---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-25-210049"
form_type: "8-K"
ticker: "MBX"
cik: "0001776111"
company_name: "MBX Biosciences, Inc."
filed_at: "2025-09-22T23:59:59+00:00"
generated_at: "2026-05-17T05:59:17.967394+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# MBX Biosciences' canvuparatide meets Phase 2 primary endpoint: 63% responder rate, p=0.042, 79% at 6 months OLE

## Summary
- Primary composite endpoint met: 63% (30/48) of canvuparatide patients vs 31% (5/16) placebo at Week 12 (p=0.042).
- Open-label extension: 79% (44/56) achieved responder status at 6 months, including placebo crossovers.
- Safety: well-tolerated, no treatment-related SAEs or discontinuations; injection site reactions 19% vs 13% placebo.
- Company plans to initiate Phase 3 trial of once-weekly canvuparatide in 2026.

## SEC filing metadata
- accession: 0001193125-25-210049
- form_type: 8-K
- ticker: MBX
- cik: 0001776111
- company_name: MBX Biosciences, Inc.
- filed_at: 2025-09-22T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.85
- calibrated_materiality_score: 0.85
- confidence: high
- sec_items: 7.01, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1776111/000119312525210049/0001193125-25-210049-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1776111/000119312525210049/mbx-20250922.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-25-210049
- JSON: https://secwatch.observer/filing/0001193125-25-210049.json
- Plain text: https://secwatch.observer/filing/0001193125-25-210049.txt

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