Express . . . Keytruda has been approved by the FDA for a first-line single drug for specific colorectal cancer patients, promising to change treatment patterns.

▎ the US FDA announced today that it has approved the extended indication of keytruda (pembrolizumab), a heavy-weight PD-1 inhibitor developed by MSD, as the first-line treatment for colorectal cancer patients with unresectable or metastatic microsatellite instability (MSI-H) or mismatch repair defect (dmmr).the press release points out that this is the first time that it has been approved to treat this patient population without chemotherapy.this is also the first-line immunotherapy approved based on MSI-H or dmmr biomarkers, which is another breakthrough in screening patients with molecular biological markers.about 5% of patients with metastatic colorectal cancer carry MSI-H or dmmr tumors.MSI-H and dmmr tumors carry a large number of gene mutations in their genomes due to the abnormal DNA repair mechanism in cells, which makes these tumors more sensitive to immune checkpoint inhibitors.keytruda enhances the anti-cancer response of human immune cells by blocking the PD-1 / PD-L1 signaling pathway.previously, it has been approved as a second-line therapy for MSI-H or dmmr solid tumors.recently, it has also been approved by FDA as a second-line therapy to treat solid tumor patients with high tumor mutation load (tmb-h).FDA approved the indication based on the results of a multicenter, open label, active controlled, randomized trial comparing keytruda with chemotherapy in 307 patients with MSI-H or dmmr metastatic colorectal cancer.the study showed a statistically significant improvement in progression free survival (PFS) in patients treated with keyruda as assessed by a blind independent review. The median PFS was 16.5 months in the keyruda group and 8.2 months in the standard treatment group.longer term analysis is needed to assess the impact on survival.keyruda reduced the risk of disease progression or death by 40% compared with chemotherapy."metastatic colorectal cancer is a serious and life-threatening disease with poor prognosis. However, the combination of chemotherapy and other biological agents has strong side effects," said Richard, director of FDA oncology center of excellence and acting director of cancer disease Office of drug evaluation and research center "Providing a non chemotherapy option for a specific patient is a noteworthy change in treatment patterns," said Dr. pazdur."References: [1] FDA approved first line immunity for patients with MSI-H / dmmr metastatic colonial cancer. Retrieved June 29, 2020, from FDA approved Merck's keytruda (pembrolizumab) for first line treatment of patients with refractory or metastatic MSI-H or dmmr colonial cancer. Retrieved June 29, 2020, from Note: the purpose of this article is to introduce the progress of medical and health research, not to recommend treatment options.if you need guidance on treatment plan, please go to a regular hospital.