United States Patent 9,457,036: Tenofovir Disoproxil Fumarate–Emtricitabine Tablet Claims and Patent Landscape

United States Patent 9,457,036 is directed to fixed-dose tablet formulations containing 300 mg tenofovir disoproxil fumarate (TDF) and 200 mg emtricitabine (FTC), the active combination marketed in Truvada and generic products. Its principal protection is formulation-specific rather than molecule-specific. The broadest claims require a defined excipient architecture, tablet dosage form, and stability performance of no more than 5% degradation after six months at 40°C/75% relative humidity with silica-gel desiccant.

The patent does not, based on the supplied claims, cover TDF or FTC as chemical entities, all TDF/FTC combinations, or every tablet containing the two active ingredients. Commercial risk depends on whether a competing product uses the claimed excipient categories and satisfies the stability limitations.

What does U.S. Patent 9,457,036 protect?

The patent protects a fixed-dose combination tablet containing:

Required feature	Claim requirement
Tenofovir component	300 mg tenofovir disoproxil fumarate
Emtricitabine component	200 mg emtricitabine
Dosage form	Tablet
Binder	One or more listed binders
Disintegrant	One or more listed disintegrants
Lubricant	One or more listed lubricants
Stability	No more than 5% degradation of TDF or FTC after six months
Storage condition	40°C/75% relative humidity
Packaging condition	Packaged with silica-gel desiccant

The key limitation is the combination of composition and performance. A product must satisfy both the ingredient limitations and the specified stability test to fall within claim 1 or claim 16.

The claims use “comprising,” which generally makes them open-ended. A product may contain additional excipients and remain within the claim if it includes all required elements. Additional ingredients therefore do not automatically avoid infringement.

How broad are the independent claims?

Claim 1

Claim 1 is the primary broad formulation claim. It covers a tablet containing the specified TDF and FTC strengths, a listed binder, a listed disintegrant, and a listed lubricant.

The binder list includes:

Povidone
Gelatin
Hydroxypropyl methylcellulose
Cellulose
Microcrystalline cellulose
Starch
Acacia

The disintegrant list includes:

Sodium starch glycolate
Crosslinked povidone
Cross-linked sodium carboxymethylcellulose, commonly croscarmellose sodium
Alginic acid

The lubricant list includes:

Magnesium stearate
Stearic acid
Talc

Claim 1 does not require a particular manufacturing process, tablet weight, dissolution profile, compression force, particle size, or coating. It also does not require a particular amount of each excipient.

The principal limitation is the stability requirement. A formulation with the listed ingredients may avoid claim 1 if it fails the six-month degradation threshold. Conversely, a formulation with additional excipients may remain covered if it meets all listed requirements.

Claim 16

Claim 16 is a second independent formulation claim. It is similar to claim 1 but changes the excipient lists.

The binder list adds pregelatinized starch and expressly includes it in place of the broader “starch” category. The disintegrant list adds maize starch. The claim again requires a tablet, the 300 mg/200 mg active combination, silica-gel packaging, and no more than 5% degradation after six months under accelerated conditions.

Claim 16 may have been drafted to preserve coverage over specific formulation embodiments and to reduce potential arguments that pregelatinized starch or maize starch falls outside the scope of claim 1.

Which dependent claims cover specific formulations?

Claims 5 through 11 narrow the patent to specific excipient combinations. Because these claims depend on broader claims and use “comprising,” the listed amounts establish minimum required components unless the claim language is interpreted otherwise.

Claim	Formulation characteristics
5	Pregelatinized starch, croscarmellose sodium, lactose monohydrate, microcrystalline cellulose, magnesium stearate
6	50 mg pregelatinized starch, 60 mg croscarmellose sodium, 80 mg lactose monohydrate, 300 mg microcrystalline cellulose, 10 mg magnesium stearate
7	50 mg pregelatinized starch, 60 mg croscarmellose sodium, lactose monohydrate, 200 mg microcrystalline cellulose, 10 mg magnesium stearate
8	Claim 1 formulation plus colloidal silicon dioxide
9	50 mg pregelatinized starch, 60 mg croscarmellose sodium, 175 mg lactose monohydrate, 200 mg microcrystalline cellulose, 10 mg magnesium stearate, 5 mg colloidal silicon dioxide
10	Hydroxypropyl methylcellulose, lactose, pregelatinized starch, magnesium stearate
11	112 mg hydroxypropyl methylcellulose and 7 mg magnesium stearate, with lactose and pregelatinized starch

Claims 6 and 9 each describe an approximately 1,000 mg tablet:

Claim 6: 300 mg TDF + 200 mg FTC + 50 mg starch + 60 mg croscarmellose + 80 mg lactose + 300 mg microcrystalline cellulose + 10 mg magnesium stearate = 1,000 mg.
Claim 9: 300 mg TDF + 200 mg FTC + 50 mg starch + 60 mg croscarmellose + 175 mg lactose + 200 mg microcrystalline cellulose + 10 mg magnesium stearate + 5 mg colloidal silicon dioxide = 1,000 mg.

The precise quantitative embodiments can be commercially important because they may correspond to a development batch, manufacturing process, or marketed generic composition.

What stability performance does the patent require?

Claim 1 and claim 16 require no more than 5% degradation of TDF or FTC after six months when packaged with silica-gel desiccant and stored at 40°C/75% relative humidity.

This limitation raises several claim-construction and infringement issues:

The test uses accelerated stability conditions rather than ordinary labeled storage.
The claim specifies silica-gel desiccant, so packaging configuration may affect the result.
The phrase “degradation of the tenofovir disoproxil fumarate or emtricitabine” may require analysis of active-ingredient loss, degradation products, or both.
The claim does not identify a particular analytical method, impurity threshold, batch number, or sampling interval.
A challenger may dispute whether the stability limitation is sufficiently definite or reproducible if the patent specification does not identify the analytical protocol with adequate precision.

Claim 12 separately requires less than 1% impurities related to TDF and FTC. That is narrower than the 5% degradation limitation and appears directed to chemical purity rather than only active-ingredient assay loss.

How do claims 2 through 4 affect infringement risk?

Claims 2, 3, and 4 require less than 1%, less than 0.1%, and less than 0.01% TDF degradation over a 24-hour period.

These claims are unusually narrow and potentially vulnerable on technical grounds. The claims do not state the temperature, humidity, packaging, analytical method, sampling method, or definition of degradation for the 24-hour test. A product may satisfy the six-month claim 1 stability requirement but fail to meet one of these short-duration degradation limits, or vice versa.

The claims create a layered protection structure:

Claim group	Protection level
Claims 1 and 16	Broad formulation and six-month stability coverage
Claims 2-4	Narrow short-term TDF degradation limits
Claims 5-11	Specific excipient and quantitative formulations
Claim 12	Less than 1% related impurities
Claims 13-14	HIV-treatment method claims
Claim 15	Pregelatinized-starch limitation

Claims 2 through 4 may provide limited incremental commercial value unless the patent owner can establish a consistent, validated testing protocol.

Do the method-of-use claims cover HIV treatment?

Claims 13 and 14 cover treating symptoms or effects of HIV infection in an infected animal by administering the claimed pharmaceutical dosage form.

The method claims depend on the formulation claims. They do not independently cover administration of any TDF/FTC product. The administered product must satisfy the underlying formulation limitations.

The reference to an “animal” is broad drafting language that can encompass humans, but claim scope would depend on the specification, prosecution history, and applicable claim-construction principles. The claims are treatment claims, not prevention claims. They do not expressly cover pre-exposure prophylaxis or post-exposure prophylaxis.

The commercial importance of these claims is limited where an approved product label contains HIV treatment and the formulation claims are difficult to prove. In a Hatch-Waxman dispute, a method claim may still create a Paragraph IV issue if listed in the FDA Orange Book and tied to an approved indication. Orange Book listing depends on FDA listing practices and the patent holder’s submission, not merely on the existence of a granted patent. [1]

How does Patent 9,457,036 compare with the core TDF and FTC patent estate?

The patent occupies a different layer from the foundational patents covering the active pharmaceutical ingredients.

Patent layer	Typical protected subject matter	Relevance to Patent 9,457,036
Compound patents	TDF, FTC, salts, prodrugs, or related chemical entities	Separate from the formulation claims
Combination patents	TDF and FTC used together	Potentially overlapping product coverage
Formulation patents	Tablet composition, excipients, stability, manufacturing	Directly relevant
Method patents	HIV treatment or prophylaxis	Claims 13 and 14
Manufacturing patents	Granulation, compression, coating, impurity control	May create additional barriers
Regulatory exclusivity	New drug, pediatric, or other FDA exclusivity	Separate from patent rights

Truvada was approved by FDA in 2004 as a fixed-dose combination of FTC and TDF. Its prescribing information identifies the active strengths as 200 mg FTC and 300 mg TDF. [2] The foundational Gilead patent estate historically included patents directed to TDF and combination use, but those rights are legally distinct from a third-party or generic formulation patent such as Patent 9,457,036.

A company can therefore face different risks at different times:

A compound patent may block sale of the active ingredient.
A combination patent may block the TDF/FTC product.
Patent 9,457,036 may block a particular tablet formulation.
A manufacturing patent may block the process used to produce the tablet.
Orange Book-listed method patents may affect ANDA certification and launch timing.

When does Patent 9,457,036 lose exclusivity?

The exact expiration date cannot be calculated from the supplied claims alone. U.S. patent term generally runs 20 years from the earliest effective nonprovisional U.S. filing date, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and other statutory adjustments. [3]

A reliable expiration analysis requires the patent’s:

Earliest effective priority date
U.S. nonprovisional filing date
Patent-term adjustment
Patent-term extension, if any
Terminal disclaimer, if any
Reexamination or post-grant changes

The grant date, September 27, 2016, does not itself establish expiration. If the patent claims priority to an application filed around 2009 or 2010, ordinary term would generally place expiration around 2029 or 2030, before any adjustment. That estimate is not a legal expiration determination.

Is Patent 9,457,036 likely listed in the Orange Book?

An issued patent is not automatically an Orange Book patent. FDA regulations require patents submitted by the NDA holder to meet listing criteria, and product-specific listing is tied to the approved drug and the patent’s claimed subject matter. [1]

For Patent 9,457,036, the listing analysis would focus on:

Whether the patent owner or an NDA holder submitted it to FDA.
Whether the claims cover the approved TDF/FTC product.
Whether the claims cover the product’s formulation, composition, or approved method of use.
Whether the patent was timely submitted.
Whether FDA accepted or removed the listing.

The claim text alone does not establish Orange Book listing. If the patent is not listed against the relevant NDA, an ANDA applicant generally would not have to provide a Paragraph IV certification specifically for this patent, although the patent could still support a conventional infringement action.

What Paragraph IV risks exist for generic TDF/FTC products?

A generic manufacturer faces a Paragraph IV risk if it certifies that a listed patent is invalid, unenforceable, or will not be infringed. The NDA holder or patent owner may then bring suit within the statutory period, potentially triggering a 30-month stay of ANDA approval under the Hatch-Waxman framework. [4]

For this patent, a generic formulation developer would likely evaluate:

Whether the product uses one of the listed binders.
Whether it uses one of the listed disintegrants.
Whether it uses one of the listed lubricants.
Whether it is a tablet containing exactly 300 mg TDF and 200 mg FTC.
Whether it meets the six-month accelerated stability limitation.
Whether its impurities remain below the claim 12 threshold.
Whether the patent is listed in the Orange Book.
Whether a formulation redesign can avoid literal infringement.

A formulation using a non-listed binder, non-listed disintegrant, or non-listed lubricant may have a credible non-infringement position. The doctrine of equivalents may still be asserted, but prosecution history and the detailed Markush categories would constrain that argument.

What generic launch scenarios are most plausible?

Scenario 1: Formulation outside the Markush lists

A generic manufacturer uses a different binder, disintegrant, or lubricant and documents that the product does not contain a claimed category. This is the cleanest design-around path.

Scenario 2: Same excipients but failure of the stability limitation

A product may contain the listed ingredients but fail the claimed accelerated stability requirement. This scenario requires reliable testing because the patent owner may challenge the test method or product sampling.

Scenario 3: Paragraph IV litigation

If listed, a generic applicant may file a Paragraph IV certification. Litigation would likely focus on claim construction, written description, enablement, anticipation, obviousness, and whether the accused product meets the stability limitation.

Scenario 4: Post-expiration entry

A generic applicant may file a Paragraph III certification and wait for patent expiration. This avoids an infringement dispute but delays commercial launch until the certified expiration date.

What are the main validity vulnerabilities?

The principal validity challenges are likely to involve:

Obviousness over known TDF/FTC fixed-dose tablets.
Anticipation by prior-art formulations containing the same active strengths and conventional excipients.
Lack of written description for broad excipient Markush groups.
Enablement of the claimed stability result across all listed excipients.
Indefiniteness of the degradation-testing language.
Lack of clear analytical standards for the 24-hour degradation claims.
Obviousness of adding colloidal silicon dioxide or adjusting filler quantities.
Patentable distinction between routine formulation optimization and an unexpected stability result.

The patent’s strongest claims are likely the specific quantitative formulations in claims 6 and 9 if the specification provides comparative data showing an unexpected stability benefit. Its broadest claims face greater exposure because they cover many conventional pharmaceutical excipients without requiring a specific quantity or process.

What litigation, licensing, and settlement issues affect the patent?

The supplied claim text does not establish any litigation, license, covenant not to sue, or settlement agreement involving Patent 9,457,036. Those issues must be separated from the patent’s technical scope.

For transaction diligence, the relevant checks are:

Diligence issue	Commercial significance
Patent ownership and assignments	Determines enforcement authority
Orange Book status	Determines ANDA certification exposure
ANDA litigation	May delay approval or launch
License agreements	May permit generic or regional commercialization
Settlement terms	May establish an agreed launch date
Terminal disclaimer	May tie expiration to another patent
Continuation applications	May preserve later-dated formulation claims
Foreign family patents	May affect non-U.S. launch strategy

No biosimilar risk applies to TDF/FTC. TDF and FTC are small-molecule active ingredients regulated through the generic-drug pathway, not biologics regulated through the biosimilar pathway. The relevant competitors are ANDA applicants and finished-dose generic manufacturers.

How strong is the patent estate for commercial purposes?

Patent 9,457,036 has moderate formulation-specific value and limited standalone franchise value.

Its strengths are:

Exact alignment with the commercial 300 mg/200 mg TDF/FTC dose.
Coverage of common excipients used in direct-compression and granulated tablets.
A stability limitation tied to a recognized accelerated condition.
Narrow quantitative claims that may correspond to actual development formulations.
Potential method claims for HIV treatment.

Its weaknesses are:

No apparent compound-level protection.
No express coverage of prophylaxis.
Dependence on proving a performance limitation.
Use of common excipients that may be vulnerable to obviousness attacks.
Uncertain Orange Book relevance without listing confirmation.
Potentially ambiguous degradation-testing language.
Straightforward formulation-design-around opportunities.

Key Takeaways

Patent 9,457,036 protects specific TDF/FTC tablet formulations, not TDF or FTC as chemical entities.
Claims 1 and 16 require 300 mg TDF, 200 mg FTC, listed excipient categories, tablet form, and no more than 5% degradation after six months under specified accelerated conditions.
Claims 5 through 11 add narrower excipient and quantitative formulations, including approximately 1,000 mg tablets.
Claims 13 and 14 cover treatment of HIV infection but depend on the underlying formulation claims and do not expressly cover prophylaxis.
The patent’s commercial strength depends heavily on Orange Book listing, ownership, expiration, and the ability to prove the stability limitation.
Generic manufacturers have plausible design-around strategies using different excipient classes or formulations that fail the claimed performance limitation.
The patent creates generic formulation risk, not biosimilar risk.
Exact patent expiration and current litigation status cannot be established from the claim text alone.

FAQs About U.S. Patent 9,457,036

Does Patent 9,457,036 cover Truvada itself?

It may overlap with a Truvada-like formulation, but the claims do not cover every Truvada product automatically. The accused product must satisfy the specified excipient, tablet, dose, and stability limitations.

Can a generic use 300 mg TDF and 200 mg FTC without infringing?

Yes, potentially. Using the same active strengths alone does not establish infringement. The generic must also be evaluated against the binder, disintegrant, lubricant, tablet, stability, and impurity limitations.

Does the patent cover HIV pre-exposure prophylaxis?

The supplied method claims refer to treatment of symptoms or effects of an HIV infection. They do not expressly recite prevention in an uninfected person.

Are claims 2 through 4 commercially important?

They may provide narrow fallback protection, but their value depends on whether the patent specification defines a reproducible 24-hour degradation test and whether a competing product meets the unusually low degradation thresholds.

Can a manufacturer avoid the patent by adding another excipient?

Not necessarily. Because the claims use “comprising,” adding an ingredient does not remove existing claimed ingredients. The manufacturer generally must omit or replace a required element or establish that the stability or other limitations are not met.

References

U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
U.S. Food and Drug Administration. (2024). Truvada prescribing information. Gilead Sciences, Inc.
United States Patent and Trademark Office. (2024). Patent term adjustment and patent term extension guidance.
21 U.S.C. § 355(j); 35 U.S.C. §§ 154, 156.
United States Patent No. 9,457,036, claims 1-16. (2016).

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
African Regional IP Organization (ARIPO)	2089	⤷ Start Trial
Argentina	040805	⤷ Start Trial
Argentina	043332	⤷ Start Trial
Argentina	101679	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 9,457,036

Summary for Patent: 9,457,036