Yesterday, the Food and Drug Administration (“FDA”) announced the creation of the “Purple Book.” More formally known as the “Lists of Licensed Biological Products with Reference Product Exclusivity and Biosimilarity or Interchangeability Evaluations,” this is where FDA will list biological products—including any biosimilar and interchangeable biological products—licensed under the Public Health Service Act. Unlike FDA’s Orange Book, the Purple Book does not contain relevant patent information; instead, the Purple Book provides: (i) product and proprietary names, (ii) licensure dates, (iii) reference-product exclusivity expiration dates, and (iv) interchangeability and biosimilarity determinations. Biological products that are biosimilar and/or interchangeable will be listed under their respective reference products. Through the Purple Book, FDA will maintain—and periodically update—separate lists for those biological products regulated by the Center for Drug Evaluation and Research (“CDER”) and those regulated by the Center for Biologics Evaluation and Research (“CBER”).