Sirius Therapeutics Reports Promising Phase I Data for Factor XI siRNA Anticoagulant

At the 66th American Society of Hematology Annual Meeting in San Diego, Sirius Therapeutics presented encouraging preliminary findings from its Phase 1 clinical trial of SRSD107. This novel therapeutic, based on small interfering RNA (siRNA) technology, is under development for the prevention and treatment of thromboembolic conditions such as myocardial infarction, ischemic stroke, and venous thromboembolism. The promising data indicates SRSD107’s potential as a safer alternative to current anticoagulant therapies.

SRSD107 functions by inhibiting Factor XI (FXI), a protein involved in the coagulation cascade, which is crucial for thrombosis. The clinical trial, conducted as a single-site, randomized, double-blind, and placebo-controlled study, involved 40 healthy participants who received varying doses of SRSD107 through subcutaneous administration. This study aimed to assess the safety, tolerability, pharmacokinetics, and pharmacodynamics of the drug.

In this trial, participants were divided into five cohorts, each receiving different doses of SRSD107 or a placebo. Dr. Patrick Yue, the Chief Medical Officer at Sirius, reported that SRSD107 was both safe and well-tolerated by all subjects. The drug exhibited pharmacokinetic properties consistent with typical siRNA products. Importantly, the trial revealed significant pharmacodynamic effects, with notable reductions in FXI antigen and activity levels exceeding 90%. Additionally, there was an increase in activated partial thromboplastin time (aPTT) by over 100%, indicating enhanced anticoagulant effects without a significant increase in bleeding risks. These effects were sustained for more than 16 weeks post-dosing, highlighting the drug’s prolonged action.

Dr. Qunsheng Ji, the Chief Executive Officer of Sirius, emphasized the significance of these findings, noting that presenting them at the prestigious American Society of Hematology meeting highlights the company's dedication to developing innovative treatments for thromboembolic disorders. The trial’s success paves the way for advancing SRSD107 into Phase 2 studies.

Thromboembolic disorders, characterized by the formation of blood clots, are a leading cause of myocardial infarction, ischemic stroke, and venous thromboembolism. These conditions contribute significantly to global mortality rates, accounting for approximately one in four deaths worldwide. SRSD107 aims to address these disorders by specifically targeting and inhibiting FXI mRNA, thereby blocking the intrinsic coagulation pathway and promoting an anticoagulant effect. This innovative approach could potentially allow for once or twice-a-year dosing, offering a more convenient and effective alternative for patients.

Sirius Therapeutics, founded in 2021, is at the forefront of siRNA-based therapy development for chronic diseases. The company operates a discovery center in the United States and a translational medicine center in China. Its leading product candidates include SRSD107, designed for thromboembolic conditions, and SRSD101, aimed at treating dyslipidemia. With nearly $100 million in funding from prominent investors such as OrbiMed and Creacion Ventures, Sirius is committed to transforming siRNA technology into groundbreaking treatments that improve patient outcomes globally.