Patients With Hemophilia Biding Their Time for Gene Therapy


Many surveyed participants were content with current treatments or wary of gene therapy’s adverse events and durability.

Many patients with hemophilia A/B are content with their current treatment regimens and only a minority are currently eager to undergo gene therapy, presenting a challenge in attempting to establish best practices for informed consent with the treatment mode.

Findings from a survey of adult patients with hemophilia eligible to receive approved gene therapies were presented at the 2024 ACMG Annual Clinical Genetics Meeting, March 13-15, Toronto, Canada, by Kristy Lee, MS, CGC, Professor and Genetic Counselor, UNC Chapel Hill.

The FDA approved gene therapies for adults with hemophilia B in November 2022 and for adults with hemophilia A in June 2023, with more products in the pipeline.

“Hemophilia poses a unique informed consent challenge due to having acceptable existing treatment options, lack of long-term safety and efficacy data, the potential to have multiple therapies to choose from in the future and understanding that, for now, gene therapy is likely a one-time opportunity,” Lee and colleagues wrote in the poster.

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The researchers collected survey data from 34 participants that were followed in the University of North Carolina Hemophilia Treatment Center (HTC) and completed the survey between May 2023 to February 2024. These participants had severe hemophilia A or B with or without history of inhibitors to factor replacement products and had not previously received gene therapy.

The questionnaire was completed on an iPad and consisted of 9 items, including age demographics, knowledge base, current treatment, gene therapy concerns and eagerness to undergo gene therapy.

Age ranges included 18-24 years (n = 8; 23.50%), 25-34 years (n = 6; 17.60%), 35-44 years (n = 8; 23.50%), 45-54 years (n = 7; 20.60%), 55-64 years (n = 3; 8.80%), and 65+ years (n = 2; 5.90%). Participants said that they had no knowledge (n = 7), were slightly knowledgeable (n = 9), somewhat knowledgeable (n = 10), moderate knowledgeable (sic; n = 6), or extremely knowledgeable (n = 2). Furthermore, 20 participants (58.8%) reported that they had discussed gene therapy previously with their providers and 14 (41.2%) reported they had not yet had a discussion about gene therapy in the clinic. Participants reported obtaining knowledge from their HTC providers (n=22; 64.7%), websites/online research (n=12;35.3%), bleeding disorder meetings/events (n=11;32.4%), scientific journals (n=10;29.4%), news articles (n=9; 26.5%), social media (n=5; 14.7%), conversations from relatives or other patients (n=4, 11.8%), or nowhere (n=3, 8.8%).

These participants reported concerns about gene therapy of short-term side effects (n = 9), efficacy (n = 14), cost (n = 11), long-term side effects (n = 16), need for monitoring (n = 5), or none (n = 6). In terms of readiness for gene therapy, 2 were not interested, 22 would consider in the future, and 10 were ready now. Most patients were very satisfied (n= 12; 35.3%) or satisfied (n= 12; 35.3%) with their current treatments, 3(8.8%) felt neutral, and 7 participants were very unsatisfied (20.6%), although only 2 of the latter group were interested in being dosed with gene therapy now.

Lee and colleagues concluded that the treatment landscape for hemophilia is not currently as receptive to gene therapy than other genetic conditions such as spinal muscular atrophy and Leber congenital amaurosis. Further complicating patients’ decisions are additional gene therapy products in the investigational pipeline, safety and efficacy data from which patients may be waiting to see. Additional studies are needed to understand patient knowledge and treatment expectations.

“Fortunately, gene therapy will be one of many treatment options for individuals with hemophilia A or B, and this therapy may not be appropriate or wanted by every eligible patient. At this time, the majority of patients are interested in waiting to undergo gene therapy until more information is available on long-term risks and its efficacy,” Lee and colleagues concluded. “Future work could include surveying patients pre/post education sessions by our Hemophilia Treatment Center providers to determine if responses would differ after receiving the same information on gene therapy.”

Lee K, Berkowitz C, Jackson KJ, et al. Challenges in Establishing Best Practices for Gene Therapy Informed Consent for Hemophilia A/B. Presented at: 2024 ACMG Annual Meeting; March 13-15, Toronto, Canada. Poster #246
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