---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-25-122511"
form_type: "8-K"
ticker: "TECX"
cik: "0001681087"
company_name: "Tectonic Therapeutic, Inc."
filed_at: "2025-05-19T23:59:59+00:00"
generated_at: "2026-05-21T01:48:25.714249+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Tectonic TX45 Phase 1b in PH-HFpEF shows 19% PCWP reduction, sustained 29-day effects

## Summary
- Single IV dose of TX45 reduced PCWP by 19.0% [95% CI, -26.1% to -11.9%] in 19-patient cohort.
- In CpcPH subgroup (PVR≥2), PVR decreased 32.0% (≥2) and 35.5% (≥3); 30%+ reduction in PVR.
- Echocardiogram showed sustained improvements in TAPSE/SPAP and RVFAC for 29 days post-dose.
- Cardiac output increased 18.5% overall; greater improvement in patients with higher baseline PVR.
- No serious or severe adverse events; Phase 1b Part B in HFrEF topline expected H2 2025.

## SEC filing metadata
- accession: 0001193125-25-122511
- form_type: 8-K
- ticker: TECX
- cik: 0001681087
- company_name: Tectonic Therapeutic, Inc.
- filed_at: 2025-05-19T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1681087/000119312525122511/0001193125-25-122511-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1681087/000119312525122511/d939029d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-25-122511
- JSON: https://secwatch.observer/filing/0001193125-25-122511.json
- Plain text: https://secwatch.observer/filing/0001193125-25-122511.txt

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