Hemab Therapeutics reports encouraging Phase 2 MAD results for sutacimig in Glanzmann thrombasthenia (GT) at ASH 2025, with plans to move into a pivotal Phase 3 study in 2026. Across bleed types, locations, and dose groups, the data show consistent, meaningful reductions in bleeding, supporting sutacimig as a potential first-in-class prophylactic option for GT. The weekly dosing cohort, in particular, suggests a strong impact on bleeding burden, including the most severe events that often require intensive care or transfusions.
Key takeaways from the Phase 2 program (N=34 in the MAD portion; efficacy analyzed in the broader population of 31) include a robust, dose-responsive reduction in annualized treated bleeding rate (ATBR) across major bleed sites such as nasal, gum/mouth, and gastrointestinal bleeds, with both traumatic and spontaneous bleeds showing benefit. Notably, the average ATBR fell by about 50% in the overall efficacy population, and the weekly-dose group achieved an roughly 87% reduction in ATBR (confidence interval approximately 80% to 92%).
The analysis also highlights a striking drop in high-intensity bleeding events—those necessitating interventions like recombinant factor VIIa, transfusions, plasma products, or invasive procedures—showing a 100% reduction in mean ATBR for these events during treatment. This suggests meaningful clinical value in preventing the kinds of bleeds that most threaten patient health and require urgent care.
Dose optimization findings indicate that weekly administration provides stable exposure throughout the dosing cycle, aligning with the observed clinical response. Overall, sutacimig was generally well tolerated. Most adverse events were mild to moderate and typical for GT patients; one treatment-related serious event (a grade 2 deep vein thrombosis) occurred at the highest dose tested (0.9 mg/kg). Anti-drug antibodies appeared in five participants, though titers resolved in one participant with continued dosing, and no safety concerns were linked to these antibodies.
Retention was strong, with 82% of participants choosing to enroll in the ongoing long-term extension study, underscoring perceived benefit and tolerability.
Presentation details:
- Title: Sutacimig, a Novel Bispecific Antibody for Prophylactic Treatment of Glanzmann Thrombasthenia: Phase 2 Analysis
- Session: OCCC - W304EFGH
- Presenter: Paul Saultier, MD, PhD, APHM Hospital de la Timone, France
- Data as of July 1, 2025
About Glanzmann Thrombasthenia (GT)
GT is a severe bleeding disorder characterized by frequent, sometimes life-threatening bleeds. The GT360 natural history study highlighted the heavy impact on patients’ lives: most experienced at least one bleed in the prior week, many required medical treatment, and a large portion faced mental health and social challenges. Prophylactic options remain unavailable, contributing to ongoing disease burden.
About Sutacimig (formerly HMB-001)
Sutacimig is a subcutaneously dosed bispecific antibody that acs as follows: one arm stabilizes endogenous Factor VIIa, while the other arm binds to activated platelets via TLT-1. This dual action concentrates Factor VIIa at the platelet surface to promote stable hemostasis and plug formation. Sutacimig is designed as a first-in-class prophylactic therapy for GT and could have broader applicability to other severe bleeding disorders. U.S. FDA Fast Track and Orphan Drug Designations support its development, with additional designation in the UK through the Innovative Licensing and Access Pathway.
About Hemab Therapeutics
Headquartered in Cambridge, MA, with a Copenhagen presence, Hemab is advancing a pipeline of prophylactic therapies for serious bleeding and thrombotic conditions. The company operates under a development strategy—Hemab 1-2-5—that aims to establish a durable portfolio addressing high unmet need diseases like GT, Factor VII deficiency, and von Willebrand disease. Learn more at hemab.com and follow updates on LinkedIn, Facebook, Instagram, and X.
Investor and media inquiries:
- Media: Deerfield, Peg Rusconi, media@deerfield.com
- Investors: Hemab Therapeutics, Mads Behrndt, investors@hemab.com
Source: Hemab Therapeutics
