Zarzio - filgrastim

What is Zarzio?

Zarzio is a solution for injection or infusion (drip into a vein) into a pre-filled syringe that contains the active substance filgrastim (30 or 48 million units).

Zarzio is a "biosimilar" medicine, meaning that it is similar to a biological medicine already authorized in the European Union (EU) that contains the same active substance (also called "reference medicine"). The reference medicine for per Zarzio is Neupogen. For more information on biosimilar medicines, see the questions and answers by clicking here.

What is Zarzio used for?

Zarzio is used to stimulate the production of white blood cells in the following situations:

to reduce the duration of neutropenia (low levels of neutrophils, a type of white blood cell) and the incidence of febrile neutropenia (neutropenia with fever) in patients undergoing chemotherapy (treatment of a tumor) cytotoxic (cell destroyer);
to reduce the duration of neutropenia in patients undergoing treatment to destroy bone marrow cells before a transplant of the same (as in some leukemic patients) if they are at risk of long-term severe neutropenia;
to increase neutrophil levels and reduce the risk of infection in patients with neutropenia who have a history of serious and repeated infections;
to treat persistent neutropenia in patients with advanced human immunodeficiency virus (HIV) infection, with a view to reducing the risk of bacterial infections when other treatments are inadequate.

Zarzio can also be used in patients who are about to donate stem cells for a transplant, to help them release these cells from the bone marrow.

The medicine can only be obtained with a prescription.

How is Zarzio used?

Zarzio is given by subcutaneous injection or intravenous infusion. The method of administration, dosage and duration of treatment depend on the reason for its use, the patient's body weight and the response to treatment. Zarzio is generally given in a specialized treatment center, although patients who are injected under the skin can inject it themselves, provided they are properly trained. For more information, see the package leaflet.

How does Zarzio work?

The active substance in Zarzio, filgrastim, is very similar to a human protein called granulocyte colony stimulating factor (G-CSF). Filgrastim is produced by a method known as "recombinant DNA technology": it derives from a bacterium, in which a gene (DNA) has been grafted which makes it able to produce filgrastim. The substitute acts similarly to the naturally produced G-CSF factor, stimulating the bone marrow to produce more white blood cells.

How has Zarzio been studied?

Zarzio has undergone studies aimed at demonstrating its similarity to the reference preparation, Neupogen.

Four studies looked at blood neutrophil levels in a total of 146 healthy volunteers who received Zarzio or Neupogen. Studies have observed the effects of single and repeated administration of various doses of the medicine, given by subcutaneous injection or intravenous infusion. The main measure in these studies was neutrophil count during the first 10 days of treatment.

What benefit has Zarzio shown during the studies?

During the studies, Zarzio and Neupogen produced similar increases in neutrophil counts in healthy volunteers. This was considered sufficient to demonstrate that the benefits of Zarzio are comparable to those of the reference medicine.

What is the risk associated with Zarzio?

The most common side effect with Zarzio (in more than 1 patient in 10) is musculoskeletal pain (pain in the muscles and bones). In more than 1 in 10 patients other side effects may be observed, depending on the disease for which Zarzio is used. For the full list of all side effects reported with Zarzio, see the Package Leaflet.

Zarzio should not be used in people who may be hypersensitive (allergic) to filgrastim or any of the other ingredients.

Why has Zarzio been approved?

The Committee for Medicinal Products for Human Use (CHMP) considered that, based on the provisions of European Union legislation, Zarzio demonstrated quality, safety and efficacy characteristics similar to those of Neupogen. The CHMP is therefore of the opinion that, as in the case of Neupogen, the benefits outweigh the identified risks. The Committee recommended that Zarzio be given marketing authorization.