CRISPR Therapeutics and Sirius Therapeutics Announce First Patient Dosed in Phase 2 Trial of SRSD107 for Thromboembolic Disorders in Europe

Core Insights - CRISPR Therapeutics and Sirius Therapeutics have initiated a Phase 2 clinical trial for SRSD107, a long-acting Factor XI siRNA aimed at preventing venous thromboembolism in patients undergoing total knee arthroplasty [1][2] Company Overview - CRISPR Therapeutics is focused on developing gene-based medicines for serious diseases and has a diverse portfolio that includes CRISPR/Cas9 gene editing therapies [8] - Sirius Therapeutics is a clinical-stage biotech company developing innovative siRNA therapies, with a pipeline targeting coagulation disorders and other chronic diseases [10][11] Clinical Trial Details - The Phase 2 trial is a randomized, multicenter, global study assessing the safety and efficacy of SRSD107 for VTE prevention in TKA patients [2] - SRSD107 aims to selectively inhibit FXI, a key factor in pathological thrombosis, while minimizing effects on normal hemostasis [3] Previous Trial Results - In Phase 1 trials, SRSD107 demonstrated strong pharmacodynamic effects, achieving over 93% reduction in FXI levels and more than twofold increase in activated partial thromboplastin time [3] Collaboration Insights - The strategic collaboration between CRISPR Therapeutics and Sirius Therapeutics was established in 2025 to co-develop siRNA therapies, sharing costs and profits equally [6][7] - CRISPR Therapeutics will lead commercialization efforts in the U.S., while Sirius will focus on Greater China [6] Market Potential - The addressable population for SRSD107 includes patients with various conditions such as atrial fibrillation, VTE, and chronic coronary artery disease, where existing therapies have limitations due to bleeding risks [3]