Dive Brief:

• Entrada Therapeutics lost more than half its value Thursday after the company reported early data for an experimental Duchenne muscular dystrophy treatment that fell short of analyst expectations.
• The company said results from the Phase 1/2 study were positive, with the RNA-based therapy showing favorable safety and tolerability. Researchers also saw indications that the medicine, dubbed ENTR-601-44, could help patients with the muscle-weakening disease rise off the floor faster than those on placebo.
• But investors zeroed in on how much the treatment could increase production of dystrophin, a protein that is critical for muscle protection and doesn’t appear at adequate levels in Duchenne patients. The study showed an increase of 2.36%, compared with analyst expectations of 10% or more. Shares of the company have subsequently tumbled 55%.

Dive Insight:

Investors hoping for signs that Entrada’s medicine will be able to rival similar drugs that are further along were likely disappointed by the results released Thursday. Avidity Biosciences, which was scooped up by Novartis in a $12 billion deal that closed in February, reported last year a 25% increase in dystrophin production for its experimental “del-zota” therapy and made plans to seek approval.

Entrada will now need to look to higher doses of its drug to compete, and the time needed to conduct the research “will augment first-to-market advantages for del-zota,” assuming Novartis succeeds in the regulatory process, William Blair analyst Myles Minter wrote in a note to clients.

Even so, Minter found the time-to-rise data for ENTR-601-44 “intriguing.”

Duchenne muscular dystrophy is caused by mutations in a gene that stifle production of the vital dystrophin protein, causing progressive muscle weakening that can eventually affect breathing and weaken the heart. The disease, which affects about 41,000 people in the U.S. and Europe, usually arises in childhood and mostly affects males.

Entrada’s drug, like del-zota, is designed to treat a subset of Duchenne patients with mutations involving “exon 44,” a specific part of a defunct gene. The therapy is designed to “skip” this section and help the body produce a shorter, still-functional form of dystrophin.

Development of the medicine has been bumpy. The Food and Drug Administration in 2022 halted the company’s plans to begin human trials in the U.S. — a hold that lasted until February 2025. Participants in the study released Thursday, known as ELEVATE-44-201, received the treatment at sites in the U.K. and European Union.