Randomized phase III trial on trabectedin (ET-743) single agent versus clinician’s choice chemotherapy in recurrent ovarian, primary peritoneal, or fallopian tube cancers of BRCA-mutated or BRCAness phenotype patients (MITO23).

Abstract

LBA5504

Background: Trabectedin demonstrated antitumor activity when administered as single agent in relapsed platinum sensitive ovarian cancer (OC), with an overall response rate (ORR) ranging from 26 to 43% and a median PFS of 5 months. In addition, trabectedin showed 39.4% RR, 4.5 months median progression free survival (PFS) and 18 months median overall survival (OS) in a single arm phase 2 trial in recurrent BRCA mutated and/or the BRCAness phenotype OC patients. Methods: In this open-label, phase III, randomized trial, we assigned recurrent OC patients harboring BRCA 1/2 mutations or with BRCAness phenotype (defined as patients who had received and responded to at least 2 previous platinum-based treatments) to receive trabectedin 1.3 mg/mq q 21d or physician’s choice chemotherapy (among carboplatin, gemcitabine, weekly paclitaxel, pegylated liposomal doxorubicine or topotecan). The primary endpoint was OS. Secondary endpoints were PFS, ORR and Duration of Response (DoR). The sample size was calculated based on the assumption that trabectedin would increase median OS from 10 to 15 months (two-sided log-rank test at the error alfa= 0.05 and a power of 80%). Medians and lifetables were computed using the Kaplan-Meier method and analyzed using the log-rank test. Cox proportional hazards model was used to assess the effect of treatment. Results: Two hundred and forty-four patients were randomized and analyzed based on the intent-to-treat principle. At a median follow up of 40 months, the median PFS was 4.4 and 4.9 months (HR= 1.03 p=0.848) and median OS was 17.9 and 15.8 months (HR=1.15 p=0.304), in the control and experimental arm, respectively. ORR was 20.2% in the group of patients receiving standard chemotherapies and 15.4% in the group of patients treated with trabectedin. No superior effect was reported for Trabectedin in the pre-specified sub-group analysis according to BRCA mutational status, type of chemotherapy and platinum-free interval. No new signal of toxicity were reported for all the chemotherapies employed. Conclusions: Trabectedin as single agent does not improve survival outcomes when compared to standard chemotherapy in BRCA mut and BRCAness phenotype OC patients. Clinical trial information: NCT02993705.