Progress 4 Patients

At X4, we are driven to successfully advance innovative therapeutics that truly make a difference in the lives of people with rare immunodeficiencies and few or no treatment options.

What’s it Like Living with Chronic Neutropenia?

What’s it Like Living with WHIM Syndrome?

Our Clinical Trials

Chronic Neutropenic Disorders

  • Chronic neutropenia is a rare blood condition defined by a decrease in blood neutrophil counts lasting more than three months; people with chronic neutropenia are at higher risk of developing infections and certain cancers and having a reduced quality of life.
  • Following successful completion of Phase 1b and Phase 2 clinical trials exploring the use of once-daily oral mavorixafor in the treatment of certain chronic neutropenic disorders, we are poised to begin a pivotal, global Phase 3 clinical trial.
  • The Phase 3 4WARD trial (NCT06056297) aims to evaluate the efficacy, safety, and tolerability of oral once-daily mavorixafor (with or without G-CSF) in people with congenital or acquired primary autoimmune and idiopathic chronic neutropenia who are experiencing recurrent and/or serious infections. For more information, please visit
4WARD Logo and Website Link

Community and Care Resources

WHIM Syndrome Community

Private Facebook group for people living with WHIM Syndrome. Search under Groups for WHIM Syndrome Community

Immune Deficiency Foundation

The Immune Deficiency Foundation (IDF)

Not-for-profit patient advocacy organization that provides information and resources for people with primary immunodeficiencies (PIs)

International Patient Organization for Primary Immunodeficiencies (IPOPI)

IPOPI is an international not-for-profit organization that advocates for people with primary immunodeficiencies worldwide

Jeffrey Modell Foundation

The Jeffrey Modell Foundation (JMF)

Not-for-profit organization devoted to early and precise diagnosis, meaningful treatments and ultimately cures for people with primary immunodeficiencies.

National Neutropenia Network (NNN)

Not-for-profit organization that promotes awareness, education and research for people with severe chronic neutropenia and their families

national neutropenia network
National Organization for Rare Disorders

National Organization for Rare Disorders (NORD)

A not-for-profit patient advocacy organization dedicated to improving the lives of people living with rare diseases and the organizations that serve them