X4 Pharmaceuticals’ (XFOR) Mavorixafor, proposed for the treatment of individuals aged 12 and older with WHIM syndrome, is under priority review by the FDA, with a decision expected on April 30, 2024. WHIM syndrome is a rare, primary immunodeficiency disease caused by genetic mutations in the CXCR4 receptor gene. It is characterized by four main symptoms: warts, low levels of certain antibodies, frequent infections, and myelokathexis. It is estimated that around 1,000 individuals in the United States are affected by WHIM syndrome. There are no approved treatments for this rare disease.XFOR is currently (Mar.28, 2024) trading at $1.37, down 2.84%.