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Trial details imported from

For full trial details, please see the original record at

Registration number
Ethics application status
Date submitted
Date registered
Date last updated

Titles & IDs
Public title
A Dose Determination and Safety Study of X4P-001 (Mavorixafor) in Participants With Warts, Hypogammaglobulinemia, Infections, and Myelokathexis (WHIM) Syndrome
Scientific title
A Phase 2, Open-Label, Multi-Center Trial of Mavorixafor in Patients With WHIM Syndrome
Secondary ID [1] 0 0
Secondary ID [2] 0 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
WHIM Syndrome 0 0
Condition category
Condition code
Other 0 0 0 0
Research that is not of generic health relevance and not applicable to specific health categories listed above

Study type
Description of intervention(s) / exposure
Treatment: Drugs - X4P-001

Experimental: X4P-001 - Initial Treatment Phase: Participants will initiate treatment with mavorixafor at 50 milligrams (mg) once daily (QD) orally or a higher dose, with potential escalation based on area under the curve for absolute neutrophil count and absolute leukocyte count (AUCANC/ALC) values to a maximum total daily dose of 400 mg. Participants are expected to receive treatment for 24 weeks in the initial Treatment Period or until development of a treatment-limiting toxicity (TLT).
Extension Phase: All participants will receive mavorixafor; the dose will not exceed 400 mg. In the Extension Phase, treatment may continue until mavorixafor becomes available via an alternative mechanism (for example, drug is commercially available, an expanded access program, etc.) or until the study is terminated by the sponsor.

Treatment: Drugs: X4P-001
Mavorixafor will be provided as either 25 mg or 100 mg capsules.

Intervention code [1] 0 0
Treatment: Drugs
Comparator / control treatment
Control group

Primary outcome [1] 0 0
Timepoint [1] 0 0
Time 0 (-15 minutes [min] pre-dose), 30, 60, and 90 min (each ± 5 min) and 2, 3, 4, 8, 12, 16, and 24 hours (each ±15 min) at Weeks 5, 13, and 21

Key inclusion criteria
Participants with a clinical diagnosis of WHIM syndrome must meet all of the following
criteria to be eligible for study participation:

1. Be at least 18 years of age.

2. Has signed the current approved informed consent form.

3. Has a genotype-confirmed mutation of chemokine receptor type 4 (CXCR4) consistent with
WHIM syndrome.

4. Agree to use effective contraception.

5. Be willing and able to comply with this protocol.

6. Has confirmed ANC less than or equal to (=) 400/µL or ALC =650/µL or both.
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Participants with any of the following will be excluded from participation in the study:

1. Has known systemic hypersensitivity to the mavorixafor drug substance or its inactive

2. Is pregnant or nursing.

3. Has a known history of a positive serology or viral load for human immunodeficiency
virus (HIV) or a known history of acquired immunodeficiency syndrome (AIDS).

4. Has, at Screening, laboratory tests meeting one or more of the following criteria:

- A positive antibody test for hepatitis C virus (HCV), unless documented to have
no detectable viral load on 2 independent samples.

- A positive test for hepatitis B surface antigen (HBsAg).

5. Has any medical or personal condition that, 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.

Study design
Purpose of the study
Allocation to intervention
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Single group
Other design features
Phase 2
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Active, not recruiting
Data analysis
Reason for early stopping/withdrawal
Other reasons
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 0 0
St. Vincent's Hospital - Fitzroy
Recruitment postcode(s) [1] 0 0
3065 - Fitzroy
Recruitment outside Australia
Country [1] 0 0
United States of America
State/province [1] 0 0

Funding & Sponsors
Primary sponsor type
Commercial sector/Industry
X4 Pharmaceuticals

Ethics approval
Ethics application status

Brief summary
This is a Phase 2 study with an initial 24-week Treatment Period and an Extension Phase. The
primary objectives of this Phase 2 study are to determine the safety, tolerability, and dose
selection of mavorixafor in participants with WHIM syndrome. Participants are allowed to
continue treatment in an Extension Phase, if regionally applicable, until it becomes
commercially available or until the study is terminated by the Sponsor.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 0 0
Chief Medical Officer
Address 0 0
X4 Pharmaceuticals
Country 0 0
Phone 0 0
Fax 0 0
Email 0 0
Contact person for public queries
Name 0 0
Address 0 0
Country 0 0
Phone 0 0
Fax 0 0
Email 0 0
Contact person for scientific queries

Summary results
Other publications