Prognostic value of EndoPredict test in patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative primary breast cancer screened for the randomized, double-blind, phase III UNIRAD trial

BACKGROUND

The purpose of this study was to evaluate the prognostic value of the multigene EndoPredict test in prospectively collected data of patients screened for the randomized, double-blind, phase III UNIRAD trial, which evaluated the addition of everolimus to adjuvant endocrine therapy in high-risk, hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative early breast cancer.

PATIENTS AND METHODS

Patients were classified into low or high risk according to the EPclin score, consisting of a 12-gene molecular score combined with tumor size and nodal status. Association of the EPclin score with disease-free survival (DFS) and distant metastasis-free survival (DMFS) was evaluated using Kaplan-Meier estimates. The independent prognostic added value of EPclin score was tested in a multivariate Cox model after adjusting on tumor characteristics.

RESULTS

EndoPredict test results were available for 768 patients: 663 patients classified as EPclin high risk (EPCH) and 105 patients as EPclin low risk (EPCL). Median follow-up was 70 months (range 1-172 months). For the 429 EPCH randomized patients, there was no significant difference in DFS between treatment arms. The 60-month relapse rate for patients in the EPCL and EPCH groups was 0% and 7%, respectively. Hazard ratio (HR) supposing continuous EPclin score was 1.87 [95% confidence interval (CI) 1.4-2.5, P < 0.0001]. This prognostic effect remained significant when assessed in a Cox model adjusting on tumor size, number of positive nodes and tumor grade (HR 1.52, 95% CI 1.09-2.13, P = 0.0141). The 60-month DMFS for patients in the EPCL and EPCH groups was 100% and 94%, respectively (adjusted HR 8.10, 95% CI 1.1-59.1, P < 0.0001).

CONCLUSIONS

The results confirm the value of EPclin score as an independent prognostic parameter in node-positive, hormone receptor-positive, HER2-negative early breast cancer patients receiving standard adjuvant treatment. EPclin score can be used to identify patients at higher risk of recurrence who may warrant additional systemic treatments.

Bias reduction using combined stain normalization and augmentation for AI-based classification of histological images

Artificial intelligence (AI)-assisted diagnosis is an ongoing revolution in pathology. However, a frequent drawback of AI models is their propension to make decisions based rather on bias in training dataset than on concrete biological features, thus weakening pathologists' trust in these tools. Technically, it is well known that microscopic images are altered by tissue processing and staining procedures, being one of the main sources of bias in machine learning for digital pathology. So as to deal with it, many teams have written about color normalization and augmentation methods. However, only a few of them have monitored their effects on bias reduction and model generalizability. In our study, two methods for stain augmentation (AugmentHE) and fast normalization (HEnorm) have been created and their effect on bias reduction has been monitored. Actually, they have also been compared to previously described strategies. To that end, a multicenter dataset created for breast cancer histological grading has been used. Thanks to it, classification models have been trained in a single center before assessing its performance in other centers images. This setting led to extensively monitor bias reduction while providing accurate insight of both augmentation and normalization methods. AugmentHE provided an 81% increase in color dispersion compared to geometric augmentations only. In addition, every classification model that involved AugmentHE presented a significant increase in the area under receiving operator characteristic curve (AUC) over the widely used RGB shift. More precisely, AugmentHE-based models showed at least 0.14 AUC increase over RGB shift-based models. Regarding normalization, HEnorm appeared to be up to 78x faster than conventional methods. It also provided satisfying results in terms of bias reduction. Altogether, our pipeline composed of AugmentHE and HEnorm improved AUC on biased data by up to 21.7% compared to usual augmentations. Conventional normalization methods coupled with AugmentHE yielded similar results while being much slower. In conclusion, we have validated an open-source tool that can be used in any deep learning-based digital pathology project on H&E whole slide images (WSI) that efficiently reduces stain-induced bias and later on might help increase pathologists' confidence when using AI-based products.

Pertuzumab Plus Trastuzumab With or Without Chemotherapy Followed by Emtansine in ERBB2-Positive Metastatic Breast Cancer: A Secondary Analysis of a Randomized Clinical Trial

Importance

In ERBB2 (formerly HER2)-positive metastatic breast cancer (MBC), combining trastuzumab and pertuzumab with taxane-based chemotherapy is the first line of standard care. Given that trastuzumab plus pertuzumab was proven effective in ERBB2-positive MBC, even without chemotherapy, whether the optimal first-line strategy could be trastuzumab plus pertuzumab alone instead of with chemotherapy is unresolved.

Objective

To assess overall survival (OS) at 2 years and progression-free survival (PFS) for patients randomly assigned to receive first-line pertuzumab plus trastuzumab alone or with chemotherapy followed by trastuzumab and emtansine at progression; PFS of second-line trastuzumab and emtansine treatment following trastuzumab plus pertuzumab; and OS and PFS in the ERBB2-enriched and ERBB2-nonenriched subtypes.

Design, Setting, and Participants

This was a secondary analysis of a multicenter, open-label, phase 2 randomized clinical trial conducted at 27 sites in France, 20 sites in Switzerland, 9 sites in the Netherlands, and 1 site in Germany. Overall, 210 patients with centrally confirmed ERBB2-positive MBC were randomized between May 3, 2013, and January 4, 2016, with termination of the trial May 26, 2020. Data were analyzed from December 18, 2020, to May 10, 2022.

Interventions

Patients randomly received pertuzumab (840 mg intravenously [IV], then 420 mg IV every 3 weeks) plus trastuzumab (8 mg/kg IV, then 6 mg/kg IV every 3 weeks) without chemotherapy (group A) or pertuzumab plus trastuzumab (same doses) with either paclitaxel (90 mg/m2 for days 1, 8, and 15, then every 4 weeks for ≥4 months) or vinorelbine tartrate (25 mg/m2 for first administration followed by 30 mg/m2 on days 1 and 8 and every 3 weeks for ≥4 months) followed by pertuzumab plus trastuzumab maintenance after chemotherapy discontinuation (group B).

Main Outcomes and Measures

Overall survival at 24 months by treatment group, PFS for first-line treatment, PFS for second-line treatment, and patient-reported quality of life (QOL).

Results

A total of 210 patients were included in the analysis, with a median age of 58 (range, 26-85) years. For group A, 24-month OS was 79.0% (90% CI, 71.4%-85.4%); for group B, 78.1% (90% CI, 70.4%-84.5%). Median PFS with first-line treatment was 8.4 (95% CI, 7.9-12.0) months in group A and 23.3 (95% CI, 18.9-33.1) months in group B. Unlike expectations, OS and PFS did not markedly differ between populations with ERBB2-enriched and ERBB2-nonenriched cancer. Adverse events were less common without chemotherapy, with small QOL improvements from baseline in group A and stable QOL in group B.

Conclusions and Relevance

The findings of this secondary analysis of a randomized clinical trial suggest that the chemotherapy-free anti-ERBB2 strategy is feasible without being detrimental in terms of OS. The 50-gene prediction analysis of microarray signature could not help to identify the most appropriate patient population for this approach.

Trial Registration

ClinicalTrials.gov Identifier: NCT01835236.

Early Results of the French Multicenter, Randomized SHARE Trial Comparing Whole Breast Irradiation vs. Accelerated Partial Breast Irradiation in Postmenopausal Women with Early-Stage Breast Cancer

PURPOSE/OBJECTIVE(S)

The aim is to report toxicity and cosmetic outcomes at 3 and up to 9 years of follow-up of post-menopausal patients randomized to receive either standard whole breast irradiation (WBI), including hypofractionated options, versus accelerated partial breast irradiation (APBI).

MATERIALS/METHODS

From December 2010 to July 2015, 1006 patients were enrolled in 34 French centers. Among the whole population, 28 patients who did not meet the final selection criteria or withdrew consent were excluded leading to a modified intention to treat analysis dataset of 978 patients (WBI: n = 488; APBI: n = 490). Median age (65y) and tumor stage pT1 (99%) rates were similar in both arms. Patients had conservative surgery with clip placement in the tumor bed. Clear margins (> 2mm) were observed in 99% of the patients. In both arms, 96-97% of the patients had negative sentinel lymph node biopsy. The median time interval between surgery and radiotherapy was 57d in WBI vs 62d in APBI. WBI schedules consisted of 50 Gy in 25 fr+16 Gy (n = 212) or 40 Gy in 15 fr (n = 156) or 42.5 Gy in 16 fr (n = 120). APBI arm consisted of 38.5 Gy or 40 Gy in 10 fr, 2 fr/day. Overall, 94 patients from the APBI arm finally received standard WBI. For statistical considerations, SHARE trial, sponsored by UNICANCER (NCT01247233) is a non-inferiority randomized controlled trial comparing APBI versus WBI in terms of local control as primary objective. Secondary endpoints were severe toxicity (NCI-CTCAE v4 grade ≥ 2), and cosmetic results. For both outcomes, we estimated the cumulative incidences (CI) using Kalbfleish and Prentice method, considering disease relapse, secondary cancer or death as competing events. Treatment effect (APBI vs WBI) was estimated by cause-specific Hazard Ratios (cs-HR) from Cox models.

RESULTS

Median follow-up was 5.8y (range, 0.13-9.5). The number of deaths was 27, and the number of local relapses was 8. Among the 978 patients, 582 and 396 had finally WBI and APBI, respectively. The rates of post-operative hematoma, edema and infection were low: 8-9%, 2%, 3-2%, respectively. When considering any type of severe toxicity, we observed a significant reduction rate in APBI compared to WBI: cs-HR = 0.73 (95% confidence interval: 0.61-0.88); p = 0.001, and 3-year CI of severe toxicity at 45% in WBI vs 36% in APBI arm. The difference was also in favor of APBI when considering breast skin toxicity alone: cs-HR = 0.55 (0.44-0.70), p<0.001 and 3-year CI at 36% in WBI vs 21% in APBI arm. Conversely, for breast other toxicities, WBI was found less toxic than APBI with a 3-year CI of 8% vs 15%, respectively. When considering cosmetic results, we observed no significant difference between the two arms in both evaluations by physicians and patients.

CONCLUSION

Historically SHARE is the first APBI trial that included hypofractionated schedules in the standard arm. We report increased risk of severe toxicity and skin breast toxicity in standard arm as compared with APBI arm without any difference in terms of cosmetic results. Longer follow-up is needed.

Abstract PD3-05: Early results of the French multicenter, randomized SHARE trial comparing whole breast irradiation versus accelerated partial breast irradiation in postmenopausal women with early-stage breast cancer

Purpose: The aim of current analyses is to report toxicity and cosmetic outcomes at 3 and up to 9 years of follow-up of post-menopausal patients randomized to receive either standard external beam whole breast radiotherapy (WBI), including hypofractionated options, versus accelerated partial breast irradiation (APBI). Methods and materials: From December 2010 to July 2015, 1006 patients were enrolled in 34 French centers (503 in each arm). Among the whole population, 28 patients who did not meet the final selection criteria or withdrew consent were excluded leading to a modified intention to treat analysis dataset of 978 patients (WBI: n=488; APBI: n=490). Median age (65y) and tumor stage pT1 (99%) rates were similar in both arms. Patients had conservative surgery with clip placement in the tumor bed. Clear margins (&gt; 2mm) were observed in 99% of the patients. In both arms, 96-97% of the patients had negative sentinel lymph node biopsy (SLNB; median number: 4 in WBI arm and 5 in APBI), luminal BC. Ductal histology was observed 82%. Only 2% and 1% of patients had grade III and pN(i+) disease. The median time interval between surgery and radiotherapy was 57d in WBI vs 62d in APBI. WBI schedules consisted of: 50Gy in 25fr + 16Gy boost (n=212) or 40Gy in 15fr (n=156) or 42.5Gy in 16fr (n=120), while APBI arm consisted of 38.5Gy or 40Gy in 10fr. Overall, 94 patients from the APBI arm finally received standard WBI. For statistical considerations, SHARE trial, sponsored by UNICANCER (NCT01247233) is a non-inferiority randomized controlled trial comparing APBI versus WBI in terms of local control as primary objective. Secondary endpoints were severe toxicity (NCI-CTCAE v4 grade ≥ 2), and cosmetic results, evaluated by doctors and by patients, over the entire follow-up. For both outcomes, we estimated the cumulative incidences (CI) using Kalbfleish and Prentice method, considering disease relapse, secondary cancer or death as competing events. Treatment effect (APBI vs WBI) was estimated by cause-specific Hazard Ratios (cs-HR) from Cox models adjusted on stratification factors. Results: Median follow-up was 5.8y (range, 0.13-9.5). The number of deaths was 27, and the number of local relapses was 8. Among the 978 patients, 582 and 396 had finally WBI and APBI, respectively. The rates of post-operative hematoma, edema and infection were low: 8-9%, 2%, 3-2%, respectively. When considering any type of severe toxicity, we observed a significant reduction rate in APBI compared to WBI: cs-HR=0.73 (95% confidence interval: 0.61-0.88); p=0.001, and 3-year cumulative incidence (CI) of severe toxicity at 45% (41-49) in WBI vs 36% (32-40) in APBI arm. The difference was also in favor of APBI when considering breast skin toxicity alone: cs-HR=0.55 (0.44-0.70), p&lt; 0.001 and 3-year CI at 36% (32-40) in WBI vs 21% (18-25) in APBI arm. Conversely, for breast other toxicities, WBI was found less toxic than APBI: cs-HR= 2.10 (1.51-2.91), p&lt; 0.001, and 3-year CI at 8% (5-10) vs 15% (12-19), respectively. When considering cosmetic results according to the investigator, we observed no significant difference between the two arms: cs-HR=1.04 (0.81-1.33), p=0.26 and 3-year probability of remaining with good to excellent cosmetic results at 77% (73-81) in WBI arm and 78% (74-81) in APBI arm. Findings were similar when considering results according to the patient: cs-HR=1.07 (0.85-1.37), p=0.23, and 3-year probability at 74% (70-78) and 75% (70-79), respectively. Conclusions Historically SHARE is the first APBI trial that included hypofractionated schedules in the standard arm. We reported increased risk of severe toxicity and skin breast toxicity in standard arm as compared with APBI arm without any difference in terms of cosmetic results. Longer follow-up is needed.

Citation Format: Yazid Belkacemi, Isabelle Gabelle-Flandin, Marie-Cécile Le Deley, Adeline Petit, Philippe Guilbert, Julien Geffrelot, Christian Carrie, Eleonor Rivin Del Campo, Chantal Hanzen, Claire Charra-Brunaud, Isabelle Lecouillard, Nicolas Magne, Agnès Tallet, Nicolas Leduc, Blaha Belgadi, Philippe Fourneret, Alexandre Coutte, Esther Capelo, Franck Darloy, Muriel Garcia Ramirez, Philippe Dudouet, Pierre Clavere, Jean-Philippe Suchaud, Guillaume Auzac, Thomas Lacornerie, Jérôme Lemonnier, Céline Bourgier, Eric Lartigau. Early results of the French multicenter, randomized SHARE trial comparing whole breast irradiation versus accelerated partial breast irradiation in postmenopausal women with early-stage 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 PD3-05.

Abstract OT1-10-01: Treatment with Tucatinib in addition to Pertuzumab and Trastuzumab in patients with HER2-positive metastatic breast cancer (HER2+ MBC) after local therapy of isolated brain progression: InTTercePT, a UCBG/GINECO study

Treatment with Tucatinib in addition to Pertuzumab and Trastuzumab in patients with HER2-positive metastatic breast cancer (HER2+ MBC) after local therapy of isolated brain progression: InTTercePT, a UCBG/GINECO study. Background HER2+ MBC patient on first line treatment with pertuzumab and trastuzumab have a 13% risk of developing brain metastasis (BM) as the first site of progression. For such patient with isolated brain progression, guidelines recommend to use central nervous system (CNS) directed therapy whenever possible (stereotactic radiosurgery or surgery or both). These patients will have a higher risk of subsequent brain and systemic progression after local treatment. Therefore, whether systemic treatment should be continued or changed remains an open question. The tyrosine kinase inhibitor tucatinib is an orally bioavailable HER2 inhibitor with validated antineoplastic activity and the ability to cross the blood brain barrier. The randomized HER2CLIMB study, demonstrated that adding tucatinib to trastuzumab/capecitabine improved both progression-free survival (PFS) and overall survival (OS) among HER2+ MBC patients previously treated with trastuzumab, pertuzumab and T-DM1. Particularly, this regimen demonstrated improved antitumor activity in patients with BM, in terms of CNS-PFS and OS. Exploratory analysis of HER2CLIMB and in a phase 1b study, showed patients who continued systemic treatment with tucatinib (in combination either with trastuzumab/capecitabine or TDM-1) after CNS-directed treatment had a better outcome compared with those that discontinued systemic tucatinib-based treatment. These results suggest that for patient in the first line metastatic setting who experience isolated brain progression, adding tucatinib to the trastuzumab/pertuzumab regimen could help control BM, improve PFS, OS and patients’ quality of life. Trial design InTTercePT is an open-label, single-arm, national, multicentric, phase II trial assessing the combination of tucatinib, pertuzumab and trastuzumab. Tucatinib will be administered orally twice daily at 300 mg. Pertuzumab and trastuzumab will be administered at the initial dose of 840 mg and 8 mg/kg respectively following by a maintenance dose of 420 mg and 6mg/kg respectively, 3-weekly. If indicated, hormone therapy is allowed in combination with HER2-directed therapy. Eligibility criteria include HER2+ MBC with isolated brain progression (new or progressive BM with stable or responding systemic disease) under pertuzumab/trastuzumab treatment (± taxane) after complete local treatment (surgery and/or radiation therapy). There is no limit to the number and size of BM. Specific aims To evaluate the efficacy, in terms of PFS rate (RECIST v1.1) of tucatinib in combination with pertuzumab/trastuzumab. Secondary endpoints include OS, brain PFS (RECIST v1.1) and BM response in patient not in complete remission at the brain level after local treatment and safety (NCI-CTCAE v5.0). Statistical methods Given the lack of safety data from this association, two interim safety analysis are planned: after 10 and 20 patients having received at least one dose of the treatments combination during at least one cycle. The number of patients to be included was calculated using Fleming’s single-stage procedure for phase II trials. The sample size calculation was based on a minimum success (non-progression rate at 6 months) considered of interest of p1 = 75% and an uninteresting rate of p0 = 60%. Assuming a unilateral type I error alpha of 10% and a power of 85%, 52 patients are needed. Considering 5% of the patients may be non-evaluable, 55 patients will be included. At the time of analysis, if at least 37 successes are observed, the treatment will be considered as interesting for further investigation. The study is recruiting. By July 1, 2022, 10 patients have been screened and 8 treated (NCT05041842). Funding SeaGen Contact information thomas.bachelot@lyon.unicancer.fr

Citation Format: Thomas Bachelot, Christelle Jouannaud, Benjamin Verret, Sylvie Chabaud, Camille Petrau, Laetitia Stefani, Mony Ung, Isabelle Desmoulins, William Jacot, Caroline Bailleux, Sandrine Marques, Jérôme Lemonnier, Anne-Claire Hardy-Bessard. Treatment with Tucatinib in addition to Pertuzumab and Trastuzumab in patients with HER2-positive metastatic breast cancer (HER2+ MBC) after local therapy of isolated brain progression: InTTercePT, a UCBG/GINECO 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 OT1-10-01.

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 OT1-01-01: A randomised phase II trial of palbociclib and fulvestrant vs standard endocrine therapy in patients with ER positive HER2 negative breast cancer and ctDNA detected molecular relapse during adjuvant endocrine therapy (TRAK-ER)

Background: Most patients with early stage oestrogen receptor positive (ER+) and HER2 negative breast cancer will be cured of their cancer. However, up to 20% of patients may experience disease recurrence in the first 10 years. Molecular relapse of ER+ breast cancer can be detected with circulating tumour DNA (ctDNA) before clinical relapse occurs. Palbociclib, a CDK4/6 inhibitor, plus fulvestrant, a selective oestrogen receptor degrader, is a standard first line therapy for patients with ER+ breast cancer who have relapsed on standard endocrine therapy. We designed TRAK-ER to establish a surveillance system for ctDNA detection and then to assess whether treating patients, who have ctDNA detected molecular relapse, with palbociclib and fulvestrant may defer or prevent relapse. Design: TRAK-ER is a phase 2 multi-centre, randomised, open-label parallel superiority trial in patients with ER+ early breast cancer, recruiting at centres in the UK and France. In the surveillance phase patients will be monitored for molecular recurrence with ctDNA testing. To be eligible for the surveillance phase patients must be aged 18 or over, have ER+ (≥10% or Allred score 6/8 or greater) and HER2 negative breast cancer and have completed their primary surgery, chemotherapy and radiotherapy. Standard endocrine therapy (GnRH analogues, aromatase inhibitors and tamoxifen) must have been received for a minimum of 6 months and a maximum of 7 years and be planned to continue for at least another 3 years. Inclusion criteria in patients who did not receive neoadjuvant chemotherapy are at least one of: (a) four or more involved axillary or positive supraclavicular lymph node; (b) tumour size &gt;5cm; (c) one to three involved axillary lymph nodes together with at least one of: tumour size &gt;3cm, grade 3 or a high genomic risk score. Patients who received neoadjuvant chemotherapy require at least one lymph node positive or a tumour size &gt;3cm after chemotherapy. Invitae Personalized Cancer Monitoring (PCM TM) will be used for ctDNA analysis, a pan-cancer, tumour-informed liquid biopsy test that uses next-generation sequencing to detect minimal or molecular residual disease (MRD) in solid tumours. ctDNA analysis will be every 3 months for up to 3 years. Detection of ctDNA will trigger staging imaging. If no overt metastatic disease is identified, patients will be able to enter the treatment phase of the study, and be 1:1 randomised using minimisation to either remain on standard endocrine therapy or switch to palbociclib plus fulvestrant. Those who are allocated to remain on endocrine therapy are allowed to continue on the same therapy or change standard endocrine therapy. Duration of palbociclib and fulvestrant will be 2 years, or until relapse. Up to 1300 patients will enrol for tissue screening to allow 1100 patients to enter into ctDNA surveillance. 132 patients will enter the treatment part of the study. The primary endpoint of the surveillance phase is ctDNA detection rate. The primary endpoint of the treatment phase is relapse free survival (RFS). RFS will be calculated in the intention to treat population using Kaplan Meier methods from the date of randomisation to the date of recurrence or death from any cause. Secondary endpoints include relapse free interval, invasive disease free survival, distant recurrence free survival, overall survival and ctDNA clearance. (NCT04985266)

Citation Format: Nicholas Turner, Edward R. Phillips, Catey Bunce, Marie Robert, Caroline Bailleux, Isaac Garcia-Murillas, Komel Khabra, Iain Macpherson, Ciara S. O’Brien, Alicia F. Okines, Carlo Palmieri, Peter Schmid, Claire Swift, Sabrina Yara, Simon Connolly, Jérôme Lemonnier, Dymphna Lee, Fabrice Andre. A randomised phase II trial of palbociclib and fulvestrant vs standard endocrine therapy in patients with ER positive HER2 negative breast cancer and ctDNA detected molecular relapse during adjuvant endocrine therapy (TRAK-ER) [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 OT1-01-01.

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 P1-10-13: Economic comparison of standard external beam whole breast (WBI) versus accelerated partial breast irradiation (ABPI) in postmenopausal women with early-stage breast cancer. Results from the French SHARE randomized trial

Purpose: The economic evaluation reports the incremental cost utility ratio and budget impact of APBI vs standard external beam WBI for the treatment of post-menopausal women with early stage breast cancer.

Methods and materials: We compared 488 women in the standard arm (1 fraction per day delivered 5 days per week over 3 or 6/6.5 weeks) to 490 women in the ABPI arm (ten fractions delivered twice per day over one week). We took the perspective of the healthcare system, a 3-year time horizon; the outcomes were quality adjusted life years (QALYs). QALYs were calculated from the EQ5D5L questionnaires at baseline, 3 months, 6 months, 12 months and yearly after irradiation; scores were converted into utilities using the French value set and QALYs computed with the area under the curve approach. Measures of within-trial use of hospital resources were based on routine hospital data via patient-level information. We used the itemized and DRG cost data from each individual patient. Transportation costs were added in a sensitivity analysis. A 2.5% discount rate was applied to costs and QALYs. An incremental analysis with differences in costs and QALYs was performed to calculate the cost utility ratio. Bootstrapping was used to quantify uncertainty on the joint distribution of costs and outcomes, and 1,000 paired estimates of mean differential costs and QALYs were reported on a cost-effectiveness plane. A budget impact analysis based on incidence of breast cancer estimates was added. All analyses followed the intent to treat principle.

Results: Cost and utilities were available for the entire population. Costs and QALY results are presented in table 1. The 2 925 € (95% IC, -3 364 €; - 2 452 €) significant difference in total costs favoring ABPI was driven by the difference in radiotherapy costs and partly by lower transportation costs. No significant difference was found in QALYs. Figure 1 shows the uncertainty of the joint distribution of costs and QALYs. All replication are in the lower half of the plane indicating that ABPI is cost saving with QALYs distributed on each side of the vertical axis indicating equal distribution of QALYs. would be eligible for treatment with ABPI. The uptake of ABPI for 16% of these women would result in a 16 million€ cost saving.

Conclusions: At three years, ABPI for the treatment of postmenopausal women with early-stage breast cancer was found to be cost saving, with no difference in outcome measured by QALYs.

Table 1.

Figure 1.

Citation Format: Alicia Le Bras, Yazid Belkacemi, céline Bourgier, Isabelle Gabelle-Flandin, Adeline Petit, Philippe Guilbert, Julien Geffrelot, Christian Carrie, Eleonor RIVIN DEL CAMPO, Chantal Hanzen, claire charra-brunaud, Guillaume Auzac, Thomas Lacornerie, Jérôme Lemonnier, Eric Lartigau, Isabelle Durand-Zaleski. Economic comparison of standard external beam whole breast (WBI) versus accelerated partial breast irradiation (ABPI) in postmenopausal women with early-stage breast cancer. Results from the French SHARE randomized 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 P1-10-13.

Abstract P2-02-07: Patients’ selection of daily timing of oral intake of adjuvant hormonotherapy (HT) and everolimus (EVE) for high risk early breast cancer in the UCBG-UNIRAD phase III trial

Background: Everolimus (EVE) addition to adjuvant hormonotherapy (HT) for high-risk early breast cancer (BC) did not improve 3-year disease-free survival (DFS) compared with ET alone in the randomized UNIRAD trial (NCT01805271) (1). Most patients (pts) withdrew from EVE for adverse events nearly midway before the expected treatment duration of 2 years. The main EVE target involves m-TOR-induced S6 protein phosphorylation, which is controlled by the molecular circadian clock in mice and cells. Toward the analysis of possible circadian time-dependencies in EVE toxicities and efficacy, we first determine the actual distribution of the daily times chosen by the patients for both oral EVE and HT intakes.

Patients and methods: The registered pts were asked to record the clock hours they chose for both HT and EVE or placebo (PLAC) intakes within four possible daily 6-h slots, i.e. from 06:00 to 11:59 (morning), 12:00 to 17:59 (midtime), 18:00 to 23:59 (evening), or 24:00 to 05:59, (night) in a daily diary throughout their participation in the trial. Modifications in times of drugs intake were reported. Comparisons between groups involved Kruskal-Wallis sum test and Pearson’s Chi-squared and Fisher’s exact tests.

Results: Out of 1,278 randomized patients, 1063 (83,1 %) recorded the times of EVE or PLAC intakes, 852 recorded those for HT intakes. Only 10 pts reported night EVE/PLAC intakes and were not considered here. Of the 1053 evaluated pts; 549 pts took EVE/PLAC in the morning, 82 pts at midtime and 422 in the evening. As compared with evening intakes, morning or midtime intakes of EVE or PLAC were significantly associated with an older age, and post-menopausal status, whilst younger and premenopausal women preferentially chose evening intakes (p&lt; 0.001 for both). Consistently, HT with aromatase inhibitors (AI) were mostly taken in the morning or at midtime, whereas tamoxifene (TAM) was mostly taken the evening (p = 0.001). Tumor size, lymph nodes involvement, histological grade, hormonal receptors status, and EVE initial dose were similarly distributed among the three time slots (Table 1). A similar distribution of oral intake times as in the whole timing study population was found according to age, menopausal status and HT type in the EVE arm (N=508 pts), and in the HT population (+/- EVE or PLAC) (N=852 pts). Initial oral timing intake was modified for EVE by 50 of 508 pts (10%) and for HT by 10 of 852 pts (1%).

Conclusion: To the best of our knowledge, it is the first time that the patients’ spontaneous selection of daily times for oral intakes of a targeted agent (EVE) and HT is reported in a large series of early breast cancer pts. Age and menopausal status were important determinants of patient-selected daily timing intakes of both EVE and HT, as well as HT types. These findings will be carefully considered in the analyses of possible EVE and HT timing effects on adverse events and efficacy of the current adjuvant regimens.

1) Bachelot T et al, J Clin Oncol. 2022 May 23

Abstract PD17-02: ctDNA Molecular Response based on breast cancer driver mutations predicts progression in aromatase inhibitor-sensitive first line treatment of oestrogen receptor-positive (ER+) HER2-negative (HER2-) advanced breast cancer

Background: The combination of a CDK4/6 inhibitor and an aromatase inhibitor (AI) is the gold standard for AI-sensitive first line treatment of ER+ HER2- advanced breast cancer. Nevertheless, some patients progress rapidly and may benefit from alternative strategies. Early ctDNA dynamics have been shown to predict disease course in several clinical situations. Here, we use samples from the PADA-1 trial to assess this strategy for patients receiving AI and palbociclib as first line treatment. PADA-1 was designed to assess the clinical utility of sequential analysis of ctDNA for emerging ESR1 mutations to trigger an early switch from AI plus palbociclib to fulvestrant plus palbociclib treatment. The study included 1,017 patients and was positive on its primary end-point. The objective of this translational study was to analyze the predictive value of 4-week molecular response (MR) for patient progression. Material & Method: First, a CLIA-validated targeted next-generation sequencing-based test (Guardant360 Response) was used to characterize changes in ctDNA level via detection of somatic single-nucleotide variants (SNVs), insertion/deletion mutations (indels), and gene fusions in 74 genes frequently mutated in cancer. A second analysis was restricted to cancer-associated mutations in 11 genes commonly mutated in breast cancer (PIK3CA, GATA3, TP53, AKT1, ERBB2, BRCA1, BRCA2, ATM, ESR1, PALB2 and RB1). The threshold for molecular response was defined as ≥ 50% decrease in ctDNA (MR score &lt; 0.5). Subjects with ctDNA levels below the test’s limit of quantitation (ctDNA-low) were considered molecular responders. Results: 372 subjects with matched baseline and 4-weeks samples were available for analysis. Of these, 134 subjects (36%) were ctDNA-low, and 238 subjects (64%) quantifiable. Among the quantifiable subjects, 183 (77%) were molecular responders (MR+, MR &lt; 0.5), and 55 (23%) were not (MR–, MR ≥ 0.5). PFS was moderately improved for both MR+ and ctDNA-low relative to MR– (HR=0.61 (95%CI 0.44-0.85), p&lt; 0.01) over the full 29 months of follow up. Differential PFS event rate was observed only in the first 8 months following ctDNA assessment; during this time MR+ and ctDNA-low were associated with more significantly decreased risk of progression (HR 0.24, 95% CI 0.13 – 0.43, p=0.0001). Limiting ctDNA assessment to genes commonly mutated in breast cancer enhanced the predictive power of MR (HR=0.08, 95% CI 0.04 0.17, p&lt; 0.001, for MR+ and ctDNA-low vs. MR– across 8 months post-assessment); however, fewer samples were quantifiable by this method (169 [45%] quantifiable; 203 [55%] ctDNA-low). Combining MR status with additional molecular features (e.g.tumor mutational burden and maximum mutation allele fraction) did not improve prediction of non-response. Conclusion: Changes in ctDNA fraction during the first weeks of treatment are predictive of long term clinical benefit on an individual patient basis, particularly during the first year of therapy. Adjusting the MR threshold and/or limiting to genes known to be relevant in the specific tumor can tailor the assessment of ctDNA change to specific clinical scenarios where greater sensitivity or specificity may be required. The identification of patients at high risk for early clinical failure at the onset of treatment may allow for therapy escalation and/or change to improve outcome in this population. Funding: Pfizer and Guardant Health

Citation Format: Caroline Bailleux, Thomas Bachelot, Francois-Clement Bidard, Anne-Claire Hardy-Bessard, Ivan Bièche, Anne Pradines, Florian Clatot, thibault DE LA MOTTE ROUGE, Jean-Luc Canon, Barbara Pistilli, Kyle Chang, Katie J. Quinn, Heather L. Gustafson, Florence Dalenc, Cyril Foa, Hanifa Ammarguellat, Chantal Bernard-Marty, Brigitte Lucas, Sophie Barthier, Fabrice Lorchel, Olivier Gisserot, Laurent Arnould, Marjorie Mauduit, Jérôme Lemonnier, Frédérique Berger, Suzette Delaloge, Fabrice Andre. ctDNA Molecular Response based on breast cancer driver mutations predicts progression in aromatase inhibitor-sensitive first line treatment of oestrogen receptor-positive (ER+) HER2-negative (HER2-) advanced 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 PD17-02.

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.

Final results from a phase III randomized clinical trial of adjuvant endocrine therapy ± chemotherapy in women ≥ 70 years old with ER+ HER2- breast cancer and a high genomic grade index: The Unicancer ASTER 70s trial

500

Background: Benefit of adjuvant chemotherapy (CT) in addition to endocrine therapy (ET) remains controversial for patients (pts) aged ≥ 70 years with oestrogen receptors-positive (ER+) HER2-negative (HER2-) breast cancer (BC). In a large prospective trial, we first assessed the tumour genomic grade index (GGI) in all pts, and second, randomized pts with a high GGI between CT + ET vs. ET alone. Methods: Eligible pts were women ≥ 70 years with ER+ HER2- primary BC or isolated local relapse, irrespective of other characteristics, for whom adjuvant systemic treatment was considered. G8 score, Charlson comorbidity index (CCI) and 4-year mortality Lee score were collected at baseline. GGI was centrally performed by RT-PCR on FFPE samples. Pts with low GGI were not recommended to receive CT and were followed in an observational cohort. Pts with high (+ equivocal) GGI were randomized 1:1 to CT + ET vs. ET alone, using G8, pN and centre for stratification. Investigators chose between 3 CT regimens: 4 cycles of doxorubicin/cyclophosphamide, non-pegylated liposomal doxorubicin/cyclophosphamide or docetaxel/cyclophosphamide, given q3w with G-CSF. Standard ET consisted of 5 years of aromatase inhibitor, tamoxifen or a sequence based on tolerance. Based on CALGB 49907 results, the primary objective was to demonstrate an overall survival (OS) benefit for CT (4-year assumptions 87.5 vs 80%, HR=0.60) in the intent to treat (ITT) population. With 171 events, the trial had 90% power to demonstrate a difference with a bilateral test α=0.05. Secondary objectives included BC specific survival (BCSS), invasive disease-free survival (iDFS), event-free survival (EFS), competing events, cost-effectiveness and Q-TWiST analysis, geriatric dimensions, willingness and quality of life. Results: Between 04/2012 and 05/2016, 1,969 pts from 61 French and 12 Belgian centres were enrolled. Of them, 1,089 (55%) were randomized between CT + ET and ET alone. Median follow-up was 5.8 years at the data cut-off (17/12/2021) with 180 OS events observed. Median age was 75 (70-92), G8 score, CCI and Lee score being >14, ≤ 2, and ≤ 8 in 60%, 62% and 84% of pts, respectively. Tumours were ≥ pT2, pN+, isolated local relapses, with histological grade III, in 56%, 46%, 11% and 39% of cases, respectively. No significant OS difference was observed between arms (HR 0.85 [0.64-1.13], p=0.2538); 4-year OS was 90.5% in the CT + ET arm and 89.7% in the ET alone arm. The forest plot could not identify any subgroup deriving significant benefit from CT. ITT and per protocol analysis of secondary objectives (BCSS, iDFS, EFS) showed similar results. Conclusions: In this large phase III trial, we did not find a statistically significant OS benefit with the addition of CT to ET after surgery for ER+ HER2- BC with a high GGI. Analysis of the other outcome measures will be presented. Clinical trial information: NCT0156405.

Survival outcomes after neoadjuvant letrozole and palbociclib versus third generation chemotherapy for patients with high-risk oestrogen receptor-positive HER2-negative breast cancer

BACKGROUND

Besides their development as additional adjuvant treatments, CDK4/6 inhibitors combined with endocrine therapy could represent less toxic alternatives to chemotherapy in postmenopausal women with high-risk oestrogen receptor-positive, HER2-negative breast cancer currently a candidate for chemotherapy. The multicentre, international, randomised phase 2 NEOPAL trial showed that the letrozole-palbociclib combination led to clinical and pathological responses equivalent to sequential anthracycline-taxanes chemotherapy. Secondary objectives included survival outcomes.

METHODS

Secondary end-points of NEOPAL included progression-free survival (PFS) and invasive-disease free survival (iDFS) in the intent-to-treat population. Exploratory end-points were overall survival (OS) and breast cancer specific survival (BCSS) in the intent-to-treat population, as well as iDFS, OS and BCSS according to the administration of chemotherapy.

RESULTS

Hundred and six patients were randomised. Pathological complete response rates were 3.8% and 5.9%. Twenty-three of the 53 patients in the letrozole-palbociclib arm received postoperative adjuvant chemotherapy. At a median follow-up of 40.4 months [0-56.6], 11 progressions have been observed, of which three were in the letrozole-palbociclib and 8 in the control arm. PFS (HR = 1.01; [95%CI 0.36-2.90], p = 0.98) and iDFS (HR = 0.83; [95%CI 0.31-2.23], p = 0.71) did not differ between both arms. The 40 months PFS rate was 86.7% [95%CI 78.0-96.4] and 89.9% [95%CI 81.8-98.7] in letrozole-palbociclib and control arms, respectively. Outcomes of patients who did not receive chemotherapy were not statistically different from those who received it.

CONCLUSIONS

NEOPAL suggests that a neoadjuvant letrozole-palbociclib strategy may allow sparing chemotherapy in some patients with luminal breast cancer while allowing good long-term outcomes. Larger confirmatory studies are needed.

Randomised, open-label, multicentric phase III trial to evaluate the safety and efficacy of palbociclib in combination with endocrine therapy, guided by ESR1 mutation monitoring in oestrogen receptor-positive, HER2-negative metastatic breast cancer patients: study design of PADA-1

INTRODUCTION

The combination of a CDK4/6 inhibitor with an aromatase inhibitor (AI) has recently become the gold standard for AI-sensitive first line treatment of oestrogen receptor-positive (ER+) HER2-negative (HER2-) advanced breast cancer. However, most patients receiving this combination will ultimately progress and require further therapies.Several studies have demonstrated that the onset of a ESR1 gene mutation lead to AIs resistance in the advanced setting. ESR1 mutations can be detected in circulating tumour DNA (ctDNA) using a digital PCR assay. Our study aims to prove the clinical efficacy of periodic monitoring for emerging or rise of ESR1 mutations in ctDNA to trigger an early change from AI plus palbociclib to fulvestrant plus palbociclib treatment while assessing global safety.

METHODS

PADA-1 is a randomised, open-label, multicentric, phase III trial conducted in patients receiving AI and palbociclib as first line therapy for metastatic ER +HER2- breast cancer. 1000 patients will be included and treated with palbociclib in combination with an AI. Patients will be screened for circulating blood ESR1 mutation detection at regular intervals. Patients for whom a rising circulating ESR1 mutation is detected without tumour progression (up to N=200) will be randomised (1:1) between (1) Arm A: no modification of therapy; and (2) Arm B: palbociclib in combination with fulvestrant, a selective ER down-regulator. At tumour progression, an optional crossover will be offered to patients randomised in arm A. The coprimary endpoints are (1) Grade ≥3 haematological toxicities and their associations with baseline characteristics and (2) progression-free survival in randomised patients.

ETHICS AND DISSEMINATION

The study has been approved by the French medicines agency (ANSM) and by an ethics committee (ref 01/17_1 CPP Ouest-IV Nantes) in January 2017. The trial results will be published in academic conference presentations and international peer-reviewed journals.

TRIAL REGISTRATION NUMBERS

EudraCT: 2016-004360-18; NCT03079011.

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.

Abstract CT189: Characterization of ESR1 mutations at metastatic relapse and outcome under first line aromatase inhibitor and palbociclib in the PADA-1 trial

Background: Palbociclib (Pal) combined with an aromatase inhibitor (AI) is a standard of care as first line therapy in ER+ HER2- metastatic breast cancer (MBC). Cell-free DNA (cfDNA) ESR1 mutation (ESR1mut) status prior to treatment initiation may be associated with shorter progression-free survival (PFS) under first line Pal+AI; however, the impact of the exact type of ESR1mut, of their quantitative levels and clonality are unknown. In a subsidiary analysis of the first line PADA-1 phase 3 trial, cfDNA samples previously detected as positive by ddPCR were submitted to NGS; mutations types, level and clonality were correlated with patient outcomes under first line Pal+AI. Methods: PADA-1 (NCT03079011) is a phase III trial testing the clinical utility of real time ESR1mut detection in the blood of patients treated with AI-Pal. Main inclusion criteria are patients with ER+ HER2- MBC, who never received adjuvant AI or completed adjuvant AI for &gt;12 months, with neither prior therapy for MBC nor visceral crisis. ESR1mut are tracked in cfDNA from up to 4ml of plasma by a single ddPCR assay targeting E380, L536, Y537 and D538 hotspots (i.e. &gt;90% of known ESR1 activating mutations) with 0.1% sensitivity (Jeannot et al, Oncogene 2020). We sequenced the ddPCR positive cfDNA samples using a short amplicon-based NGS panel spanning 30 genes, including the full sequence of ESR1. We assessed for the correlation between PFS and ESR1mut type (NGS), absolute level (copy/ml, ddPCR) or variant allelic frequency (VAF, NGS & ddPCR), and clonality (NGS, pending the detection of other driver mutations). Results: Among the 1,017 included patients, N=33 (3.2%) had an ESR1mut detected by ddPCR at inclusion (median VAF= 2.5%, range (0.09-46.6%). 26/33 left-over cfDNA samples were available for NGS. ESR1mut VAFs retrieved by NGS and ddPCR showed an excellent intraclass correlation coefficient (ICC= 0.98; 95% CI [0.89;0.99]). In N=3 samples with low VAF by ddPCR (&lt;1%), NGS was not able to detect ESR1mut. ESR1 codons 380, 536, 537 and 538 were mutated in N=5, 6, 10 and 7 patients, respectively (5 patients (19.2%) having polyclonal mutations). Among evaluable patients, ESR1mut were found clonal and subclonal in 11 (47.8%) and 12 (52.2%) patients, respectively. After a median follow-up of 24.8 months (range 0-41.9 months) (485 PFS events among the 1,017 included patients), ESR1mut detection at inclusion was found to be a prognostic factor for PFS (median PFS = 11.6 months 95% CI [8.3; NR] vs 28.5 months 95% CI [23.3;30.2]; HR= 2.2 95% CI = [1.4;3.4]). ESR1mut type, clonality and baseline levels had no significant additional impact on PFS. Conclusion: Presence of ESR1mut detected in cfDNA at metastatic relapse are associated with a shorter PFS under first line AI and palbociclib. ddPCR and NGS yielded similar quantitative results, while supplementary information obtained by NGS (mutation type and clonality) did not add further prognostic information. Funding: Pfizer, French National Cancer Institute (Grant PRT-K 2020-041)

Citation Format: Anne Pradines, Céline Callens, Aurélia Doussine, Ivan Bièche, Jérôme Lemonnier, Marjorie Mauduit, Thomas Bachelot, Florence Dalenc, Alain Lortholary, Barbara Pistilli, Thibault De La Motte Rouge, Renaud Sabatier, Jean-Marc Ferrero, Sylvain Ladoire, Frédérique Berger, François-Clément Bidard. Characterization of ESR1 mutations at metastatic relapse and outcome under first line aromatase inhibitor and palbociclib in the PADA-1 trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT189.

Efficacy of AI and palbociclib in ER+ HER2- advanced breast cancer patients relapsing during adjuvant tamoxifen: An exploratory analysis of the PADA-1 trial

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Background: In PADA-1 (NCT03079011), a phase III trial testing the clinical utility of ESR1mut detection, ER+ HER2- advanced breast patients (ABC pts) received Aromatase Inhibitor (AI) and Palbociclib (Pal) +/- LHRH agonist as first line therapy. PADA-1 was open to “AI-sensitive” pts, including those with de novo stage IV disease or metastatic relapse after adjuvant endocrine therapy but also pts with metastatic relapses during adjuvant tamoxifen (TAM). In this subsidiary analysis, we report the efficacy of AI+PAL as first line therapy in patients relapsing on adjuvant TAM. Methods: Main inclusion criteria in PADA-1 are: pre- or post-menopausal pts with ER+ HER2- ABC, who did not receive any prior therapy for ABC and who had no adjuvant AI or completed adjuvant AI for > 12 months or who had disease recurrence while on adjuvant TAM. Results: From 04/2017 to 01/2019, 1017 ABC pts have been included in PADA-1, of which 115 (11.3%) had a metastatic relapse while on adjuvant TAM (TAM only (N = 112) or TAM+GnRH agonist (N = 3)). Median age at inclusion was 46 years (range 25-81), and 58 (50.4%) patients had visceral disease. The median PFS under AI+PAL was 20.4 months (95%CI16.1;27.8) in patients relapsing during adjuvant TAM. In contrast, median PFS in patients with de novo metastatic disease and metastatic relapses after the completion of adjuvant endocrine therapy were 30.6 months (95%CI26.7;Not reached) and 27.8 months (95%CI24.1;30.)], respectively. A subgroup analysis among patients relapsing on adjuvant TAM showed that those relapsing during the first two years of adjuvant TAM had a shorter PFS (11.4 months 95%CI[8.7;20.7]) than those relapsing after 2 years of adjuvant TAM (23.8 months 95%CI[20.2;Not reached]). Conclusions: To our knowledge, these are the first data on first line AI+CDK4/6 inhibitor in patients relapsing on adjuvant TAM. While PFS on AI + PAL appears primarily driven by endocrine resistance status, our data show that AI+PAL is a valuable option also in patients relapsing during adjuvant TAM. Clinical trial information: NCT03079011 .

VEGF-Related Germinal Polymorphisms May Identify a Subgroup of Breast Cancer Patients with Favorable Outcome under Bevacizumab-Based Therapy-A Message from COMET, a French Unicancer Multicentric Study

The prospective multicenter COMET trial followed a cohort of 306 consecutive metastatic breast cancer patients receiving bevacizumab and paclitaxel as first-line chemotherapy. This study was intended to identify and validate reliable biomarkers to better predict bevacizumab treatment outcomes and allow for a more personalized use of this antiangiogenic agent. To that end, we aimed to establish risk scores for survival prognosis dichotomization based on classic clinico-pathological criteria combined or not with single nucleotide polymorphisms (SNPs). The genomic DNA of 306 patients was extracted and a panel of 13 SNPs, covering seven genes previously documented to be potentially involved in drug response, were analyzed by means of high-throughput genotyping. In receiver operating characteristic (ROC) analyses, the hazard model based on a triple-negative cancer phenotype variable, combined with specific SNPs in VEGFA (rs833061), VEGFR1 (rs9582036) and VEGFR2 (rs1870377), had the highest predictive value. The overall survival hazard ratio of patients assigned to the poor prognosis group based on this model was 3.21 (95% CI (2.33-4.42); p < 0.001). We propose that combining this pharmacogenetic approach with classical clinico-pathological characteristics could markedly improve clinical decision-making for breast cancer patients receiving bevacizumab-based therapy.

Abstract P6-08-12: Feasibility of a nation-wide family-based study to assess cancer risks in families with a predicted pathogenic variant identified through hereditary breast and ovary multi-gene panel testing: The TUMOSPEC study

Background. Assessment of the age-dependent cancer risk conferred by germline predicted pathogenic variants (PPV) in cancer susceptibility genes is often hampered by the way the data are collected. Cohort-based data frequently contain an overrepresentation of patients carrying a gene variant of interest and an underrepresentation of cancer-free gene variant carriers. In order to overcome this problem, penetrance estimates can be grounded on family-based study designs, through the evaluation of index patients (IP) and their family relatives. The purpose of the TUMOSPEC study is to estimate the penetrance of PPV in genes whose literature data are currently inaccurate or limited and to determine their associated tumour spectrum. This will lead to an appropriate assessment of the clinical utility of testing these genes. Methods. IP are enrolled consecutively among patients who are being offered a germline genetic test in a hereditary breast and ovary cancer (HBOC) context in a participating cancer genetics clinics. A panel of 24 genes (ATM, BAP1, BARD1, BRIP1, CHEK2, FANCM, FAM175A, MRE11A, NBN, STK11, RINT1, XRCC2, PALB2, MLH1, MSH2, MSH6, PMS2, CDH1, PTEN, RAD50, RAD51B, RAD51C, RAD51D, TP53) is tested in parallel of BRCA1 and BRCA2. If a PPV is identified, the IP is asked to give her/his first- and second-degree relatives and cousins address, regardless of their health status. Each relative is then contacted by the study coordinating centre (CC) to be invited. Each participant completes an epidemiological questionnaire addressing personal medical history and exposure to various risk factors, and provides a saliva sample to determine if he/she carries the familial PPV. The CC collects questionnaires, family history, clinical and genetic data. Results. Enrolment for the feasibility study takes place between Sep. 2017 and Dec. 2019 at each of the 46 participating french clinics. In June 2019, the study included 3,298 IP. So far, the CC received 1,241 TUMOSPEC panel results (37.6%) with a mean delay of 5 months [0.7 -17.5]. Among them, 169 carried a PPV in at least one of the genes (totalizing 183 PPV). Additionally, 44 IP with PPV identified beforehand were enrolled (table 1). Relatives’ invitation of these 213 IP began in June 2018. Among the relatives of the first 29 index cases contacted so far, 4.6 relatives per family consented to participate. Conclusions. The feasibility study showed that inclusion process is well adapted and that the communication between the various partners (clinicians, biologists, investigators and study participants) is quite smooth. Rates of inclusion for invited relatives (50%), for IP questionnaire completion (45%) and relatives biological sample collection (50%) are also very satisfactory and yet underestimated due to the recent start of relatives inclusions. Overall, this study shows that it is feasible to conduct a large-scale study to gather sufficient number of positive families for each gene included in the panel in a reasonable interval of time. This on-going national effort will allow to appropriately assess cancer risks cancer in families with a PPV in a gene often included in HBOC multi-gene panels. This is an essential step to optimize clinical management guidelines specific to each gene, and will represent a valuable resource for future research on the genetics of breast and ovary cancers.

Number of PPV identified in IPGeneATMCHEK2PALB2RAD51CBRIP1RAD51DMSH6RAD50PMS2MRE11ANBNMSH2MLH1CDH1BARD1TP53STK11XRCC2RINT1BAP1RAD51BFAM175AFANCMPTENNumber of PPV512019161111111010999865544322110

Citation Format: Olivier Caron, Séverine Eon-Marchais, Sarah Bonnet-Boissinot, Juana Beauvallet, Marie-Gabrielle Dondon, Chrystelle Colas, Florence Coulet, Capucine Delnatte, Claude Houdayer, Christine Lasset, Jérôme Lemonnier, Michel Longy, Catherine Nogues, Dominique Stoppa-Lyonnet, Dominique Vaur, Fabienne Lesueur, Nadine Andrieu, TUMOSPEC Investigators Group, UNICANCER Groupe Génétique et Cancer. Feasibility of a nation-wide family-based study to assess cancer risks in families with a predicted pathogenic variant identified through hereditary breast and ovary multi-gene panel testing: The TUMOSPEC study [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-08-12.

Abstract P5-11-22: Clinical and biological efficacy of first line AI and palbociclib in ER+ HER2- MBC with detectable circulating ESR1 mutation prior to treatment initiation

Background: In ER+ HER2- metastatic breast cancer (MBC), activating ESR1 mutations (ESR1mut) confer resistance to aromatase inhibitors (AI) when used as single agent. The impact of ESR1mut, when detected at baseline (prior to the initiation of therapy), on the efficacy of first line combined AI- CDK4/6 inhibitor therapy remains however unknown.

Methods: The PADA-1 phase 3 trial (NCT03079011) aims at evaluating the utility of monitoring the onset of ESR1mut in cell-free DNA (cfDNA) from patients (pts) receiving AI-palbociclib, as a biomarker to trigger a switch from AI to fulvestrant. Main inclusion criteria were pts with no prior therapy for MBC and with no overt resistance to AI (i.e. no adjuvant AI or adjuvant AI completed &gt;12 months prior to the metastatic relapse). The present exploratory analysis evaluated the biological and clinical outcome of patients who tested positive for ESR1mut at baseline (before any treatment).

Results: From 04/2017 to 01/2019, N=1017 ER+ HER2- MBC pts were included and had their cfDNA tested for ESR1mut at inclusion and during therapy (at 1 month and then every 2 months). N=33/1017 pts had a detectable circulating ESR1mut at inclusion (3.2%, 95%CI [2.2;4.5]), with a median allelic frequency (AF) of 2.5% (range: 0.1- 46%). First, we evaluated the kinetics of ESR1mut in the 33 ESR1mut-positive pts at inclusion. N=1 pt died after 1 month on treatment. In N=25/32 pts (78%), ESR1mut became undetectable (AF&lt;0.1%) within the first 5 months on treatment, with a median time to ESR1mut ‘clearance’ in cfDNA of 34 days 95%CI[29;91d]. Among these 25 pts, with a median follow-up of 10 months (range 0-25.1m): 14 pts (56%) had ESR1mut detected again in cfDNA during AI-palbociclib therapy; 2 pts (8%) experienced a disease progression with no ESR1mut detected; the remaining 9 patients (36%) are still both ESR1mut -free and disease progression-free at time of analysis. Secondly, we evaluated the prognostic impact of cfDNA ESR1mut status at inclusion on progression-free survival (PFS) under AI palbociclib treatment, with an overall median follow-up time of 12.4 months (range: 0-25.3m). The 33 ESR1mut-positive pts experienced a shorter PFS (median PFS: 17.5mo, 95%CI=[10.5-NR]) than the 984 ESR1mut-negative pts (median PFS not reached), with an estimated HR= 2.8, 95%CI=[1.6;5].

Conclusions: ESR1mut are rarely detected in the cfDNA of ER+ HER2- MBC patients with no overt resistance to AI. The quick ‘clearance’ of ESR1mut observed in most patients following treatment initiation and the observed 17.5 months-long median PFS both suggest that the AI palbociclib combination retain clinical activity in ESR1mut-positive MBC. However, in most patients, these mutations were eventually detected again later during therapy and ESR1mut- positivity was associated with a significantly shorter PFS, suggesting that ESR1mut positivity at baseline could accelerate the onset of resistance to AI-palbociclib.

Funding: Pfizer

Citation Format: François-Clément Bidard, Céline Callens, Florence Dalenc, Barbara Pistilli, Thibault de la Motte Rouge, Florian Clatot, Véronique D'Hondt, Luis Teixeira, Sibille Everhard, Hélène Vegas, Jérôme Lemonnier, Ivan Bieche, Anne Pradines, Jean-François Paitel, Dominique Spaeth, Jean-Luc Canon, Isabelle Moullet, Jean-Yves Pierga, Frédérique Berger, Thomas Bachelot, Suzette Delaloge. Clinical and biological efficacy of first line AI and palbociclib in ER+ HER2- MBC with detectable circulating ESR1 mutation prior to treatment initiation [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-11-22.

Association of body mass index and cardiotoxicity related to anthracyclines and trastuzumab in early breast cancer: French CANTO cohort study

BACKGROUND

In patients treated with cardiotoxic chemotherapies, the presence of cardiovascular risk factors and previous cardiac disease have been strongly correlated to the onset of cardiotoxicity. The influence of overweight and obesity as risk factors in the development of treatment-related cardiotoxicity in breast cancer (BC) was recently suggested. However, due to meta-analysis design, it was not possible to take into account associated cardiac risk factors or other classic risk factors for anthracycline (antineoplastic antibiotic) and trastuzumab (monoclonal antibody) cardiotoxicity.

METHODS AND FINDINGS

Using prospective data collected from 2012-2014 in the French national multicenter prospective CANTO (CANcer TOxicities) study of 26 French cancer centers, we aimed to examine the association of body mass index (BMI) and cardiotoxicity (defined as a reduction in left ventricular ejection fraction [LVEF] > 10 percentage points from baseline to LVEF < 50%). In total, 929 patients with stage I-III BC (mean age 52 ± 11 years, mean BMI 25.6 ± 5.1 kg/m2, 42% with 1 or more cardiovascular risk factors) treated with anthracycline (86% epirubicin, 7% doxorubicin) and/or trastuzumab (36%), with LVEF measurement at baseline and at least 1 assessment post-chemotherapy were eligible in this interim analysis. We analyzed associations between BMI and cardiotoxicity using multivariate logistic regression. At baseline, nearly 50% of the study population was overweight or obese. During a mean follow-up of 22 ± 2 months following treatment completion, cardiotoxicity occurred in 29 patients (3.2%). The obese group was more prone to cardiotoxicity than the normal-weight group (9/171 versus 8/466; p = 0.01). In multivariate analysis, obesity (odds ratio [OR] 3.02; 95% CI 1.10-8.25; p = 0.03) and administration of trastuzumab (OR 12.12; 95% CI 3.6-40.4; p < 0.001) were independently associated with cardiotoxicity. Selection bias and relatively short follow-up are potential limitations of this national multicenter observational cohort.

CONCLUSIONS

In BC patients, obesity appears to be associated with an important increase in risk-related cardiotoxicity (CANTO, ClinicalTrials.gov registry ID: NCT01993498).

TRIAL REGISTRATION

ClinicalTrials.gov NCT01993498.

Letrozole and palbociclib versus chemotherapy as neoadjuvant therapy of high-risk luminal breast cancer

Background

Palbociclib is a CDK4/6 inhibitor with demonstrated efficacy and safety in combination with endocrine therapy in advanced luminal breast cancer (LBC). We evaluated the respective efficacy and safety of chemotherapy and letrozole-palbociclib (LETPAL) combination as neoadjuvant treatment in patients with high-risk LBC.

Patients and methods

NeoPAL (UCBG10/4, NCT02400567) is a randomised, parallel, non-comparative phase II study. Patients with ER-positive, HER2-negative, Prosigna®-defined luminal B, or luminal A and node-positive, stage II-III breast cancer, not candidate for breast-conserving surgery, were randomly assigned to either letrozole (2.5 mg daily) and palbociclib (125 mg daily, 3 weeks/4) during 19 weeks, or to FEC100 (5FU 500 mg/m2, epirubicin 100 mg/m2, cyclophosphamide 500 mg/m2)×3 21-day courses followed by docetaxel 100 mg/m2×3 21-day courses. Primary end point was residual cancer burden (RCB 0-I rate). Secondary end points included clinical response, proliferation-based markers, and safety.

Results

Overall, 106 patients were randomised [median Prosigna® ROR Score 71 (22-93)]. RCB 0-I was observed in four and eight patients in LETPAL [7.7% (95% CI 0.4-14.9)] and chemotherapy [15.7% (95% CI 5.7-25.7)] arms, respectively. Pathological complete response rates were 3.8% and 5.9%. Clinical response (75%) and breast-conserving surgery rates (69%) were similar in both arms. Preoperative Endocrine Prognostic Index 0 scores (breast cancer-specific survival) were observed in 17.6% and 8.0% of patients in LETPAL and chemotherapy arms, respectively. Safety profile was as expected, with 2 versus 17 serious adverse events (including 11 grade 4 serious AEs in the chemotherapy arm).

Conclusion

LETPAL combination was associated with poor pathological response but encouraging clinical and biomarker responses in Prosigna®-defined high-risk LBC. Contemporary chemotherapy regimen was associated with poor pathological and biomarker responses, with a much less favourable safety profile. LETPAL combination might represent an alternative to chemotherapy in early high-risk LBC.

Clinical Trial Number

NCT02400567.

Employment two years after breast cancer diagnosis: role of household characteristics, CANTO cohort

Background

Breast cancer is associated with a high 5-year survival rate and more than half women are still of working age at diagnosis. Many studies evaluated the clinical determinants of return to work (RTW) but few investigated RTW in relation to family factors. Our objective was to study the role of household characteristics in non-RTW two years after breast cancerdiagnosis.

Methods

We used data of a French prospective cohort of women diagnosed with stage I-III, primary breast cancer (CANTO, NCT01993498). Patients had to be under 57 and have a job at diagnosis. We performed logistic regressions to model non-RTW two years after diagnosis in relation to household characteristics at diagnosis (marital status, children, support from partner), adjusting for tumor characteristics, health status at baseline and one year after diagnosis, and household income at diagnosis. In a second step, we conducted analyses stratified for household income at diagnosis.

Results

In total, 1874 women were eligible. Being in a relationship did not impact non-RTW (OR = 1.43 [95% CI 0.95-2.16]). Among the 1566 women in a relationship, being married was associated with elevated odds of non-RTW(OR = 1.37 [0.96-1.94]). Having children(OR = 1.17 [0.81-1.69]) or receiving support from their partner (OR = 1.17 [0.77-1.78]) was not associated with non-RTW. However, the situation differed in low-income households(&lt;2500€) among whom being married was associated with more elevated odds of non-RTW(OR = 1.94 [0.97-3.88]). No clear association was observed between having children (OR = 1.85 [0.85-4.03]) and non-RTW, but living with at least two children (OR = 2.76 [1.14-6.70]) and receiving support from their partner (OR = 2.28 [1.01-5.17]) was associated with increased odds of non-RTW.

Conclusions

The family environment is associated with non-RTW among the poorest women but not the others.

Key messages

Among the poorest women, the family environment is associated with non-RTW. Among all women, the family environment is not associated with non-RTW.

Identification of three subtypes of triple-negative breast cancer with potential therapeutic implications

Background

Heterogeneity and lack of targeted therapies represent the two main impediments to precision treatment of triple-negative breast cancer (TNBC), and therefore, molecular subtyping and identification of therapeutic pathways are required to optimize medical care. The aim of the present study was to define robust TNBC subtypes with clinical relevance.

Methods

Gene expression profiling by means of DNA chips was conducted in an internal TNBC cohort composed of 238 patients. In addition, external data (n = 257), obtained by using the same DNA chip, were used for validation. Fuzzy clustering was followed by functional annotation of the clusters. Immunohistochemistry was used to confirm transcriptomics results: CD138 and CD20 were used to test for plasma cell and B lymphocyte infiltrations, respectively; MECA79 and CD31 for tertiary lymphoid structures; and UCHL1/PGP9.5 and S100 for neurogenesis.

Results

We identified three molecular clusters within TNBC: one molecular apocrine (C1) and two basal-like-enriched (C2 and C3). C2 presented pro-tumorigenic immune response (immune suppressive), high neurogenesis (nerve infiltration), and high biological aggressiveness. In contrast, C3 exhibited adaptive immune response associated with complete B cell differentiation that occurs in tertiary lymphoid structures, and immune checkpoint upregulation. External cohort subtyping by means of the same approach proved the robustness of these results. Furthermore, plasma cell and B lymphocyte infiltrates, tertiary lymphoid structures, and neurogenesis were validated at the protein levels by means of histological evaluation and immunohistochemistry.

Conclusion

Our work showed that TNBC can be subcategorized in three different subtypes characterized by marked biological features, some of which could be targeted by specific therapies.

Electronic supplementary material

The online version of this article (10.1186/s13058-019-1148-6) contains supplementary material, which is available to authorized users.

Regulation of senescence escape by TSP1 and CD47 following chemotherapy treatment

Senescence is a tumor-suppressive mechanism induced by telomere shortening, oncogenes, or chemotherapy treatment. Although it is clear that this suppressive pathway leads to a permanent arrest in primary cells, this might not be the case in cancer cells that have inactivated their suppressive pathways. We have recently shown that subpopulations of cells can escape chemotherapy-mediated senescence and emerge as more transformed cells that induce tumor formation, resist anoikis, and are more invasive. In this study, we characterized this emergence and showed that senescent cells favor tumor growth and metastasis, in vitro and in vivo. Senescence escape was regulated by secreted proteins produced during emergence. Among these, we identified thrombospondin-1 (TSP1), a protein produced by senescent cells that prevented senescence escape. Using SWATH quantitative proteomic analysis, we found that TSP1 can be detected in the serum of patients suffering from triple-negative breast cancer and that its low expression was associated with treatment failure. The results also indicate that senescence escape is explained by the emergence of CD47^low cells that express a reduced level of CD47, the TSP1 receptor. The results show that CD47 expression is regulated by p21waf1. The cell cycle inhibitor was sufficient to maintain senescence since its downregulation in senescent cells increased cell emergence. This leads to the upregulation of Myc, which then binds to the CD47 promoter to repress its expression, allowing the generation of CD47^low cells that escape the suppressive arrest. Altogether, these results uncovered a new function for TSP1 and CD47 in the control of chemotherapy-mediated senescence.

Abstract PD2-03: Circulating tumor DNA (ctDNA) and circulating tumor cells (CTC) predictive value in HER2 negative metastatic breast cancer patients treated with first line weekly paclitaxel and bevacizumab: Results of a prospective cohort from the French Breast Cancer InterGroup Unicancer (UCBG): COMET study

Background: Increased levels of CTC and a persistent elevated level after just one cycle of chemotherapy are very strong and independent markers of worse progression-free survival (PFS) and overall survival (OS) in patients (pts) with metastatic breast cancer (MBC) (Bidard et al, Lancet Oncol 2014). ctDNA can be used to detect mutation associated with resistance to treatment. It has also been shown that dynamic changes in ctDNA levels closely reflect changes in tumor burden. We prospectively monitored CTC and ctDNA early variations during first line chemotherapy for MBC.

Patients & methods: The French cohort COMET is a prospective study including first line HER2 negative patients (pts) receiving weekly paclitaxel and bevacizumab according to EMA approved combination. The aim of this cohort is to evaluate clinical, biological and radiological parameters associated with pts outcome (CTC, serum markers, ctDNA, pharmacogenomic polymorphisms, metabolomic parameters, visceral fat, serum estradiol level and quality of life). We present here the first planned analysis on pts evaluated for CTC (CellSearch) and ctDNA using targeted sequencing (Roche SeqCap technology) of a panel of 46 genes and 8 promoters, using unique molecular identifiers to increase ctDNA detection sensitivity. Blood samples were obtained at baseline (BL) and before the second cycle of chemotherapy (C2).

Results: From 09/2012 to 5/2014, 218 pts were included in this substudy. Median age was 55 years and 22% of pts had triple negative BC. At BL, 70% of pts had ≥1 detectable CTC per 7.5 ml of blood (median 4 CTC, range 1- 30,000) and 37% at C2. With a threshold of ≥5 CTC, 47% of pts were positive at BL and 22% at C2. For ctDNA, out of the first 141 pts analyzed, 105 had at least one somatic mutation detected in plasma (74%). The average number of mutations per pt was 2.7 and most commonly mutated genes were TP53 and PIK3CA. ESR1 was found mutated in 9% of all cases and restricted to the ER+ subgroup. Median Allelic Frequency was 10% (range 0.6-83%). Only 33% of pts had detectable ctDNA at C2. At BL, CTC and ctDNA levels were correlated (r=0.46, p&lt;0.0001). Despite no complete overlap, 11% of pts had no CTC nor ctDNA detected. Median follow-up was 53 months and median OS was 32 months. Increased level of CTC and ctDNA were significantly associated with decreased PFS and OS. At C2, ≥5 CTC or still detectable ctDNA were strong markers of reduced OS: HR 4.6 (CI95 3.1-7) and HR 3.2 (CI95 1.8 – 5.5), respectively (both p&lt; 0.0001). At multivariate analysis for PFS, detectable ctDNA at C2 and triple negative status were the only significant prognostic factors. None of serum marker level at BL or their early variations had prognostic value.

Conclusion: This is the largest prospective cohort assessing the respective prognostic values of early CTC and ctDNA changes in homogenously treated first line MBC patients. Analysis of mutations profile variations and comparison with primary tumor and metastasis biopsies are ongoing and may reveal early mechanisms of resistance.

Citation Format: Pierga J-Y, Silveira A, Lorgis V, Tanguy M-L, Tredan O, Dubot C, Jacot W, Goncalves A, Debled M, Levy C, Ferrero J-M, Jouannaud C, Luporsi E, Mouret-Reynier M-A, Dalenc F, Lemonnier J, Berger F, Proudon C, Bidard F-C. Circulating tumor DNA (ctDNA) and circulating tumor cells (CTC) predictive value in HER2 negative metastatic breast cancer patients treated with first line weekly paclitaxel and bevacizumab: Results of a prospective cohort from the French Breast Cancer InterGroup Unicancer (UCBG): COMET study [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD2-03.

Abstract P4-15-02: TILs variations, proliferative response and PEPI scores in patients with luminal breast cancer receiving neoadjuvant letrozole-palbociclib or chemotherapy: An extended analysis of the NEOPAL trial

Background

The role of chemotherapy in early luminal breast cancer remains challenged. The NEOPAL trial (NCT 02400567; Cottu et al, ESMO 2017 LBA09) compared sequential chemotherapy (CT) and letrozole-palbociclib (LP) as neoadjuvant treatment in PAM50 defined high-risk luminal breast cancer patients, showing that LP might be as efficient as CT with regard to breast conserving surgery and pathological response. We report here extended exploratory pathological results, focusing on tumor infiltrating lymphocytes (TILs), proliferative response and preoperative endocrine prognostic index (PEPI) scores.

Material and Methods

Tumor blocks from baseline biopsy and surgical specimens were available for centralized review from the 106 randomized patients (53 in each arm). TILs quantification, KI67 staining and counting, and ER quantification were performed according to standard methods. Residual proliferative cancer burden (RPCB) and PEPI scores were computed according to published algorithms. Wilcoxon rank sum test and Mann Whitney test were used to compare paired and unpaired data. The chi-square and Fisher exact tests were used for categorical variables.

Results

Overall, median TILs count did not differ between LP and CT patients, both at baseline (p=0.37) and at the end of treatment (p=0.42). Median TILs count climbed from 5% (0-60) to 10% (1-60) in the LP arm (p=0.0026) and from 2% (0-30) to 10% (0-60) in the CT arm (p=0.0023). Median Ki67 dropped sharply in both arms, from 30% (1-80) to 1% (0-30) in the LP arm (p=1.10e-8) and from 30% (2-80) to 5% (0-30) in the CT arm (p=3.10e-9). Decrease in the Ki67 geometric mean was as sharp. Of note, while baseline Ki67 was similar in both arms (p=0.315), decrease in the LP arm was significantly more profound than in the CT arm (p=0.00075). Pathological response according to RPCB were as follows, in the LP and CT arm, respectively: class 0: 9.6%/10.2%; class I: 84.6%/73.5%; class II: 5.8%/16.3%. The relapse free survival PEPI scores were as follow in the LP and CT arm, respectively: class I: 13.5%/16.3%; class II: 59.6%/46.9%; class III: 28.9%/36.8% (p=0.504). Breast cancer specific survival PEPI scores were as follow in the LP and CT arm, respectively: class I: 18.9%/8.2%; class II: 54.7%/40.8%; class III: 26.4%/51%. These results were significantly better in the LP arm (p=0.027). There was no correlation between final TILs quantification and the RPCB or PEPI scores.

Conclusions

In this prospective multicenter study with centralized pathological review, neoadjuvant letrozole-palbociclib combination generates impressive proliferative and endocrine specific response features. It compared well with chemotherapy. The LP combination also significantly increased lymphocytic infiltration. Its clinical significance and utility remain to be elucidated, but it potentially adds new prognostic and theranostic information.

Citation Format: Vincent-Salomon A, Mathieu M-C, Bataillon G, Arnould L, Verrièle V, Ghnassia J-P, Haudebourg J, Penault-Llorca F, Lefebvre C, Maran-Gonzalez A, Guinebretière J-M, Duprez R, Berghian A, Blanc-Fournier C, Calès V, Galant C, Delrée P, Lemonnier J, Delaloge S, Cottu PH. TILs variations, proliferative response and PEPI scores in patients with luminal breast cancer receiving neoadjuvant letrozole-palbociclib or chemotherapy: An extended analysis of the NEOPAL trial [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-15-02.

Molecular profiling of hormone receptor-positive, HER2-negative breast cancers from patients treated with neoadjuvant endocrine therapy in the CARMINA 02 trial (UCBG-0609)

BACKGROUND

Postmenopausal women with large, hormone receptor (HR)-positive/HER2-negative and low-proliferative breast cancer derived a benefit from neoadjuvant endocrine therapy (NET) in the CARMINA02 trial. This study was designed to correlate gene expression and mutation profiles with both response to NET and prognosis.

METHODS

Gene expression profiling using RNA sequencing was performed in 86 pre-NET and post-NET tumor samples. Targeted next-generation sequencing of 91 candidate breast cancer-associated genes was performed on DNA samples from 89 patients. Molecular data were correlated with radiological response and relapse-free survival.

RESULTS

The transcriptional profile of tumors to NET in responders involved immune-associated genes enriched in activated Th1 pathway, which remained unchanged in non-responders. Immune response was confirmed by analysis of tumor-infiltrating lymphocytes (TILs). The percentage of TILs was significantly increased post-NET compared to pre-NET samples in responders (p = 0.0071), but not in non-responders (p = 0.0938). Gene expression revealed that lipid metabolism was the main molecular function related to prognosis, while PPARγ is the most important upstream regulator gene. The most frequently mutated genes were PIK3CA (48.3%), CDH1 (20.2%), PTEN (15.7%), TP53 (10.1%), LAMA2 (10.1%), BRCA2 (9.0%), MAP3K1 (7.9%), ALK (6.7%), INPP4B (6.7%), NCOR1 (6.7%), and NF1 (5.6%). Cell cycle and apoptosis pathway and PIK3CA/AKT/mTOR pathway were altered significantly more frequently in non-responders than in responders (p = 0.0017 and p = 0.0094, respectively). The average number of mutations per sample was significantly higher in endocrine-resistant tumors (2.88 vs. 1.64, p = 0.03), but no difference was observed in terms of prognosis. ESR1 hotspot mutations were detected in 3.4% of treatment-naive tumors.

CONCLUSIONS

The Th1-related immune system and lipid metabolism appear to play key roles in the response to endocrine therapy and prognosis in HR-positive/HER2-negative breast cancer. Deleterious somatic mutations in the cell cycle and apoptosis pathway and PIK3CA/AKT/mTOR pathway may be relevant for clinical management.

TRIAL REGISTRATION

This trial is registered with ClinicalTrials.gov ( NCT00629616 ) on March 6, 2008, retrospectively registered.

The 21-gene Recurrence Score® assay predicts distant recurrence in lymph node-positive, hormone receptor-positive, breast cancer patients treated with adjuvant sequential epirubicin- and docetaxel-based or epirubicin-based chemotherapy (PACS-01 trial)

Background

The 21-gene Recurrence Score (RS) result predicts outcome and chemotherapy benefit in node-negative and node-positive (N+), estrogen receptor-positive (ER+) patients treated with endocrine therapy. The purpose of this study was to evaluate the prognostic impact of RS results in N+, hormone receptor-positive (HR+) patients treated with adjuvant chemotherapy (6 cycles of FEC100 vs. 3 cycles of FEC100 followed by 3 cycles of docetaxel 100 mg/m²) plus endocrine therapy (ET) in the PACS-01 trial (J Clin Oncol 2006;24:5664-5671).

Methods

The current study included 530 HR+/N+ patients from the PACS-01 parent trial for whom specimens were available. The primary objective was to evaluate the relationship between the RS result and distant recurrence (DR).

Results

There were 209 (39.4%) patients with low RS (< 18), 159 (30%) with intermediate RS (18-30) and 162 (30.6%) with high RS (≥ 31). The continuous RS result was associated with DR (hazard ratio = 4.14; 95% confidence interval: 2.67-6.43; p <  0.001), adjusting for treatment. In multivariable analysis, the RS result remained a significant predictor of DR (p <  0.001) after adjustment for number of positive nodes, tumor size, tumor grade, Ki-67 (immunohistochemical status), and chemotherapy regimen. There was no statistically significant interaction between RS result and treatment in predicting DR (p = 0.79).

Conclusions

After adjustment for clinical covariates, the 21-gene RS result is a significant prognostic factor in N+/HR+ patients receiving adjuvant chemoendocrine therapy.

Trial registration

Not applicable.

Abstract P2-01-02: Heterogeneity and variability of human epidermal growth factor receptor 2 (HER2) expression on circulating tumor cells (CTC) in HER2 negative metastatic breast cancer patients treated with first line weekly paclitaxel and bevacizumab in a prospective cohort from the French Breast Cancer InterGroup Unicancer (UCBG): COMET study

Background: It has been reported in women with advanced estrogen-receptor (ER)-positive/(HER2)-negative breast cancer the acquisition of a HER2-positive CTC subpopulation during therapy (Jordan NV Nature 2016). The clinical significance of acquired HER2 heterogeneity during the evolution of metastatic breast cancer is unknown. We report here the analysis of HER2 status of CTC before and after one cycle of treatment in HER2 negative metastatic breast cancer patients treated with first line weekly paclitaxel and bevacizumab.

Patients & methods:The French cohort COMET is a prospective study including first line HER2 negative patients (pts) receiving weekly paclitaxel and bevacizumab according to EMA approved combination. The aim of this cohort is to evaluate clinical, biological and radiological parameters associated with pts outcome. We confirmed previously the outcome of patients with high CTC count at base line and after one cycle of treatment (Bidard et al, Lancet Oncol 2014). We present here the analysis on 203 pts evaluated for the expression of HER2 on CTC using the FDA cleared CellSearch method. The HER2 expression of CTCs (CB11 clone) was categorized (class 0–3) as described by Riethdorf et al.CCR2010.

Results: At base line, 144 out of 203 pts had at least one detectable CTC (71%), (median 4, and range 1- 30,000). Among them, 104 (72%) had one or more HER2 positive CTC (1-21,484). In 25 patients with HER2 2+ primary tumor with FISH or CISH non amplified, the incidence of CTC HER2+ cases (13/25, 52%) was similar than in pts with HER2 0 or HER2 1+ (51%) primary tumor. In each case, 3 to 100% of detectable CTC could be HER2+ stained (median 50% of CTC). Only 12 cases (8% of all CTC cases) had 2+ HER2 staining score on CTC and none 3+. After one cycle of treatment, the number of pts with detectable CTC dropped to 64, including 42 with HER2+ CTC (65%). Out of these cases, 14 were 3+ or 2+ HER2 score (22% of CTC+ cases). This was a significant increase compared to baseline (8%) (p&lt;0.001), including 6 cases with 100% of HER2+ CTC. To note, 7 patients without HER2+ CTC at baseline, had detectable HER2+ CTC after one cycle of treatment. With a median follow-up of 2 years, correlation of CTC variations with pts outcome is planned.

Conclusion: HER2 staining on CTC was heterogeneous with HER2 positive and negative subpopulations in the same patient with primary HER2 negative breast cancer. We observe a variability of HER2 CTC status with an increased intensity or appearance of immunostaining in few cases during treatment. We hypothesize that these phenotypes changes within patient-derived circulating tumor cells could contribute to progression of breast cancer and acquisition of drug resistance.

Citation Format: Pierga J-Y, Proudon C, Tredan O, Decraene C, Dubot C, Lorgis V, Jacot W, Goncalves A, Debled M, Levy C, Ferrero J-M, Jouannaud C, Luporsi E, Mouret-Reynier M-A, Dalenc F, Lemonnier J, Berger F, Bidard F-C. Heterogeneity and variability of human epidermal growth factor receptor 2 (HER2) expression on circulating tumor cells (CTC) in HER2 negative metastatic breast cancer patients treated with first line weekly paclitaxel and bevacizumab in a prospective cohort from the French Breast Cancer InterGroup Unicancer (UCBG): COMET study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-01-02.

Abstract P1-07-07: Overtime distribution and predictors of local recurrences (LRs) in patients with hormone receptor positive (HR+) and node positive (N+) breast cancers (BCs): 10 -year follow-up analysis of UNICANCER-PACS 01 and PACS04 trials

Purpose:Incidence of LRs in patients (pts) treated for HR+ HER2- localized BC and distribution overtime have not been described in recent years after introduction of new generation of adjuvant therapies and more extensive use of radiotherapy. We evaluated the incidence and distribution overtime of LRs in pts with HR+ HER2- N+ BCs who entered PACS 01 and PACS04 trials.

Patients and Methods: Data were analyzed from 2909 pts with HR+/HER2- BC out of 5008 included in both trials. Pts underwent mastectomy or lumpectomy plus axillary dissection for a localized N+ BC and, according to study design, were randomized to: 6 cycles of FE100C (standard arm) versus FE100C x 3 cycles followed by docetaxel 100 mg/m2 x 3 cycles (FEC-D) (PACS01) or 6 cycles of Epirubicin 75mg/m2 and Docetaxel 75 mg/m2 (ED75)(PACS04). Loco-regional radiotherapy was mandatory after lumpectomy and recommended in other cases. All pts received 5 years of hormone therapy (HT). A competing risk multivariate analysis was conduct using Fine and Gray model to identify risk factors associated to isolated LRs. Competing events were nodal recurrence, contralateral BC, distant metastasis and death. Cumulative incidence associated to each event was estimated by a Kablfleish-Prentice estimator.

Results: Pts' median age was 50 (22-65); 67.2% underwent lumpectomy, 32.8% mastectomy; 67.6% had 1 to 3 N+, 32.4% more than 3 N+; 45.7% had lymphovascular invasion; 49.5% received FE100C, 35.8% ET75, 14.7% had FEC-D; while radiotherapy was given to 97.3% and HT to 92.2%, of whom 90.5% received tamoxifen. At a median follow-up of 9.1 years, 60 pts (2.1%) experienced LR as first event. The 5-year and 10-year cumulative incidence of LRs were 1.04% and 2.53%, respectively. The cumulative incidence of LRs increased from the 5th year, and the annual risk tended to remain constant over time. Multivariate analysis of competing risk showed that younger age, conservative surgery and omission of HT (not prescribed or non-adherence) were independently associated with risk of developing LRs.

Table 1. Multivariate analysis on competing risk of predictors of LRsVariablesHR 95%CIP valueAge at entry (&lt;35 years, ≥ 35)*0.95 [0.92; 0.99]0.009Mastectomy, lumpectomy0.39 [0.17; 0.86]0.020&gt; 20mm, ≤20 mm0.68 [0.37; 1.24]0.203N+ &gt;3, 1-31.73 [0.99; 3.02]0.055Grade II/III, I1.06 [0.50; 2.24]0.885PR+,PR-1.78 [0.70; 4.53]0.223Type of chemotherapy 3FEC-3D, 6FEC/6ET1.32 [0.65; 2.69]0.446Number of cycles 6, &lt;60.71 [0.17; 0.75]0.630Hormone therapy Yes,No0.36 [0.17; 0.75]0.006*treated as continuous variable

Conclusion: Our analysis showed that incidence of LRs in pts with HR+ N+ BCs treated within PACS trials were considerably lower as compared to earlier studies. These findings may reflect differences in treatment era, as the more extensive use of radiotherapy and new generation of adjuvant chemotherapy. Despite current adjuvant strategies, young age at diagnosis and omission of HT remain independent risk factors of LRs.

Citation Format: Pistilli B, Filleron T, Mazouni C, Zingarello A, Lacroix-Triki M, Rivera S, Coudert B, Serin D, Canon J-L, Campone M, Bachelot T, Goncalves A, Levy C, Cottu P, Petit T, Eymard J-C, Tunon De Lara C, Roché H, Roca L, Lemonnier J, Delaloge S. Overtime distribution and predictors of local recurrences (LRs) in patients with hormone receptor positive (HR+) and node positive (N+) breast cancers (BCs): 10 -year follow-up analysis of UNICANCER-PACS 01 and PACS04 trials [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-07-07.

Abstract PD7-06: MAAT: Menses after adjuvant treatment. Prediction of menses recovery after chemotherapy for early breast cancer (BC) by using a nomogram model in UNICANCER PACS04 and PACS05 trials

Purpose:The likelihood of menses recovery (MR) is largely variable in premenopausal patients (pts) receiving adjuvant chemotherapy for BC. Quantifying this probability for each single patient could impact discussion of chemotherapy side effects and better individualize fertility counseling.We performed a pooled analysis from PACS04 and PACS05 randomized trials aiming to develop a nomogram to estimate the probability of menses recovery at 6 and 18 months (mos) after the end of adjuvant chemotherapy (CT) for premenopausal pts with early BC.

Patients and Methods: The analyzed population consisted of 1683 pts who were premenopausal and ≤ 50 (out of 4524 enrolled in both trials). In PACS05 node-negative BC pts were randomized to 4 or 6 cycles of FE100C (standard arm); in PACS04 node-positive pts were randomized to 6 cycles of FE100C or 6 cycles of Epirubicin 75mg/m2 and Docetaxel 75 mg/m2 (ED75). Endocrine therapy (ET) (Tamoxifen) x 5 years was mandatory for ER+ BC. Variables significantly associated with MR in the univariate analysis (P&lt;0.20) were included in the multivariate analysis. Using this data set, a logistic regression-based nomogram was developed to predict MR at 6 and 18 mos.

Results: Pts' characteristics were: median age 43 (22-50), median body mass index (BMI) at baseline 22.6 (15.6-54.7), at the end of chemotherapy 22.8 (15.8-58.6). ED75 was administrated to 517 (30.7%), while 802 (47.7%) received 6FE100C, 364 (21.6) 4FE100C. Trastuzumab was given to 122 (7.2%), ET to 1229 (73%) pts. CT-induced amenorrhea was observed in 1407 (83.6%) pts. Factors associated to MR were assessed on 1210 pts (excluding pts who recovered menses during CT or of whom date of recovery was not specified). At a median follow-up of 90 mos, 28.2% (342/1210) of pts had recovered menstrual cycles: 11% (133/1210) at 6 mos and 24.3% (294/1210) at 18 mos. Multivariate analysis showed that younger age, higher BMI at the end of CT, non-alkylating agents and absence of ET were independently associated to MR.

Table 1 Multivariate Cox regression analysis of menses recoveryVariablesHR (95%CI)P valueAge1.49 (1.16-1.93)&lt; 0.002Age2*0.99 [0.98-0.99]&lt;0.0001BMI after CT1.02 (0.99-1.04)0.07Alkylating agents0.72 (0.57-0.90)0.004Endocrine Therapy0.50 (0.40-0.62)&lt;0.001* The quadratic term in the age variable accounts for the non-linearity of the relation between the age and the probability of recovering menses. Overall this probability tend to decrease when age increase with a greater decrease for the older patients.

Nomogram concordance-index was 0.749 and 0.750 for predicting MR at 6 and 18 mos respectively. A better calibration was observed at 18 mos, comparing nomogram predictions with the actual probability of MR in the 1210 women.

Conclusion:Our analysis confirmed the possibility of developing a user-friendly nomogram for predicting menses recovery after adjuvant chemotherapy. As next step, we will externally validate our nomogram on CANTO premenopausal population, one of the biggest national cohorts aiming to assess the long-term impact of cancer treatments toxicities (UNICANCER NCT01993498 - http://etudecanto.org/).

Citation Format: Pistilli B, Mazouni C, Zingarello A, Faron M, Saghatchian M, Grynberg M, Spielmann M, Kerbrat P, Roché H, Lorgis V, Bachelot T, Campone M, Levy C, Goncalves A, Lesur A, Veyrat C, Vanlemmens L, Lemonnier J, Delaloge S. MAAT: Menses after adjuvant treatment. Prediction of menses recovery after chemotherapy for early breast cancer (BC) by using a nomogram model in UNICANCER PACS04 and PACS05 trials [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD7-06.

Abstract P3-13-02: Withdrawn

This abstract was withdrawn by the authors.