X4 Pharmaceuticals, Inc. is a clinical-stage biopharmaceutical company focused on the development of novel therapeutics for the treatment of rare diseases. The company's lead product candidate, mavorixafor, is a potential first-in-class, once-daily, oral inhibitor of CXCR4, currently in Phase 3 development for the treatment of WHIM syndrome, a rare, inherited, primary immunodeficiency disease caused by genetic mutations in the CXCR4 receptor gene. X4 Pharmaceuticals is also developing X4P-001, a potential first-in-class, oral, small molecule antagonist of CXCR2, currently in Phase 1 development for the treatment of severe congenital neutropenia (SCN), as well as several other preclinical programs.