About Us

X4 Pharmaceuticals is developing novel therapeutics designed to improve immune cell trafficking and reverse immune suppression, which is fundamental to treating cancer and certain rare, genetic primary immunodeficiency diseases. Our oral, small molecule drug candidates inhibit the binding of chemokine CXCL12 to C-X-C receptor type 4 (CXCR4), a receptor-ligand pair that plays an essential role in normal immune surveillance. We are committed to advancing the fields of cancer immunotherapy and genetic immune disorders through innovation and investment in our proprietary clinical and preclinical pipeline.

X4’s lead product candidate, X4P-001-LD, a low dose formulation of X4P-001 is in a Phase 2/3 study in patients with WHIM syndrome, a rare genetic, primary immunodeficiency disease. X4P-001 is under Phase 1/2 testing in refractory clear cell renal cell carcinoma (ccRCC), melanoma, and other solid tumor indications.

Our third program, X4P-002, is in pre-clinical development and 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.