New findings by researchers at Yale Cancer Center show the drug combination of nivolumab and rucaparib shows clinical activity for patients with chemotherapy-naïve, metastatic castration resistant prostate cancer (mCRPC). The findings are part of the CheckMate 9KD trial and will be presented on September 19, 2021, at the annual meeting of the European Society for Medical Oncology (ESMO).

“This is important data regarding the benefit of these two drugs as a treatment option for patients with advanced prostate cancer,” said Daniel P. Petrylak, MD, Professor of Medicine (Medical Oncology) and Urology and Co-Leader of the Cancer Signaling Research Program at Yale Cancer Center and lead author of the study. “We are always encouraged identifying new ways to battle this difficult to treat disease.”

Cohort A2 of the phase 2 CheckMate 9KD trial assesses the efficacy of nivolumab plus rucaparib for chemotherapy-naïve mCRPC patients. Nivolumab works by blocking a protein that stops the immune system from working properly and attacking cancer cells. Rucaparib stops the growth of cancer cells by blocking enzymes needed for cell growth. In this study, 71 patients received nivolumab plus rucaparib. The results showed a PSA response rate of 84.6% in patients with BRCA or breast cancer gene positive tumors.

“Longer follow-up is needed to better characterize the clinical benefits of adding nivolumab to rucaparib for patient treatment,” added Petrylak. “Our work continues as there are still many patients who need effective treatment options.”

Funding for the study was provided by Bristol Myers Squibb.