CAMBRIDGE, Mass., Sept. 23, 2025 (GLOBE NEWSWIRE) -- Biogen Inc. (Nasdaq: BIIB) today announced that the U.S. Food and Drug Administration (FDA) issued a Complete Response Letter (CRL) for the Company’s supplemental New Drug Application (sNDA) for the high dose regimen of nusinersen for the treatment of spinal muscular atrophy (SMA). The FDA letter requested an update to the technical information be included in the Chemistry Manufacturing and Controls (CMC) module of the sNDA. The letter did not cite any de ...