United States Patent 11,033,543: Claim Scope, Exclusivity, Litigation Risk, and Contrave Patent Landscape

U.S. Patent No. 11,033,543 protects a disease-specific method of using naltrexone and bupropion for weight loss in overweight or obese patients who also have major depressive disorder. The patent is narrower than a basic composition patent because it requires a particular patient population and a comparative weight-loss outcome. Its strongest claims are claims 10-19, which recite the 32 mg/360 mg maintenance regimen, dose escalation, sustained release, and, in claim 19, a single therapeutic result in patients with major depressive disorder compared with patients without that disorder.

The patent does not broadly claim all uses of naltrexone and bupropion, all weight-loss treatments, or all treatment of depression. Its commercial relevance depends on whether a competing product or regimen is directed to the patented patient population, uses the claimed dosing architecture, and falls within the claimed sustained-release or comparative efficacy limitations.

What does U.S. Patent 11,033,543 protect?

The patent claims methods of providing weight-loss therapy to overweight or obese patients suffering from major depressive disorder using naltrexone and bupropion.

Claim group	Principal limitation	Commercial significance
Claims 1-4	Naltrexone plus bupropion for an overweight or obese patient with major depressive disorder	Core patient-population and combination-treatment claims
Claims 5-7	Once-daily, multiple-daily, or sequential administration	Covers different administration schedules
Claims 8-9	Single oral dosage form, optionally with excipients	Covers combination tablets or capsules
Claim 10	Naltrexone at about 16 or 32 mg/day and bupropion at about 360 mg/day	Captures principal maintenance dosing
Claim 11	Initial titration followed by 16/360 or 32/360 mg maintenance	Covers treatment initiation and maintenance
Claim 12	Four-week dose-escalation schedules	Covers specific titration protocols
Claims 13-18	Sustained-release formulation of one or both active ingredients	Adds formulation and release-profile limitations
Claim 19	32 mg/day naltrexone, 360 mg/day bupropion, sustained release for both, and comparable weight loss in patients with and without major depressive disorder	Narrowest but commercially targeted claim

The claims cover naltrexone and bupropion individually or as pharmaceutically acceptable salts. They do not require a particular salt in the claim language. A product using naltrexone hydrochloride and bupropion hydrochloride would fall within the chemical form contemplated by the claims if the other limitations were met.

How does claim 1 define the patent’s broadest method?

Claim 1 has four material limitations:

The patient must be overweight or obese.
The patient must suffer from major depressive disorder.
The treatment must administer naltrexone at about 4 mg to about 50 mg per day and bupropion at about 30 mg to about 500 mg per day.
The method must provide about the same amount of weight loss in patients with major depressive disorder as in comparable overweight or obese patients without major depressive disorder.

The patient-population limitation is central. A weight-loss regimen administered to a patient who is obese but does not have major depressive disorder would not meet claim 1. Conversely, treatment of major depressive disorder in a normal-weight patient would not meet the overweight-or-obese limitation.

The amounts are broad. The naltrexone range spans 4-50 mg per day, while the bupropion range spans 30-500 mg per day. Those ranges encompass the commercially relevant 32 mg/360 mg regimen and many lower-dose regimens.

The phrase “about the same amount of weight loss” is a functional and comparative limitation. It is not defined in the supplied claims by a numerical tolerance, treatment duration, statistical test, or comparator population. That creates both scope and enforcement issues. The patentee would likely rely on the specification, prosecution history, clinical data, and ordinary meaning of “about” to establish the required comparison.

What are the strongest and weakest limitations in the claims?

Strongest limitations

The most commercially meaningful limitations are:

major depressive disorder as a required comorbidity;
the 32 mg/day naltrexone and 360 mg/day bupropion regimen;
sustained release for each active ingredient;
four-week dose escalation;
treatment of weight loss rather than depression alone;
the comparative result showing similar weight loss regardless of depressive-disorder status.

These limitations align closely with the pharmacologic profile and labeled dosing architecture of naltrexone/bupropion extended-release therapy.

Weaker or more vulnerable limitations

The comparative efficacy language may create an invalidity or enforcement vulnerability. “About the same amount” may be challenged as indefinite under 35 U.S.C. §112(b) if the specification and prosecution history do not provide an objective boundary. The limitation may also raise enablement and written-description questions if the patent does not support the full range of:

naltrexone from 4 to 50 mg/day;
bupropion from 30 to 500 mg/day;
all overweight and obese patients with major depressive disorder;
all acceptable salts;
all dosing schedules;
all sustained-release formulations.

Claim 1 also requires administering both active ingredients but does not require a single tablet. A competitor could therefore face risk from separate prescriptions or separate dosage forms if the patient population, doses, and outcome limitations are met.

What formulations are protected by U.S. Patent 11,033,543?

Claims 13-18 protect sustained-release implementations.

Claim 13 requires at least one active ingredient to be in a sustained-release formulation. Claim 15 requires each active ingredient to be sustained release. Claims 14 and 16 add the single oral dosage-form limitation.

This produces a practical distinction:

Formulation configuration	Potentially covered
Immediate-release naltrexone plus immediate-release bupropion	Generally outside claims 13-18, but potentially within claim 1
Sustained-release naltrexone plus immediate-release bupropion	Potentially within claims 13 and 17
Immediate-release naltrexone plus sustained-release bupropion	Potentially within claims 13 and 17
Sustained-release naltrexone plus sustained-release bupropion	Potentially within claims 15 and 18
Both sustained release in one tablet	Potentially within claims 14, 16, and 19
Both sustained release in separate dosage forms	Potentially within claims 15, 18, and 19, subject to the other limitations

The claims do not expressly recite a particular dissolution profile, polymer, matrix system, tablet layer, particle size, coating, or release duration. Those technical features may be relevant to infringement and validity only if they are required by another patent or imported through claim construction, not because they appear in the supplied claims.

How does claim 19 compare with claim 1?

Claim 19 is materially narrower than claim 1 but more closely aligned with a commercial extended-release product.

Feature	Claim 1	Claim 19
Patient	Overweight or obese with major depressive disorder	Same
Naltrexone dose	About 4-50 mg/day	About 32 mg/day
Bupropion dose	About 30-500 mg/day	About 360 mg/day
Release profile	Not required	Both active ingredients sustained release
Dosage form	Not required	Not expressly required to be single dosage form
Comparative result	Required	Required
Breadth	Broadest independent claim	Narrower, regimen-specific independent claim

Claim 19 may be easier to map onto a commercial product because it recites the standard maintenance doses and sustained-release characteristics. It may also be easier to defend against prior-art references directed to lower doses, immediate-release products, or treatment of depression without the claimed weight-loss comparison.

When does U.S. Patent 11,033,543 lose exclusivity?

U.S. Patent 11,033,543 issued on June 15, 2021. Its term depends on the earliest effective nonprovisional priority date, any terminal disclaimer, and any patent-term adjustment. The issue date alone does not establish the expiration date.

A patent-family and Patent Center review is required to determine:

the earliest effective priority date;
whether the patent is a continuation or divisional;
whether a terminal disclaimer applies;
the amount of patent-term adjustment;
whether patent-term extension was granted;
whether maintenance fees remain paid.

For a standard utility patent, the baseline term is generally 20 years from the earliest effective nonprovisional filing date under 35 U.S.C. §154. Patent-term adjustment can extend that period, while a terminal disclaimer can shorten it.[2]

The patent’s expiration date should therefore be taken from the USPTO Patent Center record or an authoritative patent-term calculation, not inferred solely from the issue date.

What is the FDA and Orange Book status of the covered therapy?

The commercial product associated with this patent landscape is Contrave, an extended-release combination of naltrexone hydrochloride and bupropion hydrochloride. FDA approved Contrave under NDA 200063 for chronic weight management in adults with obesity or overweight status with at least one weight-related comorbidity, used with a reduced-calorie diet and increased physical activity.[3]

The FDA-approved indication is weight management. It is not an indication for treating major depressive disorder. The patent therefore claims a narrower use population than the principal FDA indication.

The Orange Book analysis should distinguish among:

patents listed for the approved drug product;
patents covering the active ingredients or dosage form;
method-of-use patents directed to the approved indication;
method-of-use patents directed to an unapproved subpopulation or clinical result;
regulatory exclusivity under the Federal Food, Drug, and Cosmetic Act.

A method claim directed to overweight or obese patients with major depressive disorder may not automatically block an ANDA directed to the full approved weight-management indication. Its practical effect depends on the listed use, the ANDA’s proposed labeling, any section viii statement, and whether the patent is listed in the Orange Book for the relevant NDA.[4]

What Paragraph IV and generic-entry risks exist?

A generic applicant could approach the patent in several ways.

Paragraph IV strategy

A Paragraph IV certification could challenge the patent on grounds including:

anticipation;
obviousness;
lack of written description;
lack of enablement;
indefiniteness of “about the same amount of weight loss”;
noninfringement based on the proposed label;
failure to meet the major-depressive-disorder limitation;
failure to meet sustained-release limitations;
failure to meet the specified dose or titration schedule.

The comparative weight-loss limitation may be difficult to litigate at the ANDA stage if infringement depends on clinical outcomes that are not directly visible from the product composition. A patentee could argue that the claimed result is an inherent or expected result of the claimed regimen. The applicant could respond that a product label does not induce the patented method or that the limitation cannot be established without patient-specific evidence.

Section viii strategy

If the Orange Book listing is directed to an unapproved method of use, a generic applicant may attempt a section viii statement carving that use out of the proposed labeling. The success of that strategy depends on the FDA-listed patent use code and whether the remaining label still encourages conduct that would practice the claim.

Noninfringing design-around

Potential design-around positions include:

excluding patients diagnosed with major depressive disorder from the label;
using a regimen outside the claimed dose ranges;
using a different formulation that is not sustained release;
using separate immediate-release products;
avoiding a label or marketing statement directed to comparable weight loss in patients with and without major depressive disorder.

These strategies carry different regulatory and inducement risks. A product can avoid literal infringement while still presenting risk if its labeling, promotional materials, or prescribing instructions encourage the claimed use.

Which companies control or challenge the Contrave patent estate?

Contrave was developed by Orexigen Therapeutics and is commercially associated with Currax Pharmaceuticals. Orexigen transferred or licensed rights relating to Contrave during the product’s commercial development and later corporate restructuring. The specific ownership of U.S. Patent 11,033,543 must be determined from the current USPTO assignment record rather than inferred from the product’s marketing company.

The relevant competitive groups are:

Group	Strategic position
Contrave rights holder	Defends formulation, dosing, and method-of-use rights
ANDA applicants	Seek approval for generic naltrexone/bupropion extended-release products
Obesity-drug developers	Compete through GLP-1, dual agonist, and other weight-loss therapies
Bupropion and naltrexone manufacturers	May supply active ingredients or alternative dosage forms
Digital and specialty obesity providers	May affect prescribing volume and label-use evidence

No litigation disposition, settlement term, or named Paragraph IV challenger is established by the claim text alone. Those facts must be tied to docket records, FDA litigation correspondence, Orange Book certifications, or SEC disclosures.

How strong is the patent estate?

The estate’s strength is mixed.

Factor	Assessment
Product alignment	Strong for a 32/360 mg extended-release regimen
Patient-population specificity	Limits claim breadth but improves targeting
Formulation protection	Moderate; the claims lack detailed structural formulation limitations
Comparative-result limitation	Commercially useful but potentially vulnerable to indefiniteness and proof disputes
Prior-art exposure	Significant because naltrexone, bupropion, depression treatment, and obesity treatment were separately well known
Generic design-around risk	Moderate to high for labels excluding major depressive disorder or using non-sustained-release regimens
Litigation leverage	Highest if the patent is Orange Book listed and the generic label overlaps the claimed method
Biosimilar relevance	None; this is a small-molecule combination product, not a biologic

The patent is more important as a targeted method-of-use layer than as the sole barrier to generic entry. Formulation patents, composition patents, regulatory exclusivity, and other method patents in the Contrave estate may provide separate barriers.

How does this patent compare with formulation and composition patents?

U.S. Patent 11,033,543 is a method patent. It protects what is done, to whom, and at what dosing regimen.

A formulation patent generally protects the product itself, such as:

a sustained-release matrix;
a specific ratio of naltrexone to bupropion;
a particular dissolution profile;
a tablet architecture;
excipient combinations;
manufacturing parameters.

A composition or formulation patent can create greater generic exposure because infringement may be established by analyzing the product rather than proving the physician’s treatment decisions and the patient’s clinical outcome. The method patent has narrower patient and use limitations but may remain relevant after broader product claims expire if the generic label continues to promote the patented use.

What manufacturing and geographic barriers apply?

The supplied claims do not claim a manufacturing process. A manufacturer could therefore practice the claimed method only if its product is used in a manner meeting the treatment limitations. Separate patents may protect tablet manufacture, sustained-release technology, coating systems, granulation, or dissolution specifications.

U.S. Patent 11,033,543 has territorial effect only in the United States. It does not directly block manufacture, sale, or use outside the United States. Foreign family members must be analyzed separately for:

grant status;
claim amendments;
national-phase scope;
opposition or post-grant proceedings;
local patent-term rules;
regulatory linkage;
country-specific generic-entry rules.

Key Takeaways

U.S. Patent 11,033,543 is a targeted method-of-use patent for weight-loss treatment in overweight or obese patients with major depressive disorder.
Claim 1 requires naltrexone, bupropion, the specified dose ranges, and a comparative weight-loss result.
Claims 10-12 target the commercially important 32 mg/360 mg regimen and titration schedule.
Claims 13-18 add sustained-release limitations; claim 19 requires sustained release for both active ingredients.
The patent does not broadly claim Contrave, naltrexone, bupropion, or all obesity treatment.
“About the same amount of weight loss” is central to infringement but may generate indefiniteness, enablement, and proof disputes.
Generic risk depends heavily on the proposed label, Orange Book listing, use code, and whether the generic promotes treatment of patients with major depressive disorder.
This is a small-molecule patent estate. Biosimilar analysis is not applicable.
The patent’s exact expiration date requires the USPTO priority, terminal-disclaimer, patent-term-adjustment, and maintenance-fee records.

FAQs

Does U.S. Patent 11,033,543 cover Contrave itself?

No. It covers methods of using naltrexone and bupropion in a defined patient population and under specified clinical conditions. Product composition and formulation protection must be analyzed separately.

Can a generic avoid this patent by omitting major depressive disorder from its label?

Potentially, but omission alone does not resolve every infringement issue. The analysis depends on the final label, prescribing instructions, promotional activity, FDA patent certification, and whether the remaining label encourages the claimed method.

Does claim 19 require a single combination tablet?

No. Claim 19 requires sustained-release naltrexone and sustained-release bupropion at approximately 32 mg/day and 360 mg/day. It does not expressly require that both ingredients be in one dosage form.

Is the patent relevant to obesity drugs such as semaglutide or tirzepatide?

Generally no. The claims require naltrexone and bupropion. GLP-1 receptor agonists and related incretin therapies do not meet that active-ingredient limitation.

What evidence would be important in litigation over the comparative weight-loss limitation?

Relevant evidence would include the patent specification, prosecution history, clinical-trial data, statistical definitions, product labeling, physician instructions, prescribing data, and comparative studies involving patients with and without major depressive disorder.

References

U.S. Patent No. 11,033,543, Methods for providing weight loss therapy to overweight or obese patients suffering from major depressive disorder (U.S. Patent and Trademark Office, 2021).
United States Code, 35 U.S.C. §§ 154, 156, 271, and 282.
U.S. Food and Drug Administration. (2014). Contrave prescribing information: Naltrexone hydrochloride and bupropion hydrochloride extended-release tablets. FDA.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations, commonly known as the Orange Book. FDA.
U.S. Patent and Trademark Office. (2024). Patent Center and assignment records. USPTO.

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	⤷ Start Trial	⤷ Start Trial				FOR CHRONIC WEIGHT MANAGEMENT FOR TREATING OVERWEIGHT OR OBESITY	⤷ 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
Australia	2011203867	⤷ Start Trial
Australia	2016201325	⤷ Start Trial
Brazil	112012016783	⤷ Start Trial
Canada	2785822	⤷ Start Trial
China	102724878	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 11,033,543

Which drugs does patent 11,033,543 protect, and when does it expire?

Summary for Patent: 11,033,543