Novartis will acquire Excellergy, a young allergy drugmaker, to gain access to an experimental therapy that could improve upon the widely used medication Xolair.
The deal announced Friday could be worth as much as $2 billion overall when including the unspecified upfront payment as well as future payouts. It’s expected to close in the second half of the year, the companies said in a statement.
At the heart of the acquisition is a drug called Exl-111, which targets the antibody immunoglobulin E, or IgE. In certain cases, IgE can mistakenly react to substances — like food, pollen or pet dander — that wouldn’t otherwise be harmful. The antibody then binds to cells, triggering the release of histamines and in turn, an allergic reaction.
These IgE-mediated allergies can be treated with antihistamines as well as Xolair, a biologic drug co-marketed by Novartis and Roche which prevents IgE from locking onto cell receptors. But some people don’t respond to treatment, and its effects can take weeks to kick in.
Excellergy has claimed that Exl-111 could represent a therapeutic advance. It’s a multifunctional drug that can detach IgE from cells without triggering an immune response, while also possessing the capability to intercept and remove IgE before it reaches a cellular target. Exl-111 lowers the expression of an immune cell receptor that regulates allergic reactions, too, a combination of effects the company believes can lead to faster and better symptom control.
“It’s the holy grail of what people are trying to accomplish,” Geoff Harris, Excellergy’s chief scientific officer, told BioPharma Dive in October. “If you can turn off this access to the immune system, you can completely control a wide swath of different allergy-driven diseases.”
Excellergy officially launched in 2025 with $70 million in financing from Red Tree Venture Capital, Decheng Capital and Samsara BioCapital. Its portfolio is based on research from Stanford University and Switzerland’s University of Bern. The startup began testing Exl-111 in humans earlier this year and, in its statement, Novartis pointed to preclinical data and early results from that trial as evidence of a “differentiated profile.”
“This proposed acquisition strengthens our allergy portfolio and reflects our strategy of advancing innovative bold science to bring meaningful additional benefits to patients,” Fiona Marshall, Novartis’ president of biomedical research, said in a statement.
The acquisition is the latest in a series of dealmaking moves Novartis has made to help confront patent expirations from key drugs like Entresto and Cosentyx. Novartis has now purchased six companies since the start of 2025 and formed multiple partnerships focused on immune drug research. In September, the pharma reupped a pact with Monte Rosa Therapeutics. Three months later, it paid an AI-focused biotechnology company called Relation $55 million upfront in a bid to find new immune drug targets.