FDA approves Keytruda for solid tumors with high MSI or MMR deficiency: https://www.fda.gov/Drugs/InformationOnDrugs/ApprovedDrugs/ucm560040.htm On May 23, 2017, the U.S. Food and Drug Administration granted accelerated approval to pembrolizumab (Keytruda, Merck & Co.) for adult and pediatric patients with unresectable or metastatic, microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) solid tumors that have progressed following prior treatment and who have no satisfactory alternative treatment options or with MSI-H or dMMR colorectal cancer that has progressed following treatment with a fluoropyrimidine, oxaliplatin, and irinotecan. This is the FDA’s first tissue/site-agnostic approval. …The approval was based on data from 149 patients with MSI-H or dMMR cancers enrolled across five uncontrolled, multi-cohort, multi-center, single-arm clinical trials. Ninety patients had colorectal cancer and 59 patients were diagnosed with one of 14 other cancer types… The major efficacy outcome measures were objective response rate (ORR)…and response duration. …The identification of MSI-H or dMMR tumor status for the majority of patients (135/149) was prospectively determined using local laboratory-developed, investigational polymerase chain reaction (PCR) tests for MSI-H status or immunohistochemistry (IHC) tests for dMMR.