---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-26-083227"
form_type: "8-K"
ticker: "RNA"
cik: "0002093101"
company_name: "Atrium Therapeutics, Inc."
filed_at: "2026-02-27T23:59:59+00:00"
generated_at: "2026-05-15T23:16:30.980344+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Atrium Therapeutics completes spin-off from Avidity; begins trading under RNA on Nasdaq

## Summary
- Separation of Atrium Therapeutics (SpinCo) from Avidity effective Feb 26, 2026; one SpinCo share for every ten Avidity shares distributed.
- Amended License Agreement expands IP cross-licenses; Transition Services Agreement provides support services from Avidity.
- Board elected: Carsten Boess, W. Michael Flanagan, Simona Skerjanec, Troy Wilson; terms expire at first/second annual meetings.
- Executive officers: Kathleen Gallagher (CEO) and Brendan Winslow (CFO); employment agreements and compensatory plans adopted.

## SEC filing metadata
- accession: 0001193125-26-083227
- form_type: 8-K
- ticker: RNA
- cik: 0002093101
- company_name: Atrium Therapeutics, Inc.
- filed_at: 2026-02-27T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 1.01, 5.01, 5.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/2093101/000119312526083227/0001193125-26-083227-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/2093101/000119312526083227/d87849d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-26-083227
- JSON: https://secwatch.observer/filing/0001193125-26-083227.json
- Plain text: https://secwatch.observer/filing/0001193125-26-083227.txt

## Source-grounded claims
- claim_id: 076b3af353f4c5e698a278aef2405054bc5133c5
  claim: Atrium Therapeutics, Inc. completed a disposition involving Avidity Biosciences, Inc. (closed 2026-02-26).
  evidence_excerpt: Avidity Biosciences, Inc. (“Avidity”) completed the previously announced separation of all of its assets and liabilities exclusively related to its early stage precision cardiology programs
  evidence_url: https://www.sec.gov/Archives/edgar/data/2093101/000119312526083227/0001193125-26-083227-index.htm
- claim_id: cf87c733870e51fd9dd15fd3fe9a0c20a1de51a3
  claim: Atrium Therapeutics, Inc. entered into Transition Services Agreement with Avidity Biosciences, Inc. valued at Company and Avidity entered into a Transition Services Agreement pursuant to which Avidity will prov (effective 2026-02-26).
  evidence_excerpt: ☐ Item 1.01 Entry into a Material Definitive Agreement On February 26, 2026, Avidity Biosciences, Inc. (“Avidity”) completed the previously announced separation of all of its assets and liabilities exclusively related to its early stage precision cardiology programs, including ATR 1086 and ATR 1072, and certain collaboration agreements, consisting of those with Bristol-Myers Squibb Company and Eli Lilly and Company, into a separate, independent publicly traded company (the “Separation”), Atrium Therapeutics, Inc.
  evidence_url: https://www.sec.gov/Archives/edgar/data/2093101/000119312526083227/0001193125-26-083227-index.htm
- claim_id: fa798de82be4b3e13fbd3141a0e1e02c83e25595
  claim: Atrium Therapeutics, Inc. entered into Amended and Restated License Agreement with Avidity Biosciences, Inc. valued at Company entered into an Amended and Restated License Agreement with Avidity, amending the original l (effective 2026-02-26).
  evidence_excerpt: On February 26, 2026, the Company entered into an Amended and Restated License Agreement (“Amended and Restated License Agreement”) with Avidity amending the original license agreement between the Company and Avidity, dated October 25, 2025 (the “Original License Agreement”), pursuant to which the Company granted to Avidity certain exclusive and non-exclusive licenses under the Company’s platform technology and other intellectual property, and Avidity granted to the Company certain exclusive and non-exclusive licenses under certain intellectual property owned or controlled by Avidity and its subsidiaries following the Separation, as further described in the section of the Information Statement (the “Information Statement”) entitled “Business—Intellectual Property—RemainCo License Agreement” filed as Exhibit 99.1 to Amendment No. 2 to the Registration Statement on Form 10 (the “Form 10”), filed by the Company with the Securities and Exchange Commission on February 17, 2026.
  evidence_url: https://www.sec.gov/Archives/edgar/data/2093101/000119312526083227/0001193125-26-083227-index.htm

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