---
schema_version: "secwatch.filing_event.v1"
accession: "0001664710-25-000005"
form_type: "8-K"
ticker: "KROS"
cik: "0001664710"
company_name: "Keros Therapeutics, Inc."
filed_at: "2025-01-15T23:59:59+00:00"
generated_at: "2026-05-28T01:10:28.473816+00:00"
event_type: "regulatory"
sentiment: "negative"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# Keros halts entire Phase 2 PAH trial (all doses, placebo) on pericardial effusion safety

## Summary
- Voluntary halt of all dosing in TROPOS trial, including 1.5 mg/kg and placebo arms, due to new pericardial effusion adverse events.
- Previously halted 3.0 mg/kg and 4.5 mg/kg arms on Dec 12, 2024; now entire study terminated early.
- Patients to be monitored through end-of-trial visits; investigators and FDA notified.
- Company still expects to present topline data from all treatment arms in Q2 2025.
- CEO Jasbir Seehra cited patient safety as top priority; working with FDA and other regulators.

## SEC filing metadata
- accession: 0001664710-25-000005
- form_type: 8-K
- ticker: KROS
- cik: 0001664710
- company_name: Keros Therapeutics, Inc.
- filed_at: 2025-01-15T23:59:59+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/1664710/000166471025000005/0001664710-25-000005-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1664710/000166471025000005/kros-20250115.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001664710-25-000005
- JSON: https://secwatch.observer/filing/0001664710-25-000005.json
- Plain text: https://secwatch.observer/filing/0001664710-25-000005.txt

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