FDA Approves Merck’s KEYTRUDA for First-Line Treatment of Patients With Unresectable or Metastatic MSI-H or dMMR Colorectal Cancer

Merck, known as MSD outside the United States and Canada, announced that the U.S. Food and Drug Administration (FDA) has approved KEYTRUDA, Merck’s anti-PD-1 therapy, as monotherapy for the first-line treatment of patients with unresectable or metastatic microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) colorectal cancer. The approval is based on results from the Phase 3 KEYNOTE-177 trial, in which KEYTRUDA significantly reduced the risk of disease progression or death by 40% (HR=0.60 [95% CI, 0.45-0.80; p=0.0004]) compared with chemotherapy, the current standard of care. In the study, treatment with KEYTRUDA also more than doubled median progression-free survival (PFS) compared with chemotherapy (16.5 months [95% CI, 5.4-32.4] versus 8.2 months [95% CI, 6.1-10.2]).

“Today’s approval has the potential to change the treatment paradigm for the first-line treatment of patients with MSI-H colorectal cancer, based on the important findings from KEYNOTE-177 that showed KEYTRUDA monotherapy demonstrated superior progression-free survival compared to standard of care chemotherapy,” said Dr. Roy Baynes, senior vice president and head of global clinical development, chief medical officer, Merck Research Laboratories. “Our commitment to pursuing biomarker research continues to help us bring new treatments to patients, particularly for those who have few available options.”

Immune-mediated adverse reactions, which may be severe or fatal, can occur with KEYTRUDA, including pneumonitis, colitis, hepatitis, endocrinopathies, nephritis and renal dysfunction, severe skin reactions, solid organ transplant rejection, and complications of allogeneic hematopoietic stem cell transplantation (HSCT). Based on the severity of the adverse reaction, KEYTRUDA should be withheld or discontinued and corticosteroids administered if appropriate. KEYTRUDA can also cause severe or life-threatening infusion-related reactions. Based on its mechanism of action, KEYTRUDA can cause fetal harm when administered to a pregnant woman. For more information, see “Selected Important Safety Information” below.

This approval was granted less than one month following the submission of a new supplemental Biologics License Application (sBLA), which was reviewed under the FDA’s Real-Time Oncology Review (RTOR) pilot program. This review also was conducted under Project Orbis, an initiative of the FDA Oncology Center of Excellence that provides a framework for concurrent submission and review of oncology drugs among its international partners. For this application, a modified Project Orbis was undertaken, and the FDA is collaborating with the Australian Therapeutic Goods Administration, Health Canada and Swissmedic on their ongoing review of the application.

“Patients with unresectable or metastatic MSI-H colorectal cancer have historically faced poor outcomes, and until today, chemotherapy-containing regimens were the only FDA-approved first-line treatment options,” said Luis A. Diaz, M.D., head of the division of Solid Tumor Oncology, Memorial Sloan Kettering Cancer Center. “In patients who were treated with KEYTRUDA and responded (n=67) in the KEYNOTE-177 trial, 43% of patients experienced a duration of response lasting two years or longer. This approval helps address the unmet need to provide a new monotherapy treatment option for patients.”