Janssen v. Sun Pharma: Invega Sustenna® Patent Dispute Dismissed Without Prejudice
Janssen Pharmaceuticals filed suit against Sun Pharmaceutical Industries in the Delaware District Court asserting US9439906B2, covering its Invega Sustenna® paliperidone palmitate extended-release injectable suspension. The action was voluntarily dismissed without prejudice after just 110 days — leaving enforcement options open for a potential refiling.
A Strategic Exit: Janssen’s Without-Prejudice Withdrawal Against Sun Pharma
On July 10, 2025, Janssen Pharmaceuticals, Inc. initiated patent infringement proceedings against Sun Pharmaceutical Industries, Inc. in the United States District Court for the District of Delaware (Case No. 1:25-cv-00857). The suit asserted US9439906B2, a patent tied to Janssen’s branded Invega Sustenna® paliperidone palmitate extended-release injectable suspension — a long-acting antipsychotic product used in the treatment of schizophrenia. The case was assigned to Judge William C. Bryson, a Federal Circuit judge sitting by designation with extensive experience in pharmaceutical patent disputes.
The action was terminated on October 28, 2025 — just 110 days after filing — when Janssen invoked Fed. R. Civ. P. 41(a)(1)(A)(i) to voluntarily dismiss the case without prejudice. This procedural mechanism, available before the defendant serves an answer or a motion for summary judgment, allows the plaintiff to exit without a merits adjudication and, critically, without the dismissal operating as a bar to future litigation on the same claims. The public record does not disclose any settlement agreement, licensing arrangement, or consent order accompanying the dismissal.
The 110-day duration and pre-answer timing of the dismissal suggest the withdrawal occurred at an early procedural stage, before significant litigation costs were incurred by either party. What drove the strategic retreat is not evident from the public docket — possibilities include ongoing ANDA negotiations, a parallel IPR or regulatory development affecting Invega Sustenna®, or an undisclosed commercial resolution. Because the dismissal was without prejudice, Janssen retains the ability to assert US9439906B2 against Sun Pharma again, meaning this case may represent a pause rather than a final resolution.
Filing to Voluntary dismissal in 110 days
110 days — shorter than the median ANDA patent dispute lifecycle in Delaware
Voluntarily dismissed: what Rule 41 without prejudice means for both parties
Rule 41(a)(1)(A)(i): plaintiff’s unilateral exit before answer
Fed. R. Civ. P. 41(a)(1)(A)(i) permits a plaintiff to dismiss an action without a court order if filed before the defendant serves an answer or a motion for summary judgment. The dismissal is effective upon filing and carries no merits ruling. Critically, without-prejudice status means the dismissal does not constitute an adjudication on the merits — the same claims can be reasserted in a future action.
No merits rulingWithout prejudice vs. with prejudice: the public record is silent on terms
A ‘with prejudice’ dismissal would permanently bar Janssen from relitigating the same patent claims against Sun Pharma on this product — effectively a defendant win. A ‘without prejudice’ dismissal imposes no such bar, preserving Janssen’s enforcement rights. The filed notice confirms this dismissal is without prejudice. However, whether any side agreement — such as a licensing term, covenant not to sue, or standstill — underpins this exit is not disclosed in the public docket.
Refiling rights preservedJanssen exits with enforcement rights intact over US9439906B2
Janssen’s voluntary withdrawal without prejudice leaves its patent position undisturbed. US9439906B2 has not been challenged on its merits, invalidated, or subjected to any adverse ruling. Janssen retains the option to reassert this patent against Sun Pharma — or against other ANDA filers — in future proceedings. The early exit may reflect a tactical recalibration rather than any weakness in the underlying patent.
Patent remains enforceableSun Pharma escapes judgment but faces ongoing patent uncertainty
Sun Pharma obtains no declaratory judgment of invalidity or non-infringement. While the immediate litigation threat is removed, the without-prejudice nature of the dismissal means Sun Pharma cannot treat this case as resolving the patent risk. Any commercial launch of a generic paliperidone palmitate injectable product would still carry exposure to renewed infringement claims under US9439906B2, assuming the patent remains in force.
Patent risk unresolvedFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Janssen Pharmaceuticals, Inc. | Company | Pharmaceutical innovator — holder of US9439906B2 (paliperidone palmitate injectable)Search in Eureka ↗ |
| Defendant | Sun Pharmaceutical Industries, Inc. | Company | Generic pharmaceutical manufacturer and ANDA applicant challenging Invega Sustenna® formulation patentsSearch in Eureka ↗ |
| Plaintiff counsel | Jeremy A. Tigan | Attorney | Counsel for Janssen Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Morris, Nichols, Arsht & Tunnell LLP | Law Firm | Representing Janssen Pharmaceuticals, Inc.Search in Eureka ↗ |
| Presiding judge | Judge William C. Bryson | Judge | Delaware District CourtSearch in Eureka ↗ |
Official order — verbatim text
The dismissal notice invokes Rule 41(a)(1)(A)(i), confirming this was a plaintiff-initiated, pre-answer exit requiring no judicial approval. The explicit ‘without prejudice’ designation is the operative legal term: it forecloses any argument that the dismissal bars future litigation under res judicata. No admission of invalidity, non-infringement, or unenforceability attaches to the patent. For Sun Pharma, the absence of a court-endorsed resolution leaves the competitive landscape unchanged in legal terms.
US9439906B2 — Paliperidone Palmitate Extended-Release Injectable Suspension
US9439906B2 (application number US12/337144) protects formulations of paliperidone palmitate configured as an extended-release injectable suspension — the active ingredient in Janssen’s branded Invega Sustenna® product. Paliperidone palmitate is a long-acting injectable (LAI) atypical antipsychotic administered monthly, offering a compliance-focused alternative to daily oral antipsychotics in the treatment of schizophrenia. The patent’s formulation claims are typical of second-generation antipsychotic LAI protection strategies, targeting particle size, aqueous suspension composition, and release-rate characteristics.
For generic manufacturers, US9439906B2 represents a meaningful market-exclusivity barrier in the multi-billion-dollar LAI antipsychotic segment. Invega Sustenna® has been a cornerstone of Janssen’s neuroscience portfolio, and ANDA-driven challenges to its patent estate are commercially high-stakes. Any biosimilar or generic injectable suspension referencing Invega Sustenna® must navigate this patent alongside the broader Orange Book-listed estate. The without-prejudice dismissal in this case means the patent has not been subjected to any validity or infringement adjudication, leaving its enforceability status fully intact.
Should you run an FTO analysis against US9439906B2?
Any pharmaceutical company developing, formulating, or seeking ANDA approval for a paliperidone palmitate extended-release injectable suspension product should treat US9439906B2 as a live FTO risk. The voluntary dismissal of this case against Sun Pharma without prejudice does not constitute a covenant not to sue and does not resolve infringement exposure. R&D teams working on LAI atypical antipsychotic platforms — including particle engineering, aqueous suspension systems, or monthly injectable depot formulations — should commission a claim-level FTO analysis before advancing to IND or ANDA filing stages.
PatSnap Eureka’s FTO Search Agent can map the claim scope of US9439906B2 against your specific formulation parameters, flag related continuations or divisionals in the Janssen portfolio, and surface prior art that may be relevant to validity. Eureka’s litigation monitoring layer will also alert you to any re-filing by Janssen against Sun Pharma or other defendants, giving your team early warning of enforcement activity in the paliperidone palmitate injectable space.
Run a freedom-to-operate analysis on US9439906B2 to assess your product’s exposure
Run FTO in Eureka →Similar ANDA Patent Disputes Involving Long-Acting Injectable Antipsychotics
Explore related patent infringement cases in the paliperidone palmitate and LAI antipsychotic space litigated in the Delaware District Court.
What this case signals for the long-acting injectable antipsychotic IP landscape
Janssen’s swift Rule 41 exit preserves optionality — a pattern worth tracking across the paliperidone palmitate ANDA litigation cycle.
Pre-answer dismissals in ANDA cases often signal off-docket negotiations
When a branded pharmaceutical company voluntarily dismisses an ANDA patent suit within 110 days — before the defendant even answers — it typically suggests either a licensing discussion, a regulatory development, or a strategic decision to pursue a stronger venue or timing. IP teams monitoring Invega Sustenna® generics should watch for follow-on filings.
US9439906B2 remains an active enforcement risk for paliperidone palmitate generics
The without-prejudice dismissal leaves the patent unchallenged on its merits. Any generic manufacturer or ANDA applicant seeking to commercialise a paliperidone palmitate extended-release injectable product should treat this patent as an unresolved FTO risk. The absence of a judgment does not equal clearance.
Janssen v Sun — key questions answered
Janssen asserted US9439906B2, which covers paliperidone palmitate extended-release injectable suspension formulations — the active ingredient in its branded Invega Sustenna® product. The application number on record is US12/337144.
The public record does not disclose the reason for the dismissal. Janssen invoked Fed. R. Civ. P. 41(a)(1)(A)(i), a procedural mechanism available before the defendant files an answer. Common drivers include off-docket licensing negotiations, regulatory developments, or tactical timing considerations. No settlement or agreement is publicly recorded.
No. A dismissal without prejudice explicitly preserves the plaintiff’s right to refile. Janssen can reassert US9439906B2 against Sun Pharma in a future action. The patent itself has not been adjudicated on validity or infringement, and no covenant not to sue is on record.
Sun Pharma obtained no declaratory judgment of non-infringement or invalidity. The patent risk from US9439906B2 remains legally unresolved. Any commercial launch of a generic paliperidone palmitate injectable suspension would still carry potential exposure to renewed infringement claims by Janssen under this patent, assuming it remains in force.
The case was assigned to Judge William C. Bryson of the Delaware District Court. Judge Bryson is a former Federal Circuit judge sitting by designation, bringing significant appellate-level pharmaceutical patent expertise to the case.
PatSnap Eureka searches patents and litigation data to answer instantly.