In a decision that evoked a collective sigh of relief from brand drug makers, the U.S. Court of Appeals for the Federal Circuit held that a patent term extension under 35 U.S.C. §156 may be applied to a patent that is subject to a terminal disclaimer under 35 U.S.C §253. Merck & Co. v. Hi-Tech Pharmacal Co., Case No. 06-1401 (Fed. Cir., Mar. 29, 2007) (Linn, J.).
Merck owns U.S. Patent No. 4,797,413, covering dorzolamide, the active ingredient in TRUSOPT®, a drug used to treat glaucoma. The ’413 patent issued from a continuation-in-part application that claims priority from Merck’s U.S. Patent No. 4,677,115. During prosecution of the ’413 patent, the patent examiner rejected the claims for "obviousness-type double patenting," explaining that the claims were not patentably distinct from those of the earlier issued ’115 patent. To overcome the rejection, Merck filed a terminal disclaimer, disclaiming the terminal part of any patent beyond June 30, 2004.
The FDA approved Merck’s New Drug Application (NDA) for TRUSOPT® in 1994, after several years of FDA regulatory review. Due to the lengthy review process, the FDA granted Merck a patent term extension under § 156, thereby extending the term of the ’413 patent to April 28, 2008. Section 156 was enacted as part of the Hatch-Waxman Act and allows NDA holders to choose one patent for patent term extension per approved drug. After Hi-Tech filed Abbreviated New Drug Applications (ANDAs) for generic versions, Merck sued Hi-Tech for infringement of the ’413 patent. As its only defense, Hi-Tech asserted that the patent term extension on the ’413 patent was invalid due to the Merck’s voluntary terminal disclaimer. The district court was not impressed and entered final judgment on the pleadings in Merck’s favor and enjoined Hi-Tech from selling generic dorzolamide products until expiration of the ’413 patent. Hi-Tech appealed.
On appeal, the Federal Circuit noted that "the language of Section 156 is unambiguous and fulfills a purpose unrelated to and not in conflict with that of Section 253." The Court pointed out that § 156 enumerates specific conditions under which a patent term "shall be extended," none of which concerns terminal disclaimers. The Court further noted consistency between the legislative history and the mandatory language of §156. The Court also contrasted §156 to §154, which excludes patents in which a terminal disclaimer has been filed from the benefit of a term adjustment for U.S. Patent and Trademark Office (USPTO) delays, noting that §156 contains no such exclusionary language. Finally, the Court explained that § 156 and § 253 are compatible. The purpose of the terminal disclaimer remains fulfilled by virtue of the fact that the date from which any Hatch-Waxman extension is computed is the terminally disclaimed date. At the same time, the purpose of the patent term extension, which is restoration of some of the patent term lost due to regulatory review, also is satisfied.
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