Abstract
First biosimilars of monoclonal antibodies have recently been approved in oncology. Biosimilars enable economic competition, alleviate the financial burden for insurances, and may facilitate access to these drugs in low-income countries. Biosimilars are not completely identical to the original drug. The approval of biosimilars is only partially based on results of randomized clinical studies. In the introduction phase of new biosimilars, this can lead to uncertainties for patients and physicians. Based on the current clinical data and experiences, biosimilars of monoclonal antibodies in oncology show no significant differences in pharmacokinetics, efficacy, and safety in comparison to the patented originals. Scientific medical societies recommend the use of biosimilar monoclonal antibodies and support switching in long-term treatments. However, the use of biosimilars for off-label indications requires additional attention towards efficacy and safety. Active counselling of the patient by the treating physician is the most important step in the informed consent process, especially when switching from an original to a biosimilar. Careful documentation of the prescribed drug and enhanced pharmacovigilance are recommended for the use of biosimilars.