FDA names once-daily (Z)-endoxifen an orphan drug for Duchenne
New designation expected to encourage further research into oral therapy
The U.S. Food and Drug Administration (FDA) has granted orphan drug designation to (Z)-endoxifen for Duchenne muscular dystrophy (DMD), providing Atossa Therapeutics with incentives to encourage further research into its DMD treatment candidate.
The company said it plans to continue working closely with the FDA as it develops the once-daily oral therapy. In a company press release announcing the new status, Atossa said that it will share updates as the program moves forward.
It’s the second rare disease status awarded to the therapy by the FDA.
“In addition to the previously received rare pediatric disease designation, orphan drug designation for (Z)-endoxifen in Duchenne muscular dystrophy is an important milestone for Atossa as we move forward developing (Z)-endoxifen for this serious and debilitating disease,” said Steven C. Quay, MD, PhD, Atossa’s president and CEO.
Orphan drug designation is granted to treatments for rare diseases, which in the U.S. means those affecting fewer than 200,00 people. It offers benefits such as guidance from the FDA during development and, if the treatment is approved, a period of seven years during which similar medications cannot be marketed for the same use. The goal is to encourage companies to invest in treatments that may otherwise be too difficult or costly to develop.
Duchenne muscular dystrophy, known for short as DMD, makes muscles weaken over time. It is caused by mutations in the gene that encodes dystrophin, a crucial protein that protects muscle fibers from damage. Muscle weakness usually begins early in life. As the disease progresses, children may lose the ability to walk and may develop breathing and heart complications. Current DMD-specific treatments may not work or are not indicated for all patients.
Developer exploring (Z)-endoxifen as add-on therapy for DMD
(Z)-endoxifen is an oral small molecule being developed as a once-per-day treatment for DMD. It is a selective estrogen receptor modulator/degrader, which means that it can alter how estrogen receptors function while also triggering their degradation. These receptors are important in how muscle cells grow and repair after damage.
Atossa is exploring (Z)-endoxifen as a potential add-on treatment for Duchenne muscular dystrophy across all disease-causing genetic mutations.
Besides this type of muscular dystrophy, the company is testing (Z)-endoxifen as a potential cancer treatment. Earlier Phase 1 and Phase 2 clinical studies have shown that (Z)-endoxifen can delay tumor progression and stabilize the disease compared with a related treatment called tamoxifen. Tamoxifen, a selective estrogen receptor modulator, but not a direct degrader, has also been tested, though unsuccessfully, for DMD.
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