May 9 (Reuters) - Merck ( MRK ) said on Thursday its

therapy did not meet the main goal of disease-free survival in

certain patients with endometrial cancer during a late-stage

trial.

The drugmaker's Keytruda therapy in combination with

chemotherapy was being evaluated in patients with high-risk

endometrial cancer after surgery.

The study's other main goal of overall survival was not

formally tested since the trial failed in showing significant

disease-free survival.

Endometrial cancer begins in the inner lining of the uterus,

or endometrium, and is the most common type of the disease

affecting the organ.