Pfizer's gene therapy, fidanacogene elaparvovec (Beqvez), continues to demonstrate a favorable safety profile for individuals with hemophilia B, according to updated findings presented at the 66th American Society of Hematology (ASH) Annual Meeting and Exposition. The integrated analysis included data from a phase 1/2 clinical trial, a long-term follow-up study, and the pivotal phase 3 BENEGENE-2 clinical trial (NCT03861273).
Ben Samelson-Jones, MD, PhD, from the Perelman School of Medicine at the University of Pennsylvania and Children’s Hospital of Philadelphia, highlighted the reassuring nature of the data. "It should be very reassuring that there's nothing unexpected... I think what this is should be reassuring, that there's nothing has popped up that is of concern."
Key Safety Findings
The combined analysis included 15 patients from the phase 1/2 trial and 45 patients from the phase 3 trial, with follow-up periods of approximately 6 years and 3 years, respectively. The data indicated:
- No thrombotic complications
- No factor IX inhibitors
- No malignancies
Most patients experienced adverse events in the first year post-treatment, but the majority were mild and unrelated to the gene therapy vector. Notably, no infusion reactions were associated with the product's administration.
Gastrointestinal Considerations
Five serious adverse events (SAEs) involving gastrointestinal (GI) ulcers, bleeding, and anemia were reported in two participants. These events were likely secondary to steroid use without concurrent gastric protection. Samelson-Jones emphasized the importance of GI protection when administering steroids following gene therapy, recommending it as a standard practice.
Challenges in Gene Therapy Uptake
Samelson-Jones also addressed the relatively slow adoption of gene therapies for hemophilia compared to other new drugs. He attributed this to the unique logistical challenges associated with a one-time treatment costing several million dollars. Institutional processes and approvals take longer, creating a lag in uptake. He noted, "I think there's been a potential misconception that, using a metric of other new drugs, how rapidly the uptake is, and I don't think it's a good comparison, just because of the logistics of getting everything in place to do this totally new type of medication."
Despite these challenges, Samelson-Jones indicated an increase in gene therapy treatments at his institution and others in the Northeast, suggesting a gradual increase in adoption.
