Pronunciation: Zoll-REM-dee
Generic name: mavorixafor
Dosage form: oral capsule (100 mg)
Drug class: Other immunostimulants

Medically reviewed by Carmen Pope, BPharm. Last updated on Feb 11, 2025.

What is Xolremdi?

Xolremdi is used to treat WHIM syndrome in adults and children 12 years of age and older to increase the numbers of certain circulating blood cells (specifically mature neutrophils and lymphocytes). It is an oral capsule that is taken 1 time a day on an empty stomach.

Xolremdi gained FDA approval on 26 April 2024. There is no generic.

What is WHIM syndrome?

WHIM syndrome is a rare, genetic, disorder that affects the immune system. It's caused by a malfunction in the CXCR4/CXCL12 pathway, leading to white blood cells from being stuck in the bone marrow instead of circulating properly. This causes low levels of certain immune cells increasing a person's risk of infections.

People with  WHIM syndrome also commonly experience stubborn warts caused by HPV, have reduced antibody production, and face an increased risk of certain cancers.

How does Xolremdi work?

Xolremdi (mavorixafor) mechanism of action involves preventing the binding of a specific protein called SDF-1α/CXCL12 to the CXCR4 receptor. This receptor is involved in the movement of immune cells and by inhibiting this binding, Xolremdi helps prevent immune cells from becoming trapped in the bone marrow.

Clinical trials have shown that this is particularly important for WHIM syndrome, where mutations in the CXCR4 gene cause immune cells to be overly responsive to CXCL12, leading to their retention in the bone marrow. Xolremdi works in both normal and mutated CXCR4 variants associated with WHIM syndrome, promoting the release of immune cells from the bone marrow into the bloodstream.

Xolremdi belongs to the drug class called CXC chemokine receptor 4 antagonists. 

Xolremdi side effects

The most common side effects of Xolremdi are:

• Low platelet counts (thrombocytopenia)
• A rash, such as pityriasis (a rash that often begins as an oval spot on the face, chest, abdomen, or back)
• Nasal congestion, sneezing, and stuffiness
• Nosebleeds
• Vomiting
• Dizziness.

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.

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Serious side effects and warnings

Xolremdi may cause the following serious side effects. 

Harm to an unborn baby. Xolremdi may harm a developing baby. Females who can get pregnant should use effective contraception while taking Xolremdi and for 3 weeks after the last dose.

QTc interval prolongation. Clinical trials have reported that Xolremdi 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 Xolremdi.

Drug interactions. Xolremdi 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.

Before taking

Xolremdi should not be taken by people with severe kidney disease, end-stage kidney disease, or moderate to severe liver disease.

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

• Have allergies
• Have preexisting heart disease, such as an arrhythmia or QTc prolongation
• Take other medications
• Have low platelet levels
• Have skin conditions
• Have frequent nose bleeds
• Have liver or kidney disease
• Are pregnant, may become pregnant, or intend to become pregnant
• Are breastfeeding.

Pregnancy

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

Xolremdi may cause fetal harm and abnormal placental development. Females with childbearing potential should use effective contraception while receiving Xolremdi and for 3 weeks after the last dose. If you inadvertently become pregnant while receiving Xolremdi, tell your doctor right away.

Breastfeeding

You should not breastfeed while taking Xolremdi 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 Xolremdi?

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

• Take in the morning on an empty stomach, after an overnight fast and at least 30 minutes before you eat any food.

Xolremdi dosing information for WHIM syndrome

Your dosage of Xolremdi depends on your weight.

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

What should I avoid while taking Xolremdi?

Advise eating or drinking products with grapefruit, as grapefruit is a strong CYP3A4 inhibitor and may increase the risk of side effects from Xolremdi.

What other drugs will affect Xolremdi?

Other drugs may interact with Xolremdi, 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 Xolremdi.
• St. John’s Wort, as it may reduce the efficacy of Xolremdi.
• 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. See the Xolremdi Package Insert for more information.

Storage

Store Xolremdi 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

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

Xolremdi is manufactured by X4 Pharmaceuticals, Inc., whose headquarters are in Boston, Massachusetts, USA. Their 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.

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