5533 Background: In Study 19 (NCT00753545), a RCT in 265 pts with PSR SOC, the oral PARP inhibitor olaparib significantly improved progression-free survival (PFS) vs placebo (PBO), with the greatest benefit seen in pts with a BRCA1/2 mutation ( BRCAm); an interim overall survival (OS) analysis suggested an advantage for olaparib-treated pts (DCO: Sep 30, 2015; Ledermann et al, 2016). We report a planned final analysis of the long-term benefit of olaparib in pts with PSR SOC in Study 19. Methods: Pts who had received ≥2 prior regimens of platinum-based chemotherapy and were in response to their most recent regimen received olaparib (400 mg bid; capsules) or PBO until disease progression. Retrospective germline or tumor testing resulted in a known BRCAm status for 254/265 pts (96%). Results: At final DCO (May 9, 2016) median OS follow-up was 78.0 months. A long-term treatment benefit and the final hazard ratio (HR) for OS vs PBO (unadjusted for crossover: 13% of PBO pts – full analysis set [FAS]; 23% of PBO pts – BRCAm subgroup) is shown (Table). Details of BRCAwt pts on treatment for ≥6 years will be presented. No new safety signals or changes in olaparib tolerability profile were seen. Conclusions: The Study 19 final analysis shows that olaparib provides clinically significant, long-term treatment benefit in pts with PSR SOC. A durable benefit was seen in ≥10% of BRCAm and BRCAwt pts, who continued to receive and benefit from olaparib for ≥6 years–unprecedented in the relapsed ovarian cancer setting. Olaparib is well tolerated in this pt population and the analysis suggests olaparib confers an OS benefit in BRCAm pts. Clinical trial information: NCT00753545. [Table: see text]
Long-term treatment with the PARP inhibitor niraparib does not increase the mutation load in cell line models and tumour xenografts
