Details for Patent: 7,462,626

Summary for Patent: 7,462,626

Title:	Compositions for affecting weight loss
Abstract:	Disclosed are compositions for affecting weight loss comprising a first compound and a second compound, where the first compound is an opioid antagonist and the second compound causes increased agonism of a melanocortin 3 receptor (MC3-R) or a melanocortin 4 receptor (MC4-R) compared to normal physiological conditions. Also disclosed are methods of affecting weight loss, increasing energy expenditure, increasing satiety in an individual, or suppressing the appetite of an individual, comprising identifying an individual in need thereof and treating that individual to antagonize opioid receptor activity and to enhance α-MSH activity.
Inventor(s):	Eckard Weber, Michael Alexander Cowley
Assignee:	Nalpropion Pharmaceuticals LLC
Application Number:	US11/356,839
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 7,462,626
Patent Claim Types: see list of patent claims	Use; Formulation; Dosage form;

United States Drug Patent 7,462,626: Claim Scope, Expiration, Contrave Patent Landscape, and Generic Entry Risk

U.S. Patent No. 7,462,626 covers methods of treating overweight or obesity with a combination of naltrexone and bupropion. Its independent claims require administration of both compounds, with claim 1 requiring naltrexone to enhance bupropion-associated weight loss and claim 25 requiring enhanced weight-loss activity compared with either compound alone. The patent’s original term has expired, so it is no longer the principal U.S. exclusionary barrier for Contrave. Later continuation and formulation patents, FDA regulatory exclusivity, and Orange Book-listed patents remain more relevant to generic entry.

What does U.S. Patent 7,462,626 protect?

U.S. Patent 7,462,626 protects a therapeutic method rather than a new chemical compound. The claimed invention is the use of naltrexone and bupropion together to treat overweight or obesity.

The patent issued on Dec. 9, 2008, from an application claiming priority to a 2001 filing. The patent is associated with the development of the naltrexone/bupropion combination later commercialized as Contrave.

Patent	Subject matter	Issue date	Earliest priority	Original 20-year term
U.S. 7,462,626	Methods of treating overweight or obesity using naltrexone and bupropion	Dec. 9, 2008	2001	Expired in 2022

The patent does not claim:

• Naltrexone as a standalone molecule
• Bupropion as a standalone molecule
• A new chemical entity
• A specific salt of naltrexone or bupropion as a composition independent of the method
• Every possible use of the two drugs outside overweight or obesity treatment

Its commercial importance came from applying two known drugs to a new therapeutic objective and claiming specific treatment parameters around the combination.

What are the independent claims in Patent 7,462,626?

Claim 1: BMI-diagnosed patient and pharmacologic enhancement

Claim 1 requires all of the following:

1. Diagnosing an individual as overweight or obese.
2. Determining that the individual has a BMI of at least 25 kg/m².
3. Administering bupropion or a pharmaceutically acceptable salt in an amount effective to induce weight loss.
4. Administering naltrexone or a pharmaceutically acceptable salt in an amount effective to enhance the weight-loss activity of bupropion.
5. Treating the individual’s overweight or obesity.

Claim 1 is broad in drug-formulation terms. It does not require:

• A single tablet
• Sustained release
• A particular fixed-dose ratio
• A particular daily dosing schedule
• A particular duration of therapy
• A specific percentage of weight loss
• A specific mechanism of action

The BMI diagnosis limitation narrows the claim to patients meeting the stated diagnostic threshold. A regimen for a patient who is not diagnosed with overweight or obesity would not satisfy the claim as written.

Claim 25: Comparative enhanced activity

Claim 25 covers treatment with both compounds where the combination’s weight-loss activity is enhanced compared with administration of the same amount of either compound alone.

This claim contains a more explicit comparative-performance limitation than claim 1. A claimant would need to establish that the combination produces enhanced weight-loss activity relative to one or both single-agent treatments under the relevant comparison.

The two independent claims overlap but are not identical:

Issue	Claim 1	Claim 25
Patient diagnosis	BMI at least 25 kg/m² expressly required	Diagnosed with overweight or obesity; BMI threshold appears in dependent claims
Compound order	Naltrexone is first compound; bupropion is second	Bupropion is first compound; naltrexone is second
Functional limitation	Naltrexone enhances bupropion’s weight-loss activity	Combination activity is enhanced versus either compound alone
Formulation	Not required	Not required
Comparative testing	Not expressly stated	Expressly required
Treatment objective	Treat overweight or obesity	Treat overweight or obesity

The claim-number labels for “first” and “second” compound do not create a meaningful commercial distinction. The claims cover the same active ingredients in either recited order.

How broad are the dependent claims?

The dependent claims expand the patent’s coverage across dosing, formulation, patient selection, treatment duration, and treatment outcomes.

Drug administration and dosage

Claims 2, 3, 26 and 27 cover coadministration as well as sequential administration. The drugs can be given together, or one can be given before or after the other.

Claims 9 to 11 and 34 to 36 specify broad daily ranges:

Active ingredient	Claimed daily range
Naltrexone	About 5 mg to about 50 mg
Bupropion	About 30 mg to about 500 mg

These ranges are broad enough to encompass the active-ingredient quantities used in commercial naltrexone/bupropion extended-release therapy, subject to the specific formulation and titration schedule.

Claims 15, 16 and 41 cover administration in a single oral dosage form. Claims 6, 12, 13, 30, 37 and 38 cover sustained-release formulations for either or both active ingredients.

Patient characteristics

Claim 4 and claim 28 exclude patients suffering from depression. This limitation is commercially relevant because bupropion is also marketed for depression and smoking cessation. The exclusion helps distinguish obesity treatment from certain conventional bupropion uses.

Claims 14, 39 and 40 address BMI thresholds:

• At least 25 kg/m²
• At least 30 kg/m²

The 30 kg/m² threshold corresponds generally to obesity, while the 25 kg/m² threshold captures overweight patients.

Claims 20 and 45 cover patients with complications or comorbidities, including:

• Hypertension
• Type 2 diabetes
• Arteriosclerosis
• Dyslipidemia
• Cancer
• Sleep apnea
• Osteoarthritis

Treatment response and duration

Claims 17, 18, 42 and 43 cover dose adjustment. The claims include adjustment designed to achieve treatment objectives, including a stated weight-loss rate of 10% of initial body weight every six months.

Claims 21 and 46 require administration at least once daily. Claims 22, 23, 47 and 48 specify treatment periods of at least 16 or 24 weeks.

Claims 24 and 49 cover continued treatment until the patient achieves at least 5% weight loss or reaches a BMI below 25 kg/m².

Combination with zonisamide

Claims 5 and 29 add zonisamide to the treatment regimen. These claims extend beyond a two-drug naltrexone/bupropion regimen and create a narrower tripartite combination.

A product containing only naltrexone and bupropion would not practice the zonisamide claims. Conversely, adding zonisamide could create exposure under those claims if the remaining limitations are met.

What is the patent strength of U.S. 7,462,626?

The patent had meaningful commercial scope when enforceable, but its present blocking strength is limited because the original patent term has expired.

Strengths during the enforceable term

The patent had several features favorable to enforcement:

• It covered the therapeutic combination rather than only a narrow tablet design.
• It reached coadministration and sequential administration.
• It covered separate dosage forms and a single oral dosage form.
• It included broad active-ingredient ranges.
• It reached both overweight and obese patients through BMI-dependent claims.
• It included sustained-release formulations.
• It covered treatment with or without diet and increased activity.
• It did not require a particular fixed-dose ratio in the independent claims.

Limitations and potential validity issues

The claims also contained limitations that could have created litigation vulnerabilities:

1. Functional enhancement language
   The requirement that naltrexone enhance bupropion’s weight-loss activity, or that the combination show enhanced activity over either agent alone, can generate disputes over proof and claim construction.

2. Method-of-treatment characterization
   The claims require treatment of an appropriately diagnosed patient. Product-only infringement is not established merely by making or selling the tablets.

3. Known-drug combination prior art
   Both naltrexone and bupropion were known drugs. The principal patentability issue would have focused on whether the claimed combination, obesity indication, dosing, and observed activity were nonobvious.

4. Written-description and enablement questions
   The breadth of the claimed dosage ranges, treatment duration, formulation formats, and functional results could have been challenged depending on the supporting disclosure and prosecution history.

5. Divided-infringement issues
   Claims requiring diagnosis, administration, dose adjustment, and treatment duration can create proof issues when multiple actors perform different steps.

6. Expired patent
   These issues now have limited practical value for ordinary U.S. commercial entry because the patent term has ended.

When did U.S. Patent 7,462,626 lose exclusivity?

The patent’s original 20-year term ran from its earliest nonprovisional filing and expired in 2022. The patent is therefore not a current U.S. patent barrier to generic naltrexone/bupropion products.

The patent’s expiration does not eliminate other patent rights in the same product area. Continuation patents may have different claim sets, priority chains, patent-term-adjustment periods, or later priority dates. A freedom-to-operate analysis must therefore distinguish Patent 7,462,626 from later patents in the family and related formulation patents.

Patent expiration also does not eliminate:

• FDA-approved-use limitations
• Orange Book patent certifications
• Regulatory exclusivity
• Product-label and prescribing-information issues
• Separate patent rights covering formulations or manufacturing processes

What patents followed U.S. 7,462,626 in the Contrave patent estate?

The naltrexone/bupropion estate developed through continuation and related formulation filings. The principal U.S. patent families associated with Contrave and the combination include the following categories:

Patent family or patent	General subject matter	Commercial relevance
U.S. 7,462,626	Broad method of treating overweight or obesity with naltrexone and bupropion	Foundational combination-use patent; expired
U.S. 8,017,669	Later method-of-use claims for naltrexone/bupropion weight-loss treatment	Potentially relevant during its enforceable term
U.S. 8,628,657	Pharmaceutical compositions containing naltrexone and bupropion	Formulation and composition protection
U.S. 9,616,079	Later method-of-use claims involving the combination	Use-related protection
Later formulation patents and continuations	Extended-release dosage forms, composition parameters, and commercial product configurations	Potential later-entry barriers

The exact relevance of each patent depends on:

• Whether it was listed for NDA 200063
• Whether its claims cover the proposed generic product
• Its expiration date
• Any terminal disclaimer
• Any patent-term adjustment
• The generic applicant’s Paragraph IV position
• Litigation or settlement terms

The Orange Book should be reviewed by NDA and supplement because listings can change over time. The existence of a patent in the family does not establish that it is currently listed against Contrave or that it covers every generic formulation.

What is the FDA and Orange Book status of Contrave?

Contrave is an extended-release oral combination of naltrexone hydrochloride and bupropion hydrochloride. The FDA approved Contrave under NDA 200063 on Sept. 10, 2014, for chronic weight management in adults with obesity or overweight accompanied by at least one weight-related comorbidity.[2]

The labeled indication generally requires use with a reduced-calorie diet and increased physical activity. The FDA label identifies a titration schedule and warns about risks associated with bupropion and naltrexone, including seizures, blood pressure increases, opioid-related contraindications, and psychiatric effects.[2]

Regulatory item	Status
Product	Contrave extended-release tablets
Active ingredients	Naltrexone hydrochloride and bupropion hydrochloride
FDA application	NDA 200063
Sponsor history	Orexigen Therapeutics; later commercial rights associated with Currax
Dosage form	Oral extended-release tablet
Regulatory pathway for generics	ANDA, with applicable patent certifications
Biosimilar pathway	Not applicable

Contrave is a small-molecule product. Biosimilar risk does not apply. Competitive risk comes from abbreviated new drug applications, authorized-generic strategies, compounding activity, and alternative anti-obesity medicines.

Which companies have challenged Contrave patents?

Public generic-drug challenges to Contrave have involved ANDA applicants and related patent litigation. The relevant parties and proceedings must be matched to specific docket numbers, patents and filing dates because a Paragraph IV notice is not equivalent to a court finding of invalidity or noninfringement.

The principal commercial threat is an ANDA applicant seeking approval for a product containing the same active ingredients and dosage form. A generic applicant may:

• Certify that no relevant patent is listed
• Certify that a listed patent has expired
• File a Paragraph IV certification alleging invalidity, unenforceability or noninfringement
• Submit a section viii statement seeking approval for nonpatented uses

For a product directed to the full Contrave indication, a section viii strategy may be difficult if the generic label necessarily includes the patented obesity use. A successful carve-out would depend on the scope of the approved labeling and the specific Orange Book claims.

What Paragraph IV risks arise from the expired patent?

U.S. Patent 7,462,626 itself should not support a current Paragraph IV litigation strategy because its patent term has expired. A generic applicant can rely on expiration rather than contesting the patent’s validity or infringement.

The remaining Paragraph IV risk would arise from later unexpired patents, particularly patents directed to:

• Extended-release compositions
• Single-tablet dosage forms
• Specific naltrexone/bupropion ratios
• Release profiles
• Dosing and titration methods
• The approved obesity indication
• Commercial manufacturing characteristics

A generic product could avoid some formulation claims by using different excipients, release technology or tablet architecture. It may be harder to avoid method-of-use claims if the approved label directs treatment of obesity with the same two active ingredients.

What manufacturing and formulation barriers remain?

Patent 7,462,626 does not require a specific manufacturing process. It therefore creates little current manufacturing protection after expiration.

Later formulation patents may present a more important barrier. Contrave uses an extended-release tablet, and a generic manufacturer must demonstrate pharmaceutical equivalence and bioequivalence while avoiding enforceable composition or release-profile claims.

Potential design-around routes include:

• Separate immediate-release and extended-release products
• A different controlled-release matrix
• Different excipient systems
• A different tablet architecture
• Alternative salt or particle characteristics, subject to FDA requirements
• A label that omits nonprotected uses where legally and regulatorily feasible

A design-around must be assessed claim by claim. Changing excipients does not avoid a claim that is defined primarily by active ingredients and dosage amounts. Conversely, a changed release mechanism may avoid a formulation claim even if the product still practices an expired method-of-use claim.

How does the patent estate compare with competing obesity drugs?

Contrave’s original estate was built around a repurposed-drug combination. That differs from newer obesity medicines based on proprietary active ingredients and biologic or peptide platforms.

Product category	Main IP type	Generic or biosimilar exposure
Contrave	Small-molecule combination, method-of-use and extended-release formulation patents	ANDA and Paragraph IV risk
GLP-1 peptide products	Compound, formulation, device, method-of-use and manufacturing patents	Later and technically more complex entry
Older anti-obesity drugs	Compound, formulation or use patents, often expired or near expiry	Greater generic exposure
Combination products	Synergy, dosing, release and treatment-method claims	Infringement often depends on label and regimen

Contrave has no biosimilar pathway because it is not a biologic. Its principal long-term risk is generic substitution rather than biosimilar interchangeability.

What commercial exposure does Contrave face from generic entry?

Generic entry would affect pricing, payer coverage, pharmacy substitution and market share. The exposure is highest because:

• The active ingredients are inexpensive and widely available.
• Bupropion and naltrexone each have long histories of generic use.
• The product is administered orally.
• The combination does not depend on a biologic manufacturing platform.
• Generic manufacturers can use the ANDA pathway if they establish equivalence.
• The original foundational method patent has expired.

The remaining commercial protection depends on the duration and enforceability of later listed patents, the outcome of any Paragraph IV cases, and any settlement terms governing launch dates.

Are there licensing deals for the naltrexone/bupropion combination?

The combination was developed through rights associated with Orexigen Therapeutics and academic-origin technology. Orexigen entered into a U.S. commercialization arrangement with Takeda for Contrave. Takeda later returned or terminated its commercial relationship, after which Orexigen’s assets and Contrave-related rights moved through subsequent corporate transactions, including ownership associated with Currax Pharmaceuticals.

The relevant diligence question is whether the licensed patent rights include:

• The foundational combination-use patents
• Continuation patents
• Formulation patents
• Foreign counterparts
• Know-how and clinical data
• Rights to enforce patents against ANDA applicants

A commercial license does not extend patent term. It can affect enforcement authority, royalty economics and settlement rights.

Key Takeaways

• U.S. Patent 7,462,626 claims treating overweight or obesity with naltrexone and bupropion.
• Claims 1 and 25 are the principal independent claims.
• The patent covers coadministration, sequential administration, broad dosage ranges, sustained release, single oral dosage forms and defined patient populations through dependent claims.
• Claim 1 focuses on naltrexone enhancing bupropion’s weight-loss activity.
• Claim 25 requires enhanced activity compared with either compound alone.
• The original patent term expired in 2022 and is no longer the principal U.S. barrier to generic entry.
• Current risk depends on later continuation, formulation and method-of-use patents listed for Contrave NDA 200063.
• Contrave is an FDA-approved small-molecule combination, so biosimilar risk does not apply.
• Generic applicants face ANDA requirements and may use Paragraph IV certifications against unexpired Orange Book patents.
• Formulation and label-based method-of-use claims are more important to current entry risk than Patent 7,462,626 itself.

FAQs

Does Patent 7,462,626 cover generic bupropion?

No. It does not claim bupropion alone. It claims methods that use bupropion together with naltrexone to treat overweight or obesity.

Does taking naltrexone and bupropion separately practice the patent?

It can fall within the method claims if the drugs are administered in the claimed manner and all other limitations are satisfied. The claims expressly cover administration together or in sequence.

Does Patent 7,462,626 require Contrave’s exact tablet strength?

No. The independent claims do not require Contrave’s exact commercial strength or fixed-dose ratio. Dependent claims recite broad daily ranges for naltrexone and bupropion.

Can a generic omit the obesity indication from its label?

Potentially, but the answer depends on the approved reference labeling, the scope of any unexpired method-of-use patents, FDA requirements and whether the proposed label still encourages the patented use. A label carve-out does not automatically eliminate infringement risk.

Is the naltrexone/bupropion combination protected outside the United States?

Foreign counterparts may have different claim scopes, expiration dates, prosecution histories and legal status. U.S. expiration does not determine the status of corresponding patents in Europe, Canada, Japan or other jurisdictions.

References

1. U.S. Patent and Trademark Office. (2008). U.S. Patent No. 7,462,626, methods of treating overweight or obesity using bupropion and naltrexone.
2. U.S. Food and Drug Administration. (2023). Contrave prescribing information.
3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
4. U.S. Patent and Trademark Office. (2024). Patent Center: U.S. Patent No. 7,462,626 and related continuation records.
5. Orexigen Therapeutics, Inc. (2016). Annual report on Form 10-K. U.S. Securities and Exchange Commission.

Drugs Protected by US Patent 7,462,626

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate

International Family Members for US Patent 7,462,626

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	2316456		CA 2017 00062	Denmark
European Patent Office	2316456		300918	Netherlands
European Patent Office	2316456		122017000109	Germany
European Patent Office	2316456		LUC00054	Luxembourg
European Patent Office	2316456		2017C/064	Belgium
European Patent Office	2316456		CR 2017 00062	Denmark
European Patent Office	2316456		1790064-8	Sweden