At a Glance
- Company: Novartis AG; Excellergy Inc.
- Location: Basel, Switzerland (Novartis); Palo Alto, California (Excellergy)
- Deal value: Up to $2 billion in upfront and milestone payments
- Focus area: Exl-111, next-gen anti-IgE ECRI for allergic diseases
- Next steps: Close H2 2026; advance Exl-111 Phase 1; potential Phase 2 start 2027
What happened?
Novartis has agreed to acquire Excellergy Inc. in a deal worth up to $2 billion in upfront and milestone payments, announced on 27 March 2026. The deal comes just five months after the Palo Alto biotech emerged from stealth with $70 million in funding, representing a roughly 25x return for early backers including ARCH Venture Partners and RA Capital.
Why does it matter?
Xolair (omalizumab), the IgE-targeting antibody co-marketed by Novartis and Roche, generated $1.7 billion in Novartis sales in 2025, but biosimilar competition in the US is expected to arrive in the second half of 2026 as patents lapse. Exl-111 is designed to go beyond Xolair’s mechanism by directly disarming allergic effector cells at the source of activation, offering potentially faster and deeper suppression of IgE signalling, more convenient dosing, and a broader reach across IgE-mediated conditions including food allergy, chronic spontaneous urticaria, chronic inducible urticaria and allergic asthma.
Who’s behind it?
Excellergy was founded in 2021 with seed money from California-based Red Tree Venture Capital before completing its $70 million emergence round in late 2025. Novartis President of Biomedical Research Fiona Marshall described Exl-111 as “a differentiated next-generation anti-IgE programme that builds on biology Novartis knows well,” and CEO Todd Zavodnick of Excellergy said the deal “validates the transformative potential” of the company’s effector cell response inhibitor (ECRI) platform.
How was it achieved?
Exl-111 is a half-life extended, high-affinity anti-IgE antibody designed as a first-in-class ECRI that targets the IgE axis to actively dissociate cell-bound IgE from basophils and mast cells. Preclinical studies in non-human primates showed more than 99% removal of receptor-bound IgE from basophils, and a Phase 1 study launched last month.
What’s next?
The transaction is expected to close in the second half of 2026, subject to regulatory clearances. Under Novartis’ umbrella, Exl-111 will advance through Phase 1 with Phase 2 initiation targeted for 2027, aiming for a potential regulatory filing by around 2029–2030 to maintain Novartis’ leading position in IgE-mediated diseases as Xolair biosimilars erode its revenue base.
What are people saying?
Fiona Marshall (Novartis): “Adds a differentiated next-generation anti-IgE programme… potential to deliver faster and deeper suppression of IgE signalling.” Todd Zavodnick (Excellergy): “Novartis brings the global capabilities needed to realise its full potential.”