GSK, the UK’s second-biggest drugmaker, has unveiled a $2.2bn (£1.6bn) deal to acquire a Californian biotech company which is developing a drug to protect against severe food allergies, including allergies to nuts, milk and eggs.

It is the first large deal announced by GSK’s new chief executive, Luke Miels, who joined the London-based company in 2017 as chief commercial officer and took the reins from Emma Walmsley at the start of the year.

RAPT Therapeutics is developing therapies for people with inflammatory and immunologic diseases. Its main medication is ozureprubart (Ozu), a long-acting treatment against food allergies in children and adults that is in mid-stage clinical trials in the US. It is designed to bind to and neutralise IgE, an underlying driver of food allergy reactions.

Ozu is being tested on people with allergies to peanut, milk, egg, cashew or walnut. Data from the trial is expected next year, and late-stage clinical studies starting in the second half of 2027 will be focused on children and adults who are at risk.

If the drug is successful in those trials, it could be launched in 2031, and is seen as a potential “blockbuster” drug – with annual sales of at least $1bn – for GSK, which is targeting total revenues of £40bn by that year.

Current treatment for food allergies can involve injections every two to four weeks, which can be a significant burden, especially since most patients are children. Ozu is given every 12 weeks, and could be a new option for the 25% of patients who are currently ineligible for existing therapy.

At the moment, Novartis’s Xolair – whose US sales are set to grow to more than $1.5bn this year – is the only FDA-approved antibody designed to target and block IgE.

In the US, more than 17 million people are diagnosed with food allergies, and more than 1.3 million people suffer severe reactions, resulting in more than 3m trips each year to hospital and emergency care.

About 6% of UK adults – 2.4 million people – have a food allergy, according to the Food Standards Agency. Peanuts and tree nuts such as hazelnuts, walnuts and almonds are most likely to cause an allergic reaction. Allergies to milk, fish and seafood are less common. Childhood food allergies persist into early adulthood, while about half of food allergies develop in later adulthood.

Tony Wood, the GSK chief scientific officer, 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.”

GSK is paying RAPT shareholders $58 a share. The Nasdaq-listed shares jumped by 63% to $57.40 in pre-market trading, while GSK’s shares dropped by 1.5%.

The acquisition gives GSK the global rights to ozureprubart, excluding mainland China, Macau, Taiwan and Hong Kong.