---
schema_version: "secwatch.filing_event.v1"
accession: "0000950170-25-037619"
form_type: "8-K"
ticker: "UPB"
cik: "0002022626"
company_name: "Upstream Bio, Inc."
filed_at: "2025-03-12T23:59:59+00:00"
generated_at: "2026-05-24T22:49:33.657762+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.55
calibrated_materiality_score: 0.55
confidence: "high"
source: SEC EDGAR
---

# Upstream Bio posts Q4 net loss $21.2M; CRSwNP Ph2 enrollment complete; cash through 2027

## Summary
- Net loss of $21.2M in Q4 2024 ($11.8M in Q4 2023); R&D expenses $21.8M vs $11.6M.
- Completed enrollment in Phase 2 CRSwNP trial of verekitug; top-line data expected H2 2025.
- Cash, equivalents and investments $470.5M as of Dec 31, 2024, funded by upsized IPO ($293M gross).
- Phase 2 severe asthma data expected H2 2026; first COPD patient dosing on track for H2 2025.
- Appointed Daniella Beckman to Board and Allison Ambrose as General Counsel in late 2024.

## SEC filing metadata
- accession: 0000950170-25-037619
- form_type: 8-K
- ticker: UPB
- cik: 0002022626
- company_name: Upstream Bio, Inc.
- filed_at: 2025-03-12T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.55
- calibrated_materiality_score: 0.55
- confidence: high
- sec_items: 2.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/2022626/000095017025037619/0000950170-25-037619-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/2022626/000095017025037619/upb-20250312.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000950170-25-037619
- JSON: https://secwatch.observer/filing/0000950170-25-037619.json
- Plain text: https://secwatch.observer/filing/0000950170-25-037619.txt

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