Upstream Bio, Inc. 8-K

What Happened

• On February 11, 2026, Upstream Bio filed an 8-K and issued a press release reporting positive top-line data from the Phase 2 VALIANT trial (NCT06196879) of verekitug in adults with severe asthma. The global, randomized, double-blind, placebo-controlled, dose-ranging trial enrolled 478 patients and evaluated up to 60 weeks of treatment (minimum 24 weeks).
• The trial met its primary endpoint (annualized asthma exacerbation rate, AAER). Verekitug reduced AAER by 56% (p<0.0003) at 100 mg every 12 weeks (q12w) and by 39% (p<0.02) at 400 mg every 24 weeks (q24w) versus placebo. Lung function (FEV1) improved by 122 mL (100 mg q12w) and 139 mL (400 mg q24w) at week 60 versus placebo. Exhaled nitric oxide (FeNO) was also significantly suppressed versus placebo for those doses.

Key Details

• Trial size and design: 478 adults, randomized, double-blind, placebo-controlled, up to 60 weeks (min 24 weeks).
• Primary endpoint: AAER reductions — 56% (p<0.0003) for 100 mg q12w; 39% (p<0.02) for 400 mg q24w.
• Secondary signals: Week 60 placebo-adjusted FEV1 improvements of 122 mL (100 mg q12w) and 139 mL (400 mg q24w); FeNO reductions of 20.4 ppb (p<0.0003) and 26.3 ppb (p<0.0001), respectively.
• Safety: Verekitug was generally well tolerated across active doses, consistent with prior studies. The 100 mg q24w dose showed AAER benefit but inconsistent secondary endpoint results.

Why It Matters

• These positive Phase 2 top-line results demonstrate efficacy on the trial’s primary endpoint (AAER) and measurable improvements in lung function and airway inflammation markers, which the company says could inform further clinical development and regulatory discussions for verekitug as a treatment for severe asthma.
• The filing also includes the company’s forward-looking statements and risk disclosures: advancing verekitug through development, obtaining regulatory approval, funding needs, third-party dependencies, and other risks could affect outcomes and timelines. Investors should view the results as promising Phase 2 data but note the company’s stated risks and that further clinical work and regulatory review are required.