Merck Updates Findings From Study Evaluating KEYTRUDA

(RTTNews) - Merck (MRK), known as MSD outside the United States and Canada, announced updated findings from a study evaluating KEYTRUDA (pembrolizumab), the company's anti-PD-1 therapy, in patients with advanced cancers characterized as deficient for DNA mismatch repair or MMR.

Results showed that among previously treated patients with MMR-deficient tumors, there was an overall response rate (ORR) of 53 percent (n=16/30) (95% CI, 36-70) in patients with a range of advanced non-colorectal solid tumors and an ORR of 57 percent (n=16/28) (95% CI, 39-73) in patients with advanced colorectal cancer; in contrast, no responses were observed in patients with advanced colorectal cancer whose tumors were characterized as MMR-proficient (n=0/25).

Merck conducted a phase 2 registration study (KEYNOTE-164) to evaluate the efficacy and safety of KEYTRUDA monotherapy in patients with previously treated, locally advanced unresectable or metastatic (Stage IV) MMR-deficient or microsatellite instability-high (MSI-H) colorectal cancer and a phase 3 study (KEYNOTE-177) in a treatment-naïve patient population. An additional phase 2 clinical trial (KEYNOTE-158) is evaluating patients with advanced tumors classified as MSI-H, excluding colorectal carcinoma.

The KEYTRUDA (pembrolizumab) clinical development program includes more than 30 tumor types in more than 270 clinical trials, including more than 100 trials that combine KEYTRUDA with other cancer treatments.

The phase 2 study evaluated the clinical activity of KEYTRUDA monotherapy (10 mg/kg every two weeks) in patients with previously treated, progressive metastatic disease with or without MMR-deficiency. Three groups were evaluated: MMR-deficient non-colorectal cancers (n=30), MMR-deficient colorectal cancer (n=28), and MMR-proficient colorectal cancer (n=25). MMR status was assessed locally using a standard immunohistochemistry (IHC) or polymerase chain reaction (PCR)-based method for detection of microsatellite instability. The key endpoints of the study were ORR, duration of response (DOR), progression-free survival (PFS) measured by RECIST v1.1, and overall survival (OS).