Sirius Therapeutics Announces First Patient Dosed in Phase 2 Trial of SRSD107 for Chronic Coronary and/or Peripheral Arterial Disease

SAN DIEGO and SHANGHAI March 17，2026-  Sirius Therapeutics, a clinical stage biotech company developing innovative small interfering RNA (siRNA) therapies for global markets, today announced that the first patient has been dosed in a second Phase 2 clinical trial of SRSD107, a next-generation, long-acting Factor XI (FXI) siRNA for subjects with chronic coronary and/or peripheral artery diseases. SRSD107 is being co-developed by Sirius Therapeutics and CRISPR Therapeutics as part of a strategic collaboration to advance innovative treatments for cardiovascular and clotting-related diseases.

“We are pleased to announce that the first patient has been dosed in our second Phase 2 trial of SRSD107,” said Dr. Qunsheng Ji, Chief Executive Officer of Sirius Therapeutics. “Recent clinical successes across the Factor XI class continue to support the therapeutic potential of this approach. We believe SRSD107 represents a novel, long-acting anti-coagulant designed to provide consistent target inhibition, supporting its development as a potential chronic therapy. This study will evaluate the safety, tolerability, and pharmacokinetic, and pharmacodynamic profile of SRSD107 following multiple doses, building on data being generated from our ongoing Phase 2 study.”

“Dosing the first patient in this additional Phase 2 clinical trial represents an important step forward for the SRSD107 program,” said Dr. Patrick Yue, Chief Medical Officer of Sirius Therapeutics. “Despite advances in standard-of-care therapies, patients with chronic coronary artery disease and/or peripheral arterial disease continue to experience substantial residual risk. Building on the clinical experience with SRSD107 to date, the study expands our Phase 2 development program into a broader patient population and is intended to further evaluate a long-acting profile with the potential to support durable target inhibition and infrequent dosing, including the possibility of dosing as infrequently as every six months."

SRSD107 is being evaluated in a randomized, multicenter Phase 2 clinical trial designed to assess its safety, tolerability, pharmacokinetic and pharmacodynamic profile in patients with chronic coronary and/or peripheral artery diseases. The trial will be conducted across sites in China, and will assess the anticoagulant effects and safety profile of multiple doses of SRSD107 administered in combination with aspirin to inform dose selection for future pivotal trials.

In addition to this study, SRSD107 is also being evaluated in an ongoing Phase 2 clinical trial for the prevention of venous thromboembolism (VTE) following total knee arthroplasty (TKA), further contributing to the overall clinical experience with the program across both arterial and venous settings.

Across its clinical development program, SRSD107 is being advanced for a range of thromboembolic and clotting-related indications, including arterial fibrillation (AF), VTE, ischemic stroke, cancer-associated thrombosis (CAT), chronic kidney disease (CKD), peripheral vascular disease (PVD), chronic coronary artery disease (CAD), and settings where bleeding risk limits existing therapies.

About SRSD107

SRSD107 is a novel double-stranded siRNA, designed to target the human coagulation FXI messenger RNA and inhibit FXI protein expression. Through modulation of the intrinsic coagulation pathway, SRSD107 is intended to provide anticoagulant and antithrombotic effects. Supported by clinical experience to date, SRSD107 is currently being evaluated in Phase 2 clinical trials across both venous and arterial thrombotic indications. SRSD107 is being developed as a long-acting FXI inhibitor with the potential to support infrequent, including semi-annual, subcutaneous administration.

About Chronic Artery Disease (CAD) and Peripheral Artery Disease (PAD)

Coronary Artery Disease (CAD) and Peripheral Artery Disease (PAD) are common and serious manifestations of atherosclerotic cardiovascular disease caused by the buildup of plaque in the arteries that restricts blood flow to the heart and peripheral circulation, respectively. These conditions share common risk factors and frequently coexist, significantly increasing the risk of myocardial infarction, stroke and limb-related complications, including amputation. While antiplatelet therapies such as aspirin remain foundational to treatment, there is growing recognition of the role of anticoagulation in selected high-risk patients. Targeting complementary pathways involved in thrombosis may provide additional protection against acute thrombotic events in patients with advanced or diffuse atherosclerotic disease.

About the Sirius Therapeutics and CRISPR Therapeutics Collaboration

Sirius Therapeutics and CRISPR Therapeutics entered into a strategic collaboration in 2025 to develop and commercialize novel siRNA therapies for thromboembolic disorders and other serious diseases. The lead program, SRSD107, is a long-acting siRNA targeting FXI. Under the agreement, the companies will co-develop SRSD107 and share costs and profits equally. Sirius Therapeutics will lead commercialization in Greater China, while CRISPR will lead in the U.S. The collaboration also provides CRISPR Therapeutics with the option to license up to two additional siRNA programs.

About Sirius Therapeutics

Sirius is a global, clinical-stage biotech company developing innovative siRNA therapies focusing on the treatment of chronic diseases. The Company's pipeline is centered around three key franchises with mega blockbuster potential: coagulation disorders, cardiometabolic diseases, and obesity. Sirius’ most advanced investigational programs include SRSD107, a FXI inhibitor targeting the anticoagulation market, SRSD216, an inhibitor of Lp(a) synthesis intended to address atherosclerotic cardiovascular disease, and SRSD384, an INHBE inhibitor for managing obesity.

Founded in 2021 by a world-class leadership team and investors, Sirius has established an innovation center in the United States and a translational medicine center in China. Sirius has raised nearly US$150 million in funding to date from OrbiMed, Creacion Ventures, Hankang Capital, Delos Capital, and BioTrack Capital.

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