Details for Patent: 7,951,400

Which drugs does patent 7,951,400 protect, and when does it expire?

Patent 7,951,400 protects ONGLYZA and is included in one NDA.

This patent has fifty-seven patent family members in thirty-two countries.

Summary for Patent: 7,951,400

Title:	Coated tablet formulation and method
Abstract:	A coated tablet formulation is provided which includes a medicament such as the DPP4-inhibitor, saxagliptin or its HCl salt, which is subject to intra-molecular cyclization, which formulation includes a tablet core containing one or more fillers, and other conventional excipients, which tablet core includes a coating thereon which may include two or more layers, at least one layer of which is an inner seal coat layer which is formed of one or more coating polymers, a second layer of which is formed of medicament which is the DPP4-inhibitor and one or more coating polymers, and an optional, but preferable third outer protective layer which is formed of one or more coating polymers. A method for forming the coated tablet is also provided.
Inventor(s):	Divyakant S. Desai, Bing V. Li
Assignee:	AstraZeneca AB
Application Number:	US11/137,068
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 7,951,400
Patent Claim Types: see list of patent claims	Composition; Formulation; Compound; Dosage form;

United States Patent 7,951,400: Saxagliptin Coated-Tablet Claims, Scope, Expiry and Generic Risk

U.S. Patent No. 7,951,400 protects specific multilayer coated-tablet architectures containing saxagliptin, particularly saxagliptin hydrochloride. It does not claim saxagliptin as a molecule, diabetes treatment generally, or every saxagliptin tablet. The central requirement is a tablet core with a polyvinyl-alcohol-based inner seal coating, a saxagliptin-containing second coating, and, in the broadest independent claim, an outer protective polyvinyl-alcohol-based coating.

The patent is formulation-specific. A generic product can avoid literal infringement by using a different dosage-form architecture, such as a conventional compressed matrix tablet, a single film coat, a non-polyvinyl-alcohol coating system, or a saxagliptin-containing layer that does not satisfy the claimed quantitative and structural limitations. The main legal risk is highest for a product that reproduces the patented layered coating process and the excipient system described in claims 6 through 10.

What does U.S. Patent 7,951,400 cover?

U.S. Patent 7,951,400 covers coated tablets in which saxagliptin is incorporated into a coating layer rather than merely being blended into the tablet core. The patent identifies a three-layer coating arrangement:

1. A tablet core.
2. An inner seal coating containing a polyvinyl alcohol-based formulation.
3. A second coating containing saxagliptin and a polyvinyl alcohol-based formulation.
4. An outer protective coating containing a polyvinyl alcohol-based formulation.

The patent is assigned to Bristol-Myers Squibb Company and relates to the commercial formulation technology associated with saxagliptin products such as Onglyza. The disclosed formulation uses common tableting excipients, including lactose monohydrate, microcrystalline cellulose, croscarmellose sodium and magnesium stearate. The coating system uses polyvinyl alcohol, polyethylene glycol, talc and titanium dioxide. [1]

The claims are composition claims. They do not expressly require a particular dissolution profile, manufacturing equipment, coating temperature, spray rate or therapeutic indication.

How broad is claim 1 of Patent 7,951,400?

Claim 1 is the principal broad claim. It requires all of the following elements:

Claim element	Required limitation
Dosage form	Coated tablet
Core	Tablet core
First coating	Inner seal coating on the core
Inner coating composition	About 1 mg to about 100 mg of a polyvinyl alcohol-based formulation comprising polyvinyl alcohol
Drug-containing layer	Second coating on the inner seal coating
Active ingredient	About 0.2 mg to about 140 mg of saxagliptin or a pharmaceutically acceptable salt
Second coating excipient	About 2 mg to about 140 mg of a polyvinyl alcohol-based formulation comprising polyvinyl alcohol
Outer layer	Outer protective coating on the second coating
Outer coating composition	About 1 mg to about 100 mg of a polyvinyl alcohol-based formulation comprising polyvinyl alcohol

A product must satisfy the full combination to infringe claim 1 literally. Omitting the outer protective coating, using a different active pharmaceutical ingredient, or placing saxagliptin in the core rather than the second coating would create a substantial noninfringement position under the claim language.

The terms “about” create numerical flexibility but do not eliminate the need to fall within the claimed composition. Courts generally assess “about” in view of the patent’s specification, prosecution history and technical context. A formulation near a numerical boundary may present a fact-intensive infringement dispute.

What do claims 2 through 5 add?

Claims 2 through 5 narrow claim 1 by adding core-composition, formulation-range or strength-specific limitations.

Claim 2: core excipients

Claim 2 requires the tablet core to contain one or more fillers, with optional binders, disintegrants and tableting lubricants. This claim is broad within the context of claim 1 because it does not require a particular filler or a fixed percentage.

Claim 3: specified core composition

Claim 3 requires:

• Microcrystalline cellulose
• Lactose monohydrate
• Croscarmellose sodium
• Magnesium stearate

This combination corresponds closely to a conventional direct-compression or dry-granulated tablet core. A generic product using the same four ingredients could satisfy claim 3 if it also satisfies every limitation inherited from claim 1.

Claim 4: quantitative formulation ranges

Claim 4 specifies a 200 mg tablet core and percentage ranges for the core and coating layers. The disclosed ranges include:

Component	Claimed or disclosed range
Lactose	20% to 75% of core, or 40 mg to 150 mg
Microcrystalline cellulose	20% to 75% of core, or 40 mg to 150 mg
Croscarmellose sodium	2% to 10% of core, or 4 mg to 20 mg
Magnesium stearate	0.2% to 2% of core, or 0.4 mg to 4 mg
Inner PVA coating	1% to 3%, or 2 mg to 6 mg
Second PVA coating	0.25% to 70%, or 0.5 mg to 140 mg
Saxagliptin-containing portion	1% to 50%, or 2 mg to 100 mg
Outer protective coating	1% to 5%, or 2 mg to 10 mg

Claim 4 contains drafting issues in the reproduced text, including inconsistent headings and apparent typographical errors such as “plazticizer.” The issued patent, prosecution history and claim-construction record control over a transcription of the claims. The quantitative ranges should therefore be analyzed against the issued patent text rather than an OCR or database copy.

Claim 5: 5 mg and 2.5 mg strengths

Claim 5 targets two dosage configurations:

• 5 mg potency: 5 mg saxagliptin and at least 5 mg polyvinyl-alcohol-based formulation in the second coating.
• 2.5 mg potency: 2.5 mg saxagliptin and 20 mg polyvinyl-alcohol-based formulation in the second coating.

This claim is commercially important because it maps directly onto low-strength saxagliptin tablets. A generic applicant using a different coating-to-drug ratio may avoid claim 5 while remaining exposed to broader claim 1 or narrower claims 6 through 10.

What do claims 6 through 10 protect?

Claims 6 through 10 define a more specific excipient formulation.

Claim 6: defined core and coating system

Claim 6 requires a tablet core containing approximately:

• 49.5% lactose monohydrate
• 45% microcrystalline cellulose
• 5% croscarmellose sodium
• 0.5% magnesium stearate

The inner seal coating must contain approximately:

• 40% polyvinyl alcohol
• 20% polyethylene glycol
• 15% talc
• 25% titanium dioxide

The saxagliptin-containing second coating must contain saxagliptin or a pharmaceutically acceptable salt together with the same general coating-material system. The outer protective coating is optional under claim 6.

Claim 7: second coating composition

Claim 7 narrows claim 6 by requiring the second coating to contain saxagliptin and a coating material comprising approximately 40% polyvinyl alcohol, 20% polyethylene glycol, 15% talc and 25% titanium dioxide.

Claim 8: outer coating composition

Claim 8 requires the outer protective coating to contain the same approximate 40/20/15/25 composition.

Claims 9 and 10: hydrochloride salt

Claims 9 and 10 specify saxagliptin hydrochloride. These claims are narrower than claims covering saxagliptin generally, but they are commercially relevant because saxagliptin hydrochloride is the active form used in the marketed product.

What products may fall within the patent claims?

A product is most likely to fall within the asserted claims if it has the following characteristics:

Product characteristic	Patent risk
Saxagliptin hydrochloride in a discrete coating layer	High
Inner PVA seal coat and outer PVA protective coat	High
PVA/PEG/talc/titanium dioxide coating system	High under claims 6-10
Lactose/MCC/croscarmellose/magnesium stearate core	Increases risk under claims 3, 6 and 7
Saxagliptin blended only into the tablet core	Lower literal risk
Single conventional film coat	Lower literal risk
Hydroxypropyl methylcellulose replacing PVA	Lower literal risk, subject to equivalents
No separate inner seal coating	Lower literal risk
No outer protective coating	Avoids claim 1 but may require analysis of claims 6 and related claim scope
Saxagliptin oral solution, capsule or injectable	Outside the claimed tablet form

The doctrine of equivalents could create risk where a substitute coating performs substantially the same function in substantially the same way to obtain substantially the same result. Prosecution-history estoppel may limit that argument if the applicant narrowed the claims to obtain allowance.

When does Patent 7,951,400 expire?

The patent issued on May 31, 2011. Its relevant application has a February 1, 2007 filing date and claims priority to February 1, 2006. The standard twenty-year patent term is therefore expected to run to February 1, 2027, subject to any patent-term adjustment, terminal disclaimer or other term calculation reflected in USPTO and FDA records. [1,2]

Milestone	Date
Earliest stated priority	February 1, 2006
U.S. application filing	February 1, 2007
Patent issuance	May 31, 2011
Expected standard expiration	February 1, 2027
FDA approval of Onglyza	July 31, 2009
New chemical entity exclusivity	Expired in 2014

The patent is separate from FDA regulatory exclusivity. FDA approval exclusivity does not extend the patent term. Conversely, an unexpired formulation patent can delay an ANDA launch if the patent is listed in the Orange Book and survives challenge.

What is the Orange Book status of U.S. Patent 7,951,400?

Patent 7,951,400 has been associated with the Onglyza saxagliptin product patent estate and should be evaluated through the FDA Orange Book patent-listing data for the relevant product and dosage forms. The Orange Book determines whether the patent is formally listed against a particular reference-listed drug and whether an ANDA applicant must submit a Paragraph IV certification. [3]

The legal significance depends on:

• The specific reference-listed drug.
• The dosage form and strength.
• Whether the patent is listed for Onglyza, a combination product, or another saxagliptin product.
• Whether the listing remains active.
• Whether FDA has recorded an expiration-date change or delisting.

A formulation patent generally has a narrower Orange Book reach than a compound patent. Listing does not establish validity or infringement. It creates a regulatory certification pathway under the Hatch-Waxman Act.

How does the patent compare with saxagliptin compound patents?

The principal distinction is between molecule protection and dosage-form protection.

Patent category	Protection	Commercial effect
Compound patent	Saxagliptin chemical structure and related compounds	Broadest product protection
Salt or solid-state patent	Saxagliptin hydrochloride, polymorph or crystalline form	Controls specific active form
Formulation patent 7,951,400	Multilayer coated tablet with PVA-based coatings	Controls a particular dosage-form design
Method-of-use patent	Treatment of diabetes or related indications	Relevant to labeling and skinny-label strategy
Manufacturing patent	Synthesis, purification or crystallization	May create process risk without blocking all finished-product manufacture

U.S. Patent 7,951,400 does not replace the compound patent. A generic applicant may face compound, salt, formulation, method-of-use and manufacturing patents at the same time. The practical launch date is determined by the last enforceable barrier that covers the proposed product or its labeling.

What Paragraph IV challenges could affect this patent?

An ANDA applicant seeking approval before expiration may certify that the patent is invalid, unenforceable or will not be infringed under Paragraph IV of the Hatch-Waxman Act. A challenge to Patent 7,951,400 would likely focus on four issues.

Anticipation

The challenger would seek an earlier reference disclosing the complete combination of:

• A tablet core.
• An inner PVA seal coating.
• A saxagliptin-containing second coating.
• The required coating quantities.
• An outer protective PVA coating, where required.

A reference disclosing saxagliptin tablets without the claimed layered architecture would not anticipate claim 1.

Obviousness

Obviousness is likely to be the principal validity issue. A challenger could combine prior art on saxagliptin tablets with prior art on PVA film coatings and multilayer pharmaceutical coatings. The patent holder would argue that the specific drug-in-coating configuration, layer order, coating quantities and stability characteristics were not predictable from the cited references.

Written description and enablement

The broad numerical ranges in claim 1 could attract scrutiny if the specification does not support the full range of saxagliptin quantities and coating weights. Claims 6 through 10 are less vulnerable on breadth because they recite a defined excipient system and approximate percentages.

Infringement by design-around

A generic applicant may use a Paragraph IV position based on noninfringement rather than invalidity. The most direct design-around is to place saxagliptin in the tablet core and apply a conventional single film coat. Another approach is to remove the separate inner seal layer or replace PVA with another film-forming polymer.

What generic entry risks exist for saxagliptin?

Saxagliptin is a small-molecule drug, so the relevant pathway is an ANDA, not a biosimilar application. FDA approval requires pharmaceutical equivalence and bioequivalence to the reference product. A generic applicant does not need to reproduce the patented formulation if it can demonstrate equivalence using a noninfringing formulation.

The risk profile is therefore formulation-sensitive:

Generic strategy	Likely patent exposure
Reproduce Onglyza multilayer coated tablet	High
Use saxagliptin in a conventional tablet core	Lower formulation-patent exposure
Use a different film-forming polymer	Lower literal infringement risk
Use a different salt or solid form	May trigger separate salt or solid-state patents
Use a different label	May reduce method-of-use exposure
Launch after patent expiry	Eliminates ordinary prospective infringement risk under the expired patent

A Paragraph IV notice can trigger a 30-month FDA approval stay if the patent holder files a timely infringement action. The stay applies through the Hatch-Waxman framework and does not itself establish patent validity. [4]

Are biosimilars relevant to Patent 7,951,400?

No. Saxagliptin is a chemically synthesized small molecule, not a biologic. Biosimilar approval under the Public Health Service Act is not the relevant pathway. Competitive entry would normally proceed through an ANDA or, depending on the product and formulation, an alternative FDA application. The patent’s commercial significance is therefore tied to generic tablets, not biosimilar products.

What litigation and settlement issues affect the patent?

The principal litigation risk would arise from an ANDA Paragraph IV challenge directed to Onglyza or another saxagliptin reference product. The relevant record should be separated into:

1. Litigation involving the compound patent.
2. Litigation involving formulation patent 7,951,400.
3. Litigation involving combination products such as saxagliptin/metformin.
4. Patent disputes involving salt, polymorph or manufacturing patents.

A settlement may provide an authorized-generic date, an agreed launch date, a covenant not to sue, or other commercial terms. Public patent records do not convert a listed patent into a proven litigation barrier. A business assessment should rely on the FDA Orange Book, USPTO Patent Center, federal court docket and any publicly filed settlement documents. [2,3,5]

How strong is the patent estate for the claimed formulation?

The formulation estate is stronger against literal copies than against products designed around the coating architecture.

Strengths

• The independent claim identifies a distinctive layer sequence.
• Claims 6 through 10 recite a detailed excipient system.
• The claims cover saxagliptin hydrochloride specifically.
• The claims can reach a product even if the tablet core is conventional, provided the drug is placed in the claimed coating layer.
• The patent is directed to a finished dosage form, making process-independent product analysis possible.

Weaknesses

• The claims depend on multiple structural and quantitative limitations.
• A generic developer can shift saxagliptin from the coating into the core.
• PVA is not the only pharmaceutical film-forming polymer.
• Claims using “about” and broad coating-weight ranges may generate claim-construction disputes.
• The patent does not broadly cover all oral saxagliptin dosage forms.
• Validity may depend on whether prior art disclosed multilayer coatings and the use of PVA systems with comparable drugs.

The patent is best characterized as a moderate-to-strong barrier against direct formulation copying and a weaker barrier against noninfringing generic redesign.

What manufacturing and geographic barriers remain?

The patent is territorial. U.S. Patent 7,951,400 affects manufacture, use, sale, offer for sale and importation involving the United States during the enforceable term. It does not independently block manufacture and sale in countries where no corresponding patent exists or where the corresponding patent has expired.

Manufacturing risk remains relevant even when the final tablet is produced outside the United States. Importing an infringing finished tablet into the United States can create liability. A process conducted abroad may also create U.S. exposure if it results in an imported product that practices the patent or if separate U.S. process patents apply.

A full geographic review should identify the foreign family members, national-phase status, local expiration dates, oppositions, lapse events and supplementary protection certificates. The U.S. patent alone cannot establish worldwide exclusivity. [1,2]

What is the revenue exposure from Patent 7,951,400?

Patent 7,951,400 protects a formulation associated with a branded saxagliptin product, but its revenue impact is narrower than that of the core compound patent. Its economic value depends on whether:

• The formulation is required by the reference product.
• Generic applicants can design around the layer structure.
• The Orange Book listing applies to the relevant dosage form.
• Other patents expire earlier or later.
• The market includes combination products with separate patent estates.
• An authorized generic or settlement accelerates entry.

The patent could support litigation leverage and delay a copycat formulation, but it may not prevent all generic saxagliptin tablets. A revenue model should treat the patent as one component of the launch-barrier stack rather than as a standalone block on generic entry.

Key Takeaways

• U.S. Patent 7,951,400 is a formulation patent for multilayer saxagliptin coated tablets.
• Claim 1 requires an inner PVA seal coating, a saxagliptin-containing PVA-based second coating and an outer PVA protective coating.
• Claims 6 through 10 narrow the scope to a specific lactose/MCC tablet core and PVA/PEG/talc/titanium dioxide coating system.
• Claims 9 and 10 specifically cover saxagliptin hydrochloride.
• The expected standard expiration date is February 1, 2027, subject to the official term calculation.
• The patent does not cover saxagliptin as a molecule or every saxagliptin dosage form.
• The principal generic design-around is to place saxagliptin in the tablet core or use a non-PVA, single-layer coating.
• Saxagliptin is a small molecule, so biosimilar law is not relevant.
• Orange Book listing, Paragraph IV litigation and any settlement must be assessed against the specific reference-listed drug and dosage form.
• The patent is a meaningful barrier to formulation copying but a less complete barrier to generic saxagliptin entry.

FAQs About U.S. Patent 7,951,400

Does Patent 7,951,400 cover Onglyza 5 mg?

It may cover a 5 mg Onglyza tablet if the product satisfies the claimed multilayer structure, PVA-based coating requirements and quantitative limitations. Product-level infringement requires analysis of the approved formulation and the issued claims.

Does the patent cover saxagliptin tablets made without a coating?

No. The asserted claims require a coated tablet and specific coating layers. A non-coated tablet would not literally satisfy those limitations.

Can a generic use saxagliptin hydrochloride after changing the coating polymer?

Potentially. Replacing PVA may avoid literal infringement, but the complete formulation and the doctrine of equivalents must be evaluated against each asserted claim.

Is Patent 7,951,400 a compound patent?

No. It is a dosage-form and formulation patent. The patent does not claim the saxagliptin chemical structure broadly.

Does expiration of Patent 7,951,400 guarantee immediate generic launch?

No. Other listed patents, regulatory exclusivity, litigation stays, settlements, salt or solid-state patents, method-of-use claims and product-specific approval requirements may affect launch timing.

References

1. U.S. Patent and Trademark Office. (2011). U.S. Patent No. 7,951,400, Coated tablets comprising saxagliptin.
2. U.S. Patent and Trademark Office. (n.d.). Patent Center: U.S. Patent No. 7,951,400.
3. U.S. Food and Drug Administration. (n.d.). Orange Book: Approved drug products with therapeutic equivalence evaluations.
4. Drug Price Competition and Patent Term Restoration Act of 1984, 21 U.S.C. § 355(j).
5. U.S. Courts. (n.d.). Public Access to Court Electronic Records (PACER).

Drugs Protected by US Patent 7,951,400

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	ONGLYZA	saxagliptin hydrochloride	TABLET;ORAL	022350-001	Jul 31, 2009		DISCN	Yes	No	7,951,400		Y
Astrazeneca Ab	ONGLYZA	saxagliptin hydrochloride	TABLET;ORAL	022350-002	Jul 31, 2009		DISCN	Yes	No	7,951,400		Y

International Family Members for US Patent 7,951,400

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	049062
Argentina	099567
Australia	2005249467
Brazil	PI0510419
Canada	2568391
China	102895208