United States Patent 6,635,618: Scope, Claims, Expiration, and Glycopeptide Patent Landscape

U.S. Patent No. 6,635,618 covers phosphono-substituted glycopeptide antibiotics, including telavancin and its hydrochloride salt. The strongest commercial claim is claim 21, which targets the specific telavancin molecule. The patent also contains broader genus claims, pharmaceutical-composition claims, manufacturing claims, and bacterial-treatment claims. Its original U.S. patent term expired in January 2021, eliminating the patent as a current U.S. barrier to generic entry, subject to any separately listed continuation, reissue, or later formulation patent.

What drug does U.S. Patent 6,635,618 protect?

The claims identify telavancin by structure rather than by name. Telavancin is a lipoglycopeptide derived from vancomycin. Its key structural modifications are:

A decylaminoethyl lipophilic substituent.
A phosphonomethylaminomethyl group attached to the glycopeptide core.
A hydrochloride salt form used in the marketed product.
A glycopeptide antibiotic pharmacophore derived from vancomycin.

Claim 20 describes the specific compound with:

R3 as hydroxyl.
R5 as N-(phosphonomethyl)-aminomethyl.
R19 as hydrogen.
R20 as -CH2CH2-NH-(CH2)9CH3.

Claim 21 repeats the specific compound definition without the express hydrochloride limitation. Claim 22 narrows the compound to the hydrochloride salt.

This claim architecture is consistent with telavancin, the active ingredient in Vibativ. The FDA approved Vibativ in 2009 for certain complicated skin and skin-structure infections caused by susceptible Gram-positive bacteria and later approved it for hospital-acquired and ventilator-associated bacterial pneumonia under specified conditions.[1]

What are the main claim categories in U.S. Patent 6,635,618?

The 31 claims fall into five functional categories.

Claim category	Claims	Primary scope
Broad phosphono-glycopeptide genus	1	Any glycopeptide bearing one or more phosphono-containing substituents
Structural subgenera	2-4	Phosphono substitution at the carboxy terminus or 1,3-dihydroxyphenyl moiety
Formula I and II compounds	5-22	Detailed Markush structures covering substituted glycopeptide derivatives
Pharmaceutical compositions	23-27	Glycopeptides with carriers, particularly hydroxypropyl-beta-cyclodextrin
Manufacturing and therapeutic methods	28-31	Derivatization processes and treatment of bacterial disease

The claims are arranged from broad chemical concepts to narrower structural embodiments. Claims 20 through 22 provide the clearest protection for telavancin itself.

How broad is claim 1?

Claim 1 is a broad genus claim. It covers:

A glycopeptide substituted with one or more substituents, each comprising one or more phosphono groups.

The claim is not limited to telavancin, vancomycin, a particular attachment site, a specific number of phosphono groups, or a particular antibacterial indication. It also expressly covers pharmaceutically acceptable salts, stereoisomers, and prodrugs.

Its practical scope depends on three elements:

The molecule must qualify as a glycopeptide.
At least one substituent must contain one or more phosphono groups.
The phosphono-containing substituent must be covalently associated with the glycopeptide.

Claim 1 would potentially reach numerous phosphonated derivatives of glycopeptide antibiotics, including derivatives of vancomycin, teicoplanin, ristocetin, and related scaffolds. The claim does not require the derivative to retain antibacterial activity, although utility and enablement considerations would affect enforcement against particular compounds.

The broad wording creates potential validity pressure under written-description and enablement doctrines. A defendant could argue that the disclosure does not support every glycopeptide and every possible phosphono substituent encompassed by the language. The claim's practical strength would therefore depend heavily on the specification's examples, synthetic disclosure, biological data, and prosecution history.

What do claims 2 through 4 protect?

Claims 2 through 4 identify preferred attachment locations.

Claim 2: carboxy-terminus substitution

Claim 2 covers a glycopeptide with a carboxy terminus substituted by a group containing one or two phosphono groups. It is narrower than claim 1 because it specifies both the attachment site and the number of phosphono groups.

Claim 3: 1,3-dihydroxyphenyl substitution

Claim 3 covers a glycopeptide containing a 1,3-dihydroxyphenyl moiety, with phosphono substitution at the 2-position. This limitation is structurally important because the vancomycin-type core contains aromatic residues with defined substitution patterns.

Claim 4: defined linker groups

Claim 4 narrows claim 3 to specified substituents, including:

N-(phosphonomethyl)aminomethyl.
N-(2-hydroxy-2-phosphonoethyl)aminomethyl.
N-carboxymethyl-N-(phosphonomethyl)aminomethyl.
N,N-bis(phosphonomethyl)aminomethyl.
N-(3-phosphonopropyl)aminomethyl.

The N-(phosphonomethyl)aminomethyl group is the relevant limitation for telavancin. These claims are more defensible than claim 1 against an enablement challenge because they identify defined attachment chemistry and preferred molecular embodiments.

What is the scope of the Markush claim in claim 5?

Claim 5 is the central detailed composition-of-matter claim. It covers compounds of formula I in which numerous substituent positions can independently carry hydrogen, alkyl, aryl, heterocyclic, saccharide, amino, sulfur, oxygen, phosphono, and linker-containing groups.

The critical limitation is:

At least one of R3 and R5 must be a substituent comprising one or more phosphono groups.

The claim therefore covers two principal arrangements:

Phosphono substitution at R3.
Phosphono substitution at R5.
Compounds carrying phosphono-containing groups at both positions.

The claim allows substantial variation in:

Sugar substitution.
Aromatic and heteroaromatic groups.
Nitrogen, oxygen, sulfur, and carbon linkages.
Phosphonate-containing linkers.
Lipophilic side chains.
Salt, stereoisomer, and prodrug forms.

Claims 6 through 13 narrow the formula I genus. Claim 13, for example, specifies R5 as -CH2-NH-Ra-P(O)(OH)2, which is close to the phosphonomethylaminomethyl substitution associated with telavancin.

From a freedom-to-operate perspective, claim 5 is most relevant to non-telavancin phosphono-glycopeptides that preserve the claimed formula while changing the sugar, lipid chain, aromatic residues, or phosphono linker.

What do claims 14 through 22 add?

Claims 14 through 22 cover formula II compounds and specific embodiments.

Claim 14 establishes a second compound genus with R19 and R20 substituent definitions. Claims 15 through 18 separately narrow R3 and R5. Claim 19 lists specific lipophilic R20 groups, including:

Long-chain aminoalkyl groups.
Long-chain thioethers.
Sulfoxides.
Sulfonamides.
Biphenyl-containing groups.
Halogenated aromatic groups.
Naphthyl and alkynyl aromatic groups.

These limitations reflect the medicinal-chemistry strategy behind lipoglycopeptide optimization. The hydrophobic R20 group affects membrane interaction, antibacterial potency, pharmacokinetics, and toxicity.

Claims 20 and 21 narrow to the telavancin structure. Claim 22 covers the hydrochloride salt.

Relative strength of claims 20 through 22

Claim	Subject matter	Commercial significance
20	Specific telavancin structure, with pharmaceutically acceptable salts	Direct composition protection
21	Specific telavancin structure	Core molecule claim
22	Telavancin hydrochloride	Salt-form protection

A generic manufacturer making the same active ingredient would face the greatest historical risk under claims 20 and 21. A manufacturer using the hydrochloride form would also have faced claim 22.

Because these are composition claims, they would generally be stronger against an ANDA product than method-of-use claims, assuming validity and enforceability. They do not require proof that the accused product is used for a particular indication.

What formulations are protected by the patent?

Claims 23 through 27 cover pharmaceutical compositions containing a claimed phosphono-glycopeptide.

The most specific formulation limitations are:

A pharmaceutically acceptable carrier.
A therapeutically effective amount of the glycopeptide.
Cyclodextrin.
Hydroxypropyl-beta-cyclodextrin.
Approximately 250 mg to 1,000 mg glycopeptide.
Approximately 250 mg to 10 g hydroxypropyl-beta-cyclodextrin.
A cyclodextrin-to-glycopeptide weight ratio of 1:1 to 10:1.

These claims focus on formulation and solubility technology. Hydroxypropyl-beta-cyclodextrin can improve aqueous handling of hydrophobic glycopeptides and may support parenteral dosage-form development.

The formulation claims are narrower than the composition claims. They would not cover every telavancin product unless the product or manufacturing process met the cyclodextrin and quantity limitations. Conversely, a product containing telavancin but using a different excipient system could avoid claims 24 through 27 while remaining within the molecule claims during the patent term.

What manufacturing methods are claimed?

Claims 28 and 29 cover preparation methods:

Claim 28 covers derivatizing a starting glycopeptide with a carboxy terminus.
Claim 29 covers derivatizing a glycopeptide with an unsubstituted 2-position on the 1,3-dihydroxyphenyl moiety.

These are process claims rather than product claims. They target the chemical route used to install phosphono-containing groups. Their enforceability depends on the actual synthetic steps used by an accused manufacturer.

A generic producer could avoid a process claim by using a materially different route, although the final product could still fall within claims 1, 5, 14, 20, or 21.

What method-of-use claims does the patent contain?

Claims 30 and 31 cover treatment of a mammal with bacterial disease using:

A claimed phosphono-glycopeptide.
A pharmaceutical composition containing the claimed glycopeptide.

These claims are broad in disease scope. They do not limit treatment to a particular pathogen, infection site, dosing schedule, or route of administration.

Their historical value was secondary to the composition claims. In an ANDA dispute, a generic label directed to the patented use could create inducement risk. A section viii statement carving out a patented indication could reduce that risk where the FDA labeling and claim language permit a legally effective carve-out.

When did U.S. Patent 6,635,618 lose exclusivity?

The patent's ordinary U.S. term ran approximately 20 years from its nonprovisional filing date. Public patent records identify U.S. Patent 6,635,618 as an early-2000s application with a grant date of October 21, 2003. Its expected expiration was in January 2021, based on the underlying 2001 filing and January 2000 priority chronology.[2]

Event	Approximate date
Earliest priority filing	January 2000
U.S. application filing	January 2001
Patent grant	October 21, 2003
Expected 20-year expiration	January 2021
FDA approval of telavancin	September 2009
NCE exclusivity expiration	September 2014
Current status of original patent	Expired

The controlling term calculation requires review of the official patent-term adjustment record and any terminal disclaimer. The original patent is no longer a live U.S. composition barrier based on its ordinary term.

What was the FDA and Orange Book status?

Telavancin was approved through an NDA rather than an abbreviated new drug application. The FDA classified telavancin as a new molecular entity and granted five years of new chemical entity exclusivity. That exclusivity ended in 2014, well before the patent's January 2021 expiration.[1]

U.S. Orange Book relevance historically centered on the patents listed for Vibativ, including the telavancin composition patent. Orange Book listing does not determine patent validity. It gives the NDA holder a statutory mechanism to receive notice of an ANDA applicant's Paragraph IV certification and, if suit is filed within the statutory period, potentially obtain a 30-month stay of approval under Hatch-Waxman.[3]

After expiration, U.S. Patent 6,635,618 no longer supports a new 30-month stay or a continuing injunction against commercial manufacture based solely on that patent.

Were there Paragraph IV challenges or patent litigation?

The supplied claims establish the patent's scope but do not establish the existence, timing, or outcome of any Paragraph IV notice, ANDA litigation, settlement, license, or consent judgment.

The relevant legal exposure during the patent term would have included:

Paragraph IV certification against an Orange Book-listed telavancin patent.
Declaratory-judgment litigation by an ANDA applicant.
Infringement litigation based on claims 20 through 22.
Induced-infringement claims based on claims 30 and 31.
Product-by-process or route-based disputes under claims 28 and 29.

No litigation result can be inferred from the patent claims alone. The patent's expiration means that any current generic-entry analysis should focus on later patents, regulatory exclusivity, product-specific labeling, and manufacturing know-how rather than this patent as an independently enforceable right.

How strong is the patent estate?

The estate was strongest against an identical telavancin product and weaker against chemically distant phosphono-glycopeptides.

Dimension	Assessment
Exact telavancin composition	Strong during term
Telavancin hydrochloride	Strong during term, subject to salt-claim validity
Broad phosphono-glycopeptide genus	Broad but more exposed to written-description and enablement attacks
Cyclodextrin formulation	Narrower and easier to design around
Manufacturing route	Dependent on actual process used
Bacterial-treatment claims	Potentially useful, but vulnerable to label carve-outs
Current blocking effect	None from the expired original patent

The patent's commercial value depended on claims 20 through 22, not only on claim 1. The broad genus claims increased coverage around follow-on chemistry, while the narrow claims provided a direct infringement position against the marketed molecule.

How does this patent compare with biosimilar and generic risk?

Telavancin is a small-molecule drug, not a biologic. Biosimilar provisions under the Public Health Service Act do not apply. The relevant pathway is an ANDA under section 505(j) of the Federal Food, Drug, and Cosmetic Act.

Current entry risks are therefore:

Generic substitution and ANDA approval.
Residual regulatory exclusivity, if any later exclusivity applies.
Later formulation or method patents.
Manufacturing complexity associated with glycopeptide fermentation, purification, selective derivatization, and impurity control.
Labeling restrictions for patented indications.

The expired patent does not prevent a generic manufacturer from pursuing telavancin approval. Manufacturing know-how may still affect cost, yield, impurity profiles, and launch timing, but those barriers are separate from patent enforceability.

What licensing deals affect telavancin?

Telavancin development and commercialization involved Theravance and commercial partners, with Astellas historically associated with U.S. commercialization of Vibativ. Cumberland Pharmaceuticals later obtained U.S. rights to Vibativ from Theravance Biopharma.[4]

Those commercial agreements concern product rights and economics. They do not extend the statutory term of U.S. Patent 6,635,618. Any license to the expired patent would have limited current exclusionary value unless it also covers confidential know-how, later patents, data rights, or other contractual obligations.

What revenue exposure was tied to this patent?

The patent principally protected Vibativ revenue during the period before January 2021. Its direct revenue exposure was the U.S. telavancin franchise, including approved hospital and skin-infection indications.

The patent did not protect all revenue generated by the product. Commercial exposure also depended on:

FDA approval and labeling.
Hospital formulary placement.
Safety monitoring and renal-use restrictions.
Competing agents, including vancomycin, linezolid, daptomycin, dalbavancin, and oritavancin.
Later patents and regulatory rights.
Availability of generic or alternative lipoglycopeptide therapy.

Once the patent expired, the principal value shifted from exclusivity to brand recognition, supply reliability, clinical positioning, and manufacturing control.

Key Takeaways

U.S. Patent 6,635,618 is a phosphono-glycopeptide patent associated with telavancin.
Claims 20 through 22 are the most commercially important claims because they cover telavancin and its hydrochloride salt.
Claim 1 is a broad genus claim covering phosphono-substituted glycopeptides generally.
Claims 23 through 27 cover cyclodextrin formulations, particularly hydroxypropyl-beta-cyclodextrin formulations.
Claims 28 and 29 cover selected derivatization routes.
Claims 30 and 31 cover bacterial-disease treatment methods.
The patent's ordinary U.S. term expired in January 2021.
Telavancin's five-year NCE exclusivity expired in 2014.
Telavancin is subject to generic, not biosimilar, competition.
Any current market-entry barrier must come from later patents, regulatory rights, labeling restrictions, or manufacturing know-how.

FAQs

Does U.S. Patent 6,635,618 claim telavancin by name?

No. It claims telavancin by structural definitions, principally in claims 20 through 22.

Does the patent cover telavancin hydrochloride?

Yes. Claim 22 specifically covers the hydrochloride salt of the compound described in claim 20.

Can a generic manufacturer avoid the patent by using a different salt?

The patent has expired, so salt selection is no longer sufficient to avoid an enforceable claim in this patent. During the patent term, a different salt could still have fallen within claims 20 or 21 if those claims covered pharmaceutically acceptable salts.

Does the patent cover vancomycin itself?

No. The claims require a phosphono-containing substituent. Unmodified vancomycin would not satisfy that limitation.

Is telavancin subject to biosimilar competition?

No. Telavancin is a small molecule. A competing product would generally proceed through the generic-drug ANDA pathway rather than the biosimilar pathway.

References

U.S. Food and Drug Administration. (2009). VIBATIV (telavancin hydrochloride) prescribing information. https://www.accessdata.fda.gov
United States Patent and Trademark Office. (2003). U.S. Patent No. 6,635,618, phosphono glycopeptides. https://patents.google.com/patent/US6635618
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations, Orange Book. https://www.fda.gov/drugsatfda
Cumberland Pharmaceuticals Inc. (2018). Annual report and corporate disclosures concerning Vibativ commercialization rights. https://www.cumberlandpharma.com

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	1292612	⤷ Start Trial	C300507	Netherlands	⤷ Start Trial
European Patent Office	1292612	⤷ Start Trial	CA 2011 00033	Denmark	⤷ Start Trial
European Patent Office	1292612	⤷ Start Trial	91908	Luxembourg	⤷ Start Trial
European Patent Office	1292612	⤷ Start Trial	PA2012002	Lithuania	⤷ Start Trial
European Patent Office	1292612	⤷ Start Trial	1190036-2	Sweden	⤷ Start Trial
European Patent Office	1292612	⤷ Start Trial	11C0051	France	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 6,635,618

Summary for Patent: 6,635,618