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

X4 Pharmaceuticals

Status and phase: Active, not recruiting; Phase 3

Conditions: WHIM Syndrome

Treatments: Drug: Placebo; Drug: Mavorixafor

Study type: Interventional

Funder types: Industry

Identifiers

NCT03995108

2019-001153-10 (EudraCT Number)

X4P-001-103

4WHIM (Other Identifier)

Details and patient eligibility

About

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.

Enrollment: 31 patients

Sex: All

Ages: 12+ years old

Volunteers: No Healthy Volunteers

Inclusion and exclusion criteria

Inclusion Criteria for the Randomized Placebo-Controlled Period :

• 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/µL 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.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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31 participants in 2 patient groups, including a placebo group

Mavorixafor

Experimental group

Description:

Participants (adults and adolescents \[12 to 17 years of age weighing \>50 kilograms \[kg\]) will receive mavorixafor 400 milligrams (mg) once daily (QD) orally for 52 weeks in the Randomized Placebo-Controlled Period. Adolescents weighing ≤50 kg will receive mavorixafor 200 mg QD. Participants who complete the Randomized Placebo-Controlled Period or are granted Early Release due to recurrent or significant infections, as adjudicated by a blinded, independent adjudication committee (AC), will be offered the opportunity to enroll in the Open-Label Period and receive treatment with mavorixafor 400 mg once daily orally until commercial availability or study termination by the Sponsor.

Treatment:

Drug: Mavorixafor

Placebo

Placebo Comparator group

Description:

Participants will receive placebo matching to mavorixafor QD orally for 52 weeks in the Randomized Placebo-Controlled Period. Participants who complete the Randomized Placebo-Controlled Period or are granted Early Release due to recurrent or significant infections, as adjudicated by a blinded, independent AC, will be offered the opportunity to enroll in the Open-Label Period and receive treatment with mavorixafor 400 mg once daily orally until commercial availability or study termination by the Sponsor.

Treatment:

Drug: Mavorixafor

Drug: Placebo