GSK has entered into an agreement to acquire RAPT Therapeutics for $2.2 billion

On January 20, GSK plc (LSE/NYSE: GSK) announced that it has entered a definitive agreement to acquire RAPT Therapeutics (“RAPT”) (NASDAQ: RAPT), a California-based, clinical-stage biopharmaceutical company dedicated to developing novel therapies for patients living with inflammatory and immunologic diseases. 

The acquisition includes ozureprubart, a long-acting anti-immunoglobulin E (IgE) monoclonal antibody, currently in phase IIb clinical development for prophylactic protection against food allergens.   

IgE is a clinically validated target and is the only approved systemic therapy shown to protect patients from a harmful allergic and inflammatory immune response. Around 94% of severe food allergies are caused by IgE-mediated reactions.

Data from the Phase IIb trial (pretigE) evaluating ozureprubart as a monotherapy is expected to be released in 2027, with the Phase III trial focusing on high-risk adult and pediatric populations.

Under the terms of the agreement, GSK will pay RAPT Therapeutics shareholders $58.00 per share at closing for an estimated aggregate equity value of $2.2 billion. Net of cash acquired, GSK's estimated upfront investment is $1.9 billion.

GSK will also be responsible for paying Jeyou Pharma, the partner of RAPT Therapeutics, success milestones and royalties for ozureprubart. In December 2024, RAPT Therapeutics licensed the overseas rights to the IgE monoclonal antibody JYB1904 (RPT904) from Jeyou Pharma. As part of the agreement, Jeyou Pharma received an upfront payment of $35 million and is eligible to receive up to $672.5 million in additional payments upon achieving various regulatory and commercial milestones, along with future royalties on sales of RPT904 in the licensed territories.

Tony Wood, Chief Scientific Officer, GSK said: "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."