MSN Pharmaceuticals v. Novartis AG — Federal Circuit Appeal Voluntarily Dismissed (43 Days)
MSN Pharmaceuticals filed a Federal Circuit appeal against Novartis AG over four patents covering sacubitril/valsartan compound moieties and pharmaceutical treatment methods. The parties jointly agreed to dismiss the appeal under Fed. R. App. P. 42(b) within 43 days of filing, with each side bearing its own costs — leaving no merits ruling on record.
A short-lived Federal Circuit skirmish over heart failure drug patents
MSN Pharmaceuticals, Inc. initiated this Federal Circuit appeal on 1 May 2025, challenging Novartis AG over four US patents — US8101659B2, US9388134B2, US8796331B2, and US8877938B2 — covering compounds containing the sacubitril and valsartan moieties central to Novartis’s blockbuster heart failure drug Entresto, as well as related pharmaceutical compositions and treatment methods. The appeal followed an underlying infringement action, consistent with ANDA-related generic pharmaceutical litigation patterns common in this space.
The proceeding was dismissed on 13 June 2025 — just 43 days after filing — pursuant to Fed. R. App. P. 42(b), which governs voluntary dismissal of federal appeals by stipulation of the parties. The dismissal order records that the parties ‘having so agreed’ consented to termination, with each side bearing its own costs. The public record does not specify whether the dismissal was with or without prejudice, a distinction that carries material consequence for MSN’s ability to relitigate the same claims.
A 43-day appellate lifespan is notably brief and typically suggests that the parties reached a confidential resolution — whether a licensing arrangement, settlement, or strategic withdrawal — shortly after the appeal was docketed. What drove the rapid resolution is not disclosed in the public record. The absence of a merits ruling means the four patents remain formally unchallenged at the appellate level, preserving Novartis’s enforcement position. Whether MSN retains the right to reassert its challenge depends on the undisclosed terms of any underlying agreement.
Filing to Voluntary dismissal in 43 days
43 days from filing to dismissal — a notably short appellate lifespan suggesting rapid settlement or strategic withdrawal
Voluntarily dismissed: what the agreed termination means for both parties
Fed. R. App. P. 42(b): voluntary dismissal by stipulation
Fed. R. App. P. 42(b) allows an appellate proceeding to be dismissed when the parties jointly agree. No court merits analysis is conducted; the appeal simply ceases. This mechanism is commonly invoked when parties settle or when the appellant (here, MSN) elects to withdraw. Crucially, the public docket does not record whether this dismissal was with or without prejudice — a distinction that determines whether MSN can renew its challenge.
No merits ruling issuedThe public record is silent on prejudice — and it matters
A dismissal with prejudice bars the dismissing party from re-filing the same claims; without prejudice preserves that right. The order here states only that the proceeding is ‘DISMISSED under Fed. R. App. P. 42(b)’ — no prejudice designation is recorded. This ambiguity is legally significant: practitioners advising MSN or Novartis on future strategy cannot assume either outcome from the face of the public docket alone.
Prejudice status undisclosedNovartis patents survive the appeal unchallenged on the merits
With no appellate merits ruling, all four patents — US8101659B2, US9388134B2, US8796331B2, and US8877938B2 — remain intact and unaffirmed by the Federal Circuit. Novartis retains its enforcement position but without the added weight of an appellate validity endorsement. The cost-neutral outcome (each side bears own costs) suggests the resolution was agreed rather than conceded.
Patents intact, no appellate endorsementMSN exits the appeal without a ruling — strategic flexibility preserved or foreclosed
MSN Pharmaceuticals’ voluntary withdrawal forecloses an appellate merits win at this stage. Whether MSN retains any path to market for its sacubitril/valsartan generic — through a licensing deal, a future ANDA challenge, or IPR — depends on the undisclosed terms driving this dismissal. The 43-day timeline suggests a negotiated resolution rather than pure litigation fatigue, but the public record does not confirm this.
Future challenge path unclearFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Msn Pharmaceuticals, Inc. | Company | Generic pharmaceutical company — challenger of US8101659B2 and three related sacubitril/valsartan patentsSearch in Eureka ↗ |
| Defendant | Novartis, AG | Company | Novartis AG — multinational pharmaceutical company and holder of the Entresto (sacubitril/valsartan) patent portfolioSearch 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 dismissal order’s language — ‘The parties having so agreed’ — confirms this was a bilateral, consensual exit under Fed. R. App. P. 42(b), not a unilateral withdrawal or court-ordered termination. No substantive legal standard was applied; no claim construction, validity analysis, or infringement finding is embedded in the order. The cost-neutrality provision is consistent with a negotiated resolution. Because no merits ruling was issued, neither party can cite this proceeding as precedent, and the enforceability of all four patents is unchanged by this disposition.
US8101659B2 — sacubitril/valsartan compound moieties for heart failure treatment
The four patents at issue — US8101659B2, US9388134B2, US8796331B2, and US8877938B2 — protect compounds containing the S-N-valeryl-N-{[2′-(1H-tetrazole-5-yl)-biphenyl-4-yl]-methyl}-valine and (2R,4S)-5-biphenyl-4-yl-4-(3-carboxy-propionylamino)-2-methyl-pentanoic acid ethyl ester moieties — the pharmacologically active components of sacubitril/valsartan — alongside pharmaceutical compositions and methods of cardiovascular treatment. These patents underpin Novartis’s Entresto franchise, which combines a neprilysin inhibitor (sacubitril) with an angiotensin receptor blocker (valsartan) for heart failure with reduced ejection fraction.
Entresto is one of the highest-revenue cardiovascular drugs globally, and this patent cluster forms a critical barrier to generic entry. The breadth of protection — spanning compound structure, formulation, and method of treatment — creates a multi-layered enforcement wall that generic challengers such as MSN must navigate across all four patents simultaneously. Any generic manufacturer seeking to market a sacubitril/valsartan product in the US must conduct a thorough FTO assessment against this portfolio, as Novartis has demonstrated willingness to assert these patents aggressively in district court and at the appellate level.
Should you run an FTO against US8101659B2 and the Entresto patent cluster?
Any pharmaceutical company or CMO developing, manufacturing, or seeking ANDA approval for a sacubitril/valsartan generic product should treat US8101659B2, US9388134B2, US8796331B2, and US8877938B2 as high-priority FTO targets. The compound, formulation, and method claims collectively cover multiple routes to market. Even partial design-around strategies require claim-level analysis across all four patents to identify freedom or exposure.
PatSnap Eureka’s FTO Search Agent allows R&D and IP teams to map each of the four Entresto-related patents against a proposed generic compound structure or formulation, identify claim-by-claim risk, and surface prior art relevant to validity challenges. Eureka can also track downstream Novartis continuation filings that may extend protection beyond the current patent expiry dates — critical for modelling a generic entry timeline with confidence.
Run a freedom-to-operate analysis on US8101659B2 to assess your product’s exposure
Run FTO in Eureka →Similar Federal Circuit appeals in sacubitril/valsartan and ANDA pharmaceutical patent litigation
Related Federal Circuit appeals and district court ANDA cases involving the Entresto sacubitril/valsartan patent portfolio and pharmaceutical compound infringement actions.
What this case signals for the sacubitril/valsartan generic IP landscape
A 43-day voluntary Federal Circuit dismissal over Entresto-related patents is a commercially significant signal for generic pharma strategy.
Rapid voluntary dismissals at the Federal Circuit often mask deal terms
When both parties agree to dismiss a Federal Circuit appeal within weeks of filing — with each side bearing its own costs — it is consistent with a confidential settlement or licensing agreement. Generic pharma practitioners should treat this outcome as a potential market-entry signal rather than a straightforward withdrawal by MSN.
Novartis’s four-patent cluster over sacubitril/valsartan moieties remains judicially untested at appeal
None of the four patents (US8101659B2, US9388134B2, US8796331B2, US8877938B2) received a merits ruling from the Federal Circuit in this proceeding. For other generic entrants eyeing the Entresto space, this means no appellate precedent has been set that weakens — or strengthens — these claims.
Msn v Novartis — key questions answered
The Federal Circuit dismissed the appeal under Fed. R. App. P. 42(b) by mutual agreement of the parties. No merits ruling was issued. All four Novartis patents — US8101659B2, US9388134B2, US8796331B2, and US8877938B2 — remain enforceable and unchallenged at the appellate level. The dismissal neither validates nor invalidates any patent claim.
The public dismissal order does not specify whether the dismissal was with or without prejudice. The order states only that the proceeding is ‘DISMISSED under Fed. R. App. P. 42(b).’ The prejudice status — which determines whether MSN may refile a similar challenge — is not ascertainable from the public docket.
Four Novartis patents were at issue: US8101659B2, US9388134B2, US8796331B2, and US8877938B2. These patents cover compounds containing sacubitril and valsartan moieties, pharmaceutical compositions, and methods of cardiovascular treatment — collectively forming the core IP underlying the Entresto drug franchise.
The 43-day duration between filing (1 May 2025) and dismissal (13 June 2025) is notably brief for a Federal Circuit appeal. This timeline is consistent with the parties having reached a confidential resolution — potentially a licensing arrangement, settlement, or co-existence agreement — shortly after docketing. The public record does not disclose the underlying reasons for the rapid dismissal.
The cost-neutral outcome — each side bears its own costs — suggests neither party extracted a dominant litigation advantage in the lead-up to dismissal. In cases where one party clearly prevails on leverage, cost-shifting is more common. The symmetric allocation is consistent with a negotiated resolution rather than a concession by either side, though the public record does not confirm any underlying agreement.
PatSnap Eureka searches patents and litigation data to answer instantly.