U.S. Patent Act
..Part II. Patentabililty of Inventions and Grant of Patents
....Chapt. 14. Issue of Patent
Notwithstanding the provisions of section 154 [35 USCS Sect. 154], the term of a patent which encompasses within its scope a composition of matter or a process for using such composition shall be extended if such composition or process has been subjected to a regulatory review by the Federal Food and Drug Administration pursuant to the Federal Food, Drug, and Cosmetic Act [21 USCS Sects. 301 et seq.] leading to the publication of regulation permitting the interstate distribution and sale of such composition or process and for which there has thereafter been a stay of regulation of approval imposed pursuant to section 409 of the Federal Food, Drug, and Cosmetic Act [21 USCS Sect. 348] which stay was in effect on January 1, 1981, by a length of time to be measured from the date such stay of regulation of approval was imposed until such proceedings are finally resolved and commercial marketing permitted. The patentee, his heirs, successors or assigns shall notify the Commissioner of Patents and Trademarks within ninety days of the date of enactment of this section [enacted Jan. 3, 1983] or the date the stay of regulation of approval has been removed, whichever is later, of the number of the patent to be extended and the date the stay was imposed and the date commercial marketing was permitted. On receipt of such notice, the Commissioner shall promptly issue to the owner of record of the patent a certificate of extension, under seal, stating the fact and length of the extension and identifying the composition of matter or process for using such composition to which such extension is applicable. Such certificate shall be recorded in the official file of each patent extended and such certificate shall be considered as part of the original patent, and an appropriate notice shall be published in the Official Gazette of the Patent and Trademark Office.