Pronunciation: MAV-or-ix-a-for
Generic name: mavorixafor
Brand name: Xolremdi
Dosage form: oral capsule (100 mg)
Drug class: Other immunostimulants

Medically reviewed by Carmen Pope, BPharm. Last updated on May 12, 2025.

What is Mavorixafor?

Mavorixafor is used to treat WHIM syndrome (Warts, Hypogammaglobulinemia, Infections, and Myelokathexis syndrome) in adults and children 12 years of age and older. It is an oral capsule that is taken once a day.

Mavorixafor gained FDA approval on 26 April 2024 under the brand name Xolremdi. There is no generic.

Mechanism. How does mavorixafor work?

Mavorixafor works by targeting the CXCR4 receptor, preventing the binding of another substance, called stromal-derived factor-1α (SDF-1α)/CXC Chemokine Ligand 12 (CXCL12). The SDF-1/CXCR4 system is crucial for the movement of leukocytes (a type of white blood cell) to and from the bone marrow. Mavorixafor blocks the response to wild-type and mutated CXCR4 variants associated with WHIM syndrome, increasing levels of circulating mature neutrophils and lymphocytes.

Mavorixafor belongs to the drug class called oral CXCR4 antagonists.

Side effects

The most common side effects of mavorixafor are:

• low platelet levels
• a rash
• nasal congestion, sneezing, stuffiness, and nosebleeds
• vomiting
• dizziness.

Serious side effects and warnings

Mavorixafor may cause the following serious side effects:

• QTc interval prolongation. Clinical trials have reported that mavorixafor can prolong the QTc interval. Your healthcare provider should correct any risk factors that can be corrected (such as low potassium levels), assess your QTc before starting treatment, and monitor it throughout treatment. The risk of QTc prolongation is higher in those receiving other QTc prolonging drugs, such as haloperidol, amiodarone, sotalol, or ondansetron, or taking other medications that increase blood levels of mavorixafor
• Drug interactions. Mavorixafor should not be given with other medications that are highly dependent on CYP2D6 liver enzymes for clearance, such as fluoxetine or amitriptyline. Tell your healthcare provider about all the medications you take
• Harm to an unborn baby. Mavorixafor may harm a developing baby. Females who can get pregnant should use effective contraception while taking mavorixafor and for 3 weeks after the last dose.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to X4 Pharmaceuticals, Inc. at 1-866-MED-X4MI (1-866-633-9464) or the FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Related/similar drugs

Before taking

Do not take mavorixafor if you have severe or end-stage kidney disease, or moderate to severe liver disease.

Before taking mavorixafor, tell your healthcare provider about all your medical conditions, including if you:

• have any allergies to mavorixafor, Xolremdi, or any of the inactive ingredients in the capsule
• have preexisting heart conditions, such as an arrhythmia or QTc prolongation
• take any other medications
• have low platelet levels
• have skin conditions
• have frequent nose bleeds
• have liver or kidney disease
• are pregnant or intending to become pregnant
• are breastfeeding or intending to breastfeed.

Pregnancy

You may need to have a negative pregnancy test before starting mavorixafor. Do not take this medication if you are pregnant.

Mavorixafor may harm an unborn baby and affect the development of its placenta. Females with childbearing potential should use effective contraception while receiving mavorixafor and for 3 weeks after the last dose. If you become pregnant while receiving mavorixafor, tell your doctor right away.

Breastfeeding

You should not breastfeed while taking mavorixafor and for 3 weeks after the last dose. Talk to your healthcare provider about the best way to feed your baby.

How do I take mavorixafor?

Mavorixafor is a capsule that is taken 1 time a day before breakfast.

• Take it as soon as you wake up, at least 30 minutes before you eat food.

Dosing information

Mavorixafor dosage for WHIM syndrome: 

• More than 50 kg: 400 mg (4 capsules) orally once daily.
• Less than or equal to 50 kg: 300 mg (3 capsules) orally once daily.

What should I avoid while taking mavorixafor?

Advise eating or drinking products that contain grapefruit, because grapefruit is a strong CYP3A4 inhibitor and may increase the risk of side effects from mavorixafor.

What other drugs will affect mavorixafor?

Other drugs may interact with mavorixafor, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using. Especially tell your doctor if you take:

• Goldenseal or grapefruit as it may increase the risk of side effects from mavorixafor.
• St. John’s Wort, as it may reduce the efficacy of mavorixafor.
• Medications that are highly dependent on CYP2D6 enzymes for clearance, such as fluoxetine or amitriptyline
• Medications that cause low potassium, such as diuretics
• QTc prolonging drugs, such as haloperidol, amiodarone, sotalol, or ondansetron
• Strong CYP3A4 inhibitors, such as itraconazole
• CYP3A4 substrates, such as midazolam
• P-gp substrates, such as digoxin or metformin.

This is not a complete list of interactions. Talk to your healthcare provider or pharmacist about drug interactions. 

Storage

Store mavorixafor capsules in the refrigerator at 2°C to 8°C (36°F to 46°F). Keep it in the original container to protect it from moisture and tightly closed.

Ingredients

Xolremdi ingredients

Active: mavorixafor 100mg.

Inactive: colloidal silicon dioxide, croscarmellose sodium, dibasic calcium phosphate dihydrate, microcrystalline cellulose, sodium lauryl sulfate, and sodium stearyl fumarate.

Hard gelatin capsule: FD&C Blue #2, gelatin, and titanium dioxide.

Black Ink: ammonium hydroxide 28%, ferrosoferric oxide/black iron oxide (E172), isopropyl alcohol, n-butyl alcohol, propylene glycol, and shellac glaze in ethanol.

Available as 100 mg capsules.

Manufacturer

Mavorixafor is manufactured by X4 Pharmaceuticals, Inc., under the brand name Xolremdi. X4 Pharmaceuticals Inc. is based in Boston, Massachusetts, USA, and its focus is on rare diseases and other limited treatment opportunities.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer