How FDA Approved KEYTRUDA for All Solid Tumors based on MSI status

In 2017, FDA approved KEYTRUDA for all solid cancers based on LDT "MSI" status ("locally developed PCR tests for MSI-H").

Labeling here
https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/125514s014lbl.pdf


Clinical study table 24, table 25, page 41.  In colorectal cancer, N=90, ORR rises from 36% to 46%.  But Duration of Responses rises from 1.6 months to 22 months.

Other cancers were studied - in total 59, of which 14 endometrial, 11 biliary, 9 gastric, etc.  Many cases were studied N of 1.  There were variable but meaningful increases in ORR but big increases in DOR.

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For the Keytruda discussion in a December 2017 article on precision medicine in Nat Rev Clin Onc, by Moscow, Fojo & Schilsky (NCI, Columbia, ASCO), see here and clipping below.

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The December 21, 2017 NEJM has an interesting letter from Yarchoan and colleagues at Johns Hopkins plotting three things together:  ORR, TMB, and Tumor Type in one graphic.