Myonexus’ MYO-102 Earns FDA’s Orphan Drug Status for LGMD 2D

The U.S. Food and Drug Administration has granted orphan drug designation to Myonexus Therapeutics‘ MYO-102, a gene therapy for limb-girdle muscular dystrophy type 2D (LGMD 2D), the company announced.

The FDA grants this designation to treatments with the potential to significantly improve the life of patients with rare diseases. It includes benefits such as tax deductions as an incentive to do clinical research and a period of market exclusivity in the U.S. following product approval.

LGMD 2D is a debilitating condition caused by errors in the gene that provides instructions for making the protein alpha-sarcoglycan, which is responsible for the stability of muscle fibers.

The lack of function in this protein causes inflammation, progressive loss of muscle fibers, muscle scarring, and accumulation of lipids, which lead to weakness in the lower part of the body and impaired walking ability. No treatments or cure are currently available.

MYO-102 is a gene therapy designed to restore the levels of alpha-sarcoglycan over the long term, thus addressing the underlying cause of LGMD 2D. The treatment is intended to improve the symptoms and functional ability of the patients.

Preclinical studies showed that MYO-102 was safe. The therapy significantly increased the production of alpha-sarcoglycan over baseline (pre-treatment) levels, and the protein was still present in the muscles six months after initial treatment.

“The Orphan Drug Designation from the FDA is an important milestone in the development pathway for MYO-102 and reflects its potential to address a considerable unmet medical need in treating LGMD2D,” Michael Triplett PhD, president and CEO of Myonexus, said in a press release.

“As we plan for our first systemic human clinical trial, we aim to build on the promising results of our research to date and offer hope that our gene therapy candidates may one day be able to transform the lives of patients and the families who care for them.”

Myonexus is developing four additional gene therapies to treat different types of LGMD as part of a collaboration with Sarepta Therapeutics. All five treatments use the same method of delivery (vector AAVrh.74), developed by Sarepta.

The most advanced, MYO-101, received rare pediatric disease designation from the FDA for LGMD 2E in May 2018 and is undergoing testing in a clinical trial (NCT03492346). The other therapy candidates are MYO-103 for LGMD 2C, MYO-201 for LGMD 2B, and MYO-301 for LGMD 2L.

“With ongoing research, we have increasing evidence demonstrating the potential for gene therapy. We believe this technology holds promise to address a critical unmet need in treating LGMD,” said Jerry Mendell, MD, Curran-Peters Chair of Pediatric Research at Nationwide Children’s Hospital. “The FDA’s orphan status represents an appreciation of the need and the potential of this technology to introduce the first major advance for the LGMD community.”