FDA Grants Orphan Drug Designation for SMA Treatment


The FDA granted orphan drug designation to Scholar Rock for its lead antibody product candidate, SRK-015, for the treatment of spinal muscular strophy (SMA).

This morning, the U.S. Food and Drug Administration (FDA) granted orphan drug designation to Scholar Rock for its lead antibody product candidate, SRK-015, for the treatment of spinal muscular atrophy (SMA).

SMA is a genetic disease that affects the central nervous system (CNS) in areas that control voluntary muscle movement, and it affects approximately 30,000 to 35,000 patients between the U.S. and Europe.

SRK-015 is a selective first-in-class inhibitor of myostatin activation. As a member of the TGF-beta superfamily of growth factors, myostatin is expressed primarily in skeletal muscle cells. Its gene’s absence is associated with an increase in muscle mass several animal species. Scholar Rock believes SRK-015’s inhibition of the activation of myostatin has the potential to promote a clinically meaningful increase in muscle mass and strength.

Nagesh Mahanthappa, PhD, President and Chief Executive Officer of Scholar Rock, expressed her excitement for the drug’s orphan designation. “We are very pleased that the FDA granted Orphan Drug Designation to SRK-015 for the treatment of patients suffering from SMA, and we appreciate that the agency’s decision came much earlier than anticipated. This designation is an important milestone in the development of our lead product candidate along the path towards a first-in-human Phase 1 clinical trial in the second quarter of 2018.”1

Preclinical data has suggested that SRK-015 helps significantly improve muscle strength and capacity, showing promise for the drug’s efficacy. In a separate preclinical study headed by the Miami Project to Cure Paralysis (MPCP) in collaboration with Scholar Rock, positive outcomes were found with SRK-015 in a spinal cord injury (SCI) model.3

The results, which were presented at the 35th Annual National Neurotrauma Symposium by Dr. Nah Bigford and Dr. Gregory Bigford, indicated positive outcomes. a reduction of fat infiltration into muscles, a decrease in muscle atrophy, and improved muscle pathology and function with SRK-015 treatments.

“The data from our collaboration with Drs. Nash and Gregory Bigford at The Miami Project to Cure Paralysis support our belief that, when applied to appropriate disease settings, highly specific inhibition of myostatin activation may result in important clinical improvements in muscle pathology and function,” Mahanthappa said about the drug’s potential in regards its preclinical data. “These data, in addition to our recent findings in a genetic model of SMA, demonstrate the potential of SRK-015 to address unmet needs in the treatment of a broad set of degenerative neuromuscular conditions."2

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  1. “Scholar Rock Granted Orphan Drug Designation by the FDA for SRK-015 for the Treatment of Patients with Spinal Muscular Atrophy.” BusinessWire. 29, Mar. 2018
  2. “Miami project presents data demonstrating therapeutic potential of SRK-015 in SCI.” EurekAlert! 10, July 2017
  3. “SRK-015.” SMA News Today.
  4. “Scholar Rock to Develop SRK-015 to Improve Muscle Function in Patients with Spinal Muscular Atrophy.” BusinessWire.
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