Issued to Biogen, Inc.. Application reviewed but not approved; deficiencies must be corrected.
Issued
September 22, 2025Application
NDA 505b1 • 209531
Product
SPINRAZA
Company
Biogen, Inc.
Stage
Final Decision
Assyro regulatory brief
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FDA's complete response letter contains source-text evidence related to Labeling, packaging, and proprietary name, Clinical efficacy and substantial evidence, Safety and adverse events, Nonclinical evidence. Theme counts identify where the letter discusses a topic; they do not replace review of the exact redacted letter.
Review the exact redacted FDA letter and address each stated deficiency before resubmission.
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Application reviewed but not approved; deficiencies must be corrected. Requires resubmission addressing deficiencies. FDA issued this letter to Biogen, Inc. on September 22, 2025.
NDA 209531 is the application under which FDA issued this complete response letter for SPINRAZA to Biogen, Inc.. The letter is dated September 22, 2025.
FDA will not approve the application in its present form. The sponsor can resubmit after addressing every deficiency listed in the letter — which starts a Class 1 (two-month) or Class 2 (six-month) resubmission review clock — withdraw the application, or request an opportunity for a hearing.