US Patent 9,107,837: Scope, Claims, Expiration, Orange Book Status, and Contrave Patent Landscape

US Patent 9,107,837 protects specific methods of treating overweight and obesity with sustained-release naltrexone and sustained-release bupropion. Its principal limitation is a defined naltrexone dissolution profile designed to reduce adverse effects, particularly nausea, while maintaining systemic exposure. The patent covers both single-tablet and separate-dosage-form administration, including the commercial 32 mg naltrexone/360 mg bupropion daily regimen associated with Contrave.

The patent is narrower than a general combination patent. A potentially infringing product must satisfy the dosage, sustained-release, dissolution, administration, and therapeutic-use limitations recited in the asserted claim.

What drug does US Patent 9,107,837 protect?

US 9,107,837 protects methods using the combination of:

Active ingredient	Claimed daily amount
Naltrexone	About 4 mg to about 32 mg in claim 1
Bupropion	About 90 mg to about 360 mg in claim 1
Commercial full dose	32 mg naltrexone and 360 mg bupropion daily

The patent concerns oral treatment of overweight or obesity using sustained-release formulations of both active ingredients. The claimed method is directed to reducing adverse effects associated with immediate-release naltrexone, especially nausea, headache, and dizziness.

The commercial product most directly associated with this patent is Contrave, an extended-release combination of naltrexone hydrochloride and bupropion hydrochloride marketed by Currax Pharmaceuticals. Contrave was approved by the U.S. Food and Drug Administration in September 2014 under NDA 200063. [2]

What are the key limitations of US 9,107,837 claims?

Claim 1 contains the core combination of clinical, dosage, formulation, dissolution, and adverse-effect limitations.

Claim 1: broadest independent claim

Claim 1 requires:

A subject in need of treatment for overweight or obesity.
Daily oral administration.
Approximately 4 mg to 32 mg of naltrexone.
Approximately 90 mg to 360 mg of bupropion.
Sustained-release bupropion.
Sustained-release naltrexone.
A specified in vitro naltrexone dissolution profile:
- 67% to 80% released after one hour.
- 85% to 96% released after two hours.
At least one reduced adverse effect compared with the same amount of immediate-release naltrexone administered with sustained-release bupropion.

The dissolution test is specifically defined as USP Apparatus 2, paddle method, at 100 rpm, using water at 37°C.

This is a formulation-dependent method claim. The patent does not cover every sustained-release naltrexone/bupropion regimen. The naltrexone dosage form must meet the specified dissolution windows, and the claimed treatment must have the stated reduced-adverse-effect relationship.

Claims 2 and 14: commercial dosing

Claim 2 identifies specific dose combinations, including:

4 mg naltrexone and 90 mg bupropion;
8 mg naltrexone and 180 mg bupropion;
12 mg naltrexone and 270 mg bupropion;
16 mg naltrexone and 360 mg bupropion;
24 mg naltrexone;
36 mg naltrexone.

The inclusion of 36 mg naltrexone in claim 2 is notable because claim 1 recites approximately 4 mg to 32 mg. As a dependent claim, claim 2 presents a claim-construction and validity issue if the 36 mg alternative is treated as outside the scope of claim 1. The inconsistency does not necessarily affect the 32 mg commercial regimen, but it creates a potential prosecution-history and indefiniteness issue for the 36 mg alternative.

Claim 14 is directed to the full daily commercial regimen:

32 mg naltrexone daily;
360 mg bupropion daily;
16 mg naltrexone twice daily;
180 mg bupropion twice daily;
sustained-release formulations;
the one-hour and two-hour dissolution limits;
at least 99% naltrexone release after eight hours.

Claims 15 through 17 narrow claim 14 to single-unit dosing and adverse effects including nausea.

What formulations are protected by US 9,107,837?

The patent protects sustained-release naltrexone formulations meeting a defined release profile. The claims also cover sustained-release bupropion, but they do not impose an equivalent detailed bupropion dissolution profile in the claims supplied.

Naltrexone dissolution requirements

Test point	Claimed release
One hour	67% to 80%
Two hours	85% to 96%
Eight hours	At least 99% in claims 7, 10, and 14
Four hours	Less than 98% in claims 9 and 10

Claims 7, 9, and 10 add further release-rate limitations. Claim 10 combines the less-than-98% four-hour limitation with at least 99% release at eight hours.

These limitations create a defined release curve rather than a single end-point specification. A competing product that releases too slowly at one hour, too quickly at two hours, or fails to reach 99% by eight hours may fall outside the literal dissolution limitations.

Single-tablet and separate-tablet coverage

Claims 3 and 5 cover administration of sustained-release naltrexone and sustained-release bupropion in a single oral unit dosage form. This language is consistent with a fixed-dose combination tablet.

Claim 13 covers separate oral dosage forms. A generic manufacturer therefore cannot avoid the patent solely by placing naltrexone and bupropion in separate tablets if the other claim limitations are met.

How do the plasma pharmacokinetic claims affect patent scope?

Claims 4 and 6 add pharmacokinetic limitations comparing sustained-release naltrexone with an equal amount of immediate-release naltrexone hydrochloride.

Naltrexone pharmacokinetic limitations

Claim 4 requires:

Naltrexone Cmax below 80% of the immediate-release comparator.
Naltrexone AUClast between 80% and 125% of the comparator.

Claim 6 applies similar requirements to the active metabolite 6-beta naltrexol:

6-beta naltrexol Cmax below 80% of the immediate-release comparator.
6-beta naltrexol AUClast between 80% and 125% of the comparator.

The commercial and litigation significance is substantial. A formulation could meet the dissolution profile but fail the dependent claims if it does not produce the claimed plasma profile. Conversely, a product meeting the pharmacokinetic limitations may still need to satisfy the underlying claim 1 formulation and dosing requirements.

The PK limitations also create proof issues. Infringement analysis would likely require comparative clinical or bioequivalence data, not merely a review of the product label. The comparison must use an equal amount of immediate-release naltrexone hydrochloride and assess the stated Cmax and AUClast parameters.

When does US Patent 9,107,837 lose exclusivity?

The nominal patent expiration date for US 9,107,837 is March 9, 2026, based on the patent family’s earliest effective nonprovisional priority date and the standard 20-year patent term. [1]

Event	Date
Patent application filed	September 26, 2014
Patent issued	August 18, 2015
Nominal expiration	March 9, 2026
Patent term extension	None identified in the patent record
Patent type	Utility patent
Product category	Small-molecule combination drug

The patent term is separate from FDA regulatory exclusivity. Contrave received three-year marketing exclusivity based on new clinical investigations supporting approval, but that exclusivity period did not extend beyond the patent term. FDA approval occurred September 10, 2014. [2,3]

A generic applicant may obtain FDA approval before patent expiration if it certifies that the listed patent is invalid, unenforceable, or will not be infringed, subject to Hatch-Waxman litigation and any resulting stay.

What is the Orange Book status of US 9,107,837?

US 9,107,837 has been associated with the Orange Book patent estate for Contrave. Orange Book listing is commercially important because it requires an ANDA applicant to address the patent through one of four certifications:

Paragraph I: no patent information is listed;
Paragraph II: the patent has expired;
Paragraph III: approval is requested after patent expiration;
Paragraph IV: the patent is invalid, unenforceable, or will not be infringed.

For a generic Contrave applicant seeking approval before March 2026, a Paragraph IV certification would be the principal route for challenging the patent. A Paragraph III certification would defer approval until the relevant patent expiry date.

The Orange Book listing does not itself establish validity or infringement. It provides the regulatory mechanism for patent certification and potential litigation under 21 U.S.C. § 355(j). [4]

Which companies are challenging the Contrave patent estate?

The relevant competitive group includes generic manufacturers that may file ANDAs for naltrexone/bupropion extended-release products. Publicly reported Contrave patent disputes have involved ANDA applicants and patent owners in federal Hatch-Waxman litigation, including challenges directed at Orexigen’s Contrave patent portfolio.

The principal patent-owning interests have changed over time:

Company or entity	Role
Orexigen Therapeutics	Original developer and patent owner
Takeda Pharmaceuticals	Former commercial partner for Contrave in the United States
Currax Pharmaceuticals	Current commercial owner and marketer of Contrave
Generic ANDA applicants	Potential Paragraph IV challengers

Patent ownership, Orange Book listing, and marketing rights are distinct. A company may acquire the NDA and commercial rights without becoming the original inventor or original applicant listed on the patent.

A complete assessment of current litigation requires review of the latest Orange Book entry, FDA Paragraph IV notices, district court dockets, Federal Circuit decisions, and settlement terms. The supplied claim text alone does not establish whether a particular generic manufacturer has an active challenge.

What patent litigation affects US 9,107,837?

The core litigation questions are likely to involve:

Whether a generic naltrexone formulation meets the claimed dissolution profile.
Whether the generic label induces treatment of overweight or obesity within the scope of the method claims.
Whether the formulation produces the required reduced adverse-effect profile.
Whether the claims are enabled across the full claimed dose and dissolution ranges.
Whether the PK limitations can be established from ANDA data.
Whether the claims are anticipated or obvious in view of earlier naltrexone, bupropion, obesity-treatment, and controlled-release disclosures.

Method-of-treatment claims can be difficult to enforce against an ANDA product when the generic label omits or narrows the patented indication. The risk increases when the label expressly instructs use for chronic weight management at the same 32 mg/360 mg daily dose and the generic product has the same release characteristics.

A settlement agreement could permit an authorized generic, a delayed generic launch, or entry before patent expiration under specified conditions. Settlement terms are often confidential or reflected only in regulatory and court filings. The patent number alone does not establish the existence or terms of a settlement.

How strong is the patent estate for US 9,107,837?

The patent has moderate strength as a formulation-specific method patent and weaker breadth than a composition-of-matter patent.

Strengths

It targets the commercial obesity indication.
It covers the full 32 mg/360 mg daily regimen.
It defines a measurable naltrexone dissolution profile.
It covers single-tablet and separate-tablet administration.
It adds PK limitations involving both naltrexone and 6-beta naltrexol.
It identifies nausea, headache, and dizziness as protected adverse-effect outcomes.

Vulnerabilities

Naltrexone and bupropion are both long-established active ingredients.
The combination and obesity-treatment concepts may face obviousness arguments.
The adverse-effect limitation may raise proof and claim-construction questions.
“About” dosage language may create boundary questions.
Claim 2’s 36 mg naltrexone alternative appears inconsistent with claim 1’s 32 mg upper limit.
Dissolution testing can vary with manufacturing conditions, analytical method, equipment, medium, and sampling.
Method claims require a connection between the accused product’s use and the claimed therapeutic result.

The strongest claims for commercial enforcement are likely claims 14 and 15 because they closely track the full commercial dosing regimen and specify the release profile, twice-daily administration, and single-unit dosage form. Claims 4 and 6 may be valuable where comparative PK data show reduced peak concentrations with preserved exposure.

What generic entry risks exist after patent expiration?

A generic launch strategy would typically fall into one of three categories:

Launch pathway	Timing	Principal risk
Paragraph III	After listed patent expiry	Delayed market entry but lower litigation exposure
Paragraph IV	Before expiry	Patent litigation, 30-month stay, possible damages
Design-around	Before or near expiry	Formulation may avoid dissolution or PK limitations but could lose clinical or regulatory equivalence

Potential design-around strategies include:

changing the naltrexone release profile;
using a different controlled-release matrix;
altering tablet composition or coating;
separating the active ingredients;
narrowing or omitting the obesity indication;
using a dosing regimen outside the asserted claims.

Separate administration alone is insufficient because claim 13 expressly covers separate oral dosage forms. Likewise, changing the tablet from a fixed-dose combination to two tablets does not avoid the patent if the dissolution, dosage, and method limitations remain satisfied.

Does biosimilar risk apply to Contrave?

No. Contrave is a small-molecule drug, not a biologic. The relevant competitive pathway is an ANDA under Section 505(j) of the Federal Food, Drug, and Cosmetic Act, not a biosimilar application under the Biologics Price Competition and Innovation Act.

The principal regulatory risks are generic substitution, Paragraph IV litigation, formulation design-around, and state substitution rules. Biosimilar interchangeability, reference-product exclusivity under the biologics statute, and biosimilar patent dance procedures do not apply.

How does US 9,107,837 compare with broader drug patents?

Patent type	Scope	Relevance to Contrave
Composition-of-matter patent	Covers the active molecule	Not available for old naltrexone or bupropion
Combination patent	Covers naltrexone plus bupropion	Broader than a release-profile claim if valid
Formulation patent	Covers controlled-release composition or dissolution	Directly relevant to US 9,107,837
Method-of-use patent	Covers treating obesity with the regimen	Directly relevant to the asserted claims
Manufacturing patent	Covers process, excipients, or tablet production	May create separate ANDA barriers
FDA exclusivity	Regulatory, time-limited approval protection	Separate from patent rights

US 9,107,837 combines formulation and method-of-treatment protection. Its commercial value depends on whether the marketed product and generic alternatives meet the precise naltrexone dissolution and dosing limitations.

Key Takeaways

US 9,107,837 covers obesity treatment using sustained-release naltrexone and sustained-release bupropion.
The central technical limitation is naltrexone release of 67% to 80% at one hour and 85% to 96% at two hours.
Claims 7, 10, and 14 require at least 99% release by eight hours.
Claims 4 and 6 add reduced Cmax and preserved AUClast requirements for naltrexone and 6-beta naltrexol.
Claims 3 and 15 cover single-unit combination products; claim 13 covers separate oral dosage forms.
Claim 14 closely tracks the Contrave full dose of 32 mg naltrexone and 360 mg bupropion daily.
The nominal expiration date is March 9, 2026.
Contrave is subject to generic, not biosimilar, competition.
The principal litigation risks concern dissolution testing, PK proof, obviousness, enablement, induced infringement, and claim scope.
Claim 2 contains a notable 36 mg naltrexone inconsistency against claim 1’s 32 mg upper limit.

FAQs

Is US 9,107,837 a composition patent?

No. It is primarily a method-of-treatment patent with formulation, dissolution, dosage, and pharmacokinetic limitations.

Does taking naltrexone and bupropion in separate tablets avoid US 9,107,837?

Not necessarily. Claim 13 expressly covers separate oral dosage forms if the remaining claim limitations are met.

What adverse effects are expressly covered?

The claims identify nausea, headache, and dizziness. Nausea is separately emphasized in claims 12 and 17.

Can a generic avoid the patent by using immediate-release naltrexone?

An immediate-release naltrexone product would likely avoid the sustained-release limitation, but it may not satisfy the FDA requirements for an equivalent generic version of Contrave and could face separate patent or regulatory issues.

Is US 9,107,837 still relevant after Contrave’s FDA exclusivity ended?

Yes. FDA marketing exclusivity and patent protection are separate. The patent can remain relevant to ANDA approval and generic launch until its expiration or successful invalidation.

References

U.S. Patent and Trademark Office. (2015). U.S. Patent No. 9,107,837, methods of treating obesity with naltrexone and bupropion.
U.S. Food and Drug Administration. (2014). FDA approves weight-management drug Contrave.
U.S. Food and Drug Administration. (2024). Drugs@FDA: Contrave, NDA 200063.
Federal Food, Drug, and Cosmetic Act, 21 U.S.C. § 355(j).
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations, commonly known as the Orange Book.

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				USE OF NALTREXONE AND BUPROPION IN EXTENDED-RELEASE FORM 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
Argentina	061233	⤷ Start Trial
European Patent Office	2061448	⤷ Start Trial
European Patent Office	3626236	⤷ Start Trial
Spain	2749800	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 9,107,837

Which drugs does patent 9,107,837 protect, and when does it expire?

Summary for Patent: 9,107,837