A Phase 3 interventional study of Mavorixafor and Placebo in WHIM Syndrome, sponsored by X4 Pharmaceuticals. Completed at 23 sites in 13 countries. Open to participants aged 12 Years and older. Per ClinicalTrials.gov, last updated 2026-07-06.
Sponsored by X4 Pharmaceuticals · Phase 3, Interventional, and Treatment
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.
X4 Pharmaceuticals is the lead sponsor of 13 studies on the registry; 2 are open to participants now.
Of its 10 completed or terminated interventional studies of FDA-regulated products, 3 (30%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Inclusion Criteria for the Randomized Placebo-Controlled Period :
Inclusion Criteria for the Open-Label Period:
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Drug: Mavorixafor
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.
Drug: Mavorixafor · Drug: Placebo
Mavorixafor provided as 100 mg capsules.
Also known as: AMD11070, X4P-001
Placebo matching to mavorixafor capsules
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])
Randomized Placebo-Controlled Period: Time (in Hours) Above Threshold-Absolute Lymphocyte Count (TAT-ALC) of ≥ 1000 Cells/µL over a 24-hour period
Time frame: Time 0 (pre-dose, up to 15 minutes prior), 30, 60, and 90 minutes (each ± 5 minutes) and 2, 3, 4, 8, 12, 16, and 24 hours (each ± 15 minutes) post-dose at Baseline, Weeks 13, 26, 39, and 52
Randomized Placebo-Controlled Period: Composite Clinical Efficacy for Mavorixafor based on total infection score and total wart change score
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: Change From Baseline in Total Warts Score at Week 52
Time frame: Baseline, Week 52
Randomized Placebo-Controlled Period: Total Infection Score for Mavorixafor
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: Time to Early Release
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: TAT-ALC of ≥ 1000 Cells/µL in Participants With Lymphopenia
Time frame: Baseline
Randomized Placebo-Controlled Period: Total Infection Score for Participants With Non-Immunoglobulin (non-Ig) Use (Percentage of Participants With Infections)
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: Change in Total Wart Score at Baseline, Based on Clinical Global Impression of Change (CGI-C)
Time frame: Baseline
Randomized Placebo-Controlled Period: Composite Clinical Efficacy (Total Infection Score and Total Wart Change Score) for Participants With Non-Ig Use
Composite clinical efficacy will be calculated using the total infection score and total wart change score for participants with warts at baseline or non-Ig use. It will be analyzed by a blinded, independent AC.
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: Change in Total Wart Score at Baseline (CGI-C), Based on Local Dermatologist Review
Time frame: Baseline
Randomized Placebo-Controlled Period: Participant Global Impression of Change (PGI-C)
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: Participant Global Impression of Severity (PGI-S)
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: Vaccine Titer Levels at Week 52 in Participants Vaccinated at Week 13, With Tetanus, Diphtheria, and Pertussis (Tdap) Including Pertussis Toxin, and Tetanus
Time frame: Week 52
Randomized Placebo-Controlled Period: Vaccine Titer Levels at Week 52 for Human Papillomavirus (HPV) 16 and HPV 18 in Participants Receiving Vaccinations With HPV 9-Valent Vaccine, Recombinant (Gardasil®9)
Time frame: Week 52
Randomized Placebo-Controlled Period: Change From Baseline in Clinical Global Impression of Severity (CGI-S), Based on Local Dermatologist Review
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: Number of Participants with Infections
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: Infection-Free Time
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: Number of Days Lost From Work/School
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: Quality of Life as Measured by 36-Item Short Form Survey Score
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: Quality of Life as Measured by EuroQoL-5 Dimension-5 Level (EQ-5D-5L) Score
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: Quality of Life as Measured by Life Quality Index (LQI) Score
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: Quality of Life as Measured by Dermatology LQI Score
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: Quality of Life as Measured by Pediatric Quality of Life Inventory (PedsQL) Score
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: Change From Baseline in Anogenital (AG) Warts Based on Dermatologist CGI-C Assessment
Time frame: Baseline to Week 52
Randomized Placebo-Controlled Period: Change From Baseline in Anogenital (AG) Warts Based on AG Wart Severity Assessment
Time frame: Baseline to Week 52
Randomized Placebo-Controlled Period: Number of Events Requiring Rescue Treatment Due to Infection
Time frame: Baseline to Week 52
Randomized Placebo-Controlled Period: Number of Participants With Incidence and Duration of Hospitalizations Due to Infection
Time frame: Baseline to Week 52
Randomized Placebo-Controlled Period: Number of Participants With Incidence of Newly Developed Warts
Time frame: Baseline to Week 52
Randomized Placebo-Controlled Period: Area Under the Curve for ANC (AUCANC) Using Trapezoidal Method
Time frame: Time 0 (pre-dose, up to 15 minutes prior), 30, 60, and 90 minutes (each ± 5 minutes) and 2, 3, 4, 8, 12, 16, and 24 hours (each ± 15 minutes) post-dose at Baseline, Weeks 13, 26, 39, and 52
Randomized Placebo-Controlled Period: Percentage of Neutrophil Responders
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: Mavorixafor Treatment Group: AUCANC
Time frame: Time 0 (pre-dose, up to 15 minutes prior), 30, 60, and 90 minutes (each ± 5 minutes) and 2, 3, 4, 8, 12, 16, and 24 hours (each ± 15 minutes) post-dose at Baseline, Weeks 13, 26, 39, and 52
Randomized Placebo-Controlled Period: Area Under the Curve for ALC (AUCALC)
Time frame: Time 0 (pre-dose, up to 15 minutes prior), 30, 60, and 90 minutes (each ± 5 minutes) and 2, 3, 4, 8, 12, 16, and 24 hours (each ± 15 minutes) post-dose at Baseline, Weeks 13, 26, 39, and 52
Randomized Placebo-Controlled Period: Percentage of Lymphocyte Responders
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: Change From Baseline in Total ALC, Absolute Monocyte Count (AMC), ANC, and White Blood Cell (WBC) at Week 52
Time frame: Baseline, Week 52
Absolute and Fold Change From Baseline in Absolute T, B and Natural Killer Lymphocyte at Week 52
Time frame: Baseline, Week 52
Randomized Placebo-Controlled Period: Number of Participants With AEs
Time frame: Baseline up to Week 52
Randomized Placebo-Controlled Period: Pharmacokinetics (PK), Maximum Observed Plasma Concentration (Cmax) of Mavorixafor
Time frame: Time 0 (pre-dose, up to 15 minutes prior), 30, 60, and 90 minutes (each ± 5 minutes) and 2, 3, 4, 8, 12, 16, and 24 hours (each ± 15 minutes) post-dose at Weeks 13, 26, 39, and 52; and 4 hours post-dose at Baseline
Randomized Placebo-Controlled Period: PK, Time to Reach Cmax (Tmax) of Mavorixafor
Time frame: Time 0 (pre-dose, up to 15 minutes prior), 30, 60, and 90 min (each ± 5 minutes) and 2, 3, 4, 8, 12, 16, and 24 hours (each ± 15 minutes) post-dose at Weeks 13, 26, 39, and 52; and 4 hours post-dose at Baseline
Randomized Placebo-Controlled Period: PK, Half-Life of (T1/2) of Mavorixafor
Time frame: Time 0 (pre-dose, up to 15 minutes prior), 30, 60, and 90 minutes (each ± 5 minutes) and 2, 3, 4, 8, 12, 16, and 24 hours (each ± 15 minutes) post-dose at Weeks 13, 26, 39, and 52; and 4 hours post-dose at Baseline
Randomized Placebo-Controlled Period: PK, Area Under the Curve (AUC) of Mavorixafor
Time frame: Time 0 (pre-dose, up to 15 minutes prior), 30, 60, and 90 minutes (each ± 5 minutes) and 2, 3, 4, 8, 12, 16, and 24 hours (each ± 15 minutes) post-dose at Weeks 13, 26, 39, and 52; and 4 hours post-dose at Baseline
Open-Label Period: Percentage of Neutrophil Responders
Time frame: Baseline up to Week 52 of open-label period
Open-Label Period: Percentage of Lymphocyte Responders
Time frame: Baseline up to Week 52 of open-label period
Open-Label Period: Absolute and Fold Change From Baseline in Total ALC, AMC, ANC, and WBC at Week 52
Time frame: Baseline up to Week 52 of open-label period
Open-Label Period: Vaccine Titer Levels During the First Year of Open-Label Period, in Participants Vaccinated With Tdap During the Study Including Pertusis Toxin and Tetanus
Time frame: Year 1 of open-label period
Open-Label Period: Vaccine Titer Levels During the First Year of the Open-Label Period for HPV 16 and HPV 18 in Participants Receiving Vaccinations With HPV 9-Valent Vaccine, Recombinant (Gardasil®9) During the Study
Time frame: Year 1 of open-label period
Open-Label Period: Change From Baseline in Cutaneous Warts at Week 52, Based on Central Review of CGI-C
Time frame: Baseline, Week 52 of open-label period
Open-Label Period: Change From Baseline in Cutaneous Warts, Based on Central Review of CGI-S
Time frame: Baseline, Week 52 of open-label period
Open-Label Period: Change From Baseline in Cutaneous Warts, Based on Local Dermatologist CGI-C
Time frame: Baseline, Week 52 of open-label period
Open-Label Period: Change From Baseline in Cutaneous Warts, Based on Local Dermatologist CGI-S
Time frame: Baseline, Week 52 of open-label period
Open-Label Period: Change Over Time in PGI-C
Time frame: Baseline up to Week 52 of open-label period
Open-Label Period: Change Over Time in PGI-S
Time frame: Baseline up to Week 52 of open-label period
Open-Label Period: Total Infection Score (Percentage of Participants With Infections)
Time frame: Baseline up to Week 52 of open-label period
Plan to share: No
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Studies of the drug tested here: Mavorixafor
WHIM syndrome
X4 Pharmaceuticals