X4 Pharmaceuticals, Inc. operates as a biotechnology company, which engages in developing human antibodies for treating infectious diseases. The company is headquartered in Boston, Massachusetts and currently employs 70 full-time employees. The company went IPO on 2017-11-16. The firm is focused on the discovery and development of therapies for people with diseases of the immune system. Its lead product candidate, mavorixafor, a small molecule antagonist of chemokine receptor C-X-C receptor type 4 (CXCR4), is being developed as an oral, once-daily therapy. Mavorixafor has the potential to provide therapeutic benefit across a variety of chronic neutropenic disorders, including warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) syndrome, a rare primary immunodeficiency. The company also has two pre-clinical candidates: X4P-003, a second-generation CXCR4 antagonist designed to have enhanced properties relative to mavorixafor, potentially enabling opportunities in CXCR4-dependent disorders and primary immunodeficiencies, and X4P-002, a CXCR4 antagonist with a distribution profile and a demonstrated ability to cross the blood-brain barrier.