GSK Plc Announces Major Acquisition of US Biopharma Firm RAPT Therapeutics
British pharmaceutical leader GSK Plc made a significant announcement on Tuesday, 20 January 2026. The company revealed it has signed a definitive agreement to acquire RAPT Therapeutics, a clinical-stage biopharmaceutical company based in California. This strategic move involves an equity value of approximately $2.2 billion.
Deal Details and Financial Terms
According to the official press release, GSK will pay shareholders $58 per share in cash. The upfront investment in this acquisition deal totals $1.9 billion. GSK's subsidiary plans to issue a tender offer to purchase all outstanding shares of RAPT common stock within ten business days of signing the agreement.
Financial advisory firm Evercore is guiding GSK on this offer, while A&O Shearman provides legal counsel. For RAPT Therapeutics, J.P. Morgan Securities LLC serves as financial advisor, with Cooley LLP acting as legal counsel.
Strategic Focus on Inflammatory and Immunologic Diseases
RAPT Therapeutics specializes in developing novel therapies for patients suffering from inflammatory and immunologic diseases. Following the acquisition, GSK will obtain global rights to RAPT's ozureprubart programme, though rights in Mainland China, Macau, Taiwan, and Hong Kong are excluded.
GSK will also manage success-based milestone and royalty payments for ozureprubart owed to RAPT's partner, Shanghai Jeyou Pharmaceutical Co., Ltd.
Executive Perspective on the Acquisition
Tony Wood, Chief Scientific Officer of GSK, emphasized the strategic importance of this acquisition. He stated that ozureprubart represents a promising potential best-in-class treatment for GSK's pipeline.
"Food allergies cause severe health impacts to patients with existing treatment requiring injections as frequently as every 2 weeks," Wood explained. "Ozureprubart offers the opportunity to bring sustained protection to patients with dosing every 12 weeks. This acquisition aligns with our approach to acquire assets that address validated targets and clear unmet medical needs."
Stock Market Reaction
Market reactions to the announcement showed contrasting movements for both companies. On the London Stock Exchange, GSK stock traded 0.96% lower at 1,798.50p during Tuesday's session, down from 1,816.00p at the previous close.
Despite this short-term dip, GSK shares have delivered strong returns to UK market investors. Over the last five years, they have provided more than 28% returns, with over 32% returns in the past year alone.
In contrast, RAPT Therapeutics' stock surged dramatically on Wall Street. During premarket trading on Nasdaq, shares jumped more than 63% to $57.41, up from $35.10 at the previous market close.
The US biopharma company's shares have shown remarkable volatility. They have risen 265% in the last year but have lost over 79% in the past five years.
Timeline and Closing Expectations
GSK expects the transaction to close by the end of the first quarter of calendar year 2026. This acquisition represents a significant expansion of GSK's research and development capabilities in the critical area of inflammatory and immunologic diseases.
The move underscores the ongoing consolidation in the biopharmaceutical industry as major players seek to strengthen their pipelines through strategic acquisitions of innovative smaller companies.
