GSK plc (NYSE:GSK) on Tuesday agreed to acquire RAPT Therapeutics Inc. (NASDAQ:RAPT) for $58.00 per share.
The deal consideration is equivalent to an estimated aggregate equity value of $2.2 billion. Net of cash acquired, GSK’s estimated upfront investment is $1.9 billion.
RAPT Therapeutics is a California-based, clinical-stage biopharmaceutical company dedicated to developing novel therapies for inflammatory and immunologic diseases.
The acquisition includes ozureprubart, a long-acting anti-immunoglobulin E (IgE) monoclonal antibody, currently in phase 2b clinical development for prophylactic protection against food allergens.
IgE is a clinically validated target and is the only approved systemic therapy shown to protect patients from a harmful allergic and inflammatory immune response. Around 94% of severe food allergies are caused by IgE-mediated reactions.
Current anti-IgE treatment for food allergy involves injections every 2 to 4 weeks. Ozureprubart’s clinical profile offers the potential for less frequent dosing every 12 weeks, supporting improved compliance and patient outcomes, as well as providing a new option to approximately 25% of patients currently ineligible for existing therapy. Ozureprubart complements GSK’s extensive commercial footprint and prescriber base in allergy.
Data from the phase 2b trial (prestIgE) assessing the use of ozureprubart as monotherapy is expected in 2027, with phase 3 trials to be focused on both at-risk adult and paediatric populations.
Large and Growing Food Allergy Market
In the U.S., over 17 million people are diagnosed with food allergies, with more than 1.3 million people suffering severe reactions. More than 3 million patient visits each year to the hospital and emergency care.
The transaction gives GSK the global rights to the ozureprubart program, excluding mainland China, Macau, Taiwan, and Hong Kong. GSK will also be responsible for success-based milestone and royalty payments for ozureprubart owed to RAPT’s partner, Shanghai Jeyou Pharmaceutical Co., Ltd.
Management Commentary
Tony Wood, GSK’s chief scientific officer, said ozureprubart strengthens the company’s pipeline with a potential best-in-class allergy treatment, offering longer-lasting protection with quarterly dosing and addressing a clear unmet need in food allergy care.
RAPT Therapeutics CEO Brian Wong said the deal gives ozureprubart a clear path forward, pairing the program with GSK’s global development and commercial scale to unlock greater value for patients and shareholders.
Pfizer Exits ViiV Healthcare Stake
Concurrently, Pfizer Inc. (NYSE:PFE) agreed to exit its 11.7% investment in HIV drug developer, ViiV Healthcare.
With the transaction, Shionogi Co. Ltd.’s holding increases to 21.7%, and GSK maintains the 78.3% majority share.
ViiV Healthcare will issue new shares to Shionogi for $2.125 billion, and Pfizer will receive $1.875 billion.
GSK will receive a special dividend of $250 million, payable in GBP.
Shionogi will continue to have one Director position on the ViiV Healthcare Board, and will be represented by Dr John Keller, who has been a Director of ViiV Healthcare since 2012.
Both transactions are expected to close in the first quarter of 2026.
Price Action: RAPT Therapeutics shares were up 63.53% at $57.40 during premarket trading on Tuesday. The stock is trading at a new 52-week high, according to Benzinga Pro data. GSK shares were up 0.04%. Pfizer shares were down 0.51%.
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