If you thought the FDA was going to make proving biosimilar interchangeability a piece of cake…think again. Shocking, we know. Much to the delight of those who manufacture originator biologics, the FDA released its fairly stringent biosimilar interchangeability guidance last week. Folks, it ain’t gonna be easy. In order for a branded prescription to be switched out for a biosimilar without a doctor’s thumbs up, interchangeability with the original product has to be proven with complex switching studies. Unfortunately for biosim makers, many studies currently underway do not meet these switching study requirements. Hooray for innovation! Bummer for affordability.