Merck & Co. can add another positive Phase 3 clinical trial to the long list of study successes for its top-selling cancer immunotherapy Keytruda, reporting Wednesday that adding the drug to chemotherapy extended survival in patients with a form of advanced bile duct cancer.
Alongside the good news, however, Merck announced another late-stage trial of Keytruda together with two other drugs failed to improve survival and delay tumor growth in patients with a certain type of prostate tumor. The Keytruda regimen was also associated with higher incidence of side effects and, as a result of both findings, Merck will discontinue the study.
“We are grateful to the patients and investigators for their participation in this study, and we will continue to advance our clinical development program to evaluate Keytruda-based combinations and novel candidates for patients with prostate cancer,” said Scot Ebbinghaus, vice president of clinical research at Merck Research Laboratories, in a statement on the prostate cancer trial result.
Merck is running two other mid-stage trials of Keytruda in prostate cancer, as well as another Phase 3 study. And, through its partnership with AstraZeneca, the drugmaker has been studying the companies’ drug Lynparza in the disease, too.
Merck plans to detail data from both of the Keytruda trials that read out Wednesday at upcoming medical meetings. In the case of the bile duct cancer results, it will also share data with regulators.
That latter study tested Keytruda in combination with standard of care chemo against chemo alone in people with biliary tract cancer that was either advanced or not removable through surgery. The trial was in the “first-line” setting, meaning participants had not been previously treated.
According to Eliav Barr, Merck Research Laboratories’ chief medical officer, five-year survival rates for patients diagnosed with advanced biliary tract cancer are only 5% to 15%.
Should the trial findings help Merck win an approval for Keytruda in the disease, it would add another indication to the drug’s label, which currently covers uses in 18 different types of cancer.
An approval would also mean Keytruda could compete with AstraZeneca’s immunotherapy Imfinzi, which won U.S. approval for advanced biliary tract cancer last September. Rival drugmaker Roche, meanwhile, is also studying its immunotherapy Tecentriq for treating the tumor type, and recently reported Phase 2 study results.
Of potentially more significance to Merck are pending results from a study of subcutaneously injected Keytruda in lung cancer. The data could help it win approval for a more convenient formulation of the drug than it’s current intravenous form, as well as potentially help protect sales following patent expirations later this decade.
Correction: This story has been updated to clarify the number of types of cancer Keytruda is approved to treat.