WHIM Syndrome


  • WHIM syndrome is a rare and difficult-to-diagnose primary immunodeficiency in which the body’s immune system does not function properly and has trouble fighting infections. Some doctors also call primary immunodeficiencies inborn errors of immunity, which are genetic mutations that cause immunodeficiencies.
  • WHIM syndrome is caused by mutations in the CXCR4 gene that cause white blood cells to get trapped in the bone marrow.
  • WHIM syndrome was named after four symptoms that most diagnosed patients have experienced: Warts, Hypogammaglobulinemia, Infections, Myelokathexis.
  • There are no existing treatments that specifically target the underlying causes of WHIM syndrome—new treatments are needed.
  • X4 Pharmaceuticals conducted a Phase 3 clinical trial (4WHIM) to help us learn if the investigational oral drug, mavorixafor, can help people with WHIM syndrome by targeting the way the disease works and if it can safely correct severe chronic neutropenia and lymphopenia, and reduce bacterial infections, warts and other aspects of the disease. In November 2022, the company announced positive top-line results from the 4WHIM clinical trial. For more information, you can read the press release announcement here. Additional data from the 4WHIM trial are expected to be announced in the first half of 2023.

Learn More: 

  • ClinicalTrials.gov –listing for the X4 study (NCT Identifier: 03995108) contains study sites and contact information
  • WHIMSyndrome.com—learn more about WHIM syndrome and find links to patient advocacy organizations on this site, sponsored by X4 Pharmaceuticals
  • Video—an illustrated video that shows how mavorixafor may work for people with WHIM syndrome

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