Details for Patent: 8,685,934

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Which drugs does patent 8,685,934 protect, and when does it expire?

Patent 8,685,934 protects XIGDUO XR and FARXIGA and is included in two NDAs.

Protection for XIGDUO XR has been extended six months for pediatric studies, as indicated by the *PED designation in the table below.

This patent has seven patent family members in four countries.

Summary for Patent: 8,685,934

Title:	Methods for treating extreme insulin resistance in patients resistant to previous treatment with other anti-diabetic drugs employing an SGLT2 inhibitor and compositions thereof
Abstract:	The invention provides methods for treating a patient having type 2 diabetes who has failed on previous regimens of one or more oral and/or injectable anti-diabetic agents, which include the step of administering a therapeutically effective amount of an SGLT2 inhibitor alone or in combination with another anti-diabetic agent and/or other therapeutic agent to such patient. A pharmaceutical composition containing dapagliflozin or dapagliflozin-S-propylene glycol solvate and one or more diabetic agents and/or other therapeutic agents for use in the methods of the invention is also provided.
Inventor(s):	Paul Strumph, Stephanie Moran, James List
Assignee:	AstraZeneca AB
Application Number:	US13/321,103
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 8,685,934
Patent Claim Types: see list of patent claims	Use;

United States Drug Patent 8,685,934: Scope, Claims, Expiration, Litigation and Dapagliflozin Patent Landscape

U.S. Patent No. 8,685,934 protects selected methods of using an SGLT2 inhibitor, principally dapagliflozin, in patients whose glycemic control is inadequate despite insulin and/or other antidiabetic therapy. The patent is a method-of-use asset, not the primary composition-of-matter patent for dapagliflozin. Its commercial value depends on whether a competing product’s label and proposed use fall within the patient-selection, combination-therapy, dosage, and glycemic-control limitations.

The claims contain a potentially material drafting issue: the supplied version of claim 1 states that prior treatment provided inadequate glycemic control while requiring “HbA1c<7%.” An HbA1c below 7% ordinarily denotes the target level of glycemic control, not inadequate control. The issued claim language and prosecution history should control any legal analysis. The chemical structures omitted from claims 1, 5 and 9 are also necessary for a complete Markush-scope determination. The patent identifies dapagliflozin as the principal specifically claimed SGLT2 inhibitor. (USPTO, 2014; FDA, 2024a)

What does U.S. Patent 8,685,934 cover?

U.S. Patent 8,685,934 covers treatment methods for patients with type 2 diabetes or inadequate glycemic control using an SGLT2 inhibitor, including dapagliflozin, alone or with established antidiabetic agents.

Core claim architecture

Claim group	Subject matter	Principal limitation
Claims 1-4	Treatment of extreme insulin resistance	Prior insulin use of at least 50 units/day plus metformin, pioglitazone or rosiglitazone
Claims 5-7	Species and combination therapy	Dapagliflozin or dapagliflozin propylene glycol solvate with insulin and selected oral agents
Claims 8-13	Glycemic-control treatment	HbA1c target below 7% where existing therapy is inadequate
Claims 11-12	Extreme insulin resistance subset	At least 50 units/day of insulin plus ineffective background therapy

The independent claims are method claims. They require:

1. A mammalian patient.
2. Prior or ongoing treatment with specified antidiabetic therapy.
3. Inadequate glycemic control or failure to achieve the claimed HbA1c target.
4. Administration of an SGLT2 inhibitor within the claimed chemical class.
5. In certain dependent claims, combination treatment and specified dosage ranges.

The patent does not cover every use of dapagliflozin. It targets a defined treatment setting involving prior treatment failure, combination therapy, or difficult-to-control diabetes.

Which drug is identified by the patent’s chemical formula?

The specifically recited commercial compound is dapagliflozin, the active ingredient in Farxiga in the United States and Forxiga in many other markets. The claims also refer to a prodrug ester and a propylene glycol solvate, commonly described as dapagliflozin propylene glycol solvate, or dapagliflozin-PGS.

Dapagliflozin inhibits sodium-glucose cotransporter 2 in the renal proximal tubule. Its approved U.S. uses include type 2 diabetes, heart failure and chronic kidney disease indications, although the claims of U.S. 8,685,934 are directed to glycemic-control treatment in patients with inadequate control and specified background therapy. (FDA, 2024b)

What formulations are protected?

The patent’s formulation-related scope is limited. It does not appear to claim a tablet excipient system, release profile, coating, dissolution specification or manufacturing process in the claims supplied. Instead, the relevant product-form scope is:

• Dapagliflozin.
• A prodrug ester of the claimed SGLT2 inhibitor.
• A propylene glycol solvate, including dapagliflozin-PGS.
• Administration at specified daily doses, particularly 0.5 to 200 mg/day or 0.5 to 350 mg/day.

A generic tablet that contains dapagliflozin may implicate the method claims only through its use, labeling, marketing or induced conduct. The mere manufacture or sale of a composition does not automatically establish infringement of a method claim.

How do claims 1 through 13 differ?

Claims 1 through 7: extreme insulin resistance

Claim 1 is the principal extreme-insulin-resistance claim. It requires prior treatment with at least 50 insulin units per day and at least one of metformin, pioglitazone or rosiglitazone, with inadequate glycemic control.

Claim 2 adds combination treatment with one or more of:

• Insulin.
• Metformin.
• Glyburide.
• Glipizide.
• Pioglitazone.
• Rosiglitazone.
• Saxagliptin.
• Vildagliptin.
• Sitagliptin.
• Exenatide.

Claim 3 adds a dose range of approximately 0.5 to 350 mg/day.

Claim 4 narrows the combination to insulin alone or insulin with metformin and/or a thiazolidinedione.

Claim 6 specifically identifies dapagliflozin or dapagliflozin-PGS and provides dose ranges for dapagliflozin and the background therapies. The claim covers four principal regimens:

Regimen	Dapagliflozin dose	Background therapy
A	0.5-200 mg/day	Insulin
B	0.5-200 mg/day	Insulin plus metformin
C	0.5-200 mg/day	Insulin plus pioglitazone or rosiglitazone
D	0.5-200 mg/day	Insulin plus metformin plus pioglitazone or rosiglitazone

Claim 7 expands the combination alternatives to include metformin, insulin, a thiazolidinedione, or combinations of those agents.

Claims 8 through 13: inadequate glycemic control

Claim 8 is broader than claim 1 in patient-selection terms. It covers providing glycemic control below 7.0% to a patient who cannot achieve that result using insulin, metformin, pioglitazone or rosiglitazone.

Claim 11 adds extreme insulin resistance. Claim 12 defines that condition through prior treatment with at least 50 units/day of insulin and at least one of metformin, pioglitazone or rosiglitazone.

Claim 13 adds the 0.5 to 350 mg/day dose range.

The practical distinction is that claims 1-7 focus on a high-insulin-use population, while claims 8-13 focus on failure to achieve the HbA1c target. Claims 8 and 13 may have broader patient coverage but face greater exposure to prior-art and written-description challenges if the patent specification does not adequately support the full scope.

What is the likely patent expiration date?

U.S. Patent 8,685,934 was issued on April 1, 2014. Its listed patent term is generally understood to extend into 2029, based on the underlying priority and filing history. The precise effective expiration date should be taken from the current USPTO record and FDA Orange Book listing because patent term adjustment, terminal disclaimers, patent-term extension and pediatric exclusivity can affect the commercial blocking period. (USPTO, 2014; FDA, 2024a)

Event	Date or period
U.S. patent grant	April 1, 2014
Patent category	Method of treatment
Principal active ingredient	Dapagliflozin
Expected statutory term	Into 2029
U.S. regulatory product	Farxiga
NCE exclusivity for dapagliflozin	Expired before the end of the patent estate
Commercial significance	Method-of-use protection after composition-of-matter expiry

The patent is therefore separate from dapagliflozin’s original compound patent. A generic applicant may be able to challenge the compound patent while still needing to address later-expiring method, crystalline-form, formulation or combination patents listed for Farxiga.

What is the Orange Book status of U.S. Patent 8,685,934?

U.S. Patent 8,685,934 has been associated with the Farxiga patent estate as a method-of-use patent. Orange Book listings are made against approved drug products and use codes. A listing does not establish validity or infringement. It gives the patent holder a statutory basis to receive notice of an ANDA Paragraph IV certification and, if suit is filed within the statutory period, to obtain a potential 30-month stay of approval.

The relevant regulatory questions are:

• Whether the patent remains listed for the applicable Farxiga strength and indication.
• Which use code is assigned.
• Whether the generic applicant seeks the patented indication.
• Whether the ANDA uses a section viii statement to carve out the patented use.
• Whether the FDA accepts the proposed label as a valid carve-out.

For a method-of-use patent, a successful skinny-label strategy can reduce infringement risk if the carved-out label omits the patented indication and the applicant does not induce use of the patented regimen. That strategy is less effective where the patented use is inherent in the remaining label or where the manufacturer’s conduct encourages the patented use. (FDA, 2024a; 21 C.F.R. § 314.94)

What Paragraph IV challenges could affect this patent?

A Paragraph IV certification would assert that U.S. 8,685,934 is invalid, unenforceable or not infringed. The principal challenge theories would likely include the following.

Obviousness

An ANDA applicant could argue that the claimed use was obvious from:

• Prior clinical or preclinical evidence supporting SGLT2 inhibition.
• Known use of dapagliflozin for type 2 diabetes.
• Combination therapy with insulin or metformin.
• Established treatment approaches for patients failing insulin or oral agents.
• Routine dose selection within the claimed ranges.

The patent holder would rely on the selected patient population, the claimed treatment failure, the magnitude of insulin resistance and any unexpected glycemic benefit.

Indefiniteness

“Extreme insulin resistance,” “inadequate glycemic control” and “therapeutically effective amount” may receive functional interpretation, but the ≥50-unit insulin threshold provides an objective limitation in claims 1 and 12.

The supplied claim 1 language creates a more serious issue. “Inadequate glycemic control (HbA1c<7%)” is internally inconsistent under ordinary medical usage. If that language appears in the issued claim, an accused infringer could raise indefiniteness. If the source transcription contains a typographical error and the issued claim instead recites an HbA1c above 7%, the issue would not apply to the actual patent.

Written description and enablement

A challenger could argue that the specification does not support every SGLT2 inhibitor, every prodrug ester, every solvate, all combination regimens and the full 0.5 to 350 mg/day range. The species claims directed to dapagliflozin are generally less exposed than the broader genus claims.

Noninfringement

A generic applicant could argue that:

• Its label does not identify treatment of extreme insulin resistance.
• The label does not require prior treatment with at least 50 units/day of insulin.
• The product is indicated for a different condition.
• The proposed use does not require the claimed combinations.
• The dose or patient population falls outside the claim.

Which companies are challenging dapagliflozin exclusivity?

Dapagliflozin has attracted ANDA activity because Farxiga is a high-value product with several overlapping patents. The principal risk does not come from U.S. 8,685,934 alone. It comes from the combined estate covering the active compound, crystalline forms, formulations, methods and combination products.

Publicly reported ANDA litigation and patent challenges involving dapagliflozin have included generic manufacturers such as Mylan, Sun Pharmaceutical, Zydus and other applicants, depending on the product, strength and patent set at issue. The exact defendant and asserted-patent mix varies by case and filing year. A litigation docket must be reviewed patent by patent because a challenge to the compound or crystalline-form patent does not necessarily invalidate U.S. 8,685,934.

No conclusion that a particular generic manufacturer has defeated this patent should be drawn solely from the existence of an ANDA challenge. A Paragraph IV notice is an allegation, not a judgment.

How does U.S. 8,685,934 compare with other Farxiga patents?

Patent category	Typical protection	Commercial role
Compound patent	Dapagliflozin chemical structure	Foundational protection
Solid-form patent	Crystalline dapagliflozin or solvate	Product-quality and substitution barrier
Method patent	Treatment of difficult-to-control diabetes	Use-specific blocking right
Combination patent	Dapagliflozin with insulin or other agents	Regimen protection
Formulation patent	Tablet composition or delivery system	Product-specific protection
Manufacturing patent	Synthesis, purification or crystallization	Process and supply-chain barrier

U.S. 8,685,934 is strongest where the branded label, prescribing information and clinical use specifically target patients who remain uncontrolled despite high-dose insulin and background therapy. It is weaker against a generic label that omits those uses and against off-label use that cannot be tied to the manufacturer’s instructions or promotional conduct.

The patent does not independently prevent all dapagliflozin competition. Its value is cumulative. A generic may need to overcome the remaining Orange Book patents even if it establishes that 8,685,934 is invalid or not infringed.

What litigation and settlement issues affect generic launch timing?

A branded company can trigger the Hatch-Waxman 30-month stay by filing an infringement action within 45 days after receiving a Paragraph IV notice for a listed patent. The stay may be shortened or terminated by court action, settlement, patent expiration or other statutory events. (Hatch-Waxman Act, 1984)

Settlement agreements may include:

• An agreed generic entry date.
• A license before patent expiration.
• Restrictions tied to specific indications.
• No-AG or authorized-generic provisions.
• Covenants concerning formulation or manufacturing patents.
• Allocation of launch rights among multiple generic applicants.

The existence of a settlement does not necessarily resolve the commercial risk created by U.S. 8,685,934. A settlement may cover only one patent, one strength or one indication.

How strong is the patent estate for dapagliflozin?

The estate is commercially significant but structurally mixed.

Stronger elements

• Specific dapagliflozin species claims.
• Objective ≥50-units/day insulin limitation.
• Claims directed to defined combination regimens.
• Patent position tied to an FDA-approved use code.
• Potential inducement exposure if a generic label retains the patented use.

Weaker elements

• Broad SGLT2-inhibitor genus claims.
• Functional terms such as “inadequate glycemic control.”
• Broad dose ranges extending well beyond ordinary approved doses.
• Potentially inconsistent HbA1c language in the supplied claim text.
• Dependence on patient behavior and physician prescribing.
• Reduced value if the patented use can be removed through a valid section viii carve-out.

The issued claim construction, prosecution history, Orange Book use code and generic label are decisive. The claim text supplied by the requester is insufficient to establish the final scope of the omitted chemical formula or to confirm whether the HbA1c limitation is accurately transcribed.

What generic launch scenarios exist?

Scenario 1: full-label launch after patent litigation

A generic applicant defeats or avoids all blocking patents and launches with the principal diabetes indication. This creates the highest revenue exposure for Farxiga.

Scenario 2: skinny-label launch

The applicant removes the patented extreme-insulin-resistance or combination-treatment use. The product launches for non-patented indications, subject to other patents and induced-infringement risk.

Scenario 3: licensed entry

The applicant settles with the patent holder and enters on an agreed date. The commercial effect depends on whether the settlement permits multiple generic entrants or grants an exclusive first-entry position.

Scenario 4: at-risk launch

The applicant launches before final resolution, accepting potential damages and injunction exposure. This is less attractive where multiple patents remain enforceable.

What geographic coverage does U.S. 8,685,934 provide?

U.S. 8,685,934 provides protection only in the United States. Corresponding international family members may exist, but each jurisdiction has independent claim scope, validity standards, term rules and litigation outcomes.

The patent does not automatically protect dapagliflozin methods in Europe, Canada, Japan, China or other markets. International commercial analysis requires separate review of:

• National-phase patents.
• Supplementary protection certificates in Europe.
• Local use claims.
• Product and formulation patents.
• Local regulatory data exclusivity.
• National settlement agreements.

What revenue exposure is linked to this patent?

The patent’s revenue exposure is indirect because it protects a method of use rather than the entire Farxiga product. Its economic value depends on the proportion of prescriptions involving:

• Patients using at least 50 units/day of insulin.
• Patients receiving insulin plus metformin.
• Patients receiving insulin plus a thiazolidinedione.
• Patients whose HbA1c remains above the relevant control threshold.
• Prescriptions supported by a label or promotional statement that maps to the claims.

Farxiga revenue also includes heart-failure and chronic-kidney-disease uses. Those indications may not fall within the supplied claims, which are centered on glycemic control. Accordingly, invalidation or expiration of U.S. 8,685,934 would not necessarily eliminate all branded revenue if other patents or approved indications remain protected.

Key Takeaways

• U.S. Patent 8,685,934 is a dapagliflozin method-of-use patent.
• Its core population is patients with inadequate glycemic control despite insulin and/or selected oral antidiabetic agents.
• Claims 1-7 focus on extreme insulin resistance, including prior insulin use of at least 50 units/day.
• Claims 8-13 address achieving HbA1c below 7% after failure of conventional therapy.
• Claims 6 and 10 specifically target dapagliflozin or dapagliflozin-PGS in combination with insulin, metformin and/or a thiazolidinedione.
• The patent is expected to run into 2029, subject to the controlling USPTO and Orange Book term data.
• Paragraph IV risk centers on obviousness, indefiniteness, written description, enablement, noninfringement and label-carve-out arguments.
• The supplied claim 1 contains a material HbA1c inconsistency if “HbA1c<7%” is the actual issued language.
• Generic entry risk must be assessed against the entire Farxiga estate, not this patent in isolation.
• A skinny-label launch may reduce exposure if the patented use can be validly carved out.

FAQs

Does U.S. Patent 8,685,934 cover all dapagliflozin products?

No. It covers specified methods of using an SGLT2 inhibitor, particularly dapagliflozin, in defined treatment populations and combinations.

Can a generic sell dapagliflozin after this patent expires?

Potentially, but other Farxiga patents, regulatory exclusivities, litigation outcomes and product-specific barriers may still affect launch timing.

Does a 50-unit insulin threshold appear in every claim?

No. The threshold is central to claims 1 and 12 and affects dependent claim scope, but claims 8-10 and 13 use broader inadequate-control language.

Is dapagliflozin-PGS the same as dapagliflozin?

Dapagliflozin-PGS is a propylene glycol solvate form of dapagliflozin. The active pharmaceutical ingredient delivered after administration is dapagliflozin, but solid-form and solvate distinctions can matter for patent infringement and regulatory filings.

Can a generic avoid infringement by removing the extreme-insulin-resistance indication?

Possibly. A valid section viii carve-out may reduce method-of-use infringement risk, but the proposed label, promotional conduct, remaining indications and other Farxiga patents must be evaluated together.

References

1. U.S. Food and Drug Administration. (2024a). Approved drug products with therapeutic equivalence evaluations: Orange Book.
2. U.S. Food and Drug Administration. (2024b). Farxiga (dapagliflozin) prescribing information. AstraZeneca Pharmaceuticals LP.
3. U.S. Patent and Trademark Office. (2014). U.S. Patent No. 8,685,934, Methods of treating diabetes mellitus.
4. Code of Federal Regulations. (2024). 21 C.F.R. § 314.94: Content and format of an abbreviated new drug application.
5. Drug Price Competition and Patent Term Restoration Act of 1984, Pub. L. No. 98-417, 98 Stat. 1585.

Drugs Protected by US Patent 8,685,934

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Astrazeneca Ab	XIGDUO XR	dapagliflozin; metformin hydrochloride	TABLET, EXTENDED RELEASE;ORAL	205649-005	Jul 28, 2017	AB	RX	Yes	No					Y
Astrazeneca Ab	XIGDUO XR	dapagliflozin; metformin hydrochloride	TABLET, EXTENDED RELEASE;ORAL	205649-002	Oct 29, 2014	AB	RX	Yes	No					Y
Astrazeneca Ab	XIGDUO XR	dapagliflozin; metformin hydrochloride	TABLET, EXTENDED RELEASE;ORAL	205649-001	Oct 29, 2014	AB	RX	Yes	No					Y

Foreign Priority and PCT Information for Patent: 8,685,934

PCT Information
PCT Filed	May 26, 2010	PCT Application Number:	PCT/US2010/036120
PCT Publication Date:	December 02, 2010	PCT Publication Number:	WO2010/138535

International Family Members for US Patent 8,685,934

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
China	102639125
China	106075451
European Patent Office	2435033