Astellas v. Qilu Pharmaceutical: Xtandi® Enzalutamide Patent Dispute Dismissed With Prejudice
Astellas Pharma, Medivation, and the University of California Regents filed suit against Qilu Pharmaceutical in New Jersey over two patents protecting enzalutamide (Xtandi®), a blockbuster prostate cancer therapy. The case closed in just 139 days, with all claims and counterclaims dismissed with prejudice — and each party bearing its own costs — strongly suggesting a confidential settlement.
Xtandi® ANDA battle ends fast: a settlement signal in a high-stakes oncology patent fight
On 1 August 2024, Astellas Pharma Inc., Astellas Pharma US Inc., Astellas US LLC, Medivation LLC, Medivation Prostate Therapeutics LLC, and The Regents of the University of California filed a patent infringement action in the United States District Court for the District of New Jersey against Qilu Pharmaceutical (Hainan) Co., Ltd. and Qilu Pharma, Inc. The plaintiffs alleged infringement of US7709517B2 and US11839689B2 — patents covering enzalutamide compositions and related methods — based on Qilu’s ANDA No. 219140 seeking FDA approval for generic enzalutamide 40 mg and 80 mg tablets, referencing Astellas’s branded Xtandi® product.
The case was terminated on 18 December 2024, 139 days after filing, via a court-issued dismissal order entered at the joint request of all parties. Under that order, each of the plaintiffs’ infringement claims and each of Qilu’s counterclaims — including any invalidity or non-infringement challenges to the patents-in-suit — were dismissed with prejudice. The court simultaneously confirmed it retains jurisdiction to enforce the terms of the parties’ settlement agreement, making explicit that a confidential agreement underlies the dismissal.
The 139-day resolution is notably swift for Hatch-Waxman ANDA litigation, which typically triggers a statutory 30-month stay and multi-year proceedings. The mutual dismissal with prejudice and explicit retention of settlement enforcement jurisdiction strongly suggests the parties negotiated an agreed entry date or licensing arrangement for Qilu’s generic product — a resolution structure common in branded-generic oncology disputes. Critically, the order expressly preserves Qilu’s right to maintain its Paragraph IV certification and prohibits no FDA action on ANDA No. 219140, meaning approval remains available to Qilu under whatever timeline the settlement dictates.
Filing to Dismissed with Prejudice in 139 days
139 days — well below the typical 2–4 year ANDA patent litigation timeline in district court
Dismissed with prejudice: what the Qilu settlement order means for both parties
Dismissal with prejudice signals a negotiated resolution
A dismissal with prejudice under a joint request — with the court expressly retaining jurisdiction to enforce a settlement agreement — is the hallmark of a Hatch-Waxman negotiated exit. Neither party can refile these specific claims. The finality is mutual: Astellas cannot re-sue on these patents for this ANDA; Qilu cannot relitigate its counterclaims. The settlement agreement itself remains confidential but is legally enforceable by the court.
Settlement-driven dismissalAstellas and UC Regents protect Xtandi® without a merits ruling
Plaintiffs avoided any court ruling on patent validity or infringement — preserving both patents’ presumptive validity. In ANDA litigation, branded companies often prefer settlement to a judgment that could invalidate claims and open the market to all generics. By settling, Astellas and the UC Regents retain full enforcement rights against other ANDA filers and likely control Qilu’s market entry date through the confidential agreement.
Patents intact, entry date controlledQilu preserves its ANDA and Paragraph IV certification
The dismissal order expressly states that Qilu may maintain its Paragraph IV certification and that FDA may grant final approval to ANDA No. 219140 at any time. This means Qilu has not surrendered its path to market — only its ability to re-litigate these specific patent claims. An agreed entry date negotiated in the settlement is the most commercially logical explanation for Qilu accepting a with-prejudice dismissal of its counterclaims so quickly.
ANDA and approval pathway preservedConfidential entry date deals define branded oncology generics risk
Xtandi® (enzalutamide) is a multi-billion-dollar androgen receptor inhibitor. ANDA settlements with agreed entry dates shift generic competition risk from litigation outcomes to contractual terms. Other ANDA filers for enzalutamide face a stronger litigation posture from Astellas: no adverse ruling on US7709517B2 or US11839689B2 has been entered, and both patents remain fully enforceable. Competing generic entrants should monitor Qilu’s agreed entry date as a signal for broader market opening.
Agreed entry date risk for sectorFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Astellas Pharma, Inc. | Company | Pharmaceutical and university patent holders of enzalutamide (Xtandi®) composition patentsSearch in Eureka ↗ |
| Co-Plaintiff | The Regents of the University of California | Individual | Search in Eureka ↗ |
| Co-Plaintiff | Astellas Pharma US, Inc. | Company | Search in Eureka ↗ |
| Co-Plaintiff | Astellas US, LLC | Company | Search in Eureka ↗ |
| Co-Plaintiff | Medivation, LLC | Company | Search in Eureka ↗ |
| Co-Plaintiff | Medivation Prostate Therapeutics, LLC | Company | Search in Eureka ↗ |
| Defendant | QILU PHARMACEUTICAL (HAINAN) CO., LTD. | Company | Chinese generic pharmaceutical company seeking FDA approval for enzalutamide tablets via ANDASearch in Eureka ↗ |
| Co-Defendant | Qilu Pharma, Inc. | Company | Search in Eureka ↗ |
| Plaintiff counsel | Christine Clark | Attorney | Counsel for Astellas Pharma, Inc.Search in Eureka ↗ |
| Plaintiff counsel | ERIN AUSTIN | Attorney | Counsel for Astellas Pharma, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Katelyn O’Reilly | Attorney | Counsel for Astellas Pharma, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Liza M. Walsh | Attorney | Counsel for Astellas Pharma, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Venable, LLP | Law Firm | Representing Astellas Pharma, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Walsh Pizzi O’reilly Falanga, LLP | Law Firm | Representing Astellas Pharma, Inc.Search in Eureka ↗ |
| Defendant counsel | Ian Scott | Attorney | Counsel for QILU PHARMACEUTICAL (HAINAN) CO., LTD.Search in Eureka ↗ |
| Defendant law firm | Taft, Stettinius & Hollister LLP | Law Firm | Representing QILU PHARMACEUTICAL (HAINAN) CO., LTD.Search in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | New Jersey District CourtSearch in Eureka ↗ |
Official order — verbatim text
The dismissal order, entered at the joint request of all parties, operates as a full bilateral closure of the litigation without any merits determination. The with-prejudice standard bars refiling of both the plaintiffs’ infringement claims and Qilu’s counterclaims — including any invalidity challenges to US7709517B2 and US11839689B2. The court’s explicit retention of jurisdiction to enforce the settlement agreement confirms a binding private arrangement governs post-dismissal obligations, most likely an agreed entry date for Qilu’s generic enzalutamide. The cost-neutrality provision (each party bears its own costs) is consistent with a balanced negotiated outcome rather than a concession by either side.
US7709517B2 & US11839689B2 — Enzalutamide androgen receptor inhibitor patents
US7709517B2 (application no. US11/433829) covers foundational enzalutamide compositions — a potent androgen receptor (AR) inhibitor used in the treatment of metastatic castration-resistant prostate cancer (mCRPC). US11839689B2 (application no. US17/985235) represents a later-generation patent, likely covering formulations, methods of use, or additional therapeutic indications, extending protection further into the patent lifecycle. Together, these patents underpin Astellas’s Xtandi® franchise, one of the highest-revenue oncology products globally.
Xtandi® has generated billions in annual global revenue, making its patent portfolio a primary enforcement target as the drug approaches generic eligibility. The involvement of both Astellas/Medivation (commercial rights holders) and the University of California Regents (originating academic inventors) reflects the co-ownership structure typical of university-industry pharmaceutical partnerships. Any competitor seeking to enter the enzalutamide market via ANDA must evaluate both patents’ claim scope across compositions, formulations, and method-of-treatment claims — all of which remain fully valid and enforceable following this dismissal.
Should you run an FTO against US7709517B2 and US11839689B2?
Any pharmaceutical company or generic manufacturer planning to develop, file an ANDA for, or commercialise enzalutamide tablets in the United States should treat both US7709517B2 and US11839689B2 as live enforcement risks. Neither patent faced a court invalidity ruling in this case. Product teams working on androgen receptor inhibitors, prostate cancer generics, or related oncology compounds should assess freedom to operate before ANDA submission — particularly given Astellas’s demonstrated willingness to file rapidly in New Jersey.
PatSnap Eureka’s FTO Search Agent can map both patents’ claim trees against your compound and formulation data, flag prosecution history estoppel risks, and surface any continuation or divisional applications that extend the family. Eureka also tracks all active ANDA filings and related Paragraph IV certifications for enzalutamide, so your IP and regulatory teams see the full competitive picture — not just the litigation snapshot.
Run a freedom-to-operate analysis on US7709517B2 to assess your product’s exposure
Run FTO in Eureka →Similar Hatch-Waxman ANDA cases: oncology patent disputes in New Jersey
Explore comparable ANDA patent infringement actions involving oncology blockbusters litigated in New Jersey District Court, including prostate cancer and androgen receptor inhibitor disputes.
What this case signals for the oncology generics IP landscape
Rapid ANDA settlements on blockbuster oncology drugs carry structured risk for every subsequent generic filer and product team.
Fast ANDA dismissals with prejudice almost always mean negotiated entry dates
When an ANDA case resolves with prejudice in under 140 days — and the court retains settlement-enforcement jurisdiction — a confidential agreed-entry-date arrangement is the near-universal explanation. Generic companies and patent monitors should treat this dismissal as a market-access event, not just a legal closure. Watch for Qilu’s ANDA No. 219140 approval notice for timing signals.
Both Xtandi® patents survive without any adverse validity ruling
Neither US7709517B2 nor US11839689B2 faced a merits determination. Astellas and the UC Regents can assert both patents at full strength against the next ANDA filer. R&D teams and competing generic manufacturers planning enzalutamide market entry must conduct fresh FTO analysis against both patents — no prior court finding limits their enforceability.
Astellas v QILU — key questions answered
Astellas, Medivation, and the UC Regents asserted two patents: US7709517B2 and US11839689B2, both covering enzalutamide — the active ingredient in Xtandi® — including androgen receptor inhibitor compositions and therapeutic methods for prostate cancer treatment.
The joint request for dismissal with prejudice, combined with the court’s express retention of jurisdiction to enforce the parties’ settlement agreement, strongly indicates the parties reached a confidential out-of-court resolution — most likely an agreed entry date for Qilu’s generic enzalutamide product. Rapid resolution is common in ANDA cases where a negotiated market-entry timeline is commercially preferable to patent validity litigation.
Yes. The dismissal order expressly states that nothing in it prevents Qilu from maintaining its Paragraph IV certification for the patents-in-suit in ANDA No. 219140, and the FDA is not prohibited from granting final approval at any time. Qilu’s regulatory path to market remains open under whatever timeline the confidential settlement dictates.
A mutual cost-bearing provision is consistent with a balanced negotiated settlement in which neither side conceded fault or defeat. In ANDA litigation, fee-shifting awards are rare absent exceptional-case findings. Here, the cost-neutrality clause suggests the parties treated the resolution as a commercial compromise rather than a litigation win or loss for either side.
Yes. Because the case was dismissed without any merits ruling on validity or infringement, both patents retain their full presumption of validity. No claim has been cancelled, limited, or invalidated by this proceeding. Astellas and the UC Regents can assert both patents at full strength against any other ANDA filer seeking to commercialise enzalutamide in the United States.
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