WALTHAM, Mass. — February 11, 2026 — Leads & Copy — Upstream Bio, Inc. (Nasdaq: UPB) announced positive top-line results from its Phase 2 VALIANT clinical trial evaluating verekitug in adults with severe asthma.
The clinical-stage company is developing treatments for inflammatory diseases, initially focusing on severe respiratory disorders. Verekitug is the only known clinical-stage antagonist targeting the receptor for thymic stromal lymphopoietin (TSLP).
The VALIANT trial met its primary endpoint, showing a statistically significant and clinically meaningful reduction in the annualized asthma exacerbation rate (AAER) with both every 12 week (q12w) and every 24 week (q24w) dosing. Verekitug demonstrated a 56% reduction in AAER (p<0.0003) when dosed at 100 mg q12w and a 39% reduction (p<0.02) when dosed at 400 mg q24w, compared with placebo.
Lung function improvement, measured by forced expiratory volume in one second (FEV1), was 122 mL at week 60 with verekitug 100 mg q12w, and 139 mL at week 60 with 400 mg q24w, adjusted for placebo. At week 60, verekitug also suppressed exhaled nitric oxide (FeNO) compared to placebo by 20.4 ppb (p<0.0003) when dosed at 100 mg q12w, and by 26.3 ppb (p<0.0001) when dosed at 400 mg q24w. The data represented a mean 43.5% (p=0.03) reduction from baseline in the 100 mg q12w group and a mean 44.9% (p=0.03) reduction from baseline in the 400 mg q24w group. A third low-dose treatment group, 100 mg q24w, demonstrated a statistically significant effect on AAER, but did not provide consistent improvements in other endpoints.
Additional pre-specified analyses of secondary outcomes at week 24 showed statistically significant placebo-adjusted improvements compared to baseline in both FEV1 and FeNO with the 100 mg q12w and 400 mg q24w dose regimens.
Verekitug was generally well tolerated across all active doses, with a safety profile consistent with previous studies.
According to Aaron Deykin, MD, Chief Medical Officer and Head of Research & Development at Upstream Bio, the company is excited to share the data from VALIANT, which indicate the potential of verekitug’s meaningful clinical effect in severe asthma. He added that they will advance verekitug into Phase 3 clinical trials as quickly as possible.
Rand Sutherland, MD, Chief Executive Officer of Upstream Bio, stated that the findings strengthen verekitug’s potential to advance the standard of care with a competitive efficacy profile and less frequent dosing. He added that they intend to rapidly advance verekitug into Phase 3 trials in severe asthma and CRSwNP and continue to progress verekitug in the ongoing Phase 2 VENTURE trial in patients with COPD, where they have enrolled more than 60% of patients to date.
VALIANT (NCT06196879) is a Phase 2 global, randomized, double-blind, placebo-controlled, dose-ranging, parallel group clinical trial that evaluated the safety and efficacy of verekitug for up to 60 weeks, with a minimum of 24 weeks of treatment, in 478 patients with severe asthma.
Eligible participants who completed the Phase 2 VALIANT clinical trial were offered enrollment in VALOUR (NCT06966479), a long-term extension (LTE) study designed to evaluate the long-term safety and efficacy of verekitug. Current transition rates indicate more than 90% of eligible patients have rolled over to the Phase 2 VALOUR LTE study.
Upstream Bio designed the VALIANT trial using endpoints that, pending interactions with regulatory authorities, could produce data to support submissions for product approval. Planning activities for Phase 3 trials in severe asthma and CRSwNP have commenced, and the Company intends to initiate registrational trials in both indications following planned regulatory interactions.
Upstream Bio’s webcast to discuss the top-line results from the Phase 2 VALIANT trial will begin today at 8:00 a.m. ET. The live webcast can be accessed via this link or on the Events tab on the Investors section of the Company’s website.
Severe asthma is a complex, chronic inflammatory disease of the airways characterized by persistent symptoms, recurrent exacerbations, and impaired quality of life despite treatment with high-dose corticosteroids and other long-acting medication that accounts for a disproportionate share of asthma-related costs and healthcare utilization. Severe asthma is a heterogeneous disease driven by multiple inflammatory pathways, including both Type 2 and non-Type 2 mechanisms.
Verekitug is a novel recombinant fully human immunoglobulin G1 (IgG1) monoclonal antibody that binds to the thymic stromal lymphopoietin (TSLP) receptor and inhibits proinflammatory signaling initiated by TSLP. It is the only known antagonist currently in clinical development that targets and inhibits the TSLP receptor.
Upstream Bio is a clinical-stage biotechnology company developing treatments for inflammatory diseases, with an initial focus on severe respiratory disorders.
Source: Upstream Bio
