Highlights

  • Rapt shares jumped after GSK agreed to acquire the company in cash
  • The offer price represented a premium exceeding 65% to prior close
  • Deal centers on Rapt’s phase 2 antibody therapy for food allergies

Shares of Rapt Therapeutics (NASDAQ:RAPT) climbed  64% on Tuesday to close at USD 57.57, following the announcement that the immunology-focused biotechnology company had agreed to be acquired by British pharmaceutical group GSK (NYSE: GSK). Under the terms of the agreement, GSK will acquire Rapt for approximately USD 2.2 bn in an all-cash deal. Rapt shareholders are set to receive USD 58.00 per share, representing a premium of more than 65% compared with the company’s closing price on January 16, the last trading session before the announcement.

The transaction will provide GSK with global rights to ozureprubart, Rapt’s experimental monoclonal antibody therapy, excluding mainland China, Macau, Taiwan, and Hong Kong. Ozureprubart is being developed as a treatment designed to protect against food allergens with less frequent dosing compared with currently available therapies. The drug candidate is currently undergoing phase 2 clinical trials.

In a statement accompanying the announcement, GSK’s Chief Scientific Officer Tony Wood said the addition of ozureprubart expands the company’s immunology pipeline with a potential new treatment option. The acquisition aligns with GSK’s broader focus on strengthening its research portfolio in areas with unmet medical needs.

The transaction is expected to close in the first quarter, subject to regulatory approvals and customary closing conditions. Until completion, Rapt will continue to operate as an independent entity.

Food allergies represent a significant public health issue, with more than 17 million people affected in the United States alone. Of these, an estimated 1.3 million individuals experience severe allergic reactions. Rapt’s investigational therapy targets a protein implicated in approximately 94% of severe food allergy responses, according to company disclosures.

Tuesday’s stock movement reflected the scale of the acquisition premium and the strategic relevance of Rapt’s clinical-stage asset within the immunology space.