How it is administered

Pegfilgrastim is given as a subcutaneous (under the skin) injection. It is available in several forms, including:

• Prefilled syringes for manual injection (6 mg/0.6 mL)
• On-body injector devices (for some brands)
• Prefilled autoinjectors (for some brands)

The usual adult dose is a single 6 mg injection once per chemotherapy cycle. For children weighing less than 45 kg, the dose is based on body weight. The injection is typically given at least 24 hours after chemotherapy and not within 14 days before the next chemotherapy session.

How it works

Pegfilgrastim is a type of medicine called a colony-stimulating factor. It works by stimulating your bone marrow to produce more neutrophils, which are a type of white blood cell that helps your body fight infections.

When you receive chemotherapy for cancer, your white blood cell count can drop, making you more vulnerable to infections. Pegfilgrastim binds to specific receptors on blood-forming cells in your bone marrow, encouraging them to grow and mature into healthy neutrophils. This helps reduce the risk of severe neutropenia (low neutrophil count) and the associated risk of infection and fever (febrile neutropenia).

The medication is designed to stay in your body longer than similar medicines, so you only need one injection per chemotherapy cycle. Your body clears pegfilgrastim mainly through the action of neutrophils, so as your white blood cell count recovers, the medication is naturally removed from your system.

Who Should take it

Pegfilgrastim is recommended for patients with non-myeloid cancers (cancers that do not start in the bone marrow) who are receiving chemotherapy that is likely to cause a significant drop in white blood cells and increase the risk of infection (febrile neutropenia).

It is used to help prevent infections in people who are at risk due to the effects of chemotherapy. Pegfilgrastim is also approved to increase survival in patients who have been acutely exposed to myelosuppressive doses of radiation. It is not used to treat existing infections, but rather to help prevent them by boosting white blood cell counts. For children, dosing is adjusted by weight, and its safety and effectiveness have been established in pediatric patients.

Who should not take it

Pegfilgrastim should not be used in patients who have had serious allergic reactions to pegfilgrastim, filgrastim, or other granulocyte colony-stimulating factors. Reactions can include anaphylaxis, a severe and potentially life-threatening allergic response.

It is also not indicated for patients with myeloid cancers (such as leukemia or myelodysplastic syndromes) because it could potentially stimulate the growth of these types of cancer cells. Additionally, it is not approved for mobilizing stem cells for transplantation. If you have sickle cell disease, caution is advised, as pegfilgrastim can trigger severe sickle cell crises. Always discuss your full medical history with your healthcare provider before starting this medication.

Commonly used with

Pegfilgrastim is commonly used alongside chemotherapy regimens for various cancers, including breast cancer, lung cancer, and lymphoma. It is not a chemotherapy drug itself, but is used to support patients during chemotherapy by reducing the risk of infection.

It may also be used with antibiotics if a patient develops an infection, but its primary role is prevention. It is not typically combined with other colony-stimulating factors.

Commonly tested with

Pegfilgrastim has been tested in combination with a variety of chemotherapy drugs, such as doxorubicin, docetaxel, and other agents used in the treatment of solid tumors and lymphomas. It has also been compared in studies to filgrastim, another colony-stimulating factor, to show similar effectiveness in reducing the duration of severe neutropenia.

It is not typically tested with other growth factors or stem cell mobilizers, as it is not approved for those uses.