US Patent 9,149,532: Edoxaban Tablet Formulation Scope, Patent Strength, and Generic Entry Risk
US Patent 9,149,532 protects a specific solid oral tablet formulation of edoxaban, including defined excipient ratios, coating levels, salt forms, drug loading, and dissolution performance. The patent does not broadly claim edoxaban as a molecule or every edoxaban dosage form. Its enforceable scope is concentrated on tablets that contain the claimed active ingredient together with a qualifying sugar alcohol, water-swelling additive, and coating system.
The patent was issued on September 29, 2015, to Daiichi Sankyo Co., Ltd. It is directed to edoxaban tablets marketed in the United States as Savaysa and outside the United States as Lixiana. The principal commercial risk is formulation-specific infringement by an ANDA applicant, not direct blocking of every edoxaban generic.
What drug does US Patent 9,149,532 protect?
The active ingredient claimed by US 9,149,532 is edoxaban, including certain pharmaceutically acceptable salts and hydrates.
Edoxaban is a direct factor Xa inhibitor. The commercial product is edoxaban tosylate monohydrate, generally described in the claims as the p-toluenesulfonate monohydrate. Savaysa tablets are approved for prevention of stroke and systemic embolism in patients with nonvalvular atrial fibrillation and for treatment and reduction in the risk of recurrence of deep-vein thrombosis and pulmonary embolism.[1]
The patent claims a formulation, not the pharmacological use of edoxaban itself. A product containing edoxaban can fall outside the patent if it does not satisfy every limitation of at least one asserted claim.
Core active ingredient
The chemical name in the claims corresponds to edoxaban. Claim 6 specifically identifies the hydrochloride salt, while claim 7 identifies edoxaban p-toluenesulfonate monohydrate.
The distinction matters because the claimed composition must contain:
- Edoxaban free compound;
- A pharmaceutically acceptable salt; or
- A hydrate of the compound or salt.
Claim 7 is commercially significant because edoxaban tosylate monohydrate is the salt form used in Savaysa.
What does claim 1 of US 9,149,532 require?
Claim 1 is the broadest independent claim and requires a tablet containing all of the following:
| Claim element |
Required limitation |
| Dosage form |
Tablet |
| Active ingredient |
Edoxaban, an acceptable salt, or a hydrate |
| Sugar alcohol |
Mannitol, xylitol, erythritol, or a combination |
| Sugar-alcohol concentration |
40 to 60 wt.% of the total composition |
| Water-swelling additive |
Pregelatinized starch, crystalline cellulose, or both |
| Excipient ratio |
Sugar alcohol to water-swelling additive of 1.5:1 to 4:1 by weight |
| Coating |
Hypromellose, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, polyvinyl alcohol, or a combination |
| Coating concentration |
1.5 to 5 wt.% of total composition |
A generic tablet must satisfy each limitation to infringe claim 1 literally. Omitting one listed excipient category, moving the sugar alcohol outside the concentration range, or using a sugar alcohol not named in the Markush group may create a non-infringement position, subject to equivalents analysis.
How narrow is the formulation claim?
The claim is narrower than a conventional product-by-process or broad excipient claim because it imposes multiple quantitative limitations.
Required sugar alcohol
The sugar alcohol must be one or more of:
- Mannitol;
- Xylitol;
- Erythritol.
Sorbitol, maltitol, lactitol and other polyols are not expressly covered by claim 1. A formulation using sorbitol as the only sugar alcohol would not literally satisfy the sugar-alcohol limitation.
Claim 2 narrows the formulation to mannitol. It does not broaden claim 1.
Required water-swelling additive
The tablet must contain pregelatinized starch, crystalline cellulose, or both. The claim does not cover every conventional disintegrant. Crospovidone, sodium starch glycolate, low-substituted hydroxypropyl cellulose and croscarmellose sodium are not expressly included unless used together with one of the claimed additives and the remaining limitations are met.
Claim 3 limits the water-swelling additive to pregelatinized starch.
Quantitative ratio
The sugar alcohol-to-water-swelling-additive ratio must be between 1.5:1 and 4:1 by weight.
For example:
| Sugar alcohol |
Water-swelling additive |
Ratio |
Claim 1 result |
| 50 parts |
20 parts |
2.5:1 |
Within range |
| 40 parts |
10 parts |
4:1 |
Within range |
| 45 parts |
10 parts |
4.5:1 |
Outside range |
| 30 parts |
20 parts |
1.5:1 |
Within range |
The calculation should be based on the actual quantitative amounts in the tablet composition, not merely the composition of a premix or granulation, unless the patent’s specification and prosecution history support a different interpretation.
Coating limitation
The tablet must be coated with at least one of the specified cellulose-based or polymeric coating agents, and the coating agent must account for 1.5 to 5 wt.% of the total composition.
Claim 5 narrows the coating to hypromellose. Claim 4 covers hypromellose, ethyl cellulose and polyvinyl alcohol.
A film-coated tablet with the same internal core but a coating level below 1.5 wt.% or above 5 wt.% may avoid literal infringement of claim 1. The relevant issue is whether the percentage refers to the coating agent itself or the total coating system, including pigments, plasticizers and other coating excipients. The intrinsic record and prosecution history would control that construction.
What do claims 2 through 13 add?
Salt and hydrate claims
Claims 6 and 7 identify specific edoxaban forms:
- Claim 6: edoxaban hydrochloride.
- Claim 7: edoxaban p-toluenesulfonate monohydrate.
Claim 7 is particularly relevant to the marketed product. A formulation using edoxaban tosylate monohydrate and otherwise meeting claim 1 faces the strongest literal infringement exposure.
Drug-loading claims
Claim 8 requires edoxaban, its salt or hydrate to be present at 12 to 25 wt.% of the total composition.
Claim 11 separately requires 15 to 60 wt.%. Because both claims depend directly on claim 1, they create overlapping but distinct ranges:
- Claim 8: 12 to 25 wt.%.
- Claim 11: 15 to 60 wt.%.
- Overlap: 15 to 25 wt.%.
A tablet with 30 wt.% edoxaban may fall within claim 11 but outside claim 8. A tablet with 13 wt.% may fall within claim 8 but outside claim 11.
The apparent overlap is legally permissible because dependent claims can define alternative narrower embodiments of the independent claim.
Water-swelling additive concentration
Claim 9 requires the water-swelling additive to represent 10 to 30 wt.% of the composition. This limitation applies in addition to the 1.5:1 to 4:1 ratio in claim 1.
Coating concentration
Claim 10 narrows the coating-agent concentration to 2 to 5 wt.%, eliminating the 1.5 to below 2 wt.% portion of claim 1.
Dissolution claims
Claims 12 and 13 impose dissolution-performance limitations using:
- A pH 6.8 dissolution medium;
- Paddle apparatus;
- 50 rpm rotation;
- Average percent dissolution;
- Measurements at 30 and 60 minutes.
Claim 12 requires at least:
- 60% dissolution at 30 minutes; and
- 70% dissolution at 60 minutes.
Claim 13 requires at least:
- 70% dissolution at 30 minutes; and
- 80% dissolution at 60 minutes.
Claim 13 is narrower than claim 12 because its thresholds are higher. These claims create testing and reproducibility issues. An accused generic may dispute infringement based on medium preparation, apparatus qualification, sampling, assay methodology, tablet age, storage conditions, or statistical treatment of “average” dissolution.
What patents protect Savaysa and edoxaban?
The US edoxaban estate has several distinct patent categories:
| Patent category |
Subject matter |
Relevance to generic entry |
| Compound patents |
Edoxaban molecule and related anticoagulant compounds |
Can block use of the active ingredient during the patent term |
| Salt and solid-state patents |
Edoxaban salts, hydrates and crystalline forms |
Can block use of the commercial tosylate monohydrate or another protected solid form |
| Formulation patents |
Tablets, excipient systems, coating and dissolution characteristics |
Directly relevant to US 9,149,532 |
| Method-of-use patents |
Stroke prevention, DVT and pulmonary embolism treatment |
Relevant to labeling and induced-infringement analysis |
| Manufacturing patents |
Preparation of edoxaban, intermediates and drug substance |
Can raise supply-chain and API-production risk |
| Regulatory exclusivity |
New chemical entity and approval-related exclusivities |
Separate from patent expiration |
US 9,149,532 is best characterized as a formulation patent. It is not a complete substitute for compound, salt, method-of-use or manufacturing patents.
When does US Patent 9,149,532 lose exclusivity?
The patent issued in 2015 and has a nominal 20-year term measured from the applicable nonprovisional filing date, subject to patent-term adjustment, terminal disclaimers and any applicable regulatory patent-term extension.[2]
The relevant term is expected to run into approximately October 2031 based on the patent family’s 2011 filing history. The precise expiration date must be taken from the USPTO Patent Examination Data System and Patent Center term records. A patent-term adjustment could move the expiration date later, while a terminal disclaimer could shorten it.
The patent’s expiration is separate from FDA exclusivity:
| Exclusivity type |
General relevance |
| New chemical entity exclusivity |
Blocks ANDA approval for five years from approval, subject to statutory exceptions |
| Three-year exclusivity |
Applies to certain new clinical investigations and does not independently block all ANDAs |
| Orphan exclusivity |
Not generally associated with Savaysa’s principal approvals |
| Patent exclusivity |
Depends on each patent’s enforceable term and scope |
FDA approved Savaysa in January 2015. The five-year NCE period therefore expired in January 2020, leaving patent rights as the principal continuing barrier to approval and launch.[1,3]
What is the Orange Book status of US 9,149,532?
US 9,149,532 is associated with the Savaysa edoxaban product and is relevant to Orange Book-listed patent analysis. Orange Book listing status can change through delisting, product changes, patent-term events and FDA administrative updates.[3]
For an ANDA applicant, the key questions are:
- Is the patent listed against the relevant Savaysa strength and dosage form?
- Does the applicant submit a Paragraph IV certification?
- Does the NDA holder sue within 45 days?
- Does the litigation trigger a 30-month stay?
- Is the patent expired, disclaimed, delisted or subject to a statutory non-infringement certification?
The patent’s formulation limitations make a Paragraph IV strategy technically viable. An applicant may formulate a tablet outside the claimed excipient ranges or use a different disintegrant and coating system. That approach carries less formulation freedom than a simple non-infringement certification because the ANDA product must still satisfy dissolution and bioequivalence requirements.
What Paragraph IV challenges and litigation affect this patent?
A Paragraph IV certification against US 9,149,532 would require the ANDA applicant to assert that the patent is invalid, unenforceable or will not be infringed. The most likely technical defenses would involve:
- Sugar alcohol concentration outside 40 to 60 wt.%.
- Use of a non-listed sugar alcohol.
- Sugar alcohol-to-water-swelling-additive ratio outside 1.5:1 to 4:1.
- Coating-agent concentration outside 1.5 to 5 wt.%.
- Use of an unlisted coating polymer.
- Use of an edoxaban form outside the relevant claim.
- Failure to meet the dissolution limitations in claims 12 or 13.
- Lack of written description or enablement for particular combinations.
- Obviousness based on tablet formulation references and edoxaban prior art.
The supplied record does not establish a final adjudication, settlement agreement or launch license specific to US 9,149,532. No conclusion about a particular generic company’s Paragraph IV status should be drawn solely from the patent claims.
How strong is the patent estate for generic entry?
US 9,149,532 is moderately strong as a formulation patent and weaker as a standalone barrier to all edoxaban competition.
Strengths
- Claim 1 combines composition, ratio, loading and coating limitations.
- Claim 7 maps directly to the commercial edoxaban tosylate monohydrate form.
- Claims 12 and 13 add measurable dissolution performance.
- The formulation has multiple dependent-claim fallback positions.
- A generic cannot avoid the patent merely by changing one minor excipient if the remaining composition still falls within claim 1.
Weaknesses
- The claim does not cover every edoxaban tablet.
- The sugar alcohol Markush group is limited.
- The water-swelling additive category is defined narrowly.
- Quantitative ranges create design-around opportunities.
- Dissolution claims can be vulnerable to testing variability and enablement or obviousness challenges.
- The patent does not independently prevent use of edoxaban in a non-tablet dosage form or a materially different tablet composition.
The principal design-around path is to alter the excipient architecture while preserving bioequivalence. Examples include using a non-listed polyol, changing the sugar alcohol ratio, selecting a different swelling or disintegrating agent, or adjusting coating weight outside the claimed range.
How does US 9,149,532 compare with compound and method-of-use patents?
| Issue |
US 9,149,532 |
Compound patent |
Method-of-use patent |
| Protected subject matter |
Tablet formulation |
Edoxaban molecule or chemical class |
Approved therapeutic use |
| Primary infringement evidence |
Composition records and formulation testing |
API identity and chemical structure |
Label, prescribing information and intended use |
| Design-around potential |
Relatively high |
Low if compound remains protected |
Moderate, depending on label |
| Relevance to ANDA |
Product-by-product formulation analysis |
Broad product barrier |
Labeling and inducement analysis |
| Key litigation issue |
Claim construction and quantitative testing |
Validity and patent term |
Skinny-label scope and induced infringement |
A generic company can avoid this formulation patent while still encountering separate compound, salt, method-of-use or manufacturing patents. The commercial launch assessment must therefore evaluate the entire edoxaban estate rather than US 9,149,532 in isolation.
What generic launch scenarios exist?
Scenario 1: Infringing formulation
The ANDA product uses edoxaban tosylate monohydrate, mannitol at 40 to 60 wt.%, pregelatinized starch or crystalline cellulose at the required ratio, and a 1.5 to 5 wt.% hypromellose coating. This scenario creates substantial literal infringement risk.
Scenario 2: Non-infringing formulation
The applicant uses a different polyol, a non-listed swelling agent, a ratio outside the claimed range, or a coating outside the claimed concentration. The applicant must still meet FDA dissolution, stability and bioequivalence requirements.
Scenario 3: Paragraph IV challenge
The applicant argues that the claims are invalid or not infringed. The commercial result depends on litigation timing, the 30-month stay, preliminary relief and the remaining life of other edoxaban patents.
Scenario 4: At-risk launch
The applicant launches before final resolution after receiving a favorable district-court decision or accepting litigation risk. Exposure would include damages, an injunction and potential disruption of distribution.
What geographic coverage does the patent have?
US 9,149,532 provides rights only in the United States. Corresponding foreign family members may exist in Europe, Japan, China, Canada and other jurisdictions, but each family member has independent prosecution history, claim scope, validity and expiration.
A US non-infringement position does not establish freedom to operate in Europe or Japan. Conversely, an adverse foreign prosecution outcome does not automatically invalidate the US patent.
Key Takeaways
- US 9,149,532 is a formulation patent for edoxaban tablets, not a broad edoxaban compound patent.
- Claim 1 requires a tablet, a listed sugar alcohol at 40 to 60 wt.%, a listed water-swelling additive, a 1.5:1 to 4:1 ratio and a specified coating at 1.5 to 5 wt.%.
- Claim 7 is commercially important because it covers edoxaban p-toluenesulfonate monohydrate.
- Claims 12 and 13 impose dissolution-performance requirements that may complicate infringement testing.
- The patent is expected to remain relevant into approximately 2031, subject to the official USPTO term calculation.
- The patent offers meaningful protection against copycat Savaysa formulations but leaves several formulation design-around routes.
- Generic entry must be assessed against the full edoxaban estate, including compound, salt, method-of-use and manufacturing patents.
FAQs
Does US 9,149,532 cover all edoxaban tablets?
No. It covers tablets meeting all limitations of at least one claim. Tablets using different excipients, ratios, coating levels or dosage-form technologies may fall outside its literal scope.
Does using edoxaban hydrochloride avoid the patent?
No. Claim 6 expressly identifies edoxaban hydrochloride. A hydrochloride tablet can infringe if it also satisfies the formulation, ratio and coating limitations.
Can a generic use mannitol and avoid infringement?
Yes, potentially. Mannitol alone does not establish infringement. The tablet must also meet the quantitative mannitol range, water-swelling additive requirement, excipient ratio, coating limitation and all other applicable claim elements.
Are dissolution claims 12 and 13 independent formulation claims?
No. They depend on claim 1 and therefore incorporate every limitation of claim 1. They add dissolution thresholds rather than replacing the underlying composition requirements.
Does patent expiration eliminate FDA approval barriers for edoxaban generics?
No. Expiration of this formulation patent would remove one barrier. Other listed patents, unlisted patent disputes, regulatory requirements, exclusivity issues and manufacturing constraints may still affect approval or launch.
References
- U.S. Food and Drug Administration. (2015). Savaysa (edoxaban tosylate) prescribing information.
- United States Patent and Trademark Office. (2015). U.S. Patent No. 9,149,532, Pharmaceutical composition.
- U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
