Class: Biological Therapy

Generic Name: Filgrastim-sndz

Trade Name: Zarxio™

For which conditions is this drug approved? Zarxio is approved to decrease the incidence of infection in patients with a low neutrophil (type of white blood cell that helps fight infection) count due to cancer treatment, a condition called neutropenia.

What is the mechanism of action? Zarxio is a man-made form of a substance produced by the body known as granulocyte colony-stimulating factor (G-CSF). G-CSF stimulates the growth of neutrophils, a type of white blood cell that helps the body fight against infection. Man-made forms of naturally occurring substances are known as biosimilars.

How is Zarxio typically given (administered)? Zarxio is given by intravenous (IV) infusion or injection under the skin by a doctor or nurse. Your doctor may also decide that you can give yourself Zarxio injections under the skin at home or your caregiver can give you the injections. If you’re receiving Zarxio at home, see the detailed “Instructions for Use” that comes with your Zarxio for information on how to prepare and inject a dose.

How are patients typically monitored? During treatment with Zarxio, patients will be monitored for an enlarged spleen or ruptured spleen; patients who report left upper abdominal or shoulder pain should have their spleens examined. Patients will also be monitored for acute respiratory distress syndrome (ARDS); signs and symptoms include fever and lung infiltrates (pus, blood, or protein in the lungs) or respiratory distress. Patients will also be watched for serious allergic reactions and have blood tested regularly to check for blood disorders.

What are the common (occur in 30% or more of patients) side effects of treatment with Zarxio?

• Low platelet count
• Nausea
• Fever

What are the less common (occur in 10% to 29% of patients) side effects of treatment with Zarxio?

• Chest pain
• Fatigue
• Pain
• Back pain
• Bone pain
• Dizziness
• Cough
• Difficult or labored breathing
• Rash

This is not a complete list of side effects. Some patients may experience other side effects that are not listed here. Patients may wish to discuss with their physician the other less common side effects of this drug, some of which may be serious.

Some side effects may require medical attention. Other side effects do not require medical attention and may go away during treatment. Patients should check with their physician about any side effects that continue or are bothersome.

What can patients do to help alleviate or prevent discomfort and side effects?

• Tell your doctor if you have a sickle cell disorder.
• Tell your doctor if you are receiving radiation therapy.
• Tell your doctor if you are allergic to latex. The needle cap on the prefilled syringe contains natural rubber (derived from latex). Do not handle the prefilled syringe if you are allergic to latex.
• Tell your doctor about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.
• If you miss a dose of Zarxio, talk to your doctor about when you should give your next dose.

Are there any special precautions patients should be aware of before starting treatment?

• Do not take Zarxio if you have had a serious allergic reaction to human G-CSFs such as filgrastim or pegfilgrastim products.
• Tell your doctor if you are pregnant or plan to become pregnant. It is not known if Zarxio will harm your unborn baby.
• Tell your doctor if you are breastfeeding or plan to breastfeed. It is not known if Zarxio passes into your breast milk.

When should patients notify their physician? Tell your doctor if you have signs or symptoms of:

• Spleen rupture. Call your doctor right away if you have pain in the left upper stomach area or your left shoulder.
• Acute respiratory distress syndrome. Call your doctor or get emergency medical help right away if you have shortness of breath with or without a fever, trouble breathing, or a fast rate of breathing.
• Serious allergic reactions. Call your doctor or get emergency help right away if you develop a rash over your whole body, shortness of breath, wheezing, dizziness, swelling around your mouth or eyes, fast heart rate, and sweating.
• Sickle cell crises. If you have a sickle cell disorder and take Zarxio, call your doctor if you experience pain or difficulty breathing.
• Capillary leak syndrome (a condition where fluid leaks from blood vessels into your body’s tissues). Get emergency medical help right away if you develop any of the following symptoms: swelling or puffiness and are urinating less often; trouble breathing; swelling of your stomach area; a feeling of fullness; dizziness or feeling faint; a general feeling of tiredness.
• Decreased platelet count. Tell your doctor if you have unusual bleeding or bruising.
• Inflammation of your blood vessels (cutaneous vasculitis). Tell your doctor if you develop purple spots or redness of your skin.

What is a package insert?

A package insert is required by the FDA and contains a summary of the essential scientific information needed for the safe and effective use of the drug for healthcare providers and consumers.  A package insert typically includes information regarding specific indications, administration schedules, dosing, side effects, contraindications, results from some clinical trials, chemical structure, pharmacokinetics and metabolism of the specific drug. By carefully reviewing the package insert, you will get the most complete and current information about how to safely use this drug. If you do not have the package insert for the drug you are using, your pharmacist or physician may be able to provide you with a copy.