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Unknown — FDA Complete Response Letter (BLA 761303)

Issued to Regeneron Pharmaceuticals, Inc.. Application reviewed but not approved; deficiencies must be corrected.

Application

BLA • 761303

Product

Unknown

Company

Regeneron Pharmaceuticals, Inc.

Review center

CBER

Stage

Final Decision

Response due

March 22, 2025

Assyro regulatory brief

Free

What did FDA decide for Unknown?

Source facts and Assyro context are separated so you can scan the action quickly without treating analysis as an FDA conclusion.

Verify in source

Source facts

FDA's complete response letter contains source-text evidence related to Labeling, packaging, and proprietary name, Clinical efficacy and substantial evidence. Theme counts identify where the letter discusses a topic; they do not replace review of the exact redacted letter.

Key details in this letter

  • 1Labeling, packaging, and proprietary name: 20 source-text matches.
  • 2Clinical efficacy and substantial evidence: 1 source-text match.
Labeling, packaging, and proprietary nameClinical efficacy and substantial evidence

Suggested next step

Review the exact redacted FDA letter and address each stated deficiency before resubmission.

Open the document workspace

Built from structured FDA metadata and deterministic source-text signals. Topic matches are navigation aids, not legal or regulatory conclusions. Verify material decisions against the original FDA document.

FDAPDFUpdated Jul 30, 2026

FDA source document

Read the full FDA complete response letter (PDF)

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Common questions about the Unknown complete response letter

What does this complete response letter mean for Unknown?

Application reviewed but not approved; deficiencies must be corrected. Requires resubmission addressing deficiencies. FDA issued this letter to Regeneron Pharmaceuticals, Inc. on March 22, 2024.

What is BLA 761303?

BLA 761303 is the application under which FDA issued this complete response letter for Unknown to Regeneron Pharmaceuticals, Inc.. It was reviewed by FDA CBER. The letter is dated March 22, 2024.

What happens after an FDA complete response letter?

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.