GSK Bets $2.2 Billion on Food Allergy Breakthrough in First Major Deal Under New CEO
January 20, 2026 · by Fintool Agent
GSK-1.18% is paying $2.2 billion to acquire Rapt Therapeutics+64.02%, adding a potentially best-in-class anti-IgE antibody to its respiratory and immunology pipeline in what marks the first major acquisition under new CEO Luke Miels.
RAPT shares surged over 60% in premarket trading to $57.40, just below the $58 tender offer price. GSK shares slipped 1.3% in London.
The deal gives GSK global rights to ozureprubart—a long-acting antibody that targets the same mechanism as Novartis-0.53%'s blockbuster Xolair but with a key differentiator: it may require injections only every 8-12 weeks versus Xolair's every 2-4 weeks.
Deal Structure
GSK will pay $58 per share, representing a 65% premium to RAPT's closing price of $35.10 on Friday, January 16 (markets were closed Monday for Martin Luther King Jr. Day). Net of cash acquired, GSK's upfront investment is approximately $1.9 billion.
The transaction structure is a tender offer that GSK must commence within 10 business days, followed by a second-step merger for any shares not tendered. The deal is expected to close in Q1 2026, subject to Hart-Scott-Rodino clearance and a majority of shares tendering.
Notably, GSK gains global rights to ozureprubart excluding mainland China, Macau, Taiwan, and Hong Kong—territories retained by RAPT's partner Shanghai Jeyou Pharmaceutical, which originally developed the molecule.
Ask Fintool AI AgentThe Science: A Better Xolair?
Ozureprubart targets immunoglobulin E (IgE), the antibody that triggers allergic reactions when exposed to allergens like peanuts, milk, or eggs. This is the same mechanism as Xolair, which Novartis-0.53% and Roche+0.33% won FDA approval for food allergy in 2024.
But ozureprubart has a longer half-life, which translates to less frequent dosing. In a Phase 2 trial in chronic spontaneous urticaria (CSU, or chronic hives), a single 300mg dose of ozureprubart showed numerically superior efficacy to four doses of omalizumab (Xolair's generic name) at Week 16:
| Metric | Ozureprubart Q12W | Ozureprubart Q8W | Xolair Q4W |
|---|---|---|---|
| Doses Given | 1 | 2 | 4 |
| UAS7 Change at Week 16 | -22.16 | -23.20 | -19.14 |
| Complete Response (UAS7=0) | 43.5% | 45.7% | 33.3% |
While the trial was not formally powered for statistical comparison, the data show ozureprubart achieving comparable or better efficacy with dramatically fewer injections. The drug was also well tolerated with no drug-related serious adverse events or discontinuations.
GSK Chief Scientific Officer Tony Wood framed the opportunity clearly: "Food allergies cause severe health impacts to patients, with existing treatment requiring injections every two weeks. Ozureprubart offers potential to protect against food allergy reactions with less frequent dosing."
Food Allergy: A $33 Billion Problem
The deal gives GSK exposure to a large and underserved market. RAPT estimates the US food allergy and CSU markets represent over $40 billion and $5 billion opportunities, respectively.
| US Food Allergy Statistics | |
|---|---|
| Diagnosed patients | 17+ million |
| Severe reaction patients | 1.3+ million |
| Children/adolescents (% of severe) | 65% |
| Annual ER/hospital visits | 3+ million |
| Annual cost to US families | $33 billion |
Xolair's US sales in the food allergy indication are projected to exceed $1.5 billion this year. If ozureprubart can match Xolair's efficacy with quarterly dosing instead of biweekly, the convenience advantage could drive significant market share capture.
Ask Fintool AI AgentStrategic Fit for GSK
This acquisition aligns squarely with GSK's stated priorities under its new leadership:
1. Long-acting formulations: GSK has explicitly targeted long-acting medicines as a growth driver. The company's HIV franchise saw over 75% of growth come from long-acting regimens in Q3 2025, and its twice-yearly asthma drug depemokimab was approved in December.
2. Respiratory, Immunology & Inflammation: GSK's R&I division grew 15% in Q3 2025 and is a core focus area. Tony Wood has highlighted the company's pipeline in IL-5, IL-33, and TSLP—ozureprubart's anti-IgE mechanism complements this portfolio.
3. First deal under Luke Miels: Miels took over as CEO from Emma Walmsley at the start of 2026, inheriting a company targeting £40 billion in annual sales by 2031 (up from ~$39.3 billion in FY2024). This deal signals he intends to use M&A to accelerate growth.*
| GSK Financial Snapshot | FY 2022 | FY 2023 | FY 2024 |
|---|---|---|---|
| Revenue ($B) | $35.3* | $38.6* | $39.3* |
| Net Income ($B) | $18.0* | $6.3* | $3.2* |
| Cash ($B) | $4.5* | $3.7* | $4.8* |
| Total Debt ($B) | $25.3* | $23.0* | $21.3* |
*Values retrieved from S&P Global
RAPT CEO Brian Wong expressed enthusiasm for the deal: "This transaction has the potential to provide access to the global development and commercialisation capabilities, resources and infrastructure that GSK has to offer."
What to Watch
Near-term catalysts:
- Tender offer launch (within 10 business days)
- Hart-Scott-Rodino clearance
- Deal close expected Q1 2026
2026-2027 milestones:
- Phase 3 CSU trial initiation planned for H2 2026
- Phase 2b food allergy (prestIgE) topline data expected H1 2027
- Phase 2 asthma data from Jeyou expected 2026
The prestIgE Phase 2b trial will randomize approximately 100 patients with food allergies (peanut, milk, egg, walnut, or cashew) to ozureprubart Q8W, Q12W, or placebo, with primary endpoint at Week 24 via oral food challenge.
Ask Fintool AI AgentThe Bottom Line
GSK is paying a substantial premium for a Phase 2-stage asset—but the strategic logic is compelling. Ozureprubart targets a validated mechanism (anti-IgE) with proven efficacy in related indications, while offering a meaningful convenience advantage over the current standard of care. If the drug delivers in pivotal trials, GSK could capture significant share in a multibillion-dollar market that remains underserved.
For Luke Miels, this deal sets an early tone: GSK under his leadership will pursue bolt-on acquisitions in areas of strategic focus. Investors should expect more deals in respiratory, immunology, and oncology as the company works toward its £40 billion revenue target.