DMD treatment SAT-3247 safe in trial, shows early signs of efficacy
5 patients in study show signs of increasing muscle strength
Satellos Bioscience’s SAT-3247 was safe, well-tolerated, and showed initial signs of increasing muscle strength in five adults with Duchenne muscular dystrophy (DMD), the company said.
“We believe the findings from this Phase 1b study support our plan to advance SAT-3247 into a placebo-controlled Phase 2 trial,” Satellos CEO Frank Gleeson said in a company press release. The company said it plans regulatory submissions in the third quarter for a global Phase 2 proof-of-concept study in pediatric patients.
SAT-3247, a small molecule taken orally concurrently with steroids, was safe and well tolerated in healthy volunteers in the first portion of the Phase 1 study (NCT06565208). Its pharmacokinetics, or the way the drug moves into, through, and out of the body, translated as expected to the DMD population.
Muscular dystrophy is a group of progressive diseases caused by genetic mutations that lead to MD symptoms of muscle weakening and wasting over time. The most common form, DMD, is caused by mutations that impair the production or function of dystrophin, a protein that helps protect muscle fibers from damage during movement. Without adequate dystrophin, muscles become more vulnerable to stress and progressively deteriorate.
When muscle damage occurs, muscle stem cells typically activate and contribute to repair. This process may be disrupted in DMD. SAT-3247 aims to increase muscle stem cell activity, promoting repair and possibly slowing DMD progression. Because the pill-based therapy works independently of dystrophin, it could be used alone or alongside other treatments.
DMD treatment shows promise in animal studies
“Improvements in muscle strength have consistently been an early signal of a possible drug effect in our preclinical studies, where treatment with SAT-3247 led to notable increases in muscle force in both rodent and canine models of DMD,” Gleeson said.
The now-completed Phase 1 study consisted of two parts, a first part in healthy volunteers and a second in participants with DMD. The company noted that the study focused on adults, who are typically in the later stages of the disease, when treatment is more complex and long-term survival is less likely.
A total of 72 healthy adults participated in the first part of the study, with none experiencing moderate or severe side effects with one or multiple doses of SAT-3247, according to Satellos.
In the second part, five adults with genetically confirmed DMD, ranging in age from 20 to 27 and all on prescribed steroids, received SAT-3247 for 28 days. The goal was to evaluate the treatment’s safety, its pharmacokinetics, and explore early signs of efficacy.
As in the first part, the medication appeared to be safe and well tolerated, and its pharmacokinetics translated as expected to the DMD participants.
On average, patients’ grip strength doubled over the course of the trial, from two to four kilograms, suggesting a possible clinical effect.
“Given the short 28-day treatment window, the severity and variability of disease in this population, who have limited remaining muscle, we are encouraged by these initial data — particularly, the apparent trend of improved grip strength,” Gleeson said. “We look forward to engaging with regulators and sharing more about our next steps.”
Satellos plans to start an 11-month follow-up study, which has been approved by an ethics committee in Australia. The first patient is expected to be dosed in in the third quarter of 2025, once the clinical site is ready. The study will use MRI to look for muscle changes and check grip strength every three months, along with other functional and biomarker tests, to see if improvements continue.
U.S. regulators have designated the DMD treatment as an orphan drug and granted it rare pediatric disease status. These categories provide incentives to candidate therapies for rare disorders.
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