Lurbinectedin, a selective inhibitor of oncogenic transcription, in patients with pretreated germline BRCA1/2 metastatic breast cancer: results from a phase II basket study

Abstract

Background: Lurbinectedin, a selective inhibitor of oncogenic transcription, has shown preclinical antitumor activity against homologous recombination repair-deficient models and preliminary clinical activity in BRCA1/2 breast cancer.

Patients and methods: This phase II basket multitumor trial (NCT02454972) evaluated lurbinectedin 3.2 mg/m2 1-h intravenous infusion every 3 weeks in a cohort of 21 patients with pretreated germline BRCA1/2 breast cancer. Patients with any hormone receptor and human epidermal growth factor receptor 2 status were enrolled. The primary efficacy endpoint was overall response rate (ORR) according to RECIST v1.1. Secondary endpoints included duration of response (DoR), progression-free survival (PFS), overall survival (OS) and safety.

Results: Confirmed partial response (PR) was observed in six patients [ORR = 28.6%; 95% confidence interval (CI) 11.3% to 52.2%] who had received a median of two prior advanced chemotherapy lines. Lurbinectedin was active in both BRCA mutations: four PRs in 11 patients (36.4%) with BRCA2 and two PRs in 10 patients (20.0%) with BRCA1. Median DoR was 8.6 months, median PFS was 4.1 months and median OS was 16.1 months. Stable disease (SD) was observed in 10 patients (47.6%), including 3 with unconfirmed response in a subsequent tumor assessment [ORR unconfirmed = 42.9% (95% CI 21.8% to 66.0%)]. Clinical benefit rate (PR + SD ≥ 4 months) was 76.2% (95% CI 52.8% to 91.8%). No objective response was observed among patients who had received prior poly (ADP-ribose) polymerase inhibitors. The most common treatment-related adverse events (AEs) were nausea (61.9%), fatigue (38.1%) and vomiting (23.8%). These AEs were mostly grade 1/2. The most common grade 3/4 toxicity was neutropenia (42.9%: grade 4, 23.8%: with no febrile neutropenia).

Conclusions: This phase II study met its primary endpoint and showed activity of lurbinectedin in germline BRCA1/2 breast cancer. Lurbinectedin showed a predictable and manageable safety profile. Considering the exploratory aim of this trial as well as previous results in other phase II studies, further development of lurbinectedin in this indication is warranted.

Keywords: BRCA1; BRCA2; breast cancer; lurbinectedin; phase II; response rate.

Conflict of interest statement

Disclosure VB received grants as consultant or advisory role from Puma Biotechnology, Ideaya Biosciences, Loxo Therapeutics, CytomX Therapeutics, Guidepoint, Oncoart; honoraria as speaker from Eli Lilly; and institutional financial support for clinical trials from AbbVie, ACEO, Adaptaimmune, Amcure, AMGEN, AstraZeneca, BMS Cytomx, GSK, Genentech/Roche, H3, Incyte, Janssen, Kura, Lilly, Loxo, Nektar, Macrogenics, Menarini, Merck, Merus, Nanobiotix, Novartis, Pfizer, PharmaMar, Principia, PUMA, Sanofi, Taiho, Tesaro, BeiGene, Transgene, Takeda, Incyte, Innovio, MSD, PsiOxus, Seattle Genetics, Mersana, GSK, Daiichi, Nektar, Astellas, ORCA, Boston Therapeutics, Dynavax, DebioPharm, Boehringer Ingelheim, Regeneron, Millennium, Synthon, Spectrum, Rigontec, and Zenith. BP received consulting fees from AstraZeneca and Pfizer for her institution and from Myriad and Pierre Fabre for herself; payment or honoraria for lectures, presentations, speakers bureaus or educational events from Daiichi-Sankyo, Novartis and Puma; support for attending meetings and/or travel from AstraZeneca, Pierre Fabre and MSD; and participation on a Data Safety Monitoring Board or Advisory Board from Novartis, Astra Zeneca and Daiichi-Sankyo. VM received grants or contracts as principal investigator or institutional funding from AbbVie, AceaBio, Adaptimmune, ADC Therapeutics, Aduro, Agenus, Amcure, Amgen, Astellas, AstraZeneca Bayer Beigene BioInvent International AB, BMS, Boehringer, Boheringer, Boston, Celgene, Daichii Sankyo, DEBIOPHARM,Eisai, e-Terapeutics, Exelisis, Forma Therapeutics, Genmab, GSK, Harpoon, Hutchison, Immutep, Incyte, Inovio, Iovance, Janssen, Kyowa Kirin, Lilly, Loxo, MedSir, Menarini, Merck, Merus, Millennium, MSD, Nanobiotix, Nektar, Novartis, Odonate Therapeutics, Pfizer, PharmaMar, Principia, PsiOxus, Puma, Regeneron, Rigontec, Roche, Sanofi, Sierra Oncology, Synthon, Taiho, Takeda, Tesaro, Transgene, Turning Point Therapeutics and Upshersmith; consulting fees from Roche, Bayer, BMS, and Janssen; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Roche, Bayer, BMS; and participation on a Data Safety Monitoring Board or Advisory Board from Basilea. CF, CK, VA, MS and AZ have personal fees for salary as full time employees from PharmaMar S.A. CF, CK, VA and AZ are stock ownership of PharmaMar S.A. FL received payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events, and support for attending meetings and/or travel, and participation on a Data Safety Monitoring Board or Advisory Board from Roche, Merck, Amgen, Lilly, Servier, MSD, BMS and Sanofi. AA received consulting fees from Gilead, Lilly and Seagen; payment for expert testimony from Pfizer; and leadership or fiduciary role in ECO Foundation. VS received grants from PharmaMar, Eli Lilly/LOXO Oncology, Blueprint Medicines Corporation, Turning Point Therapeutics and Boston Pharmaceuticals; and grants from Helsinn Pharmaceuticals during the conduct of the study; in addition, VS received a grant and advisory board/consultant position with Eli Lilly/Loxo Oncology during the conduct of the study; research grants from Roche/Genentech, Bayer, GlaxoSmithKline, Nanocarrier, Vegenics, Celgene, Northwest Biotherapeutics, Berghealth, Incyte, Fujifilm, D3, Pfizer, Multivir, Amgen, AbbVie, Alfa-sigma, Agensys, Boston Biomedical, Idera Pharma, Inhibrx, Exelixis, Blueprint Medicines, Altum, Dragonfly Therapeutics, Takeda, National Comprehensive Cancer Network, NCI-CTEP, University of Texas MD Anderson Cancer Center, Turning Point Therapeutics, Boston Pharmaceuticals, Novartis, PharmaMar and Medimmune; an advisory board/consultant position with Helsinn, Incyte, QED Pharma, Daiichi-Sankyo, Signant Health, Novartis, Relay therapeutics, Roche and Medimmune; travel funds from PharmaMar, Incyte, ASCO, ESMO; and other support from Medscape, all outside the submitted work. All other authors have declared no conflicts of interest. Data Sharing Individual participant data are not publicly available since this requirement was not anticipated in the study protocol considering that this trial started patient enrollment in 2015. Clinical trial summary results were placed in the European Clinical Trials Database (EudraCT; https://eudract.ema.europa.eu; study 2014-003773-42) and ClinicalTrials.gov (identifier: NCT02454972).

Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Figures

Figure 1

Changes in target lesion size and progression-free survival with lurbinectedin treatment in patients with germline BRCA1/2 metastatic breast cancer. (A) Waterfall plot showing maximum variation of target lesion size with lurbinectedin in patients with germline BRCA1/2 metastatic breast cancer. (B) Swimmer plot showing progression-free survival. Each bar represents a patient with germline BRCA1/2 metastatic breast cancer treated with lurbinectedin (n = 21). CT, chemotherapy; HR, hormone receptor; HER2, human epidermal growth factor receptor 2; PARPi, poly (ADP-ribose) polymerase inhibitor; PD, progressive disease; PFS, progression-free survival; PLAT, platinum; PR, partial response; SD, stable disease; TN, triple negative.