The FDA cleared Scholar Rock’s myostatin inhibitor apitegromab (Isembyld) for spinal muscular atrophy, authorizing use alongside existing SMN-targeted therapies in eligible adults and children age 2 and older. The approval follows a delay driven by manufacturing issues at a fill-finish facility, setting up another shift in the SMA treatment landscape. Isembyld is the first commercial SMA therapy designed to directly target muscle tissue rather than the underlying SMN biology. In the company’s studies, adding Isembyld improved motor outcomes compared with standard care alone, giving clinicians an additional lever to try to improve function as patients remain on SMN-based regimens. Industry focus now shifts to launch execution and supply stabilization, since the prior manufacturing hurdles were directly tied to the FDA review timeline. Analysts have also highlighted Isembyld’s potential peak revenue, contingent on uptake and continued production readiness.