related reactions (IRR) during first administration of anti-HER2 mAb have been reported. Reintroduction of the causal drugs is often possible, but there is no data to identify patients at highest risk of developing IRR and modalities of safe reintroduction. The aim of this study was to report patients who experienced IRR during anti-HER2 mAbs infusions at Institut Curie Hospitals (ICH) and to describe these reactions. METHODS: All IRR cases must be reported to the ICH pharmacies. We retrospectively inspected the electronic record of patients who experienced an IRR during pertuzumab (Pmab) and trastuzumab (Tmab). We collected patients’ characteristics, grade of IRR and outcomes. RESULTS: From January 2013 to December 2020, a total of 223 patients had at least one Pmab+Tmab infusion as part of their BC treatment. Among them, 28 patients (8%) with anti-HER2 mAb IRR were identified. All patients but one had an HER2-positive BC; the HER2-negative case was a HER3-mutant mBC. Twelve patients (43%) had de novo mBC. Twenty-six patients (93%) received Pmab+Tmab as first line treatment for mBC. Ten patients were previously exposed to Tmab and three to Pmab+Tmab for (neo)adjuvant treatment. At IRR onset, 21 patients (75%) had liver metastasis, with more than five liver metastases for 19 of them. Fifteen patients (55%) had liver enzymes upper normal limit. IRR occurred during first anti-HER2-mAb infusion in 22 patients (79%) despite pre-treatment with antihistaminic and/or glucosteroids for taxanes. The other IRR were reported at the 2nd, 5th, 6th, 8th and &gt; 10th cycle of Pmab+Tmab. Sixteen IRR (57%) were attributed to Pmab infusion, 9 (32%) to Tmab infusion and 3 (11%) to Tmab and/or Pmab. Al IRR were declared to the pharmacovigilance agency. Majority of reactions were mild to moderate (54% of grade 2). Most frequent symptoms associated with IRR were: thrills (68%), hyperthermia (64%); low oxygen saturation (36%), pain (25%), hypotension (21%), cutaneous (18%) and digestive (18%) reaction. Three patients were transferred to ICU. One death was attributed to anti-HER2 mAb IRR (death was attributed to respiratory distress during the first Tmab infusion). Reintroduction off Pmab+Tmab was performed in 18 patients, after pre-treatment with antihistaminic and/or glucosteroids and with vital function monitoring in conventional hospitalization. No recurrence of IRR was observed in 15/18 patients. For the 3 patients with recurrent IRR, symptoms were mild to moderate. Objective response to anti-HER2 treatments was observed in twenty three patients (82%; 8 complete responses; 15 partial responses). Median PFS was 16 months. CONCLUSIONS: Most anti-Her2-mAb IRR occurs during first infusion, are mild to moderate and do not require a transfer in ICU. Our study suggests that patients with high liver burden might be over-represented among those experiencing an IRR. Reintroduction of Pmab+Tmab was safe in most patients, allowing the continuation of the anti-HER2 dual blockade.

Citation Format: Delphine Loirat, Juliette Logeart, Pauline Vaflard, Aurélien Noret, Mathilde Saint-Ghislain, Edith Borcoman, Audrey Hurgon, Cyrille Cros, Thomas Genevee, Audrey Bellesoeur, Francesco Ricci, Florence Lerebours, Laurence Escalup, Marie-Paule Sablin, François-Clément Bidard, Paul H. Cottu, Jean-Yves Pierga. Infusion-related reactions in patients receiving pertuzumab and trastuzumab: A retrospective study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-13-27.

Abstract PD8-02: Trastuzumab deruxtecan (T-DXd) for advanced breast cancer patients (ABC), regardless HER2 status: A phase II study with biomarkers analysis (DAISY)

Background: The HER2-targeted antibody-drug conjugate (ADC) trastuzumab deruxtecan (T-DXd) demonstrated efficacy in heavily pretreated HER2-over- and HER2-low expressing ABC (1, 2). We aimed to assess the activity of T-DXd in HER2-over-, HER2-low and HER2-nul expressing ABC, to describe the drug mechanisms of action in the 3 cohorts and to identify biomarkers associated to drug response or resistance. Study Description: DAISY is a multicenter, open-label phase II trial designed to assess the efficacy of single agent T-DXd at 5.4 mg/kg dose in ABC with extensive biomarkers analysis. Three cohorts of patients were included: Cohort 1 (HER2 over-expressing: HER2 3+ on immunohistochemistry (IHC) or HER2 IHC2+/in situ hybridization [ISH]+), Cohort 2 (HER2 low-expressing: IHC1+ or IHC2+/ISH-) and cohort 3 (HER2-nul: IHC0+). Biopsy of metastatic sites was performed: at baseline, on treatment (mandatory for cohort 1, optional for cohort 2/3) and at tumor progression; blood samples for ctDNA were collected at baseline. The primary endpoint was the Best Overall Response (BOR) in each cohort, according to the investigator assessment. Secondary endpoints were BOR by central assessment, clinical benefit rate, duration of response (DOR), progression-free (PFS), overall survival (OS) and safety. Results:185 women and 1 man were enrolled between November 2019 and March 2021. Among the patients enrolled in the safety population (see Table 1), median (range) age was 55 (24-82) years, all received at least one prior line of therapy and 12 patients were TN. Table 2 shows investigator-reported T-Dxd activity in the 3 cohorts at a median follow-up of 10.1 months [95%CI: 9.2-11.1]. A total of 170 patients (95%) had at least one treatment-related toxicity. Key grade ≥3 treatment-related toxicities included neutropenia (10.6% of patients), fatigue (5.6%), leucopenia (4.5%), vomiting (4.5%) and anemia (3.4%). A total of 4 patients had drug-related interstitial lung disease or pneumonitis (grade 1 in 3 patients and grade 2 in 1 patient), 11 patients discontinued treatment due to treatment-related adverse events. No drug-related deaths occurred. Conclusions: T-DXd showed clinically meaningful activity in patients with HER2-overexpressing ABC and interestingly also in those with HER2low and HER2-nul ABC. Safety profile was consistent with previous reports. 1.Modi S et al N Engl J Med 2020 2.Mosi S et al J Clin Oncol 2020

Table 1.Analysis populationsTotalCohort 1 (HER2 over-expressing)Cohort 2 (HER2 low-expressing)Cohort 3 (HER2 non-detected)Enrolled population186727440Safety population*179687338 (including 12 TN)Full analysis Set**176687236TN: Triple Negative. *: safety population = enrolled population except 7 patients who did not receive at least one dose of study drug. **: Full Analysis Set = safety population except 3 patients (2 who did not have a valid first post-baseline assessment of disease status or who did not have progressive disease and 1 who did not have at least one radiologically measurable lesion according to RECIST v1.1)

Table 2.T-DXd activity in the three cohorts according to investigator assessmentTotalCohort 1Cohort 2Cohort 3BOR confirmedn/N82/176 (46.6%)47/68 (69.1%)24/72 (33.3%)11/36 (30.6%)[95%CI][39.1; 54.2][56.7; 79.8][22.7; 45.4]16.3; 48.1]Median DORmonths7.69.97.66.8[95%CI][6.2; 9.7][5.4; NR][4.4; 8.7][2.8; 8.3]Median PFSmonths6.911.16.74.2[95%CI][6.7; 8.7][8.4; NR][4.6; 8.5][2.1; 6.9]NR: Not Reached

Citation Format: Véronique Diéras, Elise Deluche, Amélie Lusque, Barbara Pistilli, Thomas Bachelot, Jean-Yves Pierga, Frédéric Viret, Christelle Levy, Laura Salabert, Fanny Le Du, Florence Dalenc, Christelle Jouannaud, Laurence Venat-Bouvet, Jean-Philippe Jacquin, Xavier Durando, Thierry Petit, Céline Mahier - Aït Oukhatar, Thomas Filleron, Maria Fernanda Mosele, Magali Lacroix-Triki, Agnès Ducoulombier, Fabrice André. Trastuzumab deruxtecan (T-DXd) for advanced breast cancer patients (ABC), regardless HER2 status: A phase II study with biomarkers analysis (DAISY) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD8-02.

Abstract P2-13-26: Trastuzumab deruxtecan in previously treated HER2-positive metastatic or unresectable breast cancer (BC): First real-life data from the cohort temporary authorization for use (cATU) program in France

Background Trastuzumab deruxtecan (T-DXd) is an antibody-drug conjugate (ADC) composed of an HER2-directed antibody and a topoisomerase I inhibitor covalently linked via a tetrapeptide-based cleavable linker. In DESTINY-Breast01, tolerability and efficacy of T-DXd including overall response rate, progression-free survival, duration of response and overall survival have been demonstrated for HER2-positive metastatic and/or unresectable BC in patients (pts) relapsing after 2 or more anti-HER2-based regimens. In France, rapid and fair access to innovative drugs outside clinical trials, prior to their marketing authorization in a given indication, is granted by the French Health Agency, ANSM (Agence Nationale de Sécurité du Médicament et des Produits de Santé), through cATU program. Here we report first real world evidence data from cATU program in HER2+ BC pts treated with T-DXd. Methods T-DXd 5.4mg/kg was given intravenously in monotherapy every 3 weeks in HER2-positive metastatic and/or unresectable BC pts who had previously received at least 2 lines of anti-HER2 regimens in the metastatic setting. Eligible pts needed to have normal neutrophil count and no left ventricular dysfunction. Pts with active or history of interstitial lung disease (ILD), pneumonitis, severe pulmonary disease were excluded. Clinical, biological and safety data were collected until the end of cATU, as well as treatment response according to RECIST 1.1., dose modification, treatment interruption and discontinuation. Analysis was performed on March 31th, 2021 on the basis of available collected data. Results From September 30th, 2020 to March 31th, 2021, 155 centers requested at least one ATU for a total of 539 adult pts; 468 requests were accepted and 71 were refused as they did not meet eligibility criteria. T-DXd was received by 459 pts with the following characteristics: 99.1% were women, median age was 58 years, 90.4% had a ECOG score of 0-1, 98.9% had initial HER2-positive BC (IHC 3+ or IHC 2+/ISH+), 67% were hormone receptor positive. The main sites of metastases were bones (57.3%), lymph nodes (51.6%), lungs (36.2%), liver (33.1%), brain (28.1%) and cutaneous/subcutaneous (13.9%). Median time between initial diagnosis of primary BC and inclusion was 6.6 years (range: 6.6 months - 33.9 years). 81.7% of pts had previously received radiotherapy and 76.5% underwent surgery. The median number of prior cancer regimens in the metastatic setting was 4 (range: 2-22). 21.1% received 2 prior lines of metastatic treatments, 19.6% received 3 lines and 59.3% received 4 lines or more. 94.8% pts received prior trastuzumab emtansine, and 79.3% had prior pertuzumab. During follow-up, data on tumor assessment were available for 160 pts. Of these, 56.7% had complete or partial response and 12.1% had progression. Of the 459 treated pts, 97 pts (21.1%) experienced ≥ 1 Adverse Drug Reaction (ADR) including 41 pts (8.9%) with ≥ 1 serious ADR. Most frequent ADRs were related to gastrointestinal toxicity (35.4%). During cATU, 17 cases (3.7%) with ILD or considered as ILD were reported but no cases had a fatal outcome (only grade 1 or 2 when reported by physicians). 13 fatal cases were reported (no drug-related deaths, attributed by physician). ADRs leading to T-DXd discontinuation were reported in 4 pts (0.9%). Dose reductions were reported in 17 pts (3.7%) and 21 pts (4.6%) had temporary interruptions. Conclusions We report here the first real world data from the French cATU in HER2-positive BC pts treated by T-DXd. The enrolment of 468 pts in 6 months illustrated the unmet medical need for this population. T-DXd had antitumor activity with a similar response rate to that reported in previous clinical studies. T-DXd was well tolerated and no new safety signals were observed.

Citation Format: Thierry Petit, Nawale Hajjaji, Eric-Charles Antoine, Marc-Antoine Benderra, Michel Gozy, Cyril Foa, Jean-Loup Mouysset, Julien Grenier, Mireille Mousseau, Audrey Mailliez, Mahasti Saghatchian, Emma Lachaier, Isabelle Desmoulins, Audrey Hennequin, Patricia Maes, Delphine Loirat, Francesco Ricci, Véronique Diéras, Dominique Berton, Florence Lai Tiong, Luis Teixeira, Nadine Dohollou, Christelle Lévy, Thomas Bachelot, Jean-Yves Pierga. Trastuzumab deruxtecan in previously treated HER2-positive metastatic or unresectable breast cancer (BC): First real-life data from the cohort temporary authorization for use (cATU) program in France [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-13-26.

Abstract GS2-07: Updated results from a phase 3 randomized clinical trial in participants (pts) with 1-3 positive lymph nodes (LN), hormone receptor-positive (HR+) and HER2-negative (HER2-) breast cancer (BC) with recurrence score (RS) ≤ 25 randomized to endocrine therapy (ET) +/- chemotherapy (CT): SWOG S1007 (RxPONDER)

Background: We previouslyreported that invasive disease-free survival (IDFS), the primary outcome, and distantdisease-free survival (DDFS), a secondary outcome, differed by menopausalstatus in a pre-specified analysis. Here,we report updates on IDFS and DDFS with additional follow-up, as well as distantrecurrence-free interval (DRFI) and post hoc analyses in premenopausal women.Methods: Eligibilitycriteria included women &gt; 18 years of age with HR+, HER2-BC and 1-3 +LN and no contraindications to taxane and/or anthracycline basedCT. DRFI was defined as time to distant recurrence or death from breast cancer.Analyses were intent-to-treat among eligible pts. We performed a post hocanalysis evaluating IDFS between treatment arms in premenopausal pts with pN1mi.In addition, we conducted a two-year landmarked IDFS analysis by ovarianfunction suppression (OFS) or not in the ET arm, as well as by regularmenstrual periods or not in both treatment arms.Results: Among the 4,984eligible pts, there were 553 IDFS events and median follow-up of 6.1 years.Postmenopausal women do not have any IDFS or DDFS benefit with CT; however, 5-yearabsolute benefits for IDFS and DDFS with CT for premenopausal pts were 5.9% and3.3%, respectively. In pre-menopausal pts, CT was associated with improved DRFIfor all RS values &lt; 25, with an absolute improvement of 2.3% for RS0-13 and of 2.8% for RS 14-25. Among premenopausal pts, 12.4% (n=206) had pNmi)disease. In a post hoc analysis, there was a trend for CT benefit for thosewith pNmi [hazard ratio (HR)=0.44, confidence interval (CI)=0.18-1.08]. Therewere only 22 IDFS events. Only 17.2% of premenopausal pts assigned to ETunderwent OFS in the first 24 months and in two-year landmarked analysis, therewas no IDFS difference in those who underwent OFS or not (HR=0.88,CI=0.47-1.63). In premenopausal women assigned to ET, 58.9% stopped havingperiods within the first 24 months, and have anumerically improved IDFS compared to those who continued regular periods (HR=1.48,CI: 0.92-2.40). Among premenopausal assigned to CT followed by ET, 80.8%stopped having periods within the first 24 months and have a numericallyimproved IDFS compared to those who continue to have regular periods (HR=1.56, CI:0.85-2.86).Discussion: In accordancewith the differential IDFS and DDFS benefit based upon menopausal status inS1007, premenopausal pts with 1-3+LN and RS &lt; 25 had a statisticallysignificant improvement in DRFI with the addition of CT. A small proportion of S1007premenopausal participants underwent OFS. The role of OFS as it relates to CTbenefit cannot be determined from this study. A future randomized trial should address the clinical question if OFScan replace CT in premenopausal pts with HR+/HER2-, node-positive breast cancer.Funding: Supported by National Cancer Institute grants U10CA180888, U10CA180819,U10CA180820, U10CA180821, U10CA180868, U10CA180863, and in part by Susan G.Komen for the Cure® Research Program, The Hope Foundation for Cancer Research,Breast Cancer Research Foundation, and Genomic Health, Inc.

Citation Format: Kevin M Kalinsky, William E Barlow, Julie R Gralow, Funda Meric-Bernstam, Kathy S Albain, Daniel F Hayes, Nancy U Lin, Edith A Perez, Lori A Goldstein, Stephen KL Chia, Sukhbinder Dhesy-Thind, Priya Rastogi, Emilio Alba, Suzette Delaloge, Miguel Martin, Catherine M Kelly, Manuel Ruiz-Borrego, Miguel Gil-Gil, Claudia H Arce-Salinas, Etienne GC Brain, Eun Sook Lee, Jean-Yves Pierga, Begoña Bermejo, Manuel Ramos-Vasquez, Kyung Hae Jung, Jean-Marc Ferrero, Anne Schott, Steven Shak, Priyanka Sharma, Danika Lew, Jieling Miao, Debasish Tripathy, Lajos Pusztai, Gabriel Hortobagyi. Updated results from a phase 3 randomized clinical trial in participants (pts) with 1-3 positive lymph nodes (LN), hormone receptor-positive (HR+) and HER2-negative (HER2-) breast cancer (BC) with recurrence score (RS) ≤ 25 randomized to endocrine therapy (ET) +/- chemotherapy (CT): SWOG S1007 (RxPONDER) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr GS2-07.

Abstract GS3-05: Fulvestrant-palbociclib vs continuing aromatase inhibitor-palbociclib upon detection of circulating ESR1 mutation in HR+ HER2- metastatic breast cancer patients: Results of PADA-1, a UCBG-GINECO randomized phase 3 trial

Background: ESR1 mutations are known drivers of resistance to first line aromatase inhibitors (AI)-based therapy in hormone receptor-positive (HR+) HER2- metastatic breast cancer (mBC) patients (pts), but their clinical actionability remains unknown. The randomized phase 3 PADA-1 trial aimed at evaluating the clinical benefit associated with a switch to fulvestrant-palbociclib upon the detection of a rising ESR1 mutation in blood (bESR1mut) in HR+ HER2- mBC pts treated by first line AI-palbociclib.. Methods: PADA-1 (NCT03079011), a multicenter, randomized, open-label, phase 3 trial, enrolled HR+ HER2- mBC pts with no prior therapy for mBC in the absence of AI-resistance. In the first step, pts were treated with AI-palbociclib as first line therapy and underwent centralized bESR1mut screening every two months. Rising bESR1mut+ pts with no clinical/imaging concomitant disease progression were included in the second step, in which they were randomized between continuing the same therapy (standard arm) or switching to fulvestrant-palbociclib (experimental arm). The third step consisted in an optional crossover to fulvestrant-palbociclib following tumor progression for patients randomized in the standard arm. PADA-1 co-primary endpoints were PFS in the second step, and global safety.. Results: Between 03/2017 and 01/2019, 1,017 pts have been included in the first step. After a median time of 15.6 months in the first step, 172 pts with rising bESR1mut and no synchronous disease progression were randomized to continuing AI-palbociclib (N=84 pts) or to fulvestrant-palbociclib (N=88 pts). Among the 172 randomized pts, N=136 PFS events have been observed in the second step after a median follow-up of 26 months. The median PFS was 5.7 months (95%CI[3.9;7.5]) in the AI-palbociclib arm and 11.9 months (95%CI[9.1;13.6]) in the fulvestrant-palbociclib arm (HR=0.63; 95%CI|0.45-0.88], p=0.007). Among the 70 patients who subsequently developed a disease progression in the AI-palbociclib arm, 47 were included in the optional crossover cohort. With a median follow-up of 14.7 months and 37 events, the median second-PFS observed in the cross-over cohort was 3.5 months (95%CI [2.7-5.1]). Treatment safety and validation of the ESR1mut assay are reported separately (poster session #1). Conclusion: PADA-1 reached its primary objective. This first-of-its-kind liquid biopsy-based trial demonstrates that targeting bESR1mut-associated resistance through a change in the endocrine partner of palbociclib is feasible and allows a doubling in the subsequent median progression free survival.. Funding: Pfizer

Citation Format: François-Clément Bidard, Anne-Claire Hardy-Bessard, Thomas Bachelot, Jean-Yves Pierga, Jean-Luc Canon, Florian Clatot, Fabrice Andre, Thibault De La Motte Rouge, Barbara Pistilli, Florence Dalenc, Nadine Dohollou, Olivier Arsene, Thierry Petit, Cécilia Riedl, François Morvan, Adina Marti, Emma Lachaier, Mihaela Achille, Michel Gozy, Anne Escande, Dominique Mille, Fanny Trouboul, Laurent Arnould, Ivan Bieche, Anne Pradines, Jerome Lemonnier, Frederique Berger, Suzette Delaloge. Fulvestrant-palbociclib vs continuing aromatase inhibitor-palbociclib upon detection of circulating ESR1 mutation in HR+ HER2- metastatic breast cancer patients: Results of PADA-1, a UCBG-GINECO randomized phase 3 trial [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr GS3-05.

Abstract P1-18-16: First line aromatase inhibitor (AI) + palbociclib with randomized switch to fulvestrant + palbociclib upon detection of circulating ESR1 mutation in HR+ HER2- metastatic breast cancer patients: Global safety results of PADA-1, a UCBG-GINECO phase III trial

Background: Aromatase inhibitors (AI) in combination with a CDK 4/6 inhibitor have been established as the standard first line treatment of non AI-resistant hormone receptor-positive (HR+) HER2- metastatic breast cancer (mBC) patients (pts). ESR1 mutations are known drivers of resistance to AIs in the metastatic setting but their actionability remains unknown. The phase 3 PADA-1 trial aimed both at refining the global safety of palbociclib combined to any AI as first line treatment of HR+ HER2- mBC pts, and at evaluating the clinical benefit associated with a switch to fulvestrant-palbociclib upon detection of a rising ESR1 mutation in blood (bESR1mut). Methods: PADA-1 (NCT03079011), a multicenter, randomized, open-label, phase 3 trial, enrolled HR+ HER2- mBC pts with no prior therapy for mBC, in the absence of AI-resistance. In the first step, pts received a combination of any AI and palbociclib at standard recommended doses and underwent centralized bESR1mut screening every two months. In the second step, bESR1mut+ pts with no clinical/imaging concomitant disease progression were randomized between continuing the same therapy (standard arm) or switching to fulvestrant-palbociclib (experimental arm). The third step consisted in an optional cross-over after tumor progression for patients randomized in the standard arm. PADA-1 co-primary endpoints were global safety of the combination of palbociclib + endocrine therapy in the whole population of patients, throughout the study, with focus on hematological toxicities; and PFS in the second step. We present here the results of the global safety co-primary endpoint. Results: From 3/2017 to 01/2019, 1017 pts were accrued in 83 sites. As per 05/2021, 272 pts were still in step 1, 35 in step 2, and 8 in step 3. The overall follow-up was 33.7 months. 232 pts have deceased. 333 SAEs have been reported, including 21 grade 5, 35 grade 4, 183 grade 3, 53 grade 2, 26 grade 1 and 15 unknown grade. Among the grade 5 cases, 2 have been declared as potentially related to the underlying treatment (Death of unknown cause, pulmonary embolism). No pt died of SARS-CoV2 infection. The main hematological toxicities encountered, as well as selected non-hematological events are described in Table 1. Permanent discontinuation of the treatment due to toxicity occurred in 39 pts/1017 (3.8%). Palbociclib dose decreases occurred in 419 (41.2%) pts. Conclusion: By the number of included patients, PADA-1 is the largest prospective trial with 1st line AI and palbociclib. Data confirm the favorable safety profile of palbociclib when combined to any AI +/- switch to fulvestrant. Hematological toxicity appears limited and is mostly restricted to non-clinically significant neutropenia. Permanent discontinuation was exceptional. Detailed per-step analyses will be presented.

Table 1.Adverse events (% pts)Grade 3, N (%)Grade 4, N (%)Neutropenia628 (61.8%)83 (8.2%)Febrile neutropenia4 (0.4%)0Thrombocytopenia18 (1.8%)3 (0.3%)Anemia24 (2.4%)0Lymphocytopenia58 (5.7%)5 (0.5%)Insterstitial lung disease4 (0.4%)0Liver enzymes increase (AST/ALT)5 (0.5%)0Mucositis10 (1%)0

Citation Format: Suzette Delaloge, Anne-Claire Hardy-Bessard, Thomas Bachelot, Jean-Yves Pierga, Jean-Luc Canon, Florian Clatot, Fabrice André, Thibault De La Motte Rouge, Barbara Pistilli, Florence Dalenc, Nadine Dohollou, Olivier Arsene, Thierry Petit, Cecilia Riedl, François Morvan, Adina Marti, Emma Lachaier, Mihaela Achille, Michel Gozy, Anne Escande, Dominique Mille, Fanny Trouboul, Sandrine Marques, Jerome Lemonnier, Frederique Berger, François-Clément Bidard. First line aromatase inhibitor (AI) + palbociclib with randomized switch to fulvestrant + palbociclib upon detection of circulating ESR1 mutation in HR+ HER2- metastatic breast cancer patients: Global safety results of PADA-1, a UCBG-GINECO phase III trial [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-18-16.

Helping Patients Communicate With Oncologists When Cancer Treatment Resistance Occurs to Develop, Test, and Implement a Patient Communication Aid: Sequential Collaborative Mixed Methods Study

BACKGROUND

Most cancer-related deaths result from disseminated diseases that develop resistance to anticancer treatments. Inappropriate communication in this challenging situation may result in unmet patient information and support needs. Patient communication aids such as question prompt lists (QPLs) may help.

OBJECTIVE

This study aims to develop and pilot-test a specific QPL in the following two contrasting clinical contexts in France after cancer resistance has developed: triple-negative and luminal B metastatic breast cancer (MBC) and metastatic uveal melanoma (MUM).

METHODS

A sequential study design with a mixed methods collaborative approach will be applied. The first step aims to build a specific QPL. Step 1a will explore oncologist-patient communication issues from oncology professionals' interviews (n=20 approximately). Step 1b will appraise information and support needs experienced by patients with MBC or MUM both quantitatively (n=80) and qualitatively (n=40 approximately). These data will be used to develop and pilot-test a QPL specific to patients with cancer experiencing initial or acquired resistance to treatment. We expect to obtain a core QPL that comprises questions and concerns commonly expressed by patients with resistant cancer and is complemented by specific issues for either MBC or MUM cancer sites. In step 1c, 2 focus groups of patients with any type of metastatic cancer (n=4) and health care professionals (n=4) will be conducted to revise the content of a preliminary QPL and elaborate an acceptable and feasible clinical implementation. In step 1d, the content of the QPL version 1 and implementation guidance will be validated using a Delphi process. Step 2 will pilot-test the QPL version 1 in real practice with patients with MBC or MUM (n=80). Clinical utility will be assessed by comparing responses to questionnaires administered in step 1b (QPL-naive historical control group) and step 2 (QPL intervention group).

RESULTS

This study received grants in March and December 2019 and was approved by the French national ethics committee in July 2019. As of October 2021, interviews with oncology professionals have been conducted and analyzed (N=26 to reach saturation), and 39 and 27 patients with MBC and MUM, respectively, have been recruited.

CONCLUSIONS

A clinically and culturally tailored QPL is expected to facilitate patients' participation in consultations, improve oncologists' responses to patients' information and support needs, and thus foster patients' psychological adjustment to the diagnosis and follow-up of cancer resistance to treatment.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04118062; http://clinicaltrials.gov/ct2/show/NCT04118062.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/26414.

21-Gene Assay to Inform Chemotherapy Benefit in Node-Positive Breast Cancer

BACKGROUND

The recurrence score based on the 21-gene breast-cancer assay has been clinically useful in predicting a chemotherapy benefit in hormone-receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative, axillary lymph-node-negative breast cancer. In women with positive lymph-node disease, the role of the recurrence score with respect to predicting a benefit of adjuvant chemotherapy is unclear.

METHODS

In a prospective trial, we randomly assigned women with hormone-receptor-positive, HER2-negative breast cancer, one to three positive axillary lymph nodes, and a recurrence score of 25 or lower (scores range from 0 to 100, with higher scores indicating a worse prognosis) to endocrine therapy only or to chemotherapy plus endocrine (chemoendocrine) therapy. The primary objective was to determine the effect of chemotherapy on invasive disease-free survival and whether the effect was influenced by the recurrence score. Secondary end points included distant relapse-free survival.

RESULTS

A total of 5083 women (33.2% premenopausal and 66.8% postmenopausal) underwent randomization, and 5018 participated in the trial. At the prespecified third interim analysis, the chemotherapy benefit with respect to increasing invasive disease-free survival differed according to menopausal status (P = 0.008 for the comparison of chemotherapy benefit in premenopausal and postmenopausal participants), and separate prespecified analyses were conducted. Among postmenopausal women, invasive disease-free survival at 5 years was 91.9% in the endocrine-only group and 91.3% in the chemoendocrine group, with no chemotherapy benefit (hazard ratio for invasive disease recurrence, new primary cancer [breast cancer or another type], or death, 1.02; 95% confidence interval [CI], 0.82 to 1.26; P = 0.89). Among premenopausal women, invasive disease-free survival at 5 years was 89.0% with endocrine-only therapy and 93.9% with chemoendocrine therapy (hazard ratio, 0.60; 95% CI, 0.43 to 0.83; P = 0.002), with a similar increase in distant relapse-free survival (hazard ratio, 0.58; 95% CI, 0.39 to 0.87; P = 0.009). The relative chemotherapy benefit did not increase as the recurrence score increased.

CONCLUSIONS

Among premenopausal women with one to three positive lymph nodes and a recurrence score of 25 or lower, those who received chemoendocrine therapy had longer invasive disease-free survival and distant relapse-free survival than those who received endocrine-only therapy, whereas postmenopausal women with similar characteristics did not benefit from adjuvant chemotherapy. (Funded by the National Cancer Institute and others; RxPONDER ClinicalTrials.gov number, NCT01272037.).

Multicenter evaluation of breast cancer patients' satisfaction and experience with oncology telemedicine visits during the COVID-19 pandemic

INTRODUCTION

During the COVID-19 pandemic, teleconsultation was implemented in clinical practice to limit patient exposure to COVID-19 while monitoring their treatment and follow-up. We sought to examine the satisfaction of patients with breast cancer (BC) who underwent teleconsultations during this period.

METHODS

Eighteen centres in France and Italy invited patients with BC who had at least one teleconsultation during the first wave of the COVID-19 pandemic to participate in a web-based survey that evaluated their satisfaction (EORTC OUT-PATSAT 35 and Telemedicine Satisfaction Questionnaire [TSQ] scores) with teleconsultation.

RESULTS

Among the 1299 participants eligible for this analysis, 53% of participants were undergoing standard post-treatment follow-up while 22 and 17% were currently receiving active anticancer therapy for metastatic and localised cancers, respectively. The mean satisfaction scores were 77.4 and 73.3 for the EORTC OUT-PATSAT 35 and TSQ scores, respectively. In all, 52.6% of participants had low/no anxiety. Multivariable analysis showed that the EORTC OUT-PATSAT 35 score correlated to age, anxiety score and teleconsultation modality. The TSQ score correlated to disease status and anxiety score.

CONCLUSION

Patients with BC were satisfied with oncology teleconsultations during the COVID-19 pandemic. Teleconsultation may be an acceptable alternative follow-up modality in specific circumstances.

Factors Associated With the Discussion of Fertility Preservation in a Cohort of 1,357 Young Breast Cancer Patients Receiving Chemotherapy

PURPOSE

Female breast cancer (BC) patients exposed to gonadotoxic chemotherapy are at risk of future infertility. There is evidence of disparities in the discussion of fertility preservation for these patients. The aim of the study was to identify factors influencing the discussion of fertility preservation (FP).

MATERIAL AND METHODS

We analyzed consecutive BC patients treated by chemotherapy at Institut Curie from 2011-2017 and aged 18-43 years at BC diagnosis. The discussion of FP was classified in a binary manner (discussion/no discussion), based on mentions present in the patient's electronic health record (EHR) before the initiation of chemotherapy. The associations between FP discussion and the characteristics of patients/tumors and healthcare practitioners were investigated by logistic regression analysis.

RESULTS

The median age of the 1357 patients included in the cohort was 38.7 years, and median tumor size was 30.3 mm. The distribution of BC subtypes was as follows: 702 luminal BCs (58%), 241 triple-negative breast cancers (TNBCs) (20%), 193 HER2+/HR+ (16%) and 81 HER2+/HR- (6%). All patients received chemotherapy in a neoadjuvant (n=611, 45%) or adjuvant (n= 744, 55%) setting. A discussion of FP was mentioned for 447 patients (33%). Earlier age at diagnosis (discussion: 34.4 years versus no discussion: 40.5 years), nulliparity (discussion: 62% versus no discussion: 38%), and year of BC diagnosis were the patient characteristics significantly associated with the mention of FP discussion. Surgeons and female physicians were the most likely to mention FP during the consultation before the initiation of chemotherapy (discussion: 22% and 21%, respectively). The likelihood of FP discussion increased significantly over time, from 15% in 2011 to 45% in 2017. After multivariate analysis, FP discussion was significantly associated with younger age, number of children before BC diagnosis, physicians' gender and physicians' specialty.

CONCLUSION

FP discussion rates are low and are influenced by patient and physician characteristics. There is therefore room for improvement in the promotion and systematization of FP discussion.

Multimodal liquid biopsy for early monitoring and outcome prediction of chemotherapy in metastatic breast cancer

Circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) are two cancer-derived blood biomarkers that inform on patient prognosis and treatment efficacy in breast cancer. We prospectively evaluated the clinical validity of quantifying both CTCs (CellSearch) and ctDNA (targeted next-generation sequencing). Their combined value as prognostic and early monitoring markers was assessed in 198 HER2-negative metastatic breast cancer patients. All patients were included in the prospective multicenter UCBG study COMET (NCT01745757) and treated by first-line chemotherapy with weekly paclitaxel and bevacizumab. Blood samples were obtained at baseline and before the second cycle of chemotherapy. At baseline, CTCs and ctDNA were respectively detected in 72 and 74% of patients and were moderately correlated (Kendall’s τ = 0.3). Only 26 (13%) patients had neither detectable ctDNA nor CTCs. Variants were most frequently observed in TP53 and PIK3CA genes. KMT2C/MLL3 variants detected in ctDNA were significantly associated with a lower CTC count, while the opposite trend was seen with GATA3 alterations. Both CTC and ctDNA levels at baseline and after four weeks of treatment were correlated with survival. For progression-free and overall survival, the best multivariate prognostic model included tumor subtype (triple negative vs other), grade (grade 3 vs other), ctDNA variant allele frequency (VAF) at baseline (per 10% increase), and CTC count at four weeks (≥5CTC/7.5 mL). Overall, this study demonstrates that CTCs and ctDNA have nonoverlapping detection profiles and complementary prognostic values in metastatic breast cancer patients. A comprehensive liquid-biopsy approach may involve simultaneous detection of ctDNA and CTCs.

A DNA methylation-based liquid biopsy for triple-negative breast cancer

Here, we present a next-generation sequencing (NGS) methylation-based blood test called methylation DETEction of Circulating Tumour DNA (mDETECT) designed for the optimal detection and monitoring of metastatic triple-negative breast cancer (TNBC). Based on a highly multiplexed targeted sequencing approach, this assay incorporates features that offer superior performance and included 53 amplicons from 47 regions. Analysis of a previously characterised cohort of women with metastatic TNBC with limited quantities of plasma (<2 ml) produced an AUC of 0.92 for detection of a tumour with a sensitivity of 76% for a specificity of 100%. mDETECT_TNBC was quantitative and showed superior performance to an NGS TP53 mutation-based test carried out on the same patients and to the conventional CA15-3 biomarker. mDETECT also functioned well in serum samples from metastatic TNBC patients where it produced an AUC of 0.97 for detection of a tumour with a sensitivity of 93% for a specificity of 100%. An assay for BRCA1 promoter methylation was also incorporated into the mDETECT assay and functioned well but its clinical significance is currently unclear. Clonal Hematopoiesis of Indeterminate Potential was investigated as a source of background in control subjects but was not seen to be significant, though a link to adiposity may be relevant. The mDETECT_TNBC assay is a liquid biopsy able to quantitatively detect all TNBC cancers and has the potential to improve the management of patients with this disease.

Breast Cancer (BC) Is a Window of Opportunity for Smoking Cessation: Results of a Retrospective Analysis of 1234 BC Survivors in Follow-Up Consultation

Breast cancer (BC) is the most commonly diagnosed type of cancer and the leading cause of cancer deaths in women. Smoking is the principal modifiable risk factor for cancers and has a negative influence on long-term survival. We conducted a retrospective study on consecutive BC survivors seen at follow-up consultations between 3 June and 30 October 2019 at Institut Curie, Paris, France. Smoking behaviors were evaluated prospectively via interviewer-administered questionnaires. The aim of this study was to describe smoking-related patient care at diagnosis and smoking cessation patterns in women with a history of BC. A total of 1234 patients were included in the study. Smoking status at diagnosis was missing from electronic health records in 32% of cases, including 13% of patients who smoke. Only 20% of the 197 patients currently smoking at diagnosis recalled having a discussion about smoking with a healthcare professional. Radiotherapists and surgeons were more likely to talk about complications than other practitioners. The main type of information provided was general advice to stop smoking (n = 110), followed by treatment complications (n = 48), while only five patients were referred to tobaccologists. Since diagnosis, 33% (n = 65) of the patients currently smoking had quit. Patients who quit had a lower alcohol consumption, but no other factor was associated with smoking cessation. The main motivation for tobacco withdrawal was the fear of BC relapse (63%). This study highlights room for improvement in the assessment of smoking behavior. Our data raise important perspectives for considering BC treatment and follow-up as a window of opportunity for smoking cessation.

Serial Analysis of Circulating Tumor Cells in Metastatic Breast Cancer Receiving First-Line Chemotherapy

BACKGROUND

We examined the prognostic significance of circulating tumor cell (CTC) dynamics during treatment in metastatic breast cancer (MBC) patients receiving first-line chemotherapy.

METHODS

Serial CTC data from 469 patients (2202 samples) were used to build a novel latent mixture model to identify groups with similar CTC trajectory (tCTC) patterns during the course of treatment. Cox regression was used to estimate hazard ratios for progression-free survival (PFS) and overall survival (OS) in groups based on baseline CTCs, combined CTC status at baseline to the end of cycle 1, and tCTC. Akaike information criterion was used to select the model that best predicted PFS and OS.

RESULTS

Latent mixture modeling revealed 4 distinct tCTC patterns: undetectable CTCs (56.9% ), low (23.7%), intermediate (14.5%), or high (4.9%). Patients with low, intermediate, and high tCTC patterns had statistically significant inferior PFS and OS compared with those with undetectable CTCs (P < .001). Akaike Information Criterion indicated that the tCTC model best predicted PFS and OS compared with baseline CTCs and combined CTC status at baseline to the end of cycle 1 models. Validation studies in an independent cohort of 1856 MBC patients confirmed these findings. Further validation using only a single pretreatment CTC measurement confirmed prognostic performance of the tCTC model.

CONCLUSIONS

We identified 4 novel prognostic groups in MBC based on similarities in tCTC patterns during chemotherapy. Prognostic groups included patients with very poor outcome (intermediate + high CTCs, 19.4%) who could benefit from more effective treatment. Our novel prognostic classification approach may be used for fine-tuning of CTC-based risk stratification strategies to guide future prospective clinical trials in MBC.

70-gene signature as an aid for treatment decisions in early breast cancer: updated results of the phase 3 randomised MINDACT trial with an exploratory analysis by age

BACKGROUND

The MINDACT trial showed excellent 5-year distant metastasis-free survival of 94·7% (95% CI 92·5-96·2) in patients with breast cancer of high clinical and low genomic risk who did not receive chemotherapy. We present long-term follow-up results together with an exploratory analysis by age.

METHODS

MINDACT was a multicentre, randomised, phase 3 trial done in 112 academic and community hospitals in nine European countries. Patients aged 18-70 years, with histologically confirmed primary invasive breast cancer (stage T1, T2, or operable T3) with up to three positive lymph nodes, no distant metastases, and a WHO performance status of 0-1 were enrolled and their genomic risk (using the MammaPrint 70-gene signature) and clinical risk (using a modified version of Adjuvant! Online) were determined. Patients with low clinical and low genomic risk results did not receive chemotherapy, and patients with high clinical and high genomic risk did receive chemotherapy (mostly anthracycline-based or taxane-based, or a combination thereof). Patients with discordant risk results (ie, patients with high clinical risk but low genomic risk, and those with low clinical risk but high genomic risk) were randomly assigned (1:1) to receive chemotherapy or not based on either the clinical risk or the genomic risk. Randomisation was done centrally and used a minimisation technique that was stratified by institution, risk group, and clinical-pathological characteristics. Treatment allocation was not masked. The primary endpoint was to test whether the distant metastasis-free survival rate at 5 years in patients with high clinical risk and low genomic risk not receiving chemotherapy had a lower boundary of the 95% CI above the predefined non-inferiority boundary of 92%. In the primary test population of patients with high clinical risk and low genomic risk who adhered to the treatment allocation of no chemotherapy and had no change in risk post-enrolment. Here, we present updated follow-up as well as an exploratory analysis of a potential age effect (≤50 years vs >50 years) and an analysis by nodal status for patients with hormone receptor-positive and HER2-negative disease. These analyses were done in the intention-to-treat population. This study is registered with ClinicalTrials.gov, NCT00433589, and the European Clinical Trials database, EudraCT2005-002625-31. Recruitment is complete and further long-term follow-up is ongoing.

FINDINGS

Between Feb 8, 2007, and July 11, 2011, 6693 patients were enrolled. On Feb 26, 2020, median follow-up was 8·7 years (IQR 7·8-9·7). The updated 5-year distant metastasis-free survival rate for patients with high clinical risk and low genomic risk receiving no chemotherapy (primary test population, n=644) was 95·1% (95% CI 93·1-96·6), which is above the predefined non-inferiority boundary of 92%, supporting the previous analysis and proving MINDACT as a positive de-escalation trial. Patients with high clinical risk and low genomic risk were randomly assigned to receive chemotherapy (n=749) or not (n=748); this was the intention-to-treat population. The 8-year estimates for distant metastasis-free survival in the intention-to-treat population were 92·0% (95% CI 89·6-93·8) for chemotherapy versus 89·4% (86·8-91·5) for no chemotherapy (hazard ratio 0·66; 95% CI 0·48-0·92). An exploratory analysis confined to the subset of patients with hormone receptor-positive, HER2-negative disease (1358 [90.7%] of 1497 randomly assigned patients, of whom 676 received chemotherapy and 682 did not) shows different effects of chemotherapy administration on 8-year distant metastasis-free survival according to age: 93·6% (95% CI 89·3-96·3) with chemotherapy versus 88·6% (83·5-92·3) without chemotherapy in 464 women aged 50 years or younger (absolute difference 5·0 percentage points [SE 2·8, 95% CI -0·5 to 10·4]) and 90·2% (86·8-92·7) versus 90·0% (86·6-92·6) in 894 women older than 50 years (absolute difference 0·2 percentage points [2·1, -4·0 to 4·4]). The 8-year distant metastasis-free survival in the exploratory analysis by nodal status in these patients was 91·7% (95% CI 88·1-94·3) with chemotherapy and 89·2% (85·2-92·2) without chemotherapy in 699 node-negative patients (absolute difference 2·5 percentage points [SE 2·3, 95% CI -2·1 to 7·2]) and 91·2% (87·2-94·0) versus 89·9% (85·8-92·8) for 658 patients with one to three positive nodes (absolute difference 1·3 percentage points [2·4, -3·5 to 6·1]).

INTERPRETATION

With a more mature follow-up approaching 9 years, the 70-gene signature shows an intact ability of identifying among women with high clinical risk, a subgroup, namely patients with a low genomic risk, with an excellent distant metastasis-free survival when treated with endocrine therapy alone. For these women the magnitude of the benefit from adding chemotherapy to endocrine therapy remains small (2·6 percentage points) and is not enhanced by nodal positivity. However, in an underpowered exploratory analysis this benefit appears to be age-dependent, as it is only seen in women younger than 50 years where it reaches a clinically relevant threshold of 5 percentage points. Although, possibly due to chemotherapy-induced ovarian function suppression, it should be part of informed, shared decision making. Further study is needed in younger women, who might need reinforced endocrine therapy to forego chemotherapy.

FUNDING

European Commission Sixth Framework Programme.

Circulating tumor DNA as a dynamic biomarker of response to palbociclib and fulvestrant in metastatic breast cancer patients

Background

Following the PALOMA-3 study results, the combination of palbociclib, a CDK4/6 inhibitor, with fulvestrant, a selective estrogen receptor degrader, has become a standard therapy in women with estrogen receptor-positive (ER+) HER2-negative (HER2−) metastatic breast cancer (MBC). Palbociclib has been shown to increase the progression-free survival (PFS) overall but no predictive biomarker of palbociclib efficacy has been validated so far. We thus evaluated whether early changes of circulating tumor DNA (ctDNA) levels are associated with palbociclib plus fulvestrant efficiency.

Methods

ER+ HER2− MBC patients were included in a prospective observational cohort before treatment initiation. Tumor response was assessed by radiological evaluation (RECIST v1.1) every 3 months. Plasma samples were collected before treatment (baseline), at day 15 (D15), at day 30 (D30), and at disease progression. We searched for somatic mutations from archived tumor tissues by targeted deep sequencing. For patients with somatic mutations identified, circulating tumor DNA (ctDNA) was tracked using digital droplet PCR. Ratios of ctDNA levels ([D15/baseline] and [D30/baseline]) were then correlated with prospectively registered patient characteristics and outcomes.

Results

Twenty-five of the 61 patients enrolled had a somatic mutation testable in plasma (N_PIK3CA = 21, N_TP53 = 2, N_AKT1 = 2). At baseline, 84% of patients had detectable ctDNA levels but ctDNA levels had no prognostic impact on PFS (p = 0.10). Among those patients, ctDNA was still detected in 82% at D15 and 68% at D30. ctDNA clearance observed at day 30 was associated with longer PFS (HR = 7.2, 95% CI = 1.5–32.6, p = 0.004). On the contrary, a [D30/baseline] ctDNA ratio > 1 was associated with a shorter PFS (HR = 5.1, 95% CI = 1.4–18.3, p = 0.02) and all 5 patients with increased ctDNA levels at D30 showed disease progression after 3 months under palbociclib-fulvestrant. Finally, at the time of radiological tumor progression, ctDNA was detected in all patients tested.

Conclusion

Our study demonstrates that the efficiency of palbociclib and fulvestrant can be monitored by serial analyses of ctDNA before radiological evaluation and that early ctDNA variation is a prognostic factor of PFS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-021-01411-0.

Neoadjuvant Endocrine Therapy in Breast Cancer Management: State of the Art

Simple Summary

Over the last ten years, neoadjuvant endocrine therapy (NET) has been increasingly investigated and has gained recognition. NET should not only be used to allow surgery or to improve breast-conserving surgery rates in patients not eligible for NCT, but also as a research tool for the search for endocrine sensitivity biomarkers and targeted therapies, and for prognostic information in ER+/HER2-.

Abstract

Endocrine therapy is the mainstay of treatment in HR+/HER2- breast cancers, which represent about 70% of all breast cancers. Neoadjuvant therapy has been developed since the 1990s to address several issues, including breast-conserving surgery (BCS) and improvement of survival rates. For a long time, neoadjuvant endocrine therapy (NET) was confined to frail patients in order to improve surgery outcome. Since the 2000s, NET now plays a central role as a research tool for predictive endocrine sensitivity biomarkers and targeted therapies. One of the major issues in early HR+/HER2- breast cancer is to identify patients in whom chemotherapy can be safely withheld. In vivo assessment of response to NET might be the best treatment strategy to address this issue.