# EDGAR Filing Document

**Accession Number:** 0001673772
**File Stem:** 0001193125-25-243053
**Filing Date:** 2025-10
**Character Count:** 25299
**Document Hash:** 47add26317ce33dcbbab42b3ee4934b8
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-25-243053.hdr.sgml**: 20251020

**ACCESSION NUMBER**: 0001193125-25-243053

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 29

**CONFORMED PERIOD OF REPORT**: 20251020

**ITEM INFORMATION**: Regulation FD Disclosure

**ITEM INFORMATION**: Other Events

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20251020

**DATE AS OF CHANGE**: 20251020

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** RAPT Therapeutics, Inc.
- **CENTRAL INDEX KEY:** 0001673772
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 473313701
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-38997
- **FILM NUMBER:** 251402357

**BUSINESS ADDRESS:**
- **STREET 1:** 561 ECCLES AVENUE
- **CITY:** SOUTH SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94080
- **BUSINESS PHONE:** (650) 489-9000

**MAIL ADDRESS:**
- **STREET 1:** 561 ECCLES AVENUE
- **CITY:** SOUTH SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94080

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** FLX Bio, Inc.
- **DATE OF NAME CHANGE:** 20160504

?xml version='1.0' encoding='ASCII'? 8-K

**UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549**

------

## FORM 8-K

------

**CURRENT REPORT**

**Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934**

**Date of Report (Date of earliest event reported):** October 20, 2025<br>

------

RAPT Therapeutics, Inc.

**(Exact name of Registrant as Specified in Its Charter)**

------

---

| | | |
|:---|:---|:---|
| Delaware | 001-38997 | 47-3313701 |
| **(State or Other Jurisdiction<br>of Incorporation)** | **(Commission File Number)** | **(IRS Employer<br>Identification No.)** |
| 561 Eccles Avenue |  |  |
| South San Francisco**,** California |  | 94080 |
| **(Address of Principal Executive Offices)** |  | **(Zip Code)** |

---

**Registrant's Telephone Number, Including Area Code:** (650) 489-9000<br>

N/A<br>

**(Former Name or Former Address, if Changed Since Last Report)**

------

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

**Securities registered pursuant to Section 12(b) of the Act:**

---

| | | |
|:---|:---|:---|
| **<br>Title of each class** | **Trading<br>Symbol(s)** | **<br>Name of each exchange on which registered** |
| Common Stock, $0.0001 par value per share | RAPT | The Nasdaq Stock Market LLC |

---

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

------

## Item 7.01 Regulation FD Disclosure.
RAPT Therapeutics, Inc. (the "Company") is furnishing the investor presentation slides (the "Corporate Presentation") attached hereto as Exhibit 99.1, which the Company may use from time to time in conversations with investors and analysts.

The information furnished under this Item 7.01, including Exhibit 99.1, shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or subject to the liabilities of that section. The information shall not be deemed incorporated by reference into any other filing with the Securities and Exchange Commission made by the Company, regardless of any general incorporation language in such filing.

**Item 8.01 Other Events.**

On October 20, 2025, the Company and Shanghai Jeyou Pharmaceutical Co., Ltd. ("Jeyou," formerly called Shanghai Jemincare Pharmaceutical Co., Ltd.), a leading pharmaceutical company in China, announced positive topline data from Jeyou's phase 2 trial of RPT904 (JYB1904) (the "Phase 2 Trial") as monotherapy in chronic spontaneous urticaria ("CSU"). The Phase 2 Trial, which was conducted in China, was designed to evaluate the safety and efficacy of RPT904 at dosing intervals of 8 weeks ("Q8W") and 12 weeks ("Q12W") compared to omalizumab dosed every 4 weeks ("Q4W"). The Phase 2 Trial was not a formal non-inferiority study and no statistical hypothesis was tested. The data from the Phase 2 Trial indicate that RPT904 dosed Q8W or Q12W has comparable efficacy and safety to omalizumab dosed Q4W. The Company and Jeyou believe these results warrant advancing RPT904 to phase 3 development, and the Company plans to discuss next steps regarding development of RPT904 for CSU with the U.S. Food and Drug Administration and other regulatory authorities.

The randomized, double-blind Phase 2 Trial enrolled 137 adult patients with CSU inadequately controlled by H1 antihistamines for a 16-week treatment period with patients randomized 1:1:1 across three arms. Patients randomized to the RPT904 Q8W arm received 300 mg subcutaneously ("SC") at Week 0 and Week 8, while patients randomized to the RPT904 Q12W arm received a single 300 mg SC dose at Week 0 (to represent a dosing interval of at least every 12 weeks). Patients randomized to the omalizumab Q4W arm received 300 mg SC at Weeks 0, 4, 8 and 12. The primary endpoint was change from baseline in the seven-day urticaria activity score ("UAS7") at Weeks 8, 12 and 16, and a key secondary endpoint was the proportion of patients with UAS7=0 at Weeks 8, 12 and 16. After the initial 16-week treatment period, patients were followed for an additional 16 weeks without additional treatment. The topline data reported herein are from the initial 16-week treatment period.

The data from both the RPT904 Q8W and Q12W treatment arms showed numerically greater improvement on the UAS7 endpoint and numerically higher proportion of patients with UAS7=0 at all timepoints (Weeks 8, 12 and 16) compared to omalizumab Q4W.

The mean baseline UAS7 scores (±SD) in the RPT904 Q8W, Q12W and omalizumab Q4W arms were 28.7 (±7.2), 28.9 (±6.6) and 28.8 (±7.9), respectively. The least squares mean change from baseline in UAS7 (and 95% confidence interval) at the three time points were:

---

| | | | |
|:---|:---|:---|:---|
|  | &nbsp;&nbsp;RPT904<br>Q8W (N=46) | &nbsp;&nbsp;RPT904<br>Q12W (N=46) | &nbsp;&nbsp;omalizumab<br>Q4W (N=45) |
| &nbsp;&nbsp;Week 8 | &nbsp;&nbsp;-20.51 (-23.88, -17.13) | &nbsp;&nbsp;-21.05 (-24.42, -17.67) | &nbsp;&nbsp;-17.00 (-20.39, -13.61) |
| &nbsp;&nbsp;Week 12 | &nbsp;&nbsp;-22.14 (-25.46, -18.82) | &nbsp;&nbsp;-21.73 (-25.04, -18.43) | &nbsp;&nbsp;-18.51 (-21.83, -15.18) |
| &nbsp;&nbsp;Week 16 | &nbsp;&nbsp;-23.20 (-26.49, -19.91) | &nbsp;&nbsp;-22.16 (-25.43, -18.89) | &nbsp;&nbsp;-19.14 (-22.43, -15.86) |

---

The proportion of patients (as a percentage) with UAS7=0 (and 95% confidence interval) at the three time points were:

---

| | | | |
|:---|:---|:---|:---|
|  | &nbsp;&nbsp;RPT904<br>Q8W (N=46) | &nbsp;&nbsp;RPT904<br>Q12W (N=46) | &nbsp;&nbsp;omalizumab<br>Q4W (N=45) |
| &nbsp;&nbsp;Week 8 | &nbsp;&nbsp;32.61 (19.53, 48.02) | &nbsp;&nbsp;32.61 (19.53, 48.02) | &nbsp;&nbsp;31.11 (18.17, 46.65) |
| &nbsp;&nbsp;Week 12 | &nbsp;&nbsp;36.96 (23.21, 52.45) | &nbsp;&nbsp;39.13 (25.09, 54.63) | &nbsp;&nbsp;24.44 (12.88, 39.54) |
| &nbsp;&nbsp;Week 16 | &nbsp;&nbsp;45.65 (30.90, 60.99) | &nbsp;&nbsp;43.48 (28.93, 58.89) | &nbsp;&nbsp;33.33 (20.00, 48.95) |

---

In the Phase 2 Trial, RPT904 was well tolerated with no serious adverse events related to study drug and no treatment-related adverse events resulting in treatment discontinuation.

In addition, the Company anticipates initiating a phase 2b clinical trial of RPT904 in food allergies before the end of 2025.

------

**Forward Looking Statements**

This Current Report on Form 8-K (including the exhibit thereto) contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as "anticipate," "estimates," "expects," "look forward," "planned," "potential" "will" and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements. These statements relate to future events and involve known and unknown risks, uncertainties and other factors that may cause actual results, performance or achievements to be materially different from any future performances or achievements expressed or implied by the forward-looking statements. Each of these statements is based only on current information, assumptions and expectations that are inherently subject to change and involve a number of risks and uncertainties. Forward-looking statements include, but are not limited to, statements about the efficacy and safety profile of RPT904, the clinical development of RPT904, including timing of clinical trials and expectations of the Company and Jeyou to advance RPT904 to phase 3, plans for regulatory interactions, the therapeutic and commercial potential of RPT904, and other statements that are not historical fact. Many factors may cause differences between current expectations and actual results, including unexpected or unfavorable safety or efficacy data observed during clinical studies, preliminary data and trends that may not be predictive of future data or results or that may not demonstrate safety or efficacy or lead to regulatory approval, the Company's reliance on its partners and other third parties, clinical trial site activation or enrollment rates that are lower than expected, unanticipated or greater than anticipated impacts or delays due to macroeconomic and geopolitical conditions (including the long-term impacts of ongoing overseas conflicts, tariffs and trade tensions, fluctuations in inflation and interest rates and other economic uncertainty), changes in expected or existing competition, changes in the regulatory environment, the uncertainties and timing of the regulatory approval process and the sufficiency of the Company's cash resources. Detailed information regarding risk factors that may cause actual results to differ materially from the results expressed or implied by statements in this press release may be found in the Company's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (SEC) on August 7, 2025 and subsequent filings made by the Company with the SEC. These forward-looking statements speak only as of the date hereof. The Company disclaims any obligation to update these forward-looking statements, except as required by law.

**Item 9.01 Financial Statements and Exhibits.**

---

| | |
|:---|:---|
| &nbsp;&nbsp;**Exhibit No.** | &nbsp;&nbsp;**Description** |
| &nbsp;&nbsp;99.1 | &nbsp;&nbsp;[<u>Corporate Presentation</u>](rapt-ex99_1.htm) |
| &nbsp;&nbsp;104 | &nbsp;&nbsp;Cover Page Interactive Data File (embedded within the Inline XBRL document). |

---

------

**SIGNATURES**

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

---

| | | | |
|:---|:---|:---|:---|
|  |  |  | **RAPT Therapeutics, Inc.** |
| Date: | October 20, 2025 | By:  | /s/ Rodney Young |
|  |  |  | Rodney Young<br>Chief Financial Officer |

---

------

## Exhibit 99.1

![Slide 1](rapt-ex99_1s1.jpg)

THE SCIENCE TOOVERCOME INFLAMMATION OCTOBER 20, 2025 Phase 2 Topline Results of RPT904 (JYB1904) in Chronic Spontaneous Urticaria

------

![Slide 2](rapt-ex99_1s2.jpg)

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 and commercial potential of RPT904, including as compared to omalizumab; and the ability to obtain necessary regulatory approvals. Words such as "believe," "anticipate," "plan," "expect," "will," "may," "could," "upcoming," "projected," "milestone," "potential," "target" or the negative of these terms or similar expressions are intended to identify forward-looking statements, though not all forward-looking statements necessarily contain these identifying words. These forward-looking statements are based on the current beliefs of the Company's management with respect to future events and trends and are subject to known and unknown risks and uncertainties that may cause our actual performance or achievements to be materially different from any future performance or achievements expressed or implied by the forward-looking statements in this Presentation. Risks and uncertainties that may cause actual results to differ materially include: risks inherent in the initiation, progress and completion of clinical trials and clinical development of our product candidates; the risk that clinical trials may have unsatisfactory outcomes; risks associated with preclinical development of product candidates; regulatory authorities, including the U.S. Food and Drug Administration (FDA) may not agree with our interpretation of the data from clinical trials of our drug candidates; we may decide, or regulatory authorities may require us, to conduct additional clinical trials or to modify our ongoing clinical trials; we may experience delays in the commencement, enrollment, completion or analysis of clinical testing for our drug candidates, or significant issues regarding the adequacy of our clinical trial designs or the execution of our clinical trials may arise, which could result in increased costs and delays, or limit our ability to obtain regulatory approval; our drug candidates may not receive regulatory approval or be successfully commercialized; unexpected adverse side effects or inadequate therapeutic efficacy of our drug candidates could delay or prevent regulatory approval or commercialization; uncertainties inherent in the conduct of clinical trials, reliance on our partners and third parties over which we may not always have full control; our ability to enter into strategic partnerships on commercially reasonable terms; our ability to obtain additional financing; the uncertainty regarding the macroeconomic environment and other risks and uncertainties that are described in the "Risk Factors" section of our most recent Form 10-Q filed with the Securities and Exchange Commission, and any current and periodic reports filed thereafter. These forward-looking statements should not be taken as forecasts or promises nor should they be taken as implying any indication, assurance or guarantee that any assumptions on which such forward-looking statements have been made are correct or exhaustive or, in the case of such assumptions, fully stated in the Presentation. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date this Presentation is given. Although we believe that the beliefs and assumptions reflected in the forward-looking statements are reasonable, we cannot guarantee future performance or achievements. Except as required by law, we undertake no obligation to update publicly any forward-looking statements for any reason after the date of this Presentation. This Presentation discusses drug candidates that are under clinical study and which have not yet been approved for marketing by the U.S. FDA. No representation is made as to the safety or effectiveness of any drug candidates for any use for which such drug candidates are being studied.

------

![Slide 3](rapt-ex99_1s3.jpg)

Summary of RPT904 Phase 2 Results in CSU RPT904 at both Q8W and Q12W dosing showed comparable efficacy and safety to omalizumab at Q4W dosing Both RPT904 arms showed numerically superior efficacy to omalizumab arm on UAS7 and UAS7=0 (complete response) across all timepoints\* Sustained efficacy out to 16 weeks after a single 300 mg dose underscores durability RPT904 was well tolerated with no drug related SAEs or discontinuations and no AEs of special interest (i.e. anaphylaxis) We believe results support moving to pivotal Phase 3 studies in CSU Jeyou and RAPT to approach regulatory agencies in respective territories to discuss potential registrational paths to approval Additional efficacy and safety data from this trial be presented at future medical conferences \*Study was not a formal non-inferiority study; no statistical hypothesis was tested

------

![Slide 4](rapt-ex99_1s4.jpg)

SENSITIZATION PHASE EFFECTOR PHASE IgE is Key Driver of Allergic Reactions Allergen is first introduced – Immune response is initiated Captures allergen, presents it to T cells Promotes B cell development Produces IgEantibodies Th2 Cell B Cell/ Plasma Cell APC ALLERGIC REACTION Food Allergy Chronic Urticaria Asthma Chronic Rhinosinusitis FceR1 Re exposure to allergen–Immediate allergic reaction Mast Cell Basophil IgE Blocks IgE binding to its receptor Removes IgE from cell surface RPT904

------

![Slide 5](rapt-ex99_1s5.jpg)

Omalizumab is Highly Effective in Chronic Spontaneous Urticaria and is Standard of Care Results not from head-to-head trials; no direct comparisons can be made. Omalizumab 300 mg Q4W REMIBRUTINIB 25 mg BID DUPILUMAB 300 mg Q2W -11.3 -5.0 -6.3 -7.9 -6.8 -13.4 -12.6 REMIX-1 REMIX-2 RILZABRUTINIB 400 mg TID BARZOLVOLIMAB 300 mg Q8W 150 mg Q4W ASTERIA II CUPID A RILESCU PHASE 2 UAS7 Placebo-Adjusted Change From Baseline at Week 12

------

![Slide 6](rapt-ex99_1s6.jpg)

RPT904 is a Next Generation anti-IgE Antibody Bio-Better with Several Potential Advantages over Omalizumab \* RAPT primary research CSU demand study of n=50 allergists Longer half-life Higher potency Improved drug-like properties Same epitope Strong IP RPT904 OMA RPT904 Potential Advantages Over Omalizumab for CSU Greater durability and more convenient dosing: Q8W or 12W vs. Q4W Greater compliance leading to improved clinical outcomes Reduced requirement for "updosing" Market research suggests these advantages would support RPT904 as the preferred treatment option\*

------

![Slide 7](rapt-ex99_1s7.jpg)

CSU Phase 2 Trial Design (Jeyou) Primary Endpoint: Change from baseline in UAS7 at Week 8, 12, 16 Secondary: UAS7=0, ISS7, HSS7, AAS7, DLQI at Week 8, 12, 16 N=135 (1:1:1), 45 per arm China sites 16-Week Follow Up RPT904 300 mg Q12W (N=45) RPT904 300 mg Q8W (N=45) Omalizumab 300 mg Q4W (N=45) Randomization (1:1:1) 0 WEEKS 16 4 8 12 32 Topline Data RPT904 Placebo omalizumab Screening Treatment Adults with CSU inadequately controlled by H1 antihistamines Randomized Double-Blind Active-Control Study of RPT904 Monotherapy

------

![Slide 8](rapt-ex99_1s8.jpg)

Subject Disposition 187 Screened Omalizumab Q4W N=45 Completed Week 16 43 (95.6%) N=137 Randomized RPT904 Q8W N=46 3 (6.5%) discontinued 1 Withdrawal of Consent 1 Non-compliance 1 Personal Reason 2 (4.4%) discontinued 0 Withdrawal of Consent 1 Non-compliance 1 Insufficient Efficacy Completed Week 16 43 (93.5%) RPT904 Q12W N=46 1 (2.2%) discontinued 0 Withdrawal of Consent 0 Non-compliance 1 Insufficient Efficacy Completed Week 16 45 (97.8%) 26.7% Screen Failure Rate

------

![Slide 9](rapt-ex99_1s9.jpg)

Key Demographics and Baseline Characteristics \* Discontinuation of omalizumab for non-efficacy reasons only. Minimum 4-month washout period (prior to Screening) Characteristics RPT904 Q8W (N = 46) RPT904 Q12W (N = 46) Omalizumab (N = 45) Age (years) – Mean (SD) 41.5 (13.3) 40.2 (13.6) 38.0 (12.8) Female, n (%) 26 (56.5) 35 (76.1) 28 (62.2) Weight (kg) - Mean (SD) 68.4 (14.6) 66.0 (13.3) 64.1 (12.7) CSU duration of illness (months) - Mean (SD) 34.3 (57.1) 23.3 (34.1) 22.5 (27.4) UAS7 - Mean (SD) 28.7 (7.2) 28.9 (6.6) 28.8 (7.9) ISS7 - Mean (SD) 13.9 (3.5) 14.1 (3.3) 14.5 (3.8) ISS7≤ 8 Subjects, n (%) 4 (8.7) 1 (2.2) 0 (0) HSS7 - Mean (SD) 14.7 (4.3) 14.7 (3.7) 14.4 (4.6) AAS7 - Mean (SD) 27.8 (32.8) 20.0 (33.8) 25.5 (33.1) DLQI - Mean (SD) 16.2 (6.7) 16.5 (6.77) 15.6 (6.8) Subjects previously receiving omalizumab\*, n (%) 5 (10.9) 5 (10.9) 6 (13.3)

------

![Slide 10](rapt-ex99_1s10.jpg)

Primary Endpoint: Change from Baseline in UAS7 \* Estimated based on the MMRM model, using the change from baseline in UAS7 values as the dependent variable, the baseline UAS7 score as the covariate, and randomization stratification factors (prior use of omalizumab or other biologic agents used for CSU), group, visit, and the interaction between group and visit as fixed effects. LS Mean Change in UAS7 Weeks UAS7 Mean Change from Baseline

------

![Slide 11](rapt-ex99_1s11.jpg)

Secondary Endpoint (Itch and Hive Severity Score) \* LS mean was estimated by the MMRM model: the model had baseline score as a covariate, with randomization-stratified factors (prior use of omalizumab or other biologics used in CSU), group, visit, and the interaction between group and visit as fixed effects. ISS7 Mean Change from Baseline HSS7 Mean Change from Baseline Weeks Weeks LS Mean Change in HSS7 LS Mean Change in ISS7

------

![Slide 12](rapt-ex99_1s12.jpg)

Secondary Endpoint: Proportion of Subjects with UAS7=0 ("Complete Response") \* Proportion of UAS7=0 subjects using LOCF-filled outcomes with CMH chi-square test for stratification (prior use of omalizumab or other biologics used in CSU). % Subjects with UAS7=0 Weeks

------

![Slide 13](rapt-ex99_1s13.jpg)

Safety Summary † AESI: Grade 5 allergic reactions according to the WAO Grading System for Systemic Allergic Reaction n (%) Patients RPT904 Q8W (N = 46) RPT904 Q12W (N = 46) Omalizumab Q4W (N = 45) Any TEAE 31 (67.4) 33 (71.7) 29 (64.4) Treatment-related 13 (28.3) 12 (26.1) 10 (22.2) Treatment-related Serious TEAEs 0 (0.0) 0 (0.0) 0 (0.0) Treatment-related AESI† 0 (0.0) 0 (0.0) 0 (0.0) TEAE leading to discontinuation 0 (0.0) 0 (0.0) 0 (0.0) TEAE leading to death 0 (0.0) 0 (0.0) 0 (0.0) RPT904 was well tolerated with no drug related SAEs or discontinuations and no AEs of special interest (i.e. anaphylaxis)

------

![Slide 14](rapt-ex99_1s14.jpg)

Comments from Dr. Ana Maria Giménez-Arnau, MD PhD Dr. Gimenez-Arnau is a consultant to RAPT. Professor at the Hospital del Mar Research Institute (IMIM) and Associate Professor of Dermatology at Universitat Pompeu Fabra in Barcelona Specialist in immunoallergic skin diseases More than 300 international scientific publications and 250 national publications, including textbooks on inflammatory skin diseases Co-author and investigator for key CSU trials, including remibrutinib (REMIX 1 and 2), dupilumab (LIBERTY-CSU) and ligelizumab (PEARL 1 and 2)

------

![Slide 15](rapt-ex99_1s15.jpg)

Results from this randomized double-blind phase 2 study show that extended half life and pharmacodynamic effects of RPT904 translate to durable clinical benefit A single 300 mg dose of RPT904 showed numerically superior efficacy to four 300 mg doses of omalizumab at week 16\* Data support promise of best-in-class profile across multiple indications We believe results support moving to pivotal Phase 3 studies in CSU Jeyou and RAPT to approach regulatory agencies in respective territories to discuss potential registrational paths to approval RAPT's Phase 2b in food allergy is on track to start before end of year with topline data expected 1H 2027 \*Study was not a formal non-inferiority study; no statistical hypothesis was tested Conclusions

------

![Slide 16](rapt-ex99_1s16.jpg)

RPT904 Food Allergy Phase 2b Trial Design Primary Endpoint: Prespecified threshold by oral food challenge N=100 (2:2:1 Q12W, Q8W regimens and placebo) US/Canada/Australia clinical sites FPI in 2H 2025, ~18 months from FPI to topline data Treatment Extension and Placebo Crossover RPT904 Q12W regimen (N=40) Adolescents and adults with ≥1 documented food allergy confirmed by skin-prick, lab testing, and oral food challenge Screening RPT904 Q8W regimen (N=40) Placebo (N=20) Randomization (2:2:1) Treatment 1 Treatment Duration (Weeks) Oral Food Challenge 24 Oral Food Challenge Oral Food Challenge Primary Endpoint Randomized, Double-Blind, Placebo-Controlled Study of RPT904 Monotherapy

------

![Slide 17](rapt-ex99_1s17.jpg)

1H 2025 2H 2025 1H 2026 2H 2026 1H 2027 2H 2027 FA Phase 2b Start N=100 Topline Data CSU Phase 2 or 3 Start Phase 2 CSU Data N=135 RPT904 Clinical Development Overview and Anticipated Milestones Phase 2 Asthma Data N=60 Phase 3 CSU Start Phase 3 Asthma Start PK/PD Data

------

![Slide 18](rapt-ex99_1s18.jpg)

Thank You Please visit www.rapt.com