GSK just made its first big move under new boss Luke Miels—and it’s a chunky one. The FTSE 100 pharma giant is acquiring US biotech Rapt Therapeutics for $2.2bn (£1.6bn), nearly doubling the California firm’s share price overnight. Why the premium? GSK’s betting big on ozureprubart, Rapt’s experimental food allergy drug that could shake up a market with serious unmet needs. With trial data landing in 2026, this deal signals GSK’s appetite for high-potential pipeline assets. Here’s what you need to know.
What’s GSK Actually Buying?
At $58 per share—almost double Rapt’s $33.81 Nasdaq closing price—GSK’s paying $1.9bn upfront for global rights to ozureprubart, excluding mainland China, Hong Kong, Taiwan, and Macau. The drug targets inflammatory and immunologic diseases, specifically food allergies, where treatment options remain pretty thin on the ground.
Rapt specialises in therapies for immune-related conditions, and ozureprubart is their star asset. GSK’s chief scientific officer Tony Wood called it “another promising new, potential best-in-class treatment” that could deliver “sustained protection to patients.”
Deal’s expected to close in Q1 2026, assuming regulators don’t pump the brakes.
Why Food Allergies Matter Right Now
Food allergies affect millions globally, yet effective treatments remain scarce. Current options mostly involve strict avoidance and emergency interventions—hardly ideal for patients seeking normal lives.
Ozureprubart represents a different approach: sustained protection rather than reactive management. If trial data in 2026 proves positive, GSK could be sitting on a blockbuster in a market crying out for innovation.
Tony Wood emphasised the drug “addresses validated targets and where there is clear unmet medical need”—pharma speak for “this could actually help people and make money.”
Luke Miels Makes His Mark
This acquisition marks the first major deal for GSK’s new chief executive Luke Miels, who only recently took the reins. Starting with a $2.2bn bet sends a clear message: GSK’s hunting for high-impact pipeline additions, not playing it safe.
Rapt’s president and CEO Brian Wong noted the deal gives his company access to GSK’s “resources and infrastructure” plus “global development and commercialisation capabilities”—the muscle needed to take a promising drug to market worldwide.
Not everyone’s convinced yet. GSK shares dropped 1.24% to 1,793.49p following the announcement, suggesting investors want to see the trial data before celebrating.
The HIV Venture Reshuffle
In related news, GSK’s also reshuffling its HIV joint venture ViiV Healthcare. Japanese pharma Shionogi & Co is buying out Pfizer’s 11.7% stake for $2.1bn, boosting its own holding from 10% to 21.7%.
Pfizer’s walking away with $1.8bn whilst GSK maintains its 78.3% controlling stake. ViiV chair David Redfern called it a move to “simplify ViiV’s shareholder structure” whilst continuing collaboration with Shionogi on long-acting injectable HIV treatments.
Translation? Fewer cooks in the kitchen, cleaner ownership structure, same strategic direction.
What Happens Next
GSK now owns the rights to develop and commercialise ozureprubart globally (outside Greater China). They’ll also handle royalty payments owed to Rapt’s Chinese partner, Shanghai Jeyou Pharmaceutical Co.
Trial data expected in 2026 will determine whether this $2.2bn gamble pays off. Positive results could validate Miels’ aggressive start and position GSK as a leader in food allergy treatment. Disappointing data? That share price dip might look prophetic.
Either way, GSK’s signalling it’s back in acquisition mode—and willing to pay premiums for drugs with genuine market potential.
Key Takeaways
GSK’s $2.2bn acquisition of Rapt Therapeutics marks new CEO Luke Miels’ bold opening move, betting on an experimental food allergy drug with blockbuster potential. Trial data due in 2026 will determine if this premium gamble pays off.
FAQ
Q1: What is ozureprubart?
A: Ozureprubart is Rapt Therapeutics’ experimental drug designed to treat food allergies by providing sustained protection rather than just emergency intervention. Trial data is expected in 2026, which will determine its commercial viability.
Q2: Why did GSK pay nearly double Rapt’s share price?
A: GSK paid a premium because ozureprubart addresses a significant unmet medical need in food allergies, a market with few effective treatments. The potential for a best-in-class therapy justified the $58-per-share valuation versus the $33.81 closing price.
Q3: What territories does GSK’s acquisition cover?
A: GSK acquired global rights to ozureprubart excluding mainland China, Hong Kong, Taiwan, and Macau. Those territories remain with Rapt’s Chinese partner, Shanghai Jeyou Pharmaceutical Co.
Q4: Why did GSK shares fall after the announcement?
A: Shares dropped 1.24% as investors likely adopted a wait-and-see approach, wanting to review 2026 trial data before fully backing the $2.2bn investment. Premium acquisitions always carry risk until clinical proof emerges.
Q5: What’s happening with GSK’s HIV venture ViiV Healthcare?
A: Shionogi is buying Pfizer’s 11.7% stake in ViiV for $2.1bn, increasing its own holding to 21.7% whilst GSK retains 78.3%. This simplifies the ownership structure whilst maintaining the partnership’s focus on long-acting HIV treatments.
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Effective Date: 15th July 2025
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