Mirum plans 2025 Phase 2 trial testing fragile X treatment
Company recently acquired global rights to therapy
A Phase 2 clinical trial to test MRM-3379, an experimental oral treatment for fragile X syndrome, is expected to launch in 2025.
Mirum Pharmaceuticals announced the plan in a company press release reporting financial results and business updates. It didn’t provide details on the trial’s design or location.
In October, Mirum acquired global rights to develop, produce, and market MRM-3379, previously known as ENT-3379, from Enthorin Therapeutics and Dart Neuroscience. In addition to an upfront payment of $7.5 million to the two companies, Mirum may be required to make milestone payments of up to $217.5 million plus royalties on any future sales.
With the addition of the Phase 2-ready MRM-3379 candidate, Mirum’s growing commercial portfolio of treatments for rare neurological diseases with a genetic cause is “taking shape,” said Chris Peetz, Mirum’s CEO.
Fragile X syndrome is a neurodevelopmental disease caused by mutations in FMR1, a gene responsible for producing the FMRP protein, which regulates the production of several other proteins involved in nerve cell communication. The disease can result in a range of symptoms that are usually milder in female patients than in males. These range from developmental delays and learning difficulties to anxiety and hyperactive or autistic behavior.
Oral molecule designed to block problem enzyme
About 50,000 male patients are thought to live with fragile X in the U.S. and European Union, according to an estimate presented by Mirum in a recent company’s corporate presentation. However, there are currently no approved treatments for the disease.
MRM-3379 is an orally available molecule designed to selectively block phosphodiesterase 4D (PDE4D), an enzyme that is most active in regions of the brain that are important for learning, memory, and emotional regulation.
PDE4D is involved in the breakdown of cAMP, a key signaling molecule between nerve cells that is found at lower-than-normal levels in people with fragile X syndrome.
By suppressing PDE4D’s activity, the experimental therapy is expected to increase cAMP levels, which may help to rebuild the network of nerve cells that communicate in the brain and that is affected in the disease. Ultimately, this may help ease fragile X symptoms.
Previous studies have shown that treatment with MRM-3379 results in drug levels that are about five times higher in the brain than in the blood, according to the company. The treatment has also been shown to be effective in preclinical models of memory, and was well tolerated when given as single or multiple ascending doses in Phase 1 clinical trials, Mirum said in its presentation.
About the Author
