Calixis is developing a wild-type KIT inhibitor designed to deplete mast cells — the immune cells that drive chronic spontaneous urticaria and a range of allergic and inflammatory diseases.
Chronic spontaneous urticaria (CSU) causes unpredictable hives and swelling that can persist for years. Many patients continue to have symptoms despite antihistamines and existing therapies.
Across CSU and many other allergic and inflammatory conditions, the mast cell sits at the center of the pathology. We believe that reducing these cells at the source — rather than blocking one mediator at a time — could offer more complete and durable control.
See how our approach worksSignaling through the KIT receptor is essential for mast cells to develop and survive. Our oral small molecules are designed to shut down that signal.
We inhibit wild-type KIT — the form present in normal mast cells.
By removing KIT survival signaling, we aim to reduce the mast-cell population itself, addressing the source of mediator release rather than one downstream signal.
A convenient oral small molecule is intended to make treatment practical for chronic, long-term use across a broad patient population.
Chronic spontaneous urticaria is our first indication — chosen because its biology is clearly mast-cell driven. Because mast cells contribute to the pathology of many allergic and inflammatory conditions, we intend to advance our KIT-inhibition approach into additional diseases where depleting these cells could change outcomes.
Explore the platformRandomized, double-blind, placebo-controlled study of once-daily THB335 in adults who remain symptomatic despite antihistamines.
Read more →Financing from Atlas Venture, OrbiMed, and Aditum Bio will advance the company's pipeline of oral mast-cell–targeted therapies.
Read more →We welcome inquiries from investigators, potential partners, investors, and members of the patient community.
Calixis's investigational compounds have not been approved by the U.S. Food and Drug Administration or any other regulatory authority. Their safety and efficacy have not been established. This website is intended for general informational purposes only and is not medical advice.
