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 ...

Core Insights - RAPT Therapeutics and Shanghai Jeyou Pharmaceutical announced positive topline data from a Phase 2 trial of RPT904 for chronic spontaneous urticaria, showing comparable efficacy and safety to omalizumab [1][4][5] Study Design and Results - The Phase 2 study enrolled 137 adult patients with chronic spontaneous urticaria inadequately controlled by H1 antihistamines, randomized into three arms: RPT904 Q8W, RPT904 Q12W, and omalizumab Q4W [2] - The primary endpoint was the change in the seven-day urticaria activity score (UAS7) at Weeks 8, 12, and 16, with key secondary endpoints including the proportion of patients achieving UAS7=0 [2] - RPT904 demonstrated numerically greater improvements in UAS7 scores and a higher proportion of patients achieving UAS7=0 compared to omalizumab at all time points [3] Efficacy Data - Mean baseline UAS7 scores were similar across treatment arms, with RPT904 Q8W showing a least squares mean change from baseline of -20.51 at Week 8, -22.14 at Week 12, and -23.20 at Week 16 [3] - The proportion of patients with UAS7=0 at Week 16 was 45.65% for RPT904 Q8W and 43.48% for Q12W, compared to 33.33% for omalizumab [3] Safety Profile - RPT904 was well tolerated, with no serious adverse events related to the study drug and no treatment-related discontinuations [3][4] Future Development Plans - Jeyou plans to advance RPT904 to Phase 3 development in China, while RAPT will discuss the Phase 3 development path with the FDA [4][5] - RAPT also aims to initiate a Phase 2b trial in food allergies by the end of the year [5] Background Information - Chronic spontaneous urticaria is characterized by sudden onset hives and intense itch, with a need for therapies targeting the underlying IgE-autoantibody pathology [7] - RPT904 is a novel anti-IgE monoclonal antibody designed to provide extended pharmacokinetics compared to omalizumab, targeting the same epitope [8]

Core Insights - RAPT Therapeutics, Inc. plans to report topline data from the Phase 2 clinical trial of RPT904 in patients with Chronic Spontaneous Urticaria (CSU) on October 20, 2025 [1] - The clinical trial is conducted in partnership with Shanghai Jeyou Pharmaceutical Co., Ltd. [1] Company Overview - RAPT Therapeutics is a clinical-stage immunology-based biopharmaceutical company focused on discovering, developing, and commercializing novel therapies for inflammatory and immunological diseases [3] - The company utilizes proprietary expertise in immunology to develop therapies aimed at modulating critical immune responses underlying these diseases [3] Event Details - A webcast conference call will be hosted by RAPT on October 20, 2025, at 8:30 a.m. ET, which will include a slide presentation [2] - Participants can join the conference call via phone after pre-registering online [2]

Core Insights - RAPT Therapeutics, Inc. plans to report topline data from the Phase 2 clinical trial of RPT904 in patients with Chronic Spontaneous Urticaria (CSU) on October 20, 2025 [1] - The clinical trial is conducted in partnership with Shanghai Jeyou Pharmaceutical Co., Ltd. [1] Company Overview - RAPT Therapeutics is a clinical-stage immunology-based biopharmaceutical company focused on discovering, developing, and commercializing novel therapies for inflammatory and immunological diseases [3] - The company utilizes proprietary expertise in immunology to develop therapies aimed at modulating critical immune responses underlying these diseases [3] Event Details - A webcast conference call will be hosted by RAPT on October 20, 2025, at 8:30 a.m. ET, which will include a slide presentation [2] - Participants can join the conference call via phone after pre-registering online to receive a unique passcode [2]

Core Insights - RAPT Therapeutics has received FDA clearance for its IND application to initiate a Phase 2b clinical trial of RPT904 for food allergies, marking a significant advancement in the company's clinical development efforts [1][2] Company Overview - RAPT Therapeutics is a clinical-stage biopharmaceutical company focused on developing novel therapies for inflammatory and immunological diseases [5] Clinical Trial Details - The Phase 2b trial, named "prestIgE," will evaluate the safety and efficacy of RPT904 in patients with IgE-mediated food allergies, comparing two dosing regimens (every 8 weeks and every 12 weeks) against a placebo [3] - Approximately 100 participants with food allergies (peanut, milk, egg, walnut, or cashew) will be enrolled, with the primary endpoint being the proportion of participants achieving a target threshold in a double-blind, placebo-controlled oral food challenge at Week 24 [3] - The trial will consist of two parts, with participants receiving treatment for a total of 48 weeks, followed by a 16-week safety follow-up period [3] Product Information - RPT904 is a next-generation, half-life extended anti-IgE monoclonal antibody designed to inhibit free and cell-bound IgE, which is a key driver of allergic diseases [4] - The product aims to provide a differentiated therapeutic option compared to the first-generation anti-IgE monoclonal antibody, omalizumab [4]

Summary of RAPT Therapeutics Conference Call - September 15, 2025 Company Overview - RAPT Therapeutics focuses on discovering, developing, and commercializing therapeutics for inflammatory disorders, targeting multi-billion dollar markets [2][4] - The lead asset, RPT-904, is a next-generation anti-IgE antibody, in-licensed from Gemincare in China, aimed at improving upon omalizumab (Xolair) [2][6] - RPT-904 targets food allergies and chronic spontaneous urticaria, estimated at $40 billion and $5 billion markets respectively [2] Key Developments and Milestones - RPT-904 is currently in phase 2 trials, with multiple upcoming milestones [2] - The deal for RPT-904 included a $35 million upfront payment and potential milestones totaling $670 million, with worldwide rights excluding China [6][7] Market Opportunity - There are 17 million diagnosed food allergy patients in the U.S., with 3.5 million being children, indicating a significant unmet medical need [8] - Omalizumab was approved in February 2024, with over 60,000 patients already using it for food allergies, suggesting a $1 billion run rate [9] Competitive Landscape - RPT-904 is designed to have improved half-life and dosing convenience compared to omalizumab, with expectations of Q8 or Q12 week dosing [10][18] - The competitive landscape includes other IgE antibodies and novel approaches, but RAPT believes there is ample space for multiple entrants [12] Differentiation Factors - RPT-904's dosing regimen is expected to enhance patient compliance and reduce emergency room visits, which payers recognize as beneficial [15][16] - The drug aims to address high IgE, high weight patients who are currently excluded from the omalizumab label, presenting a unique market opportunity [17][19] Clinical Trials and Data - The phase IIB study is set to start before the end of the year, modeled after the OUTMATCH study for Xolair, focusing on food allergies [22] - Gemincare is conducting two phase 2 studies in China, with results expected to inform U.S. and European development [29] Financial Outlook - RAPT Therapeutics reported a cash balance of just under $170 million at the end of Q2, projected to last through the first half of 2027 [43] Future Considerations - The company is exploring the potential for a broader label that could include asthma and seasonal allergic rhinitis in the future [33] - RAPT is also developing a second-generation CCR4 antagonist, with plans to enter the clinic next year [40][41] Conclusion - RAPT Therapeutics is positioned to capitalize on significant market opportunities with RPT-904, leveraging its differentiated profile and upcoming clinical milestones to address unmet needs in the treatment of food allergies and chronic spontaneous urticaria [2][12][15]

Summary of RAPT Therapeutics FY Conference Call Company Overview - **Company**: RAPT Therapeutics (NasdaqGM:RAPT) - **Focus**: Transformative therapeutics for a range of IgE-mediated diseases, particularly food allergies and chronic spontaneous urticaria (CSU) [2][21] Pipeline and Product Development - **Lead Asset**: RPT-904, a next-generation anti-IgE antibody currently in phase 2 development [2] - **Comparison with Omalizumab**: RPT-904 preserves the Omalizumab epitope, which is critical for efficacy, unlike Ligalizumab, which failed to show superiority [5][9] - **Half-Life**: RPT-904 has a half-life of 60 days compared to Omalizumab's 26 days, allowing for less frequent dosing, which is expected to enhance patient compliance [10][12] Market Opportunity - **Food Allergy Market**: Approximately 17 million diagnosed patients in the U.S., with about 4 million being severe cases. RAPT aims for a 40-50% market share in this segment [33] - **Unmet Need**: 25-30% of food allergy patients are ineligible for Omalizumab, presenting a significant opportunity for RPT-904 [13][25] Clinical Trials - **Phase 2 Trials**: Two ongoing trials for RPT-904, one in CSU and one in asthma, with important data readouts expected [14][18] - **Trial Design**: The CSU trial involves a head-to-head comparison with Omalizumab, focusing on dosing frequency and efficacy [13][24] Differentiation Factors - **Dosing Regimen**: Less frequent dosing (Q8 or Q12 weeks) is expected to improve compliance and patient outcomes, particularly in food allergy [17][27] - **Efficacy in Omalizumab Ineligible Population**: RPT-904 aims to provide treatment options for patients excluded from Omalizumab trials, which is a significant differentiator [25][32] Financial Position - **Cash Position**: As of the end of Q2, RAPT had $170 million in cash, expected to last through the first half of 2027 [36] Upcoming Catalysts - **Data Readouts**: Anticipated results from phase 2b food allergy trial and partner trials in CSU and asthma by the end of the year [37] Conclusion - RAPT Therapeutics is strategically positioned in the IgE-mediated disease market with RPT-904, focusing on addressing unmet needs in food allergies and chronic spontaneous urticaria through innovative dosing and efficacy strategies [2][21][33]

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]

Financial Data and Key Metrics Changes - The company reported $170 million in cash at the end of Q2, which is expected to last through the second half of 2027, coinciding with the anticipated Phase IIb food allergy readout top-line data [73]. Business Line Data and Key Metrics Changes - RAPT Therapeutics is focused on RPT-904, a next-generation long-acting anti-IgE antibody, which is in Phase II development and targets food allergies and chronic spontaneous urticaria (CSU) [4][6]. - The food allergy market is valued at $40 billion in the United States, while CSU represents a $5 billion market [6]. Market Data and Key Metrics Changes - Xolair, a competitor drug, has approximately 60,000 patients in the food allergy indication and is growing rapidly, indicating a significant unmet medical need in this area [10][11]. - There are about 17 million food allergy patients in the United States, comparable to the number of atopic dermatitis patients [11]. Company Strategy and Development Direction - The company aims to differentiate RPT-904 from Xolair by offering similar efficacy with less frequent dosing (Q8 or Q12 weeks compared to Xolair's Q2 or Q4 weeks) [34][35]. - RAPT Therapeutics plans to initiate a Phase 2b study for food allergies before the end of the year, following a design similar to the OUTMATCH study that led to Xolair's approval [60][65]. Management's Comments on Operating Environment and Future Outlook - Management expressed confidence in the potential of RPT-904 to meet the needs of patients currently ineligible for Xolair therapy, filling a significant gap in treatment options [33]. - The company is optimistic about the upcoming data from GeminCare's studies, which could accelerate their timeline to market for CSU [40][46]. Other Important Information - The patent for omalizumab (Xolair) is set to expire later this year, leading to expectations of price erosion for the branded product [15][16]. - RAPT Therapeutics is collaborating with GeminCare, a multibillion-dollar Chinese pharmaceutical company, to support the development of RPT-904 [38]. Q&A Session Summary Question: What is the expected market presence for ZOLIER biosimilars? - The patent on omalizumab expires later this year, with biosimilars expected to enter the market in the latter part of next year, leading to anticipated price erosion of branded Omalizumab [15][16]. Question: What is the strategy for positioning RPT-904 against ZOLIER biosimilars? - The company aims for omalizumab-like efficacy and safety with dosing every eight weeks as the base case, and every twelve weeks as the upside case [34][35]. Question: What does success look like for the CSU readout? - Success is defined as achieving omalizumab-like efficacy at Q8 week dosing, with the potential for Q12 week dosing to command a premium price [52]. Question: What is the rationale for conducting a PKPD study? - The PKPD study aims to confirm that the pharmacokinetics and pharmacodynamics observed in healthy volunteers will extrapolate to patients with higher IgE levels [42]. Question: What is the expected timeline for the Phase IIb food allergy study? - The Phase IIb study is on track to start before the end of the year, with initial interactions with the FDA having gone well [65].

Core Insights - RAPT Therapeutics, Inc. is a clinical-stage biopharmaceutical company focused on developing therapies for inflammatory and immunological diseases [2] Group 1: Company Overview - RAPT Therapeutics specializes in discovering, developing, and commercializing novel therapies aimed at modulating immune responses related to inflammatory and immunological diseases [2] - The company leverages proprietary expertise in immunology to create innovative treatment options for patients [2] Group 2: Upcoming Events - RAPT management will participate in several investor conferences in September 2025, including: - 2025 Wells Fargo Healthcare Conference on September 3, 2025, at 12:45 p.m. ET [3] - Cantor Global Healthcare Conference on September 4, 2025, at 1:00 p.m. ET [3] - H.C. Wainwright 27th Annual Global Investment Conference on September 9, 2025, at 9:00 a.m. ET [3] - Stifel 2025 Virtual Immunology & Inflammation Forum on September 15, 2025, at 9:30 a.m. ET [3] - Live webcasts and archived recordings of these events will be available on the RAPT Therapeutics website [1]