Novartis v. Alembic: Federal Circuit Splits Decision on Entresto® Patents
Novartis Pharmaceuticals Corporation faced Alembic Pharmaceuticals in a Federal Circuit appeal over four patents protecting Entresto® (sacubitril/valsartan), a blockbuster heart failure therapy. The court issued a split ruling — affirming some claims, reversing others — across a 529-day appellate proceeding that concluded January 10, 2025.
A split Federal Circuit verdict on Entresto®’s patent fortress
Novartis Pharmaceuticals Corporation filed this appeal at the Court of Appeals for the Federal Circuit on July 31, 2023, challenging an underlying district court ruling concerning four patents — US8101659B2, US9388134B2, US8796331B2, and US8877938B2 — that collectively protect Entresto® (sacubitril and valsartan, 24/26 mg, 49/51 mg, and 97/103 mg), a first-in-class angiotensin receptor–neprilysin inhibitor approved for heart failure with reduced ejection fraction.
The Federal Circuit closed the case on January 10, 2025, issuing an order affirmed in part, reversed in part. This split disposition means the lower court’s findings survived appellate scrutiny on certain issues but were overturned on others, leaving neither Novartis nor Alembic with a clean victory. The practical effect depends on which specific patent claims or invalidity/infringement determinations were affirmed versus reversed — details not fully specified in the public docket entry.
The 529-day duration suggests the appeal involved substantive briefing on complex chemical and claim-construction questions, consistent with ANDA-related pharmaceutical litigation at the Federal Circuit. The partial reversal is notable: it signals the district court made at least one legal or factual error material enough to disturb on appeal, while also getting other determinations right. What remains unclear from the public record is the precise allocation of wins and losses across the four asserted patents and whether remand proceedings are required.
Filing to Appeal Granted In Part in 529 days
529-day appeal — above the median for Federal Circuit patent infringement cases
Federal Circuit affirms in part, reverses in part: what the split ruling means
What ‘affirmed in part, reversed in part’ means at the Federal Circuit
A split disposition means the appellate panel found no reversible error in some of the district court’s conclusions — those portions stand — but identified legal or factual error sufficient to overturn other conclusions. The Federal Circuit applies de novo review to claim construction and legal questions, and clear-error review to factual findings. A partial reversal typically signals a meaningful legal disagreement on at least one issue, and may trigger remand for further proceedings below.
Partial reversal on appealNovartis: some patent positions survive, others overturned
For Novartis, the affirmance component preserves its infringement or validity findings on those claims the Federal Circuit left intact — sustaining enforceability of Entresto®’s patent estate to that extent. However, the reversal component is a setback: one or more district court determinations favourable to Novartis were overturned, potentially opening a path for Alembic’s generic entry on those specific claims or patents. The scope of continued protection depends on which of the four patents’ claims survived intact.
Mixed — partial protection maintainedAlembic wins reversal on some issues but faces remaining patent barriers
Alembic secured a partial victory: the reversed portion of the ruling clears one or more obstacles to its ANDA-based generic Entresto® product. This is commercially significant given Entresto®’s multi-billion-dollar revenue base. However, the affirmed portion means Alembic still faces valid, enforceable patent claims it must design around or await expiry of, limiting the scope of any immediate generic launch opportunity that the reversal may have created.
Partial win — launch path still constrainedEntresto® exclusivity landscape shifts but is not dismantled
The split outcome suggests the Entresto® patent portfolio retains meaningful enforceability — the Federal Circuit did not wholesale invalidate or find non-infringement across all four patents. For the broader pharmaceutical sector, a partial reversal in a high-value ANDA case underscores the risk of relying on any single patent claim layer. Generic manufacturers in the sacubitril/valsartan space should monitor remand proceedings and track which specific claims remain in force before finalising launch strategies.
Entresto® exclusivity partially intactFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Novartis Pharmaceuticals Corporation | Company | Novartis Pharmaceuticals Corporation — holder of US8101659B2 and three further Entresto® patentsSearch in Eureka ↗ |
| Defendant | ALEMBIC PHARMACEUTICALS LIMITED | Individual | Alembic Pharmaceuticals Limited and Alembic Pharmaceuticals, Inc. — generic pharmaceutical ANDA filerSearch in Eureka ↗ |
| Co-Defendant | Alembic Pharmaceuticals, Inc. | Company | Search in Eureka ↗ |
| Plaintiff counsel | Christina A. L. Schwarz | Attorney | Counsel for Novartis Pharmaceuticals CorporationSearch in Eureka ↗ |
| Plaintiff counsel | Deanne Maynard | Attorney | Counsel for Novartis Pharmaceuticals CorporationSearch in Eureka ↗ |
| Plaintiff counsel | Nicholas Nick Kallas | Attorney | Counsel for Novartis Pharmaceuticals CorporationSearch in Eureka ↗ |
| Plaintiff counsel | Seth W. Lloyd | Attorney | Counsel for Novartis Pharmaceuticals CorporationSearch in Eureka ↗ |
| Plaintiff law firm | Morrison & Foerster LLP | Law Firm | Representing Novartis Pharmaceuticals CorporationSearch in Eureka ↗ |
| Plaintiff law firm | Venable LLP | Law Firm | Representing Novartis Pharmaceuticals CorporationSearch in Eureka ↗ |
| Defendant counsel | Eve H. Ormerod | Attorney | Counsel for ALEMBIC PHARMACEUTICALS LIMITEDSearch in Eureka ↗ |
| Defendant law firm | Smith, Katzenstein, & Jenkins LLP | Law Firm | Representing ALEMBIC PHARMACEUTICALS LIMITEDSearch in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | Court of Appeals for the Federal CircuitSearch in Eureka ↗ |
Official order — verbatim text
The Federal Circuit’s order — ‘AFFIRMED IN PART, REVERSED IN PART’ — reflects a considered application of differing standards of review across distinct legal and factual questions arising from the district court record. Claim construction issues, reviewed de novo, are the most common basis for reversal in pharmaceutical patent appeals; factual questions receive clear-error deference. That the court reversed on at least one dimension while affirming others suggests the district court correctly resolved some but not all disputes across the four Entresto® patents. Neither party obtained a complete appellate vindication.
US8101659B2 — sacubitril/valsartan heart failure compound patents
The four asserted patents — US8101659B2, US9388134B2, US8796331B2, and US8877938B2 — span multiple application families and collectively protect various aspects of sacubitril and valsartan as used in Entresto®, including compound compositions, formulations, and potentially method-of-use or process claims. The application dates range across filings in the mid-2000s through early 2010s, reflecting a layered prosecution strategy designed to extend exclusivity across multiple claim types. Entresto® received FDA approval in 2015 and represents a first-in-class angiotensin receptor–neprilysin inhibitor (ARNi) for heart failure with reduced ejection fraction.
Strategically, this four-patent portfolio exemplifies the originator practice of surrounding a breakthrough molecule with overlapping claim layers to deter and delay generic entry. Each patent represents a distinct barrier a generic filer must clear — whether through invalidity challenges, non-infringement arguments, or design-around. Given Entresto®’s multi-billion-dollar annual revenue, the commercial stakes attached to each individual claim are substantial. The partial Federal Circuit reversal suggests at least one layer of this fortress has been weakened, making portfolio monitoring by competitors and licensing analysts critically important.
Should you run an FTO against the Entresto® patent family?
Any company developing sacubitril/valsartan-based formulations, ARNI combination therapies, or generic equivalents to Entresto® should treat this Federal Circuit ruling as a trigger for an updated freedom-to-operate assessment. The partial reversal changes the enforceability landscape of at least one of the four asserted patents, but the affirmed claims remain live hazards. Product teams and regulatory affairs groups advancing ANDA or 505(b)(2) applications in this space cannot rely on pre-appeal FTO analyses.
PatSnap Eureka’s FTO Search Agent enables targeted claim-by-claim mapping against the Entresto® patent family — US8101659B2, US9388134B2, US8796331B2, and US8877938B2 — factoring in the current post-appeal claim scope. Eureka can surface related continuation applications, track litigation history across all family members, and flag any downstream prosecution activity that could affect the enforceability of surviving claims, giving IP and R&D teams a current-state risk picture rather than a static snapshot.
Run a freedom-to-operate analysis on US8101659B2 to assess your product’s exposure
Run FTO in Eureka →Similar Federal Circuit pharmaceutical patent appeals: ANDA & ARNi cases
Explore Federal Circuit appeals involving ANDA-challenged pharmaceutical patents, particularly combination cardiovascular therapies, that share procedural and technical characteristics with Novartis v. Alembic.
What this case signals for the pharmaceutical patent IP landscape
A Federal Circuit split on a four-patent ANDA case has direct implications for Entresto® generic timelines and originator enforcement strategy.
Multi-patent stacking does not guarantee full appellate survival
Novartis asserted four patents across different application lineages. The partial reversal confirms that even a dense patent portfolio can have individual weak points. IP teams protecting blockbuster pharmaceutical products should pressure-test each patent independently for claim-construction and obviousness risk before relying on portfolio breadth as a litigation strategy.
Generic entrants should parse which specific claims were reversed before planning launch
A partial reversal creates a fragmented patent landscape. Alembic — and any other ANDA filer tracking this case — must determine precisely which claims were overturned versus affirmed. Launching against a patent the Federal Circuit left intact would still constitute infringement. Careful FTO analysis against the remaining affirmed claims is essential before any commercial action.
Novartis v ALEMBIC — key questions answered
The Federal Circuit issued an ‘affirmed in part, reversed in part’ ruling on January 10, 2025 in case 23-2220. This means the court upheld some of the district court’s findings concerning the four Entresto® patents but overturned others, resulting in a split outcome for both Novartis and Alembic. The precise allocation across the four patents is not fully detailed in the public docket entry.
Novartis asserted four patents: US8101659B2, US9388134B2, US8796331B2, and US8877938B2. These patents span different application families and cover various aspects of the sacubitril and valsartan combination used in Entresto® (24/26 mg, 49/51 mg, and 97/103 mg dosage forms) for the treatment of heart failure.
The partial reversal suggests Alembic cleared some patent barriers at the Federal Circuit level, potentially opening a path to generic entry on those specific claims or patents that were reversed. However, the affirmed portion means at least some Novartis patent claims remain enforceable, meaning Alembic cannot launch without further risk analysis against the surviving claims. A detailed FTO review of the affirmed claims is essential before any commercial decision.
The appeal was filed on July 31, 2023 and closed on January 10, 2025, a duration of 529 days. This is consistent with substantive Federal Circuit briefing schedules for complex pharmaceutical patent cases involving multiple patents and ANDA-related infringement questions, though it is above the median for straightforward appeals.
Novartis was represented by Morrison & Foerster LLP and Venable LLP, with counsel including Deanne Maynard, Nicholas Kallas, Christina Schwarz, and Seth Lloyd. Alembic was represented by Smith, Katzenstein & Jenkins LLP, with Eve H. Ormerod as lead counsel of record.
PatSnap Eureka searches patents and litigation data to answer instantly.