Patent term extensions for human drugs under the US Hatch-Waxman Act

Abstract

The US Drug Price Competition and patent Term Restoration Act of 1984 was a major revision to US pharmaceutical law. A significant provision of that law was the ability, under specific circumstances, to obtain an extension of the term of a patent that claims a new drug. The determination of eligibility for a patent extension is a complex matter that has been subject to differing interpretations by the courts and regulatory agencies. This article reviews the circumstances under which a patent can be extended, how an application for extension is submitted, and how the term of extension is calculated. A case study is presented to further illustrate the procedures. By limiting when a generic product can be launched, the determination of whether a patent is eligible for a patent term extension can have a major economic impact on both the innovator company and generic competitors. An understanding of patent term extension eligibility is a critical part of the life-cycle analysis of pharmaceuticals.