Axsome v. Alkem, Hikma & Others: 13-Patent Sunosi Infringement Battle in New Jersey
Axsome Malta Ltd. and Axsome Therapeutics, Inc. brought a sweeping ANDA-driven infringement action against seven generic pharmaceutical defendants over Sunosi® (solriamfetol) tablets in the District of New Jersey, asserting 13 patents. After 545 days of litigation, claims against Hikma Pharmaceuticals USA were dismissed without prejudice by stipulation — while claims against the remaining defendants continued.
Multi-defendant Sunosi patent war: Hikma exits without prejudice
Filed on 13 September 2023 in the U.S. District Court for the District of New Jersey, this Hatch-Waxman patent infringement action pits Axsome Malta Ltd. and Axsome Therapeutics, Inc. against seven generic pharmaceutical companies — Alkem Laboratories, Hetero Labs (multiple entities), Aurobindo Pharma USA, Sandoz Inc., Hikma Pharmaceuticals USA, and Unichem Laboratories. At stake are 13 U.S. patents covering Sunosi® (solriamfetol) oral tablets at 75 mg and 150 mg doses, a wakefulness-promoting agent approved for excessive daytime sleepiness associated with narcolepsy and obstructive sleep apnea.
On 11 March 2025, the court entered a stipulated dismissal under Federal Rule of Civil Procedure 41(a)(1)(A)(ii) terminating all claims, counterclaims, and affirmative defenses between Axsome and Hikma Pharmaceuticals USA only. The dismissal was expressly without prejudice and without costs or attorneys’ fees to either party. Critically, the stipulation preserved the court’s jurisdiction to enforce any disputes on the subject matter and explicitly confirmed that dismissal as to Hikma does not affect any remaining claims against the other six defendants.
The 545-day duration before Hikma’s exit is consistent with the statutory 30-month stay under Hatch-Waxman triggering intensive early motion practice. A without-prejudice dismissal of a single defendant in a multi-defendant ANDA case typically suggests a confidential resolution — potentially a licensing agreement or consent judgment — though the public record is silent on specific commercial terms. The fate of claims against Alkem, Hetero, Aurobindo, Sandoz, and Unichem remains open and unresolved as of the case closure date recorded for this docket segment.
Filing to Case Dismissed in 545 days
545 days in active litigation — typical Hatch-Waxman ANDA cases often resolve or reach trial in 24–36 months
Hikma dismissed without prejudice: what the stipulation means for both sides
Rule 41(a)(1)(A)(ii) stipulated dismissal — no merits adjudication
A Rule 41(a)(1)(A)(ii) dismissal requires written consent of all parties who have appeared, making it a negotiated exit rather than a court-decided outcome. Because the dismissal is without prejudice, no final judgment on the merits was entered — Axsome retains the right to re-file infringement claims against Hikma in the future. The court expressly retained jurisdiction over related disputes, which is consistent with an underlying agreement whose terms may require ongoing supervision.
No merits ruling enteredAxsome preserves all 13 patents and re-filing rights against Hikma
A without-prejudice dismissal is structurally favourable to the patent holder in multi-defendant ANDA litigation: Axsome’s 13 patents remain fully in force and unchallenged by any final ruling. Axsome may re-assert claims against Hikma if any agreed conditions are breached. The absence of a costs award neutralises any tactical concession, and the court’s retained jurisdiction suggests ongoing oversight of any commercial arrangement reached between the parties.
Patents intact, re-filing preservedHikma exits without invalidity ruling but faces potential re-litigation
For Hikma, the without-prejudice dismissal means no declaratory judgment of invalidity or non-infringement was obtained. While Hikma avoids immediate litigation cost, it does not receive the ‘clear runway’ that a successful invalidity ruling would provide. Any ANDA approval path for Hikma’s solriamfetol product remains subject to the 13 asserted patents. The public record does not disclose whether Hikma received a licence, agreed to a launch date, or simply settled the litigation without commercial terms.
No invalidity finding secured13-patent fortress signals high barrier to generic solriamfetol entry
Axsome’s 13-patent portfolio covering Sunosi compositions, formulations, and methods of use represents a layered exclusivity strategy common in branded CNS drug protection. With six defendants still in litigation, any resolution with Hikma — whatever its undisclosed terms — does not clear the market. Competitors monitoring this case should note that each of the 13 patents must be independently addressed in any ANDA challenge, and that Axsome has demonstrated willingness to litigate aggressively and in parallel across multiple generic filers.
Multi-layer patent barrier remainsFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Axsome Malta, Ltd. | Company | Pharmaceutical IP licensor and NDA holder — holder of US9604917B2 and 12 related Sunosi patentsSearch in Eureka ↗ |
| Co-Plaintiff | Axsome Therapeutics, Inc. | Company | Search in Eureka ↗ |
| Defendant | Alkem Laboratories, Ltd. | Company | Generic pharmaceutical manufacturers seeking ANDA approval for solriamfetol 75 mg and 150 mg tabletsSearch in Eureka ↗ |
| Co-Defendant | Hetero Labs, Ltd. | Company | Search in Eureka ↗ |
| Co-Defendant | Hetero USA, Inc. | Company | Search in Eureka ↗ |
| Co-Defendant | Hetero Labs Limited | Individual | Search in Eureka ↗ |
| Co-Defendant | Aurobindo Pharma USA, Inc. | Company | Search in Eureka ↗ |
| Co-Defendant | Sandoz, Inc. | Company | Search in Eureka ↗ |
| Co-Defendant | Hikma Pharmaceuticals USA, Inc. | Company | Search in Eureka ↗ |
| Co-Defendant | Unichem Laboratories, Ltd. | Company | Search in Eureka ↗ |
| Plaintiff counsel | Abigail Demasi | Attorney | Counsel for Axsome Malta, Ltd.Search in Eureka ↗ |
| Plaintiff counsel | Alexander Lee Callo | Attorney | Counsel for Axsome Malta, Ltd.Search in Eureka ↗ |
| Plaintiff counsel | Brian John Forsatz | Attorney | Counsel for Axsome Malta, Ltd.Search in Eureka ↗ |
| Plaintiff counsel | Charles Michael Lizza | Attorney | Counsel for Axsome Malta, Ltd.Search in Eureka ↗ |
| Plaintiff counsel | Frank Charles Calvosa | Attorney | Counsel for Axsome Malta, Ltd.Search in Eureka ↗ |
| Plaintiff counsel | Sarah Ann Sullvian | Attorney | Counsel for Axsome Malta, Ltd.Search in Eureka ↗ |
| Plaintiff counsel | William C. Baton | Attorney | Counsel for Axsome Malta, Ltd.Search in Eureka ↗ |
| Plaintiff law firm | QUINN EMANUEL TRIAL LAWYERS | Law Firm | Representing Axsome Malta, Ltd.Search in Eureka ↗ |
| Plaintiff law firm | Quinn Emanuel Urquhart & Sullivan, LLP | Law Firm | Representing Axsome Malta, Ltd.Search in Eureka ↗ |
| Plaintiff law firm | Saul Ewing, LLP | Law Firm | Representing Axsome Malta, Ltd.Search in Eureka ↗ |
| Defendant counsel | Rebekah R. Conroy | Attorney | Counsel for Alkem Laboratories, Ltd.Search in Eureka ↗ |
| Defendant law firm | Stone Conroy LLC | Law Firm | Representing Alkem Laboratories, Ltd.Search in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | New Jersey District CourtSearch in Eureka ↗ |
Official order — verbatim text
The stipulated dismissal order is carefully scoped: it terminates all claims, counterclaims, and affirmative defences between Axsome and Hikma exclusively, and the court expressly confirmed that no other defendant’s position is altered. The without-prejudice designation means the order carries no res judicata effect — neither party is bound by any merits finding, and Axsome retains full re-filing rights. The court’s retention of jurisdiction to resolve disputes relating to the subject matter is a strong textual signal that a private agreement underlies the dismissal, though its commercial terms are not disclosed in the public record.
US9604917B2 — solriamfetol compositions and 12 further Sunosi patents
The 13 patents asserted in this case — spanning application numbers from US11/921995 (corresponding to US8440715B2, an early-stage filing) through US17/212079 (US11648232B2) — collectively protect Axsome’s Sunosi® (solriamfetol) franchise across multiple layers: compound compositions, pharmaceutical formulations, methods of treatment, and dosage forms. Solriamfetol is a dopamine and norepinephrine reuptake inhibitor approved by the FDA for excessive daytime sleepiness in adults with narcolepsy or obstructive sleep apnea. The breadth of the patent estate — 13 granted U.S. patents — reflects a multi-year prosecution strategy designed to extend market exclusivity well beyond any single patent’s expiry.
For competing generic manufacturers, this patent portfolio presents a significant challenge: each of the 13 patents must be individually addressed in ANDA Paragraph IV certifications, and the overlapping claim scope across composition, formulation, and method patents means that designing around one patent does not necessarily clear a path to market. The involvement of major generic filers — including Sandoz, Hikma, Aurobindo, and Hetero — confirms that solriamfetol is viewed as a commercially valuable target. Axsome’s willingness to name seven defendants simultaneously and pursue parallel litigation across all signals a high-enforcement posture that should be factored into any generic development programme.
Should you run an FTO against the Sunosi solriamfetol patent portfolio?
Any company developing, formulating, or seeking ANDA approval for solriamfetol oral tablets at any dose strength should treat this 13-patent estate as a priority FTO target. The portfolio spans compound, salt, formulation, and method claims — meaning a freedom-to-operate analysis must go beyond the lead composition patent and address each granted patent individually. R&D teams working on wakefulness-promoting CNS agents with structural similarity to solriamfetol should also assess whether their candidate compounds fall within the scope of the broader method-of-treatment claims in this portfolio.
PatSnap Eureka’s FTO Search Agent can map each of the 13 asserted patents against your product’s proposed formulation, dosing regimen, and synthesis route, identifying claim elements that require design-around or licensing attention. Eureka’s claim-charting tools allow side-by-side comparison of your ANDA product specification against the independent claims of all 13 patents simultaneously — dramatically reducing the time and cost of manual FTO analysis for complex multi-patent pharmaceutical portfolios like Axsome’s Sunosi estate.
Run a freedom-to-operate analysis on US9604917B2 to assess your product’s exposure
Run FTO in Eureka →Similar Hatch-Waxman solriamfetol and CNS pharma patent cases
Explore related ANDA patent infringement cases in the District of New Jersey and other jurisdictions involving CNS wakefulness agents, solriamfetol, and multi-patent branded drug defences.
What this case signals for the CNS and generic pharma IP landscape
A 13-patent ANDA defence with six simultaneous defendants sets a benchmark for branded CNS drug exclusivity strategy.
Multi-defendant ANDA filings demand coordinated, patent-by-patent defence planning
With seven defendants named simultaneously, Axsome’s litigation approach mirrors an increasingly common branded pharma tactic: forcing generic challengers to coordinate or separately litigate invalidity across a large patent estate. IP teams at generic manufacturers should conduct granular patent-by-patent FTO analysis before filing any ANDA against a drug protected by 10+ patents, as even partial invalidity findings may not clear a path to market.
Without-prejudice exits in Hatch-Waxman cases often signal confidential licensing
When a generic defendant exits a multi-party ANDA suit via Rule 41 without prejudice and with no costs — as Hikma did here — this pattern is strongly consistent with an authorised generic agreement or a negotiated launch date, though the public record is silent. IP and business development teams at both branded and generic companies should treat such dismissals as potential market-timing signals rather than clean legal victories.
Axsome v Alkem — key questions answered
Axsome Malta Ltd. and Axsome Therapeutics, Inc. asserted 13 U.S. patents in Case 2:23-cv-20354, including US9604917B2, US10940133B1, US10959976B2, US10195151B2, US10512609B2, US11439597B2, US11648232B2, US11560354B2, US10351517B2, US8877806B2, US8440715B2, US10912754B2, and US11160779B2, all covering aspects of solriamfetol (Sunosi®) compositions, formulations, and methods of treatment.
The dismissal of claims against Hikma Pharmaceuticals USA was entered pursuant to a Rule 41(a)(1)(A)(ii) stipulation — a consensual, negotiated exit requiring agreement of both parties. A without-prejudice dismissal means no merits ruling was made; the public record does not disclose the commercial terms, but this structure is consistent with a licensing arrangement or agreed launch date. Axsome retains the right to re-file claims against Hikma.
No. The stipulated dismissal order expressly states that dismissal as to Hikma does not result in dismissal of any claims, defences, or counterclaims with respect to any other defendant. Litigation against Alkem Laboratories, Hetero Labs, Aurobindo Pharma USA, Sandoz Inc., and Unichem Laboratories continues on the same 13-patent docket.
Sunosi® (solriamfetol) is an FDA-approved dopamine and norepinephrine reuptake inhibitor indicated for excessive daytime sleepiness in adults with narcolepsy or obstructive sleep apnea. As a branded prescription drug with commercial value, it is subject to Hatch-Waxman ANDA challenges by generic manufacturers seeking to launch lower-cost equivalents. Axsome’s 13-patent portfolio is designed to block or delay such generic entry.
The stipulation expressly provides that the U.S. District Court for the District of New Jersey retains jurisdiction to enforce and resolve any disputes relating to the subject matter of the action. This is a strong signal that an underlying agreement — potentially a settlement, licence, or consent judgment — governs the Axsome-Hikma relationship post-dismissal. Retained jurisdiction allows either party to return to the court if the other breaches agreed terms, without initiating a new lawsuit.
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