Merck announced positive results from the Phase 3 KEYNOTE-966 trial. In the final analysis of this trial, KEYTRUDA, Merck's anti-PD-1 therapy, in combination with standard of care chemotherapy (gemcitabine and cisplatin) demonstrated a statistically significant and clinically meaningful improvement in overall survival (OS) versus chemotherapy alone for the first-line treatment of patients with advanced or unresectable biliary tract cancer (BTC). The safety profile of KEYTRUDA in this trial was consistent with that observed in previously reported studies.

Results will be presented at an upcoming medical meeting and will be submitted to regulatory authorities. Merck has an extensive clinical development program evaluating KEYTRUDA in gastrointestinal cancers and is continuing to study KEYTRUDA for multiple uses in gastric, hepatobiliary, esophageal, pancreatic and colorectal cancers. KEYNOTE-966 is a randomized, double-blind Phase 3 trial (ClinicalTrials.gov, NCT04003636) evaluating KEYTRUDA in combination with gemcitabine and cisplatin compared to placebo plus gemcitabine and cisplatin for the first-line treatment of advanced and/or unresectable BTC.

The primary endpoint was OS, and the secondary endpoints included progression-free survival, objective response rate, duration of response and safety. The trial enrolled 1,069 patients who were randomized to receive KEYTRUDA (200 mg every three weeks for up to approximately two years) plus gemcitabine and cisplatin, or placebo plus gemcitabine and cisplatin. Biliary tract cancer is a group of rare and highly aggressive cancers in the gallbladder and bile ducts.

Biliary tract cancer is the second most common type of primary liver cancer after hepatocellular carcinoma, accounting for 15% of all liver cancers. It is estimated there are approximately 211,000 new cases of BTC diagnosed and 174,000 deaths from the disease each year globally. Biliary tract cancer is most frequently diagnosed in patients between 50 to 70 years old, and 70% of BTC patients are diagnosed at an advanced stage.

Patients diagnosed with BTC face a very poor prognosis, as the five-year survival rate is estimated to be between 5% and 15%. KEYTRUDA is an anti-programmed death receptor-1 (PD-1) therapy that works by increasing the ability of the body's immune system to help detect and fight tumor cells. KEYTRUDA is a humanized monoclonal antibody that blocks the interaction between PD-1 and its ligands, PD-L1 and PD-L2, thereby activating T lymphocytes which may affect both tumor cells and healthy cells.