J Gynecol Oncol.  2022 Aug;33(S1):S6. 10.3802/jgo.2022.33.S6.

Efficacy and impact of PARPi monotherapy to subsequent platinum-based chemotherapy in BRCA1/2 mutant ovarian cancer patients with secondary platinum-sensitive relapse

• Kun S
• Ma Y
• Bu H
• Kong B

• KMID: 2537930
• DOI: http://doi.org/10.3802/jgo.2022.33.S6

Abstract

Objective
The therapeutic effect of poly(ADP-ribose) polymerase inhibitors (PARPi) monotherapy compared with platinum-based chemotherapy, and the impact to subsequent platinum-based chemotherapy after PARPi resistance were inconclusive.
Methods
BRCA1/2 mutant ovarian cancer patients with secondary platinum-sensitive relapse were included. The patients did not receive any maintenance regimen after first- and second-line platinum therapy, and the secondary platinum-free interval (PFI) was more than 6 months. Patients in study group were treated with PARPi monotherapy until disease progression, and patients in control group were treated with platinum-based chemotherapy.
Results
A total of 64 patients were retrospectively analyzed, including 31 (48.4%) in study group and 33 (51.6%) in control group. The objective response rate (77.4% vs. 84.0%; p=0.538) and median progression-free survival (8.6 vs. 11.1 months; p=0.679) were comparable. PARPi monotherapy significantly prolonged post-recurrent survival (PRS) (hazard ratio [HR]=0.35; p=0.024), and was the independent factor associated with PRS (HR=0.33; p=0.038) in multivariate analysis. The median time from treatment to first subsequent therapy or death (mTFST) of patients with platinum-based chemotherapy after PARPi progression and patients in control group with PFI ≥6 months after third-line platinum-based chemotherapy was comparable (mTFST: 7.5 vs. 7.1 months; p=0.800). Further survival analysis showed that PRS of patients with PARPi monotherapy were similar to patients with PFI ≥6 months after third-line platinum chemotherapy (HR=0.66; p=0.503), and superior to patients with PFI <6 months after third-line platinum chemotherapy (HR=0.15; p=0.009).
Conclusion
PARPi monotherapy was equivalent to platinum-based chemotherapy for BRCA1/2-mutated ovarian cancer patients with secondary platinum-sensitive recurrence, and could improve prognosis.