US Patent 10,786,518: Scope, Claims, Expiration and Patent Landscape for Symtuza

US Patent 10,786,518 protects a specific treatment-switch method using the once-daily, fixed-dose combination of darunavir, cobicistat, emtricitabine and tenofovir alafenamide. The patent is directed to treatment-experienced HIV patients who switch from a prior antiretroviral regimen and maintain virologic suppression. It does not broadly claim the Symtuza composition, the individual active ingredients, or every use of the product.

The patent’s commercial significance is concentrated in method-of-use protection for Symtuza, marketed by Janssen and Gilead. Its principal independent claim requires all of the following:

Oral administration once daily.
A single unit dosage form.
Darunavir, cobicistat, emtricitabine and tenofovir alafenamide.
A treatment-experienced HIV-infected subject.
Discontinuation of a first antiretroviral regimen.
HIV-1 viral load of 50 copies/mL or less after at least 24 weeks of treatment.

The nominal patent term extends into 2035, subject to any applicable patent-term adjustment. The patent is relevant to generic versions of Symtuza, but its narrow outcome-based method claims create design-around and non-infringement opportunities.

What does US Patent 10,786,518 cover?

US Patent 10,786,518 covers the clinical use of a four-drug, fixed-dose regimen for switching treatment-experienced patients from an earlier antiretroviral regimen while maintaining viral suppression.

The claimed combination corresponds to Symtuza, which contains:

Component	Claimed or commercial amount
Darunavir	About 800 mg
Cobicistat	About 150 mg
Emtricitabine	About 200 mg
Tenofovir alafenamide	About 10 mg
Tenofovir alafenamide fumarate	About 11.2 mg, corresponding to about 10 mg TAF

The patent does not require the product to be called Symtuza. Infringement would depend on whether an accused product and treatment protocol satisfy the claim limitations, regardless of branding.

The patent covers both the active pharmaceutical ingredients and specified patient-treatment conditions. It is therefore a method-of-use patent rather than a basic composition-of-matter patent.

What are the key limitations of claim 1?

Claim 1 is the central claim. Each limitation narrows the protected method.

Fixed-dose single-tablet administration

The regimen must be administered as a single unit dosage form. A patient receiving separate darunavir, cobicistat, emtricitabine and TAF tablets would not literally satisfy this limitation unless a court treated the separate products as equivalent under the doctrine of equivalents.

The claim also requires once-daily oral administration. A twice-daily regimen, injectable regimen or regimen using multiple daily units would fall outside the literal language.

Specific four-drug combination

The dosage form must contain:

Darunavir, or a hydrate or solvate;
Cobicistat;
Emtricitabine; and
TAF, or a pharmaceutically acceptable salt.

The dependent claims expressly identify darunavir ethanolate and TAF fumarate or hemifumarate. Claim 20 corresponds to the commercial TAF fumarate amount used in Symtuza.

Treatment-experienced patient

The patient must have received and discontinued a first antiretroviral regimen. This limitation distinguishes the patent from claims directed to treatment-naive patients.

The prior regimen may include a boosted protease inhibitor and nucleoside or nucleotide reverse-transcriptase inhibitors. Claim 6 lists prior regimens based on:

Darunavir and ritonavir;
Darunavir and cobicistat;
Atazanavir and ritonavir;
Atazanavir and cobicistat; or
Lopinavir and ritonavir.

Claim 7 specifically identifies prior use of tenofovir disoproxil fumarate.

Virologic suppression after treatment

The patient must exhibit HIV-1 viral load of 50 copies/mL or less after at least 24 weeks of once-daily administration. Claims 21 and 22 extend the relevant follow-up periods to at least 48 and 96 weeks.

This outcome limitation is commercially important. A generic applicant may argue that its product label does not direct physicians to use the product in the claimed switch population or that the claimed virologic result is not an instruction or required condition of the approved use.

How do claims 2 through 25 expand the patent scope?

Claims	Subject matter
2	Darunavir ethanolate
3	TAF fumarate
4	TAF hemifumarate
5-7	Prior antiretroviral regimens, including boosted protease inhibitor regimens and TDF
8	Administration with food
9	HIV-1 infection
10	No darunavir resistance-associated mutations or K65R mutation
11	Presence of darunavir resistance-associated mutations or K65R mutation
12	Child-Pugh Class A or B hepatic impairment
13-14	Absence or presence of detectable hepatitis B virus
15	Viral suppression before switching
16-20	Specific active-ingredient quantities
21-22	Viral suppression after 48 or 96 weeks
23	Maintained or improved CD4+ cell count
24	No emergent resistance-associated mutation
25	Tenofovir disoproxil or tenofovir disoproxil fumarate in the prior regimen

Claims 10 and 11 are drafted as alternative patient populations. Claim 10 covers patients without the specified resistance markers. Claim 11 covers patients with those markers. These claims attempt to capture both resistance-negative and resistance-positive subgroups, although clinical-label, enablement and written-description issues could arise depending on the prosecution record and supporting data.

Claims 13 and 14 similarly address patients with and without detectable hepatitis B virus. Because emtricitabine and TAF have anti-hepatitis B activity, these limitations expand the treatment population but do not claim hepatitis B treatment independently of HIV treatment.

What drug is associated with US Patent 10,786,518?

The patent is principally associated with Symtuza, the fixed-dose combination of darunavir, cobicistat, emtricitabine and TAF.

Symtuza received FDA approval in July 2018 as a complete regimen for the treatment of HIV-1 infection in adults and pediatric patients meeting the applicable weight and age requirements. The product label identifies the four active ingredients and instructs administration once daily with food.[2]

The claimed dosage strength is:

Product	Strength
Symtuza	Darunavir 800 mg, cobicistat 150 mg, emtricitabine 200 mg and TAF 10 mg

The patent’s switch-treatment profile is consistent with clinical development of Symtuza in virologically suppressed, treatment-experienced patients. The patent does not itself establish FDA approval for every claimed subgroup.

What is the patent expiration date?

The patent has a nominal term extending to approximately March 2035, based on the earliest relevant nonprovisional filing date and the 20-year US patent-term framework. The exact enforceable expiration date depends on the patent’s terminal-disclaimer status and any patent-term adjustment recorded by the USPTO.[1]

Event	Date or status
US patent	10,786,518
Issue date	September 22, 2020
Patent type	Method-of-use
Principal product	Symtuza
Nominal expiration	Approximately March 2035
Patent-term adjustment	Must be confirmed from the USPTO patent record
Patent-term extension	No extension should be assumed without a recorded USPTO or FDA determination

A patent’s nominal expiration date is not the same as guaranteed market exclusivity. An ANDA applicant may challenge validity, enforceability or infringement before expiration. Conversely, a patent may provide limited practical protection if its claims are difficult to prove against a generic label or actual prescribing practices.

What is the Orange Book status of US Patent 10,786,518?

US Patent 10,786,518 is associated with the Symtuza regulatory patent estate and may be relevant to an Orange Book-listed method-of-use patent assessment. Orange Book status should be evaluated using the current FDA Approved Drug Products with Therapeutic Equivalence Evaluations database, including the listed patent-use code and any later delisting or expiration update.[3]

Orange Book relevance depends on:

Whether the patent is listed against Symtuza’s NDA;
The use code assigned by FDA;
Whether the claimed method corresponds to an approved indication;
Whether the patent has been delisted, expired or disclaimed;
Whether a generic applicant must certify under Paragraph IV.

A method patent can trigger a Paragraph IV certification even when it does not cover the active ingredients or tablet formulation as such. A generic applicant may instead use a section viii statement to carve out a patented method, but that route depends on whether the patented use can be omitted from the proposed labeling.

When does Symtuza lose exclusivity?

Symtuza’s regulatory exclusivity and patent exclusivity arise from separate mechanisms.

Exclusivity type	Approximate status
FDA approval	July 2018
New chemical entity exclusivity	Unlikely for the fixed-dose combination because the active ingredients were previously approved
Three-year clinical-investigation exclusivity	Potentially applicable to the new combination or new indication
Pediatric exclusivity	Depends on FDA-recognized completion of pediatric obligations
US patent 10,786,518	Nominally extends to about March 2035
Generic entry	Could occur before patent expiration through settlement, successful challenge, carve-out or non-infringing labeling

The four active ingredients had extensive prior approval histories. As a result, Symtuza’s regulatory exclusivity is principally distinct from the patent protection for its fixed-dose combination and clinical use.

How strong is the patent estate for Symtuza?

The Symtuza patent estate has multiple layers, but US Patent 10,786,518 is narrower than a composition patent.

Stronger protection

The patent is stronger against a generic product that:

Contains all four active ingredients in one tablet;
Is labeled for once-daily administration;
Is directed to treatment-experienced, virologically suppressed patients;
Identifies switching from prior boosted protease inhibitor therapy;
Includes the relevant viral suppression and follow-up language.

The combination of product-specific ingredients, dose amounts, patient history and clinical outcome limits creates a dense claim set for the approved use.

Weaker protection

The patent is weaker against:

Separate-tablet regimens;
Products labeled only for treatment-naive patients;
Products with a section viii carve-out for treatment-experienced switching;
Products whose labels omit the patented clinical outcome;
Prescribing outside the patented treatment instructions;
Products that do not use a single unit dosage form.

Method claims also depend on proof that the accused conduct occurred. A generic manufacturer generally does not directly administer the drug to patients. The litigation theory may instead focus on induced infringement through labeling, marketing, distribution and physician instructions.

What Paragraph IV challenges could affect this patent?

A Paragraph IV certification would assert that the patent is invalid, unenforceable or not infringed. A generic applicant could challenge US Patent 10,786,518 on several grounds:

Lack of novelty based on earlier switch-regimen disclosures.
Obviousness based on known combinations of darunavir, cobicistat, emtricitabine and TAF.
Written-description or enablement challenges to the broad patient subgroups.
Indefiniteness involving viral-load, resistance and treatment-history limitations.
Non-infringement based on omission of the patented use from the label.
Failure to prove induced infringement from the proposed generic labeling.

The most material issue is likely the interaction between the approved label and the claim’s treatment-experienced switch limitations. A generic applicant may seek approval while excluding the patented use under a section viii statement. That strategy is more viable if the FDA label can be divided cleanly between unpatented and patented uses.

No biosimilar pathway applies. Symtuza is a small-molecule fixed-dose combination, so competing products would generally proceed through an ANDA or, in some circumstances, a 505(b)(2) application rather than a biosimilar application.

What patent litigation and settlement risks exist?

A generic challenge could generate litigation under the Hatch-Waxman Act after the NDA holder receives a Paragraph IV notice. The likely defendants would include the NDA holder and patent owners or exclusive licensees associated with the Symtuza product and its components.

Potential settlement structures include:

A delayed generic launch before the nominal 2035 expiration date;
A licensed entry date;
A covenant not to sue for specified uses;
A label carve-out;
An authorized generic arrangement;
A resolution limited to particular patents in the Symtuza estate.

The commercial effect depends on whether US Patent 10,786,518 is the last enforceable patent blocking the intended generic label. If earlier composition, formulation or manufacturing patents remain in force, a successful challenge to this method patent may not produce immediate market entry.

How does US Patent 10,786,518 compare with formulation and manufacturing patents?

US Patent 10,786,518 is primarily a clinical-use patent. It does not appear from the supplied claims to protect:

A specific tablet excipient system;
A particular coating;
A manufacturing process;
A polymorph or crystal form;
A dissolution profile;
A tablet hardness or stability specification;
A process for manufacturing darunavir, cobicistat, emtricitabine or TAF.

Formulation and manufacturing patents can be more difficult to design around if they cover the commercial tablet architecture or a necessary process. By contrast, a method-of-use patent can often be attacked through labeling, patient-population restrictions or non-infringing administration instructions.

The patent’s geographic protection is limited to the United States. Parallel patent families may exist in Europe, Canada, Japan and other jurisdictions, but their claims, expiration dates and enforceability are independent.

What generic launch scenarios are most likely?

Scenario	Commercial consequence
Patent upheld and label covers the claimed switch use	Generic launch delayed until expiration or settlement date
Patent invalidated	Earlier launch possible, subject to other Symtuza patents
Section viii carve-out accepted	Generic may launch with omitted treatment-experienced use
Product is not a single fixed-dose unit	Lower literal infringement risk
Earlier formulation patent remains enforceable	Challenge to 10,786,518 may not enable launch
Settlement reached	Entry date and commercial terms control market timing

The most relevant competitive risk is not a biosimilar substitution event. It is an ANDA-based generic fixed-dose combination containing the same four active ingredients, potentially launched after patent litigation or under a negotiated license.

What is the revenue exposure from this patent?

The patent can protect a substantial portion of Symtuza sales because the claimed regimen corresponds to a commercially important switch population. Its revenue value depends on:

The share of Symtuza prescriptions in treatment-experienced patients;
Whether physicians use the product in patients with prior boosted protease inhibitor therapy;
The number and strength of other listed patents;
The timing of generic entry;
Payer substitution and discounting after launch;
Whether a generic can obtain approval with a treatment-use carve-out.

The patent does not independently protect all Symtuza revenue. Patients outside the claimed population, prescriptions for non-infringing uses and products with carved-out labeling may remain outside its practical scope.

Key Takeaways

US Patent 10,786,518 is a method-of-use patent associated with the Symtuza four-drug HIV regimen.
Claim 1 requires a once-daily, orally administered, single-unit dosage form containing darunavir, cobicistat, emtricitabine and TAF.
The patient must be treatment-experienced and must have discontinued a prior antiretroviral regimen.
The claim requires HIV-1 viral suppression of 50 copies/mL or less after at least 24 weeks.
Dependent claims cover Symtuza-equivalent strengths, darunavir ethanolate, TAF fumarate, TAF hemifumarate, prior TDF use, resistance mutations, hepatic impairment and hepatitis B status.
The nominal patent term extends to approximately March 2035, subject to USPTO patent-term adjustment and other term records.
The patent is vulnerable to section viii carve-outs, non-infringement arguments and challenges to the clinical outcome limitations.
No biosimilar pathway applies because Symtuza is a small-molecule fixed-dose combination.
Generic entry will depend on the entire Symtuza patent estate, not this patent alone.

FAQs

Does US Patent 10,786,518 cover the Symtuza tablet itself?

No. The supplied claims cover a treatment method using a single-unit dosage form. They do not independently claim the tablet composition, excipients or manufacturing process.

Can a generic launch with the same four active ingredients?

Potentially. Launch timing would depend on Orange Book certifications, patent litigation, any section viii label carve-out, other Symtuza patents and settlement terms.

Does the patent cover treatment-naive HIV patients?

The principal claim requires a treatment-experienced patient who discontinued a first antiretroviral regimen. Treatment-naive patients fall outside that express limitation.

Is tenofovir disoproxil fumarate protected as part of the claimed product?

No. TDF appears in claims 7 and 25 as part of the patient’s prior regimen. The claimed once-daily fixed-dose product contains TAF, not TDF.

Does the patent cover HIV-2 treatment?

Claim 9 specifies HIV-1. The supplied claims do not expressly extend protection to HIV-2 infection.

References

United States Patent and Trademark Office. (2020). US Patent No. 10,786,518, treatment of HIV infection with a combination of antiretroviral agents.
U.S. Food and Drug Administration. (2018). Symtuza prescribing information.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, Orange Book.
United States Patent and Trademark Office. (n.d.). Patent term adjustment and patent term calculation resources.
U.S. Food and Drug Administration. (2024). Orange Book: Approved drug products with therapeutic equivalence evaluations, patent and exclusivity information.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Janssen Prods	SYMTUZA	cobicistat; darunavir; emtricitabine; tenofovir alafenamide fumarate	TABLET;ORAL	210455-001	Jul 17, 2018		RX	Yes	Yes	⤷ Start Trial	⤷ Start Trial				TREATMENT OF HIV-1 INFECTION IN ADULT OR PEDIATRIC PATIENTS (>=40 KG) WITH = 6 MONTHS ON PRIOR ANTIRETROVIRAL REGIMEN AND NO KNOWN DARUNAVIR OR TENOFOVIR RESISTANCE-ASSOCIATED SUBSTITUTIONS	⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2018304373	⤷ Start Trial
Brazil	112020000842	⤷ Start Trial
Canada	3070713	⤷ Start Trial
Chile	2020000136	⤷ Start Trial
Denmark	3654951	⤷ Start Trial
European Patent Office	3654951	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 10,786,518

Which drugs does patent 10,786,518 protect, and when does it expire?

Summary for Patent: 10,786,518