Highlights From the 66th ASH Annual Meeting and Exposition
Use of Fidanacogene Elaparvovec, a Gene Therapy Vector, to Deliver a Stable, Fully Functional Human Factor IX Transgene for the Treatment of Hemophilia B: A Combined Analysis of Safety
Presenting Author: Benjamin Samelson-Jones, MD, PhD
Ben Samelson-Jones, MD, PhD1,2; Laurent Frenzel, MD, PhD3*; Kaan Kavakli4*; Adam Cuker, MD5; Jerome M. Teitel, MD6; Pengling Sun7*; Lisa J Wilcox, PhD8*; Francesca Biondo, MD9*; Benjamin Hutter, MBBS, BSc10*; John McKay, MS11*; Delphine Agathon, PhD12*; and Frank Plonski, MA, RN, BS13*
- Children's Hospital of Philadelphia, Philadelphia, PA
- University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
- Department of Haematology, Institut Necker, Paris, France
- Division of Hematology, Department of Pediatrics, Ege University Faculty of Medicine, Izmir, Turkey
- Department of Medicine and Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Division of Hematology, St. Michael's Hospital, University of Toronto, Toronto, ON, Canada
- Pfizer Inc, Cambridge, MA
- Senior Director – Global Medical Affairs at Pfizer, Pfizer, Toronto, ON, Canada
- Pfizer S.r.l., Rome, Italy
- Pfizer Inc, London, United Kingdom
- Pfizer Inc, Pearl River, NY
- Pfizer Inc, Paris, France
- Pfizer Inc, Collegeville, PA
Data Points
Figure 1: Clinical Trial Results
Data from clinical trials of fidanacogene elaparvovec in adult males (≥18 years) with hemophilia B (FIX ≤ 2%) have demonstrated a favorable safety profile over a median follow-up of 5.8 years (Phase 1/2a) and 2.8 years (BENEGENE-2, Phase 3). Among 60 participants, 87% experienced adverse events (AEs), primarily mild-to-moderate elevations in alanine transaminase (ALT; 20%) and nasopharyngitis (18%), while 8% reported serious AEs. Corticosteroids were administered to 52% of participants during the first year for transaminase elevations or reduced FIX levels, with no additional treatments required thereafter. No FIX inhibitors, hepatic malignancies, or unresolved gene therapy-related transaminase elevations were observed. Liver abnormalities, including steatosis and cirrhosis, were unrelated to the therapy. Long-term follow-up will assess long-term outcomes and will be ongoing for up to 15 years.
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