Equally safe and effective alternatives to biological reference products, biosimilars, can lead to lowered treatment costs and higher patient access. With the arrival of biosimilars in the treatment of cancer (i.e., trastuzumab, rituximab, bevacizumab), it is important that oncologists gain confidence to adopt biosimilars in clinical practice. This article, the first in a series of two, emphasizes the need for biosimilars to create a competitive and sustainable biologicals market, highlights key concepts of the regulatory approval pathway of biosimilars, explains what key challenges biosimilars are facing, and what actions have been undertaken in Belgium to increase their use. We conclude with some recommendations.

(BELG J MED ONCOL 2020;14(6):280-5)