Our grit drives solutions for patients. Every day, we strive to advance our pipeline of innovative medicines to treat rare diseases. By targeting the CXCR4 pathway, our novel medicines are designed to restore healthy immunity in patients with rare diseases.

Primary Immunodeficiency Diseases

Aberrant functioning of CXCR4 is associated with certain PI diseases. X4’s lead candidate, X4P-001, is initiating a Phase 3 registration trial for the PI disease, WHIM Syndrome.


X4 is developing and commercializing its best-in-class, oral medicines across a range of rare diseases, including primary immunodeficiency diseases and rare cancers, such as lymphomas.