A Study of Mavorixafor in Participants With Congenital Neutropenia and Chronic Idiopathic Neutropenia Disorders

NCT04154488 | Completed Phase 1 DMC FDA Drug

• 1 other identifier: X4P-001-104
• Study Type: interventional
• Target: 32
• Locations: 1 country
• Sites: 7

Brief Summary

This is a 2-part study of mavorixafor in participants diagnosed with chronic neutropenia. The main goal of Part 1 (Phase 1b) is to help researchers learn more about how the investigational medicine, mavorixafor, impacts people living with chronic neutropenia (including congenital, idiopathic, and cyclic). In Part 2 (Phase 2), the safety and tolerability of chronic dosing of mavorixafor will be evaluated in a larger participant population and the impact of 6-month chronic dosing of mavorixafor on participant neutropenia.

Conditions

Neutropenia

Keywords

Chronic congenital neutropenia; Chronic idiopathic neutropenia; SCN; CIN; CXCR4; Mavorixafor; Neutropenia glycogen storage disease type 1b; GSD1b; G6PC3; SLC37A4; GATA2

Outcome Measures

Primary Outcomes (4)

• Number of Participants With Treatment-Emergent Adverse Events (TEAEs) After a Single Dose of Mavorixafor

  Baseline through Day 1 and 7 days follow-up

• Number of Participants With Treatment-Emergent Adverse Events (TEAEs) After Multiple Doses of Mavorixafor

  Baseline through Month 6 and 30 days follow-up

• Change From Baseline in Absolute Neutrophil Count (ANC) to 8 hours Post-dose On Day 1

  Baseline, 8 hours Post-dose On Day 1

• Change From Baseline in ANC to Month 6

  Baseline, Month 6

Secondary Outcomes (9)

• Serum Concentration of Mavorixafor in Relation to ANC and Area Under the Curve (AUC) for ANC (AUCANC)

  0 (pre-dose), 60 minutes and 2, 3, 4, 6, and 8 hours post-dose on Day 1

• Serum Concentrations of Mavorixafor

  0 (pre-dose) up to Month 6

• Change from Baseline in Absolute Lymphocyte Count (ALC)

  Baseline, Month 6

• Change from Baseline in Total White Blood Cells (WBC)

  Baseline, Month 6

• Change from Baseline in Absolute Monocyte (AMC)

  Baseline, Month 6

Study Arms (1)

Mavorixafor

EXPERIMENTAL

Part 1: Adult participants and adolescent participants who weigh more than 50 kilograms (kg) will receive mavorixafor 400 milligrams (mg) (4 capsules of 100 mg each), orally once on Day 1. Adolescents weighing less than or equal to 50 kg will receive mavorixafor 200 mg (2 capsules of 100 mg each), orally once on Day 1. Part 2: Eligible participants from Part 1 will receive once daily dosing of mavorixafor for 6 months.

Drug: Mavorixafor

Interventions

Mavorixafor DRUG

Mavorixafor capsules will be administered per dose and schedule specified in the arm.

Also known as: X4P-001

Mavorixafor

Eligibility Criteria

• Age: 12 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

• For all participants (Parts 1 and 2):
• Sign the informed consent form (ICF) and be willing and able to comply with the protocol.
• Weigh ≥15 kg
• Agree to use a highly effective form of contraception if sexually active.
• Participants may be eligible for the study whether they are on or off granulocyte-colony stimulating factor (G-CSF) treatment.
• Note: Participants who are on G-CSF must be on a stable dose for ≥14 days prior to the Baseline visit and should not have an ANC ≥10,000 cells/μL.
• Note: Participants who are not on G-CSF must be off for ≥14 days prior to the Baseline visit and have an ANC ≤1000 cells/µL at the Screening visit.
• Note: Participants with Shwachman-Diamond syndrome, Cohensyndrome, and warts, hypogammaglobulinemia, infections and myelokathexis syndrome are eligible. Other types of chronic neutropenic disorders may also be eligible for enrollment upon discussion and approval with Sponsor and Study Medical Monitor.
• Have been diagnosed with chronic neutropenia for ≥6 months prior to the Screening visit that is not attributable to medications, active or recent (≤3 months) infections, or malignant cause.
• Part 2 only:
• Participants enrolled in the study before implementation of Protocol Version 8.0 must have completed Part 1 and exhibited a positive response to treatment.
• Participant has a history of symptomatic chronic neutropenia confirmed by the Investigator.

You may not qualify if:

• Known systemic hypersensitivity to the mavorixafor drug substance or its inactive ingredients.
• Is pregnant, breastfeeding, or plans to become pregnant over the next 8 months.
• Known history of a positive serology or viral load for human immunodeficiency virus (HIV) or a known history of acquired immune deficiency syndrome.
• Known active SARS-CoV-2 virus (COVID-19) infection or a positive test within the local accepted clinical and governmental guidelines for a communicable window.
• At the Screening Visit, has laboratory test results meeting one or more of the following criteria:
• Positive hepatitis C virus (HCV) antibodies with confirmation by HCV-ribonucleic acid polymerase chain reaction reflex testing.
• Positive hepatitis B surface antigen (hBsAg) or hepatitis B core antibody (hBcAb).
• Note: If a participant tests negative for hBsAg but positive for hBcAb, the participant would be considered eligible if the participant tests positive for antibody to hBsAg reflex testing.
• At the Screening visit, has laboratory test results meeting one or more of the following criteria:
• Hemoglobin \<9.0 grams/deciliter (g/dL)
• Platelets \<30,000/μL
• Estimated glomerular filtration rate (eGFR) ≤60 mL/minute/1.73 meter (m)\^2, as estimated by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation
• Serum aspartate transaminase \>2.5 x upper limit of normal (ULN)
• Serum alanine transaminase \>2.5 x ULN
• Total bilirubin \>1.5 x ULN (unless due to Gilbert's syndrome, in which case total bilirubin greater than or equal to (≥) 3.0 x ULN and direct bilirubin \>1.5 x ULN)

Sponsors & Collaborators

• X4 Pharmaceuticals: lead

Study Sites (7)

USF Health Department of Pediatrics

St. Petersburg, Florida, 33701, United States

Location

University of Iowa Hospital and Clinics

Iowa City, Iowa, 52242, United States

Location

University of Michigan

Ann Arbor, Michigan, 48109, United States

Location

Washington University School of Medicine

St Louis, Missouri, 63110, United States

Location

Children's Hospital of Philadelphia

Philadelphia, Pennsylvania, 19104, United States

Location

University of Texas, Southwestern

Dallas, Texas, 75235, United States

Location

University of Washington

Seattle, Washington, 98195, United States

Location

MeSH Terms

Conditions

Neutropenia; Glycogen Storage Disease Id

Interventions

mavorixafor

Condition Hierarchy (Ancestors)

Agranulocytosis; Leukopenia; Cytopenia; Hematologic Diseases; Hemic and Lymphatic Diseases; Leukocyte Disorders

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: November 4, 2019
• First Posted: November 6, 2019
• Study Start: October 16, 2021
• Primary Completion: August 27, 2024
• Study Completion: August 27, 2024
• Last Updated: August 6, 2025

Record last verified: 2025-08

Locations

US (7)