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.