Filgrastim, a white blood cell stimulating product, has been shown to decrease the risk of infection and hospitalization as a result of chemotherapy-induced neutropenia. Filgrastim is removed (eliminated) from the body by 2 mechanisms viz excretion through urine and by binding to specific receptors on the surface of neutrophils (an important white blood cell which plays a pivotal role in protecting the body against various pathogens such as bacteria and virus). Due to the relatively short time it remains circulating in the blood, filgrastim requires up to two weeks of daily injections following each cycle of chemotherapy.

Neulastim^® is pegylated filgrastim i.e. a long-acting form of filgrastim which allows for once-per-chemotherapy cycle dosing. The process of pegylation increases the size of the drug (in this case filgrastim) which prevents its excretion in urine. This means that Neulastim^® can be eliminated only via the receptors on the neutrophils and its precursors (unlike filgrastim which also is eliminated in the urine). In a patient who receives chemotherapy the number of neutrophils are reduced and this allows Neulastim^® to remain in the blood for a longer period of time and continue to stimulate the formation of new neutrophils. As the number of neutrophils increases,  the levels of Neulastim^® reduces. This unique 'Self Regulating' mechanism of Neulastim^® allows for tailored protection which is unique to each patient i.e. Neulastim^® is present in the body as long as the neutrophil counts are below normal and once the number of neutrophils come back to normal, the drug is eliminated by the very cells whose multiplication it stimulated. In addition to reducing the inconvenience associated with daily injections of filgrastim, the simple, once- per-chemotherapy-cycle administration of Neulastim^® may increase adherence to treatment regimens and eliminate the potential for missed doses of filgrastim.

Data from two pivotal phase 3 studies in breast cancer patients demonstrated that a single dose of Neulastim^® was comparable to approximately 11 daily injections of filgrastim, in reducing both the duration of severe neutropenia and the frequency of febrile neutropenia. The clinical trials showed that Neulastim^® is as safe as filgrastim.

Sourced From:  Torque Communications Private Ltd