ISENTRESS Drug Patent Profile

Which patents cover Isentress, and when can generic versions of Isentress launch?

Isentress is a drug marketed by Msd Sub Merck and is included in three NDAs. There are five patents protecting this drug.

This drug has seventy-six patent family members in thirty-seven countries.

The generic ingredient in ISENTRESS is raltegravir potassium. There are five drug master file entries for this compound. Five suppliers are listed for this compound. Additional details are available on the raltegravir potassium profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Isentress

A generic version of ISENTRESS was approved as raltegravir potassium by LUPIN on May 6^th, 2025.

Summary for ISENTRESS

International Patents:	76
US Patents:	3
Applicants:	1
NDAs:	3
Finished Product Suppliers / Packagers:	4
Raw Ingredient (Bulk) Api Vendors:	76
Clinical Trials:	88
Patent Applications:	404
Drug Prices:	Drug price information for ISENTRESS
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for ISENTRESS
What excipients (inactive ingredients) are in ISENTRESS?	ISENTRESS excipients list
DailyMed Link:	ISENTRESS at DailyMed

See drug prices for ISENTRESS

Recent Clinical Trials for ISENTRESS

Identify potential brand extensions & 505(b)(2) entrants

Sponsor	Phase
St. Michael's Hospital, Toronto	Phase 2
Canadian Institutes of Health Research (CIHR)	Phase 2
Unity Health Toronto	Phase 2

See all ISENTRESS clinical trials

Pharmacology for ISENTRESS

Drug Class	Human Immunodeficiency Virus Integrase Strand Transfer Inhibitor
Mechanism of Action	HIV Integrase Inhibitors

US Patents and Regulatory Information for ISENTRESS

ISENTRESS is protected by three US patents.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Msd Sub Merck	ISENTRESS	raltegravir potassium	POWDER;ORAL	205786-001	Dec 20, 2013		RX	Yes	Yes					Y
Msd Sub Merck	ISENTRESS	raltegravir potassium	TABLET;ORAL	022145-001	Oct 12, 2007		RX	Yes	Yes					Y
Msd Sub Merck	ISENTRESS	raltegravir potassium	TABLET, CHEWABLE;ORAL	203045-002	Dec 21, 2011		RX	Yes	Yes					Y
Msd Sub Merck	ISENTRESS HD	raltegravir potassium	TABLET;ORAL	022145-002	May 26, 2017	AB	RX	Yes	Yes			Y	Y
Msd Sub Merck	ISENTRESS	raltegravir potassium	TABLET, CHEWABLE;ORAL	203045-001	Dec 21, 2011		RX	Yes	No					Y
Msd Sub Merck	ISENTRESS	raltegravir potassium	TABLET, CHEWABLE;ORAL	203045-002	Dec 21, 2011		RX	Yes	Yes			Y	Y
Msd Sub Merck	ISENTRESS	raltegravir potassium	TABLET;ORAL	022145-001	Oct 12, 2007		RX	Yes	Yes			Y	Y

International Patents for ISENTRESS

When does loss-of-exclusivity occur for ISENTRESS?

Based on analysis by DrugPatentWatch, the following patents block generic entry in the countries listed below:

Australia

Brazil

Canada

China

Colombia

Croatia

Cyprus

Denmark

European Patent Office

Hungary

India

Israel

Japan

Lithuania

Malaysia

Mexico

New Zealand

Poland

Portugal

Russian Federation

Serbia

Slovenia

South Africa

South Korea

Spain

Generics may enter earlier, or later, based on new patent filings, patent extensions, patent invalidation, early generic licensing, generic entry preferences, and other factors.

See the table below for additional patents covering ISENTRESS around the world.

Country	Patent Number	Title	Estimated Expiration
Austria	318140
Australia	2002334207
Brazil	0213522	compostos derivados de hidroxipirimidinona, composição farmacêutica, e, uso de um composto
Brazil	PI0213522	compostos derivados de hidroxipirimidinona, composição farmacêutica, e, uso de um composto
Canada	2463976	INHIBITEURS DE L'INTEGRASE DU VIH A BASE D'HYDROXYPYRIMIDINONE CARBOXAMIDE N-SUBSTITUE (N-SUBSTITUTED HYDROXYPYRIMIDINONE CARBOXAMIDE INHIBITORS OF HIV INTEGRASE)
China	102219750
China	102229605

Supplementary Protection Certificates for ISENTRESS

Patent Number	Supplementary Protection Certificate	SPC Country	SPC Expiration	SPC Description
1441735	CA 2008 00021	Denmark
1441735	91428	Luxembourg		PRODUCT NAME: RALTEGRAVIR (ISENTRESS ); AUTHORISATION NUMBER AND DATE: EU/1/07/436/01 20080102
1441735	C20080001 00016	Estonia		PRODUCT NAME: ISENTRESS; REG NO/DATE: 20.12.2007 C(2007)6801
1441735	PA2008007	Lithuania		PRODUCT NAME: RALTEGRAVIRUM; REG. NO/DATE: EU/1/07/436/001-002 20071220
1441735	20221021	Netherlands		20221021, EXPIRES: 20221219
1441735	PA2008007,C1441735	Lithuania		PRODUCT NAME: RALTEGRAVIRUM; REGISTRATION NO/DATE: EU/1/07/436/001, 2007 12 20 EU/1/07/436/002 20071220
1441735	C01441735/01	Switzerland		FORMER OWNER: ISTITUTO DI RICERCHE DI BIOLOGIA MOLECOLARE P. ANGELETTI S.P.A., IT

Last updated: July 21, 2026

ISENTRESS (raltegravir): Market dynamics and financial trajectory

Executive summary: ISENTRESS (raltegravir; Merck) is an entrenched, line-extension HIV integrase inhibitor with shrinking revenue influence in combination antiretroviral therapy (cART) as first-line regimens have shifted toward newer integrase inhibitors (notably bictegravir, dolutegravir) and long-acting strategies. Financial trajectory is driven by (1) sustained use in treatment-experienced and guideline-specified scenarios, (2) dosing convenience and formulary dynamics across fixed-dose combinations, (3) patent and exclusivity expiry and generic/biosimilar-like small-molecule competition risk (without biosimilars), (4) payer contracting and channel mix (retail vs specialty, US vs ex-US), and (5) the standalone vs combination product portfolio (notably ISENTRESS HD and the dual-drug extension with dolutegravir in newer markets via physician preference).

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What market factors drive ISENTRESS (raltegravir) demand in HIV treatment?

Featured snippet answer: ISENTRESS demand is shaped by guideline positioning for integrase inhibitors, payer formularies that steer toward preferred agents, resistance profiles, and the availability of newer once-daily regimens that compete in first-line and switch settings.

Guideline and regimen dynamics: how ISENTRESS wins and loses

• Core category: integrase strand transfer inhibitors (INSTIs) used in combination with other antiretroviral agents for HIV-1 suppression.
• Primary use case: when a patient regimen requires or favors an INSTI with known tolerability/resistance characteristics, including:
  • treatment-experienced patients with historical resistance patterns,
  • patients transitioning due to drug interactions,
  • pregnancy planning or safety-managed switches (regimen-specific).
• Competitive displacement: newer INSTIs with once-daily dosing and high barrier-to-resistance profiles have moved into preferred formulary slots, typically reducing incremental share growth for earlier entrants.

Payer and contracting: why gross-to-net matters more than list price

• Specialty pharmacy contracting and PBM rebates increasingly determine net price.
• Formularies tend to:
  • prefer once-daily options over twice-daily dosing where clinically appropriate,
  • prefer drugs with broader evidence within simplified single-tablet regimens,
  • tighten access when generics erode wholesaler price.

Country-level demand: US vs EU vs emerging markets

• US: slower decline in established patients but pressure from preferred INSTIs and generic entry dynamics across time.
• EU and other OECD: aggressive tendering and HTA-driven formulary restrictions can compress net revenue.
• Emerging markets: procurement mechanisms, generic penetration, and donor programs shape steady volumes but reduce value capture.

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When do ISENTRESS patents and exclusivity expire, and when does generics pressure peak?

Featured snippet answer: Patent and exclusivity timelines determine the calendar window for generic uptake; revenue typically compresses sharply after key US patent barriers fall and retail/specialty channels switch to lower-priced alternatives.

Key exclusivity and patent architecture that typically affects ISENTRESS value

For a mature small-molecule HIV drug, the revenue curve normally reflects:

• early composition-of-matter (C-M) protection that establishes initial exclusivity,
• later “evergreening” patents for dosage forms, high-dose variants, and specific combinations,
• method-of-use patents tied to specific patient populations or dosing regimens,
• manufacturing process patents that may delay certain generic manufacturing or label carve-outs.

Generic uptake mechanics after losses of exclusivity

• Paragraph IV filings (if any) can accelerate first generic entry when ANDA litigation settles or gaps narrow.
• Launch success depends on:
  • label acceptance and bioequivalence,
  • formulary switching cadence,
  • physician comfort and regimen stability concerns,
  • wholesale and specialty channel inventory turns.

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What is the Orange Book status of ISENTRESS, and how many patents block generic entry?

Featured snippet answer: Orange Book listing breadth (number of patents by submission type, including drug product, formulation, and method-of-use) determines the number of potential legal triggers and litigation “targets.”

Typical Orange Book patent categories for ISENTRESS-like products

• Drug substance (C-M) patents
• Drug product patents (formulation, polymorph, stability)
• Method of use (treatment indications)
• Patent life and expiration stagger can create piecemeal value erosion.

Practical impact on market competition

• Even after broad C-M expiry, remaining formulation or method-of-use patents can:
  • permit some generics while restricting full label substitution,
  • segment demand across indications and prescriber choices,
  • delay payer switching if clinical switching requires label alignment.

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What patent litigation affects ISENTRESS generic entry and settlement outcomes?

Featured snippet answer: Litigation affects timing of generic launch, which drives revenue step-down events and can create short-lived sales volatility around settlement and final court outcomes.

Litigation and settlement-driven pricing events

For established HIV drugs, revenue trajectory often shows discrete inflection points when:

• first generic launches enter (price compression),
• follow-on generics increase competition (additional rebate pressure),
• settlements resolve remaining barriers (label expansion and further switching).

How to read litigation impact in financial trajectory

• Look for:
  • sudden gross-to-net compression,
  • declining TRx and market share in the US where generic presence increases,
  • shifts from standalone formulations to preferred alternatives.

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How does ISENTRESS financial performance compare with competing INSTIs like dolutegravir and bictegravir?

Featured snippet answer: ISENTRESS competes within the INSTI class, but financial pressure increases as payers and physicians prioritize once-daily regimens and fixed-dose combinations that improve adherence and simplify treatment.

Direct competitive axis: dosing convenience and regimen simplification

• ISENTRESS dosing frequency (including HD variants) historically affects preference relative to once-daily INSTIs.
• Preferred regimen design reduces the likelihood of staying on older INSTIs unless there is a specific clinical reason.

Competitive axis: formulary tiering and switch rules

• Newer agents often enter as tier-1 on commercial formularies faster than older agents.
• Switch programs, patient stability criteria, and prior authorization policies influence displacement speed.

Financial exposure model used by investors

• ISENTRESS revenue typically tracks:
  • guideline adherence patterns,
  • new patient starts vs switch patients,
  • pricing erosion from generics and contract repricing,
  • portfolio cannibalization by company-owned newer INSTI assets (where applicable).

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What formulations are protected for ISENTRESS, and how do they affect generic launch timing?

Featured snippet answer: Formulation and dosage-form patents (including high-dose variants) can delay certain generic formulations even after core drug-substance protection ends.

Dosage-form and strength drivers

• High-dose regimens and specific oral dosing formats can have distinct patent “islands.”
• Generic applicants must align:
  • strength-specific formulations,
  • dissolution and bioequivalence profiles,
  • label and method-of-use statements.

Manufacturing and process considerations

• Process patents and facility know-how can affect:
  • manufacturing scale-up timelines,
  • regulatory approval speed,
  • market timing for first-to-file and subsequent ANDAs.

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What is the FDA regulatory status of ISENTRESS, and what label events matter commercially?

Featured snippet answer: FDA label status determines eligible patient populations for prescribing, which directly impacts TRx and revenue resilience even in a commoditizing environment.

Regulatory milestones that affect revenue

• Initial approval and subsequent label expansions:
  • pediatric age ranges,
  • regimen combinations,
  • dosing schedules (including high-dose approaches).
• Safety communications and labeling changes can shift adoption or sustain use in specific subpopulations.

How label scope influences payer behavior

• If a drug maintains broad label coverage:
  • it remains clinically usable across more scenarios,
  • payers find it easier to justify continued coverage during competitive periods.

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How strong is the ISENTRESS patent estate, and what does that imply for revenue durability?

Featured snippet answer: The patent estate strength for an older HIV drug is usually strongest for specific late-life islands (formulation and method-of-use) and weakest for genericable drug substance; revenue durability typically declines once key islands expire and label barriers fall.

Strength indicators used in licensing and litigation

• Number of active patents by expiry year
• Presence of drug product or method-of-use patents that can block full label substitution
• Litigation outcomes and settlements that remove remaining injunction leverage

What investors model as durability

• A declining baseline with episodic drag from additional generic entrants.
• A slower decline when:
  • generic substitution is partial (label carve-outs),
  • physician switching frictions persist,
  • supply stability and payer contracts keep net price from collapsing immediately.

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What generic entry risks exist for ISENTRESS, and what launch scenarios could compress sales?

Featured snippet answer: Multiple ANDA entries and label expansions typically compress sales via immediate rebate pressure and faster payer switching; risks are highest around the end of key patent islands.

Launch scenario framework

1. Single first generic: moderate net price compression; share erosion begins in lowest tiers.
2. Multiple generics: sharper rebate pressure; faster channel switching.
3. Label-aligned generics: stronger substitution rates across indications.
4. Formulation-limited generics: slower switch if strengths/dosage forms remain constrained.

Commercial outcomes to track

• TRx decline rates
• Market share by payer segment
• Gross-to-net ratio shifts
• Specialty pharmacy distribution coverage expansion by competitors

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Key timeline: how exclusivity and patent cliffs typically map to revenue

Featured snippet answer: ISENTRESS revenue typically follows a pattern: initial growth, plateau, then step-down after major patent cliffs and sharper declines with multi-generic entry.

Timeline structure for decision-making

• Patent cliff year (drug-substance): first wave of substitution becomes possible.
• Dosage-form/formulation cliff: second wave enables broader generics or preferred substitution formats.
• Method-of-use cliff: final wave removes last payer/physician label friction, accelerating switching.

(A precise ISENTRESS cliff calendar requires Orange Book and litigation record dates; this analysis is limited to dynamics structure.)

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Financial trajectory: what to watch in ISENTRESS revenue over time

Featured snippet answer: Expect continued net sales pressure through pricing erosion, with resilience tied to remaining label breadth, patient stability, and payer contract structure.

Quantitative KPIs that explain “financial trajectory”

• Net sales direction: decline accelerates with generics competition.
• Gross-to-net: rises when rebate intensity increases as competitors enter.
• Prescriber behavior: switch rates and treatment-naïve vs treatment-experienced mix.
• Channel: specialty pharmacy behavior around formulary changes.
• Geography: emerging market tender decisions that shift unit value quickly.

Revenue drivers vs headwinds

• Drivers:
  • persistent INSTI utility in combination therapy,
  • patient stability and physician comfort in established regimens.
• Headwinds:
  • competitive INSTI substitution,
  • commoditization and multi-generic price pressure,
  • formulary steering toward once-daily or fixed-dose combination options.

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Key Takeaways

• ISENTRESS market dynamics are dominated by INSTI class competition, formulary tiering, and pricing compression from generic entry after patent and exclusivity cliffs.
• Financial trajectory typically shows plateau-to-decline behavior consistent with older small-molecule HIV drugs: resilience depends on label breadth, dosing/formulation “islands,” and switching frictions.
• Patent estate strength matters most at the granular level of dosage forms and method-of-use islands, not broad drug-substance protection alone.
• Revenue compression is usually episodic: first wave at key barrier loss, then sharper pressure when multiple generics align with label and dosage formats.

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FAQs

1) How fast do generics reduce ISENTRESS net sales after ANDA approval?

Generic impact typically accelerates once payers switch preferred tiers and label-aligned substitutes expand; the biggest step-down usually follows multi-generic presence rather than a single entrant.

2) Does ISENTRESS lose share in treatment-naïve or mostly in switch patients?

It generally loses share fastest where prescribers can simplify to newer once-daily INSTIs; switch patients remain more stable when regimens are clinically entrenched and prior authorization barriers exist.

3) What role do high-dose ISENTRESS (ISENTRESS HD) formulations play in maintaining revenue?

High-dose and specific dosage-form differentiation can extend periods where not all generics are equivalent on strength and formulation, slowing full payer substitution.

4) Which payer policies most affect ISENTRESS uptake?

Step therapy, prior authorization criteria tied to INSTI preference, and mandatory substitution rules during formulary updates drive most of the displacement effect.

5) How do guideline updates typically influence INSTI market shares?

Guidelines that favor simplified regimens and high-barrier agents increase preference for newer INSTIs, reducing incremental demand for older twice-daily options, except where resistance or patient-specific factors sustain use.

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References

(No citations were provided in the prompt, and no sourced patent/Orange Book/litigation or financial statements are included here.)

DrugChatter Q&A for ISENTRESS

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