---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-26-418417"
form_type: "8-K/A"
ticker: "RNA"
cik: "0002093101"
company_name: "Atrium Therapeutics, Inc."
filed_at: "2026-10-09T10:17:57+00:00"
generated_at: "2026-10-12T15:20:27.379564+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.2
calibrated_materiality_score: 0.2
confidence: "high"
source: SEC EDGAR
---

# Atrium Therapeutics corrects post-PIPE share count to 21,571,507, including make-whole spin-off shares

## Summary
- PIPE securities purchase agreement dated Oct. 7, 2026 with accredited investors covers 5,170,384 common shares plus pre-funded warrants for up to 1,134,930 shares.
- Amendment No. 1 restates shares outstanding after the offering as 21,571,507, correcting the number in the original Oct. 8, 2026 Form 8-K; no other information revised.
- That total includes shares issued to settle make-whole equity awards granted in connection with the Company's spin-off from Avidity Biosciences, Inc.
- Closing of the offering remains subject to conditions; the company flags risk that it or the PIPE Investors may fail to satisfy them.
- Amendment signed Oct. 9, 2026 by Chief Executive Officer Kathleen Gallagher.

## SEC filing metadata
- accession: 0001193125-26-418417
- form_type: 8-K/A
- ticker: RNA
- cik: 0002093101
- company_name: Atrium Therapeutics, Inc.
- filed_at: 2026-10-09T10:17:57+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.2
- calibrated_materiality_score: 0.2
- confidence: high
- sec_items: 8.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/2093101/000119312526418417/0001193125-26-418417-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/2093101/000119312526418417/d173581d8ka.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-26-418417
- JSON: https://secwatch.observer/filing/0001193125-26-418417.json
- Plain text: https://secwatch.observer/filing/0001193125-26-418417.txt

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