US Patent 7,816,379: Claims, Scope, Expiration, Orange Book Status, and Patent Landscape
US Patent 7,816,379 protects oxazolidinone antibacterial compounds related to tedizolid, tedizolid phosphate and associated prodrug, salt and phosphate forms. Its claims cover three principal subject areas: chemical compounds, manufacturing processes, and antibacterial uses. The patent is assigned to the tedizolid product franchise historically developed by Dong-A Pharmaceutical and commercialized in the United States by Cubist Pharmaceuticals, later acquired by Merck.
The patent’s strongest commercial relevance is its coverage of the active oxazolidinone scaffold and phosphate forms corresponding to Sivextro, the FDA-approved tedizolid phosphate product. The patent is not a biologic patent, so biosimilar rules do not apply. Generic risk would arise through an Abbreviated New Drug Application, including potential Paragraph IV patent challenges.
What drug and chemical series does US 7,816,379 protect?
The patent claims substituted oxazolidinone derivatives containing:
- A chiral oxazolidin-2-one ring;
- A substituted fluorophenyl group;
- A pyridyl-tetrazole substituent;
- A hydroxymethyl, fluoromethyl, methoxymethyl, aminomethyl, amino-acid ester or phosphate substituent;
- R stereochemistry at the oxazolidinone side chain;
- Free hydroxyl, phosphate, phosphonate-like protected phosphate and metal phosphate forms.
The principal commercial compound is tedizolid phosphate, chemically identified as the phosphate prodrug of tedizolid. The claim set also includes related compounds containing either a 1-methyl- or 2-methyl-tetrazole pyridyl group.
Core structural elements
| Element |
Claim scope |
| Antibacterial class |
Oxazolidinone derivatives |
| Aromatic substituent |
Fluorinated phenyl linked to pyridyl-tetrazole |
| Tetrazole position |
1-methyl- or 2-methyl-tetrazole variants |
| Oxazolidinone configuration |
Primarily R stereochemistry |
| Side-chain options |
Hydroxyl, fluoro, alkoxy, amino, amino-acid ester and phosphate |
| Salt forms |
Hydrochloride, trifluoroacetate and other pharmaceutically acceptable salts |
| Phosphate forms |
Mono-phosphate, protected alkyl phosphate and metal salts, including disodium phosphate |
| Therapeutic use |
Treatment of bacterial infections, particularly Gram-positive infections |
The claims are substantially broader than a single marketed salt. Claim 24 covers a Markush genus of oxazolidinone compounds. Claim 32 identifies numerous specific compounds, including the marketed tedizolid-related structures. Claims 45 through 49 add pharmaceutical-composition and antibacterial-treatment coverage.
What are the independent claims in US 7,816,379?
The patent contains four commercially relevant independent claim categories.
Claim 1: Manufacturing route using a tin-mediated intermediate
Claim 1 covers a process that:
- Reacts a halogenated compound of Formula III with a tin compound;
- Produces a C1-4 alkyl-substituted intermediate of Formula IV;
- Couples that intermediate with Formula VI to form Formula V;
- Optionally converts Formula V into Formula I.
This is a process claim directed to construction of the biaryl oxazolidinone framework. It is narrower than the compound claims because infringement requires performance of the recited reaction sequence or its legally equivalent steps.
Claim 3: Conversion of the hydroxyl intermediate
Claim 3 covers conversion of the R2 hydroxyl group in Formula V to one of several substituents in Formula I. The permitted products include:
- Amino derivatives;
- Alkoxy derivatives;
- Fluoro derivatives;
- Alkyl phosphates;
- Monophosphates;
- Metal salts of monophosphates.
This claim reaches the final functionalization step used to generate multiple prodrug and salt forms.
Claim 24: Compound genus
Claim 24 is the broadest central compound claim. It covers an oxazolidinone derivative of Formula I with defined substitution at R1, R1', R2 and R3. The claim encompasses free compounds and pharmaceutically acceptable salts.
The practical importance of claim 24 is that a generic manufacturer could face infringement risk even if it avoids the precise manufacturing route in claims 1 or 3. A product falling within the claimed chemical genus could independently infringe the compound claims.
Claim 45 and claims 46-49: Composition and treatment
Claim 45 covers a pharmaceutical composition containing a compound of claim 24. Claim 46 covers administering the compound to treat a bacterial infection. Claims 47 through 49 narrow the infection and organism categories, including Gram-positive organisms and Staphylococcus, Enterococcus and Streptococcus.
The supplied claim text contains apparent dependency and numbering inconsistencies. Claim 47 refers to claim 45 while reciting a treatment limitation, and claim 48 appears to depend from claim 46 or 47 inconsistently. Those defects would be evaluated against the issued patent’s official claim text and prosecution history, not the transcription alone.
How broad is the chemical scope of the patent?
The compound scope is broad at the genus level but more concentrated at the commercial-product level.
Broad Markush coverage
Claim 24 permits:
- Hydrogen or fluorine at two aryl positions;
- Multiple R2 substituent classes;
- C1-3 or C1-4 alkyl side chains;
- Cyano, ether and ketone substitutions;
- Several amino-acid residues;
- Numerous pharmaceutically acceptable acid salts.
The listed amino-acid substituents include alanine, glycine, proline, isoleucine, leucine, phenylalanine, beta-alanine and valine. This creates coverage for a family of amino-acid ester prodrugs rather than only tedizolid phosphate.
Specific compound coverage
Claim 32 lists compounds 10, 12, 18, 20, 33, 38, 40-50, 59, 61-70, 72 and 73. These include:
- Tedizolid free alcohol;
- Tedizolid phosphate and disodium phosphate;
- Fluoromethyl and methoxymethyl analogues;
- Glycine, alanine, valine, proline and beta-alanine esters;
- Hydrochloride and trifluoroacetate salts;
- 1-methyl-tetrazole and 2-methyl-tetrazole analogues.
This claim structure gives the patent multiple fall-back positions. Even if a broad genus claim were narrowed or invalidated, separately listed compounds and salt forms may remain relevant, subject to written-description, enablement, anticipation and obviousness challenges.
What does the patent protect about tedizolid phosphate?
The patent’s most important product coverage is directed to the hydroxymethyl oxazolidinone scaffold and its phosphate derivatives.
The relevant compound category includes:
- The free hydroxymethyl compound;
- The monophosphate;
- The disodium monophosphate;
- Protected alkyl phosphate intermediates;
- Related pharmaceutically acceptable salts.
Claim 7 specifically recites reaction with phosphorus oxychloride to produce the monophosphate. Claim 8 covers conversion of the monophosphate into a metal salt, including the disodium salt. This is directly relevant to tedizolid phosphate manufacturing and formulation supply chains.
The patent therefore has both product and process relevance:
| Patent component |
Commercial significance |
| Compound claims |
Potentially read directly on tedizolid or tedizolid phosphate |
| Phosphate claims |
Cover active phosphate prodrug and salt forms |
| Process claims |
May constrain selected synthetic routes |
| Composition claims |
Cover finished pharmaceutical compositions |
| Treatment claims |
Cover use against specified bacterial infections |
When does US Patent 7,816,379 lose exclusivity?
The reported patent expiration date is June 16, 2028, based on the patent’s priority and US patent-term calculation reflected in public patent and Orange Book records. The term is materially later than the ordinary 20-year period measured from the earliest claimed priority because the application entered the US patent system through an international filing route and may include patent-term adjustment.
| Event |
Date or status |
| Earliest priority period |
2005 |
| US patent issued |
October 19, 2010 |
| Patent number |
US 7,816,379 B2 |
| Reported expiration |
June 16, 2028 |
| Patent type |
Small-molecule compound, process and use patent |
| FDA product relevance |
Sivextro, tedizolid phosphate |
| Biosimilar pathway |
Not applicable |
| Expected generic pathway |
ANDA, potentially with Paragraph IV certification |
The exact enforceable term should be confirmed against the USPTO patent-term adjustment and terminal-disclaimer records. A patent expiration date does not itself establish freedom to launch because other patents, regulatory exclusivity, pediatric exclusivity or later-issued patents may affect the product.
What is the Orange Book status of US 7,816,379?
US 7,816,379 has been listed in connection with Sivextro, whose active ingredient is tedizolid phosphate. Sivextro was approved by the FDA in 2014 for acute bacterial skin and skin-structure infections caused by designated susceptible Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus in the approved labeling framework (U.S. Food and Drug Administration, 2014).
The Orange Book relevance is product-specific. Listing means the patent is identified by the NDA holder as claiming the drug, its formulation or an approved method of use. It does not mean every claim is necessarily valid or infringed.
Orange Book implications
An ANDA applicant seeking approval for generic tedizolid phosphate would generally need to address listed patents through one of four certifications:
- Paragraph I, where patent information has not been submitted;
- Paragraph II, where the patent has expired;
- Paragraph III, where approval is sought after patent expiration;
- Paragraph IV, where the applicant asserts that the patent is invalid, unenforceable or will not be infringed.
A Paragraph IV certification can trigger patent litigation under the Hatch-Waxman framework. The first substantially complete Paragraph IV filer may also become eligible for 180-day generic exclusivity, subject to statutory forfeiture provisions.
Are there Paragraph IV challenges to US 7,816,379?
The public record identified for this analysis does not establish a reported, resolved Paragraph IV challenge specifically directed to US 7,816,379. The absence of a publicly identified case does not eliminate the possibility of confidential notice, nonpublic ANDA activity or litigation under another patent in the Sivextro portfolio.
The relevant risk question is broader than whether 7,816,379 has been challenged. A generic applicant would likely assess the complete Orange Book patent set, including later patents directed to formulations, crystalline forms, methods of use, pharmaceutical compositions and manufacturing processes.
What other patents affect the tedizolid patent landscape?
US 7,816,379 is one component of the tedizolid estate. Public patent records identify additional US patents and applications associated with tedizolid compounds, formulations and related processes. The portfolio has included patents such as:
- US 7,816,379, directed principally to oxazolidinone compounds, phosphate forms and preparation methods;
- US 8,063,099, associated with additional tedizolid-related subject matter;
- US 8,609,863, associated with later product or process protection;
- US 9,034,867, associated with additional tedizolid patent coverage.
The precise enforceability of each patent depends on claim construction, prosecution history, terminal disclaimers, maintenance-fee status and any litigation or settlement history. A complete launch analysis must treat the portfolio as a layered estate rather than rely on 7,816,379 alone.
Patent-landscape comparison
| Protection layer |
US 7,816,379 position |
Generic relevance |
| Core chemical entity |
Strong, with broad genus and listed compounds |
High |
| Tedizolid phosphate |
Directly relevant |
High |
| Salt forms |
Broad acid and metal-salt language |
Moderate to high |
| Manufacturing process |
Tin-mediated coupling and phosphate conversion |
Route-dependent |
| Formulation |
General composition claim, limited formulation specificity |
Depends on later patents |
| Method of use |
Broad bacterial-treatment claims |
Potentially relevant under Orange Book |
| Biologic exclusivity |
Not applicable |
None |
| Regulatory exclusivity |
Small-molecule NDA framework |
Relevant but separate from patent term |
How strong is the patent estate?
The patent has meaningful breadth, but its strength varies by claim type.
Stronger claim categories
The strongest practical categories are likely:
- Specific compound claims directed to tedizolid and tedizolid phosphate;
- Claims covering the disodium phosphate form;
- Claims covering the defined R stereochemistry;
- Claims directed to listed compounds with the pyridyl-tetrazole and fluorophenyl arrangement.
These claims are easier to compare against a proposed generic product because they focus on identifiable molecular structures.
More vulnerable claim categories
The broader Markush and process claims present more conventional validity issues:
- Anticipation by earlier oxazolidinone disclosures;
- Obviousness based on linezolid and related oxazolidinone chemistry;
- Written-description support for the full combination of substituents;
- Enablement across the breadth of the genus;
- Indefiniteness or interpretation issues arising from inconsistent terminology;
- Non-infringement based on a materially different synthetic route.
The process claims are particularly dependent on the exact route used by a generic manufacturer. A non-infringing alternative synthesis could avoid claims 1 and 3 while still implicating compound, composition or use claims.
What formulation patents protect Sivextro?
The claims supplied for US 7,816,379 do not provide a detailed tablet, capsule, injectable, excipient, particle-size or solid-state formulation claim. Claim 45 recites a pharmaceutical composition comprising a claim 24 compound, but it does not appear to require a narrow excipient combination or specific dosage form.
Accordingly, formulation risk should be analyzed separately from the chemical patent. Potential later-layer protections may concern:
- Oral tablet composition;
- Stability-enhancing excipients;
- Dissolution profile;
- Solid-state or crystalline forms;
- Particle size;
- Manufacturing conditions;
- Specific dosing regimens;
- Intravenous or oral administration.
The absence of a narrow formulation claim in the supplied text does not establish that the marketed product lacks formulation patent protection.
What litigation and settlement issues affect generic entry?
No litigation or settlement agreement is established by the claim text. Generic-entry analysis should distinguish three possible scenarios:
| Scenario |
Likely outcome |
| No ANDA filing before core patent expiry |
Entry generally waits for patent expiration or regulatory resolution |
| Paragraph IV filing with litigation |
Approval may be subject to a 30-month stay and court outcome |
| Paragraph III or post-expiry launch |
Entry may occur after June 2028, subject to other listed patents |
A settlement could provide an authorized-generic arrangement, a licensed entry date, or a covenant not to sue. The supplied information does not identify such an agreement.
Which companies are associated with tedizolid commercialization and licensing?
Tedizolid originated from Dong-A Pharmaceutical. Trius Therapeutics acquired development and commercialization rights in the United States and was later acquired by Cubist Pharmaceuticals. Merck acquired Cubist in 2015 and became the commercial owner of Sivextro in the United States.
The licensing and ownership chain is commercially relevant because patent enforcement rights may have moved through assignments or exclusive licenses. Patent ownership, NDA ownership and marketing rights do not necessarily reside in the same entity.
| Entity |
Role in the product history |
| Dong-A Pharmaceutical |
Originator and early developer |
| Trius Therapeutics |
US development and commercialization partner |
| Cubist Pharmaceuticals |
Acquired Trius and commercialized tedizolid |
| Merck |
Acquired Cubist and commercialized Sivextro |
What generic launch risks exist?
The principal generic risks are:
- Direct infringement of compound claims by tedizolid phosphate;
- Orange Book litigation following a Paragraph IV certification;
- Additional patents not captured by US 7,816,379;
- Regulatory exclusivity or pediatric exclusivity;
- Difficulty designing around the pyridyl-tetrazole oxazolidinone scaffold;
- Manufacturing overlap with the tin-mediated coupling or phosphorus oxychloride phosphorylation routes;
- Potential infringement by salts or prodrug forms that remain within the Markush claims;
- Commercial uncertainty due to the relatively small market for a branded antibiotic.
A generic product that uses a different process may avoid process claims but cannot avoid a valid compound claim merely by changing the manufacturing route. Conversely, a structurally different oxazolidinone may avoid literal compound infringement but face separate validity, doctrine-of-equivalents or regulatory issues.
How does US 7,816,379 compare with linezolid patents?
Tedizolid and linezolid are both oxazolidinone antibacterials, but their patent estates differ.
| Issue |
Tedizolid |
Linezolid |
| Core scaffold |
Fluorinated oxazolidinone with pyridyl-tetrazole group |
Morpholine-acetamide substituted oxazolidinone |
| Commercial product |
Sivextro |
Zyvox |
| Key prodrug |
Tedizolid phosphate |
No directly comparable phosphate prodrug in the marketed product |
| Main patent relevance |
Compound, phosphate, salt, process and use claims |
Core compound and formulation/use layers |
| Generic pathway |
ANDA |
ANDA |
| Biosimilar pathway |
Not applicable |
Not applicable |
| Strategic differentiation |
Once-daily dosing and Gram-positive indication |
Established broad oxazolidinone franchise |
The linezolid estate does not provide a direct substitute for tedizolid patent protection. A competitor cannot avoid tedizolid patents merely by relying on the older linezolid literature if the proposed product remains within the claimed tedizolid structures.
What is the commercial exposure from US 7,816,379?
The patent is commercially important because it supports the principal molecular and prodrug identity of Sivextro. Its revenue exposure is narrower than that of a blockbuster cardiovascular or oncology product because Sivextro addresses a defined antibacterial market and competes with established agents.
Merck’s public financial reporting has not consistently disclosed Sivextro revenue as a separate, material line item. The absence of a standalone revenue figure limits product-specific valuation based solely on public annual-report data. The patent’s commercial value instead derives from:
- Protection of the active pharmaceutical ingredient;
- Protection of the phosphate prodrug;
- Delay of generic competition;
- Support for manufacturing and licensing negotiations;
- Leverage over alternative oxazolidinone products.
Key Takeaways
- US 7,816,379 covers oxazolidinone compounds related to tedizolid and tedizolid phosphate.
- Claims 1 and 3 protect selected manufacturing and phosphate-functionalization routes.
- Claim 24 provides broad compound-genus coverage.
- Claim 32 identifies numerous specific compounds, salts and phosphate derivatives.
- Claims 45 through 49 cover pharmaceutical compositions and antibacterial treatment.
- The reported patent expiration date is June 16, 2028.
- The patent is relevant to Sivextro’s Orange Book patent estate.
- Tedizolid is a small molecule, so biosimilar rules do not apply.
- A generic applicant would likely use the ANDA pathway and could file a Paragraph IV certification.
- Process design-around may avoid process claims but does not avoid valid compound claims.
- Later tedizolid patents may create additional barriers beyond US 7,816,379.
- Dong-A, Trius, Cubist and Merck are the principal companies associated with development, licensing and commercialization.
FAQs
Does US 7,816,379 cover tedizolid phosphate directly?
Yes. The claims cover oxazolidinone compounds bearing phosphate or metal-phosphate substituents, including disodium phosphate forms corresponding to the tedizolid phosphate product class.
Can a generic manufacturer avoid US 7,816,379 by using a different synthesis?
A different synthesis may avoid the process claims, but it would not avoid a valid compound, composition or treatment claim covering the resulting tedizolid phosphate product.
Is tedizolid phosphate protected by a biologic patent?
No. Tedizolid phosphate is a chemically synthesized small molecule regulated through the NDA and ANDA framework, not the biologic license application and biosimilar framework.
What is the most important claim for a generic tedizolid product?
Claim 24 and its dependent claims are central because they cover the compound genus and related salts. The specific compound listings in claim 32 may also be important for a product matching tedizolid or its phosphate forms.
Does patent expiration automatically permit generic launch?
No. Generic launch may remain subject to other unexpired Orange Book patents, regulatory exclusivity, litigation outcomes, settlement terms and any applicable pediatric exclusivity.
References
-
U.S. Patent and Trademark Office. (2010). US Patent No. 7,816,379 B2: Oxazolidinone derivatives. U.S. Department of Commerce.
-
U.S. Food and Drug Administration. (2014). Sivextro (tedizolid phosphate) prescribing information. U.S. Department of Health and Human Services.
-
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. U.S. Department of Health and Human Services.
-
U.S. Food and Drug Administration. (2024). Orange Book: Approved drug products with therapeutic equivalence evaluations, patent and exclusivity information. U.S. Department of Health and Human Services.
-
Merck & Co., Inc. (2015). Annual report and acquisition disclosures relating to Cubist Pharmaceuticals. Merck & Co., Inc.
