KEYTRUDA ® is an anti-PD-1 therapy that works by helping increase the ability of the body's immune system to help detect and fight tumour cells. 1 An estimated 26,900 Canadians were diagnosed with colorectal cancer in 2020, with an average of 73 Canadians diagnosed daily. 2 KIRKLAND, QC, March 8, 2021 /CNW/ - Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced that Health Canada has approved KEYTRUDA ® (pembrolizumab), Merck's anti-PD-1 therapy, for the first-line treatment, as monotherapy, for adult patients with metastatic microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) colorectal cancer (CRC). 3 "This approval offers a new first-line treatment option for patients with MSI-H/dMMR metastatic colorectal cancer," said Dr. Ron Burkes, Professor of Medicine, University of Toronto and Medical Oncologist, Mount Sinai Hospital.