Biologics are large protein or polypeptide molecules produced by living organisms, which largely determine the efficiency of modern anticancertherapy. Biological products that destroy cancer cells and protect normal patient tissue led to progress in the treatment of breast cancer, colon cancer, kidney cancer, malignant lymphomas and other diseases. But the high cost and complexity of production limit their use. The expiration of patent protection for a number of biological products resulting to the possibility of reduces their costs when issuing an alternative manufacturer. At the same time, biosimilars are produced by living cells (as the original protein molecules), which led to serious difficulties in reaching their identity. The European Union has developed special registration rules for these preparations in order to avoid lack of efficacy or increased toxicity. They include regulations to determine the quality of biological products, requirements for pre-clinical and clinical studies, according to its specific characteristics, as well as the requirements for pharmacovigilance. Implementation of such a strategy has to register in the EU several biosimilars of granulocyte colonytimulating factor. For one of them – Zarzio – in several clinical studies fully comparable efficacy and tolerability with the original preparation was shown, thus providing a significant reduction of treatment cost with equal efficacy and toxicity.