Document Type


Publication Date



Congress created 180-day exclusivity for generic drug applicants in the 1984 Hatch-Waxman amendments to the Federal Food, Drug, and Cosmetic Act (FDCA) and amended it substantially in the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (MMA). The core concept of this exclusivity as it has been applied by FDA and the courts is that the first generic drug applicant to challenge an innovator's patent is entitled to six months of exclusivity against subsequent patent challengers for the same innovator drug. The 180-day exclusivity provision is governed by sections 505(j)(5)(B)(iv) and 505(j)(5)(D) of the FDCA, and it is intended to encourage generic applicants to challenge innovator patents. Although the basic idea is simple and the language enacted in 1984 was correspondingly brief, over the years the provision has given rise to a substantial number of interpretive disputes, both at the agency and in the courts. The courts are still grappling with interpretation of the 1984 provision, and it is already apparent that the amended language will trigger additional disputes. An earlier article in this journal traced the history of the 180-day exclusivity provision from 1984 through its amendment in 2003 and court cases in 2004.

This article updates the earlier piece through the end of 2006 but is arranged by issue rather than in a chronology. Part II presents the original and amended statutory language. For the most part, the amended language applies only to abbreviated new drug applications (ANDAs) filed after December 8, 2003, provided there was no paragraph IV certification to the reference drug prior to that date. We refer to these as "new ANDAs" and to all other ANDAs as "old ANDAs." Part III presents the interpretive issues that have been addressed by FDA and/or the courts and describes their resolution with respect to old ANDAs and, where different, new ANDAs.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.