United States Patent 7,365,205: Edoxaban Claim Scope, Orange Book Status, Expiration and Generic Risk
U.S. Patent No. 7,365,205 protects edoxaban, including its p-toluenesulfonate salt and p-toluenesulfonate monohydrate. The marketed U.S. product, Savaysa, contains edoxaban tosylate monohydrate. Claim 6 is the most direct product claim against the commercial active pharmaceutical ingredient because it recites the specific stereochemical form, tosylate salt and monohydrate.
The patent was assigned to Daiichi Sankyo Co., Ltd. It issued on April 29, 2008, from an application claiming priority to Japanese filings made in 2002. Its ordinary patent term would have expired in 2023, but the patent received a patent-term extension associated with FDA regulatory review. The commonly reported extended expiration date is June 22, 2026.[1][2]
What drug does U.S. Patent 7,365,205 protect?
The patent protects edoxaban, an oral, direct factor Xa inhibitor marketed in the United States as Savaysa and in other markets primarily as Lixiana. The commercial product is edoxaban tosylate monohydrate.
The chemical structure in the claims contains four principal structural elements:
- A 5-chloropyridin-2-yl substituent.
- An ethanediamide linker.
- A substituted cyclohexane ring bearing a dimethylcarboxamide group.
- A 5-methyl-4,5,6,7-tetrahydrothiazolo[5,4-c]pyridine carboxamide group.
The claimed molecule is not a generic factor Xa inhibitor genus. It is a specific small-molecule compound, with additional claims directed to defined stereochemistry, the tosylate counterion and the monohydrate solid form.
| Patent |
U.S. 7,365,205 |
| Assignee |
Sankyo Co., Ltd., now associated with Daiichi Sankyo |
| Issue date |
April 29, 2008 |
| Technology |
Direct factor Xa inhibitor |
| Active ingredient |
Edoxaban |
| Commercial salt |
Edoxaban tosylate |
| Commercial solid form |
Edoxaban tosylate monohydrate |
| FDA product |
Savaysa, NDA 206316 |
| FDA approval |
January 8, 2015 |
| Original nominal expiration |
June 22, 2023 |
| Reported PTE-adjusted expiration |
June 22, 2026 |
| Core commercial relevance |
Direct product protection for Savaysa API |
What does claim 1 of U.S. Patent 7,365,205 cover?
Claim 1 covers the named edoxaban chemical entity and “a salt thereof.”
Its scope has two important characteristics.
First, the claim identifies the compound by a precise chemical structure rather than by a broad Markush formula. A competing compound with a different heterocycle, substituent or ring substitution pattern would generally fall outside the literal chemical-entity definition.
Second, the claim does not expressly specify the 1S,2R,4S stereochemical configuration. Read literally, the absence of stereochemical descriptors creates broader coverage than the later stereospecific claims. Claim 1 therefore potentially reaches stereochemical forms of the recited constitutional structure, subject to claim construction, written-description support and any applicable limitations arising from the patent specification.
The phrase “a salt thereof” extends the claim beyond the free base. It is directed to salts formed from the claimed edoxaban molecule. Claim 1 does not limit the counterion to p-toluenesulfonate.
A generic applicant seeking approval for edoxaban tosylate monohydrate would face a direct infringement theory under claim 1 if the claim remains valid and enforceable through the relevant launch date.
What do claims 2 and 3 protect?
Claims 2 and 3 narrow the salt and hydration state.
| Claim |
Subject matter |
Commercial relevance |
| 2 |
Edoxaban p-toluenesulfonate |
Covers the tosylate salt without expressly requiring the monohydrate |
| 3 |
Edoxaban p-toluenesulfonate monohydrate |
Covers the specific salt and hydration state used commercially |
Claim 2 is a salt-form claim. It is narrower than claim 1 because it limits the counterion to p-toluenesulfonate, but it does not require the stereochemical configuration recited in claims 4-6.
Claim 3 adds the monohydrate. A product made with edoxaban tosylate monohydrate would fall within the express subject matter of claim 3 if the claim is valid and the product has the claimed composition.
The commercial value of claim 3 is substantial because a generic company cannot avoid it merely by using the same active moiety in the same salt form while changing ordinary manufacturing parameters. It would need to demonstrate that its product is not the claimed monohydrate, invalidate the claim or rely on a noninfringing alternative.
What do claims 4, 5 and 6 protect?
Claims 4-6 recite the defined stereochemical form, identified as (1S,2R,4S).
| Claim |
Subject matter |
Scope |
| 4 |
(1S,2R,4S)-edoxaban and a salt thereof |
Stereospecific compound and salts |
| 5 |
(1S,2R,4S)-edoxaban p-toluenesulfonate |
Stereospecific tosylate salt |
| 6 |
(1S,2R,4S)-edoxaban p-toluenesulfonate monohydrate |
Stereospecific commercial solid form |
Claim 6 is the narrowest claim but is also the clearest product claim against Savaysa. It requires all of the following:
- The edoxaban molecular structure.
- The (1S,2R,4S) configuration.
- A p-toluenesulfonate counterion.
- One molecule of water of crystallization, expressed as the monohydrate.
The claim does not merely cover treatment with edoxaban. It covers the chemical composition itself. A generic company that manufactures or imports the same tosylate monohydrate would face a direct product-infringement risk independent of whether the generic product uses the same tablet excipients.
How broad is the patent’s protection across salts, stereoisomers and solid forms?
The claims create a layered protection strategy.
Salt coverage
Claims 1 and 4 cover the named compound with “a salt thereof.” Claims 2, 3, 5 and 6 specifically cover the p-toluenesulfonate salt.
A different edoxaban salt, such as a hydrochloride or mesylate, could fall within claim 1 or claim 4 if it satisfies the claim language and is supported by the patent. It would not literally satisfy the p-toluenesulfonate limitations in claims 2, 3, 5 or 6.
Stereochemical coverage
Claims 4-6 expressly cover the (1S,2R,4S) form. This aligns with the stereochemistry of the marketed edoxaban active ingredient.
Claim 1 and claims 2-3 do not include the stereochemical designation in the text supplied. They may therefore provide broader coverage than claims 4-6, although the enforceable scope would depend on the patent specification, prosecution history and claim construction.
Hydrate coverage
Claims 3 and 6 require the monohydrate. This is important because hydrates and anhydrates can have different crystal lattices, water content, dissolution behavior and manufacturing profiles.
Claim 6 provides the most commercially targeted combination: the active stereoisomer, tosylate salt and monohydrate solid form.
What is the Orange Book status of Savaysa and U.S. Patent 7,365,205?
Savaysa was approved under FDA NDA 206316 on January 8, 2015. FDA labeling identifies edoxaban tosylate as the active ingredient and describes Savaysa tablets in 15 mg, 30 mg and 60 mg strengths.[3]
U.S. Patent 7,365,205 has been associated with Savaysa’s Orange Book-listed product protection. The patent is a composition-of-matter patent rather than a method-of-use patent. That distinction matters because an ANDA applicant challenging the patent would confront protection tied to the drug substance itself.
The relevant approval and patent information is:
| Item |
Data |
| Brand |
Savaysa |
| Active ingredient |
Edoxaban tosylate |
| Dosage form |
Oral tablet |
| Strengths |
15 mg, 30 mg and 60 mg |
| NDA |
206316 |
| Sponsor |
Daiichi Sankyo, Inc. |
| Core patent |
U.S. 7,365,205 |
| Later solid-form patent |
U.S. 8,802,610 |
| Regulatory pathway for generics |
ANDA with Paragraph IV or other certification |
The Orange Book should be treated as the operative source for currently listed patents, pediatric exclusivity and any changes to listed expiration dates. Patent databases may display the original statutory expiration rather than the PTE-adjusted date.
When does U.S. Patent 7,365,205 lose exclusivity?
The original 20-year term is generally calculated from the earliest effective nonprovisional filing date, subject to priority, terminal-disclaimer and patent-term-adjustment rules. For U.S. 7,365,205, the ordinary expiration date is commonly reported as June 22, 2023.
The reported patent-term-extended expiration date is June 22, 2026. The extension reflects FDA regulatory review under 35 U.S.C. § 156. The extension applies to the approved product and is subject to the statutory limits governing patent-term extension.[2]
This produces two dates that should not be conflated:
| Date |
Significance |
| June 22, 2023 |
Original nominal patent expiration |
| June 22, 2026 |
Reported PTE-adjusted expiration |
| After June 22, 2026 |
Core 7,365,205 composition claims generally cease to block ordinary U.S. commercial manufacture, subject to other enforceable patents and regulatory exclusivity |
A generic launch before the extended date would ordinarily require a successful patent challenge, a license or settlement, or a noninfringing product strategy.
What later patents protect edoxaban formulations and crystal forms?
The main related U.S. patent is U.S. Patent No. 8,802,610, which is associated with crystalline forms of edoxaban tosylate monohydrate and related solid-state protection. It has been reported as expiring on August 12, 2027.[4]
This patent is commercially different from U.S. 7,365,205.
| Issue |
U.S. 7,365,205 |
U.S. 8,802,610 |
| Primary protection |
Edoxaban compound, salts and tosylate monohydrate |
Crystalline or solid-state form protection |
| Commercial target |
Active ingredient |
Manufacturing and final API form |
| Claim risk |
Direct composition infringement |
Form and process characterization risk |
| Reported expiration |
June 22, 2026 with PTE |
August 12, 2027 |
| Generic design-around |
Difficult at compound level |
Potentially possible if a nonclaimed form can be made and approved |
A generic applicant may challenge both patents. It may also attempt to use an alternative solid form, amorphous material or different salt. That strategy would require control of polymorphism, stability, dissolution and bioequivalence. Avoiding the later solid-form patent does not by itself avoid U.S. 7,365,205 before its extended expiration.
Are there method-of-use patents for edoxaban?
The claims supplied for U.S. 7,365,205 are composition claims. They do not recite:
- Prevention of stroke in nonvalvular atrial fibrillation.
- Treatment or prevention of venous thromboembolism.
- Treatment after orthopedic surgery.
- A specific dose, renal-function adjustment or patient population.
- A dosing regimen based on body weight or concomitant P-glycoprotein inhibitors.
Edoxaban has multiple clinical uses and dosing restrictions. Those uses can generate separate method-of-use patent activity, but such patents must be analyzed separately from U.S. 7,365,205. A Section viii “skinny-label” strategy could be relevant if unexpired use patents remain listed and the generic omits protected indications. It does not eliminate the composition-of-matter risk from claims 1-6.
Which companies are challenging Savaysa patents?
No widely reported U.S. district-court Paragraph IV litigation against U.S. 7,365,205 or U.S. 8,802,610 should be assumed without checking current FDA Orange Book records, ANDA litigation databases and PACER. A Paragraph IV certification may exist without immediately producing a reported district-court judgment, and an ANDA filing may remain confidential until the patent holder files suit or the FDA publishes relevant information.
The principal potential challengers are generic manufacturers with oral anticoagulant manufacturing capability, including large U.S. and Indian ANDA filers. The relevant legal trigger is not a public statement of intent but an ANDA certification alleging that a listed patent is invalid, unenforceable or not infringed.
How strong is the patent estate for edoxaban?
The estate is strong against a conventional generic that seeks to sell the same active ingredient as edoxaban tosylate monohydrate before 2026.
Strengths
- The core patent claims the chemical entity and salts.
- Claims 2, 3, 5 and 6 target the commercially relevant tosylate form.
- Claim 6 directly targets the stereospecific monohydrate used in Savaysa.
- A generic cannot avoid compound claims by changing tablet excipients.
- The later solid-form patent may extend formulation and manufacturing risk beyond the core patent’s PTE date.
Limitations
- The core patent is close to or beyond its ordinary term.
- Claims 3 and 6 are narrow and may depend on proof of the claimed hydration and crystalline state.
- A different salt or solid form may create a design-around path if it remains clinically and regulatorily viable.
- Method-of-use protection is separate and must be evaluated claim by claim.
- Patent validity may be challenged based on anticipation, obviousness, written description, enablement, double patenting or prosecution-history issues.
The most vulnerable part of the estate from a design-around perspective is the solid-form layer. The least flexible part for a generic is the active compound itself, because changing the compound would no longer produce edoxaban.
What generic launch scenarios exist for Savaysa?
Launch after June 22, 2026
This is the clearest pathway if no blocking patent remains enforceable and FDA approval is obtained. The later U.S. 8,802,610 patent could delay a generic using the patented crystalline form until its reported August 12, 2027 expiration.
Paragraph IV launch before June 22, 2026
A generic applicant could certify that U.S. 7,365,205 is invalid, unenforceable or not infringed. Daiichi Sankyo could then sue within the statutory period, potentially triggering a 30-month stay of FDA approval under the Hatch-Waxman framework.[5]
Alternative-salt or alternative-form launch
A company could develop a different edoxaban salt or solid form. This would face three barriers:
- It must avoid the broad salt language in claims 1 or 4.
- It must avoid any later form or process claims.
- It must demonstrate pharmaceutical equivalence, bioequivalence, stability and acceptable manufacturing control.
Skinny-label launch
A skinny-label strategy could remove patented indications from the proposed label. It would not address direct infringement allegations based on manufacturing, importing or selling edoxaban tosylate monohydrate under claims 1-6.
What litigation and settlement issues affect edoxaban?
A settlement involving an ANDA filer could establish an agreed launch date before patent expiration, subject to antitrust and regulatory scrutiny. The commercial outcome would depend on:
- Whether the settlement permits an authorized generic.
- Whether the launch date is tied to the 2026 or 2027 patent date.
- Whether the generic may use the same tosylate monohydrate.
- Whether the agreement includes a covenant not to sue.
- Whether patent challenges are withdrawn or preserved for other filers.
No settlement terms should be inferred solely from the absence of a publicly reported merits decision. The relevant records are Orange Book updates, FDA patent certifications, district-court complaints and docketed settlement papers.
How does edoxaban’s patent estate compare with competing oral anticoagulants?
| Drug |
Mechanism |
Core commercial protection profile |
Generic risk pattern |
| Edoxaban |
Direct factor Xa inhibitor |
Compound plus tosylate monohydrate and later solid-form protection |
Product patent and solid-form challenge |
| Apixaban |
Direct factor Xa inhibitor |
Compound, formulation and method-of-use patents |
Multiple Orange Book patents and settlement-driven entry |
| Rivaroxaban |
Direct factor Xa inhibitor |
Compound, formulation and use patents |
Earlier and broader generic litigation history |
| Dabigatran etexilate |
Direct thrombin inhibitor |
Compound and formulation protection |
Salt, formulation and use issues |
Edoxaban’s estate is narrower in claim count than some competing anticoagulant estates but has a high-value composition patent. Its principal commercial question is timing: whether generic entry can occur after the 2026 core patent date but before the 2027 solid-form date.
What is the geographic scope of U.S. Patent 7,365,205?
The patent has territorial effect only in the United States. It does not prevent manufacture, sale or use outside the United States unless corresponding foreign patents exist.
Daiichi Sankyo pursued corresponding patent protection in multiple jurisdictions. Foreign expiry dates, supplementary protection certificates and litigation outcomes vary by country. A company planning global edoxaban entry must review:
- European Patent Office and national validations.
- Japan Patent Office records.
- Canadian and Australian patent registers.
- Country-specific pediatric extensions and supplementary protection certificates.
- Local formulation and process patents.
A U.S. freedom-to-operate conclusion cannot be exported to Europe, Japan or other markets.
What manufacturing and intellectual-property barriers remain?
The API must be manufactured with the claimed stereochemistry and, for the commercial product, the required tosylate monohydrate characteristics. The main technical barriers are:
- Stereochemical control of the cyclohexyl core.
- Reproducible formation of the tosylate salt.
- Control of water content.
- Control of polymorphism and crystallinity.
- Batch-to-batch dissolution and particle-size consistency.
- Stability under tablet manufacturing and storage conditions.
These barriers matter even after the core patent expires. A generic may be legally free to make edoxaban but unable to reproduce the reference product’s solid-state performance without infringing a later form patent or developing a validated alternative.
Key Takeaways
- U.S. Patent 7,365,205 is an edoxaban composition patent assigned to Daiichi Sankyo.
- Claims 1 and 4 cover the named edoxaban compound and salts.
- Claims 2 and 5 specifically cover edoxaban p-toluenesulfonate.
- Claims 3 and 6 cover the p-toluenesulfonate monohydrate.
- Claim 6 is the most commercially targeted claim because it recites the stereospecific commercial API form.
- The patent’s ordinary expiration was June 22, 2023.
- The reported patent-term-extended expiration is June 22, 2026.
- U.S. Patent 8,802,610 may create additional solid-form exposure through its reported August 12, 2027 expiration.
- A generic using edoxaban tosylate monohydrate faces direct product-patent risk before the relevant expiration dates.
- An alternative salt or solid form may offer a design-around route, but it must satisfy FDA bioequivalence, stability and manufacturing requirements.
- Edoxaban is a small molecule, so biosimilar approval is not applicable. The relevant pathway is an ANDA, not a biosimilar application.
FAQs About U.S. Patent 7,365,205 and Edoxaban
Does U.S. Patent 7,365,205 claim Savaysa tablets?
It claims the edoxaban active ingredient and specified salt and hydrate forms, not the complete tablet formulation with all inactive ingredients. A tablet containing the claimed edoxaban tosylate monohydrate can implicate the patent.
Can a generic avoid claim 6 by changing the tablet excipients?
No. Changing excipients does not avoid a claim directed to the API composition. The generic would need to use a nonclaimed active form or challenge the patent.
Is edoxaban eligible for a biosimilar application?
No. Edoxaban is a chemically synthesized small molecule. A competing product would generally use the ANDA pathway if it seeks approval as a generic version of Savaysa.
Does expiration of U.S. 7,365,205 automatically permit generic launch?
No. FDA approval requirements, any later unexpired Orange Book patents, litigation stays, exclusivity periods and manufacturing constraints can still affect launch timing.
Does a different edoxaban salt necessarily avoid all claims?
No. Claims 1 and 4 recite the compound “a salt thereof.” A different salt may avoid the claims limited specifically to p-toluenesulfonate, but it may still fall within the broader salt claims.
References
- United States Patent and Trademark Office. (2008). U.S. Patent No. 7,365,205: Novel cyclohexane derivatives.
- United States Patent and Trademark Office. (n.d.). Patent term adjustment and patent term extension records for U.S. Patent No. 7,365,205.
- U.S. Food and Drug Administration. (2015). Savaysa (edoxaban) prescribing information. Daiichi Sankyo, Inc.
- United States Patent and Trademark Office. (2014). U.S. Patent No. 8,802,610: Crystalline forms of edoxaban tosylate.
- U.S. Food and Drug Administration. (2023). Approved drug products with therapeutic equivalence evaluations. 42nd ed.
