United States Patent 10,610,511: Tasimelteon Food-Effect Claims, Scope and Patent Landscape
US Patent 10,610,511 protects instructions to administer tasimelteon without food, including fasting periods of at least 30 minutes to three hours before dosing. The patent does not claim tasimelteon as a chemical compound, a formulation, or a manufacturing process. Its commercial value is concentrated in method-of-use enforcement against generic applicants whose proposed labels instruct patients to take tasimelteon under fasting conditions.
The claims are directed primarily to 20 mg once-daily tasimelteon treatment for Non-24-Hour Sleep-Wake Disorder and other circadian or sleep disorders. The patent is closely tied to the food-effect information in the FDA labeling for Hetlioz.
What does US Patent 10,610,511 protect?
The patent protects a treatment protocol with two required components:
- A healthcare provider or other actor instructs the patient to take tasimelteon without food.
- The patient orally receives an effective dose of tasimelteon without food.
Independent claims 1 and 18 are the principal infringement claims. Claim 12 is an improvement claim that assumes an existing regimen of 20 mg once daily before a target bedtime.
| Claim group |
Core limitation |
Commercial significance |
| Claims 1-10 |
Treating a circadian or sleep disorder with tasimelteon without food |
Broadest method-of-use coverage |
| Claim 3 |
Lower Cmax and approximately unchanged AUC under fed versus fasted conditions |
Pharmacokinetic limitation |
| Claims 4-5 |
Circadian rhythm disorder, including Non-24 Disorder |
Principal approved-indication coverage |
| Claims 6-10 |
No food for at least one to three hours before administration |
Graduated fasting limitations |
| Claim 11 |
Effective dose of 20 mg per day |
Matches the standard Hetlioz dose |
| Claims 12-17 |
Improvement to a 20 mg once-daily regimen before target bedtime |
Targets label-based generic substitution |
| Claim 18 |
Instruction and administration without food |
Duplicative broad independent method |
| Claim 19 |
Effective dose of 20 mg per day |
Narrows claim 18 to the commercial dose |
The patent is therefore a regimen patent. It does not prevent a competitor from manufacturing tasimelteon in the abstract. It creates infringement risk when the competitor sells or labels tasimelteon for use with the claimed fasting instructions.
How broad are the independent claims?
Claim 1
Claim 1 requires:
- a human patient;
- a circadian rhythm disorder or sleep disorder;
- an instruction that tasimelteon should be taken without food;
- oral administration of an effective dose;
- administration without food.
The claim does not expressly require:
- 20 mg;
- once-daily dosing;
- administration before bedtime;
- Non-24 Disorder;
- a specific dosage form;
- a particular fasting interval;
- a measurable pharmacokinetic outcome.
This gives claim 1 substantial breadth within the therapeutic-use field. A product label directing patients to take tasimelteon on an empty stomach could satisfy the instruction limitation even if the label does not reproduce the patent’s exact wording.
Claim 18
Claim 18 is similar to claim 1 but places the instruction before administration in the claim language. It also does not require a 20 mg dose unless claim 19 is asserted.
The practical distinction between claims 1 and 18 is limited. Both focus on the same conduct: instructing a patient to take tasimelteon without food and administering the drug under fasting conditions. The presence of two similar independent claims gives the patent holder alternative claim formats in litigation.
Claim 12
Claim 12 is narrower and more closely aligned with the commercial Hetlioz regimen. It requires:
- treatment of a circadian rhythm or sleep disorder;
- oral administration of 20 mg per day;
- once-daily dosing;
- administration before a target bedtime;
- an instruction to take tasimelteon without food;
- no food for at least 30 minutes before administration.
Claim 12 may be important where a generic applicant adopts the same dose and bedtime regimen as the branded product but attempts to distinguish its label from the broader claims.
What do the fasting-period claims cover?
Claims 2 and 6-10 establish a series of minimum fasting periods:
| Claim |
Minimum period without food before administration |
| Claim 2 |
30 minutes |
| Claim 6 |
1 hour |
| Claim 7 |
1.5 hours |
| Claim 8 |
2 hours |
| Claim 9 |
2.5 hours |
| Claim 10 |
3 hours |
These claims are cumulative limitations. A three-hour fasting interval would generally fall within the one-hour, 1.5-hour, two-hour, 2.5-hour and three-hour limitations, assuming the other claim requirements are met.
The claims do not expressly require the patient to remain fasting after dosing. They focus on the period before administration. The phrase "with no food" in the independent claims could generate claim-construction disputes, but the dependent claims clarify that the relevant fasting period is principally pre-dose.
The patent also does not define "food" in the claims. Product labeling, clinical protocols and expert testimony would likely become relevant in determining whether a particular beverage, snack, nutritional product or meal satisfies the limitation.
What does claim 3 add to the patent scope?
Claim 3 requires that:
- Cmax is lowered when tasimelteon is administered under fed conditions compared with fasted conditions; and
- AUC is approximately the same under fed and fasted conditions.
This is a pharmacokinetic limitation rather than a conventional dosing instruction. It reflects the distinction between exposure over time, measured by AUC, and peak concentration, measured by Cmax.
The limitation has two effects:
- It links the claim to the clinical rationale for administering tasimelteon without food.
- It may narrow infringement and validity disputes because the parties would need to address pharmacokinetic evidence, assay methods, statistical variation and the meaning of "approximately the same."
A generic applicant could challenge whether the pharmacokinetic result is an enforceable claim limitation or merely an inherent consequence of the administration method. The answer would depend on the intrinsic patent record, prosecution history and applicable claim-construction law.
What indication and dosage are covered?
The claims cover both circadian rhythm disorders and sleep disorders. Claim 5 specifically identifies Non-24 Disorder, the principal disease area associated with Hetlioz.
The commercial center of gravity is the 20 mg once-daily regimen:
- Claims 11 and 19 expressly require 20 mg per day.
- Claim 12 independently requires 20 mg per day and once-daily administration.
- Claims 1 and 18 can cover an effective dose without expressly limiting the dose to 20 mg.
The claims are not limited to capsules. They recite oral administration, which can potentially encompass different oral dosage forms if the other limitations are satisfied. A change from capsule to tablet, oral suspension or another oral form would not necessarily avoid the method claims.
What is the FDA regulatory status of tasimelteon?
Tasimelteon is marketed by Vanda Pharmaceuticals as Hetlioz. The FDA approved Hetlioz for Non-24-Hour Sleep-Wake Disorder in totally blind adults in 2014. The FDA later approved Hetlioz for nighttime sleep disturbances in Smith-Magenis syndrome.
The FDA-approved labeling instructs patients to take Hetlioz without food and before bedtime. The labeling reports that food increases tasimelteon exposure metrics, including Cmax, while the overall exposure measured by AUC is not materially changed. This labeling is directly relevant to the scope and commercial importance of US Patent 10,610,511. [1]
The food instruction is not merely a patent-created direction. It is part of the FDA-approved use information. That increases the risk that an ANDA applicant will need to address the patent through a Paragraph IV certification or a section viii label carve-out analysis.
What is the Orange Book status of US Patent 10,610,511?
US Patent 10,610,511 is associated with the Hetlioz patent estate and is relevant to the product’s method-of-use exclusivity. Orange Book listing status should be assessed separately for each approved dosage form and indication because FDA patent listings can differ by product presentation and use code. [2]
The patent’s earliest priority and filing history place its baseline patent term in the 2033 period, subject to any applicable patent-term adjustment. The operative enforceability date should be taken from the USPTO patent record and Orange Book entry rather than inferred solely from the grant date. [3]
The patent term is materially later than the original approval-related exclusivity period. As a result, the principal post-exclusivity barrier is patent enforcement rather than FDA new-drug exclusivity.
When does tasimelteon lose exclusivity?
Tasimelteon has several distinct exclusivity layers:
| Exclusivity layer |
Relevance to Hetlioz |
| FDA regulatory exclusivity |
Separate from patent term and generally expires earlier than the asserted method patent |
| Composition and formulation patents |
May cover the active ingredient, dosage form or product presentation |
| Method-of-use patents |
Include the food-effect and dosing-regimen claims in US 10,610,511 |
| Pediatric exclusivity |
Applies only if granted for a qualifying product and period |
| Patent-term adjustment |
Can extend the ordinary 20-year term |
| Litigation stay |
A Paragraph IV lawsuit can delay FDA approval for up to 30 months, subject to statutory exceptions |
The practical generic-entry date depends on the full Orange Book patent set, any Paragraph IV notice, litigation outcomes, settlement terms and the generic applicant’s proposed label. A patent expiration date alone does not establish the earliest lawful commercial launch date.
Which companies are likely to challenge the Hetlioz patent estate?
Generic applicants seeking approval for tasimelteon could challenge the estate through:
- Paragraph IV certifications alleging invalidity, unenforceability or noninfringement;
- section viii statements carving out patented methods from the proposed label;
- litigation over whether the generic label induces the claimed fasting method;
- post-grant or inter partes review proceedings, where statutory requirements are met.
The most significant risk concerns a generic label that reproduces the FDA-approved instruction to take tasimelteon without food. A label that omits the fasting instruction may reduce method-of-use exposure but could create regulatory and therapeutic-substitution issues if the FDA-approved labeling requires the instruction for safe or effective use.
A section viii strategy is difficult where the patented method is embedded in the approved use and dosing instructions. The outcome would depend on the use code, the complete Orange Book listing and the exact proposed labeling.
What patent litigation affects tasimelteon?
Tasimelteon has been the subject of patent disputes involving Vanda’s Hetlioz patent estate and generic applicants. The relevant disputes have centered on method-of-use patents, including patents covering treatment of Non-24 Disorder and administration conditions.
For US 10,610,511, the likely litigation issues include:
- Whether the proposed generic label instructs fasting administration.
- Whether a patient’s conduct can be attributed to the generic manufacturer.
- Whether "without food" and the specified fasting intervals are definite.
- Whether the claims are anticipated or obvious in view of prior tasimelteon clinical and pharmacokinetic information.
- Whether the claimed food-effect regimen produces an unexpected clinical or pharmacokinetic result.
- Whether the generic label can omit the patented instruction while remaining adequate under the FDA’s labeling requirements.
A complete litigation assessment requires reviewing the current PACER docket, Federal Circuit decisions, district court judgments and any settlement agreement. The patent record alone does not establish whether a particular defendant has settled, launched at risk or obtained a judgment of noninfringement.
How strong is the patent estate for US 10,610,511?
The patent has meaningful commercial strength but narrower technical coverage than a composition-of-matter patent.
Strengths
- The claims track the FDA-approved fasting instruction.
- Claims 1 and 18 are broad method claims.
- Claims 11, 12 and 19 track the marketed 20 mg regimen.
- The dependent claims provide multiple fallback fasting intervals.
- The patent can create inducement risk even where the generic product is chemically identical.
- The food-effect disclosure provides a pharmacokinetic rationale for the claimed administration method.
Vulnerabilities
- The claims are directed to a known drug and a dosing condition, making obviousness a central risk.
- "Without food" may be challenged as indefinite or insufficiently precise depending on the intrinsic record.
- The claimed fasting intervals may be attacked as routine optimization.
- Claim 3 may face disputes over the meaning of "lowered" and "approximately the same."
- Method-of-use enforcement requires proving the defendant’s label, marketing or other conduct leads to the claimed patient behavior.
- A generic applicant may attempt a label carve-out that excludes the patented use.
The estate is stronger against a generic label that copies the branded fasting instruction than against a product sold with no fasting direction and no promotion of the patented method.
How does this patent compare with composition and formulation patents?
US 10,610,511 differs from traditional pharmaceutical patent categories:
| Patent type |
What it protects |
Relevance to tasimelteon |
| Composition patent |
The chemical compound or salt |
Potentially blocks all uses and formulations |
| Formulation patent |
Excipients, release profile or dosage form |
Can block a particular product design |
| Manufacturing patent |
Synthetic route or purification process |
May impose production barriers |
| Method-of-use patent |
Administration for a disease or under specified conditions |
US 10,610,511 |
| Food-effect patent |
Administration relative to meals or fasting |
The principal focus of US 10,610,511 |
A method patent generally has less absolute blocking power than a valid composition patent. Its value depends on the overlap between the patented method and the FDA-approved label.
Is biosimilar risk relevant to tasimelteon?
No. Tasimelteon is a small-molecule drug, not a biologic. Biosimilar approval under the Public Health Service Act is not the relevant pathway.
The competitive threat is an ANDA generic or, potentially, an application under another small-molecule pathway. The relevant legal mechanisms are Paragraph IV certification, section viii labeling and Hatch-Waxman litigation.
What generic launch scenarios exist?
Scenario 1: Label-copying generic
The generic label includes the instruction to take tasimelteon without food. This creates the highest infringement risk and is the most likely basis for a Paragraph IV dispute involving US 10,610,511.
Scenario 2: Section viii carve-out
The applicant removes the patented fasting instruction while retaining non-patented indications or dosing information. This may reduce infringement risk, but FDA approval depends on whether the carved-out labeling remains adequate.
Scenario 3: At-risk launch
A generic launches before final resolution of patent litigation. This exposes the applicant to damages, an injunction and potential market disruption.
Scenario 4: Post-expiration launch
The applicant waits for expiry or a settlement date. This reduces litigation risk but may sacrifice first-to-market economics.
Key Takeaways
- US Patent 10,610,511 is a method-of-use patent covering fasting administration of tasimelteon.
- Claims 1 and 18 provide the broadest coverage; claims 12 and 19 target the commercial 20 mg regimen.
- Claims 2 and 6-10 create fasting-period fallbacks from 30 minutes through three hours.
- Claim 3 adds a pharmacokinetic limitation involving reduced Cmax and approximately unchanged AUC.
- The patent does not claim tasimelteon’s chemical structure, formulation or manufacturing process.
- The principal infringement risk is a generic label that instructs patients to take tasimelteon without food.
- Tasimelteon is a small molecule, so biosimilar competition is not relevant.
- Orange Book status, litigation outcomes and settlement terms control the practical generic-entry analysis.
- The patent’s baseline term extends into the 2033 period, subject to the official USPTO and Orange Book term data.
- The estate is commercially significant because the patented instruction is aligned with FDA-approved Hetlioz labeling.
FAQs
Can a generic sell tasimelteon if it removes the fasting instruction?
Potentially, but approval and infringement risk depend on the remaining label, the applicable Orange Book use code and whether the generic company promotes or induces the patented method outside the label.
Does taking tasimelteon with a light snack avoid US Patent 10,610,511?
Not necessarily. The claims do not define a quantitative food threshold. Whether a snack qualifies as "food" would depend on the claim language, specification, prosecution history and evidence concerning the patient’s conduct.
Does US Patent 10,610,511 cover tasimelteon oral suspension?
Potentially. The claims require oral administration but do not expressly limit the dosage form to a capsule. An oral suspension could fall within the claims if the other limitations are satisfied.
Can the patent be challenged through inter partes review?
Potentially. A petitioner could seek inter partes review based on qualifying printed prior art, although the availability and strategic value of that route depend on statutory timing and the asserted grounds.
Does FDA approval of a generic automatically eliminate the patent risk?
No. FDA approval and patent freedom to operate are separate questions. A generic can receive approval while remaining subject to a patent settlement, launch restriction, damages claim or injunction.
References
- U.S. Food and Drug Administration. (2024). Hetlioz (tasimelteon) prescribing information. FDA.
- U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.
- United States Patent and Trademark Office. (2020). U.S. Patent No. 10,610,511, Methods of treating circadian rhythm disorders. USPTO.
- U.S. Food and Drug Administration. (2014). FDA approves Hetlioz to treat Non-24-hour sleep-wake disorder. FDA.
- Vanda Pharmaceuticals Inc. (2024). Annual report on Form 10-K. U.S. Securities and Exchange Commission.
