Merck Co.'s Keytruda fails late-stage study in previously treated liver cancer patients

Merck & Co. on Tuesday announced data from the Phase III KEYNOTE-240 trial showing that its anti-PD-1 therapy Keytruda (pembrolizumab), plus best supportive care, did not meet its co-primary endpoints of overall survival (OS) and progression-free survival (PFS) versus placebo plus best supportive care in patients with advanced hepatocellular carcinoma (HCC) who were previously treated with systemic therapy. 

However, Roy Baynes, head of global clinical development and chief medical officer at Merck Research Laboratories, noted that the results for OS, PFS and objective response rate (ORR) were nevertheless "generally consistent" with findings from the Phase II KEYNOTE-224 study, which led to accelerated FDA approval of Keytruda last November for the treatment of patients with HCC previously treated with Bayer's Nexavar (sorafenib). 

In the KEYNOTE-240 trial, 413 patients with advanced HCC previously treated with systemic therapy were randomly assigned to treatment with Keytruda or placebo, both in combination with best supportive care. In addition to the primary endpoints of OS and PFS, secondary goals included ORR, duration of response, disease control rate and time to progression. 

Merck said that in the final analysis, improvements in favour of Keytruda were observed for both OS and PFS, but these differences did not reach statistical significance. The secondary endpoint of ORR was not formally tested because superiority was not achieved for OS and PFS. Meanwhile, the drugmaker noted that Keytruda's safety profile in KEYNOTE-240 was "consistent" with observations in previous studies, adding that results from the trial will be presented at a future research conference. 

The company recently reported that sales of Keytruda surged 66 percent to $2.2 billion in the quarter ended December 31. 

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