OBJECTIVES: Novel gene therapies may offer important treatment opportunities for patients with rare genetic diseases such as dystrophic epidermolysis bullosa (DEB). DEB has a mild autosomal dominant variant and a severe autosomal recessive form that is associated with severe impacts to quality and length of life. Beremagene geperpavec (B-VEC) was FDA-approved in the United States (US) in May 2023 for both forms of DEB. While this therapy offers substantial benefits for autosomal recessive patients, there is greater uncertainty about its benefit in patients with autosomal dominant disease, who were largely excluded from the pre-approval clinical studies. We estimated expenditures on B-VEC therapy using different scenarios of the eligible population for treatment.

METHODS: We estimated the number of prevalent and incident cases of DEB over a three-year period using US national registry data, and healthcare spending on B-VEC during the first three years of treatment assuming an annual cost of $300,000 per patient (consistent with the manufacturer-reported range). We also estimated lifetime total costs of treatment.

RESULTS: For patients with autosomal dominant or autosomal recessive DEB treated with B-VEC in the first year, estimated spending in the US was $268 million (range: $178-$356 million). Over a three-year period estimated spending was $805 million (range: $536 million-$1.1 billion). If the indication were narrowed to only autosomal recessive patients, estimated three-year spending would be $399 million (range: $266-$533 million). Estimated lifetime total per patient costs for autosomal recessive disease and autosomal dominant disease amounted to $15 million (range: $10-$20 million) and $16 million (range $11-$22 million), respectively.

CONCLUSIONS: B-VEC is an important new therapy for DEB, but the eligible population is a key factor in the ultimate costs borne by payers. The FDA should carefully consider whether it is appropriate to expand such products’ approvals beyond the populations in which they were tested.