# EDGAR Filing Document

**Accession Number:** 0001673772
**File Stem:** 0001193125-26-015978
**Filing Date:** 2026-1
**Character Count:** 55828
**Document Hash:** 5baef8194f08377aafe9c66f36c03c2a
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-26-015978.hdr.sgml**: 20260120

**ACCESSION NUMBER**: 0001193125-26-015978

**CONFORMED SUBMISSION TYPE**: SC14D9C

**PUBLIC DOCUMENT COUNT**: 5

**FILED AS OF DATE**: 20260120

**DATE AS OF CHANGE**: 20260120

**SUBJECT COMPANY**: 

**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:** SC14D9C
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-91191
- **FILM NUMBER:** 26541131

**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
**FILED BY**: 

**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:** SC14D9C

**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

**UNITED STATES** 

**SECURITIES AND EXCHANGE COMMISSION** 

**Washington, D.C. 20549** 

**SCHEDULE 14D-9** 

**Solicitation/Recommendation Statement** 

**Under Section 14(d)(4) of the Securities Exchange Act of 1934** 

## RAPT Therapeutics, Inc.
**(Name of Subject Company)** 

**(Name of Person Filing Statement)** 

**Common Stock, $0.0001 par value per share** 

**(Title of Class of Securities)** 

**75382E208** 

**(CUSIP Number of Class of Securities)** 

**Brian Wong** 

**President and Chief Executive Officer** 

**RAPT Therapeutics, Inc.** 

**561 Eccles Avenue** 

**South San Francisco, California 94080** 

**(650) 489-9000** 

**(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications** 

**on Behalf of the Person Filing Statement)** 

***With copies to:***

**Jamie Leigh** 

**Courtney M.W. Tygesson** 

**Bill Roegge** 

**Lindsey O'Crump** 

**Cooley LLP** 

**3 Embarcadero Center, 20th Floor** 

**San Francisco, CA 94111** 

**(415) 693-2000** 

☒ Check the box if the filing relates solely to preliminary communications made before the commencement of a
tender offer.

------

This Schedule 14D-9 filing consists of certain communications relating to the proposed acquisition of RAPT Therapeutics, Inc., a Delaware corporation (the "***Company***" or "***RAPT Therapeutics***") by GlaxoSmithKline LLC, a Delaware limited liability company ("***Parent***"), pursuant to the terms and subject to the conditions of an Agreement and Plan of Merger, dated as of January 19, 2026 (the "***Merger Agreement***"), by and among the Company, Parent, Redrose Acquisition Co., a Delaware corporation and a wholly owned subsidiary of Parent ("***Purchaser***"), and solely for purposes of providing a guaranty pursuant to Section 8.11 of the Merger Agreement, GSK plc, a public limited company organized under the laws of England and Wales ("***Ultimate Parent***" or "***GSK***"). Pursuant to the Merger Agreement, and upon the terms and subject to the conditions thereof, Parent has agreed to cause Purchaser to commence a tender offer (the "***Offer***"), no later than February 2, 2026, to purchase all of the outstanding shares of common stock of the Company, par value $0.0001 per share (the "***Shares***"), at a price of $58.00 per Share, without interest and subject to reduction for any applicable withholding taxes, upon the terms and subject to the conditions set forth in the Merger Agreement. If successful, following completion of the Offer and subject to the terms and conditions of the Merger Agreement, Purchaser will be merged with and into the Company (the "***Merger***") pursuant to Section 251(h) of the General Corporation Law of the State of Delaware, with the Company continuing as the surviving corporation in the Merger.

This Schedule 14D-9 filing consists of the following documents relating to the proposed Offer and the Merger:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Exhibit 99.1: Email from Brian Wong, M.D., Ph.D., President and Chief Executive Officer of the Company, to
employees, dated January 20, 2026.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Exhibit 99.2: Employee FAQ, dated January 20, 2026.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Exhibit 99.3: Company All Staff Meeting Remarks, delivered by Brian Wong, M.D., Ph.D., President and Chief
Executive Officer of the Company, dated January 20, 2026.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Exhibit 99.4: Investor FAQ, dated January 20, 2026.

**<u>Important Information about the Tender Offer and Where to Find It</u>**

The Offer for the outstanding common stock of RAPT Therapeutics referred to in this communication has not yet commenced. The description contained in this communication is neither an offer to purchase nor a solicitation of an offer to sell any securities, nor is it a substitute for the tender offer materials that Ultimate Parent, Parent and Purchaser will file with the SEC. The solicitation and offer to purchase RAPT Therapeutics' common stock will only be made pursuant to an offer to purchase and related tender offer materials. At the time the Offer is commenced, Ultimate Parent, Parent and Purchaser will file a tender offer statement on Schedule TO and thereafter RAPT Therapeutics will file a solicitation/recommendation statement on Schedule 14D-9 with the SEC with respect to the Offer.

THE TENDER OFFER MATERIALS (INCLUDING AN OFFER TO PURCHASE, A RELATED LETTER OF TRANSMITTAL AND CERTAIN OTHER OFFER DOCUMENTS) AND THE SOLICITATION/RECOMMENDATION STATEMENT ON SCHEDULE 14D-9, AS THEY MAY BE AMENDED OR SUPPLEMENTED FROM TIME TO TIME, WILL CONTAIN IMPORTANT INFORMATION. ANY HOLDERS OF RAPT THERAPEUTICS SHARES ARE URGED TO READ THESE DOCUMENTS CAREFULLY WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION THAT HOLDERS SHOULD CONSIDER BEFORE MAKING ANY DECISION REGARDING TENDERING THEIR SHARES IN THE OFFER.

The offer to purchase, the letter of transmittal, the solicitation/recommendation statement and related offer documents will be made available for free at the SEC's website at www.sec.gov. Copies of those offer documents and all other documents filed by Ultimate Parent, Parent and Purchaser and RAPT Therapeutics will be made available at no charge by directing a request to the information agent for the Offer, which will be named in the Schedule TO to be filed with the SEC. Copies of the solicitation/recommendation statement on Schedule 14D-9 to be filed with the SEC by RAPT Therapeutics will be available free of charge on RAPT Therapeutics' investor relations website at www.investors.rapt.com.

------

In addition, RAPT Therapeutics files annual, quarterly and current reports and other information with the SEC, which are also made available free of charge on RAPT Therapeutics' investor relations website at https://investors.rapt.com/investor-relations and at the SEC's website at www.sec.gov.

**<u>Cautionary Note Regarding Forward-Looking Statements</u>**

This communication contains forward-looking statements that involve risks and uncertainties relating to future events and the future performance of RAPT Therapeutics and GSK, including statements relating to the ability to complete and the timing of completion of the transactions contemplated by the Merger Agreement, including the anticipated occurrence, manner and timing of the proposed Offer, the parties' ability to satisfy the conditions to the consummation of the Offer and the other conditions to the consummation of the subsequent Merger set forth in the Merger Agreement, the possibility of any termination of the Merger Agreement, and the prospective benefits of the proposed transaction, and other statements that are not historical facts. The forward-looking statements contained in this communication are based on current expectations and assumptions that are subject to risks and uncertainties which may cause actual results to differ materially from the forward-looking statements. These statements may contain words such as "may," "will," "would," "could," "expect," "anticipate," "intend," "plan," "believe," "estimate," "project," "seek," "should," "strategy," "future," "opportunity," "potential" or other similar words and expressions indicating future results. Risks that may cause these forward-looking statements to be inaccurate include, without limitation: uncertainties as to the timing of the Offer; uncertainties as to how many of RAPT Therapeutics' stockholders will tender their stock in the Offer; the possibility that competing offers or acquisition proposals will be made; the possibility that various closing conditions for the transaction may not be satisfied or waived, including that a governmental entity may prohibit, delay, or refuse to grant approval for the consummation of the transaction (or only grant approval subject to adverse conditions or limitations); the difficulty of predicting the timing or outcome of regulatory approvals or actions, if any; the occurrence of any event, change or other circumstance that could give rise to the termination of the Merger Agreement; the possibility that the proposed transaction does not close; negative effects of the announcement of the proposed transaction on the market price of RAPT Therapeutics' common stock or RAPT Therapeutics' operating results; unexpected significant transaction costs; the risk of litigation and/or regulatory actions related to the proposed transaction; potential adverse reactions or changes to business relationships resulting from the proposed acquisition, the effect of the announcement, pendency or consummation of the acquisition on the ability of RAPT Therapeutics to retain and hire key personnel or maintain key vendor, supplier or partner relationships; risks arising from data protection and cross-border data transfer laws and regulations in jurisdictions where the parties operate, including the People's Republic of China; and the potential effect of the transaction on RAPT Therapeutics' clinical and preclinical pipeline. While the list of factors presented here is representative, no list should be considered a statement of all potential risks, uncertainties or assumptions that could have a material adverse effect on RAPT Therapeutics' consolidated financial condition or results of operations. The foregoing factors should be read in conjunction with the risks and cautionary statements discussed or identified in the parties' public filings with the U.S. Securities and Exchange Commission (the "***SEC***"), including those described from time to time under the caption "Risk Factors" and elsewhere in RAPT Therapeutics' filings and reports with the SEC, including RAPT Therapeutics' Annual Report on Form 10-K for the fiscal year ended December 31, 2024 and Quarterly Reports on Form 10-Q for the quarterly periods ended March 31, 2025, June 30, 2025, and September 30, 2025, or in GSK's Annual Report on Form 20-F for the fiscal year ended December 31, 2024 filed with the SEC by GSK, as well as the Tender Offer Statement on Schedule TO and related tender offer documents to be filed by Ultimate Parent, Parent and Purchaser, and the Solicitation/Recommendation Statement on Schedule 14D-9 to be filed by RAPT Therapeutics. Any forward-looking statements are made based on the current beliefs and judgments of RAPT Therapeutics' and GSK's management, and the reader is cautioned not to rely on any such forward-looking statements. Except as required by law, RAPT Therapeutics and GSK do not undertake any obligation to update (publicly or otherwise) any forward-looking statement, including without limitation any financial projection or guidance, whether as a result of new information, future events, or otherwise.

------

**Exhibit Index** 

---

| | |
|:---|:---|
| **Exhibit**<br> **Number** | **Description** |
| 99.1 | [Email from Brian Wong, M.D., Ph.D., President and Chief Executive Officer of the Company, to employees, dated January 20, 2026.](d80151dex991.htm) |
| 99.2 | [Employee FAQ, dated January 20, 2026.](d80151dex992.htm) |
| 99.3 | [Company All Staff Meeting Remarks, delivered by Brian Wong, M.D., Ph.D., President and Chief Executive Officer of the Company, dated January 20, 2026.](d80151dex993.htm) |
| 99.4 | [Investor FAQ, dated January 20, 2026.](d80151dex994.htm) |

---

## Exhibit 99.1

**Exhibit 99.1** 

Subject: Important Company News

Dear Team,

Moments ago, we and GSK, a global pharmaceutical company with deep development capabilities in immunology and inflammation, and an extensive commercial footprint in allergy, announced that we have entered into a definitive agreement to be acquired by GSK for approximately $2.2 billion.

Gaining the attention of GSK is a testament to what we've built as an organization. After careful thought, deliberation and consideration, the board and management determined that this is an attractive path forward for our programs, particularly the opportunity we envision for ozureprubart in food allergy, which will benefit from the resources, infrastructure, and capabilities that a global organization like GSK offers. Ultimately, we believe this strategic agreement brings added value to our pipeline, patients, and stockholders.

**What happens now?** 

The acquisition is expected to be completed in the first quarter of 2026, subject to regulatory review and other customary closing conditions.

Until the acquisition closes, it is business as usual. It is important to continue executing on our objectives to advance our programs. During this time, your role, manager, compensation, and benefits remain the same.

**What happens next?** 

At this point, we do not yet have clarity on the future organizational structure. The companies will work together on integration planning and many of you may be involved in those discussions. We are committed to communicating with you transparently as soon as information becomes available and decisions are made.

**All Hands Meeting Today** 

I'm sure you have a number of questions related to this announcement. To that end, we will host an All Staff meeting Tuesday, January 20<sup>th</sup> at 9:00am PT. In addition, the Senior Management Team will make ourselves available for one-on-one meetings.

Thank you for your commitment and dedication to RAPT's mission and vision. I'm incredibly proud of what we've accomplished and the resilience our team has demonstrated over the years. We've been driven by our science and commitment to patients – attributes that have led to the opportunity announced today.

------

With gratitude and my best regards,

Brian

**Important Information about the Tender Offer and Where to Find It** 

The tender offer (the "Offer") for the outstanding common stock of RAPT Therapeutics referred to in this communication has not yet commenced. The description contained in this communication is neither an offer to purchase nor a solicitation of an offer to sell any securities, nor is it a substitute for the tender offer materials that GSK and its acquisition subsidiary will file with the SEC. The solicitation and offer to purchase RAPT Therapeutics' common stock will only be made pursuant to an offer to purchase and related tender offer materials. At the time the Offer is commenced, GSK will file a tender offer statement on Schedule TO and thereafter RAPT Therapeutics will file a solicitation/recommendation statement on Schedule 14D-9 with the SEC with respect to the Offer.

THE TENDER OFFER MATERIALS (INCLUDING AN OFFER TO PURCHASE, A RELATED LETTER OF TRANSMITTAL AND CERTAIN OTHER OFFER DOCUMENTS) AND THE SOLICITATION/RECOMMENDATION STATEMENT ON SCHEDULE 14D-9, AS THEY MAY BE AMENDED OR SUPPLEMENTED FROM TIME TO TIME, WILL CONTAIN IMPORTANT INFORMATION. ANY HOLDERS OF RAPT THERAPEUTICS SHARES ARE URGED TO READ THESE DOCUMENTS CAREFULLY WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION THAT HOLDERS SHOULD CONSIDER BEFORE MAKING ANY DECISION REGARDING TENDERING THEIR SHARES IN THE OFFER.

The offer to purchase, the letter of transmittal, the solicitation/recommendation statement and related offer documents will be made available for free at the SEC's website at www.sec.gov. Copies of those offer documents and all other documents filed by GSK and RAPT Therapeutics will be made available at no charge by directing a request to the information agent for the Offer, which will be named in the Schedule TO to be filed with the SEC. Copies of the solicitation/recommendation statement on Schedule 14D-9 to be filed with the SEC by RAPT Therapeutics will be available free of charge on RAPT Therapeutics' investor relations website at www.investors.rapt.com.

In addition, RAPT Therapeutics files annual, quarterly and current reports and other information with the SEC, which are also made available free of charge on RAPT Therapeutics' investor relations website at www.investors.rapt.com and at the SEC's website at www.sec.gov.

------

**Forward-Looking Statements Disclaimer** 

This communication contains forward-looking statements that involve risks and uncertainties relating to future events and the future performance of RAPT Therapeutics and GSK, including statements relating to the ability to complete and the timing of completion of the transactions contemplated by the Agreement and Plan of Merger dated as of January 19, 2026 by and among RAPT Therapeutics, GSK, and the other parties thereto (the "Merger Agreement"), including the anticipated occurrence, manner and timing of the proposed tender offer, the parties' ability to satisfy the conditions to the consummation of the tender offer and the other conditions to the consummation of the subsequent merger set forth in the Merger Agreement, the possibility of any termination of the Merger Agreement, and the prospective benefits of the proposed transaction, and other statements that are not historical facts. The forward-looking statements contained in this communication are based on current expectations and assumptions that are subject to risks and uncertainties which may cause actual results to differ materially from the forward-looking statements. These statements may contain words such as "may," "will," "would," "could," "expect," "anticipate," "intend," "plan," "believe," "estimate," "project," "seek," "should," "strategy," "future," "opportunity," "potential" or other similar words and expressions indicating future results. Risks that may cause these forward-looking statements to be inaccurate include, without limitation: uncertainties as to the timing of the tender offer; uncertainties as to how many of RAPT Therapeutics' stockholders will tender their stock in the offer; the possibility that competing offers or acquisition proposals will be made; the possibility that various closing conditions for the transaction may not be satisfied or waived, including that a governmental entity may prohibit, delay, or refuse to grant approval for the consummation of the transaction (or only grant approval subject to adverse conditions or limitations); the difficulty of predicting the timing or outcome of regulatory approvals or actions, if any; the occurrence of any event, change or other circumstance that could give rise to the termination of the Merger Agreement; the possibility that the proposed transaction does not close; negative effects of the announcement of the proposed transaction on the market price of RAPT Therapeutics' common stock or RAPT Therapeutics' operating results; unexpected significant transaction costs; the risk of litigation and/or regulatory actions related to the proposed transaction; potential adverse reactions or changes to business relationships resulting from the proposed acquisition, the effect of the announcement, pendency or consummation of the

------

acquisition on the ability of RAPT Therapeutics to retain and hire key personnel or maintain key vendor, supplier or partner relationships; risks arising from data protection and cross-border data transfer laws and regulations in jurisdictions where the parties operate, including the People's Republic of China; and the potential effect of the transaction on RAPT Therapeutics' clinical and preclinical pipeline. While the list of factors presented here is representative, no list should be considered a statement of all potential risks, uncertainties or assumptions that could have a material adverse effect on RAPT Therapeutics' consolidated financial condition or results of operations. The foregoing factors should be read in conjunction with the risks and cautionary statements discussed or identified in the parties' public filings with the U.S. Securities and Exchange Commission (the "SEC"), including those described from time to time under the caption "Risk Factors" and elsewhere in RAPT Therapeutics' filings and reports with the SEC, including RAPT Therapeutics' Annual Report on Form 10-K for the fiscal year ended December 31, 2024 and Quarterly Reports on Form 10-Q for the quarterly periods ended March 31, 2025, June 30, 2025, and September 30, 2025, or in GSK's Annual Report on Form 20-F for the fiscal year ended December 31, 2024 filed with the SEC by GSK, as well as the Tender Offer Statement on Schedule TO and related tender offer documents to be filed by GSK and its acquisition subsidiary, and the Solicitation/Recommendation Statement on Schedule 14D-9 to be filed by RAPT Therapeutics. Any forward-looking statements are made based on the current beliefs and judgments of RAPT Therapeutics' and GSK's management, and the reader is cautioned not to rely on any such forward-looking statements. Except as required by law, RAPT Therapeutics and GSK do not undertake any obligation to update (publicly or otherwise) any forward-looking statement, including without limitation any financial projection or guidance, whether as a result of new information, future events, or otherwise.

## Exhibit 99.2

**Exhibit 99.2** 

Employee FAQ

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**1.** **Why is RAPT agreeing to this transaction with GSK?** 

After careful thought and consideration, the board and management have determined that this is an attractive path forward for our programs, particularly the opportunity we envision for ozureprubart in food allergy, which will benefit from the resources, infrastructure, and capabilities that a global organization like GSK offers. Ultimately, we believe this strategic agreement will bring added value to our pipeline, patients, and stockholders.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**2.** **When is the transaction expected to close?** 

The acquisition is expected to be completed in the first quarter of 2026, subject to regulatory review and other customary closing conditions.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**3.** **What does this transaction mean to me and my day-to-day activities?** 

Until the acquisition closes, it is business as usual. It is important to continue executing on our objectives to advance our programs.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**4.** **What is the go-forward plan for RAPT R&D programs?** 

We will continue to advance our programs as planned between now and the closing of the transaction. RAPT will operate independently until then and will work closely with GSK on an integration plan.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**5.** **Will our prestige clinical trial be impacted?** 

It is important that we continue to advance ozureprubart in the clinic and we ask all of you to help maintain our objectives associated with clinical trial enrollment and completion.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**6.** **Will my job title and manager and compensation/benefits stay the same?** 

Until the acquisition closes, it is business as usual. Your role, manager, compensation, and benefits remain the same. It is important that we continue to execute on our objectives to advance our programs.

GSK has committed that for a one-year period after closing, it will maintain for each retained employee (a) base salary/wages and target cash incentive opportunities that are no less favorable than those provided by RAPT to such employee as of immediately before the closing, and (b) benefits (excluding severance pay and benefits, equity or equity-based compensation, retention or change of control related compensation and benefits) that, taken together, are no less favorable in the aggregate than those provided by RAPT to such employee as of immediately before the closing.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**7.** **Will I receive my year end 2025 bonus and will my 2026 merit increase be impacted?** 

2025 bonuses will be paid out as per our normal practice and 2026 merit increases are unaffected.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**8.** **Will I get an equity grant in 2026?** 

In light of the pending acquisition, no additional grant of equity is planned for 2026.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**9.** **What will happen to my RAPT stock, stock options and/or RSUs at the closing of the transaction?** 

As part of the transaction, all shares of RAPT stock will be acquired by GSK for the deal price of $58.00 per share.

All outstanding options and RSUs granted on or prior to March 1, 2025 (whether vested or unvested) will be paid out in an amount equal to $58 less the applicable exercise price for each underlying share after the closing of the transaction.

For any outstanding options and RSUs granted to our employees after March 1, 2025:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Any portion of the award that is vested as of the closing of the transaction and 50% of the portion of the award
that is unvested as of the closing of the transaction will be paid out in an amount equal to $58 less the applicable exercise price for each underlying share after the closing of the transaction;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• The remaining 50% of the unvested portion of the award will vest and be paid out nine months following the
closing of the transaction (or earlier in the event of an involuntary termination not for cause or a resignation for good reason) in an amount equal to $58 less the applicable exercise price for each underlying share.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**10.** **What will happen to the ESPP?** 

Other than any offering period currently outstanding under RAPT's Amended and Restated 2019 Employee Stock Purchase Plan (the "**ESPP**"), no new ESPP offering period will be authorized or commenced. If the closing occurs before the end of an offering or purchase period, that period will be shortened so that the last purchase date occurs no later than the last business day before the closing, and your accumulated contributions will be used to purchase shares at that time. The ESPP will terminate on the closing date of the transaction.

------

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**11.** **How will we be integrated into the GSK organization? Will senior management retain their positions?** 

For now until closing, things are 'business as usual' for all of us, including our leadership team. At this point, we do not have clarity on the future organizational structure. The companies will work together on integration planning and many of you may be involved in those discussions. We are committed to communicating with you transparently as soon as information becomes available and decisions are made.

**Important Information about the Tender Offer and Where to Find It** 

The tender offer (the "Offer") for the outstanding common stock of RAPT Therapeutics referred to in this communication has not yet commenced. The description contained in this communication is neither an offer to purchase nor a solicitation of an offer to sell any securities, nor is it a substitute for the tender offer materials that GSK and its acquisition subsidiary will file with the SEC. The solicitation and offer to purchase RAPT Therapeutics' common stock will only be made pursuant to an offer to purchase and related tender offer materials. At the time the Offer is commenced, GSK will file a tender offer statement on Schedule TO and thereafter RAPT Therapeutics will file a solicitation/recommendation statement on Schedule 14D-9 with the SEC with respect to the Offer.

THE TENDER OFFER MATERIALS (INCLUDING AN OFFER TO PURCHASE, A RELATED LETTER OF TRANSMITTAL AND CERTAIN OTHER OFFER DOCUMENTS) AND THE SOLICITATION/RECOMMENDATION STATEMENT ON SCHEDULE 14D-9, AS THEY MAY BE AMENDED OR SUPPLEMENTED FROM TIME TO TIME, WILL CONTAIN IMPORTANT INFORMATION. ANY HOLDERS OF RAPT THERAPEUTICS SHARES ARE URGED TO READ THESE DOCUMENTS CAREFULLY WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION THAT HOLDERS SHOULD CONSIDER BEFORE MAKING ANY DECISION REGARDING TENDERING THEIR SHARES IN THE OFFER.

The offer to purchase, the letter of transmittal, the solicitation/recommendation statement and related offer documents will be made available for free at the SEC's website at www.sec.gov. Copies of those offer documents and all other documents filed by GSK and RAPT Therapeutics will be made available at no charge by directing a request to the information agent for the Offer, which will be named in the Schedule TO to be filed with the SEC. Copies of the solicitation/recommendation statement on Schedule 14D-9 to be filed with the SEC by RAPT Therapeutics will be available free of charge on RAPT Therapeutics' investor relations website at www.investors.rapt.com.

In addition, RAPT Therapeutics files annual, quarterly and current reports and other information with the SEC, which are also made available free of charge on RAPT Therapeutics' investor relations website at www.investors.rapt.com and at the SEC's website at www.sec.gov.

------

**Forward-Looking Statements Disclaimer** 

This communication contains forward-looking statements that involve risks and uncertainties relating to future events and the future performance of RAPT Therapeutics and GSK, including statements relating to the ability to complete and the timing of completion of the transactions contemplated by the Agreement and Plan of Merger dated as of January 19, 2026 by and among RAPT Therapeutics, GSK, and the other parties thereto (the "Merger Agreement"), including the anticipated occurrence, manner and timing of the proposed tender offer, the parties' ability to satisfy the conditions to the consummation of the tender offer and the other conditions to the consummation of the subsequent merger set forth in the Merger Agreement, the possibility of any termination of the Merger Agreement, and the prospective benefits of the proposed transaction, and other statements that are not historical facts. The forward-looking statements contained in this communication are based on current expectations and assumptions that are subject to risks and uncertainties which may cause actual results to differ materially from the forward-looking statements. These statements may contain words such as "may," "will," "would," "could," "expect," "anticipate," "intend," "plan," "believe," "estimate," "project," "seek," "should," "strategy," "future," "opportunity," "potential" or other similar words and expressions indicating future results. Risks that may cause these forward-looking statements to be inaccurate include, without limitation: uncertainties as to the timing of the tender offer; uncertainties as to how many of RAPT Therapeutics' stockholders will tender their stock in the offer; the possibility that competing offers or acquisition proposals will be made; the possibility that various closing conditions for the transaction may not be satisfied or waived, including that a governmental entity may prohibit, delay, or refuse to grant approval for the consummation of the transaction (or only grant approval subject to adverse conditions or limitations); the difficulty of predicting the timing or outcome of

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regulatory approvals or actions, if any; the occurrence of any event, change or other circumstance that could give rise to the termination of the Merger Agreement; the possibility that the proposed transaction does not close; negative effects of the announcement of the proposed transaction on the market price of RAPT Therapeutics' common stock or RAPT Therapeutics' operating results; unexpected significant transaction costs; the risk of litigation and/or regulatory actions related to the proposed transaction; potential adverse reactions or changes to business relationships resulting from the proposed acquisition, the effect of the announcement, pendency or consummation of the acquisition on the ability of RAPT Therapeutics to retain and hire key personnel or maintain key vendor, supplier or partner relationships; risks arising from data protection and cross-border data transfer laws and regulations in jurisdictions where the parties operate, including the People's Republic of China; and the potential effect of the transaction on RAPT Therapeutics' clinical and preclinical pipeline. While the list of factors presented here is representative, no list should be considered a statement of all potential risks, uncertainties or assumptions that could have a material adverse effect on RAPT Therapeutics' consolidated financial condition or results of operations. The foregoing factors should be read in conjunction with the risks and cautionary statements discussed or identified in the parties' public filings with the U.S. Securities and Exchange Commission (the "SEC"), including those described from time to time under the caption "Risk Factors" and elsewhere in RAPT Therapeutics' filings and reports with the SEC, including RAPT Therapeutics' Annual Report on Form 10-K for the fiscal year ended December 31, 2024 and Quarterly Reports on Form 10-Q for the quarterly periods ended March 31, 2025, June 30, 2025, and September 30, 2025, or in GSK's Annual Report on Form 20-F for the fiscal year ended December 31, 2024 filed with the SEC by GSK, as well as the Tender Offer Statement on Schedule TO and related tender offer documents to be filed by GSK and its acquisition subsidiary, and the Solicitation/Recommendation Statement on Schedule 14D-9 to be filed by RAPT Therapeutics. Any forward-looking statements are made based on the current beliefs and judgments of RAPT Therapeutics' and GSK's management, and the reader is cautioned not to rely on any such forward-looking statements. Except as required by law, RAPT Therapeutics and GSK do not undertake any obligation to update (publicly or otherwise) any forward-looking statement, including without limitation any financial projection or guidance, whether as a result of new information, future events, or otherwise.

## Exhibit 99.3

**Exhibit 99.3** 

**All Staff Meeting – CEO Remarks** 

Good morning, everyone.

Thank you for joining our All Staff meeting this morning, especially on short notice. Most of you already know that earlier today, we announced that RAPT has entered into an agreement to be acquired for approximately $2.2 billion by GSK, a global pharmaceutical company with deep development and commercialization capabilities.

At the outset, I want to thank you for your commitment and dedication to RAPT's mission and vision. I'm incredibly proud of what we've accomplished and the resilience our team has demonstrated over the years. We've been driven by our science and commitment to patients and that has led us to where we are today.

Gaining the attention of GSK is a testament to what we've built as an organization. After careful thought and consideration, the board and management have determined that this is an attractive path forward for our programs, particularly the opportunity we envision for ozureprubart in food allergy, which will benefit from the resources, infrastructure, and capabilities that a global organization like GSK offers. Ultimately, we believe this strategic agreement will bring added value to our pipeline, patients, and stockholders.

The acquisition is expected to be completed in the first quarter of 2026, subject to regulatory review and other customary closing conditions. Until the acquisition closes, it is business as usual. It is important we continue executing on our objectives to advance our programs. During this time, your role, manager, compensation, and benefits remain the same.

Over the next couple of months, we will work together with GSK on integration planning and many of you may be involved in those discussions. We are committed to communicating with you transparently as soon as information becomes available and decisions are made.

This is a significant moment for our company and for all of us. I'm sure you have many questions and a variety of emotions. We don't yet have all the answers, but I and rest of the senior management team are committed to sharing information with you as it becomes available and answering whatever questions we can.

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**Important Information about the Tender Offer and Where to Find It** 

The tender offer (the "Offer") for the outstanding common stock of RAPT Therapeutics referred to in this communication has not yet commenced. The description contained in this communication is neither an offer to purchase nor a solicitation of an offer to sell any securities, nor is it a substitute for the tender offer materials that GSK and its acquisition subsidiary will file with the SEC. The solicitation and offer to purchase RAPT Therapeutics' common stock will only be made pursuant to an offer to purchase and related tender offer materials. At the time the Offer is commenced, GSK will file a tender offer statement on Schedule TO and thereafter RAPT Therapeutics will file a solicitation/recommendation statement on Schedule 14D-9 with the SEC with respect to the Offer.

THE TENDER OFFER MATERIALS (INCLUDING AN OFFER TO PURCHASE, A RELATED LETTER OF TRANSMITTAL AND CERTAIN OTHER OFFER DOCUMENTS) AND THE SOLICITATION/RECOMMENDATION STATEMENT ON SCHEDULE 14D-9, AS THEY MAY BE AMENDED OR SUPPLEMENTED FROM TIME TO TIME, WILL CONTAIN IMPORTANT INFORMATION. ANY HOLDERS OF RAPT THERAPEUTICS SHARES ARE URGED TO READ THESE DOCUMENTS CAREFULLY WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION THAT HOLDERS SHOULD CONSIDER BEFORE MAKING ANY DECISION REGARDING TENDERING THEIR SHARES IN THE OFFER.

The offer to purchase, the letter of transmittal, the solicitation/recommendation statement and related offer documents will be made available for free at the SEC's website at www.sec.gov. Copies of those offer documents and all other documents filed by GSK and RAPT Therapeutics will be made available at no charge by directing a request to the information agent for the Offer, which will be named in the Schedule TO to be filed with the SEC. Copies of the solicitation/recommendation statement on Schedule 14D-9 to be filed with the SEC by RAPT Therapeutics will be available free of charge on RAPT Therapeutics' investor relations website at www.investors.rapt.com.

In addition, RAPT Therapeutics files annual, quarterly and current reports and other information with the SEC, which are also made available free of charge on RAPT Therapeutics' investor relations website at www.investors.rapt.com and at the SEC's website at www.sec.gov.

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**Forward-Looking Statements Disclaimer** 

This communication contains forward-looking statements that involve risks and uncertainties relating to future events and the future performance of RAPT Therapeutics and GSK, including statements relating to the ability to complete and the timing of completion of the transactions contemplated by the Agreement and Plan of Merger dated as of January 19, 2026 by and among RAPT Therapeutics, GSK, and the other parties thereto (the "Merger Agreement"), including the anticipated occurrence, manner and timing of the proposed tender offer, the parties' ability to satisfy the conditions to the consummation of the tender offer and the other conditions to the consummation of the subsequent merger set forth in the Merger Agreement, the possibility of any termination of the Merger Agreement, and the prospective benefits of the proposed transaction, and other statements that are not historical facts. The forward-looking statements contained in this communication are based on current expectations and assumptions that are subject to risks and uncertainties which may cause actual results to differ materially from the forward-looking statements. These statements may contain words such as "may," "will," "would," "could," "expect," "anticipate," "intend," "plan," "believe," "estimate," "project," "seek," "should," "strategy," "future," "opportunity," "potential" or other similar words and expressions indicating future results. Risks that may cause these forward-looking statements to be inaccurate include, without limitation: uncertainties as to the timing of the tender offer; uncertainties as to how many of RAPT Therapeutics' stockholders will tender their stock in the offer; the possibility that competing offers or acquisition proposals will be made; the possibility that various closing conditions for the transaction may not be satisfied or waived, including that a governmental entity may prohibit, delay, or refuse to grant approval for the consummation of the transaction (or only grant approval subject to adverse conditions or limitations); the difficulty of predicting the timing or outcome of regulatory approvals or actions, if any; the occurrence of any event, change or other circumstance that could give rise to the termination of the Merger Agreement; the possibility that the proposed transaction does not close; negative effects of the announcement of the proposed transaction on the market price of RAPT Therapeutics' common stock or RAPT Therapeutics' operating results; unexpected significant transaction costs; the risk of litigation and/or regulatory actions related to the proposed transaction; potential adverse reactions or changes to business relationships resulting from the proposed acquisition, the effect of the announcement, pendency or consummation of the acquisition on the ability of RAPT Therapeutics to retain and hire key personnel or maintain key vendor, supplier or partner relationships; risks arising from data protection and cross-border data transfer laws and regulations in jurisdictions where the parties operate, including the People's Republic of China; and the potential effect of the transaction on RAPT Therapeutics' clinical and preclinical pipeline. While the list of factors presented here is representative, no list should be considered a statement of all potential risks, uncertainties or assumptions that could have a material adverse effect on RAPT Therapeutics' consolidated financial condition or results of operations. The foregoing factors should be read in conjunction with the risks and cautionary statements discussed or identified in the parties' public filings with the U.S. Securities and Exchange Commission (the "SEC"), including those described from time to time under the caption "Risk Factors" and elsewhere in RAPT Therapeutics' filings and reports with the SEC, including RAPT Therapeutics' Annual Report on Form 10-K for the fiscal year ended December 31, 2024 and Quarterly Reports on Form 10-Q for the quarterly periods ended March 31, 2025, June 30, 2025, and September 30, 2025, or in GSK's Annual Report on Form 20-F for the fiscal year ended December 31, 2024 filed with the SEC by GSK, as well as the Tender Offer Statement on Schedule TO and related tender offer documents to be

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filed by GSK and its acquisition subsidiary, and the Solicitation/Recommendation Statement on Schedule 14D-9 to be filed by RAPT Therapeutics. Any forward-looking statements are made based on the current beliefs and judgments of RAPT Therapeutics' and GSK's management, and the reader is cautioned not to rely on any such forward-looking statements. Except as required by law, RAPT Therapeutics and GSK do not undertake any obligation to update (publicly or otherwise) any forward-looking statement, including without limitation any financial projection or guidance, whether as a result of new information, future events, or otherwise.

## Exhibit 99.4

**Exhibit 99.4** 

**Investor FAQ** 

**1. What was announced?** 

RAPT has agreed to be acquired by GSK for $58.00 per share in cash, which represents an equity value of approximately $2.2 billion.

This transaction has the potential to bring GSK's global development and commercialization capabilities, resources and infrastructure to our programs and ultimately bring added value to our pipeline, patients, and stockholders.

**2. Why does this transaction make sense for RAPT investors?** 

We believe this is the right transaction for our investors.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• The offer price represents a significant 65% premium to the last closing price (January 16, 2026) of RAPT prior
to the announcement of the transaction.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• The offer price also represents a 37% premium to the 52-week high of RAPT
shares.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• We believe the advancement of ozureprubart in food allergy will benefit from the resources, infrastructure, and
capabilities that a global organization like GSK offers

**3. What role will your executive team have after the merger?** 

For now until closing, things are 'business as usual' for RAPT, including our leadership team. Integration planning is in process and the go-forward organizational structure will be reviewed as part of that integration planning process. We expect to know more in the coming weeks.

**4. When will the tender offer be commenced?** 

GSK is obligated to commence a tender offer to acquire all of RAPT's outstanding shares for $58.00 per share in cash as promptly as practicable but no later than 10 business days after the date of the merger agreement. At the tender offer price, GSK is offering total consideration of approximately $2.24 billion for all outstanding shares.

Assuming a majority of the outstanding RAPT shares are tendered and not withdrawn, and subject to other customary closing conditions, including receipt of U.S. antitrust clearance, GSK is required to close the tender offer. RAPT shares that are not tendered will be converted into the right to receive the same $58.00 per share in cash paid in the tender offer, and RAPT stock will no longer be listed on the Nasdaq exchange. Following the consummation of the tender offer, RAPT will merge with and into a subsidiary of GSK in a second-step merger.

**5. When do you expect to file the Schedule 14D-9?** 

RAPT's Schedule 14D-9 will be filed on the same day as the commencement of the tender offer, which GSK is obligated to commence as promptly as practicable but no later than 10 business days after the date of the merger agreement.

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**6. When do you expect the transaction to close?** 

We expect to close the transaction in the first quarter of 2026, subject to satisfaction or waiver of required closing conditions, including receipt of U.S. antitrust clearance, and the tender of a majority of the outstanding RAPT shares.

**Important Information about the Tender Offer and Where to Find It** 

The tender offer (the "Offer") for the outstanding common stock of RAPT Therapeutics referred to in this communication has not yet commenced. The description contained in this communication is neither an offer to purchase nor a solicitation of an offer to sell any securities, nor is it a substitute for the tender offer materials that GSK and its acquisition subsidiary will file with the SEC. The solicitation and offer to purchase RAPT Therapeutics' common stock will only be made pursuant to an offer to purchase and related tender offer materials. At the time the Offer is commenced, GSK will file a tender offer statement on Schedule TO and thereafter RAPT Therapeutics will file a solicitation/recommendation statement on Schedule 14D-9 with the SEC with respect to the Offer.

THE TENDER OFFER MATERIALS (INCLUDING AN OFFER TO PURCHASE, A RELATED LETTER OF TRANSMITTAL AND CERTAIN OTHER OFFER DOCUMENTS) AND THE SOLICITATION/RECOMMENDATION STATEMENT ON SCHEDULE 14D-9, AS THEY MAY BE AMENDED OR SUPPLEMENTED FROM TIME TO TIME, WILL CONTAIN IMPORTANT INFORMATION. ANY HOLDERS OF RAPT THERAPEUTICS SHARES ARE URGED TO READ THESE DOCUMENTS CAREFULLY WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION THAT HOLDERS SHOULD CONSIDER BEFORE MAKING ANY DECISION REGARDING TENDERING THEIR SHARES IN THE OFFER.

The offer to purchase, the letter of transmittal, the solicitation/recommendation statement and related offer documents will be made available for free at the SEC's website at www.sec.gov. Copies of those offer documents and all other documents filed by GSK and RAPT Therapeutics will be made available at no charge by directing a request to the information agent for the Offer, which will be named in the Schedule TO to be filed with the SEC. Copies of the solicitation/recommendation statement on Schedule 14D-9 to be filed with the SEC by RAPT Therapeutics will be available free of charge on RAPT Therapeutics' investor relations website at www.investors.rapt.com.

In addition, RAPT Therapeutics files annual, quarterly and current reports and other information with the SEC, which are also made available free of charge on RAPT Therapeutics' investor relations website at www.investors.rapt.com and at the SEC's website at www.sec.gov.

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**Forward-Looking Statements Disclaimer** 

This communication contains forward-looking statements that involve risks and uncertainties relating to future events and the future performance of RAPT Therapeutics and GSK, including statements relating to the ability to complete and the timing of completion of the transactions contemplated by the Agreement and Plan of Merger dated as of January 19, 2026 by and among RAPT Therapeutics, GSK, and the other parties thereto (the "Merger Agreement"), including the anticipated occurrence, manner and timing of the proposed tender offer, the parties' ability to satisfy the conditions to the consummation of the tender offer and the other conditions to the consummation of the subsequent merger set forth in the Merger Agreement, the possibility of any termination of the Merger Agreement, and the prospective benefits of the proposed transaction, and other statements that are not historical facts. The forward-looking statements contained in this communication are based on current expectations and assumptions that are subject to risks and uncertainties which may cause actual results to differ materially from the forward-looking statements. These statements may contain words such as "may," "will," "would," "could," "expect," "anticipate," "intend," "plan," "believe," "estimate," "project," "seek," "should," "strategy," "future," "opportunity," "potential" or other similar words and expressions indicating future results. Risks that may cause these forward-looking statements to be inaccurate include, without limitation: uncertainties as to the timing of the tender offer; uncertainties as to how many of RAPT Therapeutics' stockholders will tender their stock in the offer; the possibility that competing offers or acquisition proposals will be made; the possibility that various closing conditions for the transaction may not be satisfied or waived, including that a governmental entity may prohibit, delay, or refuse to grant approval for the consummation of the transaction (or only grant approval subject to adverse conditions or limitations); the difficulty of predicting the timing or outcome of regulatory approvals or actions, if any; the occurrence of any event, change or other circumstance that could give rise to the termination of the Merger Agreement; the possibility that the proposed transaction does not close; negative effects of the announcement of the proposed transaction on the market price of RAPT Therapeutics' common stock or RAPT Therapeutics' operating results; unexpected significant transaction costs; the risk of litigation and/or regulatory actions related to the proposed transaction; potential adverse reactions or changes to business relationships resulting from the proposed acquisition, the effect of the announcement, pendency or consummation of the acquisition on the ability of RAPT Therapeutics to retain and hire key personnel or maintain key vendor, supplier or partner relationships; risks arising from data protection and cross-border data transfer laws and regulations in jurisdictions where the parties operate, including the People's Republic of China; and the potential effect of the transaction on RAPT Therapeutics' clinical and preclinical pipeline. While the list of factors presented here is representative, no list should be considered a statement of all potential risks, uncertainties or assumptions that could have a material adverse effect on RAPT Therapeutics' consolidated financial condition or results of operations. The foregoing factors should be read in conjunction with the risks and cautionary statements discussed or identified in the parties' public filings with the U.S. Securities and Exchange Commission (the "SEC"), including those described from time to time under the caption "Risk Factors" and elsewhere in RAPT Therapeutics' filings and reports with the SEC, including RAPT Therapeutics' Annual Report on Form 10-K for the fiscal year ended December 31, 2024 and Quarterly Reports on Form 10-Q for the quarterly periods ended March 31, 2025, June 30, 2025, and September 30, 2025, or in GSK's Annual Report on Form 20-F for the fiscal year ended December 31, 2024 filed with the SEC by GSK, as well as the Tender Offer

------

Statement on Schedule TO and related tender offer documents to be filed by GSK and its acquisition subsidiary, and the Solicitation/Recommendation Statement on Schedule 14D-9 to be filed by RAPT Therapeutics. Any forward-looking statements are made based on the current beliefs and judgments of RAPT Therapeutics' and GSK's management, and the reader is cautioned not to rely on any such forward-looking statements. Except as required by law, RAPT Therapeutics and GSK do not undertake any obligation to update (publicly or otherwise) any forward-looking statement, including without limitation any financial projection or guidance, whether as a result of new information, future events, or otherwise.