Aurobindo v. Merck Sharp & Dohme: Federal Circuit Affirms Sugammadex PTE
Aurobindo Pharma challenged the five-year patent term extension granted to Merck Sharp & Dohme’s reissued patent USRE044733E covering sugammadex, the active ingredient in BRIDION®. The Federal Circuit affirmed the district court, holding that the PTE clock runs from the original patent’s issue date — a ruling with significant implications for reissued pharmaceutical patents sector-wide.
Federal Circuit resolves reissued patent PTE eligibility for sugammadex
Filed on 9 August 2023, Case No. 23-2254 saw Aurobindo Pharma, Ltd. appeal to the U.S. Court of Appeals for the Federal Circuit against Merck Sharp & Dohme, B.V., contesting the validity of a five-year patent term extension granted for USRE044733E — the reissued patent protecting sugammadex, the cyclodextrin-based neuromuscular reversal agent marketed as BRIDION®. The core legal question was whether, under 35 U.S.C. § 156(c), ‘the patent’ in the context of a reissued patent refers to the reissue patent itself or the original patent from which it derives.
The Federal Circuit affirmed the district court on 13 March 2025, concluding that for purposes of § 156(c) PTE eligibility, ‘the patent’ refers to the original patent — here, the ‘340 patent — which included claims directed to sugammadex and was issued before FDA approval of BRIDION®. This interpretation validated the full five-year extension, preserving Merck’s market exclusivity window and leaving Aurobindo’s generic entry strategy materially constrained by the extended term.
The 582-day duration suggests a carefully litigated statutory-interpretation question rather than a fact-heavy record dispute, consistent with the Federal Circuit’s treatment of pure questions of law on appeal. What drove the timeline likely includes the novelty of the reissued-patent PTE question under § 156(c) and the commercial stakes of BRIDION® exclusivity. The public record does not disclose whether settlement was explored or whether Aurobindo intends to seek en banc rehearing or certiorari.
Filing to Appeal Dismissed in 582 days
582 days — above the median for Federal Circuit pharmaceutical patent appeals
Federal Circuit affirms: what the PTE ruling means for both parties
Affirmance means the lower decision stands without reversible error
At the appellate level, ‘AFFIRMED’ signals that the Federal Circuit reviewed the district court’s statutory interpretation of 35 U.S.C. § 156(c) and found no reversible legal error. The court accepted that ‘the patent’ in the PTE subsection refers to the original pre-reissue patent when assessing term extension eligibility — a question of statutory construction reviewed de novo. The district court’s grant of the five-year PTE therefore survives intact.
Statutory interpretation affirmedMerck’s PTE survives: BRIDION® exclusivity period protected
For Merck Sharp & Dohme, affirmance locks in the five-year patent term extension for USRE044733E, anchored to the original ‘340 patent’s issue date. This preserves the extended exclusivity window over sugammadex and delays generic competition from Aurobindo and potentially other ANDA filers. The ruling reinforces that reissued pharmaceutical patents can inherit PTE eligibility from their original patent predecessors — a significant commercial win.
Exclusivity window preservedAurobindo’s generic path remains blocked at this appellate stage
Aurobindo’s appellate challenge has failed at the Federal Circuit, the highest court for patent law short of the Supreme Court. The ruling raises the bar for any further challenge: Aurobindo would need to seek en banc rehearing or petition for certiorari — both high-threshold remedies — or pursue alternative invalidity or non-infringement strategies. For the near term, generic sugammadex entry appears constrained by the extended patent term.
Appellate options exhausted at this levelReissued patents can now anchor PTE claims — a sector-wide signal
This ruling strengthens the PTE framework for branded pharmaceutical companies holding reissued patents: originators can now point to Federal Circuit authority confirming that a reissue patent’s PTE eligibility looks back to the original patent’s issue date. For generic manufacturers, the decision raises the complexity and risk of PTE challenges against reissued patents. R&D teams working with cyclodextrin-based drug delivery or neuromuscular agents should factor this extended exclusivity into competitive landscape assessments.
PTE framework for reissues strengthenedFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Aurobindo Pharma, Ltd. | Company | Indian generic pharmaceutical manufacturer — challenger of PTE for USRE044733ESearch in Eureka ↗ |
| Defendant | Merck Sharp & Dohme, B.V. | Individual | Merck subsidiary and holder of reissued patent USRE044733E covering sugammadex (BRIDION®)Search in Eureka ↗ |
| Plaintiff counsel | George Barry III | Attorney | Counsel for Aurobindo Pharma, Ltd.Search in Eureka ↗ |
| Plaintiff counsel | Michael Patrick Hogan | Attorney | Counsel for Aurobindo Pharma, Ltd.Search in Eureka ↗ |
| Plaintiff counsel | R. Touhey Myer | Attorney | Counsel for Aurobindo Pharma, Ltd.Search in Eureka ↗ |
| Plaintiff counsel | Timothy H. Kratz | Attorney | Counsel for Aurobindo Pharma, Ltd.Search in Eureka ↗ |
| Plaintiff law firm | Kratz & Barry LLP | Law Firm | Representing Aurobindo Pharma, Ltd.Search in Eureka ↗ |
| Defendant counsel | Alan Ernst Littmann | Attorney | Counsel for Merck Sharp & Dohme, B.V.Search in Eureka ↗ |
| Defendant counsel | Andrea Weiss Jeffries | Attorney | Counsel for Merck Sharp & Dohme, B.V.Search in Eureka ↗ |
| Defendant counsel | Anthony Insogna Esq. | Attorney | Counsel for Merck Sharp & Dohme, B.V.Search in Eureka ↗ |
| Defendant counsel | Ashwin Shandilya | Attorney | Counsel for Merck Sharp & Dohme, B.V.Search in Eureka ↗ |
| Defendant counsel | David M. Krinsky | Attorney | Counsel for Merck Sharp & Dohme, B.V.Search in Eureka ↗ |
| Defendant counsel | Doug J. Winnard | Attorney | Counsel for Merck Sharp & Dohme, B.V.Search in Eureka ↗ |
| Defendant counsel | Sarah Geers | Attorney | Counsel for Merck Sharp & Dohme, B.V.Search in Eureka ↗ |
| Defendant counsel | Shaun Patrick Mahaffy | Attorney | Counsel for Merck Sharp & Dohme, B.V.Search in Eureka ↗ |
| Defendant counsel | Shayna S. Cook | Attorney | Counsel for Merck Sharp & Dohme, B.V.Search in Eureka ↗ |
| Defendant counsel | Stanley E. Fisher | Attorney | Counsel for Merck Sharp & Dohme, B.V.Search in Eureka ↗ |
| Defendant law firm | Goldman Ismail Tomaselli Brennan & Baum LLP | Law Firm | Representing Merck Sharp & Dohme, B.V.Search in Eureka ↗ |
| Defendant law firm | Jones Day | Law Firm | Representing Merck Sharp & Dohme, B.V.Search in Eureka ↗ |
| Defendant law firm | Williams & Connolly LLP | Law Firm | Representing Merck Sharp & Dohme, B.V.Search in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | Court of Appeals for the Federal CircuitSearch in Eureka ↗ |
Official order — verbatim text
The Federal Circuit’s affirmance rests on a de novo statutory construction of 35 U.S.C. § 156(c), confirming that ‘the patent’ in the PTE subsection refers to the original patent in a reissue chain — not the reissue patent itself. By anchoring the five-year PTE to the ‘340 patent’s issue date (which predated FDA approval of BRIDION®), the court validated the full extension. The unambiguous ‘AFFIRMED’ disposition leaves no remand, no partial reversal, and no further fact-finding — the district court’s ruling is final at this appellate level.
USRE044733E — Sugammadex neuromuscular block reversal agent
USRE044733E is a reissued U.S. patent protecting 6-mercapto-cyclodextrin derivatives — specifically sugammadex — as reversal agents for drug-induced neuromuscular blockade. The reissue patent derives from an original patent (the ‘340 patent) that predated FDA approval of BRIDION®, the commercial sugammadex product. This chronological relationship between the original patent’s issue date and FDA approval was central to the court’s PTE eligibility analysis under 35 U.S.C. § 156, making this patent’s prosecution history and reissue chain critically important to understanding the extended exclusivity period.
Sugammadex occupies a defensible niche in anaesthesia pharmacology: it is the only selective relaxant binding agent (SRBA) approved for reversal of rocuronium- and vecuronium-induced neuromuscular block. With BRIDION® generating significant global revenues, the PTE attached to USRE044733E carries substantial commercial weight. The Federal Circuit’s ruling strengthens the enforceability of this extended term, signalling to the broader pharmaceutical sector that reissued patents covering FDA-approved drugs are capable of attracting full § 156(c) PTE protection — raising the competitive moat for originators in this class.
Should you run an FTO against USRE044733E?
Any company developing cyclodextrin-based drug delivery systems, neuromuscular reversal agents, or modified cyclodextrin scaffolds should treat USRE044733E as a live FTO risk. The Federal Circuit’s affirmance confirms the patent carries a court-validated extended term. R&D teams working on next-generation neuromuscular blocking agent reversal, or on cyclodextrin-encapsulated API formulations, should assess whether their compounds or methods fall within the claims of the reissued patent — particularly given the reissue’s potential for broadened claim scope relative to the original.
PatSnap Eureka’s FTO Search Agent enables rapid, AI-powered clearance searches across the USRE044733E patent family, its original application chain (US13/432742), and related cyclodextrin chemistry filings. Eureka can map claim scope against your specific compound or formulation, flag continuation and divisional risk, and surface prior art relevant to any invalidity argument — all in a fraction of the time of a traditional FTO engagement. This is especially valuable where, as here, the enforceability of the extended term has been confirmed at the Federal Circuit level.
Run a freedom-to-operate analysis on USRE044733E to assess your product’s exposure
Run FTO in Eureka →Similar Federal Circuit pharmaceutical patent term extension cases
Federal Circuit appeals involving pharmaceutical PTE eligibility and reissued patents, with comparable § 156(c) statutory construction disputes and generic entry timing stakes.
What this case signals for the pharmaceutical patent IP landscape
The Federal Circuit’s § 156(c) ruling reshapes how originators and generics assess PTE eligibility for reissued patents.
Originators holding reissued patents should audit PTE eligibility immediately
This ruling confirms that the PTE clock for reissued patents can anchor to the original patent’s issue date. Branded pharmaceutical companies with reissued patents covering FDA-approved drugs should proactively audit their PTE positions under § 156(c) — the Federal Circuit has now provided a clear interpretive framework that could extend exclusivity windows previously considered uncertain.
Generic filers must re-examine ANDA timelines where reissued patents carry PTE
Any generic manufacturer with an ANDA targeting a drug protected by a reissued patent with a PTE should reassess its market entry timeline. The ruling suggests PTEs on reissued patents are entitled to deference from the original patent’s issue date, potentially extending the exclusivity period beyond what challengers had modelled. Updated freedom-to-operate analyses are warranted.
Aurobindo v Merck — key questions answered
The Federal Circuit affirmed the district court’s ruling that the reissued patent USRE044733E was entitled to a five-year patent term extension under 35 U.S.C. § 156(c), based on the issue date of the original ‘340 patent rather than the reissue patent itself. The court held that ‘the patent’ in § 156(c) refers to the original patent that included claims directed to the drug product (sugammadex) and was issued before FDA approval of BRIDION®.
USRE044733E is a reissued U.S. patent covering 6-mercapto-cyclodextrin derivatives used as reversal agents for drug-induced neuromuscular blockade. It protects sugammadex, the active ingredient in Merck’s BRIDION®, which is the only approved selective relaxant binding agent for reversing rocuronium- and vecuronium-induced neuromuscular block in anaesthesia settings.
The ruling confirms that reissued pharmaceutical patents can inherit PTE eligibility from their original patent’s issue date, potentially extending market exclusivity beyond periods that generic manufacturers may have anticipated. Generic filers with ANDAs targeting BRIDION® or other drugs protected by reissued patents with PTEs should reassess their projected market entry timelines and conduct updated freedom-to-operate analyses.
Following a Federal Circuit affirmance, the available options are limited to petitioning for en banc rehearing before the full Federal Circuit or filing a petition for certiorari to the U.S. Supreme Court. Both are high-threshold remedies with low grant rates. Aurobindo could also pursue alternative litigation strategies such as challenging specific claim validity via inter partes review at the USPTO, though the PTE interpretation itself is now settled Federal Circuit precedent.
Under 35 U.S.C. § 156(c), a patent is eligible for a PTE if it was issued before FDA regulatory approval of the drug it covers, among other requirements. The Federal Circuit held that for a reissued patent, this condition is assessed by reference to the original patent’s issue date — not the reissue patent’s issue date. Because the ‘340 original patent was issued before BRIDION® received FDA approval, USRE044733E satisfied the eligibility condition and was entitled to the full five-year extension.
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