Upstream Bio (UPB) investor relations material

Vision and strategy

• Focused on developing verekitug, a potent monoclonal antibody antagonist of the TSLP receptor, for severe asthma and other indications.

• Emphasizes delivering outstanding efficacy with less frequent, quarterly dosing, differentiating from competitors.

• Aims to de-risk the program through robust phase II data and informed dose selection for phase III.

• Plans to align with regulators and communicate a clear path forward by Q3 this year.

Clinical trial results and development plans

• Phase II VALIANT trial in severe asthma showed statistically significant 56% reduction in exacerbations at high dose (100 mg Q12 weeks).

• Efficacy and biomarker improvements were consistent with or exceeded marketed products, especially at quarterly dosing.

• Dose ordering observed, with efficacy diminishing at lower doses, supporting quarterly dosing as optimal.

• Over 90% of phase II patients rolled over into the long-term extension study, providing extended safety and efficacy data.

Competitive landscape and market positioning

• Only TSLP receptor-targeting drug in development, while competitors target the ligand or use Fc engineering.

• Differentiation focuses on efficacy, dosing convenience, and robust safety data to appeal to regulators, physicians, and patients.

• Market is converging around a few key targets (TSLP, IL-4, IL-13, IL-5, IgE), with quarterly dosing seen as highly valuable.

• Success depends on meaningful differentiation in efficacy and convenience over products like Tezspire and Dupixent.