Orange Book Transparency Act of 2020 This bill modifies requirements for the Food and Drug Administration (FDA) to list and publish drug patent and exclusivity information. Specifically, the FDA must include on its list certain patent information and must specify each drug exclusivity period that has not concluded. The holder of an approved drug application must notify the FDA when a listed patent is invalidated by a court or by the Patent Trial and Appeal Board. The FDA must remove invalidated patents from its list, subject to the 180-day drug exclusivity period.