Excellergy

Excellergy is a clinical-stage biotechnology company developing a portfolio of first-in-class trifunctional effector cell response inhibitors (ECRIs) to treat severe allergic diseases. The company was seeded in 2021 by Red Tree Venture Capital and is headquartered in Palo Alto, California. In October 2025, Excellergy publicly launched with $70 million in Series A financing led by Samsara BioCapital, with co-investments from Red Tree Venture Capital and Decheng Capital.

The company's therapeutic approach is built upon scientific advances from Stanford University and the University of Bern related to the structural binding of Immunoglobulin E (IgE) to its receptor. Excellergy is led by President and CEO Todd Zavodnick, a biotech veteran, alongside Co-founder and Chief Scientific Officer Geoffrey Harris, DVM, PhD, and Chief Medical Officer Philip M. Brown, MD, JD. Other scientific co-founders include Professor Alexander Eggel of the University of Bern, Professor Ted Jardetzky of Stanford University, and Luke Pennington, who is the company's Vice President of Discovery.

Excellergy's ECRIs represent a new therapeutic category designed to provide more complete control of allergic disease compared to existing treatments. The technology employs a trifunctional mechanism that: 1) rapidly removes IgE already bound to effector cells (mast cells and basophils) without triggering cell activation, 2) neutralizes free IgE, and 3) accelerates the downregulation of the IgE receptor FcεRI. This multi-pronged attack on the IgE pathway aims to shut down the allergic response at its source, offering the potential for faster onset and more comprehensive control for a broader patient population. Pre-clinical data has supported this mechanism, with the findings published in the Journal of Allergy and Clinical Immunology. The company's business model is focused on advancing its portfolio of ECRIs through clinical development to address multi-billion-dollar opportunities across a wide range of allergic conditions, such as food allergies, chronic spontaneous urticaria, asthma, and atopic dermatitis. The recent funding is intended to support the advancement of its lead asset into first-in-human clinical studies, which are planned to begin in early 2026.

Keywords: effector cell response inhibitors, ECRI, allergy therapeutics, Immunoglobulin E, IgE biology, anti-IgE, mast cells, basophils, FceRI receptor, trifunctional inhibitors, allergic disease, severe allergies, clinical-stage biotech, biopharmaceutical, immunology, monoclonal antibodies, venture capital, Samsara BioCapital, Red Tree Venture Capital, Decheng Capital, food allergy, chronic spontaneous urticaria, asthma, atopic dermatitis, anaphylaxis