---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-23-253084"
form_type: "8-K"
ticker: "ALNY"
cik: "0001178670"
company_name: "ALNYLAM PHARMACEUTICALS, INC."
filed_at: "2023-10-10T23:59:59+00:00"
generated_at: "2026-06-10T02:02:52.250662+00:00"
event_type: "regulatory"
sentiment: "negative"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# FDA rejects Alnylam's patisiran sNDA for ATTR cardiomyopathy; company abandons U.S. expansion

## Summary
- FDA issued Complete Response Letter citing insufficient evidence of clinical meaningfulness for patisiran in cardiomyopathy of ATTR amyloidosis.
- No safety, study conduct, drug quality or manufacturing issues; existing ONPATTRO polyneuropathy indication unchanged.
- Alnylam will no longer pursue expanded U.S. indication for patisiran; focus shifts to vutrisiran (HELIOS-B Phase 3) and ALN-TTRsc04.
- FDA advisory committee had voted 9:3 that benefits outweigh risks, but FDA still issued CRL.
- Company to host investor call at 8:30 a.m. ET on Oct 9, 2023 to discuss the CRL.

## SEC filing metadata
- accession: 0001193125-23-253084
- form_type: 8-K
- ticker: ALNY
- cik: 0001178670
- company_name: ALNYLAM PHARMACEUTICALS, INC.
- filed_at: 2023-10-10T23:59:59+00:00
- event_type: regulatory
- sentiment: negative
- materiality_score: 0.85
- calibrated_materiality_score: 0.85
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1178670/000119312523253084/0001193125-23-253084-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1178670/000119312523253084/d279887d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-23-253084
- JSON: https://secwatch.observer/filing/0001193125-23-253084.json
- Plain text: https://secwatch.observer/filing/0001193125-23-253084.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.