Merk & Co., Merck Sharpe & Dohme

Merck Sharpe & Dohme is setting its sights to expand Keytruda for the treatment of prostate cancer, developing it further as an already robust leader in lung cancer.

Merck is now currently moving ahead with three trials of the PD-1 inhibitor alongside AstraZeneca’s Lynparza (olaparib), chemotherapy, and anti-hormone drugs.

Details of its phase I/II KEYNOTE-365 trial showed that Keytruda improved the efficacy of Lynparza in patients with castration-resistant prostate cancer.

Lynparza is itself a PARP inhibitor not currently approved for prostate cancer but is making its way through later-stage trials – as well as chemotherapy with docetaxel and prednisone, and hormone therapy Xtandi (enzaluatamide).

The Keytruda and Lynparza trial itself showed that 12% of patients had a 50% or more greater reduction in PSA, a marker which is elevated in prostate cancer. The chemotherapy combination had a PSA rate of 31%, and Keytruda and Xtandi showed a 26% response rate.

Clinical endpoints were encouraging as six-month overall survival rates were 73%, 96% and 91% respectively in each treatment group.

Other competitors currently being tried for the treatment of prostate cancer are BMS’ Opdivo alongside Clovis Oncology’s PARP inhibitor Rubraca (rucaparib).