Similarities and differences in the oncology drug approval process between FDA and European Union with emphasis on in vitro companion diagnostics.

Drug approval [U.S. Food and Drug Administration (FDA), or market authorization for the European Union's European Medicines Agency (EMA)] is the most significant regulatory milestone for any drug, as drugs can only be marketed after marketing approval by a health authority. This article focuses on the main regulatory aspects of the drug approval process in the European Union (EU) and the United States. Although the procedures, requirements, and timelines for drug approvals are different between the EU and the United States, several global harmonization efforts have been developed during the past few years to have more consistent regulatory procedures/outcomes in different parts of the world. One of the most different procedures/requirements among these regions is co-development, also known as in vitro companion diagnostic. In the United States, it is expected that for a drug that requires an in vitro diagnostic test to select the population to be treated, the companion diagnostic should be already/concomitantly approved by the FDA. In the EU, these requirements are not as stringent as in the United States. However, it is anticipated that in the very near future, legislation changes in the EU will lead to similar requirements for the companion diagnostics for EMA. In summary, although the principles, procedures, and requirements for drug approvals may differ between the United States and EMA, novel efforts to harmonize them are being considered and implemented, thereby leading to simpler global drug development. It is of outmost importance that drug developers understand and appreciate differences in regional regulations. Otherwise, lack of understanding may lead to rejection or delays in drug approvals for useful anticancer agents. See all articles in this CCR Focus section, "The Precision Medicine Conundrum: Approaches to Companion Diagnostic Co-development."