CRISPR Therapeutics and Sirius Therapeutics Announce First Patient Dosed in Phase 2 Trial of SRSD107 for Thromboembolic Disorders in Europe
CRISPR Therapeutics (NASDAQ: CRSP) and Sirius Therapeutics have announced the dosing of the first patient in a Phase 2 clinical trial of SRSD107, their co-developed Factor XI (FXI) siRNA therapy for preventing venous thromboembolism in total knee arthroplasty patients.
SRSD107 demonstrated promising results in Phase 1 trials, showing over 93% reduction in FXI levels and a twofold increase in aPTT relative to baseline. The treatment's effects were sustained for up to six months post-dosing, suggesting potential for semi-annual administration.
The therapy aims to address limitations of current anticoagulants by reducing pathological thrombosis while minimizing bleeding risk. The addressable market includes patients with atrial fibrillation, VTE, cancer-associated thrombosis, and various cardiovascular conditions where bleeding risk currently limits treatment options.
CRISPR Therapeutics (NASDAQ: CRSP) e Sirius Therapeutics hanno annunciato l’avvio della somministrazione del primo paziente in uno studio clinico di Fase 2 di SRSD107, la loro terapia siRNA per FXI sviluppata congiuntamente, mirata a prevenire la tromboembolismo venoso nei pazienti sottoposti a artroplastica totale del ginocchio.
SRSD107 ha mostrato risultati promettenti nella fase 1, registrando una riduzione superiore al 93% dei livelli di FXI e un raddoppio dell’aPTT rispetto al basale. Gli effetti sono stati mantenuti fino a sei mesi dopo la somministrazione, suggerendo una potenziale somministrazione semestrale.
L’obiettivo della terapia è affrontare le limitazioni degli anticoagulanti attuali, riducendo la trombosi patologica e minimizzando il rischio di sanguinamento. Il mercato indirizzabile comprende pazienti con fibrillazione atriale, VTE, trombosi associata al cancro e diverse condizioni cardiovascolari in cui il rischio di sanguinamento limita attualmente le opzioni di trattamento.
CRISPR Therapeutics (NASDAQ: CRSP) y Sirius Therapeutics han anunciado el inicio de la administración al primer paciente en un ensayo clínico de Fase 2 de SRSD107, su terapia de siRNA para FXI desarrollada conjuntamente para prevenir la tromboembolismo venoso en pacientes sometidos a artroplastia total de rodilla.
SRSD107 mostró resultados prometedores en la fase 1, con una reducción de más del 93% de los niveles de FXI y un doble incremento en el tiempo de tromboplastina activada (aPTT) respecto al basal. Los efectos se mantuvieron hasta seis meses tras la dosificación, lo que sugiere una posible administración semestral.
La terapia busca abordar las limitaciones de los anticoagulantes actuales al reducir la trombosis patológica mientras minimiza el riesgo de sangrado. El mercado objetivo incluye pacientes con fibrilación auricular, VTE, trombosis asociada al cáncer y varias condiciones cardiovasculares donde el riesgo de sangrado actualmente limita las opciones de tratamiento.
CRISPR Therapeutics (NASDAQ: CRSP)와 Sirius Therapeutics는 SRSD107의 2상 임상시험에서 첫 환자 투여를 발표했습니다. 이는 무릎 전치환술 환자에서 정맥 혈전증 예방을 위한 FXI-siRNA 치료제입니다.
SRSD107은 1상에서 UX가 높은 성과를 보였으며 FXI 수치가 93% 이상 감소하고 기저선 대비 aPTT가 2배 증가하는 결과를 보여주었습니다. 투여 후 최대 6개월까지 효과가 지속되어 반년 간격 투여 가능성을 시사합니다.
이 치료제는 현재 항응고제의 한계를 줄이고 출혈 위험을 최소화하면서 병적 혈전증을 감소시키는 것을 목표로 합니다. 대상 시장은 심방세동, VTE, 암 관련 혈전증 및 출혈 위험이 여전히 치료 옵션을 제한하는 다양한 심혈관 질환 환자를 포함합니다.
CRISPR Therapeutics (NASDAQ: CRSP) et Sirius Therapeutics ont annoncé l’administration du premier patient dans un essai clinique de Phase 2 de SRSD107, leur thérapie siRNA ciblant FXI développée conjointement, destinée à prévenir l’embolie veineuse chez les patients ayant subi une arthroplastie totale du genou.
SRSD107 a montré des résultats prometteurs en Phase 1, avec une réduction de plus de 93 % des niveaux de FXI et un doublement de l’aPTT par rapport au baselined. Les effets ont perduré jusqu’à six mois après la dose, suggérant une administration semestrielle potentielle.
La thérapie vise à répondre aux limites des anticoagulants actuels en réduisant la thrombose pathologique tout en minimisant le risque de saignement. Le marché adressable comprend les patients atteints de fibrillation auriculaire, VTE, thrombose associée au cancer et diverses conditions cardiovasculaires où le risque de saignement limite actuellement les options de traitement.
CRISPR Therapeutics (NASDAQ: CRSP) und Sirius Therapeutics haben die Verabreichung des ersten Patienten in einer Phase-2-Studie von SRSD107 angekündigt, ihrer gemeinsam entwickelten FXI-siRNA-Therapie zur Vorbeugung von venösen Thromboembolien bei Patienten nach einer Totalendoprothese des Knies.
SRSD107 zeigte in der Phase 1 vielversprechende Ergebnisse, mit einer Reduktion der FXI-Werte um über 93% und einer Verdopplung der aPTT gegenüber der Basislinie. Die Wirkungen hielten bis zu sechs Monate nach der Verabreichung an, was auf eine potenzielle halbjährliche Gabe hindeutet.
Die Therapie zielt darauf ab, die Einschränkungen aktueller Antikoagulanzien zu adressieren, indem sie pathologische Thrombosen reduziert und gleichzeitig das Blutungsrisiko minimiert. Der adressierbare Markt umfasst Patienten mit Vorhofflimmern, VTE, krebsspezifischer Thrombose und verschiedene kardiovaskuläre Erkrankungen, bei denen das Blutungsrisiko derzeit Behandlungsmöglichkeiten einschränkt.
CRISPR Therapeutics (NASDAQ: CRSP) و Sirius Therapeutics قد أعلنا عن بدء علاج أول مريض في تجربة سريرية من المرحلة الثانية لـ SRSD107، علاج siRNA لـ FXI طورته الشركتان معًا لمنع الانصمام الوريدي عند مرضى تبديل مفصل الركبة الكامل.
أظهر SRSD107 نتائج واعدة في المرحلة 1، حيث سجل انخفاضًا يتجاوز 93% في مستويات FXI وزيادة مضاعفة في aPTT مقارنة بالخط الأساس. بقيت آثار العلاج حتى ستة أشهر بعد الإعطاء، مما يشير إلى احتمال إعطاء نصف سنوي.
يهدف العلاج إلى معالجة قيود مضادات التخثر الحالية من خلال تقليل التخثر المرضي مع تقليل مخاطر النزف. السوق القابل للوصول يشمل مرضى الرجفان الأذيني، والتخثر الوريدي العميق، والتخثر المرتبط بالسرطان، وحالات قلبية وعائية أخرى where مخاطر النزف تقيد خيارات العلاج حاليًا.
CRISPR Therapeutics (NASDAQ: CRSP) 与 Sirius Therapeutics 已宣布在 SRSD107 的一个 2 期临床试验中为首名患者给药，这是他们共同开发的 FXI 的 siRNA 疗法，旨在预防全膝置换术患者的静脉血栓栓塞。
SRSD107 在 1 期试验中显示出有希望的结果，FXI 水平下降>93%，aPTT 相比基线翻倍。治疗效果可持续至给药后六个月，表明有半年度给药的潜力。
该疗法旨在通过降低病理性血栓形成同时最小化出血风险，来解决当前抗凝药物的局限性。可覆盖的市场包括房颤、VTE、癌症相关血栓以及出血风险目前限制治疗选择的各种心血管疾病患者。
- None.
- Still in early clinical development phase with efficacy yet to be proven in Phase 2
- Complex competitive landscape in the anticoagulant market
Insights
CRISPR and Sirius begin Phase 2 trial of novel blood clot prevention therapy with differentiated efficacy and safety profile.
CRISPR Therapeutics and Sirius Therapeutics have reached a significant clinical milestone with their first patient dosed in a Phase 2 trial for SRSD107, a Factor XI (FXI) small interfering RNA therapy for preventing venous thromboembolism in patients undergoing total knee replacement surgery. This represents important progress in their cardiovascular disease pipeline.
The scientific approach here is particularly noteworthy. By selectively targeting Factor XI, SRSD107 aims to prevent pathological blood clots while minimizing bleeding complications that plague current anticoagulants. Phase 1 data showed impressive 93% reductions in FXI levels with effects lasting up to six months after a single dose. The extended duration suggests potential for twice-yearly dosing - a dramatic improvement over daily anticoagulant regimens currently required for high-risk patients.
The therapeutic profile presents multiple competitive advantages: long-lasting effects, subcutaneous administration, and a reversibility feature not seen in competing FXI inhibitors. This combination could position SRSD107 as best-in-class if Phase 2 results confirm the preliminary findings.
The addressable market is substantial, spanning multiple conditions where thrombosis prevention is critical but bleeding risk creates treatment challenges: atrial fibrillation, venous thromboembolism, cancer-associated thrombosis, coronary artery disease, peripheral vascular disease, hemodialysis patients, and orthopedic surgery patients. This breadth of potential applications significantly expands the commercial opportunity for both companies.
ZUG, Switzerland and BOSTON and SAN DIEGO and SHANGHAI, Sept. 22, 2025 (GLOBE NEWSWIRE) -- CRISPR Therapeutics (NASDAQ: CRSP), a biopharmaceutical company focused on creating transformative gene-based medicines for serious diseases, and 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 Phase 2 clinical trial of SRSD107, a next-generation, long-acting Factor XI (FXI) siRNA for the prevention of venous thromboembolism (VTE) in patients undergoing total knee arthroplasty (TKA). SRSD107 is being co-developed by CRISPR Therapeutics and Sirius Therapeutics as part of a strategic collaboration to advance innovative treatments for cardiovascular and clotting-related diseases.
“We are pleased to announce that our Phase 2 clinical trial is now underway, and the first patient has been dosed,” said Naimish Patel, M.D., Chief Medical Officer of CRISPR Therapeutics. “Until now, existing anticoagulant options have been limited by bleeding risk, frequent dosing, and complex management challenges for patients with high thrombotic risk. SRSD107 offers the potential to reduce pathological thrombosis while minimizing bleeding risk, with sustained but reversible pharmacodynamic effects and the possibility of infrequent dosing. We look forward to exploring how this differentiated approach could meaningfully improve outcomes for patients in need.”
“We are very excited to announce that the first patient has been dosed in our Phase 2 trial of SRSD107, marking a significant milestone for this program,” said Patrick Yue, M.D., Chief Medical Officer of Sirius Therapeutics. “This study will evaluate clinical efficacy as proof of concept for Factor XI inhibition using our siRNA approach, building on the positive results from our Phase 1 trials, and we look forward to the progress of this trial.”
The ongoing Phase 2 clinical trial is a randomized, multicenter, global study evaluating the safety and efficacy of SRSD107 for the prevention of VTE in patients undergoing TKA. The trial will assess the anticoagulant effects and pharmacological profile of SRSD107 and help inform dose selection for future pivotal studies, with the goal of confirming its potential as a differentiated approach for reducing thrombotic risk in patients.
SRSD107 is designed to selectively inhibit FXI, a key driver of pathological thrombosis, with minimal impact on normal hemostasis. In prior Phase 1 clinical trials conducted in Australia and China, single doses of SRSD107 were well tolerated and demonstrated strong, sustained pharmacodynamic effects, including reductions of over
About Thromboembolic Disorders
Thrombosis, or blood clot formation, is the common underlying mechanism of most cases of myocardial infarction, ischemic stroke, and venous thromboembolism. Published data in The Lancet1 estimate that thromboembolic disorders are estimated to account for approximately one in four deaths worldwide.
About SRSD107
SRSD107 is a novel double-stranded small interfering ribonucleic acid (siRNA), that is designed to target the human coagulation factor XI (FXI) mRNA and inhibit FXI protein expression. By modulating the intrinsic coagulation pathway, SRSD107 has the potential to provide anticoagulant and antithrombotic effects.
About the CRISPR Therapeutics and Sirius Therapeutics Collaboration
CRISPR Therapeutics and Sirius Therapeutics entered into a strategic collaboration in 2025 to develop and commercialize novel small interfering RNA (siRNA) therapies for thromboembolic disorders and other serious diseases. The lead program, SRSD107, is a long-acting siRNA targeting Factor XI (FXI) with the potential to offer best-in-class efficacy and safety. Under the agreement, the companies will co-develop SRSD107 and share costs and profits equally. CRISPR Therapeutics will lead commercialization in the U.S., while Sirius will lead in Greater China. The collaboration also provides CRISPR Therapeutics with the option to license up to two additional siRNA programs. This partnership expands CRISPR Therapeutics’ therapeutic portfolio into RNA-based medicines, complementing its ongoing efforts in gene editing and broadening its impact across serious and chronic diseases. For Sirius, the collaboration marks a major milestone in its mission to deliver innovative RNA-based therapies globally, leveraging deep expertise in siRNA design and delivery.
About CRISPR Therapeutics
Since its inception over a decade ago, CRISPR Therapeutics has evolved from a research-stage company advancing gene editing programs into a leader that celebrated the historic approval of the first-ever CRISPR-based therapy. The Company has a diverse portfolio of product candidates across a broad range of disease areas including hemoglobinopathies, oncology, regenerative medicine, cardiovascular, autoimmune, and rare diseases. In 2018, CRISPR Therapeutics advanced the first-ever CRISPR/Cas9 gene-edited therapy into the clinic to investigate the treatment of sickle cell disease and transfusion-dependent beta thalassemia. Beginning in late 2023, CASGEVY® (exagamglogene autotemcel [exa-cel]) was approved in several countries to treat eligible patients with either of these conditions. The Nobel Prize-winning CRISPR technology has revolutionized biomedical research and represents a powerful, clinically validated approach with the potential to create a new class of potentially transformative medicines. To accelerate its efforts, CRISPR Therapeutics has formed strategic partnerships with leading companies, including Vertex Pharmaceuticals. CRISPR Therapeutics AG is headquartered in Zug, Switzerland, with its wholly-owned U.S. subsidiary, CRISPR Therapeutics, Inc., and R&D operations based in Boston, Massachusetts and San Francisco, California. To learn more, visit www.crisprtx.com.
CRISPR THERAPEUTICS® standard character mark and design logo are trademarks and registered trademarks of CRISPR Therapeutics AG. CASGEVY® and the CASGEVY logo are registered trademarks of Vertex Pharmaceuticals Incorporated. All other trademarks and registered trademarks are the property of their respective owners.
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
CRISPR Therapeutics Forward-Looking Statement
Statements contained in this press release regarding matters that are not historical facts are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Such statements include, but are not limited to, statements made by Drs. Patel and Yue in this press release, as well as regarding any or all of the following: (i) CRISPR Therapeutics’ preclinical studies, clinical trials and pipeline products and programs, including, without limitation, expectations regarding data, safety and efficacy generally; (ii) data included in this press release, as well as the ability to use data from ongoing and planned clinical trials for the design and initiation of further clinical trials; (iii) the status and clinical progress of the SRSD107 clinical program and development timelines for such program; (iv) CRISPR Therapeutics’ strategy and goals; (v) the future activities of the parties pursuant to the collaboration and the expected benefits of CRISPR Therapeutics’ collaboration with Sirius Therapeutics; and (vi) the therapeutic value, development, and commercial potential of gene editing and delivery technologies and therapies, including CRISPR/Cas9. Risks that contribute to the uncertain nature of the forward-looking statements include, without limitation, the risks and uncertainties discussed under the heading “Risk Factors” in its most recent annual report on Form 10-K and in any other subsequent filings made by CRISPR Therapeutics with the U.S. Securities and Exchange Commission. Existing and prospective investors are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date they are made. CRISPR Therapeutics disclaims any obligation or undertaking to update or revise any forward-looking statements contained in this press release, other than to the extent required by law. This press release discusses investigational therapies and is not intended to convey conclusions about efficacy or safety as to those investigational therapies or uses of such investigational therapies. There is no guarantee that any investigational therapy will successfully complete clinical development or gain approval from applicable regulatory authorities.
Sirius Therapeutics Forward Looking Statement
This press release may contain certain “forward-looking statements” which are not historical facts, but instead are predictions about future events based on Sirius Therapeutic’s current beliefs, assumptions and expectations, commonly identified by words such as "would", "may", "expects", "believes", "plans", "intends", "projects" and other terms with similar meaning. Although we believe that our predictions are reasonable, future events are inherently uncertain, and our actual future results or performance may be materially different from what we expect. Accordingly, you are strongly cautioned that reliance on any forward-looking statements is subject to significant known and unknown risks and uncertainties. All forward-looking statements contained herein are qualified by reference to the cautionary statements set forth in this section. All information provided in this press release is as of the date of this press release and are based on assumptions that we believe to be reasonable as of this date, and we do not undertake any obligation to update any forward-looking statement, except as required under applicable law.
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1 Lozano R, Naghavi M, Foreman K, et al. Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet. 2012;380, 2095-1128.
FAQ
What is SRSD107 and what did CRISPR Therapeutics announce about it?
What were the results of SRSD107's Phase 1 clinical trials?
How does SRSD107 differ from existing anticoagulant treatments?
What conditions could SRSD107 potentially treat?
What is the partnership between CRISPR Therapeutics and Sirius Therapeutics for SRSD107?
