New 36-Month Apitegromab Extension Data Reinforce Long-Term Substantial and Sustained Improvement of Motor Function in Phase 2 TOPAZ Trial Patients with Nonambulatory Spinal Muscular Atrophy

Scholar Rock (NASDAQ: SRRK), a Phase 3, clinical-stage biopharmaceutical company focused on the treatment of serious diseases in which protein growth factors play a fundamental role, today announced new data from the Phase 2 TOPAZ trial extension period evaluating patient outcomes at 36 months of treatment with apitegromab. These data showed that continued treatment with apitegromab over the extended treatment period was associated with substantial and sustained improvement in motor function, as well as improvements in patient-reported outcome measures in patients with nonambulatory Types 2 and 3 spinal muscular atrophy (SMA) receiving survival motor neuron (SMN)-targeted therapy. Detailed results were presented today by Thomas Crawford, M.D., of Johns Hopkins Medicine, and the lead principal investigator of the TOPAZ trial, during two podium presentations at the Cure SMA Research & Clinical Care Meeting in Orlando, Florida.

“These promising long-term data highlight the therapeutic potential of muscle-targeted therapies, such as apitegromab, to help those with SMA address persistent weakness,” said Dr. Crawford. “While SMN-targeted therapies play an important role in preventing further loss of motor neurons, many people still experience persistent or progressive symptoms due to preexisting motor neuron degeneration. Incorporating a muscle-targeted therapy with apitegromab’s clinical profile into the treatment paradigm could allow patients to sustain or potentially achieve new gains in motor functioning.”

“We are excited to share these new Phase 2 data that support apitegromab’s long-term durability of effect and consistent tolerability and safety profile. The results further strengthen our confidence in apitegromab’s therapeutic potential for patients with SMA, as well as validate Scholar Rock’s unique approach to selectively inhibiting the pro and latent forms of myostatin,” said Jay Backstrom, M.D., MPH, President and Chief Executive Officer of Scholar Rock. “In addition to the sustained benefit observed with consistent HFMSE scores, we saw continued improvement in RULM scores, and reductions in fatigue as reported by patients—all of which can be important factors in performing activities of daily living. We remain committed to advancing the standard of care for people with SMA, and we look forward to sharing updates on our pivotal Phase 3 SAPPHIRE trial, which we anticipate will complete enrollment in the third quarter of 2023.”