Bristol-Myers Squibb has announced results from its pivotal trial CheckMate-650, which showed that Opdivo in combination with Yervoy provided a significant response in patients with metastatic castration-resistant prostate cancer.

The results showed that among 32 patients whose disease had progressed after second-generation hormone therapy and who had not received chemotherapy, the objective response rate (ORR) was 25%.

In a second cohort of patients, among 30 whose disease progressed after taxane-based chemotherapy, the ORR was 10%.

Across both cohorts, higher response rates were seen in certain patient sub-groups, including patients with high tumour mutational burden and patients with homologous recombination deficiency.

“The results from CheckMate -650 provide strong rationale for the development of combination immune checkpoint therapy for the treatment of prostate cancer, which is considered a cold tumour with few tumour-infiltrating lymphocytes,” said Padmanee Sharma, professor of Genitourinary Medical Oncology and Immunology at The University of Texas MD Anderson Cancer Center.

“The clinical results from this study are encouraging and provide the foundation to test the combination strategy in a larger cohort of patients.”

Opdivo is a programmed death-1 (PD-1) immune checkpoint inhibitor that is designed to uniquely harness the body’s own immune system to help restore anti-tumour immune response.

Prostate cancer is the second most frequently diagnosed cancer in men, with almost 1.28 million new cases diagnosed worldwide in 2018. Unlike many early-stage prostate cancers that need normal levels of testosterone to grow, castration-resistant prostate cancer (CRPC) continues to grow even when the amount of testosterone in the body is reduced to castrate levels.