Effect of prior olaparib maintenance therapy for platinum sensitive recurrent ovarian cancer on response to subsequent platinum-based chemotherapy

Aim: Several years have passed since olaparib maintenance therapy was approved in patients with platinum sensitive recurrent ovarian cancer (PSROC). We speculated that the response to platinum-based chemotherapy (PBC) would be impaired at the time of recurrence after olaparib maintenance therapy. We conducted a noninterventional retrospective study to clarify this clinical question in a single institution. Methods: We included all patients with PSROC who received olaparib after second or later line of PBC between April 18, 2018, and August 31, 2021. We evaluated the effect of olaparib maintenance therapy on PBC after progression. Results: We identified 42 patients who received olaparib maintenance therapy after second or later line of PBC. Twenty-four patients relapsed after olaparib maintenance therapy, and 17 patients received PBC again. Four of 17 patients (complete response 2, partial response 2) responded to the PBC. The median progression-free survival was longer in patients with platinum-free interval ≥12 months than platinum-free interval of 6–12 months (9.7 vs 2.6 months, hazard ratio, 0.20: 95% confidence interval, 0.04–0.90; p = 0.04). Conclusions: In the patients with PSROC who experienced disease progression after olaparib maintenance therapy, especially in those with platinum-free interval of 6–12 months, the response to subsequent PBC was extremely poor. The efficiency of re-administration of PBC for PSROC patients with a short-term recurrence after olaparib treatment may need to be reconsidered.