Onyx Therapeutics v. Somerset Therapeutics: Infringement Action Ends With Prejudice
Onyx Therapeutics filed suit in the Delaware District Court against Somerset Therapeutics, asserting US7737112B2 covering enzyme inhibitor compositions. The case closed 162 days after filing via a stipulated dismissal with prejudice — a resolution that permanently bars Onyx from re-filing the same claims against Somerset.
A stipulated exit in Delaware: proteasome IP dispute ends permanently
On April 24, 2025, Onyx Therapeutics, Inc. initiated patent infringement proceedings against Somerset Therapeutics, LLC in the United States District Court for the District of Delaware, assigned to Judge Gregory B. Williams. The complaint centred on US7737112B2, a patent directed to compositions for enzyme inhibition — technology that falls within the proteasome inhibitor pharmaceutical space, a class of compounds with established clinical applications in oncology.
The case concluded on October 3, 2025, via a Stipulation of Dismissal filed by Onyx Therapeutics, with the court recording the basis of termination as dismissed with prejudice. A dismissal with prejudice carries a specific and consequential legal meaning: Onyx has permanently relinquished its right to bring these same patent claims against Somerset in federal court. The stipulated nature of the filing suggests both parties agreed to the terms of resolution, which is consistent with an out-of-court settlement, licensing arrangement, or commercial agreement — though no financial terms are publicly disclosed.
The 162-day duration is notably compact for a Delaware patent case, where dockets frequently run to multi-year timelines before resolution. This compressed window suggests the parties either entered litigation with settlement in mind, reached agreement shortly after initial discovery, or resolved the underlying commercial dispute without requiring the court to adjudicate the merits. The absence of defendant counsel on the public record is also notable, potentially suggesting Somerset engaged counsel not yet reflected in available filings, or that the matter was resolved before full litigation posture was established.
Filing to Dismissed with Prejudice in 162 days
162 days — faster than the median Delaware patent case, suggesting early resolution
Dismissed with prejudice: what the stipulated exit means for both parties
Stipulated dismissal with prejudice closes the docket permanently
A dismissal with prejudice filed by stipulation means both parties consented to end the litigation on terms that permanently bar re-filing of the same claims. Unlike a voluntary dismissal without prejudice — which preserves the right to sue again — this disposition is final on the merits as a matter of res judicata. The court retains no further jurisdiction over the underlying patent dispute between these two parties.
Permanent bar on re-filingOnyx forfeits the right to re-assert US7737112 against Somerset
By stipulating to dismissal with prejudice, Onyx Therapeutics has permanently closed the door on enforcing US7737112B2 against Somerset Therapeutics in this forum. This is a meaningful concession — unless the parties reached a licensing or settlement agreement that renders further litigation unnecessary. The public record does not disclose financial terms, so whether Onyx received commercial consideration in exchange remains unknown.
Rights traded or waivedSomerset achieves finality — no merits finding against it
Somerset Therapeutics exits the case without any court finding of infringement, validity, or damages. The dismissal with prejudice provides Somerset with strong preclusion protection against Onyx re-litigating these specific patent claims. If a commercial agreement underlies the dismissal, Somerset may also have secured ongoing rights to practise the patented technology — though this cannot be confirmed from the public docket alone.
No infringement findingEarly exit signals commercial resolution in a competitive pharma niche
The rapid 162-day lifecycle and stipulated with-prejudice dismissal is a pattern commonly associated with settlement or licensing resolution in pharmaceutical patent disputes. For competitors in the proteasome inhibitor and enzyme inhibition composition space, this case is a reminder that US7737112B2 remains an active enforcement asset for Onyx — even where individual disputes resolve quickly. Third parties commercialising related compositions should conduct FTO analysis against this patent.
Patent remains enforceableFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Onyx Therapeutics, Inc. | Company | Pharmaceutical IP holder — holder of US7737112B2, proteasome inhibitor compositionsSearch in Eureka ↗ |
| Defendant | Somerset Therapeutics, LLC | Company | Somerset Therapeutics, LLC — pharmaceutical company alleged to infringe enzyme inhibitor patentSearch in Eureka ↗ |
| Plaintiff counsel | Cameron Paul Clark | Attorney | Counsel for Onyx Therapeutics, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Jeremy A. Tigan | Attorney | Counsel for Onyx Therapeutics, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Megan Elizabeth Dellinger | Attorney | Counsel for Onyx Therapeutics, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Morris, Nichols, Arsht & Tunnell LLP | Law Firm | Representing Onyx Therapeutics, Inc.Search in Eureka ↗ |
| Presiding judge | Judge Gregory B. Williams | Judge | Delaware District CourtSearch in Eureka ↗ |
Official order — verbatim text
The Stipulation of Dismissal filed by Onyx Therapeutics and recorded as dismissed with prejudice reflects a consensual, final resolution. The phrasing indicates both parties agreed to terminate proceedings — the court made no finding on infringement, validity, or damages. The with-prejudice designation operates as a full adjudication on the merits for preclusion purposes, meaning Onyx cannot re-file these specific claims against Somerset. The absence of any publicly recorded fee award is typical in stipulated pharmaceutical patent resolutions where commercial terms are kept confidential.
US7737112B2 — Enzyme inhibitor composition, proteasome-targeting pharmaceutical
US7737112B2, filed under application number US11/299265, protects compositions directed to enzyme inhibition — a category that encompasses proteasome inhibitor compounds with well-established relevance in oncology therapeutics. The patent’s claims define specific composition structures designed to interfere with proteasome enzyme activity, which is a validated mechanism in the treatment of haematological malignancies. The patent has been granted and remains in force as an enforceable asset in Onyx’s portfolio.
Proteasome inhibitors represent a commercially significant pharmaceutical class, with multiple approved drugs — including bortezomib and carfilzomib — generating substantial revenues. US7737112B2 sits in a competitive IP landscape where composition-of-matter claims carry significant defensive and offensive value. For generic pharmaceutical developers, specialty pharma companies, and biotech firms working on enzyme inhibition platforms, this patent represents a non-trivial clearance hurdle. Onyx’s demonstrated willingness to enforce it in Delaware adds commercial urgency to any FTO assessment in this space.
Should your product be cleared against US7737112B2?
Any R&D team or product organisation developing enzyme inhibitor compositions — particularly those targeting proteasome pathways for oncology indications — should conduct a formal freedom-to-operate analysis against US7737112B2. The fact that Onyx filed infringement proceedings against Somerset in 2025 confirms that this patent is actively monitored and enforced. Generic manufacturers, biosimilar developers, and specialty pharma companies entering the proteasome inhibitor space are especially exposed.
PatSnap Eureka’s FTO Search Agent can map your compound’s structural and functional features against the claim scope of US7737112B2, identify prior art that may affect validity, and flag related Onyx patents in the enzyme inhibition family. Eureka’s claim-level analysis helps R&D and legal teams prioritise clearance risk before committing to development timelines — reducing costly late-stage surprises in pharmaceutical product development.
Run a freedom-to-operate analysis on US7737112B2 to assess your product’s exposure
Run FTO in Eureka →Similar proteasome inhibitor patent disputes in Delaware District Court
Related enzyme inhibitor and proteasome pharmaceutical patent cases filed in the District of Delaware, showing comparable enforcement and dismissal patterns.
What this case signals for the proteasome inhibitor IP landscape
A swift, with-prejudice dismissal in Delaware rarely means the dispute simply disappeared — it typically signals a commercial resolution.
US7737112B2 remains live and has demonstrated enforcement intent
Onyx’s willingness to file suit and see it through to a with-prejudice dismissal confirms active enforcement of US7737112B2. Any party commercialising enzyme inhibitor compositions — particularly in the proteasome inhibitor class — should treat this patent as a live enforcement risk and conduct thorough FTO analysis before market entry.
Delaware remains the venue of choice for pharma patent enforcement
Filing in the District of Delaware before Judge Gregory B. Williams is consistent with pharmaceutical patentee strategy. Delaware’s experienced patent judiciary and predictable docket management make it a preferred forum. Companies defending against pharma patent suits in Delaware should engage specialist local counsel early — as this case shows, matters can move quickly.
Onyx v Somerset — key questions answered
Dismissed with prejudice means Onyx Therapeutics permanently relinquished its right to bring the same patent infringement claims under US7737112B2 against Somerset Therapeutics. The dismissal was filed by stipulation, indicating both parties agreed to the resolution. No court finding on infringement or invalidity was made.
US7737112B2 is a US patent covering compositions for enzyme inhibition, specifically directed to proteasome-targeting pharmaceutical compounds. Filed under application US11/299265, it is held by Onyx Therapeutics and covers composition-of-matter claims relevant to the oncology therapeutic space, particularly in haematological malignancy treatment.
The 162-day duration is notably short for Delaware patent litigation, which typically runs considerably longer before resolution. This compressed timeline is consistent with the parties reaching a commercial settlement, licensing agreement, or product withdrawal early in the proceeding. The public record does not disclose the specific commercial terms underlying the dismissal.
No. A dismissal with prejudice operates as a final adjudication on the merits for preclusion purposes. Onyx Therapeutics cannot re-file these specific claims against Somerset Therapeutics based on US7737112B2. However, Onyx retains the right to enforce the patent against other parties and in respect of different infringing acts.
No. The dismissal was procedural and consensual — the court made no finding on the validity or enforceability of US7737112B2. The patent remains in force and Onyx retains full rights to assert it against third parties. Companies operating in the enzyme inhibitor composition space should not treat this dismissal as clearing the patent from FTO analysis.
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