Acquired Primary Autoimmune and Idiopathic Chronic Neutropenia DisordersPhase 2NCT07902830
A Study to Investigate the Safety and Tolerability of Granulocyte-colony Stimulating Factor (G-CSF) Dosage Reduction in Mavorixafor-treated Participants With Acquired Primary Autoimmune and Idiopathic Chronic Neutropenia Disorders
A Phase 2 study testing Mavorixafor in people with Acquired Primary Autoimmune and Idiopathic Chronic Neutropenia Disorders and Chronic Neutropenia, run by X4 Pharmaceuticals.
Trial summary
The purpose of this study is to evaluate the safety and tolerability of G-CSF dosage reduction with mavorixafor in participants with autoimmune neutropenia (AIN) and chronic idiopathic neutropenia (CIN) disorders as assessed by the ability to safely reduce G-CSF dosage with mavorixafor treatment while maintaining… Read more about this study
- Who is it for?
- Ages 12 years and older
- Conditions the study is for
- Acquired Primary Autoimmune and Idiopathic Chronic Neutropenia Disorders, Chronic Neutropenia, Autoimmune Neutropenia
- What is being tested?
- Mavorixafor
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- No sites listed yet
- Study dates
- Dec 2026to 30 Jan 2029
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 12 years and older
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- Diagnosis of acquired primary chronic neutropenia (CN) disorder ≥6 months prior to the screening visit (Week -2 up to Week 1) that is not attributable to medications, active or recent infections, or malignancy.
- On G-CSF for ≥6 months; stable dose prior to start of mavorixafor dosing.
- Most recent bone marrow examination, within 3 years, shows no evidence of malignancy/high risk of malignant transformation.
Who cannot join
- Participant is incapacitated and unable to comply with protocol-specific requirements.
- A diagnosis of any of the following:
- Aplastic anemia
- Warts, Hypogammaglobulinemia, Infections, and Myelokathexis (WHIM) syndrome
- CN other than CIN or AIN
- A medical or personal condition that may potentially compromise the safety of the participant, may preclude the participant's successful completion of the clinical study, or could, in the opinion of the Investigator or the Medical Monitor, interfere with the objectives of the study.
Show all 9Show fewer
- Participant is currently taking or has taken an investigational drug <30 days prior to the screening visit, or 5 half-lives, whichever is longer.
- Participant is pregnant or breastfeeding.
- Note: Other protocol-defined inclusion and exclusion criteria may apply.
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: A Phase 2b, Single-arm, Open-label, Multicenter Study to Evaluate the Safety and Tolerability of G-CSF Dosage Reduction With Mavorixafor in Participants With Acquired Primary Autoimmune and Idiopathic Chronic Neutropenia Disorders
The purpose of this study is to evaluate the safety and tolerability of G-CSF dosage reduction with mavorixafor in participants with autoimmune neutropenia (AIN) and chronic idiopathic neutropenia (CIN) disorders as assessed by the ability to safely reduce G-CSF dosage with mavorixafor treatment while maintaining clinically acceptable absolute neutrophil count (ANC) levels.
Read the detailed description
All participants will be receiving chronic G-CSF background therapy and will continue this pre-study background therapy, defined as the participant's current treatment regimen.
- Conditions
- Acquired Primary Autoimmune and Idiopathic Chronic Neutropenia Disorders, Chronic Neutropenia, Autoimmune Neutropenia, Chronic Idiopathic Neutropenia
- Being tested
- Mavorixafor
- Keywords
- G-CSF, Chronic neutropenia, Mavorixafor, X4P-001, Autoimmune neutropenia, Chronic idiopathic neutropenia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
MavorixaforDrug
Also called X4P-001
Mavorixafor will be administered per schedule specified in the arm description.
| Study group | Role | What they receive |
|---|---|---|
| Mavorixafor | Experimental | Participants will receive mavorixafor once daily orally for 52 weeks (starting from Week 4 through 56). Receives: Drug: Mavorixafor |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Participants With Treatment-emergent Adverse Events (TEAEs)
Measured: Up to Week 56
Percent Change in Average Daily G-CSF Dosage
Measured: Week 12 through Week 28 or 32
Percentage of Participants Achieving G-CSF Cessation
Measured: Week 28 or 32
Percentage of Participants Achieving G-CSF Dosage Reduction ≥75%
Measured: Week 28 or 32
Secondary outcomes (9)
Percentage of Participants Achieving G-CSF Dosage Reduction by ≥ 25%/≥ 50%
Measured: Week 12 through Week 28 or 32
Time to G-CSF Cessation
Measured: Week 4 through Week 28 or 32
Time to G-CSF Dosage Reduction of ≥25% or ≥50% or ≥75
Measured: Week 4 through Week 28 or 32
Change From Week 12 in Average Daily G-CSF Dosage at Week 28 or 32
Measured: Week 12, Week 28 or 32
Change From Week 12 in Average Daily G-CSF Frequency at Week 28 or 32
Measured: Week 12, Week 28 or 32
Change From Week 4 in Bone Pain up to Week 56, Assessed Using Patient-Reported Outcomes Measurement Information System Short Form (PROMIS SF) Pain Intensity Scale Score (Participants Aged 12 to <18 Years)
Measured: Week 4, up to Week 56
Change From Week 4 in Bone Pain up to Week 56, Assessed Using Functional Assessment of Chronic Illness Therapy (FACIT) Bone Pain Scale Score (Participants Aged ≥18 Years)
Measured: Week 4, up to Week 56
Change From Week 4 in Fatigue up to Week 56, Assessed Using PROMIS SF Fatigue Scale Score (Participants Aged 12 to <18 Years)
Measured: Week 4, up to Week 56
Change From Week 4 in Fatigue up to Week 56, Assessed Using FACIT-Fatigue Scale Score (Participants Aged ≥18 years)
Measured: Week 4, up to Week 56
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Oct 2026
- Study startDec 2026 (estimated)
- Primary completion30 Jan 2029 (estimated)
- Study completion30 Jan 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Acquired Primary Autoimmune and Idiopathic Chronic Neutropenia DisordersStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- X4 Pharmaceuticals
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Senior Vice President, Clinical Development, Study director, X4 Pharmaceuticals
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07902830
- Sponsor's protocol ID
- X4P-001-112
- Status last verified
- Oct 2026
- First submitted
- 20 Oct 2026
- Last updated
- 29 Oct 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 29 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 2b, Single-arm, Open-label, Multicenter Study to Evaluate the Safety and Tolerability of G-CSF Dosage Reduction With Mavorixafor in Participants With Acquired Primary Autoimmune and Idiopathic Chronic Neutropenia Disorders
- ClinicalTrials.gov ID
- NCT07902830
- Acronym / sponsor ID
- X4P-001-112
- Conditions
- Acquired Primary Autoimmune and Idiopathic Chronic Neutropenia Disorders, Chronic Neutropenia, Autoimmune Neutropenia, Chronic Idiopathic Neutropenia
- Keywords
- G-CSF, Chronic neutropenia, Mavorixafor, X4P-001, Autoimmune neutropenia, Chronic idiopathic neutropenia
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 40 participants (estimated)
- Lead sponsor
- X4 PharmaceuticalsIndustry (pharma, biotech, devices)
- Study start
- Dec 2026 (estimated)
- Primary completion
- 30 Jan 2029 (estimated)
- Study completion
- 30 Jan 2029 (estimated)
- First posted
- 29 Oct 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to evaluate the safety and tolerability of G-CSF dosage reduction with mavorixafor in participants with autoimmune neutropenia (AIN) and chronic idiopathic neutropenia (CIN) disorders as assessed by the ability to safely reduce G-CSF dosage with mavorixafor treatment while maintaining clinically acceptable absolute neutrophil count (ANC) levels.
Detailed description
All participants will be receiving chronic G-CSF background therapy and will continue this pre-study background therapy, defined as the participant's current treatment regimen.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Mavorixafor | Experimental | Drug: MavorixaforParticipants will receive mavorixafor once daily orally for 52 weeks (starting from Week 4 through 56). |
Who may qualify
- Ages
- 12 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (3 listed)
- Diagnosis of acquired primary chronic neutropenia (CN) disorder ≥6 months prior to the screening visit (Week -2 up to Week 1) that is not attributable to medications, active or recent infections, or malignancy.
- On G-CSF for ≥6 months; stable dose prior to start of mavorixafor dosing.
- Most recent bone marrow examination, within 3 years, shows no evidence of malignancy/high risk of malignant transformation.
Key exclusion criteria (9 listed)
- Participant is incapacitated and unable to comply with protocol-specific requirements.
- A diagnosis of any of the following:
- A medical or personal condition that may potentially compromise the safety of the participant, may preclude the participant's successful completion of the clinical study, or could, in the opinion of the Investigator or the Medical Monitor, interfere with the objectives of the study.
- Participant is currently taking or has taken an investigational drug <30 days prior to the screening visit, or 5 half-lives, whichever is longer.
- Participant is pregnant or breastfeeding.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| MavorixaforAlso: X4P-001Mavorixafor will be administered per schedule specified in the arm description. | Drug | Mavorixafor |
Primary outcome
Number of Participants With Treatment-emergent Adverse Events (TEAEs)
Time frame: Up to Week 56
Percent Change in Average Daily G-CSF Dosage
Time frame: Week 12 through Week 28 or 32
Percentage of Participants Achieving G-CSF Cessation
Time frame: Week 28 or 32
Percentage of Participants Achieving G-CSF Dosage Reduction ≥75%
Time frame: Week 28 or 32
9 secondary outcomes
Percentage of Participants Achieving G-CSF Dosage Reduction by ≥ 25%/≥ 50%
Time frame: Week 12 through Week 28 or 32
Time to G-CSF Cessation
Time frame: Week 4 through Week 28 or 32
Time to G-CSF Dosage Reduction of ≥25% or ≥50% or ≥75
Time frame: Week 4 through Week 28 or 32
Change From Week 12 in Average Daily G-CSF Dosage at Week 28 or 32
Time frame: Week 12, Week 28 or 32
Change From Week 12 in Average Daily G-CSF Frequency at Week 28 or 32
Time frame: Week 12, Week 28 or 32
Change From Week 4 in Bone Pain up to Week 56, Assessed Using Patient-Reported Outcomes Measurement Information System Short Form (PROMIS SF) Pain Intensity Scale Score (Participants Aged 12 to <18 Years)
Time frame: Week 4, up to Week 56
Change From Week 4 in Bone Pain up to Week 56, Assessed Using Functional Assessment of Chronic Illness Therapy (FACIT) Bone Pain Scale Score (Participants Aged ≥18 Years)
Time frame: Week 4, up to Week 56
Change From Week 4 in Fatigue up to Week 56, Assessed Using PROMIS SF Fatigue Scale Score (Participants Aged 12 to <18 Years)
Time frame: Week 4, up to Week 56
Change From Week 4 in Fatigue up to Week 56, Assessed Using FACIT-Fatigue Scale Score (Participants Aged ≥18 years)
Time frame: Week 4, up to Week 56
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Oct 2026.
- Individual participant dataSharing planned: No
Related trials for Acquired Primary Autoimmune and Idiopathic Chronic Neutropenia Disorders
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Senior Vice President, Clinical Development study director
X4 Pharmaceuticals
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Mavorixafor in people with Acquired Primary Autoimmune and Idiopathic Chronic Neutropenia Disorders and Chronic Neutropenia, run by X4 Pharmaceuticals.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 29 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Patient Affairs and Advocacy (857-529-5779, clinicaltrialinfo@x4pharma.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of Participants With Treatment-emergent Adverse Events (TEAEs) (time frame: Up to Week 56). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 Oct 2026.