Sirius Therapeutics and CRISPR Therapeutics Announce Strategic Collaboration to Advance Next-Generation siRNA Therapy SRSD107 for Thrombotic Disorders

May 20, 2025 — Sirius Therapeutics, a clinical-stage biotechnology company focused on developing innovative small interfering RNA (siRNA) therapies for the global market, and CRISPR Therapeutics (NASDAQ: CRSP), a biopharmaceutical company dedicated to developing transformative gene therapies for serious diseases, announced a strategic partnership to jointly advance the development and commercialization of siRNA therapies.Hankang Capital led the Series B financing of Sirius Therapeutics in 2023 and continued to support in subsequent rounds.

SRSD107 is a next-generation long-acting siRNA therapy designed to selectively inhibit coagulation factor XI (FXI). The FXI target plays a crucial role in pathological thrombosis but has minimal impact on normal hemostatic function. By targeting FXI, SRSD107 is expected to reduce the occurrence of thrombotic events while significantly lowering the risk of bleeding, demonstrating therapeutic advantages distinct from factor Xa (FXa) inhibitors. The potential indications for SRSD107 are broad and include atrial fibrillation, venous thromboembolism (VTE), cancer-associated thrombosis, end-stage renal disease patients undergoing hemodialysis, as well as individuals undergoing major orthopedic surgeries where bleeding risks limit current treatment options.

Currently, SRSD107 has completed two Phase 1 clinical trials, showing good safety and tolerability in single-dose administration. Relevant research findings were presented at the 2025 American College of Cardiology (ACC) Annual Scientific Session and the 2024 American Society of Hematology (ASH) Annual Meeting. The Phase 2 clinical trial of SRSD107 is being initiated to evaluate its safety and efficacy in preventing venous thromboembolism (VTE) in patients undergoing knee replacement surgery. This study will provide clinical scientific evidence for confirming its anticoagulant clinical benefits and dose selection for subsequent pivotal trials.

Both parties will jointly advance the development of SRSD107 through a 50:50 cost and profit-sharing model. According to the agreement, CRISPR Therapeutics will be responsible for the commercialization of the product in the United States, while Sirius Therapeutics will oversee the market in Greater China.

In addition, CRISPR Therapeutics has the right to nominate up to two siRNA targets and may choose to lead subsequent clinical development and commercialization. Sirius Therapeutics will be eligible to receive milestone payments tied to project progress, incentive payments subject to specific conditions, and tiered royalties based on sales revenue.

Thrombosis, the formation of blood clots within blood vessels that restrict blood flow, can occur in either arterial or venous circulation. It is the common pathological basis for most myocardial infarctions, ischemic strokes, and venous thromboembolism (VTE). Globally, one in four people die from diseases caused by thromboembolism.

SRSD107 Injection is a double-stranded small interfering nucleic acid (siRNA) drug independently developed by Sirius Therapeutics. By specifically targeting the liver-directed human coagulation factor XI (FXI) mRNA, it inhibits the protein expression of FXI, blocking the activation of the intrinsic coagulation pathway, thereby exerting an anticoagulant effect. Preclinical trial data show that a single subcutaneous injection of SRSD107 can reduce the concentration of FXI in peripheral blood by nearly 100%, with effects lasting up to half a year without any bleeding observed. With its potent, long-lasting efficacy and favorable safety profile, SRSD107 has the potential to become a First-in-Class and Best-in-Class next-generation safer anticoagulant.

Sirius Therapeutics is a clinical-stage biotechnology company dedicated to advancing human health and well-being. It is a leader in developing groundbreaking siRNA therapies aimed at revolutionizing the prevention and treatment of chronic diseases. Its current pipeline includes SRSD107 for thromboembolic disorders, SRSD216 for elevated lipoprotein(a), and SRSD101 for dyslipidemia, all of which have entered the clinical development phase.

Founded in 2021, incubated by an internationally excellent management team and globally renowned healthcare investment institutions. The company adopts an international strategic positioning, leveraging the talent and resource advantages in the field of small nucleic acid therapy from both China and the United States. It has established a layout with the United States as the source innovation discovery center and China as the global translational medicine center. Utilizing its core technology platform for small nucleic acid drug research and development, the company has developed multiple product pipelines with differentiated global competitive advantages, possessing first-in-class or best-in-class potential. The company has cumulatively raised nearly 150 million US dollars.

Since its establishment more than a decade ago, CRISPR Therapeutics has evolved from a research-based company dedicated to advancing gene-editing programs into an industry leader, celebrating the historic moment of the world's first approved CRISPR gene therapy. The company boasts a diversified portfolio of product candidates spanning a wide range of disease areas, including hemoglobinopathies, oncology, regenerative medicine, cardiovascular diseases, autoimmune diseases, and rare diseases. In 2018, CRISPR Therapeutics advanced the first CRISPR/Cas9 gene-editing therapy into clinical trials for the investigation of treatments for sickle cell disease and transfusion-dependent beta-thalassemia. Starting from the end of 2023, CASGEVY^®(exagamglogene autotemcel [exa-cel]) has been approved in multiple countries for the treatment of eligible patients with sickle cell disease or transfusion-dependent beta-thalassemia. The CRISPR technology, pioneered by Nobel laureates, has revolutionized biomedical research, representing a clinically validated and powerful approach with the potential to create an entirely new class of potentially transformative medicines. To accelerate and expand its efforts, CRISPR Therapeutics has established strategic partnerships with leading companies such as Vertex Pharmaceuticals. CRISPR Therapeutics AG is headquartered in Zug, Switzerland, with its wholly-owned subsidiary, CRISPR Therapeutics, Inc., located in the United States. Its research and development operations are based in Boston, Massachusetts, and San Francisco, California.

Hankang Capital is a venture capital fund focused on the pharmaceuticals and healthcare industry. With the mission of "empowering pharmaceutical innovation and safeguarding human health," the fund collaborates with top scientists and entrepreneurs to develop breakthrough drugs for major diseases. Rooted in China while looking globally, Hankang Capital has invested in multiple enterprises that have grown into industry leaders, such as Akeso Inc. (09926.HK), InnoCare Pharma (09969.HK, 688428.SH), Connaught Biologics (02162.HK), Abbisko Therapeutics (02256.HK), DualityBio Inc. (09606.HK), Chipscreen Biosciences (688321.SH), and Opthea (688293.SH).