Scholar Rock presents new data from Phase 1 DRAGON trial

Scholar Rock announced new data from its Phase 1 DRAGON proof-of-concept trial of SRK-181, a selective inhibitor of latent TGFbeta1 activation being developed with the aim of overcoming resistance to checkpoint inhibitor therapy in patients with advanced cancer. These data will be presented in two poster presentations during the Society for Immunotherapy of Cancer’s (SITC) 38th Annual Meeting & Pre-Conference being held November 1 – 5th in San Diego. The first poster focuses on the safety, efficacy, and preliminary biomarker data in patients with anti-PD-1 resistant clear cell renal cell carcinoma (ccRCC) in Part A2 (dose escalation) and Part B (dose expansion) of the Phase 1 DRAGON trial. The ccRCC cohort was the focus for that poster, as it was the fastest cohort to achieve enrollment goals. The second poster focuses on preliminary biomarker data from part B of the trial in patients with multiple tumor types. Data presented continues to support proof of concept for SRK-181 in 28 heavily pretreated patients with ccRCC resistant to anti-PD-1. SRK-181 was generally well tolerated and showed promising anti-tumor activity in this patient population. Of 28 evaluable patients in the ccRCC cohort, six patients treated with SRK-181 in combination with pembrolizumab had confirmed partial responses (PRs) and achieved a best tumor reduction of 33% to 93%, with an objective response rate (ORR) of 21.4%. In the biomarker analysis for ccRCC, levels of circulating granulocytic myeloid-derived suppressor cells (gMDSC) correlated with clinical activity in ccRCC patients treated with SRK-181 in combination with pembrolizumab. The data cutoff for all analyses was August 29, 2023.