On this page of StockholderLetter.com we present the latest annual shareholder letter from RAPT Therapeutics, Inc. — ticker symbol RAPT. Reading current and past RAPT letters to shareholders can bring important insights into the investment thesis.

 •  4/14/2025 Letter Continued (Full PDF)
 •  4/7/2023 RAPT Stockholder Letter
 •  4/5/2024 RAPT Stockholder Letter
 •  More "Drugs & Pharmaceuticals" Category Stockholder Letters
 •  RAPT Benford's Law Stock Score = 71

RAPT Shareholder/Stockholder Letter Transcript:

2025 Proxy Statement
and
2024 Annual Report


April 2025
Dear Stockholders,
I am pleased to report on our vision for significant growth and momentum as we advance clinical
development of our lead drug candidate, RPT904, a novel half-life extended monoclonal
antibody designed to bind immunoglobin E (IgE), a key driver of several allergic diseases. 1
Pursuing Large Markets and Unmet Needs in Allergy
2024 was a transitional year for RAPT, which culminated in the acquisition of worldwide rights
(excluding mainland China, Hong Kong, Macau and Taiwan) to develop and commercialize
RPT904 through an exclusive license agreement with Jemincare Pharmaceutical Co., Ltd., a
leading pharmaceutical company in China. We believe RPT904 has potential as a best-in-class
therapeutic option compared to omalizumab (marketed as Xolair  ), an anti-IgE monoclonal
antibody approved for several allergic disorders. Our initial focus will be food allergy and we
plan to initiate a Phase 2b clinical trial of RPT904 in food allergy later in 2025. Separately,
Jemincare is conducting Phase 2 clinical trials of this promising asset in China in asthma and
chronic spontaneous urticaria (CSU). Should these mid-stage trials prove successful, they would
solidify our belief in the pipeline-in-a-product potential of RPT904 across multiple indications
and its potential to address the significant unmet needs of patients with those inflammatory
conditions.
Our confidence in RPT904 is based on two key factors:
1) RPT904 targets the same clinically validated binding site (epitope) as omalizumab,
but utilizes an innovative design for extended half-life and improved affinity. This
allows for the potential of RPT904 to reduce dosing frequency and improve
compliance and patient outcomes.
2) Data from Jemincare   s randomized, double-blinded, Phase 1 single-dose doseescalation study in 56 healthy volunteers in China confirmed the median half-life of
RPT904 was more than two times that of omalizumab at the same dose. In addition,
the pharmacokinetics of RPT904 were approximately dose-proportional and
pharmacodynamic analysis showed deeper and more sustained reduction of free IgE
This letter contains forward-looking statements. Please see the sections titled    Special Note Regarding
Forward-Looking Statements    and    Risk Factors    in the accompanying Annual Report on Form 10-K.
1

and higher total IgE accumulation by RPT904 compared to omalizumab at the same
dose. Reduction of free IgE by omalizumab is associated with efficacy across a range
of indications including food allergy and asthma.
Prioritizing Food Allergy
Although there are broad opportunities for RPT904, we are prioritizing development in food
allergy, which is a significant and growing health problem in the United States, Europe and
throughout the developed world and an area of high unmet medical need. According to Food
Allergy Research & Education (FARE), an organization dedicated to improving the lives of
people with food allergy through research, education and advocacy, over 17 million people in the
United States have been diagnosed with a food allergy, including approximately six million
children. Furthermore, FARE notes that approximately 40% of people with a food allergy are
allergic to more than one food and approximately half of food-allergic people in the United
States have had a severe reaction from their food allergy.
Traditional treatments include food avoidance, which does not eliminate risk, and oral
immunotherapy, which is burdensome, treats a single allergen and is associated with side effects,
including anaphylaxis. Despite these approaches, 3.4 million patients per year in the US require a
visit to the emergency room for food allergy-related reactions. This places a large burden on the
healthcare system and has a negative socioeconomic and quality of life impact on patients and
their families.
The approval of omalizumab last year as a treatment for food allergy was well received with
Roche reporting over 40,000 patients prescribed in the first three quarters after launch.
Compared to traditional therapies, omalizumab   s main advantages include its high response rate
and ability to treat multiple food allergies simultaneously. With an extended half-life, we believe
RPT904 has the potential to be dosed much less frequently than omalizumab (every 8 or 12
weeks compared to every 2 to 4 weeks) and has the potential to treat patients with high IgE or
high body weight who are not eligible to be treated with omalizumab. This profile should be
highly attractive to patients, prescribers and payers and should position RPT904 as the preferred
treatment option for food allergy.
Chronic Spontaneous Urticaria
We have also identified CSU as a priority indication for RPT904 right behind food allergy.
Omalizumab is the standard of care for the estimated 400 thousand CSU patients whose disease
is inadequately controlled with high-dose antihistamines. We believe that RPT904, with its lessfrequent dosing, would successfully compete with omalizumab and become the preferred
treatment option in this indication. Our partner Jemincare is currently conducting a Phase 2 trial
in CSU in China, which is expected to read out later this year. This Phase 2 trial, if successful,

would support our development in CSU, potentially including moving directly to a Phase 3
pivotal trial.
CCR4 in Inflammatory Disease
Despite our setback last year with zelnecirnon (RPT193), we continue to believe CCR4 is an
exciting drug target for inflammatory diseases and have efforts underway to identify a nextgeneration oral CCR4 antagonist. With our focus on allergy and inflammation, we have
deprioritized our cancer programs and are currently pursuing partnerships to further develop
tivumecirnon, our oral CCR4 antagonist that has shown promising results in several cancer
indications.
Strengthened Organizational Resources
For a development-stage company, prudent cash management is essential, particularly in the
turbulent markets that have plagued biopharmaceutical companies in recent years. In addition to
our disciplined budgets, we were pleased to execute a $150 million private placement last year
concurrent with the in-licensing of RPT904. We reported cash and marketable securities of $231
million as of December 31, 2024, and we expect our cash resources to support our planned
operations to our planned data readout from our Phase 2b clinical trial for RPT904 in food
allergy, which we expect in the first half of 2027.
Outlook for Growing Stockholder Value
We see a tremendous opportunity to grow stockholder value should the potential for RPT904 be
realized as envisioned. Food allergy alone represents a large, multibillion market, and we believe
RPT904 would be well positioned to become the treatment of choice for many food allergy
patients. As you know, drug development can be tricky and unpredictable. However, we believe
RPT904 has significant potential and are focused on executing our development plans later this
year.
We look forward to keeping you apprised of our progress. As always, we appreciate your
continued support as we seek to bring our transformative medicines to patients in need.
Sincerely,
Brian Wong, M.D., Ph.D.
President and CEO



 4/14/2025 Letter Continued (Full PDF)