Barzolvolimab

Barzolvolimab is an investigational monoclonal antibody directed at KIT, the receptor through which stem cell factor supports mast-cell development, survival, and activity. It blocks stem-cell-factor-dependent KIT signalling and is designed to reduce mast-cell numbers rather than to block a mediator after release.

An open-label study in chronic inducible urticaria measured skin mast cells by biopsy and serum tryptase after exposure to barzolvolimab. That makes the study more direct than a cell-culture experiment: people received the drug and investigators measured a human mast-cell effect. The population still did not have MCAS.

Published randomised studies and the current phase 3 programmes are in chronic spontaneous urticaria. The separate “mast-cell-mediated condition” tag records that precise middle ground: human mast-cell pharmacology in a relevant condition, without relabelling it as MCAS evidence or as a clonal mast cell disease.