Sumit K. Subudhi, MD, PhD
The combination of nivolumab (Opdivo) plus ipilimumab (Yervoy) demonstrated activity in a biomarker-enriched population of patients with metastatic castration-resistant prostate cancer (mCRPC); however, researchers need to refine the toxicity profile, said Sumit K. Subudhi, MD, PhD.
In the phase II CheckMate-650 trial (NCT02985957), results of which were presented at the 2019 Genitourinary Cancers Symposium, overall response rates (ORR) with the immunotherapy combination were 25% in asymptomatic and minimally symptomatic patients who progressed after second-generation hormonal therapy and had not received chemotherapy (cohort 1) and 10% in patients who progressed after taxane-based chemotherapy (cohort 2).
In the trial, patients received nivolumab at 1 mg/kg plus ipilimumab at 3 mg/kg every 3 weeks for 4 doses, then nivolumab at 480 mg every 4 weeks. Results showed that in both cohorts, the ORR was higher in patients with PD-L1 expression ≥1%, DNA damage repair, homologous recombination deficiency, and tumor mutational burden (TMB) above the median (74.5 mutations/patient). Of all prostate-specific antigen (PSA)-responding patients, 4 had PSA <0.2 ng/mL.
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