Key clinical point: Nivolumab plus ipilimumab demonstrated antitumor activity in chemotherapy-naive and chemotherapy-experienced patients with metastatic castration-resistant prostate cancer (mCRPC).

Major finding: Cohort 1 and cohort 2, respectively had objective response rate of 25% and 10%, median radiographic PFS of 5.5 and 3.8 months, median overall survival (OS) of 19.0 and 15.2 months and 12-month OS rate of 67% and 58%.

Study details: The data come from a preliminary phase 2 study of 90 patients with mCRPC who received nivolumab plus ipilimumab. Patients were categorized as chemotherapy naive (cohort 1; n = 45) and those who progressed on chemotherapy (cohort 2; n = 45).

Disclosures: The study was funded by Bristol Myers Squibb (BMS) and ONO Pharmaceutical Company Limited. M Ciprotti, B Simsek and Y Hu are employees of and shareholders in BMS. GC Han is an employee of BMS. A Saci is a former employee of and shareholder in BMS. The remaining authors reported ties with various pharmaceutical companies, including BMS.