Merck & Co Inc and Eisai Co Ltd said on Friday they were discontinuing a late-stage study of Keytruda plus Lenvima for the treatment of adults with unresectable or metastatic melanoma, as the trial did not show improvement in overall survival.

The decision to discontinue the trial was based on the recommendation of an independent data monitoring committee after an interim analysis, the companies said.

Improvement in overall survival was one of the study's dual main goals, according to Merck and Eisai.

An earlier interim analysis pertaining to the other main goal of progression-free survival had shown a statistically significant improvement in the Keytruda plus lenvima arm, compared with the Keytruda plus placebo arm, the companies said.

They also said another late-stage trial for Keytruda and Lenvima did not meet its main goal of overall survival for treating a type of colorectal or colon cancer.

Merck's blockbuster cancer drug Keytruda belongs to class of medicines called PD-1 inhibitors that work by increasing the ability of the body's immune system to help detect and fight tumor cells.

Eisai's Lenvima is a kinase inhibitor that blocks certain proteins from helping cancer cells grow and divide.

It is estimated there will be nearly 100,000 new cases diagnosed of melanoma, the most serious form of skin cancer, and about 8,000 deaths resulting from the disease in the U.S. in 2023, according to Merck.