THE SCIENCE TO OVERCOME INFLAMMATION Phase 2 Topline Results of RPT904 (JYB1904) in Chronic Spontaneous Urticaria OCTOBER 20, 2025 Disclaimer Statements in this Presentation that are not statements of historical fact are forward-looking statements. Such forward-looking statements include, without limitation, statements regarding the development of RPT904, including the expected timing of clinical trials and the availability of data therefrom; expectations regarding regulatory interactions; the therapeutic a ...

Summary of RAPT Therapeutics Conference Call Company Overview - RAPT Therapeutics focuses on inflammatory diseases, particularly in high-value indications that can disrupt standard care in multibillion-dollar markets [4][3] - The lead asset is RPT-904, a next-generation half-life extended anti-IgE antibody, differentiated from the first-generation molecule Xolair [4][5] Key Priorities and Developments - RAPT has partnered with GeminiCare for the development of RPT-904 in China, which is completing Phase 2 trials with data expected by year-end [5][6] - The company is particularly excited about the potential of RPT-904 in treating food allergies and chronic spontaneous urticaria (CSU) [5][6] Product Differentiation - RPT-904 has a half-life of 60 days compared to Xolair's 26 days, representing over a two-fold increase [12] - The molecule shows deeper and more sustained pharmacodynamic effects, particularly in reducing free IgE levels [12][9] - Improvements in affinity and reduced immunogenicity are also noted, with a fourfold increase in affinity compared to Xolair [8][11] Market Dynamics - The food allergy market is significant, with Xolair treating over 60,000 patients in its first year of launch [6][44] - RAPT estimates that 25-30% of food allergy patients are ineligible for Xolair treatment due to high IgE levels and body weight [22][21] - RPT-904 aims to address this ineligible population with less frequent dosing options (Q12 or Q8 weeks) [23][28] Clinical Trials and Regulatory Interaction - A Phase 2b food allergy study is planned to start before the end of the year, with favorable initial interactions with the FDA [24][27] - The trial design is based on the Outmatch study, aiming for a 100-patient enrollment with a focus on Xolair-naive patients [61][32] Competitive Landscape - The market for food allergies is large, with 17 million Americans diagnosed, and RPT-904 aims to differentiate itself through less burdensome dosing and addressing the ineligible patient population [50][52] - The company is aware of potential biosimilars for Xolair entering the market but believes RPT-904's unique attributes will allow for premium pricing [53][70] Future Opportunities - RAPT is also exploring indications beyond food allergies and CSU, including seasonal allergic rhinitis, which has a large patient population [89] - The company is developing next-generation oral molecules targeting Th2-driven disorders, indicating a broader pipeline strategy [99] Financial Position - RAPT reported a cash position of just under $170 million, expected to last through 2027, covering the timeline until the anticipated food allergy top-line readout [103] Conclusion - RAPT Therapeutics is strategically positioned in the inflammatory disease market with a focus on innovative treatments for food allergies and CSU, backed by promising clinical data and a solid financial runway [4][103]