On March 13, 2025, the U.S. Court of Appeals for the Federal Circuit affirmed a five-year patent term extension (“PTE”) for Merck’s sugammadex patent, holding that the district court had correctly calculated PTE based on the issue date of the original patent rather than the issue date of the reissued patent.[1]
Background
The case originated as a series of Hatch-Waxman litigations related to Merck’s Bridion®, a drug with the active ingredient sugammadex which is administered as an intravenous injection to reverse neuromuscular blockade, a form of paralysis induced by rocuronium bromide and vecuronium bromide in certain types of surgery.[2]
Merck originally obtained U.S. Patent No. 6,670,340 (“the ’340 patent”), which is directed to a class of 6-mercapto-cyclodextrin derivatives and issued on December 30, 2003, and applied to the Food and Drug Administration (“FDA”) for approval of a species within that class, sugammadex, shortly after on April 13, 2004.[3] Years later, while regulatory review was ongoing, Merck filed a reissue application for the ’340 patent that included both the original claims and narrower claims specifically directed to sugammadex, which was granted and issued as U.S. Patent No. RE44,733 (“the RE’733 patent”) on January 28, 2014.[4] The FDA approved sugammadex on December 15, 2015.
On February 10, 2016, Merck filed a PTE application for the RE’733 patent seeking PTE under 35 U.S.C. § 156 based on the original ’340 patent’s issue date (capped at five years under § 156(g)(6)(A)).[5] On February 4, 2020, the U.S. Patent and Trademark Office (“PTO”) granted a five-year PTE based on the ’340 patent’s issue date, extending the RE’733 patent’s expiration date from January 27, 2021, to January 27, 2026.[6]
In early 2020, Merck filed Hatch-Waxman lawsuits in the U.S. District Court for the District of New Jersey against several companies (collectively, “Aurobindo”) that had filed Abbreviated New Drug Applications (“ANDAs”) for generic versions of Bridion® and which had submitted Paragraph IV certifications as to the RE’733 patent.[7] The cases were consolidated.
At trial, Aurobindo argued that based on the plain text of § 156(c), which provides that the length of patent term extension is “the time equal to the regulatory review period… occur[ring] after the date the patent is issued,” the PTO should have calculated the RE’733 patent’s PTE based on the reissued patent’s issue date, rather than the original patent’s issue date.[8] Thus, the RE’733 patent was entitled not to a five-year PTE, but only to a 686-day PTE based on the period of regulatory review that had taken place after the RE’733 patent’s January 28, 2014 issue date, corresponding to an expiration date of December 14, 2022.[9] Thus, Aurobindo sought to reduce the granted PTE by 1,140 days.
The district court rejected Aurobindo’s construction, and concluded that, when calculating PTE for a reissued patent, the PTO is statutorily required to base its calculation on the original patent’s issue date rather than the reissue patent’s issue date.[10] It thus held that the RE’733 patent was entitled to its full five-year PTE.[11]
Aurobindo appealed the decision. Notably, the PTO filed an amicus brief in support of Merck and took part in the oral argument on February 4, 2025.
The Federal Circuit’s Affirmance
On appeal, the Federal Circuit affirmed the district court’s holding, explaining that
[I]n the context of reissued patents, the reference to “the patent” in subsection 156(c) is to the original patent. Here, the ’340 patent included claims directed to the active ingredient for a drug product . . . . Under these circumstances, the RE’733 patent was entitled to a five-year PTE based on the ’340 patent’s issue date, since regulatory review effectively prevented the patent owner from enforcing the patent during that period.[12]
Central to the Federal Circuit’s decision was the statutory interpretation of 35 U.S.C. § 156(c). In this respect, the Federal Circuit found that “the language of subsection 156(c) standing alone is ambiguous.”[13] Looking to the statutory text and the broader context of the statute, the Federal Circuit explained that Congressional intent made clear the purpose of this section of the Hatch-Waxman Act: “to compensate the pharmaceutical companies for the effective truncation of their patent terms while waiting for regulatory approval of new drug applications.”[14] It emphasized that “[t]he statute contemplates a patentee receiving time lost in its patent term by reason of FDA delay, and the statute should be liberally interpreted to achieve this end,” and observed that Aurobindo’s construction of the statute, which would “den[y] Merck compensation for all but a small period of the delay,” was at odds with the purpose of the statute.[15]
The Federal Circuit thus concluded that “[a] reissued patent is entitled to PTE based on the original patent’s issue date where, as here, the original patent included the same claims directed to a drug product subject to FDA review.”[16] It added as a final note that the PTO’s revised Manual of Patent Examining Procedure, which instructs patent examiners to calculate the amount of PTE to which reissued patents are entitled based on the original patent’s issue date so long as both patents claimed or claim the approved product, “substantially tracks with our analysis as applied in this case.”[17]
Implications for PTE Based on Regulatory Review Period
In light of the Federal Circuit’s holding, the status quo with respect to how the USPTO calculates PTE based on the FDA’s regulatory review period remains unchanged. As the PTO suggested during oral argument, calculating PTE based on reissue date rather than the original patent’s issue date could lead to gamesmanship to maximize PTE by “either not filing the reissue or, at the [PTO], taking certain steps to delay your reissue application, until you get PTE on the original patent.” However, the affirmance avoids the need for such measures—patent owners can continue to file reissue patents without opening themselves up to the possibility of cutting off PTE (provided that both the reissued and original patents include the same claims directed to the approved drug product).
[1] Merck Sharp & Dohme B.V. v. Aurobindo Pharma USA, Inc., No. 23-2254 (Fed. Cir. Mar. 13, 2025) (available at https://www.cafc.uscourts.gov/opinions-orders/23-2254.OPINION.3-13-2025_2481365.pdf).
[2] Id. at 5-6.
[3] Id. at 5.
[4] Id. at 6.
[5] Id. at 6-7; 35 U.S.C. §§ 156(c), 156(g).
[6] Merck at 7.
[7] Id. at 7-8.
[8] Id. at 8.
[9] Id.
[10] Id. at 8-9.
[11] Id. at 9.
[12] Id. at 4.
[13] Id. at 10.
[14] Id. at 10-12.
[15] Id. at 13.
[16] Id. at 14-15.
[17] Id. at 16-17.
