Efficacy and Safety Study of Mavorixafor in Participants With Warts Hypogammaglobulinemia Infections and Myelokathexis (WHIM) Syndrome

  • End date
    Oct 7, 2022
  • participants needed
  • sponsor
    X4 Pharmaceuticals
Updated on 7 June 2021
Sarah Blanchette, PhD
Primary Contact
Children's Health Queensland Hospital (6.3 mi away) Contact
+23 other location


This study has a double-blind, placebo-controlled Randomized Period and an Open-Label extension Period. The primary objective of the Randomized 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 extension Period, if regionally applicable, until mavorixafor becomes commercially available, or until the study is terminated by the Sponsor.

Condition WHIM Syndrome
Treatment Placebo, Mavorixafor
Clinical Study IdentifierNCT03995108
SponsorX4 Pharmaceuticals
Last Modified on7 June 2021


Yes No Not Sure

Inclusion Criteria

Have signed the current approved informed consent form. Participants under 18 years of age (in the Netherlands and other applicable regions, participants under 16 years of age) will sign an approved informed assent form and must also have a signed parental/legal guardian consent
Have a genotype-confirmed mutation of chemokine (C-X-C motif) receptor 4 (CXCR4) consistent with WHIM phenotype
Agree to use a highly effective form of contraception
Be willing and able to comply with the protocol
Have confirmed ANC 400 cells/L during screening, obtained while participant has no clinical evidence of infection
Inclusion Criteria for the Open-Label Period
Completed the Randomized Period; or
Granted Early Release from the Randomized Period

Exclusion Criteria

Has known systemic hypersensitivity to the mavorixafor drug substance, its inactive ingredients, or the placebo
Is pregnant or breastfeeding
Has any medical or personal condition, which in the opinion of the Investigator may potentially compromise the safety or compliance of the participant or may preclude the participant's successful completion of the clinical study
Exclusion Criteria for the Open-Label Period
Participants who experience any treatment-limiting toxicity (TLT) will be excluded from participating in the Open-Label Period
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