{"schema_version":"secwatch.filing_event.v1","accession":"0001193125-26-125057","form_type":"8-K","ticker":"UPB","cik":"0002022626","company_name":"Upstream Bio, Inc.","filed_at":"2026-03-26T23:59:59+00:00","discovered_at":"2026-05-14T18:02:37.016109+00:00","generated_at":"2026-05-15T08:54:46.380173+00:00","sec_items":["2.02","9.01"],"event_type":"other_material","sentiment":"positive","materiality_score":0.8,"calibrated_materiality_score":0.8,"confidence":"high","headline":"Upstream Bio details Phase 3 strategy for verekitug; positive Phase 2 asthma and CRSwNP data","bullets":["Phase 3 development plan for verekitug: high-dose quarterly regimen (up to 400 mg q12w) in severe asthma and CRSwNP; initiation in Q1 2027.","Phase 2 VALIANT asthma trial met primary endpoint: AAER reduction 56% (p<0.0003) with 100 mg q12w; safety profile favorable.","Phase 2 VIBRANT CRSwNP data: placebo-adjusted NPS reduction -1.95 (WOCF) and NCS reduction -0.96 at week 24.","Cash position $341.5M as of Dec 31, 2025, expected to fund operations through 2027.","Q4 2025 net loss $42.5M vs $21.2M a year ago; R&D expenses rose to $40.2M."],"urls":{"canonical":"https://secwatch.observer/filing/0001193125-26-125057","json":"https://secwatch.observer/filing/0001193125-26-125057.json","markdown":"https://secwatch.observer/filing/0001193125-26-125057.md","text":"https://secwatch.observer/filing/0001193125-26-125057.txt","edgar_index":"https://www.sec.gov/Archives/edgar/data/2022626/000119312526125057/0001193125-26-125057-index.htm","edgar_primary_document":"https://www.sec.gov/Archives/edgar/data/2022626/000119312526125057/upb-20260326.htm"},"model":{"generated_by":"deepseek-v4-flash:cloud@v2","generated_at":"2026-05-15T08:54:46.380173+00:00"},"review":{"review_status":"machine_generated","human_reviewed":false,"corrected":false,"correction_note":null,"correction_timestamp":null,"superseded_by":null,"related_filings":[]},"source_grounded_claims":[{"claim_id":"790ad456a317fdd57f30d3e97590f9b2399258f9","claim":"Upstream Bio, Inc. reported financial results for the quarter and year ended December 31, 2025.","evidence_excerpt":"On March 26, 2026, Upstream Bio, Inc. (the “Company”) announced its financial results and business highlights for the quarter and year ended December 31, 2025.","evidence_source":"SEC 8-K Item 2.02","evidence_url":"https://www.sec.gov/Archives/edgar/data/2022626/000119312526125057/0001193125-26-125057-index.htm","confidence":0.7,"family_label":"Earnings Releases","details":[{"label":"Period","value":"the quarter and year ended December 31, 2025"},{"label":"Result","value":"reported results"}],"fact_type":"earnings_release"}],"license":"Source filings: public domain (SEC EDGAR). Summaries (headline + bullets): CC-BY-4.0; attribute https://secwatch.observer"}