Efficacy of Chemotherapy Following Prior PARP-Inhibitor Treatment in Patients with Ovarian Cancer.

Purpose: Considering the current lack of consensus on post-poly (adenosine diphosphate-ribose) polymerase inhibitor (PARPi) treatment strategies, this study aimed to evaluate the efficacy of subsequent therapy and compare the outcomes of regimes in patients with recurrent ovarian cancer after PARPi treatment.

Materials and methods: This multi-center retrospective cohort study analyzed data on patients diagnosed with ovarian cancer between January 2012 and June 2023 who had previously used PARPi after first- to fourth-line platinum-based chemotherapy. The primary endpoint was progression-free survival (PFS), which was the interval between recurrence after using PARPi and subsequent recurrence in the case of recurrence.

Results: Of 318 patients, 147/318 (46.2%) recurred after the PARPi maintenance. Patients were categorized into groups based on subsequent therapy except non-treated (11/147, 7.5%): platinum-based chemotherapy (89/147, 60.5%), non-platinum-based chemotherapy (21/147, 14.3%), other treatments (26/147, 17.7%), and the median PFS (mPFS) for each group were 7.3, 4.8 and 11.4 months, respectively. Among the platinum-based chemotherapy group, the gemcitabine + carboplatin regimen demonstrated a longer mPFS (10.1 months) than the other regimens (6.6 months, p=0.0194). In non-platinum-based chemotherapy, no statistically significant differences were observed among the regimens. And, in the other therapy group, where the proportion of patients with oligometastasis was as high as 88.5%, no significant differences were observed among the therapies, including other modalities.

Conclusion: In the subsequent chemotherapy of recurrent ovarian cancer after platinum-based chemotherapy and PARPi, the gemcitabine + carboplatin regimen demonstrated a potential to delay recurrence more effectively compared to other therapies.