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Sandy Srinivas, MD
Sandy Srinivas, MD
Posted: Tuesday, March 7, 2023
Eleni Efstathiou, MD, PhD, of Houston Methodist Cancer Center, and colleagues reported the results of the second interim analysis of the phase III MAGNITUDE study during the 2023 American Society of Clinical Oncology (ASCO) Genitourinary (GU) Cancers Symposium (Abstract 170). This trial, which evaluated the combination therapy of the PARP inhibitor niraparib plus abiraterone acetate and prednisone in patients with metastatic castration-resistant prostate cancer, followed up on previous results suggesting this regimen significantly improved outcomes among patients with homologous recombination repair (HRR) gene alterations.
“With 26.8 months of median follow-up, there was a statistically significant and meaningful clinical benefit in time to symptomatic [disease] progression and meaningful clinical benefit in time to cytotoxic chemotherapy,” concluded the investigators. “Taken together, these data continue to support the use of [this treatment] in patients with metastatic castration-resistant prostate cancer and BRCA alterations or select other homologous recombination repair gene alterations.”
This second interim analysis focused on 423 patients with metastatic castration-resistant prostate cancer who harbored HRR gene alterations. Participants were randomly assigned to receive abiraterone acetate and prednisone combined with niraparib (n = 212) or placebo (n = 211).
The updated radiographic progression–free survival was consistent with that of the primary analysis. Compared with placebo, the addition of niraparib extended the median progression-free survival from 10.9 to 19.5 months among patients with BRCA aberrations. Of note, there was an observed trend toward improved overall survival in this subgroup in both the primary stratified and multivariate analyses.
Furthermore, patients treated with niraparib reported a delayed time to worst pain intensity (hazard ratio [HR] = 0.70) and pain interference (HR = 0.67) compared with those on placebo. There were no new safety signals observed, and the safety profile at this second analysis was consistent with that of the primary analysis.
Disclosure: For full disclosures of the study authors, visit coi.asco.org.
2023 ASCO GU Cancers Symposium
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