Our product candidates are best-in-class, oral small molecule CXCR4 inhibitors. X4 is developing and commercializing our pipeline of CXCR4-targeted medicines for rare diseases, including primary immunodeficiency diseases and lymphomas.


X4’s core rare disease business strategy is to apply our CXCR4-targeted drug candidates to certain rare primary immunodeficiency (PI) diseases and lymphomas in which genetic mutations in CXCR4 create abnormal trafficking of white blood cells and play a role in disease processes. Our foremost clinical programs are for the treatment of the rare, genetic PI diseases, specifically WHIM syndrome and Severe Congenital Neutropenia, as well as for the genetically-driven lymphoma, Waldenstrom’s Macroglobulinemia.

* X4’s immuno-oncology clinical program for X4P-001 includes a clinical collaboration with Pfizer for Phase 1/2 in RCC. In addition, two successful oncology pilot studies in combination with checkpoint inhibitors have concluded: a Phase 1b biomarker study in melanoma and a Phase 1b in RCC.  X4’s strategy in immuno-oncology is focused on strategic collaborations and non-dilutive funding opportunities.