Long-Term Clinical, Cost Benefits of Etranacogene Dezaparvovec

New research predicts that etranacogene dezaparvovec treatment in patients with hemophilia B will provide clinical benefits and cost savings over 20 years and beyond. The study was presented at AMCP Nexus 2023.

Etranacogene dezaparvovec, sold under the brand name Hemgenix®, is an adeno-associated virus vector–based gene therapy recently approved for use in hemophilia B. The therapy has been shown to increase factor IX (FIXactivity levels, reduce the risk of breakthrough bleeding, and eliminate the need for routine FIX prophylaxis replacement therapy. However, the one-time treatment is expensive, at $3.5 million.

The authors, led by Michele Wilson, PhD, senior director of health economics at RTI Health Solutions, Research Triangle Park, N.C., sought to understand the long-term clinical and cost implications of etranacogene dezaparvovec treatment.

The group used a decision analytic model to compare two scenarios: one in which etranacogene dezaparvovec was introduced and one in which etranacogene dezaparvovec was not introduced. They loaded into the model results from the HOPE B phase 3 trial, which found that etranacogene dezaparvovec therapy was superior to prophylactic FIX with respect to annualized bleeding rate, with a favorable safety profile.

Other data added to the model included bleeding rates and adverse event rates from the HOPE B trial, as well as costs of medical care in patients with hemophilia B, such as FIX prophylaxis, disease monitoring, management of bleeding episodes, and treatment of adverse events. The model allowed the researchers to assess annual and cumulative costs, treated bleeding episodes, and joint procedures in the long term.

The model assumed that 600 people were eligible for etranacogene dezaparvovec and estimated that the treatment would prevent 11,579 bleeding events and 66 joint procedures over 20 years. In years one through five, costs with etranacogene dezaparvovec therapy (mean, $53 million annually; total, $265 million) were higher compared with costs without etranacogene dezaparvovec therapy. However, savings began in year six and continued annually through year 20 (mean, $177 million annually for a total of $2.66 billion in years six to 20).

“Initiating people with hemophilia B on etranacogene dezaparvovec sooner can produce greater and earlier savings and additional bleeds avoided,” the authors wrote. “These results may be considered a conservative estimate of the full value delivery of etranacogene dezaparvovec to the health care system, as people with hemophilia B would continue to accrue savings … beyond 20 years.”


Wilson M, McDade C, Thiruvillakkat K, Rouse R, Sivamurthy K, Yan S. Long-Term Impact of the Gene Therapy Etranacogene Dezaparvovec for the Treatment of Hemophilia B in the United States. Poster D8. Presented at AMCP Nexus 2023; Oct. 16‒19, 2023; Orlando, Fla.