European regulators back new DMD gene therapy with key status

Regulators in the European Union have granted orphan drug designation to SGT-003, a gene therapy for Duchenne muscular dystrophy (DMD) that’s being developed by Solid Biosciences.

The treatment candidate, already awarded orphan drug status in the U.S., aims to preserve muscle health in boys with DMD.

This new designation, by the European Commission, is granted to investigational treatments that have the potential to meaningfully improve care for rare diseases, specifically defined as conditions that affect no more than 5 of every 10,000 people in the EU. With this designation, Solid will gain access to several regulatory perks, including a guaranteed decade of market exclusivity if the therapy is ultimately approved in the EU.

“This Orphan designation recognizes SGT-003’s potential to address the significant unmet need in Duchenne muscular dystrophy and supports our firm commitment to advancing SGT-003 for patients globally,” Jessie Hanrahan, PhD, Solid’s chief regulatory and preclinical operations officer, said in a company press release.

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DMD is caused by mutations in the gene that encodes dystrophin, a protein that’s vital for muscle health. People with DMD produce little to no functional dystrophin. As a result, muscles acquire excessive damage over time, ultimately driving disease symptoms.

SGT-003 is designed to deliver a miniaturized but functional version of dystrophin, called microdystrophin, to muscle cells, thereby preserving muscle health and slowing DMD progression.

2 clinical trials now testing gene therapy in DMD boys

In addition to its orphan drug status in the U.S., the therapy was previously granted fast track and rare pediatric disease designations in that country. It’s also been awarded Innovation Passport designation in the U.K., which likewise aims to incentivize and support the development of potentially important therapies.

The new EU status was awarded after a positive opinion from the European Medicines Agency Committee for Orphan Medicinal Products, per Solid.

The developer is now sponsoring two clinical trials testing SGT-003 in boys with Duchenne.

A Phase 1/2 study called INSPIRE DUCHENNE (NCT06138639) is testing the therapy in various groups of boys with DMD, ranging in age from infants to teenagers. Early data from that study have indicated that SGT-003 worked as expected to increase the levels of microdystrophin and preserve muscle health in a subset of boys with DMD. Additional participants are still being recruited at sites in the U.S., Italy, Canada, and the U.K.

The other trial, IMPACT DUCHENNE (NCT07160634), is a Phase 3 study testing SGT-003 against a placebo in boys with DMD, ages 7 to 11, who are able to walk. The study’s main goals are to see if the gene therapy can significantly improve standard measures of physical function. Recruitment for this trial, expected to enroll 80 participants, is ongoing at sites in Canada and Australia.