---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-26-336841"
form_type: "8-K"
ticker: "MBX"
cik: "0001776111"
company_name: "MBX Biosciences, Inc."
filed_at: "2026-08-06T12:03:59+00:00"
generated_at: "2026-08-06T12:05:30.744818+00:00"
event_type: "earnings"
sentiment: "positive"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# MBX Biosciences Q2 net loss $37.1M; cash $418.6M; canvuparatide Phase 3 recruiting; MBX 4291 7% weight loss

## Summary
- Net loss of $37.1M for Q2 2026 vs $19.4M in Q2 2025; R&D expenses rose to $31.0M from $17.7M.
- Cash, cash equivalents and marketable securities of $418.6M as of June 30, 2026; expected to fund operations into 2029.
- Phase 3 oPTimize trial of once-weekly canvuparatide in hypoparathyroidism now recruiting; sites activated.
- MBX 4291 Phase 1 data: 7% mean weight loss at 8 weeks in first MAD cohort; 12-week MAD data on track for Q4 2026.
- Steve Hoerter appointed Chairman and CEO; John Smither appointed CFO.

## SEC filing metadata
- accession: 0001193125-26-336841
- form_type: 8-K
- ticker: MBX
- cik: 0001776111
- company_name: MBX Biosciences, Inc.
- filed_at: 2026-08-06T12:03:59+00:00
- event_type: earnings
- sentiment: positive
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 2.02, 7.01, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1776111/000119312526336841/0001193125-26-336841-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1776111/000119312526336841/mbx-20260806.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-26-336841
- JSON: https://secwatch.observer/filing/0001193125-26-336841.json
- Plain text: https://secwatch.observer/filing/0001193125-26-336841.txt

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