---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-25-256958"
form_type: "8-K"
ticker: "TECX"
cik: "0001681087"
company_name: "Tectonic Therapeutic, Inc."
filed_at: "2025-10-30T23:59:59+00:00"
generated_at: "2026-05-17T01:22:10.609737+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# Tectonic Therapeutic reports positive Phase 1b Part B data for TX45 in PH-HFrEF

## Summary
- Single dose of TX45 improved left heart function and pulmonary hemodynamics: PCWP -29.2%, CO +17.3%, mPAP -19.3%, TPR -29.2% mean change.
- In CpcPH patients (PVR>3 WU), PVR reduced -19.7%; PVR >2 WU group showed -10.3% mean change.
- Echocardiographic improvements at day 29: LVEF +19.4%, RVFAC +20.3%, TAPSE/SPAP +36.3% mean change.
- TX45 well tolerated with no serious or severe adverse events, no clinically significant BP changes or immune reactions.
- APEX Phase 2 trial in PH-HFpEF ongoing; topline results expected in 2026.

## SEC filing metadata
- accession: 0001193125-25-256958
- form_type: 8-K
- ticker: TECX
- cik: 0001681087
- company_name: Tectonic Therapeutic, Inc.
- filed_at: 2025-10-30T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1681087/000119312525256958/0001193125-25-256958-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1681087/000119312525256958/d30823d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-25-256958
- JSON: https://secwatch.observer/filing/0001193125-25-256958.json
- Plain text: https://secwatch.observer/filing/0001193125-25-256958.txt

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