RETROSPECTIVE RE-EVALUATION OF PLATINUM-FREE INTERVAL AND CHEMOTHERAPEUTIC EFFECT AGAINST SUBSEQUENT PLATINUM-CONTAINING CHEMOTHERAPY IN RECURRENT OVARIAN CANCER PATIENTS INITIALLY TREATED BY CHEMOTHERAPY WITH BEVACIZUMAB

Introduction/BackgroundIt is concerned that the tumor dormancy effect of bevacizumab might prolong disease-free interval (DFI) regardless of platinum sensitivity, and lead to poorer outcome especially for patients recurrent in partially platinum-sensitive period defined as platinum free interval (PFI) of 6 to 12 months. We retrospectively investigated the relevance of PFI and response rate for recurrent ovarian cancer patients after chemotherapy with concurrent and maintenance bevacizumab.MethodologyPatients received platinum-based chemotherapy for platinum sensitive recurrent epithelial ovarian, fallopian tube and/or primary peritoneal cancer between November 1, 2013, and December 31, 2019, who initially had been confirmed complete response after platinum-based therapy with concurrent and maintenance bevacizumab, were registered. The primary endpoint was to examine response rate to subsequent chemotherapy after various period of PFI. The relevance between response rate and PFI divided into three groups of 6≦PFI<12, 12≦PFI<24 and PFI≧24 was assessed using Cochran-Armitage test. The secondary endpoint was progression-free survival (PFS) after chemotherapy for first recurrence, estimated separately for each three groups using the Kaplan-Meier method and differences between each group were evaluated with log-rank test. A P value <0.05 was considered statistically significant.ResultsTotal of 77 patients’ data were analyzed and the median PFI until first recurrence was 12 months (range: 6–43). The response rate of subsequent chemotherapy for patients with PFI of 6≦PFI<12, 12≦PFI<24 and PFI≧24 were 42%, 65% and 80%, which presented linear fashion increase (P<0.05, Cochran-Armitage test). The results for partially platinum-sensitive patients were comparable to those of past reports. Median PFS among three groups were 11 months (95%CI: 8.4–13.5), 13 months (95%CI: 5.4–20.5) and 8 months (95% CI: 6.7–9.2) (P=0.107, log-rank test), respectively.ConclusionAlthough there was concern about prolongation of DFI unrelated to platinum sensitivity by adding bevacizumab for primary treatment, the relationship between PFI and response to subsequent platinum-based chemotherapy remained unchanged.DisclosuresN. Matsumura received grants support from AstraZeneca plc. and participate in speaker’s bureau sponsored by AstraZeneca plc., Takeda pharmaceutical Co., Ltd. and Chugai pharmaceutical Co., Ltd. K. Takehara received grants support and honoraria fees from Chugai pharmaceutical Co., Ltd. The other authors have no potential conflict of interest to report.