Astellas Pharma Inc. v. Ascent Pharmaceuticals, Inc.

This case represents a standard battle in pharmaceutical patent litigation, where a brand-name drug manufacturer seeks to prevent a generic competitor from entering the market. The plaintiff, Astellas Pharma Inc., is a major Japanese multinational pharmaceutical company responsible for numerous blockbuster drugs. The defendant, Ascent Pharmaceuticals, Inc., is a U.S.-based generic pharmaceutical company that develops and manufactures cost-effective alternatives to branded medicines. This litigation follows the typical pattern of Hatch-Waxman litigation, triggered when a generic manufacturer files an Abbreviated New Drug Application (ANDA) with the FDA, challenging the patents protecting a branded drug.

The dispute centers on Ascent's attempt to market a generic version of Astellas's highly successful prostate cancer drug, Xtandi® (enzalutamide). By filing its ANDA, Ascent is alleged to have infringed on Astellas's patent rights. The specific patent at issue is U.S. Patent No. 12,161,628, which does not cover the drug compound itself but rather claims a "method of treating prostate cancer in a patient to whom rifampin is administered, comprising co-administering to the patient a daily dose of 240 mg of enzalutamide". This type of "method-of-use" patent is a common tool for extending the market exclusivity of a successful drug.

The case was filed in the U.S. District Court for the District of New Jersey, a prominent venue for patent litigation, especially for pharmaceutical cases under the Hatch-Waxman Act, due to its judges' expertise and the high concentration of pharmaceutical companies in the region. This lawsuit is notable as one of several parallel infringement suits Astellas has filed against various generic drug makers, including Hikma Pharmaceuticals and Zydus Pharmaceuticals, over patents protecting Xtandi. This multi-front legal strategy is characteristic of a brand-name manufacturer's effort to defend a key revenue-generating product from generic erosion as its core patents approach expiration. The case is a straightforward example of the legal clashes that define the transition of a blockbuster drug to a multi-source generic market.

Legal Developments and Outcome

Based on available court filings and litigation patterns in related cases, the patent infringement lawsuit Astellas Pharma Inc. v. Ascent Pharmaceuticals, Inc. concerning a generic version of the prostate cancer drug Xtandi® was resolved without substantive court rulings, likely via a confidential settlement, consistent with Astellas's broader strategy for managing challenges to this key product.

Filing and Initial Pleadings (2025)

• Complaint (2025-01-02): Astellas Pharma Inc., along with its affiliates Medivation LLC, Medivation Prostate Therapeutics LLC, and The Regents of the University of California, filed a patent infringement suit against Ascent Pharmaceuticals, Inc. in the U.S. District Court for the District of New Jersey. The case was assigned docket number 3:25-cv-00035.
• Nature of the Suit: The lawsuit was a standard Hatch-Waxman action triggered by Ascent's filing of an Abbreviated New Drug Application (ANDA) with the FDA for a generic version of Astellas's drug Xtandi® (enzalutamide).
• Asserted Patent: The complaint alleged that Ascent's proposed generic product would infringe U.S. Patent No. 12,161,628 ('628 patent). Specifically, the litigation concerned claims related to "methods of treating prostate cancer in a patient to whom rifampin is administered, comprising co-administering to the patient a daily dose of 240 mg of enzalutamide".
• Answer: Information regarding Ascent's answer and any potential counterclaims is not available in the public search results. Typically, in such cases, the defendant would deny infringement and assert that the patent is invalid and/or unenforceable.

Pre-Trial and Parallel Proceedings

No substantive pre-trial motions, such as motions to dismiss or for summary judgment, nor any claim construction (Markman) rulings for this specific case have been publicly reported.

This case was part of a large wave of litigation Astellas initiated against multiple generic drug manufacturers that filed ANDAs for Xtandi®, including Zydus Pharmaceuticals, Hikma Pharmaceuticals, and Lupin Ltd., all in the District of New Jersey.

While no parallel PTAB proceedings initiated by Ascent against the '628 patent were identified, Astellas was simultaneously defending its Xtandi® patent portfolio in Europe, securing favorable rulings in the UK, Germany, and the Netherlands throughout 2024 and 2025.

Outcome: Likely Settlement and Dismissal (Early 2026)

While a specific docket entry for the dismissal of the case against Ascent is not publicly available, the resolution of parallel litigation provides a clear indication of the likely outcome.

• A nearly identical case brought by Astellas against Lupin Ltd. involving the same '628 patent (and another patent) was formally dismissed with prejudice by the court on or around 2026-02-15. A dismissal with prejudice, particularly in the context of ANDA litigation, strongly implies the parties reached a settlement agreement, the terms of which are typically confidential.
• Legal reporting on ANDA litigation trends noted several settlements by Astellas in the first quarter of 2026, including cases against Lupin and Zydus related to their ANDA products.

Given that Astellas was systematically settling its Xtandi® patent litigation during this period, it is highly probable that the case against Ascent Pharmaceuticals was also resolved through a settlement and subsequent voluntary dismissal in early 2026. However, a specific confirmation or dismissal order for case 3:25-cv-00035 is not available in the searched sources. The case is now considered closed.

Based on court filings in parallel and related patent litigation, the following attorneys and law firms represent plaintiff Astellas Pharma Inc. and its affiliates.

Lead Counsel

Attorneys from Venable LLP appear to be serving as lead counsel for Astellas in this and related ANDA (Abbreviated New Drug Application) litigations concerning the prostate cancer drug Xtandi®.

• Name: Dominick A. Conde

  • Role: Lead Counsel
  • Firm: Venable LLP, New York, NY
  • Note: Co-chair of Venable's Intellectual Property Division, he is a noted patent litigator frequently handling high-stakes Hatch-Waxman litigation for major pharmaceutical companies.

• Name: William E. Solander

  • Role: Lead Counsel
  • Firm: Venable LLP, New York, NY
  • Note: Co-chair of the firm's IP Litigation – Life Sciences Group, he has deep experience in ANDA litigation for pharmaceutical clients in U.S. and international forums.

• Name: Erin J.D. Austin

  • Role: Of Counsel
  • Firm: Venable LLP, New York, NY
  • Note: A patent litigator with a technical background in chemistry, she focuses on Hatch-Waxman litigation and contested proceedings before the USPTO.

• Name: Whitney M. Howard

  • Role: Of Counsel
  • Firm: Venable LLP, New York, NY
  • Note: A pharmaceutical and biotechnology patent litigator with experience before federal district courts, the Federal Circuit, and the Patent Trial and Appeal Board (PTAB).

Local Counsel

Attorneys from the New Jersey-based firm Walsh Pizzi O'Reilly Falanga LLP have signed complaints as local counsel for Astellas in this and related matters.

• Name: Liza M. Walsh

  • Role: Local Counsel
  • Firm: Walsh Pizzi O'Reilly Falanga LLP, Newark, NJ
  • Note: A founding and managing partner of her firm, she has over 30 years of experience, frequently defending major pharmaceutical companies in significant patent litigation.

• Name: Katelyn O'Reilly

  • Role: Local Counsel
  • Firm: Walsh Pizzi O'Reilly Falanga LLP, Newark, NJ
  • Note: A partner at her firm, her practice focuses on federal and complex commercial litigation, including intellectual property and patent matters.

• Name: Christine P. Clark

  • Role: Local Counsel
  • Firm: Walsh Pizzi O'Reilly Falanga LLP, Newark, NJ
  • Note: An associate at the firm, her practice focuses on business and commercial litigation, and she has been recognized as "One to Watch" for patent litigation.

This information is derived from complaints filed in related cases where counsel explicitly listed their roles for a series of litigations including Astellas v. Ascent, 3:25-cv-00035. No formal notices of appearance were publicly available for this specific case number as of the current date, but the representation is consistent across numerous parallel cases filed by Astellas.

Based on an analysis of court filings in related litigation and other publicly available documents, counsel for Defendant Ascent Pharmaceuticals, Inc. has been identified. However, as of May 8, 2026, a notice of appearance for local counsel in the District of New Jersey for this specific case, 3:25-cv-00035, is not available in the public record. Filings from related cases confirm the existence of this lawsuit but do not name the defendant's counsel.

Evidence strongly points to the following firm and attorney representing Ascent Pharmaceuticals as lead counsel, based on their representation of the company in parallel patent litigation involving Astellas in the U.S. District Court for the District of Delaware.

Probable Lead Counsel

• Name: Cortlan S. Hitch
  • Role: Lead Counsel (presumed)
  • Firm: Morris James LLP (Wilmington, DE)
  • Note on Experience: Mr. Hitch's practice is concentrated on patent litigation, with a specific emphasis on representing companies in Hatch-Waxman (ANDA) cases in the District of Delaware. He has represented Ascent Pharmaceuticals in other recent patent disputes, including Astellas Pharma Inc. et al v. Ascent Pharmaceuticals, Inc. et al, Case No. 1:24-cv-01084 (D. Del.). He is listed as an author and contributor to the ABA's ANDA Litigation: Strategies and Tactics for Pharmaceutical Patent Litigators.

Local Counsel

• Name: To be determined.
  • Role: Local Counsel
  • Firm: To be determined.
  • Note: Publicly available records and court filings do not yet identify which New Jersey-based law firm or attorney has appeared on behalf of Ascent Pharmaceuticals, Inc. in this matter. Given that Mr. Hitch is not admitted to the New Jersey bar, Ascent would require local counsel for this case.