Veliparib with frontline chemotherapy and as maintenance in Japanese women with ovarian cancer: a subanalysis of efficacy, safety, and antiemetic use in the phase 3 VELIA trial

Background: The phase 3 VELIA trial evaluated veliparib with carboplatin/paclitaxel and as maintenance in patients with high-grade serous ovarian carcinoma. Methods: Patients with previously untreated stage III–IV high-grade serous ovarian carcinoma were randomized 1:1:1 to control (placebo with carboplatin/paclitaxel and placebo maintenance), veliparib-combination-only (veliparib with carboplatin/paclitaxel and placebo maintenance), or veliparib-throughout (veliparib with carboplatin/paclitaxel and veliparib maintenance). Randomization stratification factors included geographic region (Japan versus North America or rest of the world). Primary end point was investigator-assessed median progression-free survival. Efficacy, safety, and pharmacokinetics were evaluated in a subgroup of Japanese patients. Results: Seventy-eight Japanese patients were randomized to control (n = 23), veliparib-combination-only (n = 30), and veliparib-throughout (n = 25) arms. In the Japanese subgroup, median progression-free survival for veliparib-throughout versus control was 27.4 and 19.1 months (hazard ratio, 0.46; 95% confidence interval, 0.18–1.16; p = 0.1 [not significant]). In the veliparib-throughout arm, grade 3/4 leukopenia, neutropenia, and thrombocytopenia rates were higher for Japanese (32%/88%/32%) versus non-Japanese (17%/56%/28%) patients. Grade 3/4 anemia rates were higher in non-Japanese (65%) versus Japanese (48%) patients. Early introduction of olanzapine during veliparib monotherapy maintenance phase may help prevent premature discontinuation of veliparib, via its potent antiemetic efficacy. Conclusions: Median progression-free survival was numerically longer in Japanese patients in the veliparib-throughout versus control arm, consistent with results in the overall study population. Pharmacokinetics were comparable between Japanese and non-Japanese patients. Data for the subgroup of Japanese patients were not powered to show statistical significance but to guide further investigation.