---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-25-265705"
form_type: "8-K"
ticker: "UPB"
cik: "0002022626"
company_name: "Upstream Bio, Inc."
filed_at: "2025-11-05T23:59:59+00:00"
generated_at: "2026-05-17T00:26:01.877603+00:00"
event_type: "earnings"
sentiment: "positive"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# Upstream Bio Q3 loss $33.7M; VIBRANT Ph2 CRSwNP meets primary endpoint

## Summary
- VIBRANT Ph2 met primary endpoint: placebo-adjusted NPS reduction of -1.8 (p<0.0001) at 24 weeks.
- Key secondary endpoints met: 76% reduction in need for surgery/systemic corticosteroids (p=0.03).
- Cash $372.4M as of Sept 30, 2025; expected to fund operations through 2027.
- Net loss $33.7M vs $16.0M YoY; R&D expense rose to $33.0M from $15.4M on verekitug costs.
- VALIANT Ph2 severe asthma top-line due Q1 2026; VENTURE Ph2 COPD enrollment ongoing.

## SEC filing metadata
- accession: 0001193125-25-265705
- form_type: 8-K
- ticker: UPB
- cik: 0002022626
- company_name: Upstream Bio, Inc.
- filed_at: 2025-11-05T23:59:59+00:00
- event_type: earnings
- sentiment: positive
- materiality_score: 0.85
- calibrated_materiality_score: 0.85
- confidence: high
- sec_items: 2.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/2022626/000119312525265705/0001193125-25-265705-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/2022626/000119312525265705/upb-20251105.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-25-265705
- JSON: https://secwatch.observer/filing/0001193125-25-265705.json
- Plain text: https://secwatch.observer/filing/0001193125-25-265705.txt

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