Introduction/Background The efficacy of PARP inhibitors as maintenance therapy in platinum-sensitive recurrent ovarian cancer (ROC) has been well established, but the impact of dose modification on survival outcomes needs to be clarified.

An analysis of the SOLO2 trial demonstrated that dose reduction does not impact survival outcomes, but real-world data is missing.

We explored the effect of Olaparib dose reduction on progression-free survival (PFS) in the recurrence setting.

Methodology This retrospective study included BRCA 1/2 mutated ROC patients treated with Olaparib between 2019 and 2022 after complete or partial response to platinum-based chemotherapy. All patients started with the recommended dose of 600 mg daily. Patients were divided into 3 groups based on the number of dose reductions: no reduction (group 1); 1 dose reduction level (group 2); 2 dose reduction levels (group 3). PFS was estimated for patients who had not recurred within the first 12 weeks.

Results Of 81 patients identified, 32 (39.5%) had at least one dose reduction, and 44 (54.3%) had no dose modification. Patients who started maintenance treatment within 40 days from the last cycle of chemotherapy have a slightly lower risk of dose reduction (15/42, 35.7%) compared with those starting after 40 days (22/39, 56.4%) (p =0.062). There was no significant difference in PFS for patients who required at least one dose reduction compared to those not reducing at all (29 vs 30 months; log-rank p = 0.74). Similar results we found by analyzing median PFS according to dose reduction among the 3 groups (29 vs 30 vs 20 months in groups 1, 2 and 3, respectively, p = 0.89).

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Abstract #887 Figure 1

Conclusion Our analysis confirmed that almost half of the patients require Olaparib dose reduction without impacting survival expectations. These results can help physicians with patient counseling and management of adverse events, even in the first-line setting.

Disclosures None