In short
Clinical trials are investigating Mavorixafor in people with WHIM syndrome and chronic neutropenic disorders. These studies look at whether it can improve blood cell counts, reduce infections, and stay safe over time. The trials include adults and other eligible participants in Phase 3 studies.
Key points
- Mavorixafor is being studied in Phase 3 clinical trials for WHIM syndrome and for congenital or acquired chronic neutropenic disorders. One completed study looked at whether it could improve neutrophil levels and keep them above a target threshold in people with WHIM syndrome. Another authorised study is testing whether it can lower infection rates and improve neutrophil response in people with chronic neutropenia, including those with recurrent or serious infections. The trials also measure safety and tolerability, especially over longer treatment periods. Together, these studies focus on whether Mavorixafor can help people whose low neutrophil counts put them at risk for infections.
Clinical trials overview
These studies are testing Mavorixafor in people with blood disorders that cause low neutrophil counts and repeated infections. The trial data show two Phase 3 interventional studies, one completed and one authorised.
In clinical research, interventional means the study gives a treatment and then measures what happens. Both studies compare Mavorixafor with placebo in at least part of the trial, which helps researchers see whether the study drug performs better than no active drug.
WHIM syndrome study
NCT03995108 studied people with WHIM Syndrome, a rare condition marked by warts, low antibody levels, infections, and myelokathexis. The study was completed and enrolled 14 participants.
This trial had a randomized placebo-controlled period and an open-label period. Randomized means participants are assigned by chance, and placebo-controlled means some people received a look-alike treatment without active drug for comparison. Open-label means both the researchers and participants know the treatment being given.
The main goal was to show that Mavorixafor could raise circulating neutrophils compared with placebo and reach a clinically meaningful threshold. A key outcome was the time above threshold-absolute neutrophil count, or TAT-ANC, meaning how long the neutrophil count stayed at or above 500 cells/μL over 24 hours.
The open-label part focused on long-term safety and tolerability. Safety was checked through adverse events, laboratory tests, vital signs, ECGs, physical exams, and eye exams.
Chronic neutropenia study
NCT06056297 is studying Mavorixafor in participants with congenital and acquired primary autoimmune and idiopathic chronic neutropenic disorders who have recurrent and/or serious infections. The trial is authorised, is Phase 3, and plans to enroll 214 participants.
This study also includes a placebo capsule comparison. The trial is looking at people with chronic neutropenia who are not receiving chronic G-CSF treatment, as well as the overall population regardless of background therapy. G-CSF is a treatment used to help the body make more neutrophils.
The main outcome is the annualized infection rate based on infections reviewed by a BIAC, which is a committee that checks and confirms infection events in the study. The study also measures ANC responders, meaning participants who meet a target neutrophil response in at least 3 of 6 planned visits during the 52-week treatment period.
For some participants, a positive ANC response means an ANC of at least 1500 cells/μL. For participants whose starting ANC is below 500 cells/μL, a response can also mean at least a 2-fold increase from baseline, which means the count doubles from the starting level.
What the trials measure
Across these studies, the main focus is on neutrophil counts, infections, and safety. Neutrophils are a type of white blood cell that help fight infection, so low counts can leave people at higher risk.
- Neutrophil improvement: The WHIM syndrome study measured how long ANC stayed above a set threshold, while the neutropenia study measured how many participants reached a defined ANC response.
- Infection control: The chronic neutropenia study tracked the annualized infection rate, which is the number of infections over a year adjusted for study time.
- Safety and tolerability: The WHIM syndrome study followed adverse events, lab tests, vital signs, ECGs, and physical and eye exams to see how well people handled treatment.
Who may participate
The WHIM syndrome study included participants with WHIM syndrome. The chronic neutropenia study includes participants with congenital or acquired primary autoimmune and idiopathic chronic neutropenic disorders who are having recurrent and/or serious infections.
These studies are not for the general public; they are for people who meet the trial rules, sometimes called eligibility criteria. The available data also show that one study focused on people not receiving chronic G-CSF treatment.
Study design and phases
Both trials are Phase 3 studies, which usually means the treatment has already been studied in earlier research and is now being tested in larger groups. Phase 3 trials are important because they help show whether a treatment works in real patient groups and how safe it is over time.
The WHIM syndrome study used a randomized placebo-controlled period followed by an open-label period. The chronic neutropenia study is also interventional and uses placebo capsules for comparison. Together, these designs help researchers compare outcomes fairly and collect longer-term data on treatment response.