---
schema_version: "secwatch.filing_event.v1"
accession: "0001664710-24-000102"
form_type: "8-K"
ticker: "KROS"
cik: "0001664710"
company_name: "Keros Therapeutics, Inc."
filed_at: "2024-12-12T23:59:59+00:00"
generated_at: "2026-05-29T04:08:05.944728+00:00"
event_type: "regulatory"
sentiment: "negative"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# Keros halts two high-dose arms of Phase 2 PAH trial after pericardial effusion

## Summary
- Voluntarily halted dosing in 3.0 mg/kg and 4.5 mg/kg cibotercept arms in ongoing TROPOS trial.
- Decision based on unanticipated pericardial effusion adverse events; safety review triggered.
- 1.5 mg/kg treatment arm continues dosing after DMC and internal risk-benefit assessment.
- Topline data from all treatment arms still expected in Q2 2025; FDA and other regulators notified.
- CEO Jasbir Seehra stated patient safety is top priority; Company investigating findings.

## SEC filing metadata
- accession: 0001664710-24-000102
- form_type: 8-K
- ticker: KROS
- cik: 0001664710
- company_name: Keros Therapeutics, Inc.
- filed_at: 2024-12-12T23:59:59+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/1664710/000166471024000102/0001664710-24-000102-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1664710/000166471024000102/kros-20241212.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001664710-24-000102
- JSON: https://secwatch.observer/filing/0001664710-24-000102.json
- Plain text: https://secwatch.observer/filing/0001664710-24-000102.txt

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