United States Patent 11,285,118: Claim Scope, Auvelity Exclusivity, and Dextromethorphan-Bupropion Patent Landscape
United States Patent No. 11,285,118 protects a pharmacokinetic method for increasing dextromethorphan exposure by co-administering dextromethorphan with bupropion for at least eight days. The claims are directed to specified dose ranges, dosing frequency, patient metabolic status, and day-eight pharmacokinetic results.
The patent is relevant to Auvelity, Axsome Therapeutics’ extended-release dextromethorphan hydrobromide-bupropion hydrochloride product approved for major depressive disorder. Its strongest commercial relevance is as a method-of-use and pharmacokinetic patent. It does not, based on the supplied claims, broadly claim every dextromethorphan-bupropion product or every use of the combination.
What does United States Patent 11,285,118 cover?
Patent 11,285,118 covers a method of increasing dextromethorphan plasma levels in a human who is initially a non-poor metabolizer of dextromethorphan.
The independent claim requires all of the following:
| Claim limitation |
Requirement |
| Active agents |
Bupropion plus dextromethorphan |
| Bupropion amount |
About 50 mg to about 220 mg bupropion hydrochloride, or molar equivalent |
| Dextromethorphan amount |
About 40 mg to about 60 mg dextromethorphan hydrobromide, or molar equivalent |
| Dosing frequency |
Once daily or twice daily |
| Treatment duration |
At least eight consecutive days |
| Patient population |
Human being who is a non-poor metabolizer of dextromethorphan |
| Pharmacokinetic result |
Day-eight dextromethorphan Cavg about 20 to about 1,000 times higher than 60 mg dextromethorphan alone |
| Comparator |
Eight consecutive days of 60 mg dextromethorphan hydrobromide without bupropion |
The patent therefore combines composition-of-matter quantities with a pharmacokinetic outcome. A competing product could contain the same two active ingredients but avoid infringement if it does not satisfy one or more required limitations, subject to the actual product label, clinical use, and infringement theory.
How narrow are the independent claims?
Claim 1 is broad in numerical range but narrow in cumulative requirements. Its scope is restricted by:
- The requirement for at least eight consecutive days of treatment.
- The non-poor-metabolizer patient limitation.
- The requirement for once-daily or twice-daily administration.
- Specific dose ranges for both ingredients.
- A relative Cavg result measured against a defined dextromethorphan-only regimen.
The Cavg limitation is particularly important. A generic or alternative product would not necessarily infringe merely because bupropion inhibits CYP2D6 and increases dextromethorphan exposure. The claimed pharmacokinetic ratio must be met, or infringement would need to proceed under a different claim or legal theory.
The comparator is also material. The claim does not compare exposure against placebo or baseline. It compares day-eight exposure from the combination against exposure from 60 mg dextromethorphan hydrobromide administered without bupropion for eight consecutive days.
What do dependent claims 2 through 20 add?
The dependent claims narrow the pharmacokinetic and therapeutic scope.
| Claims |
Added limitation |
| 2 |
Cavg increase limited to about 20 to about 60 times |
| 3 |
Bupropion narrowed to about 70 mg to about 150 mg |
| 4 |
Day-eight Cmax of about 75 ng/mL |
| 5 |
Day-eight Cmax of about 70 ng/mL to about 90 ng/mL |
| 6 |
About 105 mg bupropion with about 44 mg to about 46 mg dextromethorphan |
| 7, 11, 15 |
Treatment of depression |
| 8, 12, 16 |
Treatment of nicotine addiction |
| 9, 13, 17 |
Treatment of agitation associated with Alzheimer’s disease |
| 10 |
Day-eight Cmax of at least about 70 ng/mL |
| 14 |
Cmax of about 70 ng/mL to about 90 ng/mL |
| 18 |
At least 14 consecutive days |
| 19 |
At least 30 consecutive days |
| 20 |
Conversion to poor-metabolizer status by day eight |
Claim 6 is commercially significant because it identifies approximately 105 mg of bupropion with approximately 45 mg of dextromethorphan. That dosing relationship is close to the active-ingredient quantities associated with Auvelity’s approved regimen, although product-strength comparisons must account for formulation, salt form, release characteristics, and labeled administration.
Does Patent 11,285,118 cover Auvelity?
Patent 11,285,118 is directed to pharmacokinetic and method-of-use characteristics that are closely associated with the dextromethorphan-bupropion combination used in Auvelity.
Auvelity contains dextromethorphan hydrobromide and bupropion hydrochloride in extended-release tablets. The FDA-approved labeling provides for one tablet once daily for the first three days, followed by one tablet twice daily, with a maximum of two tablets per day. Each tablet contains 45 mg dextromethorphan hydrobromide and 105 mg bupropion hydrochloride.[1]
The patent claims cover those nominal active-ingredient amounts through claims requiring approximately 105 mg bupropion and approximately 44 mg to 46 mg dextromethorphan. Claims 7, 11, and 15 also reach treatment of depression when the pharmacokinetic limitations are satisfied.
Coverage is not determined solely by matching milligram amounts. A product or use must also satisfy the duration, dosing-frequency, patient-metabolizer, and pharmacokinetic limitations. FDA approval and patent infringement are separate legal questions.
What is the likely patent expiration date?
The patent’s term is governed by the earliest effective nonprovisional filing in its priority chain, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and other USPTO calculations.
The patent is generally associated with the dextromethorphan-bupropion development program initiated in the 2013-2014 period. On that basis, the ordinary U.S. patent term is expected to fall in the mid-2030s, subject to the official USPTO term calculation and any applicable adjustment.
| Item |
Assessment |
| Patent |
US 11,285,118 |
| Grant date |
March 29, 2022 |
| Technology |
Dextromethorphan-bupropion pharmacokinetic method |
| Commercial product relevance |
Auvelity |
| Expected ordinary term window |
Approximately 2034, subject to official term adjustment |
| Regulatory exclusivity |
Separate from patent term |
| Orange Book impact |
Depends on FDA-listed patent status and approved-use correspondence |
Patent expiration should not be equated with the end of all Auvelity exclusivity. Other listed patents, regulatory exclusivity, pediatric exclusivity, or later-issued patents may affect generic entry.
What is the Orange Book status of Patent 11,285,118?
FDA Orange Book listing must be evaluated against the specific approved product and the patent-use code submitted by the NDA holder. A patent can be relevant to an approved drug without covering the drug’s active ingredient in the classic composition-of-matter sense.
For Auvelity, the commercially important patent categories include:
- Combination-product patents.
- Formulation and extended-release patents.
- Pharmacokinetic patents.
- Method-of-use patents for major depressive disorder and other central-nervous-system indications.
- Manufacturing or solid-state patents, if listed or asserted.
Patent 11,285,118 is best characterized as a method and pharmacokinetic patent. Its practical Orange Book value depends on whether the listed use code corresponds to the approved depression indication and whether a generic applicant’s proposed label would practice the claimed method.
A Paragraph IV certification against this patent would typically require the applicant to assert that the patent is invalid, unenforceable, or will not be infringed. A proper induced-infringement analysis would examine the proposed labeling and whether the label directs use that meets the claimed dosing and duration conditions.
How strong is the patent estate around dextromethorphan-bupropion?
The estate is stronger as a layered commercial portfolio than as a single-patent barrier. Patent 11,285,118 does not independently block every generic formulation. Its value increases when combined with other patents covering the product, dosage form, approved use, and release profile.
Core patent layers
| Patent layer |
Commercial function |
Primary vulnerability |
| Combination claims |
Protect use of dextromethorphan with bupropion |
Prior-art combination and obviousness challenges |
| Pharmacokinetic claims |
Protect exposure profile and metabolic conversion |
Written description, enablement, inherency, and measurement disputes |
| Formulation claims |
Protect extended-release delivery |
Design-around using different release architecture |
| Method-of-use claims |
Protect depression and other CNS uses |
Skinny-label and divided-infringement issues |
| Manufacturing claims |
Protect production process or product attributes |
Alternative process and noninfringement defenses |
The supplied claims contain several litigation pressure points:
- Whether “non-poor metabolizer” is sufficiently definite.
- Whether the Cavg ratio is reproducible across assay methods and patient populations.
- Whether the specification supports the full 20-fold to 1,000-fold range.
- Whether the claimed pharmacokinetic result is inherent in routine co-administration.
- Whether the claims are obvious in view of known CYP2D6 inhibition by bupropion.
- Whether the claims improperly rely on a result rather than a structurally defined product or treatment protocol.
- Whether the approved product’s dosing instructions necessarily practice every limitation.
What Paragraph IV challenges could target this patent?
A generic applicant could challenge Patent 11,285,118 through several theories.
Anticipation
The challenger would need a single prior-art reference disclosing every claim limitation, including:
- The specified bupropion and dextromethorphan amounts.
- Once-daily or twice-daily administration.
- At least eight days of treatment.
- A non-poor metabolizer population.
- The claimed day-eight Cavg relationship.
- Any additional Cmax or treatment indication limitation in the dependent claims.
The pharmacokinetic result may make anticipation difficult unless an earlier clinical study disclosed the same regimen and exposure values.
Obviousness
Obviousness is likely to be the more substantial challenge. Prior art may have disclosed:
- Dextromethorphan as a CNS-active agent.
- Bupropion as a CYP2D6 inhibitor.
- Combination use of the two compounds.
- Use of the combination for depression or other CNS disorders.
- Extended-release formulations.
- Clinical dosing within or near the claimed ranges.
The patent owner would likely rely on the magnitude, duration, and predictability of the exposure increase, along with clinical tolerability and therapeutic performance.
Written description and enablement
Claims spanning Cavg increases from approximately 20 times to approximately 1,000 times create a broad numerical range. A challenger could argue that the patent specification does not demonstrate or enable the full range across all claimed doses, schedules, salts, and patient populations.
Claims 4, 5, 10, and 14 create a narrower defense position because they focus on Cmax values around 70 to 90 ng/mL. Narrow claims may be more resilient if supported by clinical pharmacokinetic data, but they can also be vulnerable if the values are viewed as routine results of dose optimization.
What generic launch scenarios exist?
The principal generic-entry scenarios are as follows.
Scenario 1: Paragraph III certification
A generic applicant accepts the patent’s validity and infringement position and agrees not to market until patent expiry. This produces no early-entry litigation but preserves the patent barrier through its remaining term.
Scenario 2: Paragraph IV certification with litigation
The applicant alleges invalidity, unenforceability, or noninfringement. If the NDA holder sues within the statutory period, FDA approval may be subject to a 30-month stay, subject to court and regulatory developments.[2]
Scenario 3: Carve-out or skinny label
The applicant removes a patented indication from its labeling. This strategy is less effective if the remaining label still instructs the claimed dosing regimen for an unpatented use or if the patent’s claims are broad enough to cover the approved product’s general administration.
Scenario 4: Formulation design-around
A competitor could attempt to use different release kinetics, different tablet strengths, a different salt, or separate administration. The patent expressly reaches molar equivalents of alternative salt and free-base forms, reducing the usefulness of a simple salt substitution.
Scenario 5: Noninfringing exposure profile
A competitor could alter dose, dosing interval, treatment duration, or formulation to avoid the claimed day-eight Cavg or Cmax limitations. This approach could affect bioequivalence, clinical utility, and FDA approval.
What manufacturing and formulation barriers remain?
The claims are not limited to a named commercial brand or a single tablet architecture. They expressly recognize bupropion free base and other salt forms, as well as dextromethorphan free base and other salt forms, through molar-equivalence language.
That language limits a salt-form design-around. It does not necessarily eliminate all formulation strategies. Potential distinctions may include:
- Different release mechanisms.
- Separate dosage forms administered together.
- Different dosing schedules.
- Different active-ingredient ratios.
- Use outside the claimed day-eight exposure range.
- A product that does not direct treatment for a claimed indication.
A competitor must also consider product-specific patent claims not reproduced here. A formulation design-around that avoids Patent 11,285,118 may still infringe a separate extended-release, tablet, process, or method-of-use patent.
How does Patent 11,285,118 compare with ordinary dextromethorphan or bupropion products?
| Product or approach |
Dextromethorphan |
Bupropion |
Main patent issue |
| Dextromethorphan-only product |
Yes |
No |
Does not satisfy combination limitation |
| Bupropion-only product |
No |
Yes |
Does not satisfy combination limitation |
| Immediate co-administration |
Yes |
Yes |
May satisfy combination, but pharmacokinetic and duration limitations remain |
| Auvelity-type regimen |
Yes |
Yes |
Closest commercial match to the claimed ranges |
| Different dose or interval |
Yes |
Yes |
May avoid literal infringement if exposure and schedule limitations are not met |
| Different salts at molar-equivalent doses |
Yes |
Yes |
Salt substitution alone may not avoid the claims |
| Different CNS indication |
Yes |
Yes |
Claims 1-6 may remain relevant even if claims 7-17 are avoided |
What is the litigation and licensing outlook?
The principal commercial dispute would likely center on generic challenges to the Auvelity patent portfolio rather than licensing of Patent 11,285,118 alone. A settlement could provide a defined generic launch date, an authorized-generic arrangement, or other market terms.
Publicly assessing a settlement requires an identified case, docket, or agreement. Patent 11,285,118 should therefore be analyzed as one component of the broader Axsome dextromethorphan-bupropion portfolio. A challenge that defeats this patent may not establish freedom to launch if other Orange Book-listed or non-listed patents remain enforceable.
Key Takeaways
- Patent 11,285,118 is a pharmacokinetic and method-of-use patent, not a broad claim to dextromethorphan or bupropion individually.
- Claim 1 requires co-administration, defined dose ranges, at least eight days of treatment, a non-poor-metabolizer patient, and a day-eight Cavg increase.
- Claims 6 and 7 are commercially important because they connect approximately 105 mg bupropion, approximately 45 mg dextromethorphan, and depression treatment.
- The patent is closely relevant to Auvelity’s active ingredients and dosing architecture.
- The principal validity issues are obviousness, enablement across the broad pharmacokinetic ranges, written description, and reproducibility of Cavg and Cmax results.
- Salt substitution alone is unlikely to provide a reliable design-around because the claims include molar-equivalent salt and free-base forms.
- Generic entry will depend on the full Orange Book portfolio, not Patent 11,285,118 in isolation.
- The patent’s ordinary term is expected to extend into approximately 2034, subject to the official USPTO patent-term calculation and any applicable adjustments.
Frequently Asked Questions
Does Patent 11,285,118 claim Auvelity itself?
No. The supplied claims claim methods of co-administering bupropion and dextromethorphan that produce specified pharmacokinetic results. Separate patents may claim the product, formulation, release profile, or other uses.
Can a generic avoid infringement by using a different bupropion salt?
Not necessarily. The claims expressly cover molar-equivalent amounts of bupropion free base and other salt forms. The generic would need to assess all limitations, not only the salt identity.
Is the eight-day treatment period required for infringement?
For claim 1, yes. The method requires once-daily or twice-daily co-administration for at least eight consecutive days. Claims 18 and 19 impose longer minimum periods for certain narrower claim paths.
Does a depression indication automatically infringe?
No. Depression treatment is a limitation in claims 7, 11, and 15, but those claims also incorporate the underlying dose, duration, metabolic, and pharmacokinetic limitations.
Does expiration of Patent 11,285,118 guarantee generic Auvelity entry?
No. Other patents, regulatory exclusivity, litigation outcomes, formulation rights, and additional patent claims may delay or restrict launch.
References
- U.S. Food and Drug Administration. (2022). Auvelity (dextromethorphan hydrobromide and bupropion hydrochloride) prescribing information.
- U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
- United States Patent and Trademark Office. (2022). United States Patent No. 11,285,118.
- U.S. Food and Drug Administration. (2024). Submitting patent information and certifications under the Hatch-Waxman Act.
