GlaxoSmithKline plc has agreed to acquire RAPT Therapeutics in a transaction valued at $2.2 billion, representing a 45% premium to RAPT’s closing share price prior to deal announcement. The all-cash offer will be financed through a combination of existing cash reserves and new debt facilities. The deal is expected to close in the second quarter of 2026, subject to customary regulatory approvals and RAPT shareholder consent. Post-closing, RAPT will become a wholly owned subsidiary of GSK, with its approximately 120 employees and research operations integrated into GSK’s Pharmaceuticals division.

The acquisition bolsters GSK’s respiratory and immunology portfolio by adding ozureprubart, RAPT’s Phase II monoclonal antibody targeting the IL-33 pathway. Ongoing proof-of-concept studies have shown a 60% reduction in asthma exacerbations versus placebo in moderate to severe patients. GSK projects peak annual sales of $1.2 billion for ozureprubart by 2030, complementing existing franchises such as Nucala and Trelegy. Management estimates the asset will expand GSK’s addressable respiratory immunology market by 15%, reinforcing its strategy to lead in inflammation biology.

GSK expects the transaction to be modestly accretive to adjusted earnings per share by 2028, after integration costs of approximately $150 million. Synergies are anticipated through combined R&D efforts, with an estimated $70 million annual run-rate savings by 2027 in shared clinical development and manufacturing. The deal will increase GSK’s net debt to EBITDA ratio by 0.2x, keeping leverage within the company’s target range of 1.5x–2.0x. GSK’s CFO has confirmed the acquisition aligns with the group’s capital allocation priorities, with no planned changes to the existing dividend policy.