Dr Georgia Demetriou tells us about the new biosimilar to filgrastim, called tbo-filgrastim, that has recently been registered for use in South Africa.
Filgrastim, or short-acting granulocyte colony-stimulating factor (G-CSF), is used to decrease the risk of infection during chemotherapy. It can be given 24 hours after chemotherapy as a preventative measure, or in response to a low neutrophil white blood cell count.
It can also be used to decrease the risk of infection during a bone marrow transplant, after the stem cells are infused, and in preparation of a bone marrow transplant, to raise the white cell count for leukapheresis, improving the chances of getting a good stem cell harvest.
Filgrastim can also be used to treat severe chronic neutropenia, requiring longer periods of treatment, or in the setting of exposure to radiation with a significant drop in the neutrophil count.
It also decreases the risk of infection, but doesn’t prevent all infections that may develop during or after chemo. So, if as a patient, you develop signs of infection, such as fever, chills, rash, sore throat, diarrhoea, redness, swelling, or pain around a cut or sore, please call your doctor.
This new biosimilar is a short-acting recombinant form of G-CSF and is a biosimilar to filgastrim. It has recently been registered in South Africa for use where it is necessary to reduce the duration of severe neutropenia in patients, with certain types of cancer which are non-myeloid malignancies and who are receiving chemotherapy that affects and suppresses the bone marrow.
What is a biosimilar?
Unlike generic medicines in which the active ingredients are identical to the reference small molecule drug, biosimilars will not be identical to the reference biologics. This is due to processes associated with translating biologics from living cells in the laboratory to mass-production molecules.
Biosimilars can only be highly similar to the reference product they are designed to resemble, as there is no way to make identical copies of biologics. The objective of biosimilars is to provide a process of simplification, designed to reduce production costs and encourage competition.
The approval process for biosimilars, to come to market, requires that there be no clinically meaningful differences between the biosimilar product and reference product in terms of safety, efficacy, purity, and potency.
The demonstration of biosimilarity needs to be demonstrated in a clinical trial. The concept of interchangeability exists when we discuss biosimilars. This is a higher requirement where there is the expectation of the same clinical results in any given patient for a product that is administered more than once, and no additional risk to safety or diminished efficacy as a result of switching or alternating the biosimilar and the originator.
How is a G-CSF administered?
Filgrastim or tbo-filgrastim may be given to you by a nurse or other healthcare providers, or you may be told to inject the medication at home.
If you’ll be injecting at home, inject the medication at about the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you don’t understand.
Use filgrastim or tbo-filgrastim exactly as directed. Don’t use more or less of it, or use it more often than prescribed by your doctor.
If you’ll be injecting filgrastim or tbo-filgrastim yourself, a healthcare provider will show you how to inject the medication. Be sure that you understand these directions. Ask your healthcare provider if you have any questions about where on your body you should inject; how to give the injection; and how to dispose of used needles and syringes after you inject. Depending on how your body reacts to the medication, the dose may be increased or decreased.
Don’t shake vials or syringes containing filgrastim or tbo-filgrastim. Vials and syringes that look foamy, cloudy, or discoloured shouldn’t be used. This medication should be kept in the container it came in, tightly closed, and out of reach of children. Filgrastim and tbo-filgrastim should be stored in the refrigerator but should not be placed in the freezer. Filgrastim may be kept at room temperature for up to 24 hours but should be kept away from direct sunlight. Tbo-filgrastim may be kept at room temperature for up to five days but should be protected from light.
Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people can’t consume them. However, you shouldn’t flush this medication down the toilet. Instead, the best way is to return it to your oncology pharmacist for appropriate disposal.
MEET OUR EXPERT – Dr Georgia Demetriou
Dr Georgia Demetriou is a medical oncologist at the Wits Oncology Donald Gordon Medical Centre. She is passionate about new developments and research in medical oncology and believes strongly in multi-disciplinary care. Her areas of special interest include endocrine, gastrointestinal and breast tumours. She has been involved as an investigator in a number of clinical trials.