While the U.S. FDA didn’t ask for more study data or have safety or efficacy concerns, it does want modifications to Alexion, Astrazeneca Rare Disease’s sBLA for Ultomiris (ravulizumab-cwvz) to treat adults with the rare central nervous system disease neuromyelitis optica spectrum disorder. The agency has issued a complete response letter (CRL) requesting changes to Ultomiris’ Risk Evaluation and Mitigation Strategy (REMS) to better validate patients’ meningococcal vaccination status or prophylactic administration of antibiotics before being treated.