MSN Pharmaceuticals v. Novartis AG: Federal Circuit Appeal Voluntarily Dismissed in 43 Days
MSN Pharmaceuticals and Novartis AG jointly agreed to dismiss a Federal Circuit infringement appeal covering four patents on sacubitril/valsartan compounds and related treatment methods. The case closed in just 43 days under Fed. R. App. P. 42(b), with each side bearing its own costs — leaving the underlying patent landscape unresolved on the merits.
A swift mutual exit from a high-stakes sacubitril/valsartan appeal
MSN Pharmaceuticals, Inc. filed this appeal at the Court of Appeals for the Federal Circuit on 1 May 2025, challenging aspects of an infringement dispute with Novartis AG over four US patents covering compounds containing sacubitril/valsartan moieties and associated pharmaceutical compositions and methods of treatment. The patents at issue — US8101659B2, US9388134B2, US8796331B2, and US8877938B2 — collectively protect the chemical architecture and therapeutic use of the active ingredients in Novartis’s blockbuster heart failure drug Entresto.
The appeal was terminated on 13 June 2025 after just 43 days, when both parties agreed to dismiss the proceeding under Fed. R. App. P. 42(b). The court ordered dismissal on those agreed terms, with each side bearing its own costs. Because the dismissal was voluntary and agreed, the Federal Circuit issued no substantive ruling on the merits — the patents were neither validated nor invalidated at this appellate stage, and no infringement finding was entered or overturned.
A 43-day lifecycle before full briefing is typically consistent with a negotiated resolution reached soon after the appeal was docketed — whether a broader settlement, a licensing arrangement, or a strategic withdrawal. The public record is silent on the specific commercial terms, if any, that accompanied this dismissal. What remains unknown is whether MSN retains any pathway to market for its proposed generic or follow-on formulation, and whether parallel proceedings in other forums continue to define the competitive boundaries of Novartis’s sacubitril/valsartan patent estate.
Filing to Voluntary dismissal in 43 days
43 days — resolved before full appellate briefing typically completes
Voluntarily dismissed at the Federal Circuit: what the agreed exit means for both parties
Fed. R. App. P. 42(b): agreed voluntary dismissal at appeal stage
Rule 42(b) allows parties to a Federal Circuit appeal to stipulate to dismissal without a merits ruling. Unlike a district court voluntary dismissal under Rule 41, a Rule 42(b) dismissal closes the appellate proceeding entirely. No judgment on infringement or validity is entered, and no precedential ruling is created. The underlying lower-court record remains as-is, unaffected by this dismissal.
No merits adjudicationThe public record is silent on prejudice terms
Fed. R. App. P. 42(b) dismissals do not automatically carry ‘with prejudice’ or ‘without prejudice’ designations in the same way district court Rule 41 dismissals do. The court order here specifies only that the proceeding is dismissed and costs are split. Whether MSN is barred from re-raising the same appellate arguments in future proceedings is not apparent from the public docket — the operative terms of any underlying agreement, if one exists, are not disclosed.
Prejudice terms undisclosedAppeal withdrawn: MSN’s challenge ends without a favourable ruling
By agreeing to dismiss, MSN Pharmaceuticals obtains no appellate ruling in its favour. Any invalidity or non-infringement arguments it raised at the lower level are not vindicated here. Whether MSN secured commercial concessions — such as a licensing agreement or a delayed market entry date — in exchange for withdrawal is not reflected in the public record. The dismissal leaves Novartis’s patent estate intact at this level.
No ruling in appellant’s favourPatent estate survives appeal without judicial scrutiny
Novartis AG exits the Federal Circuit appeal without any of its four sacubitril/valsartan patents being adjudicated on validity or infringement grounds at the appellate level. This preserves the strength and enforceability of the patents, at least formally. However, the absence of a merits affirmance means the patents have not been judicially reinforced — future challengers face the same legal landscape that existed before this appeal was filed.
Patents intact, not judicially strengthenedFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Msn Pharmaceuticals, Inc. | Company | Generic pharmaceutical developer — appellant asserting challenge to Novartis sacubitril/valsartan patentsSearch in Eureka ↗ |
| Defendant | Novartis, AG | Company | Novartis AG — multinational pharmaceutical company, holder of the Entresto (sacubitril/valsartan) patent estateSearch in Eureka ↗ |
| Plaintiff counsel | Deanne M. Mazzochi | Attorney | Counsel for Msn Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Kevin E. Warner | Attorney | Counsel for Msn Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Richard Charles Weinblatt | Attorney | Counsel for Msn Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Richard Juang | Attorney | Counsel for Msn Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Ronald M. Daignault | Attorney | Counsel for Msn Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | William A. Rakoczy | Attorney | Counsel for Msn Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Daignault Iyer LLP | Law Firm | Representing Msn Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Rakoczy, Molino, Mazzochi, Siwik LLP | Law Firm | Representing Msn Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Stamoulis & Weinblatt LLC | Law Firm | Representing Msn Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Christina A. L. Schwarz | Attorney | Counsel for Novartis, AGSearch in Eureka ↗ |
| Defendant counsel | Deanne Maynard | Attorney | Counsel for Novartis, AGSearch in Eureka ↗ |
| Defendant counsel | Nicholas Nick Kallas | Attorney | Counsel for Novartis, AGSearch in Eureka ↗ |
| Defendant counsel | Seth W. Lloyd | Attorney | Counsel for Novartis, AGSearch in Eureka ↗ |
| Defendant counsel | Zach ZhenHe Tan | Attorney | Counsel for Novartis, AGSearch in Eureka ↗ |
| Defendant law firm | Morrison & Foerster LLP | Law Firm | Representing Novartis, AGSearch in Eureka ↗ |
| Defendant law firm | Venable LLP | Law Firm | Representing Novartis, AGSearch in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | Court of Appeals for the Federal CircuitSearch in Eureka ↗ |
Official order — verbatim text
The court’s order reflects a purely procedural disposition: both parties agreed to dismiss under Fed. R. App. P. 42(b), and the Federal Circuit simply recorded that agreement. The order is non-precedential and contains no analysis of claim construction, validity, or infringement. The cost-split — ‘each side shall bear their own costs’ — is a neutral commercial term that neither signals litigation strength nor weakness. In agreed Federal Circuit dismissals, the operative commercial terms typically reside in a confidential settlement or licensing agreement not reflected in the docket.
US8101659B2 and three further patents — sacubitril/valsartan compound and method estate
The four patents at issue — US8101659B2, US9388134B2, US8796331B2, and US8877938B2 — protect the chemical composition and therapeutic use of the sacubitril/valsartan complex, commercially known as Entresto. The compound combines an angiotensin receptor blocker (valsartan) with a neprilysin inhibitor (sacubitril) in a supramolecular sodium salt complex. Application dates span 2007 through 2014, reflecting iterative patent filings across the compound’s development lifecycle from initial synthesis to formulated pharmaceutical compositions.
Entresto generated approximately $6 billion in global net sales in 2024, making this patent estate among the most commercially significant in cardiovascular medicine. The layered structure of four patents — covering the compound itself, specific moieties, formulations, and methods of treatment — creates a multi-barrier enforcement landscape for generic entrants. Any company pursuing an ANDA or 505(b)(2) application for a sacubitril/valsartan product must contend with each patent independently, raising the cost and complexity of market entry challenges.
Should your team run an FTO against the Novartis sacubitril/valsartan patent estate?
Any pharmaceutical company or CDMO developing a sacubitril/valsartan formulation, salt form, or method-of-treatment product should treat this four-patent stack as a material FTO risk. The patents cover not only the core compound but also specific moieties and therapeutic methods — meaning even reformulated or combination products may fall within claim scope. Generic developers, 505(b)(2) applicants, and biosimilar-adjacent cardiovascular drug developers should assess each patent’s claim boundaries before advancing to IND or ANDA filing stages.
PatSnap Eureka’s FTO Search Agent allows IP teams to map claim language across all four patents simultaneously, identify published prior art that may support design-around strategies, and flag co-pending applications in Novartis’s sacubitril/valsartan filing family. Eureka’s landscape analysis can surface related patents that may extend exclusivity beyond the four asserted here — giving R&D and legal teams a complete picture of the freedom-to-operate perimeter before committing development resources.
Run a freedom-to-operate analysis on US8101659B2 to assess your product’s exposure
Run FTO in Eureka →Similar Federal Circuit pharmaceutical compound patent appeals
Cases involving multi-patent sacubitril/valsartan or cardiovascular compound appeals at the Federal Circuit, including Hatch-Waxman and ANDA-related infringement proceedings.
What this case signals for the sacubitril/valsartan IP landscape
A rapid agreed dismissal in a multi-patent Federal Circuit appeal over a blockbuster heart failure drug typically signals significant commercial stakes beyond the courtroom.
Early dismissal often precedes a broader commercial agreement
When a Federal Circuit appeal involving blockbuster pharmaceutical patents closes in 43 days — before substantive briefing completes — it is consistent with parties reaching a negotiated resolution. Generic entrants and branded pharmaceutical companies frequently settle at the appellate stage through licensing or delayed-entry arrangements. Monitoring ANDA-related filings and any subsequent MSN product launches may reveal the operative terms.
Four-patent stack signals a layered enforcement strategy by Novartis
Novartis asserted four US patents with application dates spanning 2007 to 2014, collectively covering the compound structure, formulations, and treatment methods of sacubitril/valsartan. This layered patent portfolio approach is characteristic of branded pharma’s evergreening strategy — each additional patent extends the window during which generics must navigate or challenge the estate. The dismissal does not narrow that stack.
Msn v Novartis — key questions answered
The Federal Circuit appeal was voluntarily dismissed by agreement of the parties under Fed. R. App. P. 42(b) on 13 June 2025, just 43 days after filing. No merits ruling on infringement or validity was issued. Each side bears its own costs. The case involved four patents covering sacubitril/valsartan compounds and treatment methods.
Four US patents were at issue: US8101659B2, US9388134B2, US8796331B2, and US8877938B2. These patents collectively cover compounds containing sacubitril and valsartan moieties, related biphenyl-containing pharmaceutical compositions, and methods of treatment — the core IP underpinning Novartis’s Entresto heart failure drug.
Not definitively. A Rule 42(b) voluntary dismissal by agreement carries no merits adjudication. The Federal Circuit issued no ruling on validity or infringement. Novartis’s patents remain intact and unchallenged at the appellate level from this proceeding, but they have not been judicially affirmed in strength — future challengers face the same legal landscape as before.
In Federal Circuit practice, a cost-split order means neither party recovers appellate filing fees or taxable costs from the other. It is a commercially neutral term that does not indicate which party was in a stronger legal position. It is commonly seen in agreed dismissals and does not preclude a separate confidential settlement agreement governing other financial terms.
The public record does not specify whether the dismissal was with or without prejudice to further proceedings. Fed. R. App. P. 42(b) dismissals do not automatically bar future challenges. Whether MSN is contractually restricted from re-litigating these patents depends on any private agreement reached between the parties, which has not been disclosed on the public docket.
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