Publication Number: 4472

 

Abstract Title : Real-world use of prophylaxis in people with non-severe hemophilia in the United States: Insights from the athn transcends Study - hemophilia natural history arm

 

Category: 900s - Health Services, Quality Improvement, and Outcomes Research

 

Review Category: 905. Outcomes Research: Non-Malignant Conditions Excluding Hemoglobinopathies

 

Authors

 

Fernando Corrales-Medina¹, Nana Afari-Dwamena², Amanda Blair³, Shannon Carpenter⁴, Clay Cohen⁵, Maissaa Janbain⁶, Janice Staber⁷, Jonathan Schwartz², Michael Recht^{8, 9}, Tammuella Chrisentery-Singleton^{2, 10}

 

¹ University of Miami-Hemophilia and Thrombosis Treatment Center, University of Miami-Miller School of Medicine, Division of Pediatric Hematology-Oncology, Miami, FL, United States, ² American Thrombosis and Hemostasis Network, Hickory, NC, United States, ³ Wake Forest University School of Medicine, Winston-Salem, NC, United States, ⁴ Kansas City Regional Hemophilia Center, The Children’s Mercy Hospital, Kansas City, MO, United States, ⁵ Texas Children's Cancer & Hematology Center, Baylor College of Medicine, Houston, TX, United States, ⁶ Louisiana Comprehensive Hemophilia Center, Tulane University Medical Center, New Orleans, LA, United States, ⁷ Iowa Hemophilia and Thrombosis Center, University of Iowa, Stead Family Department of Pediatric, Iowa City, IA, United States, ⁸ Yale Center for Bleeding and Clotting Disorders, Yale School of Medicine, New Haven, CT, United States, ⁹ National Bleeding Disorders Foundation, New York, NY, United States, ¹⁰ Ochsner Clinic Foundation, New Orleans, LA, United States

 

Abstract Body

 

Introduction: People with mild to moderate hemophilia are frequently underrepresented in clinical trials and registries, leading to gaps in evidence-based guidance. While early prophylaxis is standard in severe hemophilia, treatment approaches for non-severe disease remain inconsistent. This is often driven by the misconception that prophylaxis is appropriate only for individuals with residual factor ≤2%, despite increasing evidence of recurrent bleeds in non-severe cases. Heterogeneous bleeding phenotypes, evolving patient preferences, and provider uncertainty further contribute to this variation. Real-world data describing the use, selection, and safety of prophylaxis are essential to improving care for this population.

 

Methods: ATHN Transcends (NCT04398628) is a prospective, longitudinal, cohort study conducted at over 60 ATHN-affiliated sites across the United States. The Hemophilia Natural History Arm captures safety and effectiveness of hemophilia therapies including clinical and participant-reported outcomes. This analysis includes demographic and baseline clinical data for participants with mild (residual levels 6- <40%) or moderate (residual levels 1-5%) Hemophilia A (HA) or Hemophilia B (HB) enrolled participants from March 2021 to April 2025.

 

Results: A total of 158 participants were included: 110 with HA and 48 with HB. Participants with HA, 50 had moderate disease (mean FVIII 3.1% (1.4), median 3.0%) and 60 had mild disease (mean FVIII 18.1% (11.5), median 14.0%). Participants with HB, 26 had moderate disease (mean FIX 2.4% (1.0), median 2.0%) and 22 had mild disease (mean FIX 7.6% (10.4), median 15.5%). The mean age at enrollment was 16.4 years (min=0, max=78) for moderate HA and 29.4 years (2, 86) for mild HA. For HB, the mean age was 28.6 years (0, 71) for moderate and 18.7 years (2, 55) for mild disease. Females accounted for 13 (21.7%) of mild HA and 6 (27.3%) of mild HB participants; no females with moderate disease were enrolled. A target joint was reported in 6 (12%) of moderate HA, 4 (15.4%) of moderate HB, and 5 (8.3%) of mild HA participants. The mean age at first bleed was earlier in moderate compared to mild participants: 2.1 years (3.9) vs. 6.4 years (9.4) in HA, and 3.3 years (5.0) vs. 7.4 years (8.5) in HB. For HA participants, the head was the most reported site of first bleeding in both moderate and mild cases. In contrast, the most frequent site of first bleed for HB participants was the mouth. At enrollment, 58% of moderate HA and 37% of moderate HB participants reported use of continuous prophylaxis. In mild participants, 21.8% of HA and 15.8% of HB were also receiving prophylaxis. Short-term/intermittent prophylaxis was reported in 2% and 4.2% of moderate HA and HB, and in 7.3% and 10.5% of mild HA and HB, respectively. Females with mild HA, 2 (15%) reported continuous prophylaxis use. Among HA participants, emicizumab was the most used prophylactic agent (82.8% in moderate, 50.0% in mild), followed by standard half-life (SHL) recombinant FVIII concentrates in moderate HA (6.9%) and ultra-extended half-life (UEHL) FVIII concentrates for mild HA (21.4%). Most emicizumab users reported SHL concentrates as their as-needed therapy (41.9% in moderate, 58.3% in mild HA). The 2 females with mild HA on prophylaxis, one reported use of SHL and the other UEHL recombinant FVIII concentrates. In HB, extended half-life (EHL) recombinant factor IX concentrates were the most used prophylactic agents (77.8% in moderate, 60.0% in mild).

 

Conclusions: In this analysis, we demonstrate that over one third of ATHN Transcends participants with non-severe hemophilia were already receiving continuous prophylaxis, including a significant subset with mild disease. Prior publications reported prophylaxis use in fewer than one-third of moderate and under 30% of mild cases*. This shift reflects growing recognition that bleeding risk may not correlate with factor levels and supports a phenotype-driven approach to care. Our findings also highlight the role of emicizumab in HA, while HB patients still rely on FIX concentrates for prophylaxis. Ongoing follow-up will determine whether treatment patterns and adoption of newer hemostatic agents continue to evolve. These findings underscore the need to revisit prophylaxis guidelines and reinforce the importance of real-world data in shaping evidence-based, personalized care in non-severe hemophilia. *Iorio A, et al. Haemophilia. 2023 Jan;29(1):33-44.

 

Keywords: Research, Hemophilia, Adult, Clinical Research, Study Population, Bleeding and Clotting, Human, Real-World Evidence, Diseases, Young Adult, Pediatric

 

Disclosure : Fernando Corrales-Medina: Genentech, Consultancy (Includes expert testimony): Yes, Patents & Royalties: No, Ended employment in the past 24 months: No, Research Funding: No, Divested equity in a private or publicly-traded company in the past 24 months: No, Current equity holder in publicly-traded company: No, Current Employment: No, Current holder of stock options in a privately-held company: No, Current equity holder in private company: No, Honoraria: No, Novo Nordisk, Consultancy (Includes expert testimony): Yes, Patents & Royalties: No, Ended employment in the past 24 months: No, Research Funding: No, Divested equity in a private or publicly-traded company in the past 24 months: No, Current equity holder in publicly-traded company: No, Current Employment: No, Current holder of stock options in a privately-held company: No, Current equity holder in private company: No, Honoraria: No, Octapharma, Consultancy (Includes expert testimony): Yes, Patents & Royalties: No, Ended employment in the past 24 months: No, Research Funding: Yes, Divested equity in a private or publicly-traded company in the past 24 months: No, Current equity holder in publicly-traded company: No, Current Employment: No, Current holder of stock options in a privately-held company: No, Current equity holder in private company: No, Honoraria: No, Bayer, Consultancy (Includes expert testimony): Yes, Patents & Royalties: No, Ended employment in the past 24 months: No, Research Funding: No, Divested equity in a private or publicly-traded company in the past 24 months: No, Current equity holder in publicly-traded company: No, Current Employment: No, Current holder of stock options in a privately-held company: No, Current equity holder in private company: No, Honoraria: No, Takeda, Consultancy (Includes expert testimony): Yes, Patents & Royalties: No, Ended employment in the past 24 months: No, Research Funding: No, Divested equity in a private or publicly-traded company in the past 24 months: No, Current equity holder in publicly-traded company: No, Current Employment: No, Current holder of stock options in a privately-held company: No, Current equity holder in private company: No, Honoraria: No, Sanofi, Consultancy (Includes expert testimony): Yes, Patents & Royalties: No, Ended employment in the past 24 months: No, Research Funding: No, Divested equity in a private or publicly-traded company in the past 24 months: No, Current equity holder in publicly-traded company: No, Current Employment: No, Current holder of stock options in a privately-held company: No, Current equity holder in private company: No, Honoraria: No, Nana Afari-Dwamena: None declared, Amanda Blair: Bayer, Sanofi, and HEMABiologics, Consultancy (Includes expert testimony): Yes, Patents & Royalties: No, Ended employment in the past 24 months: No, Research Funding: No, Divested equity in a private or publicly-traded company in the past 24 months: No, Current equity holder in publicly-traded company: No, Current Employment: No, Current holder of stock options in a privately-held company: No, Current equity holder in private company: No, Honoraria: No, Shannon Carpenter: Genentech, Inc. Novo Nordisk, Consultancy (Includes expert testimony): No, Patents & Royalties: No, Ended employment in the past 24 months: No, Research Funding: No, Divested equity in a private or publicly-traded company in the past 24 months: No, Current equity holder in publicly-traded company: No, Current Employment: No, Current holder of stock options in a privately-held company: No, Current equity holder in private company: No, Honoraria: Yes, Clay Cohen: None declared, Maissaa Janbain: Octapharma, CSL Behring, Takeda, and Sanofi, Consultancy (Includes expert testimony): Yes, Patents & Royalties: No, Ended employment in the past 24 months: No, Research Funding: No, Divested equity in a private or publicly-traded company in the past 24 months: No, Current equity holder in publicly-traded company: No, Current Employment: No, Current holder of stock options in a privately-held company: No, Current equity holder in private company: No, Honoraria: No, Takeda and Sanofi, Consultancy (Includes expert testimony): No, Patents & Royalties: Yes, Ended employment in the past 24 months: No, Research Funding: No, Divested equity in a private or publicly-traded company in the past 24 months: No, Current equity holder in publicly-traded company: No, Current Employment: No, Current holder of stock options in a privately-held company: No, Current equity holder in private company: No, Honoraria: Yes, Janice Staber: Bayer, BioMarin, Genentech, Inc., Sanofi, Consultancy (Includes expert testimony): Yes, Patents & Royalties: No, Ended employment in the past 24 months: No, Research Funding: No, Divested equity in a private or publicly-traded company in the past 24 months: No, Current equity holder in publicly-traded company: No, Current Employment: No, Current holder of stock options in a privately-held company: No, Current equity holder in private company: No, Honoraria: No, Jonathan Schwartz: None declared, Michael Recht: Partner in Bleeding Disorders, Consultancy (Includes expert testimony): No, Patents & Royalties: No, Ended employment in the past 24 months: No, Research Funding: No, Divested equity in a private or publicly-traded company in the past 24 months: No, Current equity holder in publicly-traded company: No, Current Employment: No, Current holder of stock options in a privately-held company: No, Current equity holder in private company: No, Honoraria: No, Tammuella Chrisentery-Singleton: Make-a-Wish and American Heart Association, New Orleans (Leader), Consultancy (Includes expert testimony): No, Patents & Royalties: No, Ended employment in the past 24 months: No, Research Funding: No, Divested equity in a private or publicly-traded company in the past 24 months: No, Current equity holder in publicly-traded company: No, Current Employment: No, Current holder of stock options in a privately-held company: No, Current equity holder in private company: No, Honoraria: No, GBT/Pfizer Advisory Board, Consultancy (Includes expert testimony): Yes, Patents & Royalties: No, Ended employment in the past 24 months: No, Research Funding: No, Divested equity in a private or publicly-traded company in the past 24 months: No, Current equity holder in publicly-traded company: No, Current Employment: No, Current holder of stock options in a privately-held company: No, Current equity holder in private company: No, Honoraria: No, Octapharma, HEMA Biologics, Genentech, BioMarin, Novo Nordisk, CSL Behring, Takeda, Grifols, and Pfizer, Consultancy (Includes expert testimony): No, Patents & Royalties: No, Ended employment in the past 24 months: No, Research Funding: No, Divested equity in a private or publicly-traded company in the past 24 months: No, Current equity holder in publicly-traded company: No, Current Employment: No, Current holder of stock options in a privately-held company: No, Current equity holder in private company: No, Honoraria: Yes, Octapharma, Bayer, Novo Nordisk, CSL Behring, Kedrion, Genentech, BioMarin, Takeda, HEMA Biologics, and Pfizer, Consultancy (Includes expert testimony): Yes, Patents & Royalties: No, Ended employment in the past 24 months: No, Research Funding: No, Divested equity in a private or publicly-traded company in the past 24 months: No, Current equity holder in publicly-traded company: No, Current Employment: No, Current holder of stock options in a privately-held company: No, Current equity holder in private company: No, Honoraria: No