Biogen Inc. announced that the U.S. Food and Drug Administration (FDA) has issued a Complete Response Letter (CRL) regarding the company’s supplemental New Drug Application (sNDA) for the high-dose regimen of nusinersen, used to treat spinal muscular atrophy (SMA). The FDA’s letter requested an update to the technical information included in the Chemistry Manufacturing and Controls (CMC) section of the application.
Importantly, the FDA did not identify any issues with the clinical data supporting the high-dose regimen. The agency also provided options for resolving the concerns, and Biogen plans to promptly resubmit the application using readily available information.
Priya Singhal, Head of Development at Biogen, acknowledged the unexpected outcome but emphasized the company’s ongoing commitment to making the high-dose regimen accessible to people living with SMA. Biogen is actively working with regulatory authorities worldwide to advance the high-dose option. The regimen has recently been approved in Japan and is currently under review by the European Medicines Agency (EMA) and other global regulators.