Astellas v. Creekwood: Mirabegron Patent Dispute Ends in Settlement
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📋 Case Summary
| Case Name | Astellas Pharma, Inc. v. Creekwood Pharmaceuticals LLC |
| Case Number | 1:25-cv-00045 (D. Del.) |
| Court | U.S. District Court for the District of Delaware |
| Duration | Jan 2025 – Jan 2026 363 days |
| Outcome | Settlement & License Agreement |
| Patents at Issue | |
| Accused Products | Mirabegron Extended-Release Oral Tablets (25 mg & 50 mg) |
Case Overview
A closely watched pharmaceutical patent infringement case concluded on January 8, 2026, when Astellas Pharma, Inc. and Creekwood Pharmaceuticals LLC filed a joint stipulation of dismissal in the U.S. District Court for the District of Delaware, formally resolving Civil Action No. 1:25-cv-00045. The dispute centered on four patents protecting mirabegron extended-release oral tablets — the active ingredient in Myrbetriq® — and was resolved through a confidential Settlement and License Agreement just 363 days after filing.
The case reflects a well-established pattern in Hatch-Waxman pharmaceutical patent litigation: brand manufacturers asserting overlapping patent estates against generic challengers, with settlement emerging as the commercially rational endpoint. For patent attorneys, IP counsel, and R&D professionals operating in the branded pharmaceutical space, this resolution offers instructive signals about portfolio construction, ANDA litigation strategy, and the regulatory obligations that accompany pharma patent settlements. The mandatory FTC and DOJ submission requirement under the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (MMA) adds a layer of public accountability rarely seen in other IP settlements.
The Parties
⚖️ Plaintiff
A Japanese multinational pharmaceutical company with a significant U.S. presence, holding branded rights to Myrbetriq® (mirabegron).
🛡️ Defendant
ANDA applicant seeking regulatory approval to market a generic version of mirabegron extended-release oral tablets.
The Patents at Issue
Four U.S. patents formed the core of Astellas’s infringement allegations, protecting mirabegron extended-release oral tablets — the active ingredient in Myrbetriq®:
- • U.S. Patent No. 10,842,780 (App. No. 15/432,854) — formulation and/or method-of-treatment claims
- • U.S. Patent No. 11,707,451 (App. No. 17/114,890) — continuation claims building on the ‘780 patent family
- • U.S. Patent No. 12,059,409 (App. No. 18/613,270) — later-generation patent in the mirabegron portfolio
- • U.S. Patent No. 12,097,189 (App. No. 18/613,281) — a closely related continuation addressing formulation or dosing parameters
The ‘409 and ‘189 patents, bearing 2024–2025 issue dates inferred from their high patent numbers, represent Astellas’s most recent prosecution activity — a hallmark of evergreening strategy designed to extend commercial exclusivity beyond earlier patent expirations.
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The Verdict & Legal Analysis
Outcome
The case terminated through a joint stipulation of dismissal without prejudice, entered by the court on January 8, 2026. All claims related to U.S. Patent Nos. 10,842,780, 11,707,451, 12,059,409, and 12,097,189 were dismissed. The underlying resolution is a Settlement and License Agreement — the specific financial terms, royalty structures, and authorized generic entry dates were not disclosed publicly. Each party agreed to bear its own costs and attorneys’ fees, indicating neither side extracted a clear litigation victory on procedural grounds.
Regulatory Compliance Obligations
A legally significant procedural element of this settlement is the mandatory submission of the Settlement and License Agreement to the FTC Bureau of Competition and the DOJ Antitrust Division pursuant to the Medicare Prescription Drug, Improvement, and Modernization Act of 2003. This requirement applies to any final settlement between an NDA holder and an ANDA filer involving patent claims and potential delayed generic entry. The agencies review such agreements for “reverse payment” or “pay-for-delay” arrangements that may violate antitrust laws under FTC v. Actavis, Inc., 570 U.S. 136 (2013). The court also retained jurisdiction to reopen the matter in the event the agencies render the agreement void — an unusual but standard protective provision in MMA-compliant settlements.
Evergreening Patent Strategy — Analysis
The presence of two late-series patents (‘409 and ‘189, App. Nos. 18/613,270 and 18/613,281) alongside the earlier ‘780 and ‘451 patents illustrates a multi-layered patent portfolio strategy. By continuing to prosecute continuation applications as the lead compound patents aged, Astellas extended its defensive perimeter. For ANDA challengers, this architecture demands comprehensive Paragraph IV certification analysis across multiple patent generations and application families — increasing the cost and complexity of generic entry litigation.
Freedom to Operate (FTO) Analysis
This settlement highlights critical IP risks in pharmaceutical development. Choose your next step:
📋 Understand This Case’s Impact
Learn about the specific risks and implications from this litigation.
- Analyze prosecution history for continuation applications
- Identify key claim construction patterns in pharma patents
- Evaluate competitive IP landscaping in the mirabegron market
🔍 Check My Product’s Risk
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- Input your drug formulation or technical features
- AI identifies potentially blocking patents (including continuations)
- Get actionable risk assessment report for ANDA filings
High Risk Area
Mirabegron ER formulation & dosing patents
4 Patents Asserted
Across multiple continuation families
Early Settlement
Opportunity for efficient resolution
✅ Key Takeaways
Astellas asserted four patents across multiple continuation families — a litigation strategy that compounds the defense burden on ANDA filers.
Explore multi-patent litigation strategies →Delaware District Court remains the premier Hatch-Waxman venue; venue selection is itself a strategic asset for pharmaceutical IP cases.
Analyze court trends & outcomes →MMA § 1112 submission obligations are non-negotiable in brand-generic settlements; *Actavis* antitrust risk must be integrated into settlement term negotiations.
Research antitrust implications →Without-prejudice dismissal preserves reopening rights if the FTC/DOJ voids the agreement, a standard protective mechanism in MMA-compliant settlements.
Review MMA settlement guidelines →Frequently Asked Questions
The case involved four U.S. patents: Nos. 10,842,780; 11,707,451; 12,059,409; and 12,097,189, all relating to mirabegron extended-release oral tablets (25 mg and 50 mg).
Federal law under the Medicare Modernization Act of 2003 requires all Hatch-Waxman patent settlements between NDA and ANDA parties to be filed with antitrust regulators to screen for anticompetitive “pay-for-delay” arrangements.
It means the claims could theoretically be refiled if the FTC or DOJ invalidates the Settlement and License Agreement — a standard protective mechanism in MMA-compliant pharmaceutical patent settlements.
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References
- PACER Case 1:25-cv-00045
- USPTO Patent Center
- FTC Hatch-Waxman Agreements
- Cornell Legal Information Institute — 21 U.S.C. § 355(j)(5)(B)(iii)
- FTC v. Actavis, Inc., 570 U.S. 136 (2013)
This article is for informational purposes only and does not constitute legal advice. All case information is drawn from publicly available court records. For platform capabilities, visit PatSnap.