GSK to acquire US-based biopharma company RAPT Therapeutics via a $2.2 billion deal — Details here

UK-based GSK Plc, on Tuesday, 20 January 2026, announced that the firm has signed a definitive agreement to potentially acquire the US-based biopharmaceutical company RAPT Therapeutics via a deal comprising an equity value of $2.2 billion, according to the official announcement.

The filing showed that the British biopharma company's acquisition moves come at a time when RAPT Therapeutics is focused on developing novel therapies for patients living with inflammatory and immunologic diseases.

“GSK Plc today announced that it has entered a definitive agreement to acquire RAPT Therapeutics, a California-based, clinical-stage biopharmaceutical company dedicated to developing novel therapies for patients living with inflammatory and immunologic diseases,” as per the press release.

According to the company, the acquisition transaction is expected to close by the end of the first quarter of calendar year 2026.

Acquisition details

As per the deal details, GSK is looking to pay an estimated aggregate equity value of $2.2 billion, giving shareholders $58 apiece at the closing price. The company also disclosed that the upfront investment will be $1.9 billion in the acquisition deal.

After GSK's acquisition, the company will take over the global rights to RAPT Therapeutics' ozureprubart programme, excluding the rights in 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,” the company said.

GSK's subsidiary will issue a tender offer to acquire all outstanding shares of RAPT common stock for $58 per share in cash within 10 business days of the signing.

Evercore is the financial advisor to the offer, while A&O Shearman is serving as legal counsel to GSK. J.P. Morgan Securities LLC and Cooley LLP are the financial advisor and legal counsel to RAPT Therapeutics, respectively.

“The addition of ozureprubart brings another promising new, potential best-in-class treatment to GSK’s pipeline. Food allergies cause severe health impacts to patients with existing treatment requiring injections as frequently as every 2 weeks. Ozureprubart offers the opportunity to bring sustained protection to patients with dosing every 12 weeks, and is consistent with our approach to acquire assets that address validated targets and where there is clear unmet medical need,” said Tony Wood, Chief Scientific Officer of GSK.

Stock movement

GSK stock at the London Stock Exchange was trading 0.96% lower at 1,798.50p (Great British Pence) during Tuesday's stock market session, compared to 1,816.00p at the previous market close, MarketWatch data shows.

Shares of GSK have given UK market investors more than 28% returns on their investment in the last five years and over 32% returns in the last one-year period.

However, on Wall Street, RAPT Therapeutics' stock jumped more than 63% to $57.41 during the premarket trading session on Nasdaq after the acquisition update, compared to $35.10 at the previous market close.

The US-based biopharma company's shares have risen 265% in the last one-year period but have lost over 79% in the last five years.

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