Array BioPharma v. Teva: MEK Inhibitor Patent Dispute Dismissed Without Prejudice
Array BioPharma filed suit against Teva Pharmaceutical Industries in Delaware District Court asserting three patents covering MEK inhibitor preparations and formulations. After 785 days of litigation, the parties jointly stipulated to dismiss all claims and counterclaims without prejudice under Rule 41(a)(1)(A)(ii), with each side bearing its own costs.
Three MEK Inhibitor Patents, One Stipulated Exit After Two-Plus Years
Array BioPharma, Inc. — a biopharmaceutical company and holder of patents covering MEK inhibitor preparations and formulations — filed this infringement action against Teva Pharmaceutical Industries, Ltd. on June 8, 2023, in the District of Delaware before Judge Gregory B. Williams. The complaint asserted three issued U.S. patents: US9562016B2, US9598376B2, and US9980944B2, all directed at MEK inhibitor compound preparations and pharmaceutical formulations.
On August 1, 2025, the parties jointly filed a stipulation under Fed. R. Civ. P. 41(a)(1)(A)(ii) dismissing all claims and counterclaims without prejudice. Each party was ordered to bear its own costs and fees. A dismissal without prejudice means the underlying merits were never adjudicated — Array preserves the right to reassert the same patents in a future action, subject to applicable limitations and estoppel considerations.
The 785-day duration before a no-merits exit is notable: it suggests the parties engaged in substantial litigation activity — likely including ANDA-related fact development, claim construction, or parallel regulatory proceedings — before reaching resolution. The public record does not disclose whether a licensing arrangement, settlement payment, or commercial agreement accompanied the stipulation, leaving the true driver of dismissal uncertain.
Filing to Dismissed without Prejudice in 785 days
785 days — above the median for pharma patent cases in Delaware, suggesting active pre-trial disputes before resolution
Dismissed without prejudice: what the stipulated exit means for both parties
Rule 41(a)(1)(A)(ii) dismissal: no merits ruling, case closed by consent
A stipulated dismissal under Fed. R. Civ. P. 41(a)(1)(A)(ii) requires agreement from all parties who have appeared. It is procedurally the cleanest exit — no judgment is entered, no court findings bind the parties. Without prejudice means the action can be refiled; neither invalidity nor non-infringement has been adjudicated. The absence of a merits ruling is legally significant for any future enforcement or licensing dispute involving these three patents.
No merits adjudicatedArray retains full enforcement rights on all three patents
Because dismissal is without prejudice, Array BioPharma (now part of Pfizer) preserves the right to reassert US9562016B2, US9598376B2, and US9980944B2 against Teva or any other generic entrant. No adverse finding on validity or infringement limits future enforcement. However, the two-plus-year litigation investment without a judgment means Array received no confirmed exclusivity win from this action. A confidential commercial resolution is possible but unconfirmed on the public record.
Enforcement rights intactTeva exits without an invalidity finding — but faces potential re-litigation
Teva obtains no declaratory judgment of invalidity or non-infringement from this dismissal. While it avoids an adverse judgment, it also gains no preclusive protection. If Teva proceeds with its ANDA or generic launch, the patent holder retains the right to refile, potentially triggering a fresh 30-month stay or injunction proceeding. The each-party-bears-own-costs provision suggests a balanced exit rather than a plaintiff capitulation, consistent with a negotiated resolution.
No preclusive protectionMEK inhibitor generic entry remains legally unresolved for the sector
The without-prejudice dismissal leaves the enforceability of three MEK inhibitor formulation patents unresolved in the public domain. Competing generic manufacturers watching this docket gain no invalidity precedent they can cite. For companies developing or commercializing MEK inhibitor products, these patents remain active enforcement assets. The outcome is consistent with a patent holder maintaining a credible litigation posture while potentially accommodating a specific entrant through a licensing or authorized generic arrangement.
Patents remain enforceableFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Array BioPharma, Inc. | Company | Biopharmaceutical innovator — holder of US9562016B2, US9598376B2, and US9980944B2 (MEK inhibitor formulations)Search in Eureka ↗ |
| Defendant | Teva Pharmaceutical Industries, Ltd. | Company | Global generic pharmaceutical manufacturer and ANDA filer, subsidiary of Teva Pharmaceutical Industries, Ltd.Search in Eureka ↗ |
| Plaintiff counsel | Jack B. Blumenfeld | Attorney | Counsel for Array BioPharma, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Megan Elizabeth Dellinger | Attorney | Counsel for Array BioPharma, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Morris, Nichols, Arsht & Tunnell LLP | Law Firm | Representing Array BioPharma, Inc.Search in Eureka ↗ |
| Defendant counsel | Alexandra D. Valenti | Attorney | Counsel for Teva Pharmaceutical Industries, Ltd.Search in Eureka ↗ |
| Defendant counsel | Andrew Russell | Attorney | Counsel for Teva Pharmaceutical Industries, Ltd.Search in Eureka ↗ |
| Defendant counsel | Christopher J. Cassella | Attorney | Counsel for Teva Pharmaceutical Industries, Ltd.Search in Eureka ↗ |
| Defendant counsel | Daryl L. Wiesen | Attorney | Counsel for Teva Pharmaceutical Industries, Ltd.Search in Eureka ↗ |
| Defendant counsel | Emily DiBenedetto | Attorney | Counsel for Teva Pharmaceutical Industries, Ltd.Search in Eureka ↗ |
| Defendant counsel | Gabriel Ferrante | Attorney | Counsel for Teva Pharmaceutical Industries, Ltd.Search in Eureka ↗ |
| Defendant counsel | Karen Elizabeth Keller | Attorney | Counsel for Teva Pharmaceutical Industries, Ltd.Search in Eureka ↗ |
| Defendant law firm | Shaw Keller LLP | Law Firm | Representing Teva Pharmaceutical Industries, Ltd.Search in Eureka ↗ |
| Presiding judge | Judge Gregory B. Williams | Judge | Delaware District CourtSearch in Eureka ↗ |
Official order — verbatim text
The stipulation language — ‘all claims and counterclaims … are dismissed without prejudice … each party shall bear its own costs’ — is precise and bilateral. The without-prejudice qualifier is legally material: it forecloses any res judicata or collateral estoppel argument based on this proceeding. The symmetric cost allocation, rather than a cost award to either side, is consistent with a mutually negotiated resolution and does not signal a unilateral plaintiff withdrawal. No findings on patent validity, claim scope, or infringement are embedded in this order.
US9562016B2, US9598376B2 & US9980944B2 — MEK Inhibitor Preparations and Formulations
The three patents asserted in this case — US9562016B2, US9598376B2, and US9980944B2 — are directed at the preparation of and formulations comprising a MEK inhibitor, a class of targeted oncology compound that inhibits the MEK1/MEK2 kinase pathway relevant to BRAF-mutant cancers. Array BioPharma’s MEK inhibitor portfolio is closely associated with binimetinib (MEKTOVI), approved in combination with BRAF inhibitor encorafenib. The patents cover composition, formulation, and method-of-preparation claims that are typical of lifecycle management strategies in small-molecule oncology.
From a competitive intelligence standpoint, three co-asserted formulation patents covering the same product class create layered enforcement risk for generic entrants. Even if one patent is designed around or invalidated, the remaining claims can sustain litigation and extend the effective exclusivity window. For Teva and other generic manufacturers, the without-prejudice dismissal means this layered risk remains fully intact. Biosimilar and generic developers active in the oncology MEK/BRAF inhibitor space should treat these patents as live enforcement assets within Pfizer’s post-acquisition portfolio.
Should you run an FTO against US9562016B2, US9598376B2, and US9980944B2?
Any company developing, manufacturing, or commercializing a MEK inhibitor preparation or pharmaceutical formulation — whether as a generic, biosimilar-adjacent product, or novel combination — should assess freedom to operate against these three patents. The dismissal without prejudice in this case does not constitute a clearance opinion. Array’s (now Pfizer’s) enforcement posture remains active, and the absence of an invalidity ruling means these claims have never been tested on the merits in litigation.
PatSnap Eureka’s FTO Search Agent can map the claim scope of US9562016B2, US9598376B2, and US9980944B2 against your compound’s structural and formulation parameters, identify prior art that could support an invalidity argument, and surface related continuation or divisional applications that may extend the risk horizon. R&D teams at the formulation and IND-filing stage should integrate this analysis early to avoid costly design-around exercises at the NDA or ANDA submission stage.
Run a freedom-to-operate analysis on US9562016B2 to assess your product’s exposure
Run FTO in Eureka →Similar MEK Inhibitor and Oncology Formulation Patent Cases in Delaware
Explore related Hatch-Waxman and ANDA patent infringement cases involving oncology formulation patents litigated in the District of Delaware.
What this case signals for the MEK inhibitor and oncology IP landscape
A 785-day without-prejudice exit in Delaware typically signals strategic repositioning, not capitulation — implications extend beyond this single dispute.
Without-prejudice dismissals preserve enforcement optionality — monitor closely
When a branded pharma plaintiff dismisses without prejudice after two-plus years, it often signals a parallel commercial resolution rather than weakness. Companies holding or challenging MEK inhibitor patents should monitor these three patent numbers for reactivated enforcement, licensing demands, or new ANDA-triggered suits against other generic entrants.
Delaware’s ANDA docket remains the primary MEK inhibitor battleground
The District of Delaware under Judge Williams continues to see complex pharma patent disputes. The each-party-bears-own-costs structure and stipulated mechanism suggest counsel reached an efficient exit before trial — a pattern increasingly common in Delaware as dockets remain congested. Practitioners should factor in extended pre-trial timelines when advising on ANDA litigation strategy.
Array v Teva — key questions answered
A dismissal without prejudice means no judgment was entered on the merits. Array BioPharma retains the right to reassert patents US9562016B2, US9598376B2, and US9980944B2 against Teva or any other party in a future action. Neither party received a finding on infringement or invalidity, and no estoppel arises from this proceeding.
Array BioPharma asserted three U.S. patents: US9562016B2, US9598376B2, and US9980944B2. All three cover preparations and formulations comprising a MEK inhibitor, consistent with Array’s binimetinib (MEKTOVI) product and lifecycle management portfolio. The case was filed June 8, 2023, in the District of Delaware.
Rule 41(a)(1)(A)(ii) allows parties to dismiss a case without a court order when all appearing parties sign a stipulation. It is the standard mechanism for a jointly negotiated exit in patent litigation. The public record does not disclose the commercial terms, if any, that accompanied the stipulation — a confidential license or settlement agreement is possible but unconfirmed.
The dismissal does not itself authorize a generic launch. Because it is without prejudice and without any invalidity or non-infringement finding, Teva receives no preclusive protection from the three asserted patents. If Teva proceeds with an ANDA-based launch, the patent holder could refile suit, potentially triggering Hatch-Waxman 30-month stay provisions depending on the timing and procedural posture of any new action.
Array BioPharma was represented by Jack B. Blumenfeld and Megan Elizabeth Dellinger of Morris, Nichols, Arsht & Tunnell LLP — a leading Delaware patent litigation firm. Teva was represented by Alexandra D. Valenti, Andrew Russell, Christopher J. Cassella, Daryl L. Wiesen, Emily DiBenedetto, Gabriel Ferrante, and Karen Elizabeth Keller of Shaw Keller LLP.
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