Summary of RAPT Therapeutics Conference Call (October 20, 2025) Company Overview - **Company**: RAPT Therapeutics (NasdaqGM:RAPT) - **Focus**: Development of innovative therapies for chronic spontaneous urticaria (CSU) and other IgE-driven disorders Key Points from the Call Industry and Product Development - **Product**: RPT-nine zero four (also known as JYB-nineteen oh four) - **Indication**: Chronic spontaneous urticaria (CSU) - **Clinical Trial**: Phase II trial conducted in China, comparing RPT-nine zero four to omalizumab - **Results**: Top line data showed RPT-nine zero four demonstrated comparable efficacy to omalizumab with potential for superior durability and less frequent dosing [5][6][7][10][38] Efficacy and Safety Data - **Efficacy**: - RPT-nine zero four showed a 22.1 improvement in UAS7 at week twelve compared to 18.5 for omalizumab [21] - At week sixteen, RPT-nine zero four arms showed improvements of 23.2 and 22.2, while omalizumab showed 19.1 [21] - Complete response (UAS7=0) at week twelve was 37% and 39% for RPT-nine zero four compared to 24.4% for omalizumab [23] - **Safety**: - No serious adverse events or anaphylaxis reported [24] - Treatment emergent adverse events were similar across groups, indicating a favorable safety profile [24] Competitive Landscape - **Current Standard of Care**: Omalizumab, which requires monthly dosing and has limitations in durability and convenience [10][11] - **Market Research**: Survey of allergists indicated that the advantages of RPT-nine zero four would likely drive it to become the preferred treatment option for CSU patients [13] Future Development Plans - **Phase III Trials**: Plans to engage with regulatory authorities to discuss registrational pathways for RPT-nine zero four in CSU [8][39] - **Food Allergy Trials**: Anticipated initiation of Phase IIb trial for food allergies before the end of the year, with top line data expected in 2027 [39][40] - **Asthma Trials**: Smaller Phase II study in moderate to severe asthma expected to read out data by the end of the year [42] Market Potential - **Market Opportunity**: RPT-nine zero four is positioned to address unmet needs in CSU and food allergies, with a focus on less frequent dosing and broader efficacy in patients who are ineligible for omalizumab [39][40] Regulatory Considerations - **FDA Discussions**: Plans to discuss data with the FDA to align on Phase III study designs, with confidence in the translatability of data from Asian populations to Western populations [117] Expert Commentary - **Dr. Ana Maria Jimenez Arnaud**: Highlighted the unmet need for effective treatments in CSU and the potential of RPT-nine zero four to improve patient compliance due to less frequent dosing [28][32][34] Conclusion RAPT Therapeutics is advancing RPT-nine zero four as a promising treatment for CSU, demonstrating comparable efficacy to the current standard of care, omalizumab, with a favorable safety profile and potential for improved patient adherence through less frequent dosing. The company is preparing for Phase III trials and exploring additional indications, including food allergies and asthma.

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].