The PD-1 inhibitor dostarlimab made big headlines last year with its success as monotherapy for mismatch repair deficient (dMMR) rectal cancer. The single-arm phase 1 GARNET trial assessed the efficacy of this approach for all types of dMMR solid tumors recurrent or refractory to initial standard treatment. The primary endpoint of objective response rate was 44% (n=144) across 327 enrollees with mostly endometrial (43%) and colorectal (32%) tumors. Even more encouraging was that nearly three-quarters (n=104) of responders continued to respond for over a year with median duration of response not reached. | André, Jama Netw Open 2023
