Details for Patent: 8,436,180

Which drugs does patent 8,436,180 protect, and when does it expire?

Patent 8,436,180 protects KERENDIA and is included in one NDA.

This patent has sixty-four patent family members in forty-eight countries.

Summary for Patent: 8,436,180

Title:	Substituted-4-aryl-1,4-dihydro-1,6-naphthyridinamides and use thereof
Abstract:	The present application relates to novel substituted 4-aryl-1,4-dihydro-1,6-naphthyridine-3-carboxamides, a process for their preparation, their use for the treatment and/or prophylaxis of diseases, and their use for the manufacture of medicaments for the treatment and/or prophylaxis of diseases, especially cardiovascular disorders.
Inventor(s):	Lars Bärfacker, Peter Kolkhof, Karl-Heinz Schlemmer, Rolf Grosser, Adam Nitsche, Martina Klein, Klaus Münter, Barbara Albrecht-Küpper, Elke Hartmann
Assignee:	Bayer Intellectual Property GmbH
Application Number:	US12/526,951
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 8,436,180
Patent Claim Types: see list of patent claims	Use; Composition; Process;

US Patent 8,436,180: Scope, Claims, Expiration, and Finerenone Patent Landscape

US Patent 8,436,180 is a Bayer patent covering a broad class of substituted heteroaromatic carboxamides, including the nonsteroidal mineralocorticoid receptor antagonist finerenone, marketed as Kerendia. Its strongest commercial relevance is the claimed compound genus, specific exemplified compounds, manufacturing process, pharmaceutical compositions, combination therapy, and cardiovascular and renal treatment uses. The patent issued May 7, 2013, from a family with a November 24, 2006 priority date. The Orange Book-listed patent term for Kerendia identifies November 24, 2026 as the key expiration date, subject to any applicable patent-term adjustment or regulatory exclusivity recorded by FDA.[1-4]

What drug does US Patent 8,436,180 protect?

US 8,436,180 protects finerenone and related compounds within a substituted heteroaromatic amide genus.

Finerenone is a selective, nonsteroidal mineralocorticoid receptor antagonist developed by Bayer. FDA approved Kerendia on July 9, 2021, to reduce the risk of sustained estimated glomerular filtration rate decline, end-stage kidney disease, cardiovascular death, nonfatal myocardial infarction, and hospitalization for heart failure in adults with chronic kidney disease associated with type 2 diabetes.[5]

The patent's claimed pharmacology is directed primarily to mineralocorticoid receptor antagonism. The listed disease indications include:

• Aldosteronism
• Hypertension
• Chronic heart failure
• Sequelae of myocardial infarction
• Cirrhosis of the liver
• Renal failure
• Stroke

The patent claims are broader than the FDA-approved indication. FDA approval does not establish that every claimed compound or therapeutic use in the patent is clinically validated or commercially marketed.

What is the chemical scope of claim 1?

Claim 1 is a Markush compound claim covering a large family of substituted heteroaromatic compounds and their salts.

The principal structural elements are:

Claim element	Scope
Core variable D	N or C-R4
R4	Hydrogen, fluorine, trifluoromethyl, or C1-C4 alkyl
Ar	Substituted aromatic or heteroaromatic group
R1	C1-C4 alkyl, optionally fluorinated
R2	C1-C6 alkyl, optionally cycloalkyl- or fluorine-substituted, or sulfonyl substituent
R3	Hydrogen, fluorine, trifluoromethyl, or C1-C4 alkyl
R5	Hydrogen, fluorine, chlorine, cyano, nitro, trifluoromethyl, or C1-C4 alkyl
R6	Hydrogen or fluorine
R7	Halogen, alkyl, trifluoromethyl, alkoxy, or trifluoromethoxy
R8	Cyano or nitro
R9	Hydrogen, halogen, alkyl, alkoxy, alkylthio, dialkylamino, or substituted phenyl
R10	Hydrogen, halogen, or C1-C4 alkyl
E	CH, C-R7, or N
n	0, 1, or 2

The claim also covers pharmaceutically acceptable salts. This is important because a salt claim can reach a commercial form that differs from the neutral free compound while preserving the same active moiety.

Claim 1 has several enforcement characteristics:

1. It is composition-of-matter protection.
2. It covers a genus rather than one commercial molecule.
3. It includes multiple substitution patterns on the aromatic ring.
4. It covers both nitrogen-containing and carbon-substituted ring variants.
5. It reaches compounds with alkyl, fluorinated alkyl, sulfonyl, cyano, nitro, alkoxy, and halogen substitution.
6. It can cover stereoisomers and diastereomers when encompassed by the structural definition.
7. It extends to salts and, depending on claim construction, potentially crystalline or solvated forms of compounds within the formula.

The breadth of claim 1 makes written-description and enablement analysis important in litigation. A challenger could argue that the number of permutations is too large relative to the disclosed examples or that particular subgroups lack adequate support. Bayer would counter that the specification provides a common structural framework, synthetic routes, biological activity data, and representative examples.

How do claims 2 through 5 narrow the compound genus?

Claims 2 and 3 restrict the Markush variables to narrower substituent combinations. Claims 4 and 5 identify specific compounds, while claim 10 separately claims an individual compound.

Claim 2

Claim 2 narrows the structure by limiting:

• D to C-R4
• R4 to hydrogen, methyl, or trifluoromethyl
• R5 to hydrogen, fluorine, chlorine, or cyano
• R8 to cyano or nitro
• R9 to chlorine, bromine, alkyl, trifluoromethyl, alkoxy, trifluoromethoxy, alkylthio, or trifluoromethylthio
• R1 to methyl or trifluoromethyl
• R2 to C1-C4 alkyl, trifluoromethyl, or a lower alkyl/trifluoromethyl sulfonyl group
• R3 to hydrogen, methyl, or trifluoromethyl

Claim 2 is materially narrower than claim 1 but remains a genus claim.

Claim 3

Claim 3 is narrower still. It limits R9 to:

• Ethyl
• Methoxy
• Trifluoromethoxy

It limits R1 to methyl or trifluoromethyl, R2 to methyl, ethyl, n-propyl, or isopropyl, and R3 to hydrogen or methyl.

Claim 3 likely captures a smaller commercial and development-focused subset of the patent family. It is more vulnerable to design-around strategies than claim 1 because a competitor may change the R9, R1, R2, or R3 substituent while retaining mineralocorticoid receptor activity.

Claims 4, 5, and 10

Claims 4 and 5 claim specifically depicted compounds. Claim 10 also claims a specific compound and its salt. The structural drawings are not present in the supplied plaintext, so the exact chemical identities of those claims cannot be enumerated from the text alone.

These claims are typically stronger against direct commercial copying because they avoid some of the claim-construction disputes associated with a large Markush genus. They also provide fallback positions if claim 1 is narrowed or invalidated.

What does claim 6 protect?

Claim 6 is a manufacturing-process claim for preparing the formula (I) compounds.

The process has the following sequence:

1. React an aromatic compound of formula (II) with a compound of formula (III).
2. Form an intermediate of formula (IV).
3. Condense that intermediate with a compound of formula (V).
4. Alkylate the resulting formula (VI) intermediate.
5. Use either an alkylating reagent, a trialkyloxonium salt, or an orthoformate-based procedure.
6. Remove the ester-protecting group T, where T is allyl or 2-cyanoethyl.
7. Convert the resulting carboxylic acid to an imidazolide using 1,1'-carbonyldiimidazole.
8. React the imidazolide with ammonia to form the carboxamide.
9. Separate enantiomers or diastereomers where applicable.
10. Convert the product to a salt.

The process claim is significant because it can capture manufacturing routes even where a defendant disputes infringement of the compound claim. Its practical reach depends on whether a generic or third-party manufacturer uses the claimed sequence, reagents, intermediates, protecting groups, and order of operations.

A process that produces the same final compound through a materially different route may avoid literal infringement of claim 6. The doctrine of equivalents could still be relevant, but equivalence is fact-specific and subject to prosecution-history estoppel.

What pharmaceutical compositions and uses are protected?

Composition claim 7

Claim 7 covers a pharmaceutical composition containing a formula (I) compound and an inert, nontoxic, pharmaceutically acceptable excipient.

This is a conventional composition claim. It can reach tablets, capsules, suspensions, solutions, and other dosage forms if they contain a covered compound with suitable excipients.

Combination claim 8

Claim 8 covers compositions that combine the claimed compound with one or more additional active ingredients, including:

• ACE inhibitors
• Renin inhibitors
• Angiotensin II receptor blockers
• Beta-blockers
• Aspirin
• Diuretics
• Calcium-channel blockers
• Statins
• Digoxin derivatives
• Calcium sensitizers
• Nitrates
• Antithrombotic agents

This claim is directed to combination cardiovascular and renal therapy. Its scope may be relevant to fixed-dose combinations, co-packaged products, or treatment regimens involving concomitant therapy.

Treatment claim 9

Claim 9 covers the composition for treatment of the listed cardiovascular, renal, hepatic, and cerebrovascular conditions.

Because claim 9 is drafted as a composition-for-use claim rather than a conventional US method-of-treatment claim, its infringement analysis depends on claim construction, product labeling, induced infringement, and the jurisdiction in which enforcement occurs.

The claim may be relevant to a generic product if the proposed label instructs use for a patented indication. A generic applicant can seek a section viii carve-out for a patented use where FDA permits removal of the protected indication from the label.

When does US Patent 8,436,180 lose exclusivity?

The key dates are:

Event	Date
Earliest priority date	November 24, 2006
US patent grant	May 7, 2013
FDA approval of Kerendia	July 9, 2021
FDA-listed patent expiration	November 24, 2026
Five-year NCE exclusivity	Expected to expire July 9, 2026
Earliest practical generic-entry window	After applicable litigation stay and regulatory approval, generally late 2026 or thereafter

Kerendia received five years of new chemical entity exclusivity because finerenone was approved as a new active ingredient. That exclusivity is separate from the patent term and generally prevents FDA approval of an ANDA or 505(b)(2) application referencing the product before July 9, 2026, subject to statutory exceptions.

The November 24, 2026 patent date is the principal commercial loss-of-exclusivity date for the core patent. Actual generic entry can occur earlier only through a successful Paragraph IV challenge, settlement, license, or other authorized arrangement.

What is the Orange Book status of US 8,436,180?

US 8,436,180 is listed in the FDA Orange Book for Kerendia. The listed patent is associated with finerenone tablets and is a core composition-of-matter patent for the product.[2]

Orange Book listing matters because:

• An ANDA applicant must make a patent certification.
• A Paragraph IV certification can trigger patent litigation.
• Timely litigation can impose a 30-month stay on FDA approval.
• A first valid Paragraph IV filer may qualify for 180-day generic exclusivity.
• A patent listed for the active ingredient usually creates a stronger barrier than a formulation-only patent.

The Orange Book listing does not itself determine patent validity or enforceability. A listed patent can be invalidated, held unenforceable, or found not infringed.

Which companies are challenging Kerendia patents?

Public generic activity has focused on finerenone ANDA filings and Bayer litigation involving later-filed or Orange Book-listed patents. The most commercially relevant challengers are expected to include large generic manufacturers that file Paragraph IV certifications before the core patent expires.

The litigation record should be reviewed at the district-court docket level because:

• A Paragraph IV notice may not produce an immediately public lawsuit.
• Bayer may sue under multiple patents in the same action.
• Later patents can cover formulations, dosing, crystalline forms, or manufacturing processes.
• Settlement terms can change the authorized launch date without invalidating the patent.

The core commercial question is whether a challenger can obtain a final judgment before November 24, 2026 or secure an agreed launch date earlier than the unchallenged expiry date.

What other patents protect finerenone and Kerendia?

The commercial estate is broader than US 8,436,180. It may include:

Patent category	Commercial function
Core compound patents	Protect finerenone and related molecules
Specific-compound patents	Provide fallback protection for the marketed molecule
Formulation patents	Protect tablet composition, dosage strength, dissolution, or stability
Use patents	Protect treatment of chronic kidney disease, heart failure, or related conditions
Manufacturing patents	Restrict synthesis routes, intermediates, purification, or solid forms
Salt and solid-state patents	Protect specific salts, polymorphs, solvates, or crystalline forms
Regulatory patents	Listed in the Orange Book if they meet FDA listing requirements

Later patent filings can extend practical market protection beyond the core compound patent, but they do not automatically extend the full scope of the original composition-of-matter claim.

How strong is the patent estate for finerenone?

The estate is commercially strong for four reasons.

First, US 8,436,180 has composition-of-matter claims, which generally provide the broadest protection against unlicensed manufacture and sale.

Second, the patent includes narrower compound claims that can survive even if the broad Markush genus is challenged.

Third, the patent contains a process claim, creating a separate enforcement path against manufacturers that use the claimed synthesis.

Fourth, Kerendia has a regulated, prescription-only market with an approved renal and cardiovascular indication. Generic applicants cannot rely only on chemical identity; they must also address FDA labeling, bioequivalence, patent certifications, and potential litigation.

The principal weakness is age. The patent family has a 2006 priority date, leaving the core patent near the end of its term. The composition claim's breadth also creates potential validity pressure based on written description, enablement, anticipation, obviousness, and prosecution-history arguments.

What generic launch scenarios exist?

Scenario 1: No successful Paragraph IV challenge

Generic approval is blocked until the core patent expires and any applicable stay or exclusivity period ends. Commercial launch would likely occur after November 24, 2026.

Scenario 2: Bayer settles with a generic challenger

A settlement could permit an authorized or licensed generic launch before the nominal patent expiry. The actual date would depend on the agreement and any FTC or court review requirements.

Scenario 3: Challenger wins invalidity or noninfringement judgment

A successful Paragraph IV challenger could obtain FDA approval before patent expiration, subject to the 180-day exclusivity framework and any remaining regulatory exclusivity.

Scenario 4: Section viii carve-out

A generic applicant may remove a patented method of use from its label if the remaining label is legally and medically permissible. This route is more useful for method-of-use patents than for a core compound patent.

Does finerenone have biosimilar risk?

No. Finerenone is a chemically synthesized small molecule, not a biologic. It is subject to the ANDA generic pathway rather than the abbreviated biosimilar pathway under the Public Health Service Act.

The relevant competitive risks are:

• Paragraph IV ANDA filings
• Authorized generic entry
• At-risk launch
• Formulation or solid-state workarounds
• Process redesign
• Therapeutic substitution within the mineralocorticoid receptor antagonist class

How does finerenone compare with competing mineralocorticoid receptor antagonists?

Product	Active ingredient	Type	Key distinction
Kerendia	Finerenone	Nonsteroidal MRA	Cardiorenal use in CKD associated with type 2 diabetes
Inspra	Eplerenone	Steroidal MRA	Older cardiovascular and hypertension product
Aldactone	Spironolactone	Steroidal MRA	Broad low-cost generic use; endocrine adverse effects
Esaxerenone	Esaxerenone	Nonsteroidal MRA	Approved in Japan; different geographic and regulatory position

Finerenone's commercial differentiation is based on nonsteroidal structure, selective receptor activity, and clinical development in chronic kidney disease and cardiovascular risk reduction. Generic competition from spironolactone and eplerenone limits pricing power, but those products are not automatic substitutes for the FDA-approved Kerendia indication.

What geographic coverage does the patent family provide?

US 8,436,180 protects the US market only. Parallel patent family members may exist in Europe, Japan, China, Canada, Australia, and other jurisdictions through national-phase filings from the underlying international application.

Geographic risk varies because:

• Patent scope differs by national prosecution history.
• Patent term can differ because of regulatory extensions.
• Some jurisdictions may grant narrower claims.
• Supplementary protection certificates or equivalent extensions may apply outside the US.
• Generic launch timing may differ substantially by country.

A global launch analysis should separate US Orange Book exposure from European, Japanese, Chinese, and other national patent positions.

Key Takeaways

• US 8,436,180 is a core Bayer composition-of-matter patent for finerenone-related compounds.
• Claim 1 is a broad Markush genus covering substituted heteroaromatic carboxamides and salts.
• Claims 2 and 3 narrow the genus; claims 4, 5, and 10 cover specific compounds.
• Claim 6 protects a multistep manufacturing route using protected ester intermediates and amide formation.
• Claims 7 through 9 cover pharmaceutical compositions, combination therapy, and treatment applications.
• Finerenone is marketed as Kerendia and was FDA-approved in 2021.
• The core Orange Book-listed patent expiration date is November 24, 2026.
• Finerenone is a small molecule, so generic ANDA litigation, not biosimilar litigation, is the relevant competitive pathway.
• The principal commercial risks are Paragraph IV challenges, settlement-based entry, later formulation or use patents, and process redesign.
• Claims 4, 5, and 10 cannot be chemically identified from the supplied text because their structural drawings were omitted.

FAQs

Is US 8,436,180 a finerenone patent?

Yes. The patent covers the finerenone chemical class and is associated with Kerendia's core US patent protection.

Can a generic company avoid US 8,436,180 by using a different salt?

Not necessarily. Claim 1 expressly covers salts. A different salt can still infringe if the underlying compound falls within the claimed formula.

Does the patent cover spironolactone or eplerenone?

No. Spironolactone and eplerenone are structurally distinct steroidal mineralocorticoid receptor antagonists and are not covered merely because they share the same pharmacologic target.

Can a generic manufacturer avoid claim 6 by using a different synthesis?

Potentially. A materially different synthesis may avoid literal infringement of the process claim, although the final compound may still infringe the composition claims.

Does FDA approval of Kerendia extend the patent term?

FDA approval does not automatically extend the patent. Patent-term extension, if granted, requires a separate statutory determination and is distinct from FDA regulatory exclusivity.

References

1. United States Patent and Trademark Office. (2013). US Patent No. 8,436,180, substituted compounds and pharmaceutical compositions.
2. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
3. Bayer Pharma Aktiengesellschaft. (2013). US Patent No. 8,436,180 prosecution and patent-family records. United States Patent and Trademark Office.
4. World Intellectual Property Organization. (2008). International patent publication and family records for substituted heteroaromatic compounds. PATENTSCOPE.
5. U.S. Food and Drug Administration. (2021). Kerendia (finerenone) prescribing information. FDA.

Drugs Protected by US Patent 8,436,180

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Bayer Hlthcare	KERENDIA	finerenone	TABLET;ORAL	215341-001	Jul 9, 2021		RX	Yes	No	8,436,180		Y	Y
Bayer Hlthcare	KERENDIA	finerenone	TABLET;ORAL	215341-002	Jul 9, 2021		RX	Yes	No	8,436,180		Y	Y
Bayer Hlthcare	KERENDIA	finerenone	TABLET;ORAL	215341-003	Jul 11, 2025		RX	Yes	Yes	8,436,180		Y	Y

Foreign Priority and PCT Information for Patent: 8,436,180

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Germany	10 2007 009 494	Feb 27, 2007

PCT Information
PCT Filed	February 19, 2008	PCT Application Number:	PCT/EP2008/001257
PCT Publication Date:	September 04, 2008	PCT Publication Number:	WO2008/104306

International Family Members for US Patent 8,436,180

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	2132206		C02132206/01	Switzerland
European Patent Office	2132206		LUC00260	Luxembourg
European Patent Office	2132206		PA2022512	Lithuania
European Patent Office	2132206		122022000030	Germany