Scholar Rock announces data from Phase 2 TOPAZ trial extension period

Scholar Rock 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 receiving survival motor neuron-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. Substantial and Sustained Gains in Motor Function Observed Over the Extended Treatment Period: Nonambulatory patients experienced substantial and sustained gains in Hammersmith Functional Motor Scale-Expanded and Revised Upper Limb Module scores over the 36-month extended treatment period from baseline. For the 36-month data, an observed case analysis was conducted, which pooled data for all nonambulatory patients and was based upon the available data. These analyses exclude data for patients post scoliosis surgery. Improvement in Patient-Reported Outcomes Consistent with Improvements in Motor Function: Nonambulatory patients had improvements in PEDI-CAT and PROMIS-Fatigue that were consistent and sustained at 36 months. The mean change in PEDI-CAT daily activity domain from baseline at 36 months was 2.2, indicating an improvement in the ability to perform daily activities. The mean change in PROMIS-Fatigue from baseline at 36 months was -4.6, indicating a decline in fatigue. These improvements in PEDI-CAT and PROMIS-Fatigue were generally consistent with improvements in motor function across the 36 months of the study period. Consistent Safety Data: Treatment-emergent adverse events at 36 months were consistent with previous reports at 12 and 24 months, with no new findings after an aggregate of 198 patient-years of exposure. TEAEs were mostly mild-to-moderate in severity, and generally consistent with the underlying patient population and background therapy. The five most common TEAEs were headache, pyrexia, COVID-19, nasopharyngitis, and upper respiratory tract infection. No deaths or suspected unexpected serious adverse reactions or hypersensitivity reactions were observed with apitegromab at 36 months. A total of 21 serious TEAEs were reported over the 36-month treatment period. No patients displayed positive titers for apitegromab antibodies. More than 90 percent of nonambulatory patients remained on treatment in the extension study.