GSK has entered into a definitive agreement to acquire RAPT Therapeutics, a California-based clinical-stage biopharmaceutical company focused on innovative treatments for inflammatory and immunologic diseases. The transaction, valued at approximately USD 2.2 billion in equity, significantly expands GSK’s immunology portfolio.

The acquisition includes ozureprubart, a long-acting anti-immunoglobulin E (IgE) monoclonal antibody currently in phase IIb clinical development for the prevention of food allergy reactions. IgE is a well-established therapeutic target and is responsible for nearly 94 percent of severe food allergy cases.

Tony Wood, Chief Scientific Officer, GSK, said, “The acquisition aligns with the our strategy of targeting validated biological pathways with high unmet medical need, positioning ozureprubart as a potential best-in-class therapy for food allergy.”

Current anti-IgE therapies typically require injections every two to four weeks, posing a considerable treatment burden, particularly for paediatric patients. Ozureprubart has the potential to offer sustained protection with dosing every 12 weeks, improving patient adherence and outcomes, while also extending treatment access to around 25 percent of patients currently ineligible for existing therapies.

Data from the phase IIb prestIgE trial of ozureprubart monotherapy is expected in 2027, with phase III studies planned across both adult and paediatric populations. In the US alone, more than 17 million people live with food allergies, including over 1.3 million who experience severe reactions, leading to more than 3 million emergency and hospital visits annually.

Under the agreement, GSK will pay USD 58 per share in cash to RAPT shareholders, with an estimated upfront investment of USD 1.9 billion net of cash acquired. GSK will gain global rights to ozureprubart, excluding mainland China, Macau, Taiwan and Hong Kong, and will assume milestone and royalty obligations to RAPT’s partner, Shanghai Jeyou Pharmaceutical.

The transaction, subject to customary regulatory and shareholder approvals, is expected to close in the first quarter of 2026 and will be accounted for as a business combination by GSK.