NCT03995108

A Phase 3, Randomized, Double-Blind, Placebo-Controlled, Multicenter Study of Mavorixafor in Patients With WHIM Syndrome With Open-Label Extension

Active, enrolled Phase 3 Last updated 28 July 2025

What this trial tests

Phase 3 trial testing Mavorixafor in WHIM Syndrome in 31 participants. Participants enrolled and being followed up; not accepting new ones.

Timeline

24 October 2019

Primary endpoint
1 December 2025

1 December 2025

Quick facts

Lead sponsor	X4 Pharmaceuticals
Phase	Phase 3
Status	Active, enrolled
Study type	INTERVENTIONAL
Allocation	randomized
Design	parallel
Masking	double
Primary purpose	treatment
Enrollment	31
Start date	24 October 2019
Primary completion	1 December 2025
Estimated completion	1 December 2025
Sites	23 locations across United States, Australia, Austria, Denmark, France, Hungary, Israel, Italy

Drugs / interventions tested

• Mavorixafor (MAVORIXAFOR) — full drug profile →
• Placebo

Conditions studied

• WHIM Syndrome — all drugs for WHIM Syndrome →

Sponsor

X4 Pharmaceuticals — full company profile →

Who can join

12 and older, any sex, with WHIM Syndrome. Patients with the condition only — healthy volunteers not accepted.

What's being measured

Primary outcomes are the specific endpoints the trial is designed to prove or disprove.

• Randomized Placebo-Controlled Period: Time (in Hours) Above Threshold-Absolute Neutrophil Count (TAT-ANC in hours) of ≥ 500 Cells/Microliter (µL) over a 24-hour period
  Time frame: Time 0 (pre-dose, up to 15 minutes prior), 30, 60, and 90 min (each ± 5 min) and 2, 3, 4, 8, 12, 16, and 24 hours (each ± 15 min) post-dose at Baseline, Weeks 13, 26, 39, and 52
• Open-Label Period: Percentage of Participants With Adverse Events (AEs)
  Time frame: From Day 1 (end of randomized period) up to end of study (30 days post-treatment in open-label period [Week 56 of open-label period])

Sponsor's own description

This study has a double-blind, Randomized Placebo-Controlled Period and an Open-Label Period. The primary objective of the Randomized Placebo-Controlled Period is to demonstrate the efficacy of mavorixafor in participants with WHIM syndrome as assessed by increasing levels of circulating neutrophils compared with placebo, and relative to a clinically meaningful threshold. The primary objective of the Open-Label Period is to evaluate the safety and tolerability of mavorixafor in participants with WHIM syndrome. Participants are allowed to continue treatment in the Open-Label Period, if regionally applicable, until mavorixafor becomes commercially available, or until the study is terminated by the Sponsor.

Publications & conference data

8 peer-reviewed publications reference this trial (live from Europe PMC):

1. The chemokines CXCL8 and CXCL12: molecular and functional properties, role in disease and efforts towards pharmacological intervention.
   Cambier S, Gouwy M, Proost P. · · 2023 · cited 387× · PMID 36725964 · DOI 10.1038/s41423-023-00974-6
2. Clinical cancer immunotherapy: Current progress and prospects.
   Liu C, Yang M, Zhang D, Chen M, et al · · 2022 · cited 147× · PMID 36304470 · DOI 10.3389/fimmu.2022.961805
3. Neutrophil diversity and function in health and disease.
   Zhang F, Xia Y, Su J, Quan F, et al · · 2024 · cited 109× · PMID 39638788 · DOI 10.1038/s41392-024-02049-y
4. The CXCL12 Crossroads in Cancer Stem Cells and Their Niche.
   López-Gil JC, Martin-Hijano L, Hermann PC, Sainz B. · · 2021 · cited 46× · PMID 33530455 · DOI 10.3390/cancers13030469
5. A phase 3 randomized trial of mavorixafor, a CXCR4 antagonist, for WHIM syndrome.
   Badolato R, Alsina L, Azar A, Bertrand Y, et al · · 2024 · cited 42× · PMID 38643510 · DOI 10.1182/blood.2023022658
6. New genetic and epigenetic insights into the chemokine system: the latest discoveries aiding progression toward precision medicine.
   Xu H, Lin S, Zhou Z, Li D, et al · · 2023 · cited 37× · PMID 37198402 · DOI 10.1038/s41423-023-01032-x
7. Biased action of the CXCR4-targeting drug plerixafor is essential for its superior hematopoietic stem cell mobilization.
   Jørgensen AS, Daugvilaite V, De Filippo K, Berg C, et al · · 2021 · cited 34× · PMID 33980979 · DOI 10.1038/s42003-021-02070-9
8. Targeting the CXCR4/CXCL12 Axis in Cancer Therapy: Analysis of Recent Advances in the Development of Potential Anticancer Agents.
   Smaldone G, Di Matteo F, Castelluccio R, Napolitano V, et al · · 2025 · cited 13× · PMID 40142155 · DOI 10.3390/molecules30061380