{"schema_version":"secwatch.filing_event.v1","accession":"0001193125-26-045500","form_type":"8-K","ticker":"UPB","cik":"0002022626","company_name":"Upstream Bio, Inc.","filed_at":"2026-02-11T23:59:59+00:00","discovered_at":"2026-05-14T18:02:37.015620+00:00","generated_at":"2026-05-16T03:24:21.361747+00:00","sec_items":["7.01","8.01","9.01"],"event_type":"other_material","sentiment":"positive","materiality_score":0.8,"calibrated_materiality_score":0.8,"confidence":"high","headline":"Upstream Bio reports positive Phase 2 VALIANT results: verekitug reduces asthma exacerbations by 56% and 39%","bullets":["Verekitug 100 mg q12w reduced AAER by 56% (p<0.0003); 400 mg q24w reduced AAER by 39% (p<0.02) vs placebo.","Placebo-adjusted FEV1 improvement of 122 mL (q12w) and 139 mL (q24w) at week 60.","FeNO suppressed vs placebo by 20.4 ppb (q12w) and 26.3 ppb (q24w); mean reductions of 43-45% from baseline.","Verekitug well tolerated with safety consistent with prior studies; >90% of eligible patients rolled over to VALOUR LTE.","Company plans to advance verekitug into Phase 3 trials in severe asthma and CRSwNP after regulatory interactions."],"urls":{"canonical":"https://secwatch.observer/filing/0001193125-26-045500","json":"https://secwatch.observer/filing/0001193125-26-045500.json","markdown":"https://secwatch.observer/filing/0001193125-26-045500.md","text":"https://secwatch.observer/filing/0001193125-26-045500.txt","edgar_index":"https://www.sec.gov/Archives/edgar/data/2022626/000119312526045500/0001193125-26-045500-index.htm","edgar_primary_document":"https://www.sec.gov/Archives/edgar/data/2022626/000119312526045500/d44802d8k.htm"},"model":{"generated_by":"deepseek-v4-flash:cloud@v2","generated_at":"2026-05-16T03:24:21.361747+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":[],"license":"Source filings: public domain (SEC EDGAR). Summaries (headline + bullets): CC-BY-4.0; attribute https://secwatch.observer"}