GSK agreed on 20 January to acquire RAPT Therapeutics, a California-based clinical-stage biotech, for $58.00 per share in cash, giving the deal an equity value of approximately $2.2bn.
Why GSK plc is buying RAPT Therapeutics, Inc.
The purchase brings ozureprubart, a long-acting anti-immunoglobulin E monoclonal antibody in phase IIb development for prophylactic protection against food allergens. GSK said it could offer dosing every 12 weeks, compared with every two to four weeks for current anti-IgE treatments, and fits its existing allergy and immunology footprint.
“Ozureprubart offers the opportunity to bring sustained protection to patients with dosing every 12 weeks”
Deal terms and financing
GSK's upfront investment is about $1.9bn net of cash acquired. A GSK subsidiary launched a cash tender offer, with untendered shares to be acquired through a second-step merger at the same price. GSK also assumes success-based milestone and royalty payments owed to RAPT's partner, Shanghai Jeyou Pharmaceutical.
Regulatory approvals and timing
Closing required a majority of shares to be tendered and expiry of the US Hart-Scott-Rodino waiting period. GSK announced on 3 March 2026 that it had completed the acquisition.
Market context
Data from the phase IIb prestIgE trial are expected in 2027, with phase III studies planned in adults and children. Xolair, sold by Novartis and Roche, is the approved anti-IgE option; BioXconomy reported that about a quarter of patients are not eligible for current anti-IgE treatment.
