Last week, the Federal Circuit issued a precedential decision in Merck Sharp & Dohme B.V. v. Aurobindo Pharma USA, Inc., No. 2023-2254 (Mar. 13, 2025), on appeal from the U.S. District Court for the District of New Jersey.
The case concerned the language of 35 U.S.C. § 156, which extends the term of drug patents by up to five years for any “regulatory review period . . . occur[ring] after the date the patent is issued.” Merck’s patent issued in 2003. It applied for FDA review of the involved drug in 2004 and eventually received approval in 2015. In the interim, Merck filed a reissue application preserving all the patent’s original claims while adding several narrower claims. The patent was reissued in 2014. Two years later, Merck requested a five-year patent term extension (“PTE”) from the USPTO calculated from the original patent’s issue date. That was granted, which extended the life of the patent from 2021 to 2026. Then in 2020, following ANDA filings by Aurobindo and the other defendants, Merck filed suit. Defendants argued the PTE under § 156 should have been calculated from the reissue date, which would have made the patent expire in 2022 because only a fraction of the regulatory review period occurred after reissuance. The district court disagreed, finding that reference to “the patent” in § 156 refers to the original patent and not the reissued patent. Defendants appealed.
The Federal Circuit found that the text of § 156 was ambiguous, so it looked at context and the statute’s purpose, which was clearly to compensate patent owners for lost patent term during the FDA review process. That purpose would be thwarted by effectively disabling PTE when a patent reissues. Moreover, the Court observed that a reissued patent still inherits the unexpired term of the original patent, thereby rendering irrelevant Defendants’ argument that because the original patent is dead upon reissue, any PTE must be calculated based on the reissue date.
According to the Federal Circuit, the only construction that comports with the purpose of the Hatch-Waxman Act is one that enables patent owners to recoup at least part of their period of patent protection lost during the pendency of regulatory review. Thus, the Court held that § 156 refers to the original patent and PTE must be calculated from its date of issuance—not the date of a subsequently reissued patent.
