Astellas Pharma Inc. et al. v. Zydus Pharmaceuticals (USA) Inc. et al.

This patent infringement case is a Hatch-Waxman action initiated by a group of global pharmaceutical companies against a generic drug manufacturer. The plaintiffs are Astellas Pharma Inc., a Japanese multinational pharmaceutical company, along with its U.S. affiliates and Medivation LLC, a biopharmaceutical company acquired by Pfizer in 2016. The plaintiffs develop and sell the blockbuster prostate cancer drug Xtandi® (enzalutamide). The defendants are Zydus Pharmaceuticals (USA) Inc., the U.S. generic division of its Indian parent company, Zydus Lifesciences Ltd. Zydus is a major manufacturer of generic drugs and is seeking regulatory approval to market its own version of Xtandi®. This type of litigation is common in the pharmaceutical industry, where brand-name drug manufacturers (innovators) sue generic manufacturers to enforce their patent rights and delay the entry of cheaper generic alternatives.

The dispute centers on Zydus's Abbreviated New Drug Application (ANDA) No. 217322, filed with the U.S. Food and Drug Administration (FDA) to market generic 40 mg and 80 mg tablets of enzalutamide. The plaintiffs allege that Zydus's proposed generic product will infringe U.S. Patent No. 12,161,628. The '628 patent, titled "Combination therapy," was issued in late 2024 and claims a method of treating prostate cancer in a patient by co-administering a specific daily dose of enzalutamide with rifampin, a strong CYP3A4 inducer. This lawsuit is part of a broader, multi-patent global strategy by Astellas to protect its multibillion-dollar Xtandi® franchise from generic competition.

The case is proceeding in the U.S. District Court for the District of New Jersey, where it has been assigned to District Judge Michael A. Shipp and Magistrate Judge Rukhsanah L. Singh. This venue is highly significant; the District of New Jersey is one of the top two districts in the U.S. for ANDA litigation, alongside the District of Delaware, due to the heavy concentration of pharmaceutical companies headquartered in the state. In recent years, New Jersey has seen a surge in patent case filings, particularly ANDA cases, making it a critical battleground for pharmaceutical patent disputes. The case, initially filed on October 11, 2024, has been consolidated with a related case against another generic filer (3:24-cv-09403), a common procedure to streamline pretrial proceedings for lawsuits involving the same patents and branded drug. The amended complaint adding the '628 patent was filed on January 3, 2025, signaling an ongoing and procedurally active litigation.

Key Legal Developments in Xtandi Patent Litigation

Case Analyst Summary:

This patent infringement action, part of the broader Hatch-Waxman litigation over Astellas's prostate cancer drug Xtandi® (enzalutamide), centers on Zydus's attempt to market a generic version of the drug. The case involving U.S. Patent No. 12,161,628 was initiated in late 2024 and swiftly consolidated into a broader action against multiple generic filers.

As of May 2026, the consolidated litigation remains in its early stages. Following initial pleadings and consolidation, the parties are likely engaged in fact and expert discovery. There have been no significant dispositive motions, claim construction hearings, or trial dates set. The case is proceeding under the management of Judge Michael A. Shipp and Magistrate Judge Rukhsanah L. Singh in the District of New Jersey. There is no public record of any parallel inter partes review (IPR) proceedings at the Patent Trial and Appeal Board (PTAB) filed by Zydus against the '628 patent.

Chronological Case History

2024-10-11: Initial Complaint Filed
Astellas and its partners filed a patent infringement lawsuit against Zydus Pharmaceuticals (USA) Inc. and Zydus Lifesciences Ltd. in the U.S. District Court for the District of New Jersey. The case was a response to Zydus filing an Abbreviated New Drug Application (ANDA) with the FDA seeking to market generic versions of Xtandi®. The initial complaint in case number 3:24-cv-09748 did not yet include the '628 patent.

2025-01-03: Amended Complaint Adds '628 Patent
Astellas filed an Amended Complaint for Patent Infringement, officially adding U.S. Patent No. 12,161,628, titled "Combination therapy," to the lawsuit. This patent was issued on December 10, 2024, and covers methods of treating prostate cancer by co-administering enzalutamide with another drug.

2025-01-16: Zydus Files Answer and Counterclaims
Zydus responded to the Amended Complaint by filing an answer and counterclaims. In this responsive pleading, Zydus likely denied infringement and asserted that the '628 patent is invalid, which is a standard defense in ANDA litigation.

2025-01-17: Cases Consolidated for All Purposes
Judge Michael A. Shipp ordered the consolidation of the Zydus case (3:24-cv-09748) with an earlier-filed case against another generic manufacturer, Astellas Pharma Inc. et al. v. Haimen Pharma Inc. et al. (3:24-cv-09403). The order stipulated that all future filings were to be made in the lead case, 3:24-cv-09403, and the docket for the Zydus-specific case was administratively terminated. Zydus is now listed as a "Consolidated Defendant" in the lead case.

2025-02-18: Scheduled Scheduling Conference
A scheduling conference was set to be held before Magistrate Judge Rukhsanah L. Singh. Following this conference, the court would have issued a scheduling order setting deadlines for discovery, claim construction briefing, and dispositive motions. The details of this order are not available in public search results but would govern the procedural timeline of the consolidated case.

Present Posture & Next Steps

The consolidated case, which now includes Zydus, is active and proceeding in the District of New Jersey. Based on a typical ANDA litigation timeline, the parties are expected to be in the discovery phase. The next major public milestones would likely be:

• Claim Construction (Markman) Hearing: Where the court will hear arguments and rule on the meaning of disputed patent claim terms.
• Expert Discovery: The exchange of expert reports on issues of infringement and validity.
• Summary Judgment Motions: Motions asking the court to decide the case, or parts of it, without a full trial.

No trial date has been set, and there is no indication from the available records that a settlement has been reached concerning the Xtandi patents at issue. It is important to distinguish this case from other litigation where Astellas and Zydus have recently settled, such as the dispute over the drug Myrbetriq® (mirabegron) in early 2026.

Parallel PTAB Proceedings

A thorough search of the USPTO's Patent Trial and Appeal Board (PTAB) database reveals no records of Zydus having filed an inter partes review (IPR) or post-grant review (PGR) petition challenging the validity of U.S. Patent No. 12,161,628. The absence of a PTAB challenge means the validity of the patent will, for now, be adjudicated solely within the district court litigation.

Counsel for Plaintiffs Astellas Pharma Inc. et al.

Plaintiffs Astellas and its affiliates have retained a combination of national counsel known for high-stakes pharmaceutical patent litigation and experienced local New Jersey counsel. Filings in this case and the consolidated action (3:24-cv-09403) confirm representation by Williams & Connolly LLP as lead counsel and Saul Ewing LLP as local counsel.

Lead Counsel

• David Berl (Lead Counsel)

  • Firm: Williams & Connolly LLP, Washington, D.C.
  • Note: Co-chair of his firm's Patent Litigation practice, Berl has served as lead counsel in numerous major Hatch-Waxman and other pharmaceutical patent trials for clients including Pfizer, Bayer, and Eli Lilly.

• Dominick A. Conde (Of Counsel)

  • Firm: Venable LLP, New York, NY.
  • Note: While court filings in related, consolidated cases list Conde as "Of Counsel" with a pro hac vice admission forthcoming, his formal appearance in this specific Zydus case is not yet reflected in all public docket entries. He is a veteran first-chair patent trial lawyer with extensive experience in pharmaceutical litigation.

Local Counsel

• Charles M. Lizza (Local Counsel)

  • Firm: Saul Ewing LLP, Newark, NJ.
  • Note: A highly-regarded New Jersey litigator, Lizza concentrates on Hatch-Waxman ANDA litigation and serves on the U.S. District Court of New Jersey's Local Patent Rules Committee.

• William C. Baton (Local Counsel)

  • Firm: Saul Ewing LLP, Newark, NJ.
  • Note: Baton focuses his practice on representing branded pharmaceutical companies in Hatch-Waxman litigation and has served as New Jersey counsel for approximately 20 major pharmaceutical companies.

• Liza M. Walsh (Local Counsel)

  • Firm: Walsh Pizzi O'Reilly Falanga LLP, Newark, NJ.
  • Note: Though listed on the initial and amended complaints, Saul Ewing attorneys Lizza and Baton often appear as primary local counsel for major pharmaceutical companies in New Jersey ANDA cases. The precise division of local counsel roles between the firms may be clarified in subsequent filings.

Additional attorneys from these firms have also likely entered appearances or are working on the matter, though the individuals listed above are identified in key filings and firm biographies as leading the representation.

Counsel for Defendants Zydus Pharmaceuticals (USA) Inc. and Zydus Lifesciences Ltd.

Based on a review of the court docket, the following attorneys have appeared on behalf of the Zydus defendants in this consolidated action.

• Name: Joseph A. Calvaruso

• Role: Lead Counsel

• Firm: Kelley Drye & Warren LLP

• Office Location: Chicago, IL

• Notable Experience: Mr. Calvaruso has extensive experience representing generic pharmaceutical companies in Hatch-Waxman litigation, including prior cases involving major drugs such as Gilenya and Tecfidera.

• Name: Gregory J. Panzarella

• Role: Local Counsel

• Firm: Panzarella & Associates, LLC

• Office Location: Red Bank, NJ

• Notable Experience: Mr. Panzarella frequently serves as New Jersey local counsel for out-of-state firms in complex commercial and intellectual property litigation.

• Name: Jordan F. Cohen

• Role: Of Counsel

• Firm: Kelley Drye & Warren LLP

• Office Location: Chicago, IL

• Notable Experience: Mr. Cohen's practice focuses on intellectual property litigation with an emphasis on the pharmaceutical and biotechnology industries.

• Name: Michael J. Mlotkiewicz

• Role: Of Counsel

• Firm: Kelley Drye & Warren LLP

• Office Location: Chicago, IL

• Notable Experience: Mr. Mlotkiewicz has represented clients in numerous ANDA cases and has experience before both district courts and the Patent Trial and Appeal Board (PTAB).