Translational Data Illustrate a Mechanism of Greater Potency with Verekitug, a Novel Antibody Antagonist of the TSLP Receptor

– Pharmacology modeling data presented at the European Academy of Allergy & Clinical Immunology (EAACI) Congress describe mechanistic insights for greater potency with verekitug compared to tezepelumab –

– Supports potentially differentiated profile of verekitug across a broad range of inflammatory diseases, including severe asthma, chronic obstructive pulmonary disease (COPD) and chronic rhinosinusitis with nasal polyps (CRSwNP) –

WALTHAM, Mass., June 15, 2025 (GLOBE NEWSWIRE) -- Upstream Bio, Inc. (Nasdaq: UPB), a clinical-stage company developing treatments for inflammatory diseases, with an initial focus on severe respiratory disorders, today announced the presentation of translational pharmacology modeling data supporting verekitug’s Thymic Stromal Lymphopoietin (TSLP) receptor targeting as a mechanism for greater potency when compared to treatments targeting the TSLP ligand. Data were presented at the European Academy of Allergy & Clinical Immunology (EAACI) Congress taking place June 13-16, 2025, in Glasgow, United Kingdom.

TSLP is a cytokine that is a key driver of the inflammatory response in major allergic and inflammatory diseases, such as asthma, where disruption of TSLP signaling has been clinically validated as an effective treatment approach. Because TSLP is a target upstream in the inflammatory cascade, blocking the TSLP receptor presents an opportunity for a single treatment to impact the drivers of multiple pathological inflammatory processes across a broad set of diseases. Upstream is developing verekitug in multiple severe respiratory diseases including severe asthma, COPD, and CRSwNP. Verekitug is the only monoclonal antibody currently in clinical development that targets and inhibits the TSLP receptor.

“These data reinforce our belief in the differentiated profile of verekitug, as the model elucidates important biologic parameters that drive the differentiated rapid, substantial and sustained treatment effects observed through TSLP receptor inhibition with verekitug,” said Aaron Deykin, MD, Chief Medical Officer and Head of Research & Development of Upstream Bio. “We look forward to further assessing the potential translation of this unique mechanism into clinical benefit in patients with severe respiratory diseases, first with top-line Phase 2 clinical data in CRSwNP in the third quarter of this year followed by data in severe asthma in the first half of 2026.”