Granulocyte colony stimulating factors: how different are they? How to make a decision?

Two granulocyte colony stimulating factors (G-CSFs) are available for clinical use in Europe: filgrastim (Neupogen) and lenograstim (Granocyte). The purpose of this literature review is to study how they differ, the clinical implications of these differences (especially in terms of efficacy) and the economic impact of these differences. From a chemical point of view the two molecules are not identical. Their amino acid sequence is different and one is glycosylated, whereas the other is not. The important question to ask is what these structural differences mean for the patient. It appears that glycosylation has important consequences in terms of efficacy. Several recent comparative studies, both in vitro and in vivo, in animals and in humans, reinforce this idea which was often shared intuitively by physicians. In economical terms, in hospitals where the exact dosages are used (150 microg/m2 or 19.2 million units (MU)/m2 for Granocyte, and 5 microg/kg or 0.5 MU/kg for Neupogen), the choice of G-CSF must be made according to the daily cost of treatment which, for an average patient, means comparing the price of 325 microg of Neupogen and of 255 microg of Granocyte. This is in fact equal to comparing the price per MU of each product. In hospitals where one vial per patient per day is used whatever be their weight or body surface area, the price per MU and the price per vial should be considered together, puting into perspective the potential therapeutic benefit for patients, one vial of Granocyte 34 containing more MU than one vial of Neupogen 30.