A Dose Determination and Safety Study of X4P-001 (Mavorixafor) in Participants With Warts, Hypogammaglobulinemia, Infections, and Myelokathexis (WHIM) Syndrome

Mean Value of the Area Under the Plasma Concentration-time Curve for Absolute Neutrophil Count (AUCANC)

AUCANC was collected over a 24-hour period above clinically meaningful thresholds for the mavorixafor-treated participants over 6 months. The absolute neutrophil count (ANC) clinically meaningful threshold was defined as ANC ≥ 600/microliter (μL).

Time frame: 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

All Visits: Average Per-Participant Value of the AUCANC

AUCANC was collected over a 24-hour period above clinically meaningful thresholds for the mavorixafor-treated participants over 6 months. The ANC clinically meaningful threshold was defined as ANC ≥ 600/μL. Data for this outcome measure are reported as an "All Visits" summary based on the mean of AUCs that is, the per-participant average of the AUCANC across the 3 visits where participant was treated with at least 300/400 mg dose. Time frame reported is based on data collection time points.

Time frame: Time 0 (-15 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

Mean Value of the Area Under the Plasma Concentration-time Curve for Absolute Lymphocyte Count (AUCALC)

AUCALC was collected over a 24-hour period above clinically meaningful thresholds for the mavorixafor-treated participants over 6 months. The absolute lymphocyte count (ALC) clinically meaningful threshold was defined as ALC ≥ 1000/μL.

Time frame: Time 0 (-15 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

All Visits: Average Per-Participant Value of the AUCALC

AUCALC was collected over a 24-hour period above clinically meaningful thresholds for the mavorixafor-treated participants over 6 months. The ALC clinically meaningful threshold was defined as ALC ≥ 1000/μL. Data for this outcome measure are reported as an "All Visits" summary based on the mean of AUCs that is, the per-participant average of the AUCALC across the 3 visits where participant was treated with at least 300/400 mg dose. Time frame reported is based on data collection time points.

Time frame: Time 0 (-15 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

Number of Participants With Treatment-Emergent Adverse Events (TEAEs)

An adverse event (AE) was defined as any untoward medical occurrence that developed or worsened in severity during the conduct of a clinical study and did not necessarily have a causal relationship to the study drug. SAEs included death, a life-threatening adverse event, inpatient hospitalization or prolongation of existing hospitalization, persistent or significant disability or incapacity, a congenital anomaly or birth defect, or an important medical event that jeopardized the participant and required medical intervention to prevent 1 of the outcomes listed in this definition. A TEAE was defined as any AE that began or worsened in severity or frequency on or after the start of study drug through 10 days after the last dose of the study drug. A summary of serious and non-serious AEs regardless of causality is located in 'Reported Adverse Events module'.

Time frame: From first dose of study drug through 10 days after the last dose of the study drug (Maximum exposure: 1712 days)