Upstream Bio verekitug met NPS target in 79% of VIBRANT patients

Upstream Bio has presented new responder analyses from its Phase 2 VIBRANT trial of verekitug in chronic rhinosinusitis with nasal polyps (CRSwNP), reporting that a large majority of treated participants achieved clinically meaningful improvements across the trial's primary and key secondary endpoints. The data were delivered in an oral session at the European Academy of Allergy and Clinical Immunology (EAACI) 2026 Congress in Istanbul on 14 June.

The headline finding was that 79% of verekitug-treated participants, roughly four in five, achieved a clinically meaningful improvement in nasal polyp score (NPS) at week 24, against 24% in the placebo group. The odds ratio of 12.06 (95% CI: 4.09–35.53; p less than 0.0001) was striking. The underlying placebo-adjusted NPS reduction of -1.95 points, reported previously, is nearly double the 1.0-point threshold generally considered clinically meaningful.

Key secondary endpoints

Secondary endpoint responder rates reinforced the primary finding. Some 83% of verekitug-treated participants achieved at least a four-point improvement in total symptom score, compared with 37% in the placebo group (OR 8.57; p less than 0.0001). Nasal congestion improved meaningfully in 72% of treated participants versus 39% on placebo (OR 3.99; p=0.0046), while 69% reported at least a one-point improvement in sense of smell against 21% on placebo (OR 8.52; p less than 0.0001). CT-measured sinus disease, assessed by Lund-Mackay score, showed meaningful improvement in 78% of treated participants compared with 12% on placebo. Verekitug was reported to be generally well tolerated, with no serious adverse events observed during the 24-week period.

Aaron Deykin, chief medical officer and head of research and development at Upstream Bio, said the analyses demonstrated "the depth and consistency of verekitug's clinical benefit" and pointed to the quarterly dosing schedule as a differentiating feature. The company plans to initiate Phase 3 registrational trials in both CRSwNP and severe asthma in the first quarter of 2027.

Market context and competitive positioning

Verekitug's mechanism is distinctive in this space. It targets the receptor for thymic stromal lymphopoietin (TSLP), a cytokine positioned upstream in the inflammatory cascade, rather than downstream mediators such as IL-4, IL-5 or IL-13. Upstream Bio describes it as the only known TSLP receptor antagonist currently in clinical development, differentiating it from approved biologic rivals including dupilumab (Sanofi/Regeneron, targeting IL-4Ralpha) and mepolizumab (GSK, targeting IL-5), which have established positions in the CRSwNP market.

The biologic therapy segment for severe upper and lower airway inflammatory disease is competitive and growing, with several agents now approved and multiple late-stage programmes in development. CRSwNP affects an estimated 4% of the general population, of whom roughly 40% have inadequately controlled disease, pointing to a meaningful residual unmet need even in markets with approved options. The strong association between CRSwNP and severe asthma, present in up to 70% of CRSwNP patients, also means verekitug's cross-indication strategy could be commercially efficient if Phase 3 data hold.

These analyses are post-hoc in design, which limits their interpretive weight compared with pre-specified endpoints. Regulators and investors will weigh the responder data as supportive evidence ahead of Phase 3 initiation, but the pivotal readout, anticipated no earlier than 2028 on a standard timeline, will be the definitive test of whether verekitug's efficacy profile translates into a competitive label.