U.S. Patent 10,376,487: Tasimelteon Food-Effect Claims, Scope, Expiration, and Generic Risk
U.S. Patent 10,376,487 protects a specific administration regimen for tasimelteon: 20 mg orally, without food, in patients with circadian rhythm or sleep disorders. Its strongest commercial relevance is to Hetlioz and any generic product whose labeling directs patients to take tasimelteon while fasting. The patent does not claim tasimelteon as a molecule, a capsule composition, or treatment of Non-24 generally. It claims the combination of the drug, dose, patient population, and food-timing conditions.
The patent is assigned to Vanda Pharmaceuticals Inc. and issued Aug. 13, 2019. Public patent records identify a May 20, 2014 priority date, producing a nominal expiration date in 2034 before any patent-term adjustment or disclaimer is considered.[1]
What does U.S. Patent 10,376,487 claim?
The patent has two independent method claims and eighteen dependent claims.
| Claim group |
Core subject matter |
Principal limitations |
| Claim 1 |
Treatment method |
Human patient; circadian rhythm or sleep disorder; oral tasimelteon; effective dose of 20 mg/day; administration without food |
| Claims 2, 11-15 |
Food-free interval |
No food for at least 30 minutes, one hour, 1.5 hours, two hours, 2.5 hours, or three hours before administration |
| Claims 3 |
Pharmacokinetic result |
Lower Cmax and approximately unchanged AUC under fed versus fasted conditions |
| Claims 4-5 |
Disease narrowing |
Circadian rhythm disorder, specifically Non-24 Disorder |
| Claim 6 |
Pharmacokinetic treatment method |
Shortening Tmax using oral tasimelteon at 20 mg/day without food |
| Claims 7, 16-20 |
Food-free interval for Tmax method |
No food for the same intervals from 30 minutes through three hours |
| Claims 8-10 |
Pharmacokinetic and disease narrowing |
Lower Cmax, approximately unchanged AUC, circadian rhythm disorder, and Non-24 Disorder |
The patent therefore contains two related but distinct protection strategies:
- A therapeutic administration claim directed to treating the patient.
- A pharmacokinetic administration claim directed to shortening Tmax.
The claims are method-of-use claims. They require performance of the claimed administration regimen and do not cover all tasimelteon products independent of use.
How broad is the scope of claim 1?
Claim 1 is the principal treatment claim. A potentially infringing use must satisfy each of the following elements:
- The subject is a human patient.
- The patient suffers from a circadian rhythm disorder or sleep disorder.
- Tasimelteon is administered orally.
- The administered effective dose is 20 mg per day.
- The dose is administered without food.
The claim does not expressly require Non-24 Disorder. That limitation appears only in claims 4 and 5. Claim 1 can therefore reach administration to patients with other circadian rhythm disorders or sleep disorders, provided the remaining limitations are met.
The claim also does not expressly require that the patient be totally blind, although FDA approval of Hetlioz is principally associated with Non-24-Hour Sleep-Wake Disorder in adults who are totally blind. The patent claim and FDA indication are separate analytical questions. The claim may be broader than the approved indication, subject to validity, written-description, enablement, and claim-construction issues.[1][2]
What does “20 mg/d” require?
“20 mg/d” is a daily dosing limitation. It is materially narrower than a claim covering any therapeutically effective amount of tasimelteon. A regimen involving 20 mg every other day, a divided dose, or a different daily dose could create non-infringement arguments, although the practical relevance would depend on the product labeling and clinical use.
For an ANDA product, the proposed labeling would be central. A generic label that instructs patients to take 20 mg orally without food would track the core limitations of claim 1. A label that omits the food restriction may reduce literal induced-infringement exposure, but the analysis would also consider prescribing instructions, product communications, regulatory submissions, and foreseeable physician and patient use.
What does “without food” mean under the patent?
“Without food” is the central limitation in claims 1 and 6. The dependent claims progressively define the fasting interval before administration:
| Dependent claims |
Required no-food interval before dosing |
| 2 and 7 |
At least 30 minutes |
| 11 and 16 |
At least one hour |
| 12 and 17 |
At least 1.5 hours |
| 13 and 18 |
At least two hours |
| 14 and 19 |
At least 2.5 hours |
| 15 and 20 |
At least three hours |
The ordinary commercial interpretation is that the patient does not consume food during the specified pre-dose interval. The claims do not expressly specify the type, caloric content, or fat content of the prior meal. That omission may create claim-construction disputes over whether “without food” means complete fasting, absence of a meal, or a clinically meaningful period after food consumption.
The FDA label for Hetlioz states that tasimelteon should be taken without food. The label reports that a high-fat meal delays absorption and increases peak exposure while leaving overall exposure approximately unchanged.[2] That regulatory instruction aligns closely with the patent’s central food-effect limitations.
What is protected by the Tmax claims?
Claim 6 covers a method “for shortening Tmax.” It requires:
- a human patient;
- a circadian rhythm disorder or sleep disorder;
- treatment with tasimelteon;
- oral administration;
- 20 mg/day; and
- administration without food.
Claims 7 and 16-20 add the pre-dose fasting intervals. Claims 8-10 add the pharmacokinetic and disease limitations.
“Tmax” is the time required to reach maximum plasma concentration. The claim is directed to a pharmacokinetic outcome rather than only a dosing instruction. This creates two enforcement issues.
First, the patent owner would need to establish that the accused regimen is capable of producing the claimed shortening effect or that the limitation is otherwise satisfied under the governing claim construction. Second, individual patient pharmacokinetic variation may complicate proof in a particular case. A generic product may have the same active ingredient and strength but still contest whether its labeled use necessarily shortens Tmax relative to the relevant comparator.
Claims 1 and 6 are not interchangeable. Claim 1 focuses on treating the disorder. Claim 6 focuses on shortening Tmax. A defendant may challenge one claim on infringement or validity grounds without resolving the other.
How does the patent relate to the FDA-approved Hetlioz label?
Hetlioz is tasimelteon, a melatonin receptor agonist marketed by Vanda Pharmaceuticals. FDA approved Hetlioz capsules in 2014 for Non-24-Hour Sleep-Wake Disorder in adults who are totally blind.[2][3]
The label provides several facts relevant to the patent:
| Regulatory or pharmacokinetic issue |
Hetlioz information |
| Active ingredient |
Tasimelteon |
| Approved capsule strength |
20 mg |
| Administration |
Once daily before bedtime |
| Food instruction |
Take without food |
| Food effect |
High-fat meal delays absorption and raises Cmax; AUC is approximately unchanged |
| Primary approved disorder |
Non-24-Hour Sleep-Wake Disorder |
| Regulatory pathway |
New drug application |
The label substantially overlaps the limitations of claims 1, 3, 5, 6, 8, and 10. That overlap increases the risk that a generic label will be viewed as encouraging the patented method if the patent remains enforceable and listed for the relevant product.
What is the Orange Book status of U.S. Patent 10,376,487?
U.S. Patent 10,376,487 is a method-of-use patent associated with tasimelteon and Hetlioz-related intellectual property. Orange Book significance depends on whether FDA lists the patent for the specific approved product and whether the listing remains active for the relevant dosage form and indication.[3]
An Orange Book listing does not establish validity or infringement. It affects ANDA procedure. A listed patent can trigger a Paragraph IV certification and, if the NDA holder sues within the statutory period, an automatic stay of approval for up to 30 months under the Hatch-Waxman framework.[4]
The patent’s commercial effect is strongest if:
- it is listed against the relevant Hetlioz product;
- the generic applicant must certify against it;
- the proposed label includes the patented fasting instruction; and
- Vanda asserts the patent within the statutory litigation window.
The patent does not create a regulatory exclusivity period by itself. FDA exclusivity and patent rights are separate. New chemical entity exclusivity for Hetlioz expired years before the projected expiration of this patent, leaving patent and regulatory exclusivity as distinct barriers.[3][4]
When does U.S. Patent 10,376,487 expire?
The public patent record identifies a May 20, 2014 priority date and an Aug. 13, 2019 issue date.[1] On that record, the ordinary 20-year patent term is expected to run to approximately May 20, 2034, subject to:
- patent-term adjustment;
- any terminal disclaimer;
- patent-term extension;
- disclaimer or invalidation;
- maintenance-fee status; and
- correction of the official term calculation by the USPTO.
The patent should therefore be analyzed as a potential 2034 barrier, rather than as a patent expiring near the earlier composition and original-use patents covering tasimelteon.
How does the expiration compare with earlier tasimelteon patents?
| Intellectual-property category |
Typical subject matter |
Commercial role |
| Original tasimelteon patents |
Compound, composition, or core therapeutic use |
Earlier barriers, generally expiring before the food-effect patent |
| Non-24 treatment patents |
Treating Non-24 with tasimelteon |
Disease-specific protection |
| U.S. Patent 10,376,487 |
Food-free 20 mg dosing and Tmax effects |
Later method-of-use barrier tied to administration instructions |
| FDA exclusivity |
New drug regulatory exclusivity |
Expired before the later patent term |
The later expiration of the food-effect patent can matter even after earlier compound or indication patents expire. A generic may be able to market tasimelteon for an unpatented use while carving out the patented use or administration instruction, depending on the Orange Book listing and proposed label.
What Paragraph IV challenges and generic-entry risks exist?
A generic applicant seeking approval before the relevant patent expiration could file a Paragraph IV certification asserting that the patent is invalid, unenforceable, or not infringed.[4]
The principal Paragraph IV theories would likely focus on:
Infringement
A generic label that directs administration of 20 mg tasimelteon without food would closely resemble the patented method. Claims 2, 7, and 11-20 could be implicated if the label specifies a fasting interval.
A label that simply states “take without food” may not expressly recite every longer interval. Claims 1 and 6 do not require a specific numerical interval beyond the core “without food” limitation, so removing the numerical language may not avoid those independent claims.
Induced infringement
The applicant would face induced-infringement risk if the label, marketing, or regulatory materials encourage physicians or patients to perform the patented method. The label is often the central evidence in Hatch-Waxman method-of-use disputes.
Validity
Potential validity challenges include:
- anticipation by prior pharmacokinetic or food-effect studies;
- obviousness based on known food effects and the Hetlioz clinical regimen;
- lack of written description for the full range of fasting intervals;
- enablement of the claimed treatment and pharmacokinetic outcomes; and
- indefiniteness involving “without food,” “effective dose,” “approximately the same,” or “shortening Tmax.”
The food-effect claims may face an obviousness challenge if prior art taught tasimelteon administration without food and disclosed a lower Cmax or altered Tmax. Vanda’s counterargument would be that the claimed combination links a particular food restriction, 20 mg daily dose, clinical population, and pharmacokinetic profile in a way not reasonably predictable from the prior art.
How strong is the patent estate around tasimelteon?
The estate is strongest as a layered product-and-use portfolio rather than as a single patent.
| Layer |
Strength |
Main vulnerability |
| Tasimelteon active ingredient |
Potentially strong if core composition claims remain enforceable |
Earlier expiration |
| 20 mg Non-24 treatment |
Commercially important because it tracks the approved product |
Prior-art and obviousness challenges |
| Food-free administration |
Strong label overlap |
“Without food” claim construction and obviousness |
| Tmax shortening |
Differentiated technical theory |
Proof of the pharmacokinetic result |
| Formulations and dosage forms |
Relevant to capsules and liquid products |
Product-specific claim scope |
| Manufacturing claims |
May create supply-chain barriers |
Often avoidable through alternative processes |
The patent is more commercially significant for a label-aligned generic than for a generic pursuing a carefully carved-out use. Its claims do not prevent every possible tasimelteon product. They target use of the product in a specific clinical and administration context.
Are biosimilars relevant to tasimelteon?
No. Tasimelteon is a small-molecule drug, not a biologic. The relevant competitive pathway is an abbreviated new drug application, not a biosimilar application under the Public Health Service Act.[4]
The competitive issues are therefore:
- ANDA filing;
- Paragraph IV certification;
- section viii label carve-out, where available;
- 30-month litigation stay;
- patent expiration;
- FDA approval timing; and
- ability to omit the patented use or administration instruction.
What litigation and settlement issues affect the patent?
Patent litigation involving tasimelteon would likely arise through Hatch-Waxman litigation after an ANDA applicant submits a Paragraph IV certification. Relevant disputes would center on whether the generic label induces the patented administration method and whether the food-effect limitations are valid.
A settlement could include:
- a licensed entry date;
- a covenant not to sue;
- a permitted label carve-out;
- supply or licensing terms;
- acceleration provisions; or
- restrictions on launch before expiration.
A definitive assessment of any settlement requires review of the specific agreement and FTC filing, if applicable. The patent itself does not establish that a settlement exists or that any particular generic has secured a licensed entry date.
What geographic coverage does the patent provide?
U.S. Patent 10,376,487 provides rights only in the United States. It does not directly block:
- sale in Canada, Europe, Japan, or other jurisdictions;
- foreign manufacture unless U.S. importation or other U.S. conduct is implicated;
- treatment performed wholly outside the United States; or
- foreign regulatory approval.
The commercial strategy must therefore be jurisdiction-specific. Foreign counterparts, national-phase patents, prosecution outcomes, and expiration dates must be assessed separately. A U.S. method-of-use patent also may have limited leverage over overseas manufacturing that supplies non-U.S. markets.
What manufacturing and formulation barriers remain?
The patent does not claim a particular tablet, capsule, excipient system, polymorph, or manufacturing process in the claim set provided. It therefore does not independently block a manufacturer from producing a different tasimelteon formulation if that formulation is used outside the claimed regimen.
The main barriers are use-based:
- 20 mg daily administration;
- oral delivery;
- administration without food;
- treatment of the specified disorders; and
- the claimed pharmacokinetic effect.
A formulation patent, process patent, or patent covering Hetlioz LQ would need separate analysis. This patent should not be treated as a formulation patent merely because it covers administration of a dosage form.
Key Takeaways
- U.S. Patent 10,376,487 is a Vanda method-of-use patent for tasimelteon.
- Claims 1 and 6 are the independent claims.
- The core regimen is oral tasimelteon at 20 mg/day without food.
- Claims 2, 7, and 11-20 add fasting intervals from 30 minutes to three hours.
- Claims 3 and 8 require a lower Cmax with approximately unchanged AUC.
- Claims 4, 5, 9, and 10 narrow the patient population to circadian rhythm disorders and Non-24 Disorder.
- The patent closely tracks the FDA Hetlioz instruction to take tasimelteon without food.
- The public record indicates a nominal expiration around May 20, 2034, subject to the official USPTO term calculation.
- Generic risk is highest where an ANDA label repeats the fasting instruction and 20 mg regimen.
- The patent is not a biologic patent, a compound patent, or a standalone formulation patent.
- Paragraph IV litigation would likely focus on claim construction, obviousness, pharmacokinetic proof, and induced infringement.
FAQs
Can a generic sell tasimelteon after earlier patents expire but before U.S. Patent 10,376,487 expires?
Potentially, but the generic may need a label carve-out or a successful Paragraph IV challenge if the patent is listed and the proposed labeling encourages the patented use.
Does taking tasimelteon with food necessarily infringe the patent?
Not necessarily. Infringement depends on whether all claim limitations are met, including the meaning of “without food,” the dose, the patient population, and the relevant method of use.
Does the patent cover Hetlioz oral suspension?
The claims provided are not limited to capsules or suspension. They recite oral administration of tasimelteon. Product-specific formulation patents and FDA labeling for the suspension require separate analysis.
Can a physician prescribe tasimelteon for a non-24 circadian disorder without following the patented fasting interval?
The patent claims require the claimed administration condition. A use that does not satisfy “without food” may present a non-infringement position, subject to claim construction and the actual prescribing instructions.
Is the Tmax limitation likely to be easier to enforce than the treatment limitation?
Not necessarily. The Tmax claim is technically differentiated but may require stronger pharmacokinetic evidence. The treatment claim is broader in clinical purpose but depends on proving the administration and dosing limitations.
References
- United States Patent and Trademark Office. (2019). U.S. Patent No. 10,376,487, Methods of treating circadian rhythm disorders. https://patents.google.com/patent/US10376487B2/en
- U.S. Food and Drug Administration. (2024). Hetlioz (tasimelteon) prescribing information. https://www.accessdata.fda.gov/drugsatfda_docs/label/
- U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations, Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/
- Federal Food, Drug, and Cosmetic Act, 21 U.S.C. § 355(j). (2024). https://www.law.cornell.edu/uscode/text/21/355
