158MO - Niraparib with abiraterone acetate and prednisone (NIRA+AAP) as first-line therapy in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC) with homologous recombination repair (HRR+) gene alterations: Asian subgroup analysis of the MAGNITUDE study

Background

In the phase 3 MAGNITUDE study (NCT03748641), NIRA+AAP met the primary endpoint of radiographic progression-free survival (rPFS) and improved other clinically relevant outcomes in pts with HRR+ mCRPC. Here we report data from an Asian subgroup analysis of this study.

Methods

A subgroup analysis was conducted for the primary endpoint (rPFS by blinded independent central review [BICR]), secondary endpoints (time to cytotoxic chemotherapy [TTCC], time to symptomatic progression [TTSP], and overall survival [OS]), as well as time to prostate-specific antigen progression (TTPP), overall response rate (ORR), and safety in Asian pts with HRR+ mCRPC. Pts were enrolled at study sites in China, Korea, Malaysia, and Taiwan, and received NIRA 200 mg + AAP or placebo (PBO) + AAP daily.

Results

Sixty-eight Asian pts with HRR+ mCRPC (28 NIRA+AAP; 40 PBO+AAP) were assessed. Median age was 71 yr, 15% had prior AAP, 34% had visceral metastases, and 44% had BRCA2 mutations; no BRCA1 mutations were reported. Median follow-up was 17.7 mo. Improvement in rPFS by BICR was observed with NIRA+AAP vs PBO+AAP, with reduced risk of progression or death of 55% (median 22.0 vs 11.1 mo) (Table). NIRA+AAP delayed TTCC, TTSP and TTPP, and improved ORR. All P-values are nominal. OS data are immature. Grade 3/4 treatment-emergent adverse events (TEAEs) occurred in 68% of pts in the NIRA+AAP group (most commonly anemia [43%]) and 38% in the PBO+AAP group (most commonly alanine aminotransferase increased [13%]). Rates of TEAEs leading to discontinuation of at least one study drug were 11% with NIRA+AAP and 8% with PBO+AAP. Table: 158MO

^a10 events were reported with PBO+AAP and 0 events were reported with NIRA+AAP, resulting in an HR = 0.

Conclusions

Data from this Asian subgroup analysis of the MAGNITUDE study are aligned with the global results and support the benefit of NIRA+AAP in HRR+ mCRPC.

Clinical trial identification

NCT03748641.

Editorial acknowledgement

Medical writing assistance was funded by Janssen Global Services, LLC and provided by Jennifer A. DiNieri, PhD (System One).

Legal entity responsible for the study

Janssen Research & Development, LLC.

Funding

Janssen Research & Development, LLC.

Disclosure

M. Binti Saad: Financial Interests, Personal, Advisory Role: Johnson&Johnson, MSD, AstraZeneca, Novartis, Merck, Bristol Myers Squibb, Viatris, Ipsen; Financial Interests, Personal, Other, Honoraria: Astellas Pharma, Novartis, Johnson&Johnson, Ipsen, Cipla, AstraZeneca, Eisai, Pfizer, Amgen; Financial Interests, Personal, Research Grant: Johnson & Johnson, MSD. K.N. Chi: Financial Interests, Personal, Advisory Role: ESSA, Astellas Pharma, Janssen, Sanofi, Amgen, Bayer, AstraZeneca, Roche, POINT Biopharma, Daiichi Sankyo, Merck, Constellation Pharmaceuticals; Financial Interests, Personal, Expert Testimony: AstraZeneca, Novartis; Financial Interests, Personal, Other, Honoraria: Janssen, Astellas Pharma, Bayer, AstraZeneca, Roche, Merck; Financial Interests, Institutional, Research Grant: Janssen, Astellas Pharma, Bayer, Sanofi, Bristol Myers Squibb, Merck, Roche, AstraZeneca, Novartis, Pfizer, ESSA. G. Attard: Financial Interests, Personal, Advisory Role: Janssen-Cilag, Veridex, Ventana Medical Systems, Astellas Pharma, Medivation, Novartis, Millennium, Abbott Laboratories, ESSA, Bayer, Pfizer, AstraZeneca, Ferring; Financial Interests, Personal, Speaker’s Bureau: Janssen, Astellas Pharma, Takeda, Sanofi, Ventana Medical Systems, Ipsen, AstraZeneca, Ferring; Financial Interests, Personal, Other, Travel, Accommodations, Expenses: Janssen, Astellas Pharma, Medivation, Ventana Medical Systems, Abbott Laboratories, Bayer, ESSA, Pfizer, Ferring; Financial Interests, Personal, Other, Travel, Accommodations, Expenses, Immediate Family Member: Janssen, Astellas Pharma; Financial Interests, Personal, Other, Patents, Royalties, Other Intellectual Property: Institute of Cancer Research; Financial Interests, Personal, Other, Honoraria: Janssen, Astellas Pharma; Financial Interests, Personal, Other, Honoraria, Immediate Family Member: Janssen; Financial Interests, Institutional, Research Grant: Janssen, Arno Therapeutics, Innocrin Pharma. S.K. Sandhu: Financial Interests, Institutional, Advisory Role: AstraZeneca, Merck Sharp & Dohme, Bristol Myers Squibb/Roche; Financial Interests, Personal, Speaker’s Bureau: Bristol Myers Squibb, Merck, Roche/Genentech; Financial Interests, Institutional, Other, Honoraria: Bristol Myers Squibb, Merck, Merck Serono, AstraZeneca; Financial Interests, Institutional, Research Grant: Amgen, AstraZeneca, Merck, Endocyte/Advanced Accelerator Applications, Genentech/Roche, Novartis. G.E. Mason: Financial Interests, Personal, Full or part-time Employment: Janssen Research & Development; Financial Interests, Personal, Other, Full or Part-time Employment, Immediate Family Member: Merck; Financial Interests, Personal, Other, Travel, Accommodations, Expenses: Janssen Research & Development; Financial Interests, Personal, Stocks/Shares: Johnson & Johnson; Financial Interests, Personal, Other, Stocks/Shares, Immediate Family Member: Merck. A. del Corral: Financial Interests, Personal, Full or part-time Employment: Janssen (Johnson & Johnson); Financial Interests, Personal, Stocks/Shares: Amgen, Bristol Myers Squibb/Celgene, Ecolab Inc, Edwards Lifesciences, Intuitive Surgical, Johnson & Johnson/Janssen, Lilly. G. Wang, D. Wu, B. Diorio, A. Lopez-Gitlitz: Financial Interests, Personal, Full or part-time Employment: Janssen (Johnson & Johnson); Financial Interests, Personal, Stocks/Shares: Janssen (Johnson & Johnson). All other authors have declared no conflicts of interest.