Announced as a milestone-based acquisition, Novartis’ purchase of Excellergy gives the company exposure to a next-generation IgE-targeting platform in a disease area it already understands. Novartis’ own IgE-focused drug—Xolair—treats moderate to severe allergy symptoms, including asthma, chronic hives, nasal polyps, and IgE-mediated food allergies. Xolair remains a major allergy asset, generating $1.7B for Novartis in 2025 and significant additional sales through Roche/Genentech in the U.S. IgE is the antibody that helps trigger allergic reactions by activating mast cells and basophils, immune cells that release histamines and drive inflammation. Xolair works by binding free IgE in the bloodstream before it attaches to these immune cells.