EMITT-1 interim data show that GRWD5769, an oral ERAP1 inhibitor, combined with cemiplimab produced durable responses across six recruited phase 1b expansion cohorts. The study evaluated patients with secondary resistance to anti–PD-1 therapy and MSS-CRC, with the company reporting no observed safety signals at interim follow-up. Across cohorts (n=81), ORR was reported in the 10%–33% range and durable clinical benefit (DCB, CR/PR/SD lasting at least six months) ranged from 26%–57%. Median PFS varied from 1.9 to 7.5 months, while immune-related adverse events were limited in frequency, with one grade 3+ event (immune hepatitis) attributed to treatment discontinuation. Translational work tied clinical benefit to increased TCR repertoire diversity and antigen-driven T-cell remodeling, consistent with GRWD5769’s goal of broadening antigen presentation and reducing the risk of exhausted T-cell states. Stage 2 expansions are ongoing to support a randomized phase 2 program.