A Study of Mavorixafor in Participants With Congenital and Acquired Primary Autoimmune and Idiopathic Chronic Neutropenic Disorders Who Are Experiencing Recurrent and/or Serious Infections

August 4, 2026 updated by: X4 Pharmaceuticals

A Phase 3, Randomized, Double-blind, Placebo-controlled, Multicenter Study of Mavorixafor in Participants With Congenital and Acquired Primary Autoimmune and Idiopathic Chronic Neutropenic Disorders Who Are Experiencing Recurrent and/or Serious Infections

The purpose of this study is to demonstrate the efficacy and evaluate the safety and tolerability of mavorixafor in participants with congenital or acquired primary autoimmune and idiopathic chronic neutropenic disorders who are experiencing recurrent and/or serious infections as assessed by demonstrating its clinical benefit and increasing levels of circulating neutrophils.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

All participants will continue their pre-study background therapy, defined as the participant's current treatment regimen. Options include, but are not limited to, granulocyte-colony stimulating factor (G-CSF), immunoglobulin replacement therapy, prophylactic antibiotics, or "watchful waiting".

Study Type

Interventional

Enrollment (Estimated)

176

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Argentina
      • Buenos Aires, Argentina, B1888AAE
        • Recruiting
        • Hospital El Cruce
      • Córdoba, Argentina, X5000AAW
        • Recruiting
        • Instituto de Investigaciones Clínicas Córdoba
      • San Miguel de Tucumán, Argentina, T4000IIH
        • Recruiting
        • Santorio 9 de Julio
  • Australia
      • Nedlands, Australia, 6009
        • Recruiting
        • Perth Children's Hospital
      • Southport, Australia, 4215
        • Recruiting
        • ICON Cancer Centre Southport
      • Wendouree, Australia, 3355
        • Recruiting
        • Ballarat Oncology And Haematology Services
  • Belgium
      • Leuven, Belgium, 3000
        • Recruiting
        • Universitair Ziekenhuis Leuven
  • Canada
      • Edmonton, Canada, AB T6G 2R3
        • Recruiting
        • University of Alberta Hospital
      • Vancouver, Canada, V5Z 4H4
        • Recruiting
        • BC Children's Hospital
  • Colombia
      • Cali, Colombia, 76004
        • Recruiting
        • Clinica IMBANACO S.A.S
      • Chapinero, Colombia, 0813
        • Recruiting
        • Clinica del Country
      • Medellín, Colombia, 500034
        • Recruiting
        • Hospital Pablo Tobon Uribe
    • Santander Department
      • Floridablanca, Santander Department, Colombia, 681003
        • Recruiting
        • Fundacion Cardiovascular de Colombia-Instituto del Corazon Florida Blanca
  • Czechia
      • Brno, Czechia, 62500
        • Recruiting
        • The University Hospital Brno
      • Prague, Czechia, 15006
        • Recruiting
        • Motol University Hospital
  • France
      • Lyon, France, 69008
        • Recruiting
        • Institute of Hematology and Pediatric Oncology - Lyon
      • Paris, France, 75010
        • Recruiting
        • Hopital Saint Louis
      • Paris, France, 75012
        • Recruiting
        • Hospital Armand Trousseau Ap-Hp
      • Paris, France, 75015
        • Recruiting
        • Hôpital Necker - Enfants Malade
      • Rennes, France, 75033
        • Recruiting
        • Centre Hospitalier Universitaire de Rennes
      • Toulouse, France, 31059
        • Recruiting
        • Institut Universitaire de Cancérologie de Toulouse - Oncopôle
  • Georgia
      • Tbilisi, Georgia, 112
        • Recruiting
        • LTD "Israeli-Georgian Medical Research Clinic Healthycore"
      • Tbilisi, Georgia, 141
        • Recruiting
        • LEPL The First University Clinic of Tbilisi State Medical University
      • Tbilisi, Georgia, 159
        • Recruiting
        • JSC K. Eristavi National Center of Experimental and Clinical Surgery
      • Tbilisi, Georgia, 186
        • Recruiting
        • LTD Multiprofile Clinic Concilium Medulla
  • Germany
      • Dresden, Germany, 01307
        • Recruiting
        • Universitaetsklinikum Carl Gustav Carus TU Dresden
      • Dresden, Germany, 01307
        • Recruiting
        • Klinik und Poliklinik fur Kinder- und Jugendmedizin, Universitatsklinikum Carl Gustav Carus an der TU
  • Greece
      • Athens, Greece, 10177
        • Recruiting
        • Hellenic Airforce 251 General Hospital
      • Heraklion, Greece, 71500
        • Recruiting
        • University General Hospital of Heraklion
      • Pátrai, Greece, 26443
        • Recruiting
        • The Olympion Private General Clinic
      • Thessaloniki, Greece, 54636
        • Recruiting
        • AHEPA General Hospital of Thessaloniki
  • Hungary
      • Budapest, Hungary, 1085
        • Recruiting
        • Semmelweis University
      • Budapest, Hungary, 1012
        • Recruiting
        • CMC Deli Klinika
      • Szombathely, Hungary, 9700
        • Recruiting
        • Teaching Hospital Markusovszky
  • India
    • Bihar
      • Patna, Bihar, India, 800014
        • Withdrawn
        • Indira Gandhi Institute of Medical Sciences
    • Gujarat
      • Surat, Gujarat, India, 395002
        • Withdrawn
        • Nirmal Hospital Private Limited
    • Rajasthan
      • Udaipur, Rajasthan, India, 313001
        • Withdrawn
        • Pacific Medical College and Hospital
    • Telangana
      • Hyderabad, Telangana, India, 500084
        • Terminated
        • Yashoda Hospital
  • Israel
      • Haifa, Israel, 3109601
        • Recruiting
        • Ruth Rappaport Children's Hospital, Rambam Health Corporation
      • Jerusalem, Israel, 9112001
        • Recruiting
        • Hadassah University Hospital-ein Kerem
      • Petah Tikva, Israel, 4920235
        • Recruiting
        • Schneider Children's Medical Center of Israel
      • Ramat Gan, Israel, 5265601
        • Recruiting
        • The Chaim Sheba Medical Center
  • Italy
      • Brescia, Italy, 25121
        • Recruiting
        • ASST Spedali Civili di Brescia
      • Genova, Italy, 16147
        • Recruiting
        • IRCCS Instituto G. Gaslini
      • Meldola, Italy, 47014
        • Recruiting
        • Istituto Scientifico Romagnolo Per Lo Studio E La Cura Dei Tumori (IRST) Dino Amadori
      • Monza, Italy, 20900
        • Recruiting
        • IRCCS San Gerardo dei Tintori
      • Roma, Italy, PC 00165
        • Recruiting
        • Bambino Gesu Children's Hospital
      • Torino, Italy, 10126
        • Recruiting
        • AOU Città della Salute e della Scienza di Torino
    • Ancona
      • Torrette, Ancona, Italy, 60126
        • Recruiting
        • A. O. U. delle Marche
  • Malaysia
      • Kuala Lumpur, Malaysia, 56000
        • Recruiting
        • Hospital Pakar Kanak-Kanak UKM
  • Portugal
      • Aveiro, Portugal, 3810-164
        • Recruiting
        • Unidade Local de Saúde da Região de Aveiro
      • Coimbra, Portugal, 3000-602
        • Recruiting
        • Unidade Local de Saude Coimbra - Paediatric Hospital
      • Coimbra, Portugal, 3041-801
        • Recruiting
        • Unidade Local de Saude Coimbra - Quinta dos Vales
      • Lisbon, Portugal, 1649-028
        • Recruiting
        • Unidade Local de Saúde Santa Maria
  • Romania
      • Bucharest, Romania, 022328
        • Recruiting
        • Institutul Clinic Fundeni
      • Bucharest, Romania, 22328
        • Recruiting
        • Institutul Clinic Fundeni
      • Bucharest, Romania, 020125
        • Recruiting
        • Spitalul Clinic Colentina Site 1
      • Bucharest, Romania, 020125
        • Recruiting
        • Spitalul Clinic Colentina Site 2
      • Târgu Mureş, Romania, 540136
        • Recruiting
        • Spitalul Clinic Județean de Urgență
  • Serbia
      • Belgrade, Serbia, 11000
        • Recruiting
        • University Clinical Centre of Serbia
  • Spain
      • Barcelona, Spain, PC08003
        • Recruiting
        • Hospital del Mar
      • Barcelona, Spain, PC 08916
        • Recruiting
        • ICO Badalona - Institut Català d'Oncologia
      • Cáceres, Spain, 10003
        • Recruiting
        • Hospital San Pedro de Alcantara
      • Córdoba, Spain, 14004
        • Withdrawn
        • Hospital Universitario Reina Sofia
      • Las Palmas de Gran Canaria, Spain, 35010
        • Recruiting
        • Hospital Universitario de Gran Canaria Doctor Negrín
      • Madrid, Spain, 28040
        • Recruiting
        • Hospital Universitario Fundacion Jimenez Diaz
      • Madrid, Spain, 28006
        • Recruiting
        • Hospital de la Princesa
      • Madrid, Spain, 28031
        • Withdrawn
        • Hospital Universitario Infanta Leonor
      • Santander, Spain, 39008
        • Recruiting
        • Hospital Universitario Marques de Valdecilla
      • Seville, Spain, 41013
        • Recruiting
        • Hospital Universitario Virgen del Rocio
      • Valencia, Spain, 46026
        • Recruiting
        • Hospital Universitario y Politécnico de La Fe
  • Switzerland
      • Bern, Switzerland, 3010
        • Recruiting
        • Inselspital - University Hospital Bern Site 1
      • Bern, Switzerland, 3010
        • Recruiting
        • Inselspital - University Hospital Bern Site 2
  • Thailand
      • Bangkok, Thailand, 10700
        • Recruiting
        • Siriraj Hospital
      • Bangkok, Thailand, 10400
        • Recruiting
        • Ramathibodi Hospital
  • Turkey (Türkiye)
      • Ankara, Turkey (Türkiye), 6000
        • Recruiting
        • Dr. Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital
      • Ankara, Turkey (Türkiye), 6620
        • Recruiting
        • Ankara University School of Medicine
      • Nilufer, Turkey (Türkiye)
        • Recruiting
        • Uludag University Faculty Of Medicine
      • Samsun, Turkey (Türkiye), 55200
        • Recruiting
        • Ondokuz Mayis University Medical Faculty Hospital
    • Süleymanpaşa
      • Tekirdağ, Süleymanpaşa, Turkey (Türkiye), 59030
        • Recruiting
        • Namik Kemal University (Tekirdağ Namık Kemal Üniversitesi)
  • Ukraine
      • Kyiv, Ukraine, 03151
        • Recruiting
        • Medical Center Dobrobut-Clinic LLC
      • Kyiv, Ukraine, 2091
        • Recruiting
        • Medical Center Ok Clinic of International Institute of Clinical Research LLC
      • Kyiv, Ukraine, 3022
        • Recruiting
        • Llc Onto-Med
      • Ternopil, Ukraine, 46000
        • Recruiting
        • Communal non-commercial enterprise "Ternopil City Children's Communal Hospital"
      • Ternopil, Ukraine, 46002
        • Recruiting
        • Medical Center The Clinic of Hospodarskyy LLC
    • Oblast
      • Lviv, Oblast, Ukraine, 79010
        • Recruiting
        • Lviv Regional Clinical Diagnostic Centre
  • United Kingdom
      • Cardiff, United Kingdom, CF14 4XW
        • Recruiting
        • University Hospital of Wales
      • London, United Kingdom, W12 0HS
        • Recruiting
        • Imperial College Healthcare NHS Trust - Hammersmith Hospital
      • London, United Kingdom, SE5 9RS
        • Recruiting
        • King's College Hospital
      • London, United Kingdom, NW3 2QG
        • Recruiting
        • Royal Free London Nhs Foundation Trust Royal Free Hospital
      • London, United Kingdom, CF14 4XW
        • Recruiting
        • Cardiff and Vale University Health Board
      • London, United Kingdom, WC1N 1DZ
        • Recruiting
        • Great Ormond Street Hospital for Children NHS Trust
  • United States
    • Arizona
      • Phoenix, Arizona, United States, 85016
        • Recruiting
        • Phoenix Children's Hospital
    • California
      • Irvine, California, United States, 92697
        • Recruiting
        • UC Irvine
      • La Jolla, California, United States, 92037
        • Recruiting
        • Orso Health
      • Los Angeles, California, United States, 90095
        • Recruiting
        • University of California, Los Angeles-UCLA
      • Torrance, California, United States, 90505
        • Withdrawn
        • Orso Health
    • Florida
      • St. Petersburg, Florida, United States, 33701
        • Recruiting
        • University of Southern Florida
    • Georgia
      • Atlanta, Georgia, United States, 30322
        • Recruiting
        • Children's Healthcare of Atlanta (CHOA)
    • Iowa
      • Iowa City, Iowa, United States, 52242
        • Recruiting
        • University of Iowa
    • Massachusetts
      • Boston, Massachusetts, United States, 02143
        • Recruiting
        • Boston Children's Cancer Center
    • Michigan
      • Ann Arbor, Michigan, United States, 48109
        • Recruiting
        • University of Michigan
    • Missouri
      • St Louis, Missouri, United States, 63130
        • Recruiting
        • Washington University
    • North Carolina
      • Durham, North Carolina, United States, 27710
        • Recruiting
        • Duke University Medical Center
    • Ohio
      • Cincinnati, Ohio, United States, 45229
        • Recruiting
        • Cincinnati Children's Hospital Medical Center
      • Cleveland, Ohio, United States, 44195
        • Recruiting
        • Cleveland Clinic
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19104
        • Recruiting
        • The Children's Hospital of Philadelphia
    • Tennessee
      • Memphis, Tennessee, United States, 38105
        • Recruiting
        • St. Jude Childrens; Research Hospital
    • Texas
      • Dallas, Texas, United States, 75390
        • Recruiting
        • UT Southwestern Medical Center
      • Fort Worth, Texas, United States, 76104
        • Recruiting
        • Cook Children's Medical Center
      • Houston, Texas, United States, 77030
        • Recruiting
        • Texas Children's Hospital/ Baylor College of Medicine
      • Woodland, Texas, United States, 77380
        • Recruiting
        • Sarah Cannon Research Institute
    • Utah
      • Salt Lake City, Utah, United States, 84112
        • Recruiting
        • University of Utah
    • Wisconsin
      • Milwaukee, Wisconsin, United States, 53226
        • Recruiting
        • Froedtert and Medical College of Wisconsin

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Key Inclusion Criteria:

  • Diagnosis of congenital or acquired primary autoimmune and idiopathic chronic neutropenic disorder ≥6 months prior to the screening visit that is not attributable to medications, active or recent infections or malignancy.

  • Congenital Neutropenia, including but not limited to these classifications:

    1. Isolated with a permanent (non-cyclic) presentation, for example, elastase, neutrophil expressed (ELANE), colony stimulating factor 3 receptor (CSF3R), C-X-C chemokine receptor 2 (CXCR2), Wiskott-Aldrich syndrome (WAS)
    2. Associated with extra-hematologic manifestations, for example, Barth syndrome, Cohen syndrome, glucose-6-phosphatase catalytic subunit 3 (G6PC3), Kostmann disease
    3. Associated with metabolic disorders, for example, glycogen storage disease 1b (GSD1b)
    4. Shwachman-Diamond syndrome

  • Acquired Primary Neutropenia

    1. Chronic idiopathic neutropenia
    2. Primary autoimmune neutropenia. Other chronic neutropenia (CN) disorders that may be eligible for enrollment can be clarified and approved upon discussion with study Medical Monitor.
  • Have an ANC <1000 cells/µL during screening (single ANC value from hematology) and confirmed trough mean ANC (mean value of multiple ANC measurements over 6 hours) at baseline visit, with no clinical evidence of systemic infection.
  • Prior history of recurrent and/or serious infections during the 12 months preceding the screening visit (that is, suffering sequelae of chronic neutropenia), as defined by having at least 2 infections in the last 12 months that meet the following criteria:
  • Infection requiring the use of antibiotics (intravenous [IV]/oral); OR
  • Infection requiring a visit to healthcare facility (including but not limited to emergency room visit, urgent care facility, primary care physician's office, or in-patient hospitalization);

AND for all potential participants:

  • Infections considered by the Investigator to be likely related to the potential participant's CN disorder.
  • Participants who are on G-CSF or other active background therapy must have been receiving these therapies during the previous 12 months while continuing to suffer from infections, be on a stable dose and dosing schedule for ≥4 weeks prior to screening visit and remain on this dose and dosing schedule throughout the study (unless ANC >10,000 cells/µL for ≥4 weeks).
  • Participants must be willing to keep their G-CSF or other background therapy doses/regimens stable (other than for safety reasons) for the duration of the study.

Key Exclusion Criteria:

  • A diagnosis of secondary neutropenia including those due to:

    1. Hypersplenism
    2. Infection
    3. Malignancy
    4. Autoimmune disease, for example, systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, graft-versus-host disease, thyroid disease
    5. Nutritional deficiency, for example, vitamin B12, folic acid, copper, caloric malnutrition
    6. Drug-induced cause, for example, chemotherapy, clozapine, antiretrovirals, antibiotics, monoclonal antibodies.

  • A diagnosis of any of the following:

    1. Aplastic anemia
    2. Warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) syndrome

    3. Certain CNs, including but not limited to these classifications are excluded:

      1. Isolated with a cyclic presentation, for example, elastase, neutrophil expressed (ELANE)
      2. Associated with immune dysregulation, for example, common variable immunodeficiency (CVID), autoimmune lymphoproliferative syndrome (ALPS), familial hemophagocytic lymphohistiocytosis, Chédiak-Higashi syndrome, GATA-binding protein 2 (GATA2) deficiency syndrome
      3. Associated with bone marrow failure, for example, Fanconi anemia, Diamond-Blackfan anemia
    4. Neutropenia associated with a Duffy-null phenotype (formerly known as benign ethnic neutropenia). However, a participant with an autosomal dominant pathogenic variant in a gene associated with CN on a Duffy-null background may be eligible for inclusion
  • A medical or personal condition that may potentially compromise the safety of the participant, may preclude the participant's successful completion of the clinical study, or could, in the opinion of the Investigator or the Medical Monitor, interfere with the objectives of the study.
  • Received more than 1 dose of mavorixafor in the past.
  • Received C-X-C chemokine receptor 4 (CXCR4) antagonist (other than mavorixafor) in the past 6 months.
  • Participants taking pegylated-G-CSF unless they have a diagnosis of congenital neutropenia confirmed at screening.
  • Participant is currently taking or has taken other investigational drug <30 days prior to the screening visit or 5 half-lives, whichever is longer.

Note: Other protocol-defined inclusion and exclusion criteria may apply.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Mavorixafor
Participants will receive mavorixafor orally once daily starting from Day 1 through Week 52.
Drug: Mavorixafor
Mavorixafor will be administered per schedule specified in the arm description.
Other Names:
  • X4P-001
Placebo Comparator: Placebo
Participants will receive placebo to match mavorixafor orally once daily starting from Day 1 through Week 52.
Drug: Placebo
Placebo will be administered per schedule specified in the arm description.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Co-primary Endpoint: Annualized Infection Rate Based on Infections Adjudicated by Blinded Infection Adjudication Committee (BIAC) During the Treatment Period
Time Frame: Up to 52 Weeks
Up to 52 Weeks
Co-primary Endpoint: Number of Participants Meeting the Definition of a Positive Absolute Neutrophil Count (ANC) Response
Time Frame: Up to 52 weeks
Positive ANC response: Increase of ANC >500 cells/microliter (µL) from baseline.
Up to 52 weeks

Secondary Outcome Measures

Outcome Measure
Time Frame
Infection Duration Based on Duration of Infections Adjudicated by a BIAC During the Treatment Period in Those Participants who Developed Infections
Time Frame: Up to 52 Weeks
Up to 52 Weeks
Antibiotic Use Due to Infection, Characterized by the Frequency of Antibiotic Use During the Treatment Period
Time Frame: Up to 52 Weeks
Up to 52 Weeks
Oral Ulcers, as Assessed by Presence or Absence of Ulcers During the Treatment Period
Time Frame: Up to 52 Weeks
Up to 52 Weeks
Change From Baseline in Patient Reported Outcomes Measurement Information System Short Form (PROMIS SF) Fatigue Questionnaire Total Score
Time Frame: Baseline, Week 52
Baseline, Week 52
Infection Severity Based on Common Terminology Criteria for Adverse Events (CTCAE) Adjudicated by a BIAC During the Treatment Period
Time Frame: Up to 52 Weeks
Up to 52 Weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

X4 Pharmaceuticals

Investigators

  • Study Director: Vice President Global Head of Clinical Development and Safety, X4 Pharmaceuticals

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 6, 2024

Primary Completion (Estimated)

September 1, 2027

Study Completion (Estimated)

November 1, 2027

Study Registration Dates

First Submitted

September 20, 2023

First Submitted That Met QC Criteria

September 20, 2023

First Posted (Actual)

September 28, 2023

Study Record Updates

Last Update Posted (Actual)

August 6, 2026

Last Update Submitted That Met QC Criteria

August 4, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • X4P-001-110
  • 2023-508482-32-00 (Ctis)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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