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Hatch-Waxman Patent Term Extension May Be Applied to a Patent Subject to a Terminal Disclaimer

March 29, 2007
Main Ph.D., Denise

Decision icon Decision

Last Month at the Federal Circuit - April 2007

Judges: Linn (author), Friedman, Plager

[Appealed from: D.N.J., Judge Cooper]

In Merck & Co. v. Hi-Tech Pharmacal Co., No. 06-1401 (Fed. Cir. Mar. 29, 2007), the Federal Circuit affirmed the district court’s holding that a patent term extension under the Hatch-Waxman Act, 35 U.S.C. § 156, may be applied to a patent subject to a terminal disclaimer filed to overcome an obviousness-type double-patenting rejection.

Merck & Company, Inc. (“Merck”) is the owner of U.S. Patent No. 4,797,413 (“the ’413 patent”), filed on June 26, 1987, which covers the drug dorzolamide, a carbonic anhydrase inhibitor, marketed by Merck under the trademark TRUSOPT®. During prosecution of the ’413 patent, the applicants filed a terminal disclaimer under 35 U.S.C. § 253 to overcome an obviousness-type double-patenting rejection over an earlier Merck patent, U.S. Patent No. 4,677,115 (“the ’115 patent”), which issued on June 30, 1987. Pursuant to the terminal disclaimer, any term of the ’413 patent extending beyond June 30, 2004 (seventeen years from the ’115 patent issuance), was relinquished.

Following the 1994 enactment of the Uruguay Round Agreement Act (“URAA”), the term of a patent in force was extended to the greater of twenty years from the filing date or seventeen years from the date of issue. As provided by the new law, the expiration dates of both the ’115 patent and the ’413 patent were extended to December 12, 2004 (twenty years after the filing date of the ’115 patent).

After the FDA’s regulatory review and approval of TRUSOPT®, Merck listed the ’413 patent in the Orange Book, providing notice that TRUSOPT® was covered by a patent as required by the FDA. Merck then requested and was granted from the PTO a Hatch-Waxman extension pursuant to 35 U.S.C. § 156, resetting the expiration date of the ’413 patent to April 28, 2008. Section 156 provides for the patent term of a patent listed in the Orange Book to be extended for the period of time the related product is delayed from the market by the FDA’s regulatory review.

On January 18, 2006, Merck sued Hi-Tech Pharmacal Company, Inc. (“Hi-Tech”), alleging infringement of the ’413 patent after Hi-Tech filed two ANDAs seeking FDA approval to market dorzolamide as eye drops before the expiration of the ’413 patent. Hi-Tech filed a motion to dismiss on the ground that the ’413 patent was unenforceable, having expired on December 12, 2004. Merck cross-moved for judgment that the terminal disclaimer did not disclaim the Hatch-Waxman term extension.

Denying Hi-Tech’s motion to dismiss and granting Merck’s motion for judgment on the pleadings, the district court enjoined Hi-Tech from marketing its generic dorzolamide product until April 28, 2008, the expiration date of the ’413 patent.

On appeal, the Federal Circuit analyzed the language of § 156, explaining that § 156 is silent as to whether a patent with a terminal disclaimer is excluded from the benefit of a Hatch-Waxman extension, yet § 154 explicitly states that the patent will not benefit from patent term adjustment for PTO delay. Thus, the Court concluded that it can be inferred that § 156 does not exclude the benefit of a Hatch-Waxman extension. In support of its conclusion, the Court cited the ruling in Leatherman v. Tarrant County Narcotics Intelligence & Coordination Unit, 507 U.S. 163, 168 (1993), where the Supreme Court held that an express requirement in a federal rule not included in a later federal rule indicates that the later federal rule does not have the same requirement. Additionally, the Court noted that “the mandate in § 156 that the patent term shall be extended if the requirements enumerated in that section are met, support[s] the conclusion that a patent term extension under § 156 is not foreclosed by a terminal disclaimer.” Slip op. at 9 (emphasis in original).

Rejecting Hi-Tech’s argument that to allow the Hatch-Waxman extension was to nullify the terminal disclaimer, the Federal Circuit found that there was no conflict between the terminal disclaimer under § 253 and the Hatch-Waxman extension under § 156. Rather, the two statutes are applied together where the Hatch-Waxman extension is calculated from the expiration date resulting from the terminal disclaimer, not from the date the patent would have expired without the terminal disclaimer.