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A Phase III Study of Pembrolizumab Immunotherapy versus Chemotherapy for Metastatic Colorectal Cancer

Full Title

177-00: A Phase III Study of Pembrolizumab (MK-3475) vs. Chemotherapy in Microsatellite Instability-High (MSI-H) or Mismatch Repair Deficient (dMMR) Stage IV Colorectal Carcinoma (KEYNOTE-177)


The purpose of this study is to compare the effectiveness of pembrolizumab immunotherapy with standard chemotherapy in patients with metastatic colorectal cancer that contains certain genetic features. Pembrolizumab works by boosting the power of the immune system to find and destroy cancer cells. It does this by taking the brakes off certain proteins that inhibit the immune response. Pembrolizumab is used to treat several types of cancer; its use in this study is considered investigational.

Patients in this study will be randomly assigned to receive either pembrolizumab or standard chemotherapy (FOLFOX, FOLFIRI, bevacizumab, or cetuximab). All of the medications used in this study are given intravenously (by vein).


To be eligible for this study, patients must meet several criteria, including but not limited to the following:

  • Patients must have metastatic colorectal cancer that is “microsatellite instability-high” or “mismatch repair deficient.”
  • Patients may not have had prior chemotherapy for metastatic colorectal cancer. At least 6 months must pass between the completion of prior therapy for nonmetastatic disease and entry into the study.
  • For patients who had radiation therapy, at least 4 weeks must pass between the completion of that treatment and entry into the study.
  • Patients must be physically well enough that they are fully ambulatory, capable of all self care, and are capable of all but physically strenuous activities. As an example, patients must be well enough that they would be able to carry out office work or light housework.
  • This study is for patients age 18 and older.

For more information about this study and to inquire about eligibility, please contact Dr. Luis Diaz at 646-888-4204.






Diaz, Luis, MD