X4 Pharmaceuticals, Inc. is a biopharmaceutical company dedicated to developing and commercializing targeted therapies for rare immune system diseases. The company's core scientific focus is on modulating the CXCR4 chemokine receptor pathway, which plays a critical role in immune cell trafficking and function. Its lead product, mavorixafor (marketed as XOLREMDI), is a first-in-class, oral, small-molecule CXCR4 antagonist. In April 2024, the U.S. FDA approved XOLREMDI for the treatment of WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis) syndrome in patients aged 12 and older. Beyond WHIM syndrome, X4 Pharmaceuticals is advancing mavorixafor in clinical trials for other indications, including chronic neutropenia, with a global Phase 3 trial currently underway. As a newly commercial-stage company, X4 generates revenue primarily through the commercialization of XOLREMDI in the United States, while also seeking regulatory approvals in Europe and other international markets. The company operates its corporate headquarters in Boston, Massachusetts, and maintains a research center of excellence in Vienna, Austria.
