GSK acquires Rapt Therapeutics for USD2.2B to advance long-acting food allergy treatments

UK—British pharmaceutical giant GSK has announced its acquisition of Rapt Therapeutics for USD2.2 billion, securing access to a promising antibody therapy designed to prevent severe food allergy reactions.

The deal centers on ozureprubart, an anti-immunoglobulin E (IgE) antibody that could transform how patients manage life-threatening food allergies.

GSK is offering USD58 per share for the Bay Area biotechnology company, representing a substantial 39% premium over Rapt’s closing stock price of USD35.10 on Friday, January 16.

The upfront investment, after accounting for cash acquired, totals approximately USD1.9 billion.

This transaction grants GSK worldwide rights to ozureprubart, excluding China, where the therapy remains under the ownership of Jemincare Pharmaceutical’s subsidiary.

From License to Blockbuster Potential

Rapt Therapeutics originally licensed ozureprubart from the Chinese pharmaceutical company Jemincare just one year ago.

While Jemincare had been testing the drug in phase 2 clinical trials for asthma and chronic spontaneous urticaria within China, Rapt moved quickly to advance the therapy into Western markets.

In October 2025, the company launched a phase 2b study across the United States, Canada, and Australia to evaluate ozureprubart as a preventive treatment for patients living with food allergies.

The therapy targets the same biological pathway as Xolair, the injectable IgE antibody inhibitor developed by Novartis and Roche.

Xolair made history in 2024 when the FDA approved it as the first medication to reduce allergic reactions to accidental exposure to certain foods.

However, Xolair requires patients to receive injections every two to four weeks, creating a significant treatment burden.

Extended Protection with Less Frequent Dosing

Rapt has positioned ozureprubart as a potential improvement over existing treatments, banking on the drug’s extended half-life to deliver comparable efficacy and safety with far less frequent administration.

Instead of requiring injections every few weeks, ozureprubart would only need to be administered once every 12 weeks.

This dosing schedule could dramatically improve quality of life for food allergy patients who require ongoing protection against potentially fatal reactions.

GSK Chief Scientific Officer Tony Wood emphasized the therapy’s potential in a January 20 statement.

“The addition of ozureprubart brings another promising new, potential best-in-class treatment to GSK’s pipeline,” Wood said.

He highlighted that food allergies create severe health impacts for patients, with current treatments demanding injections as frequently as every two 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,” Wood explained.

Clinical Development Timeline and Expansion Plans

The phase 2 study that Rapt initiated is expected to deliver results in 2027, according to GSK.

The pharmaceutical company has also indicated plans to launch a phase 3 clinical program, the final stage of testing required before seeking regulatory approval for commercial use.

Rapt CEO Brian Wong welcomed the acquisition, suggesting it provides an optimal path forward for the company’s development programs.

“This transaction has the potential to provide access to the global development and commercialization capabilities, resources and infrastructure that GSK has to offer and ultimately bring added value to our pipeline, patients and stockholders,” Wong stated.

Overcoming Past Development Setbacks

Rapt’s journey to this acquisition has not been without challenges.

The company faced significant difficulties in recent years, including two rounds of workforce reductions and the abandonment of its lead drug candidate, zelnecirnon.

The FDA placed phase 2 trials testing zelnecirnon for atopic dermatitis and asthma on clinical hold in February 2024 after a patient in the atopic dermatitis study experienced liver failure while taking the small-molecule CCR4 inhibitor.

This serious adverse event ultimately led Rapt to discontinue development of zelnecirnon and redirect its focus toward ozureprubart.

Beyond ozureprubart, Rapt maintains a pipeline that includes two additional CCR4 antagonists at various stages of development.

One remains in preclinical development for an undisclosed inflammatory condition, while the other, tivumecirnon, is being developed in partnership with Hanmi Pharmaceutical.

This partnered small molecule completed a phase 2 trial in 2024 for gastric cancer in combination with Merck’s cancer immunotherapy Keytruda.