Astellas Pharma, alongside the Regents of the University of California, has secured a major legal victory in Germany as the Federal Patent Court rejected a nullity suit challenging one of its key intellectual property rights protecting the blockbuster prostate cancer treatment Xtandi. The decision strengthens Astellas’ position as it continues to defend its IP portfolio for the drug across multiple jurisdictions.
The patent at the center of the dispute is European Patent EP 1 893 196, which protects the active pharmaceutical ingredient enzalutamide, the core compound in Xtandi. In Germany, the Supplementary Protection Certificate (SPC 12 2013 000 155.0) linked to EP 196 extends market exclusivity until June 25, 2028, beyond the patent’s official expiry in May 2026.
A Coordinated Challenge by Generics
The challenge was led by Hexal, a subsidiary of Sandoz, with Accord Healthcare, Synthon, and Stada joining the suit in a bid to invalidate the patent and gain earlier access to the market for generic enzalutamide formulations. However, in the recently concluded German case (3 Ni 20/23), the court sided with the patent holders.
Astellas, the exclusive sub-licensee of the patent rights for enzalutamide, participated in the proceedings as an intervenor, backing the University of California, which holds the original rights. The court found no grounds to invalidate the patent, thus preserving Astellas’ market exclusivity in Germany.
Wider Legal Landscape in the UK and Netherlands
The German case is part of a broader litigation strategy by generic manufacturers to challenge enzalutamide-related patents across Europe.
In October 2024, the UK High Court upheld both the British portion of EP 196 and the associated SPC in full. However, the ruling is currently under appeal.
In the Netherlands, the District Court of The Hague is expected to deliver its decision on EP 196 soon. Earlier this year, the same court upheld a related patent—EP 3 725 778, which protects enzalutamide’s formulation—marking another win for Astellas and its partners.
Legal Teams Behind the Battle
The high-profile nature of the case brought out some of Europe’s most experienced IP law firms specializing in life sciences:
Hexal was represented by patent specialists from df-mp Dörries Frank-Molnia & Pohlmann, a Munich-based firm with a strong track record in pharmaceutical patent disputes. Lead partner Elisabeth Greiner, supported by Holger Schimmel and Tom Schwarzer, led the challenge.
Accord Healthcare received support from patent attorneys Christian Hollatz and Veronika Müller at Ter Meer Steinmeister, and litigator Daniel Hoppe from the newly formed boutique Bonabry. Hoppe was joined by colleagues Konstantin Schallmoser and Sarah Salaschek, representing Synthon.
Stada’s case was handled by Alexander Wittkopp of Hamm & Wittkopp, another firm deeply entrenched in generic pharmaceutical patent litigation.
On the defence side, the Regents of the University of California and Astellas relied on the well-regarded Hoffmann Eitle team, led by Peter Klusmann and Dirk Schüßler-Langeheine, with assistance from Jan Zillies and Melanie Schain.
In UK proceedings, Kirkland & Ellis represented Astellas and the University, while the claimants were advised by Pinsent Masons.
In the Dutch litigation, Brinkhof is handling representation for the generics challengers, while Hoyng ROKH Monegier is acting for Astellas.
A Strategic Asset in Astellas’ Oncology Portfolio
Xtandi (enzalutamide) is a cornerstone of Astellas’ oncology franchise and one of the most commercially successful treatments for advanced prostate cancer, with global sales running into billions of dollars. Despite being indicated for a rare form of advanced cancer, the drug has seen significant market growth, especially in oral formulations that offer ease of use over competing treatments requiring injection.
The ongoing court battles underscore the value of enzalutamide’s exclusivity, and the resilience of Astellas’ legal defense so far suggests a robust IP strategy.
What Comes Next?
As litigation continues in the UK and Netherlands, and likely other markets, Astellas will aim to maintain its competitive edge through the strength of its patent portfolio. The latest German ruling will likely bolster its position in future proceedings, serving as a precedent that supports the validity and enforceability of EP 196 and its SPC.
For generic manufacturers, the fight isn’t over—but their path to market is now more complex, as courts increasingly affirm Astellas’ rights to protect a therapy that has reshaped treatment protocols for prostate cancer patients worldwide.
Astellas Pharma
Shares of Lupin and Zydus Life Slide After Losing US Patent Case to Astellas Pharma
Shares of Indian pharmaceutical giants Lupin and Zydus Lifesciences came under significant selling pressure on April 16, falling by 3% and 4.5% respectively. The decline followed a ruling by the U.S. District Court in Delaware in favor of Astellas Pharma, the original patent holder of Myrbetriq, a drug used to treat overactive bladder (OAB). The court determined that Lupin and Zydus had infringed upon Astellas’s patent rights, potentially paving the way for the withdrawal of their generic versions from the U.S. market.
Court Ruling Favors Astellas
The dispute centers around the ‘780 patent, which protects the formulation of Mirabegron, the active ingredient in Myrbetriq. Astellas Pharma filed a lawsuit claiming that the generic products manufactured by Lupin and Zydus violated this patent.
The judgment emphasized that the defendants failed to demonstrate that the patent was invalid on grounds such as lack of enablement, inadequate written description, or indefiniteness. With the court upholding the validity of the ‘780 patent, the generics produced by Lupin and Zydus are now under threat of being barred from sale in the U.S.
Financial Implications Loom
Market analysts have raised concerns over the financial impact this legal defeat could have on the Indian pharma companies. Myrbetriq was anticipated to contribute nearly $30 million in quarterly revenues to each company, according to some industry estimates. The ruling could not only impact future earnings but also result in penalties.
Vishal Manchanda, a pharmaceutical sector analyst at Systematix Group, told CNBC-TV18, “We expect a tangible hit to FY26 earnings for both Zydus Life and Lupin due to this development. Moreover, damages and potential penalties, if levied by the jury trial, could further strain their financials.”
The final determination of damages and any remaining disputes over infringement or validity will be taken up in a consolidated jury trial scheduled for 2026.
Companies Respond
In a post-market statement, Zydus Lifesciences acknowledged the verdict and said it is currently reviewing the court order and assessing its implications. “We are evaluating the potential impact of the said order on the operations of the Company and the legal remedies available with the Company,” the statement read.
Both Zydus and Lupin have filed a ‘Motion to Clarify’ in an effort to assert additional arguments regarding the patent’s validity, which the court will consider during the 2026 trial.
Background on Myrbetriq and the Patent Dispute
Myrbetriq, approved by the U.S. Food and Drug Administration in 2012, has been a high-value product in the OAB treatment category, with global sales reaching over a billion dollars annually in recent years. The drug works by relaxing the bladder muscle to increase storage capacity and reduce urinary urgency.
The ‘780 patent, central to the lawsuit, covers specific formulations and the method of administration of Mirabegron. Patent infringement in this context refers to manufacturing or selling a product that falls within the patent’s claim scope without authorization from the patent holder.
The ruling highlights the risks generic manufacturers face when attempting to enter markets dominated by patented medications. It also reaffirms the legal strength of patent protections in the U.S., particularly for high-value pharmaceutical products.
Market Reaction
Investors reacted swiftly to the news, with both Lupin and Zydus Life stocks falling sharply in trading. Analysts believe the market is pricing in not only the potential loss of revenue but also uncertainty around future legal proceedings and penalties.
The verdict serves as a cautionary tale for generics manufacturers and underscores the importance of thorough patent analysis before launching competing products in major markets like the United States.
As the legal battle progresses, the pharmaceutical sector will be closely watching the developments in the run-up to the 2026 trial, which will determine the extent of financial liability and the long-term market prospects for generic versions of Myrbetriq.
Court Ruling Favors Astellas
The dispute centers around the ‘780 patent, which protects the formulation of Mirabegron, the active ingredient in Myrbetriq. Astellas Pharma filed a lawsuit claiming that the generic products manufactured by Lupin and Zydus violated this patent.
The judgment emphasized that the defendants failed to demonstrate that the patent was invalid on grounds such as lack of enablement, inadequate written description, or indefiniteness. With the court upholding the validity of the ‘780 patent, the generics produced by Lupin and Zydus are now under threat of being barred from sale in the U.S.
Financial Implications Loom
Market analysts have raised concerns over the financial impact this legal defeat could have on the Indian pharma companies. Myrbetriq was anticipated to contribute nearly $30 million in quarterly revenues to each company, according to some industry estimates. The ruling could not only impact future earnings but also result in penalties.
Vishal Manchanda, a pharmaceutical sector analyst at Systematix Group, told CNBC-TV18, “We expect a tangible hit to FY26 earnings for both Zydus Life and Lupin due to this development. Moreover, damages and potential penalties, if levied by the jury trial, could further strain their financials.”
The final determination of damages and any remaining disputes over infringement or validity will be taken up in a consolidated jury trial scheduled for 2026.
Companies Respond
In a post-market statement, Zydus Lifesciences acknowledged the verdict and said it is currently reviewing the court order and assessing its implications. “We are evaluating the potential impact of the said order on the operations of the Company and the legal remedies available with the Company,” the statement read.
Both Zydus and Lupin have filed a ‘Motion to Clarify’ in an effort to assert additional arguments regarding the patent’s validity, which the court will consider during the 2026 trial.
Background on Myrbetriq and the Patent Dispute
Myrbetriq, approved by the U.S. Food and Drug Administration in 2012, has been a high-value product in the OAB treatment category, with global sales reaching over a billion dollars annually in recent years. The drug works by relaxing the bladder muscle to increase storage capacity and reduce urinary urgency.
The ‘780 patent, central to the lawsuit, covers specific formulations and the method of administration of Mirabegron. Patent infringement in this context refers to manufacturing or selling a product that falls within the patent’s claim scope without authorization from the patent holder.
The ruling highlights the risks generic manufacturers face when attempting to enter markets dominated by patented medications. It also reaffirms the legal strength of patent protections in the U.S., particularly for high-value pharmaceutical products.
Market Reaction
Investors reacted swiftly to the news, with both Lupin and Zydus Life stocks falling sharply in trading. Analysts believe the market is pricing in not only the potential loss of revenue but also uncertainty around future legal proceedings and penalties.
The verdict serves as a cautionary tale for generics manufacturers and underscores the importance of thorough patent analysis before launching competing products in major markets like the United States.
As the legal battle progresses, the pharmaceutical sector will be closely watching the developments in the run-up to the 2026 trial, which will determine the extent of financial liability and the long-term market prospects for generic versions of Myrbetriq.