Upstream Bio Presents Pharmacology Modeling Data Supporting Verekitug's Potency over Tezepelumab at EAACI Congress

Upstream Bio presented data at the EAACI Congress indicating that its drug candidate, verekitug, which targets the TSLP receptor, demonstrates greater potency than tezepelumab (which targets the TSLP ligand) in preclinical models. Pharmacology modeling suggests verekitug achieves complete and sustained inhibition of the TSLP/TSLPR complex, potentially leading to a greater reduction in lung inflammation across inflammatory diseases like severe asthma and COPD. Verekitug is currently in Phase 2 trials for severe asthma and CRSwNP, with COPD trials planned, though the company notes that clinical trial outcomes are not yet guaranteed.

Analysis

Upstream Bio (Nasdaq: UPB) has presented translational pharmacology modeling data at the European Academy of Allergy & Clinical Immunology Congress suggesting its investigational antibody, verekitug, which targets the TSLP receptor, exhibits greater potency than tezepelumab, an existing therapy targeting the TSLP ligand. The *in silico* modeling indicates verekitug could achieve complete and sustained inhibition of the TSLP/TSLPR complex, potentially resulting in a more substantial reduction in lung inflammation, as measured by fractional exhaled nitric oxide (FeNO), across conditions such as severe asthma, COPD, and chronic rhinosinusitis with nasal polyps (CRSwNP). This potential for enhanced potency is attributed to targeting the TSLP receptor, which reportedly has lower expression levels and slower protein turnover compared to the TSLP ligand. While these preclinical findings, presented at a prestigious congress, bolster Upstream Bio's scientific credibility and suggest a differentiated therapeutic profile for verekitug, it is crucial to note that these are based on modeling and are subject to clinical validation, with the company highlighting significant risks in trial progression and regulatory approval. Verekitug is advancing through Phase 2 clinical trials for severe asthma and CRSwNP, with key data readouts anticipated for CRSwNP in Q3 2025 and for severe asthma in H1 2026, and trials for COPD are also planned.

Key Decisions for Investors

• Closely monitor upcoming Phase 2 clinical trial readouts for verekitug in CRSwNP (Q3 2025) and severe asthma (H1 2026) as key catalysts for validating preclinical potency claims.
• Recognize the speculative nature of Upstream Bio at this stage, as verekitug's differentiation currently relies on *in silico* modeling, pending robust clinical efficacy and safety data.
• Evaluate the risk-reward profile by balancing the potential for a novel, potent treatment in significant inflammatory disease markets against the substantial clinical development and regulatory risks inherent to early-stage biotechnology companies.