US Patent 8,088,786: Scope, Claims, Expiration, and Contrave Patent Landscape

US Patent 8,088,786 protects a bilayer pharmaceutical tablet combining sustained-release naltrexone and sustained-release bupropion. Its central limitation is physical separation of the two drug layers by a rapidly dissolving sugar layer, while preserving the independent dissolution profiles of each active ingredient. The patent is directly relevant to Contrave, the naltrexone/bupropion extended-release product marketed in the United States.

The patent’s commercial significance is concentrated in its formulation architecture, not in the general therapeutic use of naltrexone and bupropion together. A product that uses the claimed bilayer structure, dosage ranges, rapidly dissolving intermediate layer, and dissolution characteristics could face infringement risk even if it uses different excipients or manufacturing equipment.

What drug and formulation does US Patent 8,088,786 protect?

US 8,088,786, titled “Layered Pharmaceutical Formulation,” was assigned during prosecution to Orexigen Therapeutics, Inc. The patent covers a multilayer tablet containing:

Element	Claim requirement
First active layer	About 2 mg to about 35 mg sustained-release naltrexone
Second active layer	About 50 mg to about 200 mg sustained-release bupropion
Intermediate layer	Monosaccharide or disaccharide sugar
Layer function	Rapid dissolution in vivo
Physical effect	Naltrexone and bupropion layers remain substantially intact but separate
Dissolution requirement	Each active ingredient retains a profile substantially equivalent to its corresponding single compressed tablet
Dependent timing limitation	The layers separate in vivo in less than one minute

Contrave contains 8 mg of extended-release naltrexone and 90 mg of extended-release bupropion per tablet. Those amounts fall within the narrower ranges of claims 3 and 5, respectively. The FDA-approved label identifies Contrave as an extended-release tablet containing 8 mg naltrexone hydrochloride and 90 mg bupropion hydrochloride per tablet.[2]

How broad is independent claim 1?

Claim 1 is a product claim with structural and functional limitations. It does not cover every combination tablet containing naltrexone and bupropion. The accused product must satisfy each material limitation.

The claim has five principal scope components:

A first pharmaceutical layer containing sustained-release naltrexone.
A second pharmaceutical layer containing sustained-release bupropion.
An intermediate sugar layer between the two active layers.
Rapid in-vivo dissolution of the intermediate layer, leaving the active layers substantially intact and physically separated.
Independent dissolution behavior corresponding to the two active layers when tested as separate compressed tablets.

The claim does not expressly require lactose. Lactose is added by dependent claim 2. Nor does claim 1 require a separation time of less than one minute. That limitation appears only in claim 6.

The claim therefore reaches a broader class of bilayer tablets than the specific lactose-containing, 8 mg/90 mg, sub-one-minute Contrave configuration. A competing formulation could avoid claims 2, 3, 5, or 6 while still presenting risk under claim 1.

What does “substantially the same dissolution profile” mean?

The phrase “substantially the same” is a central infringement and validity issue. The claim compares:

The naltrexone layer in the bilayer formulation with a single compressed naltrexone tablet of the same size and shape.
The bupropion layer in the bilayer formulation with a single compressed bupropion tablet having the same composition, size, and shape.

This language attempts to prevent the intermediate sugar layer from materially altering the release characteristics of either active ingredient. It also creates factual complexity because infringement may depend on dissolution protocols, sampling intervals, pH conditions, agitation, specifications, and acceptable variability.

A generic manufacturer could dispute whether its tablet has a dissolution profile that is “substantially the same,” particularly if the product uses a different release matrix, coating, compression force, particle-size distribution, or dissolution method. The patent holder would likely rely on comparative dissolution testing and formulation-development records.

What do claims 2 through 6 add?

Claim	Additional limitation	Commercial effect
2	Intermediate layer contains lactose	Targets a common and commercially relevant sugar-layer formulation
3	Naltrexone amount is about 4 mg to about 10 mg	Encompasses the 8 mg Contrave dose
4	Bupropion amount is about 75 mg to about 150 mg	Encompasses the 90 mg Contrave dose
5	Bupropion amount is about 85 mg to about 100 mg	More closely tracks the 90 mg commercial dose
6	Active layers separate in vivo in less than one minute	Adds a measurable performance limitation

Claims 3 and 5 are particularly relevant to Contrave because the marketed product contains 8 mg naltrexone and 90 mg bupropion per tablet. Claim 6 may be difficult to establish without validated testing that demonstrates the claimed in-vivo separation time. The specification and prosecution history would be important in determining whether “in vivo” permits an in-vitro disintegration or dissolution surrogate.

When does US Patent 8,088,786 expire?

The patent’s nominal US patent term is tied to the relevant international or nonprovisional filing date rather than the January 3, 2012 grant date. Public patent records identify the relevant filing history as beginning in 2008, with priority claims reaching back to 2007.[1]

The expected base term is in the 2028 period, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and the specific USPTO term calculation. The grant date does not establish the expiration date. A commercial freedom-to-operate analysis should use the USPTO Patent Examination Data System or Patent Center term calculation and the FDA Orange Book listing, not a simple 20-year calculation from the issue date.

Event	Date or period
Priority period	2007
International or nonprovisional filing period	2008
Patent grant	January 3, 2012
Contrave FDA approval	September 10, 2014
Expected base patent term	2028 period, subject to adjustment
Regulatory exclusivity	Separate from patent term and largely expired

Patent expiration and Orange Book listing are separate questions. A patent can remain unexpired but have no Orange Book listing for a particular product, while an Orange Book-listed patent can create an ANDA certification and litigation pathway.

What is the FDA and Orange Book status of the patent?

Contrave received FDA approval under the new drug application pathway in 2014. The product is not a biologic, so biosimilar procedures do not apply. A generic applicant would ordinarily pursue an ANDA and address listed patents through paragraph I, II, III, or IV certifications under the Hatch-Waxman framework.[3]

The key regulatory issues are:

Whether US 8,088,786 is listed in the Orange Book for Contrave.
Whether the listing covers the approved strength and dosage form.
Whether the listing remains active on the relevant submission date.
Whether the applicant makes a paragraph IV certification.
Whether the patent holder files suit within 45 days of receiving notice.

An Orange Book listing can trigger a 30-month stay of ANDA approval if the patent holder timely files an infringement action after receiving a paragraph IV notice. That stay does not automatically extend the patent term and can be shortened or removed through litigation or regulatory action.

The product’s new chemical entity exclusivity and any pediatric exclusivity are distinct from the formulation patent. FDA approval in 2014 means the original regulatory exclusivity periods have expired. Current generic entry risk therefore turns primarily on remaining patent claims, litigation settlements, regulatory review, and commercial launch decisions.[2][3]

Which formulation features create the principal infringement risk?

The highest-risk configuration is a tablet that has all of the following characteristics:

8 mg extended-release naltrexone;
90 mg extended-release bupropion;
two physically distinct active layers;
a dissolvable sugar layer between the active layers;
dissolution behavior substantially matching separate single-layer tablets; and
rapid in-vivo or validated surrogate separation.

A formulation using lactose as the intermediate layer presents a direct claim 2 issue. A formulation with 4 mg to 10 mg naltrexone and 85 mg to 100 mg bupropion presents a direct claim 3 and claim 5 issue. A product with different dosages may avoid narrower dependent claims but still fall within claim 1’s broader ranges.

A monolithic matrix tablet, capsule containing separate granules, physically separated beads, or bilayer tablet using a non-sugar barrier may present lower literal infringement risk. Those designs could still face a doctrine-of-equivalents theory, depending on whether the substitute barrier performs substantially the same function in substantially the same way to achieve substantially the same result.

How strong is the patent estate?

US 8,088,786 has meaningful commercial strength because the claims are tied to a distinctive delivery architecture and correspond closely to the marketed 8 mg/90 mg product. Its main strengths are:

direct coverage of the combination product’s dosage ranges;
separate layers for the two extended-release actives;
a functional requirement preserving individual dissolution profiles;
dependent claims closely aligned with the commercial strength; and
potential Orange Book relevance for ANDA applicants.

The main vulnerabilities are claim-construction and proof issues:

“sustained-release” may require interpretation from the specification;
“substantially the same” may be challenged as indefinite or difficult to apply;
“rapidly dissolve” lacks a fixed time limit in claim 1;
“substantially intact” may require technical evidence;
“in vivo” separation under claim 6 may be difficult to reproduce; and
prior-art combinations involving bilayer tablets, sugar barriers, and independently released actives could support obviousness arguments.

The patent is stronger against a product intentionally designed to replicate the Contrave bilayer structure than against a materially different dosage form.

What patent litigation and paragraph IV risks affect Contrave?

A generic applicant challenging Contrave would likely target the patent through a paragraph IV certification, asserting that the claims are invalid, unenforceable, or not infringed. The likely technical defenses would focus on:

Lack of novelty or obviousness based on prior bilayer and multilayer tablets.
Failure to satisfy the dissolution-profile limitations.
Absence of a monosaccharide or disaccharide intermediate layer.
Lack of sustained-release characteristics in one or both layers.
Non-equivalence of the accused formulation to the claimed single-layer comparators.
Indefiniteness of “substantially the same,” “rapidly dissolve,” or “substantially intact.”

The patent holder would likely rely on the commercial product’s formulation records, dissolution testing, manufacturing specifications, and claim-scope evidence developed during prosecution.

No conclusion about a specific generic company’s current challenge or settlement should be drawn solely from the existence of this patent. Generic litigation can involve separate Contrave patents, different defendants, settlement dates, licensed launch dates, and confidential commercial terms. Each ANDA applicant must be evaluated through its FDA filing history, paragraph IV notice, district-court docket, and any resulting settlement.

How does this patent compare with other Contrave protections?

The Contrave estate can be divided into four categories:

Protection category	Subject matter	Relevance
Combination claims	Naltrexone and bupropion used together	Can cover the therapeutic combination independent of the exact bilayer design
Formulation claims	Layered tablet with separated sustained-release layers	Core subject of US 8,088,786
Method-of-use claims	Weight-management treatment using the combination	Can create use-code and labeling issues
Manufacturing claims	Compression, coating, granulation, or layer-production processes	May create process and supply-chain barriers

US 8,088,786 is a formulation patent. It does not, based on the supplied claims, claim the treatment of obesity, a particular titration schedule, or a manufacturing process. A complete Contrave freedom-to-operate review must therefore examine the full patent family and all Orange Book-listed patents, not this patent in isolation.

What geographic coverage does US 8,088,786 provide?

The patent provides protection only in the United States. International counterparts may exist in jurisdictions where corresponding national applications were filed and granted, but US 8,088,786 itself has no direct enforcement effect in Europe, Canada, Japan, China, or other countries.

Geographic risk depends on:

national-stage filings;
granted counterpart claims;
local patent-term rules;
supplementary protection or regulatory extensions;
claim amendments during foreign prosecution; and
local litigation and generic-entry rules.

A generic launch strategy must be analyzed separately for the United States, European Union, Canada, Australia, and other markets.

Key Takeaways

US 8,088,786 is directed to a bilayer sustained-release naltrexone/bupropion tablet.
The core invention is a rapidly dissolving sugar layer that separates the two active layers while preserving their individual dissolution profiles.
Contrave’s 8 mg naltrexone and 90 mg bupropion tablet falls within the narrower dosage ranges of claims 3 and 5.
Lactose-containing products face the most direct issue under claim 2.
Claim 6 adds a less-than-one-minute in-vivo separation limitation.
The patent’s expected base term is in the 2028 period, subject to the official USPTO term calculation and any adjustment or extension.
The patent is a formulation patent, not a broad method-of-use patent.
Generic risk depends on the complete Contrave patent estate, Orange Book listings, paragraph IV certifications, litigation, and settlements.
A non-layered tablet or capsule may reduce literal infringement risk but does not eliminate equivalence or other-patent exposure.
Biosimilar analysis is inapplicable because Contrave is a small-molecule drug.

FAQs About US Patent 8,088,786

Does US 8,088,786 cover all naltrexone and bupropion combinations?

No. It requires a specific layered formulation with sustained-release naltrexone, sustained-release bupropion, an intermediate sugar layer, and defined dissolution behavior.

Does the patent require lactose?

No. Lactose is required only by dependent claim 2. Claim 1 covers a broader intermediate layer containing a monosaccharide or disaccharide sugar.

Is an 8 mg/90 mg tablet automatically infringing?

No. The dosage amounts fall within relevant claim ranges, but infringement requires satisfaction of all claim limitations, including the layered structure and dissolution requirements.

Can a generic avoid the patent by using a capsule?

Possibly, if the capsule does not contain the claimed first and second pharmaceutical layers separated by the claimed sugar intermediate layer. Other Contrave patents and equivalence theories would still require review.

Does FDA approval of a generic automatically invalidate the patent?

No. FDA approval and patent validity are separate legal issues. An ANDA applicant may obtain approval after patent expiration, settlement, litigation resolution, or a regulatory determination that the patent does not block approval.

References

United States Patent and Trademark Office. (2012). US Patent No. 8,088,786, Layered pharmaceutical formulation.
U.S. Food and Drug Administration. (2014). Contrave (naltrexone hydrochloride and bupropion hydrochloride) extended-release tablets: Prescribing information.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations.
Drug Price Competition and Patent Term Restoration Act, 21 U.S.C. § 355.

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	CONTRAVE	bupropion hydrochloride; naltrexone hydrochloride	TABLET, EXTENDED RELEASE;ORAL	200063-001	Sep 10, 2014		RX	Yes	Yes	8,088,786	⤷ Start Trial	Y				⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	063959	⤷ Start Trial
Austria	E460925	⤷ Start Trial
Australia	2007319471	⤷ Start Trial
Canada	2668884	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 8,088,786

Which drugs does patent 8,088,786 protect, and when does it expire?

Summary for Patent: 8,088,786