The FDA issued a complete response letter (CRL) to Scholar Rock’s selective anti-latent myostatin antibody apitegromab, intended for spinal muscular atrophy (SMA), citing unresolved quality control issues at a contract manufacturing site operated by Novo Nordisk. This setback delays approval despite previous confidence from the company. Scholar Rock plans to resubmit once manufacturing compliance is achieved, but no timeline was provided. This marks another hurdle for a drug anticipated to enhance skeletal muscle function in SMA patients.