US Patent 8,716,264: Claim Scope, Patent Strength, Exclusivity and Generic Entry Analysis

US Patent 8,716,264 protects specific chemically stable fixed-dose oral combinations containing 300 mg tenofovir disoproxil fumarate and 200 mg emtricitabine, corresponding to the active-ingredient strengths in Truvada. Its strongest protection is directed to stability performance and specified excipient formulations, rather than to tenofovir disoproxil fumarate, emtricitabine, or the combination at large. The patent does not claim the active ingredients as chemical compounds.

The principal commercial risk depends on whether a competing product reproduces the claimed 300 mg/200 mg combination, satisfies the functional stability limitations, or uses one of the recited excipient compositions. Because several claims require proof of degradation levels under particular storage conditions, infringement and validity disputes would likely turn on analytical testing, claim construction, and whether the stability limitations are treated as enforceable product limitations.

What does US Patent 8,716,264 claim?

The patent has four principal claim groups:

Claim group	Claims	Core subject matter
Stability-defined fixed-dose combination	1-17	300 mg tenofovir disoproxil fumarate plus 200 mg emtricitabine meeting degradation thresholds
Specific formulations	18-24	The active ingredients combined with defined excipients and, in some claims, specified quantities
Impurity limitation	25	Less than 1% of impurities related to the two active ingredients
Combination and method-of-use claims	26-38	A third antiviral agent and treatment of HIV infection

Independent claim 1 is the broadest principal composition claim. It requires:

A chemically stable fixed-dose combination.
300 mg tenofovir disoproxil fumarate.
200 mg emtricitabine.
Less than 10% degradation of both active ingredients after six months.
A specified accelerated-storage and packaging condition involving silica gel desiccant.

Claim 10 provides a separate stability route. It requires less than 10% degradation of tenofovir disoproxil fumarate over a 24-hour period, without expressly including the six-month stability condition in the independent claim.

The claims therefore focus on the physical and chemical performance of a finished product. They do not broadly cover every product containing tenofovir disoproxil fumarate and emtricitabine.

How narrow is the 300 mg tenofovir and 200 mg emtricitabine limitation?

The exact dosage strengths materially narrow the claims. A product containing 300 mg tenofovir disoproxil fumarate and 200 mg emtricitabine would fall within the numerical limitation if the amounts are measured as claimed and the other elements are satisfied.

The following products would present different claim-scope issues:

Competing product configuration	Risk under claims 1-17
300 mg TDF/200 mg FTC tablet	High if the stability limitations are met
300 mg TDF/200 mg FTC capsule	Potentially high because claims 2 and 3 cover dosage forms and oral forms
Different TDF or FTC strength	Lower under the literal numerical limitations
Separate TDF and FTC tablets	Lower for fixed-dose-combination claims
TAF/FTC product	Outside the express TDF limitation
FTC with a third antiviral	Potentially within claims 26-32 if the 300 mg/200 mg base combination and other limitations are present
Product with different excipients	Possible exposure under claims 1-17, but reduced exposure under claims 18-24

The claims do not expressly require a tablet in every case. Claims 2 and 11 refer to a pharmaceutical dosage form, while claim 3 specifies an oral dosage form. A non-tablet oral dosage form could therefore raise infringement issues if it otherwise satisfies the claimed composition and stability conditions.

What stability requirements must a product satisfy?

The patent uses several degradation thresholds:

Claims	Stability limitation
1	Less than 10% degradation of TDF and FTC after six months under specified conditions
5	Less than 10% TDF degradation over 24 hours
6	Less than 1% TDF degradation over 24 hours
7	Less than 0.1% TDF degradation over 24 hours
8	Less than 0.01% TDF degradation over 24 hours
9	Less than 5% degradation of TDF and FTC after six months
10	Less than 10% TDF degradation over 24 hours
13-15	Less than 1%, 0.1%, or 0.01% TDF degradation
16	Less than 10% degradation of TDF and FTC after six months
17	Less than 5% degradation of TDF and FTC after six months
25	Less than 1% impurities related to TDF and FTC

Claims 1, 9, 16 and 17 use the six-month stability test. Claims 5-8 and 10, 13-15 use a 24-hour degradation limitation. The claim language supplied does not define all analytical details, including the assay method, baseline measurement, treatment of individual impurities, or whether degradation is calculated by mass balance, assay loss, or specified degradation products.

Those details would be important in a litigation setting. A manufacturer could dispute whether a test result satisfies the claim if the patent specification does not provide a sufficiently precise testing protocol. The functional limitations also create potential enablement, written-description, indefiniteness, and infringement issues under 35 U.S.C. §§ 112 and 271.

What formulations are protected by US 8,716,264?

Claims 18-24 create narrower formulation protections.

Claims 18-22: starch, lactose, cellulose and silica formulations

Claim 18 requires:

300 mg TDF;
200 mg FTC;
pregelatinized starch;
croscarmellose sodium;
lactose monohydrate;
microcrystalline cellulose; and
magnesium stearate.

Claims 19 and 20 specify alternative quantities:

Claim	Pregelatinized starch	Croscarmellose sodium	Lactose monohydrate	Microcrystalline cellulose	Magnesium stearate
19	50 mg	60 mg	80 mg	300 mg	10 mg
20	50 mg	60 mg	180 mg	200 mg	10 mg

Claim 21 adds colloidal silicon dioxide to the excipient group. Claim 22 specifies 175 mg lactose monohydrate, 200 mg microcrystalline cellulose, 10 mg magnesium stearate, 50 mg pregelatinized starch, 60 mg croscarmellose sodium and 5 mg colloidal silicon dioxide.

These claims are vulnerable to design-around strategies involving different fillers, binders, disintegrants, glidants, lubricants, or quantities. A product that omits one required excipient would generally avoid literal infringement of the corresponding closed-list composition claim, subject to the doctrine of equivalents.

Claims 23-24: hydroxypropyl methylcellulose formulation

Claim 23 requires HPMC, lactose B.P., pregelatinized starch B.P. and magnesium stearate. Claim 24 specifies quantities but, as supplied, recites “112 g hydroxypropyl methylcellulose” in a dosage-form context that otherwise uses milligram quantities.

That “112 g” term raises a material claim-construction issue. It may be a transcription or drafting error, but a court would not automatically correct it. If the patent’s issued text actually contains “112 g,” the limitation may be commercially impractical or internally inconsistent. If the issued patent contains “112 mg” and the supplied text is inaccurate, the analysis changes. The quoted claim text alone does not resolve the issue.

How do claims 26-32 expand the patent?

Claims 26-32 extend the formulation claims to products containing a third antiviral agent. The third agent may be:

A protease inhibitor;
A nucleoside reverse transcriptase inhibitor;
A non-nucleoside reverse transcriptase inhibitor; or
An integrase inhibitor.

Claim 32 specifically identifies efavirenz.

These claims do not independently claim any three-drug antiretroviral product. They depend on the underlying pharmaceutical dosage form and therefore remain tied to the 300 mg TDF/200 mg FTC combination. A third-agent product would need to satisfy the base claim limitations, including the relevant dosage form and any incorporated stability or formulation requirements.

The broad category claims may face prior-art and written-description scrutiny because antiviral classes contain numerous compounds with materially different physicochemical properties. Claim 32 is commercially more concrete because it identifies efavirenz, but it is also narrower.

What do the HIV method-of-use claims protect?

Claims 33-38 cover administering the claimed dosage forms to an infected animal to treat symptoms or effects of HIV infection.

These claims are narrower than a general HIV-treatment claim because they depend on particular composition claims:

Claims	Covered treatment product
33	Dosage form of claim 2 or 11
34	Dosage form of claim 9 or 13
35	Dosage form of claim 21
36	Dosage form of claim 26
37	Dosage form of claim 27
38	Dosage form of claim 32

The use of “animal” is broader than “human” as a literal matter, but commercial enforcement would focus on human pharmaceutical products. Method claims may be relevant to induced infringement, labeling, prescribing instructions, and ANDA litigation under 35 U.S.C. § 271(e)(2), although the practical value depends on the approved labeling and the precise claim dependencies.

When does US Patent 8,716,264 lose exclusivity?

A reliable patent-expiration analysis requires the patent’s earliest effective nonprovisional priority date, patent-term-adjustment calculation, terminal disclaimers, reexamination history, and any post-grant legal events. Those details are not contained in the supplied claims.

The statutory framework is generally:

Utility patents with applications filed on or after June 8, 1995 receive a term of 20 years from the earliest effective nonprovisional filing date.
Patent-term adjustment may extend the term.
Patent-term extension under 35 U.S.C. § 156 may apply to regulatory delay, subject to statutory limits.
A terminal disclaimer can shorten the enforceable term.
Patent expiration is separate from FDA regulatory exclusivity.

The issue is especially important for US 8,716,264 because tenofovir disoproxil fumarate and emtricitabine are old active ingredients, while this patent appears directed to a later fixed-dose formulation and stability concept. The patent’s enforceable term may therefore extend beyond the basic compound-patent terms, but the actual expiration date cannot be established from the claims alone.

What is the Orange Book status of US 8,716,264?

The Orange Book lists patents submitted by NDA sponsors for approved drug products. Listing depends on the relationship between the patent claims and the approved product, not merely on the existence of a patent.

For a fixed-dose product such as Truvada, relevant Orange Book categories may include:

Drug-substance patents;
Drug-product patents;
Method-of-use patents; and
Formulation or dosage-form patents.

The supplied claims do not establish whether US 8,716,264 was listed for Truvada, whether it remains listed, or whether it was delisted. Those facts must be confirmed through the FDA’s current Approved Drug Products with Therapeutic Equivalence Evaluations database and the relevant NDA patent submissions. The FDA Orange Book determines the regulatory effect of a listed patent, while the USPTO and court records determine patent validity, enforceability, ownership and expiration.

Which companies are likely to challenge the patent?

Generic manufacturers of TDF/FTC fixed-dose products are the relevant potential challengers. The competitive field has included large generic and international manufacturers such as Teva, Viatris or Mylan, Cipla, Hetero, Lupin and other ANDA sponsors.

A complete Paragraph IV analysis must distinguish among:

A Paragraph IV certification against this specific patent.
A Paragraph III certification accepting the patent’s expiration.
A section viii statement carving out a method of use.
A settlement or license permitting an authorized generic or delayed launch.
A product that avoids the listed patent through a different formulation or packaging design.

The claim text does not identify any ANDA filer, certification, district-court action, Federal Circuit appeal, settlement agreement or authorized-generic license. It therefore cannot establish which companies challenged US 8,716,264 or whether any challenge remains active.

What generic launch risks arise from the patent?

Literal infringement risk

The highest literal risk applies to a product that:

Contains exactly 300 mg TDF and 200 mg FTC;
Is supplied as a fixed-dose oral dosage form;
Meets the six-month degradation limits;
Uses silica gel desiccant in the claimed storage configuration; or
Reproduces a claimed excipient formula.

Design-around risk

Potential design-around options include:

Using a different dose strength;
Separating the two active ingredients;
Replacing TDF with tenofovir alafenamide;
Changing the excipient system;
Omitting colloidal silicon dioxide;
Using a different packaging or moisture-control system;
Modifying the formulation so that the claimed stability thresholds are not met, while still satisfying FDA specifications.

The last strategy is commercially limited. A generic applicant must still meet applicable stability, quality and bioequivalence requirements. Avoiding a patent limitation cannot justify a product that fails FDA standards.

Paragraph IV litigation risk

If the patent is listed for the reference product and has not expired, an ANDA applicant making the 300 mg/200 mg product may face a 30-month stay under the Hatch-Waxman framework if the NDA holder timely files an infringement action after receiving a Paragraph IV notice. The stay and litigation consequences depend on the listing date, certification timing, statutory notices and court action.

How strong is the patent estate?

The patent has mixed strength by claim category.

Claim category	Relative strength	Main reason
Claims 1-4	Moderate	Broadest composition and dosage-form coverage, but dependent on functional stability
Claims 5-8	Narrow to moderate	Strong numerical thresholds, but testing and construction issues
Claims 9-17	Moderate	Alternative stability limitations provide multiple enforcement paths
Claims 18-24	Potentially strong against exact copies	Specific excipient combinations are easier to prove but easier to design around
Claim 25	Moderate	Impurity threshold may be difficult to interpret and prove
Claims 26-32	Narrow to moderate	Third-agent coverage depends on the base formulation
Claims 33-38	Narrow	Method claims incorporate multiple composition limitations

The estate’s commercial strength is likely concentrated in formulation and stability protection. Its value is lower against products that use a different active-ingredient form, dosage strength, excipient architecture, or packaging system.

What licensing and settlement issues matter?

A patent license may permit:

Earlier generic entry;
An authorized generic launch;
Geographic limitations;
A product-specific formulation;
A waiver of damages for past sales;
A covenant not to sue; or
Entry tied to a specified patent expiration date.

A settlement involving other TDF/FTC patents does not automatically resolve US 8,716,264. Each patent must be assessed separately unless the agreement expressly covers the patent by number, family, continuations, or defined patent rights. The supplied information contains no licensing or settlement terms.

Does the patent create biosimilar risk?

No conventional biosimilar pathway applies. TDF/FTC is a small-molecule fixed-dose combination, not a biologic. The relevant competitors would generally use ANDAs under section 505(j) of the Federal Food, Drug, and Cosmetic Act, not abbreviated biosimilar applications under the Public Health Service Act.

The principal regulatory competition issues are generic bioequivalence, formulation similarity where required, stability, labeling, impurity control and patent certification.

Key Takeaways

US 8,716,264 targets a stable 300 mg TDF/200 mg FTC fixed-dose product.
It does not claim tenofovir disoproxil fumarate or emtricitabine as chemical compounds.
The most important limitations are degradation thresholds, packaging and storage conditions, and exact excipient combinations.
Claims 18-24 provide narrower protection that may be easier to design around.
Claims 26-32 cover selected three-drug products, including efavirenz combinations, but remain dependent on the base TDF/FTC formulation.
Claims 33-38 are treatment claims tied to the composition claims.
The quoted “112 g” quantity in claim 24 creates a potentially significant claim-construction issue.
The supplied claims do not establish the patent’s expiration date, Orange Book status, Paragraph IV history, litigation record, licensing terms or settlement status.
Generic entry risk is highest for an exact 300 mg/200 mg oral copy using the claimed formulation and stability profile.
Biosimilar risk is not applicable; the relevant competitors are ANDA filers.

FAQs About US Patent 8,716,264

Does US 8,716,264 cover Truvada itself?

It may cover certain Truvada-type fixed-dose formulations if the product satisfies the claimed dosage, stability and formulation limitations. The claims do not cover every product containing TDF and FTC.

Can a generic avoid the patent by changing the excipients?

Potentially. Changing an excipient may avoid claims 18-24, but it would not necessarily avoid claims 1-17, which focus principally on active-ingredient strengths and stability performance.

Is claim 25 an impurity patent?

Claim 25 is an impurity-limited dosage-form claim. It requires less than 1% of impurities related to TDF and FTC, but the precise measurement and impurity definition would be central to enforcement.

Are TAF/emtricitabine products within the claims?

Not literally based on the supplied claims. The claims require tenofovir disoproxil fumarate, not tenofovir alafenamide.

Does a different package avoid the patent?

A different package may avoid a claim requiring silica gel desiccant and the specified storage condition. It would not automatically avoid claims that do not include that packaging limitation.

References

United States Patent and Trademark Office. (2014). US Patent No. 8,716,264 B2: Claims supplied by the requester.
U.S. Food and Drug Administration. (2004). Truvada prescribing information. FDA.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations. FDA Orange Book.
United States Code. 35 U.S.C. §§ 101, 112, 156, 271 and 282.
United States Code. 21 U.S.C. § 355.

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
Austria	398455	⤷ Start Trial
Australia	2004206821	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 8,716,264

Summary for Patent: 8,716,264