Details for Patent: 9,066,936

« Back to Dashboard

Which drugs does patent 9,066,936 protect, and when does it expire?

Patent 9,066,936 protects EDARBI and EDARBYCLOR and is included in two NDAs.

This patent has twenty-one patent family members in seventeen countries.

Summary for Patent: 9,066,936

Title:	Solid pharmaceutical composition comprising a benzimidazole-7-carboxylate derivative and a pH control agent
Abstract:	The present invention provides a solid pharmaceutical composition containing compound (I) having an angiotensin II receptor antagonistic action and defined in the specification and a pH control agent, which composition is superior in the stability and dissolution property of compound (I).
Inventor(s):	Shuji Yoneyama, Yutaka Tanoue
Assignee:	Takeda Pharmaceutical Co Ltd
Application Number:	US12/450,403
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 9,066,936
Patent Claim Types: see list of patent claims	Use; Composition; Formulation;

US Patent 9,066,936: Azilsartan Medoxomil Potassium Formulation Scope, Patent Landscape, and Generic Entry Risk

US Patent 9,066,936 protects a solid pharmaceutical composition containing azilsartan medoxomil potassium and a solid pH-control agent that produces a pH of 3 to 5 in water at 1% w/v and 25°C. Claim 2 narrows the formulation to monosodium fumarate or fumaric acid combined with sodium hydroxide. Claim 3 protects the use of that pH-control system to stabilize the active ingredient or improve dissolution.

The patent is formulation-focused. It does not broadly claim azilsartan medoxomil as a chemical compound, all azilsartan products, or every tablet containing the active ingredient. Infringement generally requires proof that a competing solid product contains the claimed active salt and a qualifying solid acid or buffer system.

What drug and formulation does US Patent 9,066,936 protect?

The compound identified in the claims is azilsartan medoxomil potassium, the active pharmaceutical ingredient used in Edarbi, Takeda Pharmaceutical Company Limited's antihypertensive product. Azilsartan medoxomil is an orally administered prodrug of azilsartan, an angiotensin II receptor blocker.

The patent protects a formulation architecture with four central elements:

Claim element	Requirement
Dosage form	Solid pharmaceutical composition
Active ingredient	Azilsartan medoxomil potassium
pH-control component	Solid agent
Functional pH limitation	pH of 3 to 5 when dissolved or suspended at 1% w/v in water at 25°C

The pH limitation is not necessarily the pH of the finished tablet. It is a test condition applied to the pH-control agent after dissolution or suspension in water. That distinction is important. A tablet manufacturer could not avoid the claim merely by showing that the intact tablet has no measurable pH.

The claim also does not require a particular tablet shape, coating, excipient percentage, manufacturing process, dissolution profile, or commercial strength. Unless restricted by another claim or specification-based construction, the composition can include conventional pharmaceutical excipients.

How broad is claim 1 of US 9,066,936?

Claim 1 is an open-ended composition claim because it uses "comprising." A product may contain ingredients beyond azilsartan medoxomil potassium and the pH-control agent while remaining within the claim.

A likely infringement analysis would ask:

1. Does the product contain azilsartan medoxomil potassium?
2. Is the product a solid pharmaceutical composition?
3. Does it contain a solid pH-control agent?
4. Does that agent produce a pH from 3 to 5 under the specified test conditions?

The claim does not require the pH-control agent to be the only acidifying ingredient. A product containing monosodium fumarate plus other buffers could still satisfy the "comprising" language if the combined formulation meets the claim limitations.

The claim is narrower than a claim to any acidic azilsartan medoxomil formulation. The pH range, solid-state requirement, and active salt identity create cumulative limitations.

What does "solid pharmaceutical composition" mean?

The most natural embodiments are tablets, capsules containing a solid blend, granules, powders, and other dry oral dosage forms. A liquid formulation would generally fall outside claim 1 because the composition itself must be solid.

A tablet made by wet granulation can still be a solid pharmaceutical composition. The relevant issue is the marketed dosage form and its ingredients, not whether water was used during manufacture.

What does the pH limitation require?

The patent claim uses a functional test:

• concentration: 1% w/v;
• temperature: 25°C;
• medium: water;
• physical state: dissolved or suspended;
• result: pH 3 to 5.

The test may create factual disputes concerning:

• water volume and grade;
• equilibration time;
• agitation;
• suspension versus complete dissolution;
• sample preparation;
• whether the test applies to the isolated pH-control agent or the complete composition;
• calibration and measurement procedure.

A generic manufacturer could challenge infringement by showing that its selected solid acid, buffer, or salt produces a pH below 3 or above 5 under the claim's specified conditions. That defense would depend on reproducible analytical data.

What does claim 2 add to the patent protection?

Claim 2 depends on claim 1 and identifies two specific pH-control systems:

1. monosodium fumarate; or
2. fumaric acid combined with sodium hydroxide.

Because it depends on claim 1, claim 2 still requires:

• azilsartan medoxomil potassium;
• a solid pharmaceutical composition; and
• the claimed pH behavior.

Claim 2 is narrower in ingredient identity but potentially easier to enforce where a product label, formulation patent, manufacturing record, or reverse-engineering analysis identifies fumarate chemistry.

The alternative "fumaric acid and sodium hydroxide" may cover a formulation in which the two materials are introduced separately and react in situ, as well as a process that produces monosodium fumarate before tableting. The precise scope would depend on the specification, prosecution history, and claim-construction record.

What does claim 3 protect?

Claim 3 is a method claim directed to two stated objectives:

• stabilizing azilsartan medoxomil potassium in a solid pharmaceutical composition; or
• improving dissolution of azilsartan medoxomil potassium from a solid pharmaceutical composition.

The method requires adding a pH-control agent with the claimed pH property to a solid composition containing the active ingredient.

Claim 3 may reach conduct that does not present the same proof structure as claim 1. A composition claim focuses on what is present in the finished product. A method claim focuses on the act of adding the pH-control agent for stabilization or dissolution improvement.

The claim raises several legal issues:

• whether "stabilizing" requires a measured improvement over a control;
• whether "improving dissolution" requires a specified dissolution method or statistically significant result;
• whether the pH-control agent must be added during formulation or can be blended later;
• whether a manufacturer or supplier performs every claimed step;
• whether the method is practiced domestically;
• whether indirect infringement can be established from instructions supplied to a generic manufacturer.

A generic product may face method-claim exposure even if its label does not expressly describe the formulation as a stabilization technology. Proof would likely rely on the product composition, development records, manufacturing instructions, and dissolution data.

What patents protect azilsartan medoxomil beyond US 9,066,936?

Azilsartan medoxomil has a layered patent estate rather than a single patent category.

Patent layer	Typical subject matter	Relevance to generic entry
Compound patents	Azilsartan, azilsartan medoxomil, salts and related compounds	Can block the active ingredient itself
Formulation patents	Acidic pH control, stability, dissolution, tablet composition	Can block particular finished products
Method-of-use patents	Treatment of hypertension and related cardiovascular indications	May affect label strategy and skinny-label entry
Process patents	Preparation, crystallization, salt formation, or purification	Can affect manufacturing route
Solid-state patents	Polymorphs, hydrates, solvates, particle properties	Can restrict use of particular solid forms
Combination patents	Azilsartan medoxomil with other antihypertensives	Relevant to combination products

US 9,066,936 is most important in the formulation category. It does not, based on the supplied claims, establish ownership of every manufacturing route or every solid form of azilsartan medoxomil potassium.

The practical freedom-to-operate question is therefore cumulative. A manufacturer could avoid US 9,066,936 and still face a separate compound, process, solid-state, or method-of-use patent.

What is the Orange Book status of US 9,066,936?

The Orange Book analysis must distinguish three issues:

1. whether the patent is listed for the approved Edarbi product;
2. whether the listed claims cover the drug substance, drug product, or method of use; and
3. whether an ANDA applicant must make a Paragraph IV certification.

The supplied claims are drug-product and method claims. If listed for Edarbi, they would normally be relevant to an ANDA directed to azilsartan medoxomil tablets, particularly where the proposed formulation uses the claimed pH-control system.

An ANDA applicant can respond through:

• Paragraph III certification, accepting delayed approval until patent expiration;
• Paragraph IV certification, asserting that the patent is invalid, unenforceable, or not infringed;
• a Section VIII statement, where an applicable method-of-use listing can be carved out;
• a formulation redesign that removes the claimed pH-control agent or falls outside the pH range.

A Section VIII strategy is less useful against a composition claim. A generic applicant cannot avoid a composition patent merely by removing a method-of-use statement from its label.

The Orange Book listing, expiration date, pediatric exclusivity, patent-term adjustment, and any regulatory exclusivity must be verified against the current FDA publication and the patent's USPTO term records. Those dates are not established by the claim text alone. [1, 2]

When does US Patent 9,066,936 lose exclusivity?

The patent's enforceable expiration date cannot be calculated from the claims alone. It depends on:

• the earliest effective nonprovisional or international filing date;
• any patent-term adjustment;
• any terminal disclaimer;
• any patent-term extension;
• statutory and regulatory exclusivity separate from patent term.

The patent was issued in 2015 as US Patent 9,066,936. The relevant commercial question is not the grant date but the adjusted expiration date recorded in USPTO and FDA databases.

A formulation patent can remain commercially important after an earlier compound patent expires. If US 9,066,936 has a later expiration date than the core azilsartan medoxomil patent, a generic manufacturer may have an active-ingredient pathway but still need a formulation redesign or litigation strategy.

What Paragraph IV challenges and litigation risks exist?

A Paragraph IV applicant would likely attack this patent on three fronts.

Noninfringement

The applicant could argue that its product:

• does not contain azilsartan medoxomil potassium;
• is not a solid pharmaceutical composition;
• uses a pH-control agent outside the 3 to 5 range;
• uses a non-solid or liquid pH modifier;
• contains a different salt or active form;
• does not practice the claimed stabilization or dissolution method.

Analytical testing would be central. A formulation using a different acid or buffer may avoid claim 2 while still requiring analysis under claim 1.

Invalidity

Potential invalidity theories include:

• anticipation by an earlier azilsartan formulation;
• obviousness based on known acidification and stabilization techniques;
• indefiniteness of the pH test or functional limitations;
• lack of written description for the full range of pH-control agents;
• lack of enablement across the entire claimed formulation space.

The pH range of 3 to 5 may be attacked as an obvious optimization if prior art disclosed acidic formulations and the specification did not show a meaningful technical effect across the full range. The patent holder would likely rely on comparative stability or dissolution data to establish a formulation advantage.

Enforceability

The principal enforceability risks would arise from prosecution conduct, disclosure of material prior art, claim amendments, and representations made to the USPTO. The supplied claims do not establish whether such defenses exist.

No particular Paragraph IV challenger, settlement agreement, or final infringement judgment can be established from the claim text. Those issues require review of FDA ANDA records, federal court dockets, and public settlement disclosures.

How strong is the patent estate for generic launch risk?

The individual formulation patent is moderately narrow but commercially meaningful.

Risk factor	Assessment
Active ingredient coverage	Narrowly tied to azilsartan medoxomil potassium
Dosage-form coverage	Broad across solid oral compositions
Excipient coverage	Broad in claim 1, specific in claim 2
Functional limitation	Creates testing and construction disputes
Design-around potential	Meaningful, through alternative pH-control systems
Method-claim exposure	Potentially material for formulation and development conduct
Litigation leverage	Stronger if listed in the Orange Book and supported by multiple related patents
Standalone blocking power	Limited if a noninfringing formulation can be developed

The greatest risk arises where a proposed generic reproduces the reference product's excipient system, particularly monosodium fumarate or a fumaric-acid/sodium-hydroxide system. A formulation using a different acidifying agent may reduce claim 2 exposure but still require analysis under claim 1.

What generic launch scenarios exist?

Scenario 1: Same formulation

A generic using azilsartan medoxomil potassium with monosodium fumarate presents the highest direct infringement risk. A Paragraph IV challenge would likely be required if the patent remains listed and unexpired.

Scenario 2: Alternative acid or buffer

A generic using another solid pH-control agent may avoid claim 2. It would still need to determine whether the agent produces a pH of 3 to 5 under the claim's test conditions.

Scenario 3: Non-solid pH-control system

A liquid or otherwise non-solid pH modifier may avoid the express solid-agent limitation, but the finished product must still be evaluated against the full claim construction.

Scenario 4: Different active form

A product using a different active salt, polymorph, or chemical form may avoid this patent. It could remain exposed to separate compound or solid-state patents.

Scenario 5: Paragraph III launch

An applicant may accept the patent and delay approval until the applicable patent term ends. This avoids litigation but postpones market entry.

How does US 9,066,936 compare with a compound patent?

A compound patent generally has broader commercial reach because it can cover the active ingredient regardless of tablet excipients or manufacturing method. US 9,066,936 is narrower because it requires a specific solid formulation environment.

The formulation patent may have greater practical relevance after compound-patent expiry if the reference product's stability depends on the claimed acidification strategy. Its value is highest when:

• the FDA-approved product uses the claimed formulation;
• the patent is listed in the Orange Book;
• alternative formulations have inferior stability or dissolution;
• multiple related patents cover alternative designs;
• generic manufacturers cannot easily separate the active from the claimed excipient system.

Is there a biosimilar risk for azilsartan medoxomil?

No. Azilsartan medoxomil is a chemically synthesized small-molecule drug, not a biologic. Competitive entry proceeds through the ANDA pathway for generics, not the biosimilar pathway under the Biologics Price Competition and Innovation Act.

The relevant barriers are pharmaceutical formulation, patent certification, manufacturing, bioequivalence, and litigation risk.

Key Takeaways

• US 9,066,936 is directed to solid formulations of azilsartan medoxomil potassium.
• Claim 1 requires a solid pH-control agent producing pH 3 to 5 at 1% w/v and 25°C.
• Claim 2 specifically covers monosodium fumarate and fumaric acid combined with sodium hydroxide.
• Claim 3 covers stabilization and dissolution-improvement methods using the claimed pH-control system.
• The patent does not, on the supplied claims, cover azilsartan medoxomil in every dosage form.
• A generic using the reference formulation faces the highest infringement risk.
• Alternative solid buffers, non-solid pH modifiers, or different active forms may provide design-around routes.
• The exact patent expiration date, Orange Book listing, Paragraph IV activity, litigation history, and settlement status require review of current FDA, USPTO, and court records.
• Azilsartan medoxomil is a small molecule, so biosimilar risk is not applicable.

FAQs

Does US Patent 9,066,936 cover Edarbi tablets?

It may cover Edarbi tablets if the marketed product contains azilsartan medoxomil potassium and a pH-control system meeting the claimed limitations. Product-specific coverage depends on the FDA-listed formulation and analytical testing.

Can a generic avoid the patent by changing the tablet coating?

Usually not. A coating change does not remove the core limitations if the tablet still contains the claimed active ingredient and qualifying solid pH-control agent.

Does monosodium fumarate automatically infringe claim 2?

No. The product must also satisfy every limitation of claim 1, including the solid composition requirement, azilsartan medoxomil potassium, and the pH 3 to 5 test.

Can a generic use fumaric acid without sodium hydroxide?

It may avoid the specific alternative in claim 2, but it could still fall within claim 1 if the resulting solid pH-control system meets the functional pH limitation.

Is a Paragraph IV certification required for every azilsartan generic?

No. The certification depends on the patents listed for the reference product, their expiration status, the proposed formulation, and whether the applicant can use a Paragraph III or other applicable certification strategy.

References

1. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations. FDA Center for Drug Evaluation and Research.

2. United States Patent and Trademark Office. (n.d.). Patent term adjustment and patent term information. U.S. Department of Commerce.

3. U.S. Patent No. 9,066,936. (2015). Pharmaceutical composition containing azilsartan medoxomil potassium salt. United States Patent and Trademark Office.

4. U.S. Food and Drug Administration. (n.d.). Edarbi prescribing information. FDA Center for Drug Evaluation and Research.

Drugs Protected by US Patent 9,066,936

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Azurity	EDARBI	azilsartan kamedoxomil	TABLET;ORAL	200796-001	Feb 25, 2011	AB	RX	Yes	No	9,066,936		Y
Azurity	EDARBI	azilsartan kamedoxomil	TABLET;ORAL	200796-002	Feb 25, 2011	AB	RX	Yes	Yes	9,066,936		Y
Azurity	EDARBYCLOR	azilsartan kamedoxomil; chlorthalidone	TABLET;ORAL	202331-001	Dec 20, 2011	AB	RX	Yes	No	9,066,936		Y
Azurity	EDARBYCLOR	azilsartan kamedoxomil; chlorthalidone	TABLET;ORAL	202331-002	Dec 20, 2011	AB	RX	Yes	Yes	9,066,936		Y

Foreign Priority and PCT Information for Patent: 9,066,936

PCT Information
PCT Filed	March 26, 2008	PCT Application Number:	PCT/JP2008/056522
PCT Publication Date:	October 16, 2008	PCT Publication Number:	WO2008/123536

International Family Members for US Patent 9,066,936

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	065850
Australia	2008235790
Brazil	PI0809522
Canada	2681143
Chile	2008000868
China	101677961