FDA Puts Resolaris on Fast Track as Potential Therapy for Limb Girdle Muscular Dystrophy 2B

The U.S. Food and Drug Administration (FDA) has granted Fast Track designation to Resolaris as a potential treatment for limb girdle muscular dystrophy 2B (LGMD2B).

The FDA also removed its partial clinical hold on a dosing ceiling for Resolaris in clinical trials, the drug’s developer, aTyr Pharma, announced in press release.

Resolaris is the first  drug candidate for LGMD2B to received Fast Track status, which gives a company incentives to speed the development of drugs intended to treat serious or life-threatening diseases, and includes the possibility of accelerated approval. LGMD2B is a type of inherited muscular dystrophy that causes distal muscle weakness, especially involving the calf muscles in the lower limbs.

“This Fast Track designation, which is granted to drug candidates addressing serious conditions and that demonstrate the potential to address unmet medical needs, represents another step forward for our first product candidate based on the Physiocrine pathway,” said John Mendlein, PhD, chief executive officer of aTyr Pharma. “Combined with our Phase1b/2 data in LGMD2B, adult facioscapulohumeral muscular dystrophy (FSHD) and early onset FSHD patients, we believe we are building a clinical and regulatory foundation for future development of Resolaris to treat patients across multiple rare genetic myopathies with an immune component.”

aTyr previously reported data from a completed open-label, dose escalation Phase 1b/2 (NCT02579239) clinical trial that assessed the safety and biological activity of Resolaris up to 3.0 mg/kg biweekly in patients with Limb Girdle (LGMD2B) and facioscapulohumeral muscular dystrophies.

According to aTyr, Resolaris has consistently shown to have a favorable safety profile without signs of immuno-suppression of circulating immune cells.

Trial data also showed that seven out of nine LGMD2B patients (78 percent) had improved muscle function of 6.2% compared to baseline (as measured by the manual muscle test, MMT), the company reported. This was observed 14 weeks post-treatment.

“We appreciate the FDA’s responsiveness to our request to remove the partial clinical hold that provides dosing flexibility based on our data for Resolaris,” Sanjay Shukla, MD, MS, chief medical officer of aTyr Pharma said. “We also believe that during our safety and dose ranging Phase 1b/2 clinical trials we have potentially identified a dose for the next phase of clinical development with a favorable safety profile and potential clinical activity across different rare muscle indications.”

Resolaris is a first-in-class intravenous protein being developed for the treatment of rare myopathies with an immune component, and it is aTyr’s first Physiocrine-based product candidate in the clinic.

Resolaris was designed an Orphan Drug Designation by the European Medicines Agency (EMA) in February 2015, and by the U.S. Food and Drug Administration (FDA) in April 2015, as treatment for facioscapulohumeral muscular dystrophy (FSHD).