In a bold strategic opening to the 2026 fiscal year, pharmaceutical giant GSK (NYSE: GSK) has announced a definitive agreement to acquire RAPT Therapeutics (Nasdaq:RAPT) for approximately $2.2 billion. The deal, confirmed on January 20, 2026, represents a significant escalation in the multi-billion dollar race to dominate the food allergy treatment market, specifically targeting the convenience gap left by current industry standards.

The acquisition centers on RAPT’s lead asset, ozureprubart (formerly RPT904), a long-acting monoclonal antibody designed to neutralize immunoglobulin E (IgE), the primary driver of severe allergic reactions to foods such as peanuts, milk, and eggs. With the global food allergy market projected to surpass $9 billion by the mid-2030s, GSK’s move signals a shift away from traditional "allergen avoidance" toward long-term biological prevention, positioning the company as a direct challenger to the current market leader, Xolair.

A New Era for GSK’s Immunology Pipeline

The $2.2 billion transaction, valued at $58.00 per share in cash, marks the first major strategic initiative under GSK’s new CEO, Luke Miels, who took the helm on January 1, 2026. By paying a significant premium for the South San Francisco-based biotech, GSK is betting heavily on "convenience as a competitive advantage." While the existing standard of care, Xolair—co-marketed by Novartis (NYSE: NVS) and Roche (SIX:ROG)—requires injections every two to four weeks, RAPT’s ozureprubart is engineered for once-quarterly (every 12 weeks) dosing.

The timeline of this deal follows a turbulent few years for RAPT Therapeutics. The company’s stock suffered in late 2024 following an FDA clinical hold on a different asset, zelnecirnon, due to safety concerns. However, by mid-2025, RAPT had successfully pivoted its focus to the immunology-centric ozureprubart, which utilizes a different mechanism and has shown a cleaner safety profile in early trials. This strategic refocusing caught the eye of GSK, which has been aggressively scouting for "best-in-class" specialty medicines to bolster its Respiratory, Immunology & Inflammation (R&I) portfolio ahead of looming patent cliffs for its older blockbuster drugs.

The initial industry reaction has been overwhelmingly positive for RAPT shareholders, with the stock price surging over 70% in pre-market trading to meet the acquisition price. Analysts suggest that GSK’s existing commercial infrastructure, which already services thousands of allergists and respiratory specialists, makes them an ideal suitor to scale a specialized biologic like ozureprubart.

Winners and Losers in the Biologic Arms Race

The immediate winners of this deal are undoubtedly RAPT’s investors and the broader biotech sector, which has seen a resurgence of M&A activity in early 2026. However, the deal also serves as a defensive win for Sanofi (Nasdaq:SNY) and Regeneron (Nasdaq:REGN). While Sanofi and Regeneron's Dupixent is currently seeking expanded FDA approval for food allergies, the entry of GSK validates the high-value potential of the "biologic intervention" market, suggesting there is room for multiple multi-billion dollar players.

On the losing side of this development are Novartis and Roche. Their blockbuster drug, Xolair, enjoyed a virtual monopoly on systemic food allergy prophylaxis throughout 2024 and 2025. With GSK now entering the fray with a candidate that offers a fourfold improvement in dosing frequency, the "first-mover" advantage of Xolair is under threat. Furthermore, the timing of the acquisition coincides with the entry of omalizumab biosimilars in early 2026, which were already beginning to erode Xolair’s pricing power.

Additionally, the acquisition further sidelines the oral immunotherapy (OIT) market. Following the December 2025 announcement that Stallergenes Greer would discontinue the commercialization of the peanut-allergy drug Palforzia by July 2026, the market has decisively shifted toward biologics. Companies like DBV Technologies (Nasdaq:DBVT), which is preparing a 2026 BLA submission for its "Viaskin" peanut patch, now face a more formidable landscape where they must compete against the deep pockets and clinical expertise of a revitalized GSK.

Shifting Trends: From Avoidance to Intervention

The acquisition of RAPT fits into a broader industry trend where the management of chronic conditions is moving toward high-potency, long-acting biologics. In the food allergy space, this is particularly critical. For decades, the only solution for the 17 million Americans with food allergies was strict avoidance and the emergency use of epinephrine. The 2024 approval of Xolair for food allergies proved that patients and insurers are willing to pay for "peace of mind" treatments that prevent anaphylaxis before it starts.

GSK is also navigating a shifting regulatory environment. By targeting IgE—a clinically validated pathway—the company is reducing the "biological risk" of the acquisition. Unlike novel mechanisms that often fail in late-stage trials, the challenge for ozureprubart is purely pharmacological: proving that its long-acting formulation remains as effective as more frequent injections. This "validated target, superior delivery" strategy has become a hallmark of successful pharmaceutical M&A in the mid-2025s, mirroring similar strategies used by Merck & Co. (NYSE: MRK) in the immunology space.

The Road Ahead: 2027 and Beyond

The next 18 to 24 months will be a critical "de-risking" period for GSK. The deal is expected to close in the first quarter of 2026, after which GSK will take over the ongoing Phase IIb "prestIgE" clinical trial. Data from this study is expected in early 2027. If the results confirm that a once-every-12-weeks injection can provide the same protective "buffer" as Xolair, GSK will likely fast-track the asset for a 2030 or 2031 commercial launch.

However, challenges remain. GSK must ensure that ozureprubart can overcome the "BMI gap"—the segment of the population (roughly 25%) currently ineligible for Xolair because their body weight or baseline IgE levels are too high for the current dosing protocols. If GSK can prove efficacy in these underserved populations, ozureprubart could achieve "mega-blockbuster" status, potentially generating annual sales in excess of $3 billion.

Final Market Assessment

The GSK-RAPT deal is a defining moment for the food allergy market in 2026. It signals the end of the "wait-and-see" approach for large pharmaceutical firms and confirms that food allergy is now a top-tier therapeutic priority. For GSK, the $2.2 billion price tag is a calculated risk to ensure it is not left behind as the immunology market evolves toward more convenient, long-acting therapies.

For investors, the key metrics to watch in the coming months will be the integration of RAPT’s R&D team into GSK’s structure and any regulatory feedback regarding the Phase III trial design for ozureprubart. As the food allergy landscape moves from a single-player market to a crowded field of biologics and patches, convenience and patient adherence will be the primary drivers of commercial success.

This content is intended for informational purposes only and is not financial advice.