United States Patent 6,395,728: Scope, Claims, Expiration, Litigation, and Patent Landscape for Valsartan-Amlodipine

U.S. Patent No. 6,395,728 protected pharmaceutical combinations containing valsartan, an angiotensin II AT1-receptor antagonist, and amlodipine, a calcium-channel blocker. Its strongest claim was composition claim 2, which covered a pharmaceutical combination consisting essentially of the two active ingredients and a carrier. The patent was associated with Novartis’ Exforge product and has expired. It no longer creates a live U.S. patent barrier to generic valsartan-amlodipine products.

What invention does U.S. Patent 6,395,728 protect?

The patent covers the use and formulation of valsartan with amlodipine for treating or preventing hypertension, particularly hypertension associated with diabetes.

The patent’s claim structure has two principal categories:

A method-of-treatment claim covering administration to a mammal.
Composition claims covering the combined pharmaceutical product.

The patent does not claim valsartan or amlodipine individually. It claims their combination.

Patent element	Scope
AT1 antagonist	Specifically valsartan or a pharmaceutically acceptable salt
Calcium-channel blocker	Specifically amlodipine or a pharmaceutically acceptable salt
Treatment claim	Treatment or prevention of hypertension associated with diabetes
Composition claim	Combination composition containing valsartan, amlodipine, and a pharmaceutically acceptable carrier
Oral dosage range for valsartan	About 10 mg to about 200 mg
Oral dosage range for amlodipine	About 1.0 mg to about 180 mg
Covered subject	Mammals, including humans
Product type	Fixed-dose product or other pharmaceutical combination composition, depending on claim construction

The patent issued on May 28, 2002, to Novartis AG. The patent is titled “Pharmaceutical combination comprising an AT1-antagonist and a calcium channel blocker.” [1]

How should claim 1 of U.S. Patent 6,395,728 be interpreted?

Claim 1 is a method-of-treatment claim. It requires all of the following:

A method for treating or preventing hypertension.
The hypertension must be associated with diabetes.
Administration to a mammal in need of treatment.
Administration of a therapeutically effective amount.
A combination consisting essentially of valsartan and amlodipine, or pharmaceutically acceptable salts of those compounds.
A pharmaceutically acceptable carrier.

Claim 1 does not expressly require oral administration. It also does not specify a particular dose, ratio, tablet architecture, release profile, or fixed-dose tablet.

What does “consisting essentially of” mean in claim 1?

“Consisting essentially of” is a partially closed transition. It generally permits additional ingredients that do not materially alter the basic and novel characteristics of the claimed combination.

The basic claimed combination is valsartan plus amlodipine. Excipients, carriers, coatings, stabilizers, binders, disintegrants, and other conventional formulation ingredients would generally be compatible with the claim if they do not materially change the combination’s intended characteristics.

The phrase is narrower than “comprising,” but broader than “consisting of.” A product containing valsartan, amlodipine, and conventional inactive ingredients could fall within the claim. A third pharmacologically active antihypertensive ingredient could create a claim-construction issue because it may materially affect the claimed combination.

Does claim 1 require treatment of diabetic patients?

Yes. Claim 1 expressly limits the indication to hypertension associated with diabetes. A method using valsartan and amlodipine for uncomplicated hypertension would not automatically satisfy every limitation of claim 1.

That limitation did not eliminate the importance of the composition claims. Claim 2 has no express diabetes or hypertension limitation and therefore was the broader product-oriented claim.

What does claim 2 cover?

Claim 2 covers a pharmaceutical combination composition consisting essentially of:

Valsartan or a pharmaceutically acceptable salt;
Amlodipine or a pharmaceutically acceptable salt; and
A pharmaceutically acceptable carrier.

Claim 2 is materially broader than claim 1 because it does not require:

Treatment of hypertension;
Prevention of hypertension;
Diabetes-associated hypertension;
A human or other identified patient;
Oral administration;
A specified dose;
A particular valsartan-to-amlodipine ratio; or
A particular dosage form.

Claim 2 could therefore reach a broad range of tablets, capsules, powders, granules, or other pharmaceutical compositions containing both active ingredients, subject to the claim’s “consisting essentially of” language.

What dosage ranges are protected by claims 3 and 4?

Claims 3 and 4 narrow claim 2 by adding oral dosage ranges.

Claim	Active ingredient	Claimed amount
Claim 3	Valsartan	About 10 mg to about 200 mg
Claim 4	Amlodipine	About 1.0 mg to about 180 mg

The claims use “about,” which ordinarily gives some tolerance around the stated numerical endpoints. The precise scope depends on claim construction, specification disclosures, prosecution history, and the technical context.

How do the claims compare with Exforge strengths?

Exforge was commercialized in valsartan/amlodipine strengths including 5/80 mg, 5/160 mg, 10/160 mg, and later 10/320 mg presentations, depending on the market and regulatory period. [2]

The 80 mg and 160 mg valsartan strengths fall within claim 3. The 5 mg and 10 mg amlodipine strengths fall within claim 4. A 320 mg valsartan strength would not fall within the literal numerical range of claim 3, although claim 2 does not contain a stated dosage limitation.

Product strength	Claim 3 valsartan range	Claim 4 amlodipine range
5 mg / 80 mg	Within	Within
5 mg / 160 mg	Within	Within
10 mg / 160 mg	Within	Within
10 mg / 320 mg	Outside claim 3 range	Within claim 4 range

The presence of a strength outside claim 3 would not by itself avoid claim 2.

What patents protected Exforge and the valsartan-amlodipine combination?

U.S. Patent 6,395,728 was the foundational combination patent associated with valsartan and amlodipine. The broader Exforge patent estate also included later patents directed to formulation, solid-state, dosage, or related product characteristics.

The relevant patent categories were:

Patent category	Subject matter	Commercial significance
Combination patent	Valsartan plus amlodipine	Core product combination
Method-of-use patent	Treatment of hypertension and related conditions	Potential use restriction
Formulation patent	Tablet composition, excipients, stability, or release characteristics	Product-specific protection
Solid-state or salt patent	Particular active form or salt	Manufacturing and formulation control
Regulatory exclusivity	FDA approval-related exclusivity	Separate from patent rights

U.S. Patent 6,395,728 should not be treated as covering every valsartan or amlodipine product. Its claim scope is directed to the paired active ingredients.

When did U.S. Patent 6,395,728 expire?

The patent’s listed expiration date was September 21, 2020. The expiration reflected the applicable U.S. patent-term calculation and any adjustment reflected in the patent and regulatory records. [1, 3]

The practical consequences are direct:

The patent cannot now support an ordinary U.S. infringement action based on post-expiration manufacture, sale, or use.
A generic manufacturer no longer needs to design around the expired claims.
A Paragraph IV challenge directed only to this patent no longer presents a current injunction risk.
The patent cannot independently delay FDA approval of a new ANDA.

Expiration of this patent does not establish that every later patent in the Exforge estate expired at the same time. Patent-by-patent review remains necessary for later formulation, dosage-form, or solid-state patents.

What was the Orange Book status of U.S. Patent 6,395,728?

The patent was listed in connection with Exforge, the FDA-approved combination of amlodipine besylate and valsartan. [3, 4]

An Orange Book listing identifies a patent that the innovator represented as covering the approved drug or an approved method of use. It does not determine infringement, validity, enforceability, or claim construction.

For generic applicants, the listing historically created a Hatch-Waxman certification issue:

Paragraph I: no patent information was listed;
Paragraph II: the listed patent had expired;
Paragraph III: the ANDA applicant would wait until expiration;
Paragraph IV: the applicant asserted that the patent was invalid, unenforceable, or not infringed.

While the patent was in force, a Paragraph IV notice could trigger patent litigation and a 30-month stay of FDA approval under the Hatch-Waxman framework. [5] After expiration, the patent moved into a Paragraph II posture for practical regulatory purposes.

Which companies challenged Exforge patent protection?

Generic competition for amlodipine-valsartan involved ANDA applicants seeking approval for products equivalent to Exforge. The competitive field included major generic manufacturers such as Teva, Sandoz, Mylan, Dr. Reddy’s, Lupin, and other ANDA sponsors, depending on the strength, filing date, and market authorization at issue.

The relevant challenge mechanisms included:

Paragraph IV certifications against unexpired listed patents;
Paragraph III certifications providing for launch after patent expiration;
Declaratory or infringement litigation involving listed patents;
Settlements establishing an agreed generic-entry date;
At-risk launch analysis after patent expiry.

Because U.S. Patent 6,395,728 has expired, any current competitive assessment must focus on later-listed patents, FDA approval status, ANDA exclusivity, and formulation differences rather than this patent.

What patent litigation affected valsartan-amlodipine products?

Patent litigation involving Exforge generally centered on whether generic products infringed listed combination, formulation, or related patents. The principal legal issues in this category were:

Whether a generic product contained both claimed active ingredients;
Whether the generic’s dosage form satisfied the composition limitations;
Whether “consisting essentially of” excluded additional active ingredients;
Whether the claimed use limitation was present in labeling or induced use;
Whether the patent was valid in view of prior art;
Whether the patent was enforceable;
Whether settlement terms limited the timing of generic entry.

The expiration of U.S. Patent 6,395,728 ends the forward-looking enforcement value of that patent. It does not erase historical litigation exposure for activity occurring before expiration. Nor does it resolve disputes involving separate patents.

No current U.S. injunction or settlement can extend the term of an expired patent. A settlement could have governed launch timing during the patent term, but it cannot revive the expired patent rights.

What generic entry risks remain after expiration?

The direct risk from Patent 6,395,728 is zero for post-expiration U.S. entry. Remaining risks are commercial and regulatory rather than based on this patent.

Formulation and product-design risks

A generic product may still encounter later patents covering:

Specific excipient combinations;
Tablet hardness or dissolution profiles;
Stability-enhancing formulations;
Particular crystalline or salt forms;
Manufacturing processes;
Dosing regimens;
Labeling directed to patented uses.

A manufacturer can reduce exposure by using a formulation that does not practice later claims and by adopting a label that avoids patented method-of-use indications where legally available.

Regulatory risks

FDA approval can remain affected by:

Unexpired Orange Book patents;
30-month stays from Paragraph IV litigation;
First-filer 180-day exclusivity;
Paragraph III certification timing;
Product-specific bioequivalence requirements;
Separate approval requirements for different strengths.

FDA approval of a generic combination product does not require infringement of every claim in an expired patent. It requires compliance with the ANDA pathway and applicable patent-certification rules. [5]

Manufacturing and supply risks

The active ingredients are established small molecules with multiple global suppliers. Manufacturing barriers are therefore lower than for biologics. The more relevant barriers are:

API quality and impurity control;
Stability of the dual-active formulation;
Consistent dissolution performance;
Regulatory approval of the selected manufacturing site;
Freedom to operate under later formulation or process patents.

Biosimilar risk is not material. Valsartan and amlodipine are chemically synthesized small molecules, not biologic products subject to the biosimilar pathway.

How strong was the patent estate for valsartan-amlodipine?

U.S. Patent 6,395,728 was commercially strong during its term because claim 2 was a broad composition claim covering the core two-drug combination without a disease or dosage limitation.

Its strengths were:

Direct coverage of the active-ingredient pair;
No requirement for a specific ratio;
No limitation to a named brand;
No requirement for a particular tablet technology;
Broad product-oriented composition language.

Its limitations were:

Expiration in 2020;
Dependence on the meaning of “consisting essentially of”;
Narrower scope for claim 1 because of the diabetes-associated hypertension limitation;
Numerical constraints in claims 3 and 4;
Potential design-around options involving separate administration, different active ingredients, or products outside the claimed composition.

Strength factor	Assessment
Core combination coverage	Strong during term
Method-of-use coverage	Narrower because of diabetes limitation
Dosage coverage	Broad in claim 2, limited in claims 3 and 4
Formulation specificity	Limited on the face of the supplied claims
Current enforceability	None after expiration
Biosimilar exposure	Not applicable
Generic design-around potential	Moderate during term; high after expiration

How does Patent 6,395,728 compare with competing antihypertensive patent estates?

Valsartan-amlodipine is a small-molecule combination product. Its patent profile differs from products protected primarily by molecule patents, biologic patents, or device patents.

Product type	Primary patent risk	Generic or follow-on pathway
Valsartan-amlodipine	Combination and formulation patents	ANDA
Single-agent valsartan	Active ingredient, formulation, and use patents	ANDA
Amlodipine products	Formulation and combination patents	ANDA
Biologic antihypertensive	Composition, manufacturing, and formulation patents	Biosimilar pathway
Drug-device combination	Device, formulation, and use patents	NDA or ANDA depending on product

The key commercial distinction is that the expired patent no longer blocks a generic from combining two off-patent small molecules. Later patents may still affect a specific product design, but those patents must be analyzed separately.

What is the commercial impact of expiration?

Expiration removes the principal patent-based barrier to competing valsartan-amlodipine products. Commercial effects typically include:

Multiple generic entrants;
Price compression;
Reduced branded share;
Channel substitution;
Lower net sales for the originator;
Greater use of pharmacy substitution;
Increased importance of supply reliability and contract pricing.

Revenue exposure should be measured against Exforge sales before generic erosion, not against current sales alone. The patent expiration date is historical, so current valuation work should use present generic penetration, branded reimbursement, authorized-generic arrangements, and any remaining later patent rights.

Key Takeaways

U.S. Patent 6,395,728 claimed the combination of valsartan and amlodipine.
Claim 1 covered treatment or prevention of diabetes-associated hypertension.
Claim 2 was the broadest commercially important claim because it covered the pharmaceutical combination without a disease, dose, or oral-use limitation.
Claims 3 and 4 added oral dosage ranges for valsartan and amlodipine.
The patent was associated with Novartis’ Exforge product.
The listed U.S. expiration date was September 21, 2020.
The patent is expired and cannot create a current U.S. entry barrier.
Generic and licensing analysis must now focus on later Orange Book patents, formulation claims, regulatory exclusivity, and market access.
Biosimilar analysis is not relevant because valsartan and amlodipine are small-molecule drugs.
The core combination patent was strong during its term but has no remaining forward-looking enforcement value.

FAQs About U.S. Patent 6,395,728

Does U.S. Patent 6,395,728 cover Exforge specifically?

No. It covers the valsartan-amlodipine combination, not the Exforge trademark. A competing product containing the claimed active ingredients could have implicated the patent during its term.

Is valsartan 320 mg covered by claim 3?

Not literally by the stated 10 mg to 200 mg range. Claim 2 does not contain that dosage limitation and could have presented a separate infringement issue during the patent term.

Does the patent cover separate valsartan and amlodipine tablets?

Claim 1 concerns administering a combination and does not expressly require a single tablet. Claim 2 recites a combination composition. Whether separate dosage forms satisfy a particular claim would depend on the claim language, specification, prosecution history, and facts of the product.

Can the expired patent block a new generic application?

No. An expired patent cannot support a new injunction against post-expiration commercial activity or independently delay FDA approval. Other unexpired listed patents may still affect the application.

Are valsartan-amlodipine products subject to biosimilar competition?

No. They are chemically synthesized small-molecule products regulated through the generic-drug framework, primarily the ANDA pathway, rather than the biosimilar pathway.

References

United States Patent and Trademark Office. (2002). U.S. Patent No. 6,395,728: Pharmaceutical combination comprising an AT1-antagonist and a calcium channel blocker.
Novartis Pharmaceuticals Corporation. (2020). Exforge (amlodipine besylate and valsartan) prescribing information.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations.
U.S. Food and Drug Administration. (2007). Drugs@FDA: Exforge application and labeling records.
U.S. Food and Drug Administration. (2024). Small business assistance: 180-day generic drug exclusivity and patent certifications under the Hatch-Waxman Amendments.

Details for Patent: 6,395,728

Summary for Patent: 6,395,728