A one-time gene therapy for hemophilia B has arrived in Detroit, offering some patients a shot at escaping the weekly infusions that have ruled their calendars for decades. One Detroit-area man who was diagnosed at age 2 received the treatment late last year and says the difference is striking. Karmanos Cancer Institute reports it is the first freestanding cancer center in the country to provide the therapy, and that this patient is among the earliest people nationwide to get it. The treatment is aimed at adults with severe hemophilia B who have been relying on routine factor prophylaxis.
"It was a Band-Aid, that's all it was," patient Stephen Werner told FOX 2 Detroit, describing years of weekly factor injections before the gene therapy. Werner, diagnosed with hemophilia B as a toddler, received an hour-long IV infusion at the end of 2025 and says he is no longer on routine prophylaxis. He told FOX 2 that the change has been life-altering and that he now feels "fantastic."
How the one-time infusion works
The commercially available product, HEMGENIX (etranacogene dezaparvovec), uses an adeno-associated viral vector to deliver a functioning copy of the factor IX gene to the liver so the body can make its own clotting factor, according to Karmanos Cancer Institute. Patients are monitored during and after the infusion for infusion-related reactions and for elevations in liver enzymes, and clinicians may prescribe short-term steroids if those enzymes rise. Karmanos officials said staff completed specialized training before rolling out the therapy and that eligibility is limited to adults with severe bleeding who previously used factor prophylaxis.
What the long-term data show
Long-term results from the pivotal HOPE-B study, published in the New England Journal of Medicine and summarized by CSL Behring, showed that 94% of trial participants remained free of continuous prophylaxis five years after a single infusion and that mean factor IX activity stayed around 36% at year five, according to CSL Behring. The study also found about a 90% reduction in annualized bleeding rate and a generally favorable safety profile, while still emphasizing the need for ongoing liver monitoring and careful follow-up. Clinicians caution that individual responses vary and that some patients may not see the same level of benefit, so screening and long-term oversight remain crucial.
Local rollout and access
Karmanos announced in March that its Detroit infusion marked the center’s entry into providing the commercially available gene therapy, and the institute’s blog notes the first Karmanos patient received treatment on Oct. 28, 2025. According to Karmanos Cancer Institute, the center spent months on staff training and coordination across pharmacy and hematology teams to prepare for the program. Other Michigan providers have begun offering HEMGENIX as well, with Children’s Hospital of Michigan reporting that it administered the state’s first commercial infusion in July 2025, per Children’s Hospital of Michigan, signaling cautious but steady adoption across regional centers.
The therapy’s list price at approval turned heads. HEMGENIX was reported to cost about $3.5 million per dose, and that sticker shock has heavily influenced debates over access, payment models and the pace of rollout, according to national coverage by CNN. Hospitals that offer the infusion say they work with manufacturers and insurers on coverage pathways and patient assistance when needed, but uptake has been deliberate while clinicians and payers build long-term follow-up frameworks.
For patients and families, trading weekly or multiple infusions for a potential one-time treatment represents relief, along with a new set of tradeoffs to sort through. Werner captured the shift in plain language, saying "I feel fantastic" in his interview with FOX 2 Detroit, while local hematologists stress that careful screening, liver surveillance and long-term registries will be essential as more patients gain access to the therapy.
