Merck and Japan-based Eisai said on Friday a combination of their therapies failed to extend the lives of patients with a type of esophageal cancer in a late-stage trial. The trial was studying U.S. drugmaker Merck's blockbuster immunotherapy Keytruda and Eisai's Lenvima,

The unsuccessful Phase III results are the latest to suggest that the blockbuster cancer drug is finally bumping up against its limits after racking up around 50 approvals since getting its first FDA nod in September 2014.

Merck & Co. and Eisai have to deal with the reality that yet another phase 3 trial of their combination of Keytruda and Lenvima didn’t exactly go their way. | Merck & Co. and Eisai have to deal with the reality that yet another phase 3 trial of their combination of Keytruda and Lenvima didn’t exactly go their way.

Merck's blockbuster drug Keytruda and Eisai's cancer drug Lenvima, in combination with chemotherapy, failed to improve overall survival in patients with a type of esophageal cancer in a late-stage trial,

MSD and Eisai’s trial saw mixed success with its two primary endpoints, seeing success in progression-free survival, but missing out on overall survival.

Co., Inc. (NYSE:MRK) and Eisai Co., Ltd. (TYO:4523) have announced the latest outcomes from their Phase 3 LEAP-015 trial, which evaluated the efficacy of the combination therapy KEYTRUDA and LENVIMA for patients with advanced gastroesophageal adenocarcinoma.