About Us

X4 Pharmaceuticals is developing novel medicines designed to improve immune cell trafficking and restore healthy immunity in certain rare, genetic primary immunodeficiency diseases and lymphomas.

Our oral, small molecule therapeutics antagonize the C-X-C receptor type 4 (CXCR4) pathway which plays a central role in immune surveillance. We are leveraging our unique assets and understanding of the CXCR4 pathway to pursue a rare disease strategy for developing and commercializing new treatments for patients who lack effective treatment options.

X4’s most advanced product candidate, X4P-001, is in a Phase 2/3 clinical trial in patients with WHIM syndrome, a rare genetic, primary immunodeficiency disease. Clinical programs for X4P‑001 are also advancing in other rare, genetic immunodeficiency diseases, as well as in certain rare leukemias and lymphomas. Additional programs advancing in X4’s pipeline include another CXCR4 antagonist for primary immunodeficiencies, and a CXCR4-targeted candidate that crossed the blood-brain-barrier that is designed specifically for the treatment of brain cancers, including glioblastoma multiforme (GBM).

X4 was founded and is led by a team with deep product development and commercialization expertise, including several former members of the Genzyme leadership team, and is located in Cambridge, MA.