SMA Newsroom

Feb 27, 2019

Scholar Rock Announced Positive Interim Results from Phase 1 Trial of SRK-015 in Healthy Volunteers and Updates on Future Development Plans

Scholar Rock announced positive interim results from the ongoing Phase 1 clinical trial of its potential muscle-targeted SMA therapy, SRK-015 in healthy adult volunteers.

What is SRK-015?

SRK-015 is an antibody which inhibits the activities of a muscle protein called myostatin. This protein restricts muscle mass and strength. Scholar Rock believes that by preventing the activation of myostatin, a clinically meaningful increase in muscle mass and strength will be achieved. The U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation (ODD), and the European Medicines Agency (EMA) has granted Orphan Medicinal Product Designation, to SRK-015 for the treatment of SMA.

What do the interim results of the phase 1 trial show?

The Phase 1 clinical trial was designed to evaluate the safety and tolerability of SRK-015 in healthy volunteers and inform dosing for a Phase 2 trial in people with SMA. The results show that SRK-015 is well tolerated and has no apparent safety signals.  They also show that SRK-015's mechanism of action works by successfully engaging with myostatin. Combined, this data supports the start of a Phase 2 clinical trial in patients with SMA.

“We are very excited with the progress to date in the Phase 1 trial of SRK-015 as we continue to work towards developing our lead antibody candidate as a potential first muscle-directed therapy for the treatment of SMA,” said Yung Chyung, M.D., Chief Medical Officer of Scholar Rock. “We look forward to initiating the Phase 2 proof-of-concept trial to evaluate SRK-015’s potential to address the functional deficits that continue to represent a significant unmet need in SMA.”

Overview of plans for the Phase 2 (TOPAZ) trial

Scholar Rock plans to initiate a Phase 2 proof-of-concept clinical trial to assess the safety and efficacy of SRK-015 in patients with Type 2 and Type 3 SMA by the end of the first quarter of 2019. The trial will include three cohorts, each representing a distinct subpopulation of patients.  A total of 50-60 patients are planned to be enrolled in the Phase 2 trial and all patients will receive SRK-015 dosed once every four weeks either on its own or in conjunction with an approved SMN upregulator therapy (Spinraza™).  The primary efficacy endpoints will measure motor function through clinically meaningful outcome measures validated in SMA, such as the Hammersmith Functional Motor Scale Expanded (HFMSE) in non-ambulatory SMA and the Revised Hammersmith Scale (RHS) in ambulatory SMA, over a 12-month treatment period.   Scholar Rock plans to provide additional details on the trial design at the time of initiating patient dosing in the second quarter of 2019.