Sutacimig Phase 2 interim results demonstrate >50% reduction in treated bleeding event and prophylactic treatment potential in Glanzmann thrombasthenia
HMB-002 clinical proof-of-mechanism data in Von Willebrand disease support its potential as a first-in-class prophylactic therapy by elevating VWF levels and extending half-life
Natural history insights illuminate true patient burden and prophylactic opportunity to inform transformative, preventative solutions for underserved bleeding disorders
Hemab Therapeutics, a clinical-stage biotechnology company developing novel prophylactic therapeutics for serious, underserved bleeding and thrombotic disorders, today announced clinical and preclinical results at the International Society on Thrombosis and Haemostasis (ISTH) 2025 Congress in Washington, DC. The company’s 11 abstracts present breakthrough data for sutacimig (formerly HMB-001) and HMB-002, its lead therapeutic candidates, along with crucial insights from natural history studies.
“The data presented at ISTH underscore the potential for Hemab’s impact in addressing the severe unmet needs of people with bleeding disorders,” said Kate Madigan, Chief Medical Officer at Hemab. “Our sutacimig and HMB-002 data reveal important progress towards transformative, preventative solutions for these devastating diseases. We’re demonstrating the possibilities to meaningfully reduce bleeding and elevate care for people living with Glanzmann thrombasthenia and Von Willebrand disease.”
Highlights of Clinical Presentations
Sutacimig shows promising safety and efficacy in Glanzmann thrombasthenia (GT). The Phase 2 study is fully enrolled (N=34 in Part B), and data show a clinically meaningful reduction in treated bleeding events.
- Clinically meaningful bleeding reduction: Sutacimig treatment in the efficacy population (n=33) demonstrated a >50% reduction in median Annualized Treated Bleeding Rate (ATBR), with the median ATBR decreasing from 21.2 to 4.61. Select patient reports indicate a reduced severity of bleeds and decreased IV rFVIIa use.
- Safety profile: Sutacimig demonstrated a favorable safety profile, with most adverse events (AEs) being mild to moderate in severity, and no reported thromboses or discontinuations due to AEs in ongoing dose levels of 0.3 and 0.6 mg/kg.
- PK/PD insights: At ongoing dose levels of 0.3 and 0.6 mg/kg, Factor VIIa (FVIIa) accumulation reached 2-4 fold above baseline. Exploratory thrombin generation assays suggested hemostatic activity, with observed improvements comparable to those seen with clinically relevant concentrations of rFVIIa.
Late Breaking Abstract presentation of HMB-002 demonstrates positive proof of mechanism in Von Willebrand disease (VWD), with the first-in-human VELORA Pioneer study in Type 1 VWD patients.
- Favorable safety profile: No treatment-emergent AEs, injection-site reactions, hypersensitivity, or serious AEs were reported in the VELORA Pioneer Cohort A1.
- Encouraging endogenous Von Willebrand Factor (VWF) and FVIII accumulation: The VELORA Pioneer study demonstrated that the initial single 20mg subcutaneous dose of HMB-002 induced consistent and sustained increases in VWF and Factor VIII FVIII levels. Within 14 days, mean VWF rose >1.5-fold from baseline.
- Normalized APTT and improved thrombin generation: Parallel to the increases in VWF, levels of Factor VIII were corrected, resulting in normalization in APTT and thrombin generation.
Preclinical data highlights
- Sutacimig enhances rFVIIa efficacy in in vitro studies, enabling potentially lower doses for breakthrough bleeds. Studies also show sutacimig preserves the function of stored platelet concentrates (PCs), supporting its mechanism that could reduce both rFVIIa doses and PC volumes needed for bleeding control.
- Nonclinical safety evaluations of HMB-002 in cynomolgus monkeys and in vitro/ex vivo assays showed no adverse effects, immunotoxicity (including complement and platelet activation or cytokine release), or off-target binding, indicating a favorable safety profile.
- Extended half-life and infrequent dosing: Pharmacokinetic modeling estimated a long HMB-002 half-life, supporting infrequent subcutaneous dosing. In studies with cynomolgus monkeys, HMB-002 also extended exogenously administered recombinant VWF’s half-life, leading to the time-dependent accumulation of endogenous VWF and FVIII, and resulted in an approximately 3-fold prolongation of recombinant VWF in circulation.
Natural history highlights
- GT: Recent findings complementing previous natural history data confirm the severe, often underestimated disease burden of GT. The ATHN Transcends GT study quantifies this with a mean Annualized Bleeding Rate (ABR) of 72.0, with most bleeds requiring treatment (ATBR of 51.9) and 56% of participants experiencing a severe disease burden. A separate retrospective analysis of US-based real-world patient records reveals how this frequent blood loss initiates a self-perpetuating cycle of blood loss and iron deficiency anemia that worsens complications for all patients. This cycle creates a disproportionate unmet need for women, who report high rates of hemorrhage (75%) and anemia (23%), often triggered by heavy menstrual bleeding. Men are also heavily burdened, with significantly higher rates of gastrointestinal bleeding (36%) and hematomas (30%). A systematic care gap compounds the clinical crisis: management is mainly limited to on-demand treatments administered post-bleed, and a large proportion of patients are cared for outside of specialized hematology centers, contributing to ongoing underdiagnosis and underestimation of disease prevalence. This highlights a critical need for improved access to expert care and effective prophylactic therapies for all individuals with GT.
- VWD: New lived-experience data from the VWD360 study reveals a much higher than previously reported unmet need in VWD, highlighting a significant socioeconomic and psychological burden, especially the disproportionate impact on women suffering from heavy menstrual bleeding. The study found that participants averaged 1.33 bleeds weekly, with 71% missing work and high rates of low mood (73%). Crucially, data from a VWD360 substudy and VELORA Discover challenge historical assumptions, showing Type 1 VWD bleeding rates are comparable to, or even higher than, other subtypes, revealing a major care gap for this neglected patient population.
Benny Sorensen, MD, PhD, CEO of Hemab, stated, “Our multiple ISTH presentations underscore Hemab’s commitment to leveraging the biotechnological revolution and deep hemostasis expertise to develop innovative prophylactic therapies for patients with bleeding disorders. Our dedication to always listening to the people living with these diseases has generated extensive natural history data revealing substantially greater unmet medical need than previously recognized, driving our continued clinical advancement.”
