Efficacy of olaparib in advanced cancers with germline or somatic mutations in BRCA1, BRCA2, CHEK2 and ATM, a Belgian Precision tumor-agnostic phase II study

BACKGROUND

The Belgian Precision initiative aims to maximize the implementation of tumor-agnostic next-generation sequencing in patients with advanced cancer and enhance access to molecularly guided treatment options. Academic tumor-agnostic basket phase II studies are part of this initiative. The current investigator-driven trial aimed to investigate the efficacy of olaparib in advanced cancers with a (likely) pathogenic mutation (germline or somatic) in a gene that plays a role in homologous recombination (HR).

PATIENTS AND METHODS

This open-label, multi-cohort, phase II study examines the efficacy of olaparib in patients with an HR gene mutation in their tumor and disease progression on standard of care. Patients with a somatic or germline mutation in the same gene define a cohort. For each cohort, a Simon minimax two-stage design was used. If a response was observed in the first 13 patients, 14 additional patients were included. Here, we report the results on four completed cohorts: patients with a BRCA1, BRCA2, CHEK2 or ATM mutation.

RESULTS

The overall objective response rate across different tumor types was 11% in the BRCA1-mutated (n = 27) and 21% in the BRCA2-mutated (n = 27) cohorts. Partial responses were seen in pancreatic cancer, gallbladder cancer, endocrine carcinoma of the pancreas and parathyroid cancer. One patient with a BRCA2 germline-mutated colon cancer has an ongoing complete response with 19+ months on treatment. Median progression-free survival in responding patients was 14+ months (5-34+ months). The clinical benefit rate was 63% in the BRCA1-mutated and 46% in the BRCA2-mutated cohorts. No clinical activity was observed in the ATM (n = 13) and CHEK2 (n = 14) cohorts.

CONCLUSION

Olaparib showed efficacy in different cancer types harboring somatic or germline mutations in the BRCA1/2 genes but not in ATM and CHEK2. Patients with any cancer type harboring BRCA1/2 mutations should have access to olaparib.

Real-world clinical outcomes of patients with stage I HER2-positive breast cancer treated with adjuvant paclitaxel and trastuzumab

Up to 20% of breast cancer overexpress HER2 protein, making it a reliable target for antibody-based treatments. In early HER2-positive breast cancer avoiding anthracycline-based chemotherapy is a challenge. Based on the single-arm phase II APT trial results, adjuvant paclitaxel/trastuzumab is an accepted regimen for patients with stage I HER2-positive disease. In our retrospective study of 240 patients, the median tumor size was 12.0 mm (IQR 9 -15), and 204 (85%) had estrogen receptor-positive disease. After a median follow-up of 4.6 years, 3-year real-world disease-free survival, distant DFS, and overall survival were 98.8% (95% confidence interval (CI), 96.2-99.6), 99.2% (95% CI, 96.7-99.8), and 98.3% (95% CI, 96.2-99.6), respectively. In a real-world setting, an adjuvant paclitaxel/trastuzumab regimen was associated with low recurrence rates among women with stage I, HER2-positive breast cancer. Additionally, we reviewed other treatment optimization strategies attempted or ongoing in HER2-positive breast cancer.

Abstract P4-07-16: B-IMMUNE final analysis: a phase Ib/II study of durvalumab combined with dose-dense EC in a neoadjuvant setting for patients with locally advanced luminal B HER2(-) or triple negative breast cancers

Background: Neoadjuvant association of immune checkpoints inhibitors (ICI) and dose dense chemotherapy is promising for triple negative breast cancers (TNBC). However, response rates vary from one study to another. Timing, best chemotherapy partner and efficacy in less immunogenic breast cancer (BC), like luminal B tumors, should be further investigated. This study evaluates for TNBC and luminal B HER2(-) BC the neoadjuvant treatment with paclitaxel followed by a short combination of an anti-PD-L1 antibody with anthracyclines. Method B-IMMUNE (NCT03356860), a multicentric phase Ib/II prospective trial, included patients with stage I to III luminal B HER2(-) or TNBC treated with paclitaxel 80mg/m2 weekly from week 1 to 12 followed by 4 cycles of epirubicine 90mg/m2 and cyclophosphamide 600 mg/m2 (EC) Q2W in a neoadjuvant setting. Phase Ib evaluated a single infusion of durvalumab (anti-PD-L1) combined with the 3rd cycle of EC. Phase II evaluated infusions of durvalumab with the 1st and 3rd EC cycles. Surgery was planned 3 weeks after the last EC cycle. Primary objectives were safety and pathological complete response (pCR) rate compared to a historical control. Secondary endpoint was the overall response rate (ORR) based on breast MRI. Eleven patients were enrolled in a control arm without durvalumab, exclusively for translational research purposes. Based on a 2-stage Simon design with an α = 0.1 and β = 0.1, 22 TNBC patients were needed in the phase II to test a null hypothesis of 30% pCR rate against a one-side alternative of 60%, and 24 luminal B BC patients to test a null hypothesis of 15% pCR rate against a one-side alternative of 40% (including an additional accrual margin of 10% for eventual dropouts). At least 9 pCRs had to be observed among the first 20 evaluable TNBC patients and 6 among the first 22 evaluable luminal B patients to rule out the null hypothesis. Results This analysis concerns the 50 patients treated with the experimental treatment, 3 from the phase Ib and 47 from the phase II part. Median age was 51 y-old (31 to 72y), tumor subtypes were 24 TNBC, 25 Luminal B and one sarcoma excluded from the efficacy analysis. Seven (14%) patients had a stage I tumor, 17 (34%) a stage IIA, 13 (26%) a stage IIB, 8 (16%) a stage IIIA, 4 (8%) a stage IIIB and 1 (2%) a stage IIIC. Concerning safety, 232 AEs were reported on 39/50 patients and 34 (14,6%) were graded ≥ 3. The 5 most frequent all-grade AEs were fatigue (8,2%), diarrhea (5,6%), neutropenia (5,2%), anemia and nausea (4,3%). Most frequent grade 3 AEs were anemia and neutropenia (14,7%). Among 4 immune-related adverse events, all were thyroid disorders. One patient died 10 months after the end of treatment due to progressive disease in the liver. Forty-six of the 47 phase II patients were evaluable for efficacy. pCR was reported in 12/22 TNBC patients (55%) and 8/24 luminal B HER2(-) patients (33%). Subgroup analyses based on PD-L1 expression and TILs score are planned. Conclusions The B-IMMUNE study met its primary objective showing a significant improvement in pCR versus the historical control in both TNBC and in Luminal B HER2(-) BC cohorts with the addition of only 2 doses of durvalumab to the anthracyclines. The safety profile is comparable to those previously described with reported immune related adverse events limited to thyroid endocrine disorders.

Citation Format: Alix Devaux, Gabriela Beniuga, Claire Quaghebeur, Stéphanie Henry, Mieke Van Bockstal, Christine Galant, Paul Delrée, Jean-Luc Canon, Brigitte Honhon, Dominique Korman, Vincent Verschaeve, Christophe Lonchay, Sarah Lefevre, Lionel D’Hondt, Martine Berlière, Sophie Delmarcelle, Jean-Michel Mine, Timour Willems, Gebhard Müller, Nathalie Myant, Isabelle Bar, Sandy Haussy, Pierre G. Coulie, François P. Duhoux, Javier Carrasco. B-IMMUNE final analysis: a phase Ib/II study of durvalumab combined with dose-dense EC in a neoadjuvant setting for patients with locally advanced luminal B HER2(-) or triple negative breast cancers. [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 P4-07-16.

Abstract P2-01-04: Real-world clinical outcomes of patients with stage I HER2-positive breast cancer treated with adjuvant paclitaxel and trastuzumab

Background: One year of adjuvant trastuzumab with 12 cycles of weekly paclitaxel represents the standard of care for patients with pathological tumor size ≤2cm, node-negative, HER2-positive early breast cancer. Data supporting this indication derive from a single-arm, phase II trial that enrolled 410 patients in the United States only, where the 3 years invasive disease-free survival (DFS) rate was 98.7% (95% CI 97.6-99.8). Therefore, real-world data regarding the clinical outcomes of these patients are needed to confirm the efficacy and safety of this adjuvant anthracycline-free regimen in this population. Methods: We conducted a retrospective, observational, multicentric study to investigate survival outcomes of patients with stage I HER2-positive early breast cancer treated with adjuvant paclitaxel and trastuzumab in seven selected sites in two countries (Belgium and Italy). Eligible patients were men and women with early breast cancer of pathological tumor size between 5 and 20 mm, node-negative (N0 or N1mic), and treated with weekly adjuvant paclitaxel for 12 weeks and trastuzumab (6 mg/kg every 3 weeks administration for 1 year). Patients with a history of previous cancers were not included. The primary endpoint was disease-free survival (DFS) at 3 years from diagnosis. Thus, an optimal follow-up of 3 years from surgery was required. Baseline clinico-pathological characteristics, treatment data, disease recurrences and survival status were extracted from medical records. Survival analysis was performed using log-rank regression test. Results: Overall, 240 patients who received their adjuvant treatment between January 2014 and December 2018 were included in the analysis. The median age was 59.5 years (IQR 50.0-66.9), and 69.6% of patients were post-menopausal at the time of diagnosis. Seventy (31.8%) patients had hypertension and 20 (8.3%) had other cardiac comorbidities. Ductal carcinoma was the most represented histological type (86.3%). The median tumor size was 12mm (IQR 9-15), only seven (2.9%) patients had N1miC, and the majority of tumors (85.0%) were ER-positive. Breast-conserving surgery was performed in 80.8% of patients and 78.2% of patients had adjuvant radiotherapy. The median number of administrated cycles of weekly paclitaxel was 12 (range 1-12) and for trastuzumab 18 (range 1-19). Only one patient stopped trastuzumab prematurely because of safety reason. Aromatase inhibitors were the most frequently administered endocrine therapy (75.7% of patients with ER-positive disease). With a median follow-up of 4.7 (IQR 3.6-5.6) years, we observed a 3-year DFS rate of 98.8% (95% CI 96.2-99.6), with only three disease recurrences (one local and two distant) and four deaths (none of which was breast cancer related) during the duration of the follow-up. Conclusions: In this real-world clinical outcome of patients with stage I HER2-positive breast cancer treated with adjuvant trastuzumab and paclitaxel appeared excellent, with a 1.2% rate of recurrence at 3 years. Our data support the efficacy of an anthracycline-free regimen in this population. A longer follow-up will provide more mature data on overall survival and late relapses, especially in the ER-positive subgroup of patients.

Citation Format: Veronique Debien, Elisa Agostinetto, Marianna Sirico, Flavia Jacobs, Chiara Molinelli, Michel Moreau, Marianne Paesmans, Ugo De Giorgi, Armando Santoro, Donatienne Taylor, François P. Duhoux, Andrea Botticelli, Giacomo Barchiesi, Matteo Lambertini, Evandro de Azambuja, Martine Piccart. Real-world clinical outcomes of patients with stage I HER2-positive breast cancer treated with adjuvant paclitaxel and trastuzumab [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 P2-01-04.

PRECISION: the Belgian molecular profiling program of metastatic cancer for clinical decision and treatment assignment

PRECISION is an initiative from the Belgian Society of Medical Oncology (BSMO) in collaboration with several stakeholders, encompassing four programs that aim to boost genomic and clinical knowledge with the ultimate goal to offer patients with metastatic solid tumors molecularly guided treatments. The PRECISION 1 study has led to the creation of a clinico-genomic database. The Belgian Approach for Local Laboratory Extensive Tumor Testing (BALLETT) and GeNeo studies will increase the number of patients with advanced cancer that have comprehensive genotyping of their cancer. The PRECISION 2 project consists of investigator-initiated phase II studies aiming to provide access to a targeted drug for patients whose tumors harbor actionable mutations in case the matched drug is not available through reimbursement or clinical trials in Belgium.

MitoQ Prevents Human Breast Cancer Recurrence and Lung Metastasis in Mice

Simple Summary

Entry in the metastatic phase is often devastating for cancer patients. Metastases originate from metastatic progenitor cells that are selected in the primary tumor and which simultaneously possess several phenotypic capabilities, including migration, invasion, and clonogenicity. We previously provided in vitro evidence that these features are collectively enforced by mitochondrial superoxide in a paradigm where mitochondria act as metabolic sensors of the tumor microenvironment and produce subcytotoxic levels of superoxide to prime metastatic progenitor cells. We also showed that these metastatic traits can be collectively countered by MitoQ, a mitochondria-targeted antioxidant that selectively deactivates mitochondrial superoxide. Here, we further establish that MitoQ prevents primary tumor recurrence after surgery, tumor take and metastasis as a whole, notably in a model of human breast cancer in mice. Since MitoQ already successfully passed Phase I clinical trials, our findings support the development of this drug as a preventive treatment against breast cancer metastasis.

Abstract

In oncology, the occurrence of distant metastases often marks the transition from curative to palliative care. Such outcome is highly predictable for breast cancer patients, even if tumors are detected early, and there is no specific treatment to prevent metastasis. Previous observations indicated that cancer cell mitochondria are bioenergetic sensors of the tumor microenvironment that produce superoxide to promote evasion. Here, we tested whether mitochondria-targeted antioxidant MitoQ is capable to prevent metastasis in the MDA-MB-231 model of triple-negative human breast cancer in mice and in the MMTV-PyMT model of spontaneously metastatic mouse breast cancer. At clinically relevant doses, we report that MitoQ not only prevented metastatic take and dissemination, but also local recurrence after surgery. We further provide in vitro evidence that MitoQ does not interfere with conventional chemotherapies used to treat breast cancer patients. Since MitoQ already successfully passed Phase I safety clinical trials, our preclinical data collectively provide a strong incentive to test this drug for the prevention of cancer dissemination and relapse in clinical trials with breast cancer patients.

Safety of assisted reproductive techniques in young women harboring germline pathogenic variants in BRCA1/2 with a pregnancy after prior history of breast cancer

BACKGROUND

Knowledge is growing on the safety of assisted reproductive techniques (ART) in cancer survivors. No data exist, however, for the specific population of breast cancer patients harboring germline BRCA1/2 pathogenic variants.

PATIENTS AND METHODS

This is a multicenter retrospective cohort study across 30 centers worldwide including women diagnosed at ≤40 years with stage I-III breast cancer, between January 2000 and December 2012, harboring known germline BRCA1/2 pathogenic variants. Patients included in this analysis had a post-treatment pregnancy either achieved through use of ART (ART group) or naturally (non-ART group). ART procedures included ovulation induction, ovarian stimulation for in vitro fertilization or intracytoplasmic sperm injection, and embryo transfer under hormonal replacement therapy.

RESULTS

Among the 1424 patients registered in the study, 168 were eligible for inclusion in the present analysis, of whom 22 were in the ART group and 146 in the non-ART group. Survivors in the ART group conceived at an older age compared with those in the non-ART group (median age: 39.7 versus 35.4 years, respectively). Women in the ART group experienced more delivery complications compared with those in the non-ART group (22.1% versus 4.1%, respectively). No other apparent differences in obstetrical outcomes were observed between cohorts. The median follow-up from pregnancy was 3.4 years (range: 0.8-8.6 years) in the ART group and 5.0 years (range: 0.8-17.6 years) in the non-ART group. Two patients (9.1%) in the ART group experienced a disease-free survival event (specifically, a locoregional recurrence) compared with 40 patients (27.4%) in the non-ART group. In the ART group, no patients deceased compared with 10 patients (6.9%) in the non-ART group.

CONCLUSION

This study provides encouraging safety data on the use of ART in breast cancer survivors harboring germline pathogenic variants in BRCA1/2, when natural conception fails or when they opt for ART in order to carry out preimplantation genetic testing.

Impact of the line of treatment on progression-free survival in patients treated with T-DM1 for metastatic breast cancer

Background

Trastuzumab emtansine (T-DM1) is indicated as second-line treatment for human epidermal growth factor receptor 2 (HER2)-positive metastatic or unresectable locally advanced breast cancer, after progression on trastuzumab and a taxane-based chemotherapy.

We wished to determine if the line of treatment in which T-DM1 is administered has an impact on progression-free survival (PFS) and in particular, if prior treatment with capecitabine/lapatinib or pertuzumab modifies PFS of further treatment with T-DM1.

Patients and methods

We performed a multicenter retrospective study in 3 Belgian institutions. We evaluated PFS with T-DM1 in patients treated for HER2 positive metastatic or locally advanced unresectable breast cancer between January 1, 2009 and December 31, 2016.

Results

We included 51 patients. The median PFS was 9.01 months. The line of treatment in which T-DM1 (1st line, 2nd line, 3rd line or 4+ lines) was administered had no influence on PFS (hazard ratio 0.979, CI95: 0.835–1.143).

There was no significant difference in PFS whether or not patients had received prior treatment with capecitabine/lapatinib (9.17 vs 5.56 months, p-value 0.875).

But, patients who received pertuzumab before T-DM1 tended to exhibit a shorter PFS (3.55 months for T-DM1 after pertuzumab vs 9.50 months for T-DM1 without pretreatment with pertuzumab), even if this difference was not statistically significant (p-value 0.144).

Conclusion

Unlike with conventional chemotherapy, the line of treatment in which T-DM1 is administered does not influence PFS in our cohort of patients with advanced HER2-positive breast cancer.

Assessment of potential process quality indicators for systemic treatment of breast cancer in Belgium: a population-based study

BACKGROUND

Quality indicators (QIs) for the management of breast cancer (BC) have been published in Europe and internationally. In Belgium, a task force was established to select measurable process indicators of systemic treatment for BC, focusing on appropriateness of delivered care. The objective of this study was to evaluate the results of the selected QIs, both nationally and among individual centres.

PATIENTS AND METHODS

Female Belgian residents with unilateral primary invasive BC diagnosed between 2010 and 2014 were selected from the Belgian Cancer Registry database. The national number enabled linkage with the national reimbursement database, which contains information on all reimbursed medical procedures. A total of 12 process indicators were measured on the population and hospital level. Intercentre variability was assessed by median results and interquartile ranges.

RESULTS

A total of 48  872 patients were included in the study. QIs concerning specific BC subtypes only applied to patients diagnosed in 2014 (n = 9855). Clinical stage (cStage) I patients (n = 17 116) were staged with positron emission tomography/computed tomography. Among patients who were pT1aN0 human epidermal growth factor receptor 2 (HER2) positive (n = 47), 25.5% (n = 12) received adjuvant trastuzumab. Among patients with de novo metastatic luminal A/B-like HER2-negative BC (n = 295), 17.3% (n = 51) received upfront chemotherapy. (Neo)adjuvant chemotherapy was administered in 52.4% (n = 12 592) of operated women with cStage I-III, in 37.0% (n = 1270) of operated women with cStage I-III luminal A/B-like HER2-negative BC, and in 19.1% of operated women with cStage I luminal A/B-like HER2-negative BC. In the population of operated patients with cStage I-III, of those younger than 70 years that started adjuvant endocrine therapy (n = 3591), 81.7% (n = 2932) continued treatment for ≥4.5 years. Among patients in cStage I-III older than 70 years (n = 8544), 19.0% (n = 1622) received (neo)adjuvant chemotherapy, whereas among patients with cStage I-III luminal A/B-like HER2-negative BC (n = 1388), 13.0% (n = 181) received (neo)adjuvant chemotherapy. In patients with cStage I-II luminal A/B-like HER2-negative BC older than 70 years (n = 1477), 11.6% (n = 171) were not operated and received upfront endocrine treatment.

CONCLUSION

Well-considered QIs using population-based data can evaluate quality of care and expose disparities among treatment centres. Their use in daily practice should be implemented in all centres treating BC.

Safety of systemic anti-cancer treatment in oncology patients with non-severe COVID-19: a cohort study

Background

The viral pandemic coronavirus disease 2019 (COVID-19) has disrupted cancer patient management around the world. Most reported data relate to incidence, risk factors, and outcome of severe COVID-19. The safety of systemic anti-cancer therapy in oncology patients with non-severe COVID-19 is an important matter in daily practice.

Methods

ONCOSARS-1 was a single-center, academic observational study. Adult patients with solid tumors treated in the oncology day unit with systemic anti-cancer therapy during the initial phase of the COVID-19 pandemic in Belgium were prospectively included. All patients (n = 363) underwent severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) serological testing after the first peak of the pandemic in Belgium. Additionally, 141 of these patients also had a SARS-CoV-2 RT-PCR test during the pandemic. The main objective was to retrospectively determine the safety of systemic cancer treatment, measured by the rate of adverse events according to the Common Terminology Criteria for Adverse Events, in SARS-CoV-2-positive patients compared with SARS-CoV-2-negative patients.

Results

Twenty-two (6%) of the 363 eligible patients were positive for SARS-CoV-2 by RT-PCR and/or serology. Of these, three required transient oxygen supplementation, but none required admission to the intensive care unit. Hematotoxicity was the only adverse event more frequently observed in SARS-CoV-2 -positive patients than in SARS-CoV-2-negative patients: 73% vs 35% (P < 0.001). This association remained significant (odds ratio (OR) 4.1, P = 0.009) even after adjusting for performance status and type of systemic treatment. Hematological adverse events led to more treatment delays for the SARS-CoV-2-positive group: 55% vs 20% (P < 0.001). Median duration of treatment interruption was similar between the two groups: 14 and 11 days, respectively. Febrile neutropenia, infections unrelated to COVID-19, and bleeding events occurred at a low rate in the SARS-CoV-2-positive patients.

Conclusion

Systemic anti-cancer therapy appeared safe in ambulatory oncology patients treated during the COVID-19 pandemic. There were, however, more treatment delays in the SARS-CoV-2-positive population, mainly due to a higher rate of hematological adverse events.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08349-8.

Tumor sequencing is useful to refine the analysis of germline variants in unexplained high-risk breast cancer families

Background

Multigene panels are routinely used to assess for predisposing germline mutations in families at high breast cancer risk. The number of variants of unknown significance thereby identified increases with the number of sequenced genes. We aimed to determine whether tumor sequencing can help refine the analysis of germline variants based on second somatic genetic events in the same gene.

Methods

Whole-exome sequencing (WES) was performed on whole blood DNA from 70 unrelated breast cancer patients referred for genetic testing and without a BRCA1, BRCA2, TP53, or CHEK2 mutation. Rare variants were retained in a list of 735 genes. WES was performed on matched tumor DNA to identify somatic second hits (copy number alterations (CNAs) or mutations) in the same genes. Distinct methods (among which immunohistochemistry, mutational signatures, homologous recombination deficiency, and tumor mutation burden analyses) were used to further study the role of the variants in tumor development, as appropriate.

Results

Sixty-eight patients (97%) carried at least one germline variant (4.7 ± 2.0 variants per patient). Of the 329 variants, 55 (17%) presented a second hit in paired tumor tissue. Of these, 53 were CNAs, resulting in tumor enrichment (28 variants) or depletion (25 variants) of the germline variant. Eleven patients received variant disclosure, with clinical measures for five of them. Seven variants in breast cancer-predisposing genes were considered not implicated in oncogenesis. One patient presented significant tumor enrichment of a germline variant in the oncogene ERBB2, in vitro expression of which caused downstream signaling pathway activation.

Conclusion

Tumor sequencing is a powerful approach to refine variant interpretation in cancer-predisposing genes in high-risk breast cancer patients. In this series, the strategy provided clinically relevant information for 11 out of 70 patients (16%), adapted to the considered gene and the familial clinical phenotype.

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.

Abstract P6-17-32: Impact of the line of treatment on progression-free survival in patients treated with T-DM1 for metastatic breast cancer

Background Trastuzumab emtansine (T-DM1) is a monoclonal antibody targeting human epidermal growth factor receptor 2 (HER2) receptors, conjugated with a cytotoxic component (a microtubule inhibitor). It is indicated as second-line treatment for HER2-positive metastatic or unresectable locally advanced breast cancer, after progression on trastuzumab and a taxane-based chemotherapy.

In HER2-negative metastatic breast cancer, progression-free survival (PFS) declines with each line of therapy, while patients with HER2-positive disease receive the most lines of chemotherapy and the longest duration for every line. We wished to investigate whether the line of treatment in which T-DM1 is administered has an impact on PFS. We also wished to explore whether prior treatment with capecitabine / lapatinib or pertuzumab had an impact on PFS, as none of the patients included in the registration trial had received these treatments before their inclusion in the trial.

Methods This is a multicenter retrospective study performed in 3 Belgian institutions. All patients received T-DM1 for HER2 positive metastatic or unresectable locally advanced breast cancer. The primary outcome was PFS with T-DM1, defined as the period between the first administration of T-DM1 and the first radiological or clinical assessment demonstrating progression of the disease.

Results We included 51 patients. One patient had to be excluded from the analyses because she no longer had HER positive disease. The median PFS was 9.01 months. The line of treatment in which T-DM1 was administered had no influence on PFS (hazard ratio 0.976, CI95 0.835-1.142).

There was no statistically significant difference in PFS between patients who had not received capecitabine / lapatinib before T-DM1 and those who had (9.11 vs 8.91 months, p-value 0.466).

Median PFS was 10.07 months when T-DM1 was administered prior to pertuzumab, and 5 months when administered after pertuzumab. Patients who received pertuzumab before T-DM1 thus tended to exhibit a shorter PFS. However, this difference is not statistically significant (p-value 0.096).

Conclusions Unlike with conventional chemotherapy, the line of treatment in which T-DM1 is administered does not influence PFS in metastatic breast cancer patients.

Citation Format: Duhoux FP, Dufour V, van Maanen A, Berliere M, Taylor D, Canon J-L. Impact of the line of treatment on progression-free survival in patients treated with T-DM1 for metastatic breast cancer [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 P6-17-32.

Abstract PD1-08: Phase 1/1b study of novel oral selective estrogen receptor degrader (SERD) LSZ102 for estrogen receptor-positive (ER+) advanced breast cancer (ABC) with progression on endocrine therapy (ET)

Background: LSZ102 is an orally bioavailable SERD that inhibits ER gene transcription, induces receptor degradation, and blocks ER-dependent cell growth in preclinical models. This study is evaluating LSZ102 as a single agent and in combination with the CDK 4/6 inhibitor ribociclib (LEE011) or the PI3K inhibitor alpelisib (BYL719) in patients (pts) with ER+ ABC. The LSZ102 single agent data are presented below; combination data are not discussed.

Methods: In the dose-escalation phase evaluating single-agent LSZ102 (Arm A), pts (age ≥18 years; ECOG PS 0-1) with histologically confirmed ER+ ABC and progression on endocrine therapy (ET) received LSZ102. The starting dose was 200 mg once daily. The primary objective of Arm A was to characterize the safety and tolerability of LSZ102 and identify a recommended dose for expansion (RDE). Secondary objectives included preliminary antitumor activity and pharmacokinetics (PK).

Results: As of January 22, 2018, 57 pts were enrolled to Arm A (LSZ102 200 mg, n=4; 400 mg, n=6; 450 mg fasted, n=15; 450 mg with food, n=6; 600 mg, n=20; 900 mg, n=6). Median age was 60 years, 75% (n=43) of pts had an ECOG PS of 0, 56% (n=32) had received prior fulvestrant, and 58% (n=33) had received prior CDK4/6 inhibitors; median number of prior lines of therapy (all settings) was 6. At data cut-off, 48 pts had discontinued treatment, most (n=45, 94%) due to disease progression. Dose-limiting toxicities across treatment groups included diarrhea (2 pts in the 900-mg group), vomiting (1 pt in the 600-mg group), and AST and ALT elevation (1 pt in the 450-mg with food group). The most common treatment-related adverse events (AEs) in the treatment period were diarrhea (60%), nausea (56%), and vomiting (30%). In the treatment period, treatment-related grade 3 AEs (12%) were infrequent, and there were no such grade 4 events. Six pts (11%) required dose reduction due to AEs (nausea, vomiting or diarrhea); 4/6 of the dose reductions occurred at 900 mg. Preliminary PK assessment showed rapid absorption and dose-proportional increases in LSZ102 exposure; trough concentrations were above the predicted tumorostatic concentrations at doses of ≥400 mg. Based on PK results for the 450-mg fasted and fed cohorts, LSZ102 exposure does not appear to be affected by dosing with a regular meal. Evidence of ER modulation by immunohistochemistry was observed in paired baseline and on-treatment biopsies. 18F-fluoroestradiol positron emission tomography (FES-PET) analysis (n=6) demonstrated abrogation of FES-PET signal for pts in the 450-mg and 600-mg dose groups. Seventeen pts (29.8%) had a best response of stable disease, and 1 pt, who happened to be in the 600-mg group, achieved a partial response.

Conclusion: In heavily pretreated pts, LSZ102 was well tolerated, demonstrated antitumor activity, and achieved effective exposure levels based on PK and pharmacodynamics. Food intake did not appear to significantly alter the PK profile of LSZ102. Dose escalation for LSZ102 in combination with ribociclib or alpelisib is ongoing and will be reported in a future analysis. An update on the recommended single agent dose and schedule will be presented.

Citation Format: Jhaveri K, Curigliano G, Yap Y-S, Cresta S, Duhoux FP, Terret C, Takahashi S, Ulaner GA, Kundamal N, Baldoni D, Liao S, Crystal A, Juric D. Phase 1/1b study of novel oral selective estrogen receptor degrader (SERD) LSZ102 for estrogen receptor-positive (ER+) advanced breast cancer (ABC) with progression on endocrine therapy (ET) [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 PD1-08.

Abstract OT1-03-01: Phase 1/1b study of novel oral selective estrogen receptor degrader (SERD) LSZ102 in combination with alpelisib (BYL719) in estrogen receptor-positive (ER+), human epidermal growth factor receptor-2–negative (HER2–) advanced breast cancer (ABC) with progression on endocrine therapy (ET)

Background: Although ET remains the basis of therapy for ER+, HER2– ABC, treatment resistance frequently occurs. Novel strategies to target the receptor and/or alternative pathways to overcome therapeutic resistance are under investigation. LSZ102 is a novel, orally bioavailable, nonsteroidal SERD. Preclinically, LSZ102 inhibits ER gene transcription, induces receptor degradation, blocks ER-dependent cell growth, and has synergistic activity with the phosphoinositide 3-kinase (PI3K)-alpha inhibitor alpelisib (BYL719). The present study is evaluating the safety and tolerability of LSZ102 plus alpelisib in patients with ER+, HER2– ABC with progression on ET.

Trial Design: This phase 1/1b, open-label study is enrolling ˜18-30 patients (men and women of any menopausal status) in Arm C of the dose-escalation part of the study, which investigates the combination of LSZ102 and alpelisib; additional study arms will investigate LSZ102 as a single agent or in combination with ribociclib. Enrollment in Arm C started after identification of a safe and tolerable single-agent dose for LSZ102. Alpelisib dosing began at 200 mg/day and will not be escalated beyond the maximum tolerated dose (MTD) determined in the alpelisib single-agent arm of study CBYL719X2101 (400 mg/day). Dose escalation of alpelisib in combination with LSZ102 is guided by BLRM and integrates Cycle 1 DLT rates, lower grade and later cycle AE, PK, PD and preliminary activity to identify a recommended dose for expansion (RDE). Patients will receive treatment until disease progression, unacceptable toxicity, or withdrawal of consent. For inclusion in the study, patients must have histologically confirmed ER+, HER2– ABC and disease progression after ET for ABC or recurrence on/within 12 months of completion of adjuvant ET. In the escalation part of the study, patients are eligible regardless of PIK3CA status. Premenopausal women must receive concomitant treatment with a gonadotropin-releasing hormone agonist. Eligible patients must have adequate bone marrow and organ function, Eastern Cooperative Oncology Group performance status of 0 or 1, and have completed and recovered from acute toxicities of radiotherapy and/or prior anticancer therapy. Exclusion criteria include symptomatic central nervous system metastases, clinically significant cardiac disease or impaired cardiac function (including a QT interval corrected for heart rate using Fridericia's formula [QTcF] &gt;460 ms in women or &gt;450 ms in men), uncontrolled diabetes mellitus type II (or type I), and prior treatment with a PI3K inhibitor. The primary objectives are characterization of safety and tolerability for the combination and identification of a recommended dose. Secondary objectives include characterization of pharmacokinetic properties and pharmacodynamic effects. Recruitment for Arm C is ongoing. NCT02734615

Citation Format: Curigliano G, Cresta S, Yap Y-S, Juric D, Duhoux FP, Terret C, Takahashi S, Layman RM, Kundamal N, Baldoni D, Liao S, Crystal A, Jhaveri K. Phase 1/1b study of novel oral selective estrogen receptor degrader (SERD) LSZ102 in combination with alpelisib (BYL719) in estrogen receptor-positive (ER+), human epidermal growth factor receptor-2–negative (HER2–) advanced breast cancer (ABC) with progression on endocrine therapy (ET) [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 OT1-03-01.

Prevalence of pathogenic variants and variants of unknown significance in patients at high risk of breast cancer: A systematic review and meta-analysis of gene-panel data

BACKGROUND

Gene-panels are used to assess predisposition to breast cancer by simultaneous testing of multiple susceptibility genes. This approach increases the identification of variants of unknown significance (VUS) that cannot be used in clinical decision-making. We performed a systematic review of published studies to calculate the prevalence of VUS and pathogenic variants (PV) in routinely tested breast cancer susceptibility genes in patients at high risk of breast cancer.

METHODS

We comprehensively searched the literature using Medline through May 23, 2017 for studies conducting gene-panel testing on germline DNA of women with familial breast cancer and reporting on both PVs and VUSs. A meta-analysis of the collected data was carried out to obtain pooled VUS and PV prevalence estimates per gene using a generalized linear mixed model with logit link for binomial distribution.

RESULTS

Of 602 publications, 4 were eligible and included 1870 patients. The panels encompassed 4-27 considered genes. Overall, the estimated probability per gene of a PV and VUS was 55% (95% confidence interval (CI) 26%-81%) and 91% (95% CI 78%-97%), respectively (p =  0.0066). The estimated probability per patient of a PV and VUS was 8% (95% CI 1%-34%) and 23% (95% CI 7%-52%), respectively (p =  0.0052). The ratio of VUS to PV was highest in the mismatch repair genes MLH1, MSH2, MSH6, PMS2 (18.7), CDH1 (13.4) and ATM (9.5). Amongst the 1468 patients tested for BRCA1 and BRCA2, only these two genes had a VUS to PV ratio of less than one (0.2 and 0.6, respectively).

CONCLUSION

With the current panels, the probability of detecting a VUS is significantly higher than the probability of detecting a PV. Better classification of VUSs is therefore critical and requires gene-specific VUS-assessment in every future study of gene-panel testing in patients at high risk of breast cancer.

Abstract P5-21-04: Phase I/Ib study of the SERD LSZ102 alone or in combination with ribociclib in ER+ breast cancer

Background: LSZ102 is an orally bioavailable selective estrogen receptor degrader (SERD) that inhibits estrogen receptor (ER) gene transcription, induces receptor degradation, and blocks ER-dependent cell growth in preclinical models. This Phase I/Ib, open-label study is evaluating LSZ102 as a single agent and in combination with the CDK4/6 inhibitor ribociclib (LEE011) or the PI3K inhibitor alpelisib (BYL719) in patients (pts) with locally advanced/metastatic ER-positive (ER+) breast cancer (BC).

Methods: The primary objective is to characterize the safety and tolerability, and identify a recommended dose and regimen of LSZ102 alone (Arm A) or in combination with ribociclib (Arm B) or alpelisib (Arm C). Secondary objectives include evaluation of preliminary antitumor activity and pharmacokinetics (PK). Eligible pts (aged ≥18 yrs; ECOG PS 0-1) have histologically confirmed ER+ BC that has progressed after endocrine therapy.

Results: As of March 14, 2017, dose escalation evaluating 16 pts in Arm A (LSZ102 200 mg [n=4], 400 mg [n=6], and 600 mg [n=6]) had completed (median age 57.5 yrs; 81% ECOG PS 0; 63% received prior fulvestrant). Five pts (median age 59.0 yrs; 80% ECOG PS 0; 60% received prior fulvestrant) had enrolled in the first cohort of Arm B (LSZ102 200 mg QD + ribociclib 300 mg 3 weeks on/1 week off) with evaluation ongoing. Arm C (LSZ102 + alpelisib) had yet to open. As of March 14, 2017, 9/16 (56%) pts in Arm A had discontinued treatment, all due to progressive disease (PD); in Arm B all pts were still receiving treatment. There were no dose-limiting toxicities in either arm at the dose levels evaluated; dose escalation is ongoing. The most common drug-related adverse events (AEs) were diarrhea (Grade [Gr] 1: 7/16; Gr 2: 2/16 pts), nausea (Gr 1: 6/16; Gr 2: 2/16 pts), and vomiting (Gr 1: 3/16 pts) in Arm A, and hot flush, nausea, vaginal discharge (all Gr 1: 2/5 pts), thrombocytopenia (Gr 1: 1/5; Gr 2: 1/5 pts), and neutropenia (Gr 2: 1/5, Gr 3: 1/5 pts) in Arm B. There were no drug-related Gr 3/4 AEs reported in Arm A; in Arm B, Gr 3 neutropenia, leukopenia, and lymphopenia each occurred in 1/5 pts. Preliminary PK assessment showed single-agent LSZ102 exposure increased dose-proportionally from 200 to 600 mg QD. In combination with ribociclib, exposures were consistent with those of the single agent at the same dose. In Arm A, preliminary evidence of antitumor activity was observed. Efficacy data for Arms B and C were not available as of March 14, 2017. One pt, whose tumor harbored an ESR1 D538G mutation, had been treated with multiple prior therapies in the metastatic setting, including letrozole, exemestane, tamoxifen, exemestane + everolimus, and anastrozole, as well as fulvestrant for 120 days prior to PD, and letrozole + palbociclib for 94 days prior to PD. As of March 14, 2017, this pt had been on LSZ102 treatment (400 mg QD) for 167 days, with a best response of stable disease (14% reduction in sum of diameter of target lesions).

Conclusions: Oral single-agent LSZ102 appears well-tolerated, with a manageable safety profile. Preliminary data also suggest tolerability when combined with ribociclib. Preliminary evidence of single-agent antitumor activity was seen in heavily pretreated pts with ER+ BC in a post-fulvestrant setting.

Citation Format: Juric D, Curigliano G, Cresta S, Yap Y-S, Terret C, Duhoux FP, Takahashi S, Kundamal N, Bhansali S, Liao S, Crystal A, Jhaveri K. Phase I/Ib study of the SERD LSZ102 alone or in combination with ribociclib in ER+ breast cancer [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 P5-21-04.

Tumor lysis syndrome following trastuzumab and pertuzumab for metastatic breast cancer: a case report

Background

Tumor lysis syndrome is a rare and potentially fatal complication of oncologic treatments, especially in solid tumors. To the best of our knowledge, tumor lysis syndrome has never been reported after trastuzumab and pertuzumab combination therapy. Knowledge of risk factors and active prevention proceedings is of utmost importance to avoid fatal outcomes.

Case presentation

We present the case of a chemo-naive 58-year-old Belgian woman developing hypovolemic shock and multiple organ failure due to tumor lysis syndrome after a single dose of trastuzumab and pertuzumab in the context of the treatment of a metastatic breast cancer and resulting in fatal outcome despite optimal management.

Conclusions

Considering that targeted cancer therapies become increasingly effective, oncologists should be extremely cautious when treating patients at high risk of tumor lysis syndrome, even if they are not treated with cytotoxic chemotherapy, and determine appropriate prophylaxis.

Abstract P4-04-10: Early-stage breast carcinomas are infiltrated by oligoclonal T cell populations highly enriched relative to the blood

BACKGROUD: The immunogenicity of some human tumors towards T lymphocytes is well established. Recently, encouraging results have been obtained with immunotherapies inhibiting immune checkpoints in cancers such as melanoma, NSCLC and bladder cancer. Fewer studies explored these treatments in breast cancer (BC) as these tumors are often considered to be poorly immunogenic.

METHODS: We analysed the T cell receptor β-chains variable genes (TCRBV) repertoires of tumor-infiltrating T cells in 17 early BC. We looked for clonally amplified T cells as their presence is an expected consequence of tumor immunogenicity. RNA was extracted and reverse-transcribed from formalin-fixed, paraffin-embedded tumor tissues. A short random sequence was added to the cDNA and used as a unique molecular identifier (UMI) for each cDNA molecule. cDNA encoding TCRBV genes was then amplified and sequenced using high throughput sequencing. Usage of UMIs during this procedure strongly improved the accuracy of the analysis by avoiding amplification biases inherent to the construction of the TCRBV library and by allowing an absolute quantification of TCRBV mRNA molecules normalized with the RPP30 housekeeping gene. TCRBV sequences were aligned using IMGT/HighV-QUEST. The Simpson's index was used to evaluate TCRBV repertoires diversity (ranging from 0 = infinite diversity to 1 = no diversity). For 3 patients, the same procedure was applied on blood T cells collected a few days before tumor resection and the analysis was also carried out on 3 normal tissues obtained from breast reduction surgery.

RESULTS: T cell infiltration varied strongly from one tumor to another ranging from 5 to 2498 TCRBV/103 RPP30 mRNA molecules. TCRBV repertoires analysis indicated that infiltrated T cells corresponded to oligoclonal populations. We observed 3 clonotypes in the smaller repertoire and 74 in the largest one and the Simpson's index ranged from 0.01 to 0.65. Most tumors (16/17) contained at least one clonotype that made up ≥10% of the infiltrating T cells, with the highest observed proportions reaching 80%. Normal breast samples were infiltrated by a more diverse repertoire: 130 to 368 clonotypes were identified in those tissues and Simpson's index ranged from 0.002 to 0.008. Highest observed frequency among those clonotypes was 2%. For 3 BC patients, the frequencies of the most prevalent clonotypes in the tumor were compared to those of the same clonotypes in blood prior to surgery. These T cell clones were 250 to &gt;34000 times more frequent in the tumor than in the blood.

CONCLUSIONS: Some early BC are infiltrated by oligoclonal T cell populations that are highly enriched relative to the blood. Quantitative T cell repertoire analysis allows to distinguish 3 types of BC: (1) tumors without T cell infiltration, (2) tumors with a high T cell infiltration and a small T cell repertoire, and (3) tumors with a high T cell infiltration and a large repertoire. Our observations suggest that anti-tumor T cell responses are ongoing in some early BC and this warrants boosting such responses with immune checkpoint inhibitors in selected patients. T cell repertoire evaluation could be used as a predictive biomarker to identify patients who will benefit from this treatment.

Citation Format: Carrasco J, Schröder D, Coulie PG, Godelaine D, Berlière M, Theate I, Delrée P, Vannuffel P, Galant C, Duhoux FP, Machiels J-P, Canon J-L. Early-stage breast carcinomas are infiltrated by oligoclonal T cell populations highly enriched relative to the blood. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-04-10.

Somatic uniparental isodisomy explains multifocality of glomuvenous malformations

Inherited vascular malformations are commonly autosomal dominantly inherited with high, but incomplete, penetrance; they often present as multiple lesions. We hypothesized that Knudson's two-hit model could explain this multifocality and partial penetrance. We performed a systematic analysis of inherited glomuvenous malformations (GVMs) by using multiple approaches, including a sensitive allele-specific pairwise SNP-chip method. Overall, we identified 16 somatic mutations, most of which were not intragenic but were cases of acquired uniparental isodisomy (aUPID) involving chromosome 1p. The breakpoint of each aUPID is located in an A- and T-rich, high-DNA-flexibility region (1p13.1-1p12). This region corresponds to a possible new fragile site. Occurrences of these mutations render the inherited glomulin variant in 1p22.1 homozygous in the affected tissues without loss of genetic material. This finding demonstrates that a double hit is needed to trigger formation of a GVM. It also suggests that somatic UPID, only detectable by sensitive pairwise analysis in heterogeneous tissues, might be a common phenomenon in human cells. Thus, aUPID might play a role in the pathogenesis of various nonmalignant disorders and might explain local impaired function and/or clinical variability. Furthermore, these data suggest that pairwise analysis of blood and tissue, even on heterogeneous tissue, can be used for localizing double-hit mutations in disease-causing genes.