Astellas v. Lupin & Zydus: Mirabegron ER Tablet Appeal Voluntarily Dismissed
Astellas Pharma and its affiliates voluntarily dismissed their Federal Circuit appeal against generic manufacturers Lupin and Zydus over US11707451B2, covering mirabegron extended-release tablets. The case closed just 35 days after filing, with each side bearing its own costs under Fed. R. App. P. 42(b).
A 35-day Federal Circuit exit in a high-stakes generics fight
Astellas Pharma, Inc., Astellas Pharma Global Development, Inc., and Astellas Ireland Co., Ltd. filed this Federal Circuit appeal on 1 May 2024, asserting infringement of US11707451B2 against generic manufacturers Lupin Limited, Lupin Pharmaceuticals, Inc., Zydus Lifesciences Ltd., and Zydus Pharmaceuticals (USA), Inc. The patent covers mirabegron extended-release tablet formulations at 25 mg and 50 mg doses — the branded Myrbetriq product used to treat overactive bladder, a multi-billion-dollar therapeutic category.
The appeal was voluntarily dismissed on 5 June 2024 under Federal Rule of Appellate Procedure 42(b), just 35 days after filing. The dismissal order specifies that each side shall bear its own costs. The public record does not specify whether the dismissal was with or without prejudice, which carries materially different implications for Astellas’s ability to re-litigate the same claims against these defendants in the future.
A 35-day lifespan for a Federal Circuit appeal is consistent with parties reaching a commercial resolution — such as a licensing agreement or negotiated generic entry date — shortly after the appeal was filed or even before. The speed and the mutual cost-bearing arrangement suggest a negotiated exit rather than unilateral abandonment, though the public record does not confirm any settlement terms. Whether Astellas retains the right to reassert US11707451B2 against Lupin or Zydus remains an open question.
Filing to Voluntary dismissal in 35 days
35 days — unusually swift close, suggesting pre-existing settlement or commercial resolution
Voluntarily dismissed: what the Fed. R. App. P. 42(b) exit means for both sides
Fed. R. App. P. 42(b): voluntary dismissal at the appellant’s election
Rule 42(b) allows an appellant to dismiss its own appeal by filing a signed agreement or stipulation. It requires no merits ruling from the court. Here, the order records that ‘the parties having so agreed’ — indicating mutual consent rather than a unilateral withdrawal. No substantive legal findings were made on the validity or infringement of US11707451B2.
No merits adjudicationThe public record is silent on prejudice — the distinction matters
A dismissal with prejudice bars Astellas from re-filing the same claims against these defendants; without prejudice preserves that right. The court order simply records dismissal under Rule 42(b) with mutual cost-bearing. Because the order does not expressly state either, practitioners cannot assume either outcome. Any licensing or consent agreement reached privately would govern whether future assertion is contractually restricted.
Prejudice status unknownLupin and Zydus exit without an adverse merits ruling on their ANDAs
Lupin and Zydus avoid a Federal Circuit ruling that could have affirmed patent validity and extended Myrbetriq’s exclusivity period. However, without a finding of non-infringement or invalidity, they cannot rely on this case as legal precedent for their ANDA positions. Any commercial agreement reached remains confidential and may impose its own constraints on generic market entry timing.
No precedent for genericsMirabegron exclusivity timeline likely resolved outside the courtroom
The mutual consent and 35-day duration strongly suggest a negotiated resolution governing generic entry dates for mirabegron ER tablets. For competitors beyond Lupin and Zydus, US11707451B2 remains an active enforcement asset with no adverse appellate ruling. Branded mirabegron formulation patents in the overactive bladder space continue to carry enforcement credibility against future ANDA filers.
Patent remains intactFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Astellas Pharma, Inc. | Company | Pharmaceutical innovator — holder of US11707451B2 covering mirabegron ER tabletsSearch in Eureka ↗ |
| Co-Plaintiff | Astellas Pharma Global Development, Inc. | Company | Search in Eureka ↗ |
| Co-Plaintiff | Astellas Ireland Co., Ltd. | Company | Search in Eureka ↗ |
| Defendant | Lupin Limited | Individual | Generic manufacturers Lupin Limited, Lupin Pharmaceuticals, Zydus Lifesciences, and Zydus Pharmaceuticals (USA)Search in Eureka ↗ |
| Co-Defendant | Zydus Lifesciences Ltd. | Company | Search in Eureka ↗ |
| Co-Defendant | Lupin Pharmaceuticals, Inc. | Company | Search in Eureka ↗ |
| Co-Defendant | Zydus Pharmaceuticals (USA), Inc. | Company | Search in Eureka ↗ |
| Plaintiff counsel | Daniel M. Silver | Attorney | Counsel for Astellas Pharma, Inc.Search in Eureka ↗ |
| Plaintiff law firm | McCarter & English LLP | Law Firm | Representing Astellas Pharma, Inc.Search in Eureka ↗ |
| Defendant counsel | Andrea L. Cheek | Attorney | Counsel for Lupin LimitedSearch in Eureka ↗ |
| Defendant counsel | Carol Pitzel Cruz | Attorney | Counsel for Lupin LimitedSearch in Eureka ↗ |
| Defendant counsel | William R. Zimmerman | Attorney | Counsel for Lupin LimitedSearch in Eureka ↗ |
| Defendant law firm | Knobbe Martens Olson & Bear, LLP | Law Firm | Representing Lupin LimitedSearch in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | Court of Appeals for the Federal CircuitSearch in Eureka ↗ |
Official order — verbatim text
The order’s phrasing — ‘the parties having so agreed’ — confirms this was a consensual dismissal under Fed. R. App. P. 42(b), not a unilateral withdrawal. No legal standard was applied to the merits; the Federal Circuit made no finding on claim construction, validity, or infringement of US11707451B2. The absence of a prejudice designation in the public order means the downstream re-litigation rights of both parties depend on any private agreement reached between them, the terms of which are not visible in the court record.
US11707451B2 — mirabegron extended-release tablet formulations
US11707451B2 (application number US17/114890) covers mirabegron extended-release tablet formulations at 25 mg and 50 mg strengths. Mirabegron is a beta-3 adrenergic receptor agonist used in the treatment of overactive bladder — a therapeutic category with substantial global commercial value. The extended-release formulation claim set is directed at the specific pharmaceutical composition and release characteristics that underpin the branded Myrbetriq product, providing protection beyond the active compound itself.
Formulation patents of this type are strategically significant in pharmaceutical IP portfolios because they extend enforceable exclusivity past the expiry of core compound patents. In the ANDA context, they require generic challengers to file Paragraph IV certifications and expose themselves to 30-month stays. Because this appeal concluded without a validity or infringement ruling, the patent’s enforceability against third-party generic filers remains fully intact, making it a continuing barrier to generic market entry for mirabegron ER tablets.
Should you run an FTO against US11707451B2?
Any company developing or commercialising mirabegron extended-release tablet formulations — whether through an ANDA, 505(b)(2), or branded pathway — should conduct a freedom-to-operate analysis against US11707451B2 before filing or advancing product development. The patent survived this Federal Circuit proceeding without an adverse ruling, and Astellas has demonstrated willingness to enforce it at the appellate level. The 25 mg and 50 mg dose strengths are specifically named in the product scope, making direct substitution without FTO analysis a significant commercial risk.
PatSnap Eureka’s FTO Search Agent allows R&D and IP teams to map claim elements of US11707451B2 against proposed formulation designs, identify relevant prior art, and flag related continuation or divisional applications in the Astellas portfolio. Given the multi-defendant enforcement pattern visible in this case — four generic entities named simultaneously — early FTO work is particularly important for companies at the ANDA preparation stage.
Run a freedom-to-operate analysis on US11707451B2 to assess your product’s exposure
Run FTO in Eureka →Similar Federal Circuit ANDA appeals: mirabegron and ER tablet patent disputes
Explore Federal Circuit appeals involving extended-release pharmaceutical formulation patents and ANDA infringement actions with comparable voluntary dismissal or settlement outcomes.
What this case signals for the pharmaceutical generics IP landscape
Rapid voluntary dismissals at the Federal Circuit in ANDA disputes often signal negotiated entry dates or licensing — not legal weakness.
Speed of dismissal is the signal: 35 days points to a pre-negotiated exit
Federal Circuit appeals rarely resolve in 35 days through litigation. The mutual-consent language in the order and the symmetric cost-bearing arrangement are consistent with a commercial deal reached either during or immediately after the district court proceedings. IP teams monitoring branded-generic disputes should treat rapid Rule 42(b) dismissals as indicators of confidential licensing or consent-judgment agreements.
US11707451B2 carries undiminished enforcement value against future ANDA filers
Because no merits ruling was issued, US11707451B2 has neither been invalidated nor found not infringed. Astellas retains full enforcement rights against any subsequent ANDA filer for mirabegron ER 25 mg and 50 mg tablets. Generics companies at earlier stages of ANDA prosecution should treat this patent as a live blocking asset and conduct thorough FTO analysis before proceeding.
Astellas v Lupin — key questions answered
The voluntary dismissal under Fed. R. App. P. 42(b) made no merits ruling on US11707451B2. The patent was neither invalidated nor found not infringed. Astellas retains full enforcement rights against future ANDA filers. The dismissal’s prejudice status — which would determine re-assertion rights against Lupin and Zydus specifically — is not stated in the public court order.
The court order does not specify. It records only that the proceeding is dismissed under Fed. R. App. P. 42(b) and that each side bears its own costs. The public record is silent on prejudice. Any determination of re-assertion rights against Lupin, Lupin Pharmaceuticals, Zydus Lifesciences, or Zydus Pharmaceuticals would depend on any private agreement between the parties, which has not been made public.
US11707451B2 (application US17/114890) is a patent held by Astellas covering mirabegron extended-release tablet formulations at 25 mg and 50 mg strengths. Mirabegron is a beta-3 adrenergic receptor agonist marketed as Myrbetriq for overactive bladder. The patent protects specific formulation and release characteristics, providing exclusivity beyond the active compound and forming a key ANDA litigation asset in the Orange Book listing for Myrbetriq.
A 35-day lifespan is atypically short for a Federal Circuit appeal and is consistent with parties having reached a commercial resolution — such as a licence agreement or negotiated generic entry date — either before filing or shortly after. The mutual-consent language in the dismissal order supports a negotiated exit rather than a unilateral withdrawal. No appellate briefing schedule appears to have been completed in the public docket.
The defendants were Lupin Limited, Lupin Pharmaceuticals, Inc., Zydus Lifesciences Ltd., and Zydus Pharmaceuticals (USA), Inc. — all generic manufacturers with ANDA activity in the mirabegron extended-release tablet market. The multi-defendant structure is typical of coordinated ANDA Paragraph IV litigation where multiple filers challenge the same Orange Book-listed patents simultaneously.
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