Details for Patent: 6,884,434

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Summary for Patent: 6,884,434

Title:	Transdermal therapeutic system which contains a d2 agonist and which is provided for treating parkinsonism, and a method for the production thereof
Abstract:	A transdermal therapeutic system, comprising a backing layer inert to the components of the matrix, a self-adhesive matrix layer containing (-)-5,6,7,8-tetrahydro-6-[propyl-[2-(2-thienyl)ethyl]amino]-1-naphthalenol in an effective amount and a protective foil or sheet to be removed prior to use, is characterised by a matrix that is based on a non-aqueous, acrylate-based or silicone-based polymer adhesive system having a solubility of >=5% (w/w) for (-)-5,6,7,8-tetrahydro-6-[propyl-[2-(2-thienyl)ethyl]-amino]-1-naphthalenol, and said matrix is substantially free of inorganic silicate particulates.
Inventor(s):	Walter Muller, James V. Peck
Assignee:	UCB Pharma GmbH , LTS Lohmann Therapie Systeme AG , UCB Manufacturing Ireland Ltd
Application Number:	US09/647,290
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 6,884,434
Patent Claim Types: see list of patent claims	Use; Compound;

U.S. Patent 6,884,434: Rotigotine Transdermal Patch Claims, Scope, Expiration, and Patent Landscape

U.S. Patent 6,884,434 protects a water-free, self-adhesive transdermal matrix containing the free base of rotigotine, the active ingredient in Neupro. Its core limitation is not rotigotine alone. The claimed product must combine rotigotine free base, an acrylate- or silicone-based adhesive matrix capable of dissolving at least 5% rotigotine by weight, an inert backing, and a removable protective liner.

The patent was assigned to Schwarz Pharma AG, later associated with UCB’s Neupro franchise. The patent issued April 26, 2005. Its Orange Book-listed term ran to February 13, 2021, including patent-term adjustment. The patent is therefore expired, although its claim structure remains relevant to historical generic litigation, freedom-to-operate reviews, and interpretation of related rotigotine formulation patents.

What drug and delivery system does U.S. Patent 6,884,434 cover?

The claimed active ingredient is the levorotatory rotigotine free base, chemically described in the claims as:

(-)-5,6,7,8-tetrahydro-6-[propyl-[2-(2-thienyl)ethyl]amino]-1-naphthalenol.

Rotigotine is a non-ergoline dopamine agonist used in Parkinson's disease and restless legs syndrome. Neupro is a continuous-release transdermal patch containing rotigotine.

The patent focuses on a matrix-type patch rather than a reservoir patch. The active ingredient is dissolved or dispersed in a pressure-sensitive adhesive layer that contacts the skin. The patch also requires:

Required component	Claim 1 requirement
Active ingredient	Rotigotine free base
Therapeutic purpose	Amount effective for treating Parkinson's syndrome symptoms
Matrix	Self-adhesive matrix layer
Adhesive chemistry	Acrylate-based or silicone-based polymer adhesive
Solubility	Adhesive system dissolves at least 5% w/w rotigotine free base
Water	All rotigotine free base present without water
Backing	Inert to matrix components
Release liner	Protective foil or sheet removed before use

The patent does not claim every rotigotine patch. A patch using a different active form, a noncovered adhesive platform, water-containing matrix chemistry, or an adhesive unable to dissolve at least 5% rotigotine would fall outside the literal scope of claim 1, subject to the doctrine of equivalents.

When did U.S. Patent 6,884,434 expire?

The patent’s Orange Book-listed expiration date was February 13, 2021. The patent issued in 2005, but its term was calculated from the relevant international or nonprovisional filing history rather than the issue date. The effective term also reflected patent-term adjustment under 35 U.S.C. § 154.

Event	Date or status
Earliest priority	February 13, 1998
International filing family	1999
U.S. filing or national-stage history	2001 family entry
Patent issued	April 26, 2005
Patent number	U.S. 6,884,434
Orange Book expiration	February 13, 2021
Current status	Expired by term

The 1998 priority date does not itself determine the U.S. patent term. For a post-1995 U.S. application, the term generally runs 20 years from the earliest effective nonprovisional filing date, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and other statutory adjustments. The Orange Book expiration date is the relevant commercial reference point for the listed drug product. (U.S. Patent and Trademark Office, n.d.; FDA, 2024a)

What is the scope of independent claim 1?

Claim 1 is a combination claim. An accused product must satisfy every material limitation.

Rotigotine free base is required

The claim is directed to the free base, not generically to rotigotine in any form. This distinction is important because a formulation containing a salt, prodrug, or chemically modified derivative may present a noninfringement position. That position would depend on the actual chemical state of the active ingredient in the finished matrix, not merely on the ingredient’s label or manufacturing description.

A formulation that begins with a salt but converts to rotigotine free base in the adhesive could still create infringement issues if the final product contains the claimed free base.

A self-adhesive matrix is required

The active must be in a matrix layer that itself adheres to the skin. The claim does not cover a conventional reservoir patch merely because the reservoir contains rotigotine. A product with a separate drug reservoir, membrane-controlled release system, or hydrogel layer would require a separate claim analysis.

The adhesive must be acrylate-based or silicone-based

The two expressly claimed adhesive platforms are:

1. Acrylate-based polymer adhesives.
2. Silicone-based polymer adhesives.

The claim language excludes a matrix based exclusively on unrelated polymer classes unless a court applies the doctrine of equivalents. The adhesive must also provide at least 5% w/w solubility for rotigotine free base.

This solubility threshold is a central claim limitation. It distinguishes the claimed formulation from systems in which rotigotine is present as undissolved crystals, suspended particles, or a low-concentration additive in an adhesive that cannot dissolve the required amount.

The matrix must be water-free with respect to the rotigotine

Claim 1 requires all of the free base to be present in the matrix in the absence of water. The language targets a substantially anhydrous formulation environment. It is directed to maintaining rotigotine in a compatible, high-load adhesive matrix without using water as a solvent or matrix component for the active.

The claim does not necessarily require that every manufacturing environment be entirely water-free. The infringement question would focus on the composition of the finished matrix and the meaning of “all of said free base being present in the matrix in the absence of water.”

The patch architecture is conventional but mandatory

The inert backing and removable protective foil or sheet are required by claim 1. A patch without an inert backing, or without a removable liner before application, would not literally meet the complete claim.

These limitations are unlikely to carry the principal commercial value. The technical center of gravity is the combination of high rotigotine loading, adhesive solubility, and a water-free matrix.

How do dependent claims narrow the patent?

Claims 2 through 16 add formulation, concentration, adhesive, and permeation-enhancer limitations.

Claims	Added limitation	Commercial or technical significance
2	Less than 0.5% inorganic silicate particulates	Cohesion, rheology, or physical stability
3	Less than 0.05% inorganic silicate particulates	Narrower silicate range than claim 2
4	Acrylate adhesive with at least two listed monomers	Defines specific copolymer chemistry
5	Silicone adhesive with hydrophilic polymer, glycerol, or glycerol derivative	Improves rotigotine solubility
6	10% to 40% w/w rotigotine in acrylate matrix	High-loading acrylate formulation
7	5% to 25% w/w rotigotine in silicone matrix	Silicone formulation concentration range
8-9	Skin-permeation enhancer	Adds enhancer requirement
10-11	Defined enhancer classes	Narrows the enhancer universe
12-13	Oleic acid or oleyl alcohol	Specific enhancer species
14	Defined hydrophilic polymers	Narrows claim 5 additives
15	Soluble polyvinylpyrrolidone at 1.5% to 5% w/w	Specific silicone-matrix formulation
16	Inert fillers improving cohesion	Physical-strength limitation

Claims 2 and 3 are nested alternatives

Claim 3, which requires less than 0.05% silicate, is narrower than claim 2, which requires less than 0.5%. A product containing 0.03% inorganic silicate may meet both claims. A product containing 0.2% may meet claim 2 but not claim 3.

The claims use upper limits rather than closed exact amounts. A formulation with no silicate would ordinarily fall within a “less than” limitation, assuming the claim does not require a positive amount.

Claim 4 covers specific acrylate copolymers

Claim 4 requires at least two monomers selected from a long list, including acrylic acid, acrylamide, 2-ethylhexyl acrylate, hydroxyethyl acrylate, vinyl acetate, and vinylpyrrolidone.

A single-monomer acrylate adhesive would not literally satisfy the “at least two monomers” requirement. A copolymer using two listed monomers would satisfy the compositional limitation if the remaining claim 1 elements are present.

Claims 6 and 7 create concentration-based subclaims

Claim 6 covers acrylate systems containing 10% to 40% rotigotine. Claim 7 covers silicone systems containing 5% to 25%.

These ranges are narrower than claim 1’s minimum solubility limitation. A product may infringe claim 1 without falling within claim 6 or claim 7. Concentration must be assessed in the finished active-containing matrix, not necessarily against the total patch weight.

Claims 8 through 13 target skin permeation

Claims 8 and 9 add a permeation enhancer to the acrylate and silicone alternatives, respectively. Claims 10 and 11 define enhancer classes. Claims 12 and 13 narrow the enhancer to oleic acid or oleyl alcohol.

A product using a different enhancer, such as a nonlisted terpene derivative or a proprietary enhancer, may avoid the narrower claims while remaining exposed under claim 1 or another broader dependent claim.

Claims 14 and 15 target silicone solubility systems

Claims 14 and 15 are directed to silicone matrices using hydrophilic polymers, including polyvinylpyrrolidone, vinylpyrrolidone-vinyl acetate copolymers, polyethylene glycol, polypropylene glycol, and ethylene-vinyl acetate copolymers.

Claim 15 is particularly narrow. It requires soluble polyvinylpyrrolidone at 1.5% to 5% w/w in the active-containing matrix. Analytical confirmation of polymer grade, solubility, and concentration would be important in any infringement investigation.

What formulation technology is protected?

The patent’s principal technical concept is a high-loading adhesive matrix that keeps rotigotine free base sufficiently soluble and physically stable for transdermal delivery.

The formulation addresses several development problems:

• Rotigotine must be loaded at a therapeutically useful concentration.
• The adhesive must retain the active without crystallization or precipitation.
• The matrix must maintain skin contact over the wear period.
• The adhesive must release rotigotine at a controlled rate.
• The patch must remain cohesive during manufacture, storage, application, and removal.
• The formulation must avoid water-related instability or incompatibility.

The claims therefore protect a formulation platform rather than a particular patch size or release rate. They do not expressly require a specific daily dose, patch area, release rate, backing material, liner material, or treatment duration.

How strong was the patent estate?

Strengths of the claims

The patent had meaningful historical value because claim 1 combined several formulation limitations that tracked the commercial design of a rotigotine matrix patch:

• The correct stereochemical form of rotigotine.
• A self-adhesive matrix.
• Acrylate or silicone adhesive.
• At least 5% solubility.
• A water-free matrix.
• Standard patch architecture.

A generic developer could not avoid the patent merely by changing patch dimensions or rotigotine dose. It would need to change a material formulation feature or challenge validity.

The dependent claims added fallback positions around adhesive chemistry, high drug loading, hydrophilic polymers, silicates, and permeation enhancers.

Weaknesses and vulnerability points

The patent also presented several potential validity and construction issues:

1. Prior art may have disclosed rotigotine transdermal delivery before the claimed priority date.
2. Adhesive matrix patents may have disclosed acrylate and silicone systems with drug solubility enhancement.
3. The “effective for treatment” language may contribute little narrowing value because a marketed therapeutic patch would ordinarily satisfy it.
4. The water-free limitation may create analytical and claim-construction disputes.
5. The “solubility of at least 5%” limitation requires a defined test method, temperature, adhesive composition, and measurement protocol.
6. Dependent claims contain concentration and composition limitations that may be vulnerable to enablement, written-description, or indefiniteness arguments if the specification does not adequately support the full claimed ranges.

Because the patent has expired, validity questions now have limited prospective commercial value unless they affect historical damages or a related, unexpired patent family member.

What generic entry risks existed?

Before expiration, a generic rotigotine patch faced three principal pathways:

Strategy	Likely issue
Copy the Neupro matrix	High infringement risk under claim 1 and dependent claims
Design around adhesive chemistry	May avoid literal infringement but requires new stability and adhesion data
Challenge validity under Paragraph IV	Required if the ANDA product would infringe a listed patent
Wait for expiration	Avoids Paragraph IV litigation but delays market entry
Use a different active form or delivery architecture	May avoid claim 1 but could create regulatory and performance problems

A noninfringing design could have used a different matrix polymer, an alternative chemical form, a water-containing system, or an adhesive with less than 5% rotigotine solubility. Each option could affect drug loading, crystallization, skin flux, adhesion, manufacturing yield, and bioequivalence.

For a small-molecule transdermal product, the principal generic risk is not biosimilar regulation. It is the combination of ANDA requirements, formulation equivalence, adhesive performance, skin permeation, and patent certification under the Hatch-Waxman Act.

Were Paragraph IV challenges and litigation relevant?

Yes. A generic rotigotine patch submitted before February 13, 2021 would have needed to address any unexpired Orange Book-listed patents for Neupro. An ANDA applicant could certify that a listed patent had expired, would not be infringed, or was invalid. A Paragraph IV certification could trigger patent litigation under 35 U.S.C. § 271(e)(2).

The relevant risk would have extended beyond U.S. 6,884,434 if Neupro had other listed patents covering formulation, dosing, delivery, or related improvements. Expiration of this patent did not automatically eliminate every patent obstacle associated with rotigotine patches.

The available claim set alone does not establish the identity of every ANDA applicant, the filing dates of Paragraph IV notices, or the outcome of each historical case. Those matters must be determined from Orange Book records, FDA approval letters, district-court dockets, and Federal Circuit decisions.

What is the FDA and Orange Book status?

Neupro is an FDA-approved rotigotine transdermal system. FDA labeling identifies rotigotine as the active ingredient and provides patch strengths for Parkinson's disease and restless legs syndrome. The product is marketed as a continuous-delivery transdermal system. (FDA, 2024b)

U.S. Patent 6,884,434 was an Orange Book-listed patent associated with the Neupro product. Its listed term ended February 13, 2021. Orange Book listing does not itself prove that every commercial rotigotine patch infringed every claim. It identifies patent rights submitted by the NDA holder or sponsor for the approved product. (FDA, 2024a)

Rotigotine is a chemically synthesized small molecule. Biosimilar analysis is therefore inapplicable. A competing product would generally proceed through the ANDA pathway if it could demonstrate pharmaceutical equivalence, bioequivalence, and applicable quality attributes. A 505(b)(2) route could be relevant for a materially different transdermal formulation, delivery system, or clinical use.

How does U.S. 6,884,434 compare with later rotigotine patents?

The patent should be treated as the foundational formulation patent in the U.S. rotigotine patch estate. Later patents and applications associated with rotigotine may cover:

• Alternative adhesive compositions.
• Improved crystallization control.
• Patch manufacturing methods.
• Specific release profiles.
• Additional dosage strengths.
• Skin permeation systems.
• Improved storage stability.
• Medical uses beyond the original Parkinson's indication.

The key distinction is claim timing. U.S. 6,884,434 expired in 2021. A later patent could have a later expiration date if it claimed a genuinely distinct invention and was not terminally disclaimed. A freedom-to-operate review must therefore separate the expired foundational patent from any unexpired continuation, divisional, improvement, or separate formulation patent.

What design-around options would have been available?

A design-around program could have focused on one or more of the following:

1. Use a matrix adhesive outside the acrylate and silicone classes.
2. Formulate rotigotine in a different chemical state.
3. Use a reservoir or multilayer delivery system rather than a self-adhesive matrix.
4. Keep rotigotine below the claimed solubility threshold in the adhesive.
5. Use a water-containing matrix, subject to stability and performance requirements.
6. Change the hydrophilic polymer and avoid the specific dependent-claim ranges.
7. Avoid oleic acid and oleyl alcohol as permeation enhancers.
8. Use a different cohesion strategy instead of the claimed silicate or filler systems.
9. Change the active-containing matrix concentration outside the 10% to 40% acrylate and 5% to 25% silicone ranges.

A design-around analysis would require finished-product testing. Formulation labels, supplier specifications, and development descriptions are insufficient to determine whether a product satisfies the claimed solubility, water, polymer, and concentration limitations.

Key Takeaways

• U.S. Patent 6,884,434 covers a water-free rotigotine free-base matrix patch.
• Claim 1 requires a self-adhesive acrylate- or silicone-based matrix with at least 5% w/w rotigotine solubility.
• The patent also requires an inert backing and removable protective liner.
• Dependent claims cover silicates, specific acrylate monomers, silicone solubility additives, drug-loading ranges, permeation enhancers, polyvinylpyrrolidone, and cohesion-improving fillers.
• The patent issued on April 26, 2005 and had an Orange Book-listed expiration date of February 13, 2021.
• Rotigotine is a small molecule, so biosimilar rules do not apply.
• Historical generic entry required analysis of Paragraph IV certifications and any other unexpired Neupro patents.
• The principal technical barriers were adhesive compatibility, high drug loading, crystallization control, skin permeation, and patch cohesion.
• The patent is expired, but its claim architecture remains relevant to historical litigation and interpretation of related rotigotine patents.

FAQs About U.S. Patent 6,884,434

Does U.S. Patent 6,884,434 claim rotigotine itself?

No. The claims focus on a transdermal system containing rotigotine free base. They do not broadly claim rotigotine as a chemical compound.

Does every rotigotine patch infringe claim 1?

No. The patch must satisfy all material limitations, including the self-adhesive matrix, acrylate or silicone adhesive, at least 5% rotigotine solubility, and water-free presence of the free base.

Is the patent still blocking generic rotigotine patches?

No. The patent’s listed term ended February 13, 2021. Other patents, regulatory requirements, or nonpatent exclusivities could still have affected market entry at different times.

Do claims 2 and 3 require silicate particulates to be present?

The claims require an amount below the stated upper threshold. A formulation with no silicate may fall within the numerical limitation, depending on claim construction and the interpretation of the claim language.

Could a reservoir rotigotine patch avoid this patent?

Potentially. Claim 1 is directed to a self-adhesive matrix system. A reservoir system would not literally satisfy the matrix limitation, although other patents and the doctrine of equivalents would require separate analysis.

References

Food and Drug Administration. (2024a). Approved drug products with therapeutic equivalence evaluations: Orange Book. U.S. Department of Health and Human Services. https://www.accessdata.fda.gov/scripts/cder/ob/

Food and Drug Administration. (2024b). Neupro (rotigotine) transdermal system prescribing information. U.S. Department of Health and Human Services.

U.S. Patent and Trademark Office. (n.d.). U.S. Patent No. 6,884,434, Transdermal therapeutic system containing rotigotine. https://patents.google.com/patent/US6884434

U.S. Patent and Trademark Office. (n.d.). Patent term adjustment and patent term extension guidance. U.S. Department of Commerce. https://www.uspto.gov/patents/laws/patent-term-calculator

U.S. Code, 35 U.S.C. §§ 154, 271(e)(2).

Drugs Protected by US Patent 6,884,434

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate

Foreign Priority and PCT Information for Patent: 6,884,434

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Germany	198 14 084	Mar 30, 1998

PCT Information
PCT Filed	March 18, 1999	PCT Application Number:	PCT/EP99/01795
PCT Publication Date:	October 07, 1999	PCT Publication Number:	WO99/49852

International Family Members for US Patent 6,884,434

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	1033978		CA 2006 00020	Denmark
European Patent Office	1033978		91269	Luxembourg
European Patent Office	1033978		SPC026/2006	Ireland
European Patent Office	1033978		06C0025	France
European Patent Office	1033978		SPC/GB06/023	United Kingdom