Dive Brief:
- The Food and Drug Administration on Wednesday approved Regeneron Pharmaceuticals’ Pasatru to treat an uncommon bone disease, ushering in a commercial battle with an Ipsen drug that hasn’t sold well since its launch.
- Pasatru is cleared for fibrodysplasia ossificans progressiva, or FOP, a degenerative condition that causes muscles and connective tissue to turn into bones. The disease is estimated to occur in about 1 in a million people and leads to a loss of mobility.
- Development of Pasatru was slowed by a study pause following the deaths of multiple trial participants. Regeneron investigated, concluded that the treatment likely wasn’t the cause and advanced the treatment into late-stage testing. Phase 3 results announced last September showed that, over the course of a year, the drug reduced new abnormal bone formations by 90% or more when compared to a placebo.
Dive Insight:
Pasatru will have an average annual, per-patient list price of about $1.4 million based on the enrollees in clinical studies, according to a Regeneron spokesperson. The drug is dosed at either 3 or 10 milligrams per kilogram of body weight, so the cost could total anywhere between $693,000 and $2.1 million, the spokesperson said.
Known scientifically as garetosmab, the treatment is an antibody drug that blocks the activity of a protein called Activin A, which triggers excessive bone growth in people with the disease.
“This approval is monumental for our community, providing a vital new therapy that can have a significant impact on the life of someone with FOP,” said Michelle Davis, executive director of the International FOP Association, in a statement.
Pasatru will challenge Ipsen’s Sohonos, which gained an approval in 2023 despite questions about its benefits and safety. Though the drugs haven’t been tested head-to-head, Sohonos was associated with less of an impact on bone growth. Prior to Sohonos’ approval, FDA scientists also expressed concerns that patients taking the drug might be more likely than placebo recipients to experience the inflammatory “flare-ups” that come before abnormal bone growth.
Sohonos recorded sales of 21 million euros, or $24 million, in the first six months of 2026, roughly equal to the same period in 2025. Ipsen recorded an impairment charge of 279 million euros in 2024 related to slower-than-expected sales.
Pasatru’s launch comes as Regeneron is facing fresh questions about its future. The company’s biggest seller, the eye drug Eylea, is facing growing biosimilar competition. Sales of a high-dose version of Eylea haven’t yet met investor expectations and an up-and-coming cancer drug missed its goal in a key clinical trial.
