Axsome Malta v. Hetero USA: Solriamfetol Patent Action Dismissed Without Prejudice
Axsome Malta Ltd. filed a patent infringement action against Hetero USA, Inc. in the District of New Jersey over US12102609B2, covering solriamfetol oral tablets at 75 mg and 150 mg doses. The parties reached a stipulated dismissal without prejudice under Rule 41(a)(1)(A)(ii) after just 155 days — with no costs awarded to either side and the court retaining jurisdiction.
ANDA Infringement Dispute Over Solriamfetol Ends in Stipulated Dismissal
On January 29, 2025, Axsome Malta Ltd. and Axsome Therapeutics, Inc. filed a patent infringement action in the U.S. District Court for the District of New Jersey against Hetero USA, Inc., Hetero Labs Limited Unit-V, and Hetero Labs Ltd. The complaint asserted US12102609B2 in connection with Hetero’s abbreviated new drug application (ANDA) seeking approval for generic solriamfetol oral tablets at 75 mg and 150 mg base equivalents — the same doses marketed by Axsome under the brand Sunosi.
The case closed on July 3, 2025, via a stipulated dismissal under Federal Rule of Civil Procedure 41(a)(1)(A)(ii). All claims, counterclaims, and affirmative defenses asserted by both sides were dismissed without prejudice, and no costs or attorneys’ fees were awarded to any party. The court retained jurisdiction to enforce the agreement and resolve any future disputes relating to the subject matter of the action, which is consistent with an underlying settlement or licensing arrangement.
At 155 days, the resolution is notably swift for ANDA patent litigation, which typically involves a 30-month stay and multi-year proceedings. The parties’ agreement to preserve the court’s jurisdiction suggests the dismissal likely reflects a negotiated commercial resolution rather than a unilateral withdrawal. The public record does not disclose the specific terms — including any license, market entry date, or royalty arrangement — leaving the commercial outcome opaque.
Filing to Dismissed without Prejudice in 155 days
155 days — resolved well before typical ANDA litigation timelines of 2–3 years
Dismissed without prejudice: what the stipulation means for both parties
Rule 41(a)(1)(A)(ii): stipulated dismissal by agreement
Under Federal Rule of Civil Procedure 41(a)(1)(A)(ii), parties may jointly stipulate to dismiss an action. Because the dismissal is without prejudice, Axsome retains the right to refile infringement claims on the same patent if warranted. The court’s retained jurisdiction is a hallmark of a court-supervised settlement rather than a simple withdrawal.
Refiling remains possibleWithout prejudice — not the same as a defendant win
A dismissal without prejudice does not constitute a merits ruling in Hetero’s favour. Axsome’s patent claims survive intact and could be reasserted. A dismissal with prejudice would have barred Axsome from relitigating the same claims — that is not the case here. The public record is silent on whether a licence, consent judgment, or market entry date was agreed privately.
No merits adjudicationAxsome’s patent remains enforceable and unchallenged on the merits
Axsome exits the litigation with US12102609B2 fully intact — no invalidity ruling, no adverse claim construction, and no finding of non-infringement. The without-prejudice dismissal and retained jurisdiction suggest Axsome secured sufficient commercial protections to justify ending the proceeding. The patent’s enforceability against other potential ANDA filers is unaffected.
Patent survives unchallengedHetero exits without a validity win — terms likely include constraints
Hetero did not obtain a ruling of invalidity or non-infringement, which limits the precedential value of the outcome for other generic competitors. The court’s retained jurisdiction signals ongoing obligations. Hetero’s commercial path to market for generic solriamfetol likely depends on terms negotiated privately with Axsome, which are not publicly available.
No precedential validity rulingFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Axsome Malta, Ltd. | Company | Pharmaceutical IP holding company — holder of US12102609B2 covering solriamfetol formulationsSearch in Eureka ↗ |
| Defendant | Hetero USA, Inc. | Company | Generic pharmaceutical manufacturer filing ANDA for solriamfetol 75 mg and 150 mg tabletsSearch in Eureka ↗ |
| Plaintiff counsel | Alexander Lee Callo | 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 | 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 | Saul Ewing LLP | Law Firm | Representing Axsome Malta, Ltd.Search in Eureka ↗ |
| Defendant counsel | Kaan Ekiner | Attorney | Counsel for Hetero USA, Inc.Search in Eureka ↗ |
| Defendant law firm | Cozen O’connor PC | Law Firm | Representing Hetero USA, Inc.Search in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | New Jersey District CourtSearch in Eureka ↗ |
Official order — verbatim text
The stipulation expressly dismisses all claims, counterclaims, and affirmative defenses without prejudice — meaning no party obtained a merits ruling. The phrase ‘without costs or attorneys’ fees to any party’ reflects a clean mutual release of litigation expenses, consistent with a negotiated resolution. Crucially, the court’s retained jurisdiction over disputes relating to the subject matter suggests enforceable obligations were agreed privately, even if undisclosed in the public docket.
US12102609B2 — Solriamfetol Oral Tablet Formulations
US12102609B2 (application number US18/491319) covers solriamfetol oral tablet formulations, a dopamine and norepinephrine reuptake inhibitor approved for excessive daytime sleepiness associated with narcolepsy and obstructive sleep apnea. The patent is held by Axsome Malta Ltd. and sits within the Orange Book listing for Sunosi, Axsome’s branded solriamfetol product. Its assertion in this ANDA context reflects standard Hatch-Waxman enforcement practice.
Solriamfetol occupies a differentiated position in the CNS wakefulness space, and US12102609B2 represents a key formulation-level asset in Axsome’s defensive IP stack. For generic manufacturers targeting the solriamfetol market, this patent — which survived the Hetero challenge without any adverse ruling — constitutes a significant barrier to entry. Competitors contemplating Paragraph IV certifications should assess claim scope carefully before proceeding.
Should your team run an FTO analysis against US12102609B2?
Any company developing or commercialising solriamfetol oral tablet formulations — at 75 mg or 150 mg doses or adjacent strengths — should treat US12102609B2 as an active blocking patent. The Axsome v. Hetero dismissal without prejudice and with court-retained jurisdiction confirms the patent is being actively enforced. R&D teams exploring CNS wakefulness formulations with similar reuptake inhibitor mechanisms should commission a dedicated FTO analysis before advancing to IND or ANDA filing.
PatSnap Eureka’s FTO Search Agent allows IP teams to map claim-level coverage of US12102609B2 against proposed formulation candidates in minutes. Upload your candidate compound profile, and Eureka will identify claim overlaps, prosecution history estoppel points, and design-around opportunities — enabling smarter go/no-go decisions at the formulation stage, well before costly clinical or regulatory investment.
Run a freedom-to-operate analysis on US12102609B2 to assess your product’s exposure
Run FTO in Eureka →Similar ANDA Patent Cases Involving CNS Formulation Patents in D.N.J.
Explore comparable Hatch-Waxman infringement actions involving CNS wakefulness and reuptake inhibitor formulation patents filed in the District of New Jersey.
What this case signals for the solriamfetol and CNS drug IP landscape
A swift stipulated dismissal in an ANDA case typically signals a negotiated resolution — with significant implications for generic entry timing and patent enforcement strategy.
Speed of resolution suggests a pre-litigation or early-stage settlement
At 155 days, this case resolved far faster than the typical ANDA litigation cycle. That pace, combined with the retained jurisdiction clause, is consistent with a licence or consent agreement reached shortly after suit was filed — possibly triggered by Hetero’s ANDA filing and the resulting 30-month stay period.
US12102609B2 remains a live enforcement asset for Axsome
Because the dismissal is without prejudice and carries no invalidity finding, Axsome can assert US12102609B2 against any subsequent ANDA filer for solriamfetol. Competitors in the generic CNS space should treat this patent as an active blocking position until its expiry or a successful IPR challenge.
Axsome v Hetero — key questions answered
The case was dismissed without prejudice by stipulation of the parties under Rule 41(a)(1)(A)(ii) on July 3, 2025, after 155 days. No costs or attorneys’ fees were awarded, and the District of New Jersey retained jurisdiction to enforce any underlying agreement.
The asserted patent is US12102609B2 (application US18/491319), covering solriamfetol oral tablet formulations. The products at issue are solriamfetol oral tablets at 75 mg base equivalent and 150 mg base equivalent, corresponding to the doses in Axsome’s branded product Sunosi.
Not necessarily. A dismissal without prejudice does not grant Hetero a clear path to market. The court’s retained jurisdiction suggests private terms may restrict or schedule any generic launch. Hetero did not obtain an invalidity or non-infringement ruling, so US12102609B2 remains an active barrier.
Yes. Because the dismissal is without prejudice, Axsome retains the right to refile claims under US12102609B2 against Hetero if the underlying agreement is breached or if new grounds for infringement arise. The patent itself is not invalidated or disclaimed by this outcome.
Retained jurisdiction in a stipulated dismissal typically signals the existence of a private settlement or licence agreement with enforceable obligations — such as a scheduled generic launch date or royalty milestones. If either party breaches those terms, the court can be invoked without the need to file a new complaint, providing a faster enforcement mechanism.
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