Patient-reported outcomes (PRO) in patients (pts) with BRCA1/2-altered metastatic castration-resistant prostate cancer (mCRPC) receiving niraparib (NIRA) with abiraterone acetate and prednisone (AAP): Results from MAGNITUDE study.

Abstract

105 Background: MAGNITUDE, an international phase 3 randomized double-blind study, demonstrated that mCRPC pts with BRCA1/2 alterations receiving NIRA + AAP had significantly improved radiographic progression-free survival, and clinically relevant prolongations in time to symptomatic progression and time to cytotoxic chemotherapy compared with placebo (PBO) + AAP. Here, we report PRO results (pain, health-related quality of life [HRQoL], and side effect bother) in the BRCA1/2 subset of mCRPC pts in the final analysis of MAGNITUDE. Methods: Pts were screened prospectively for homologous recombination repair (HRR) gene alterations. Eligible pts had ECOG status ≤1 and a Brief Pain Inventory–Short Form (BPI-SF) worst pain score ≤3 (scale of 0-10), and were randomized 1:1 to NIRA + AAP or PBO + AAP orally daily in 28-day cycles. PRO assessments on day 1 of specified cycles included BPI-SF and Functional Assessment of Cancer Therapy–Prostate (FACT-P). Time to deterioration (TTD) in pain (BPI-SF worst, average, and pain interference, and FACT-P pain-related scale [PRS]) were compared between treatment arms using proportional hazards regression models. Changes from baseline in HRQoL (FACT-P total, scale of 0-156) were compared using repeated measures analysis, and side-effect bother was assessed in both arms as a single item from FACT-P (GP5). Results: PRO compliance for FACT-P and BPI-SF was >85% in 225 pts with BRCA1/2-altered mCRPC. At baseline, mean BPI-SF pain scores was 1.09 (SD, 1.57) in NIRA + AAP and 1.35 (SD, 1.98) in PBO + AAP. Mean FACT-P Total in NIRA + AAP and PBO + AAP was 116.33 (SD, 18.42) and 114.8 (SD, 18.9), respectively. Median TTD in BPI-SF worst pain, pain interference, average pain, and FACT-P PRS were numerically longer for NIRA + AAP vs. PBO + AAP (Table). Repeated measures results showed HRQoL was maintained on treatment for the BRCA subgroup with no clinically meaningful differences in the FACT-P total score over time or between treatment arms. Analysis of FACT-P item GP5 in the BRCA subset showed side effect bother was rated “not at all” or “a little bit” by 87% of NIRA + AAP and 92% of PBO + AAP subjects across treatment cycles. Conclusions: In pts with BRCA1/2-altered mCRPC, NIRA + AAP maintained HRQoL. Pts experienced minimal bother from side effects associated with treatment. These data further support the benefit-risk profile of NIRA + AAP for the treatment of mCRPC pts with BRCA1/2 alterations. Clinical trial information: NCT03748641 . [Table: see text]