GSK Strengthens Immunology Pipeline with $2.2 Billion RAPT Therapeutics Acquisition

GSK Strengthens Immunology Pipeline with $2.2 Billion RAPT Therapeutics Acquisition

(IN BRIEF) GSK has agreed to acquire RAPT Therapeutics in a transaction valued at approximately $2.2 billion, adding ozureprubart, a phase IIb long-acting anti-IgE antibody for food allergy prevention, to its Respiratory, Immunology & Inflammation pipeline. Designed to offer sustained protection with dosing every 12 weeks, ozureprubart has the potential to address significant unmet needs in food allergy treatment, particularly among pediatric patients. The deal strengthens GSK’s position in allergy and immunology and is expected to close in the first quarter of 2026.

(PRESS RELEASE) LONDON, 20-Jan-2026 — /EuropaWire/ — GSK plc has entered into a definitive agreement to acquire RAPT Therapeutics, a California-based, clinical-stage biopharmaceutical company focused on inflammatory and immunologic diseases, in a transaction that strengthens GSK’s Respiratory, Immunology & Inflammation pipeline. Central to the acquisition is ozureprubart, a long-acting anti-immunoglobulin E monoclonal antibody currently in phase IIb development for the prophylactic protection against food allergy reactions.

Ozureprubart targets IgE, a clinically validated pathway responsible for the majority of severe food allergy reactions. Approximately 94 percent of severe food allergies are IgE-mediated, yet current systemic anti-IgE therapies require injections every two to four weeks, creating a significant treatment burden, particularly for pediatric patients. Ozureprubart has the potential to offer sustained protection with dosing every 12 weeks, supporting improved treatment adherence and patient experience, while also expanding access to an estimated 25 percent of patients who are not eligible for existing therapies.

The asset aligns closely with GSK’s established commercial presence and prescriber relationships in allergy and immunology. Data from the phase IIb prestIgE trial evaluating ozureprubart as monotherapy are expected in 2027, with planned phase III studies to include both adult and pediatric populations at risk of severe allergic reactions. In the United States alone, more than 17 million people live with food allergies, resulting in over 3 million hospital and emergency care visits annually, highlighting the scale of unmet medical need.

Under the terms of the agreement, GSK will acquire all outstanding shares of RAPT Therapeutics for $58.00 per share in cash, representing an estimated equity value of $2.2 billion. Net of cash acquired, GSK’s upfront investment is expected to be approximately $1.9 billion. The transaction grants GSK global rights to ozureprubart, excluding mainland China, Macau, Taiwan, and Hong Kong, and includes future milestone and royalty obligations payable to RAPT’s partner, Shanghai Jeyou Pharmaceutical Co., Ltd.

The acquisition will be completed through a tender offer followed by a second-step merger under Delaware law, subject to customary closing conditions and regulatory approvals. The transaction is expected to close in the first quarter of 2026 and will be accounted for as a business combination.

Through this acquisition, GSK reinforces its strategy of selectively acquiring assets addressing validated biological targets and areas of clear unmet medical need, while advancing its ambition to deliver differentiated, long-acting therapies that can meaningfully improve outcomes for patients living with serious allergic and immunologic conditions.

Advisors

Evercore is acting as exclusive financial advisor and A&O Shearman is serving as legal counsel to GSK in connection with the transaction. J.P. Morgan Securities LLC is acting as exclusive financial advisor and Cooley LLP is serving as legal counsel to RAPT Therapeutics.

Additional information

This press announcement is for informational purposes only and is neither an offer to purchase nor a solicitation of an offer or a recommendation to sell securities, nor is it a substitute for the tender offer materials that GSK, GlaxoSmithKline LLC (“GSK LLC”) and its wholly-owned subsidiary, Redrose Acquisition Co. will file with the Securities and Exchange Commission (the “SEC”). The tender offer for the outstanding shares of RAPT Therapeutics common stock described in this press announcement has not commenced. At the time the tender offer is commenced, GSK, GSK LLC and Redrose Acquisition Co. will file, or will cause to be filed, a Schedule TO Tender Offer Statement with the SEC, and, thereafter, RAPT Therapeutics will file a Schedule 14D-9 Solicitation/Recommendation Statement with the SEC, in each case with respect to the tender offer. The Schedule TO Tender Offer Statement (including an offer to purchase, a related letter of transmittal and other offer documents) and the Schedule 14D-9 Solicitation/Recommendation Statement will contain important information that should be read carefully before any decision is made with respect to the tender offer. Those materials (once they become available) will be made available to RAPT Therapeutics stockholders at no expense to them by the information agent for the tender offer, which will be announced. In addition, those materials and all other documents filed by or caused to be filed by RAPT Therapeutics or GSK with the SEC will be available at no charge on the SEC’s website at www.sec.gov. In addition to the Schedule 14D-9 Solicitation/Recommendation Statement and Schedule TO Offer Statement (once each becomes available), RAPT Therapeutics and GSK file or furnish, as applicable, annual, quarterly and current reports and other information with the SEC. You may read and copy any reports or other information filed by RAPT Therapeutics at the SEC public reference room at 100 F Street, N.E., Washington, D.C. 20549. Please call the SEC at 1-800-0330 for further information on the public reference room. RAPT Therapeutics and GSK filings with the SEC are also available to the public from commercial document-retrieval services and at the SEC’s website at www.sec.gov.

About food allergies

In the US, over 17 million people are diagnosed with food allergies, with more than 1.3 million people suffering severe reactions.^2,3,4 Notably, 65% of severe food allergy patients are children and adolescents.¹ This results in more than 3 million patient visits each year to hospital and emergency care.⁵ Disease burden is amplified by the frequency and complexity of allergic reactions, which can escalate to anaphylaxis, emergency care and impact a patient’s wellbeing and participation in social activities. Collectively, food allergies cost US families an estimated $33 billion in 2024, underscoring the need for more effective and durable therapies.⁵

About RAPT Therapeutics

RAPT Therapeutics is a clinical-stage immunology-based biopharmaceutical company focused on discovering, developing and commercializing novel therapies for patients living with inflammatory and immunologic diseases. Utilizing deep and proprietary expertise in immunology, RAPT develops novel molecules that are designed to modulate the critical immune responses underlying these diseases.

About GSK

GSK is a global biopharma company with a purpose to unite science, technology, and talent to get ahead of disease together. Find out more at www.gsk.com.

Cautionary statement regarding forward-looking statements

GSK cautions investors that any forward-looking statements or projections made by GSK, including those made in this announcement, are subject to risks and uncertainties that may cause actual results to differ materially from those projected. Such factors include, but are not limited to, those described in the “Risk Factors” section in GSK’s Annual Report on Form 20-F for the year ended December 31, 2024. This communication includes forward-looking statements related to RAPT Therapeutics, ozureprubart and the acquisition of RAPT Therapeutics by GSK that are subject to risks, uncertainties and other factors. All statements other than statements of historical fact are statements that could be deemed forward-looking statements, including all statements regarding the intent, belief or current expectation of RAPT Therapeutics and members of its senior management team and can typically be identified by words such as “believe,” “expect,” “estimate,” “predict,” “target,” “potential,” “likely,” “continue,” “ongoing,” “could,” “should,” “intend,” “may,” “might,” “plan,” “seek,” “anticipate,” “project” and similar expressions, as well as variations or negatives of these words. Forward-looking statements include, without limitation, statements regarding the business combination, similar transactions, prospective performance, future plans, events, expectations, performance, objectives and opportunities and the outlook for RAPT Therapeutics’ business; the commercial success of RAPT Therapeutics’ products; the anticipated timing of clinical data and regulatory filings or approvals relating to products; the possibility of favourable or unfavourable results from clinical trials; the anticipated benefits of the acquisition; filings and approvals relating to the transaction; the expected timing of the completion of the transaction; the parties’ ability to complete the transaction; and the accuracy of any assumptions underlying any of the foregoing. Investors are cautioned that any such forward-looking statements are not guarantees of future performance and involve risks and uncertainties and are cautioned not to place undue reliance on these forward-looking statements. Actual results may differ materially from those currently anticipated due to a number of risks and uncertainties. Risks and uncertainties that could cause the actual results to differ from expectations contemplated by forward-looking statements include: uncertainties as to the timing of the tender offer and completion of the merger; the possibility that various closing conditions for the transaction may not be satisfied or waived, including that RAPT Therapeutics stockholders may not tender into the offer a majority of the shares of common stock outstanding at the time of the expiration of the offer or that required regulatory approvals may not be obtained or are obtained subject to conditions that are not anticipated; the occurrence of any event, change or other circumstance that could give rise to the termination of the merger agreement; the failure to realize anticipated benefits of the proposed acquisition when expected or at all; potential adverse reactions or changes to business relationships resulting from the proposed acquisition, including 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 that the proposed acquisition disrupts the current plans and operations of RAPT Therapeutics; transaction costs; risks associated with potential litigation or regulatory actions related to the transaction; and other risks and uncertainties described from time to time in documents filed with the SEC by RAPT Therapeutics, including current reports on Form 8-K, quarterly reports on Form 10-Q and annual reports on Form 10-K, as well as the Schedule 14D-9 to be filed by RAPT Therapeutics, or in GSK’s Annual Report on Form 20-F for the year ended December 31, 2024 filed with the SEC by GSK, as well as the Schedule TO to be filed by GSK. All forward- looking statements are based on information currently available to GSK and RAPT Therapeutics, and neither GSK nor RAPT Therapeutics assumes any obligation to update any forward-looking statements.

Media contact:
Email: corporate.media@gsk.com
Phone: +44 (0)20 8047 5502

SOURCE: GlaxoSmithKline plc