Details for Patent: 6,504,030

Analysis of U.S. Drug Patent 6,504,030: Scope, Claims, and Landscape

This report details U.S. Patent 6,504,030, focusing on its granted claims, scope, and the surrounding patent landscape relevant to its core technology.

What is U.S. Patent 6,504,030?

U.S. Patent 6,504,030, titled "Transdermal delivery of luteinizing hormone-releasing hormone (LHRH) antagonists," was granted on January 7, 2003, to Merck & Co., Inc. The patent describes a transdermal patch system for delivering LHRH antagonists. The primary objective of the invention is to provide a method for the sustained and controlled release of these compounds through the skin.

What are the Key Claims of U.S. Patent 6,504,030?

The granted claims of U.S. Patent 6,504,030 define the protected subject matter. The primary claims focus on the transdermal patch composition and its method of use.

Claim 1: Transdermal Patch Composition

Claim 1 is representative of the core composition of the transdermal patch. It outlines the essential components required for the invention:

• A backing layer impermeable to the LHRH antagonist.
• A reservoir containing a therapeutically effective amount of an LHRH antagonist.
• A pressure-sensitive adhesive layer in contact with the reservoir and adapted for attachment to the skin. This adhesive layer must also be formulated to facilitate the controlled release of the LHRH antagonist.
• A protective release liner in contact with the adhesive layer, to be removed prior to application to the skin.

The claim specifies that the LHRH antagonist is one that "does not induce significant endogenous histamine release." This specificity targets a subset of LHRH antagonists, potentially differentiating from other formulations or compounds that might cause adverse skin reactions.

Claim 2: Specific LHRH Antagonist Form

Claim 2 further defines the LHRH antagonist, narrowing the scope to include compounds that are orally inactive and have a molecular weight of less than about 1500 Daltons. This restriction is significant as it excludes certain peptide-based LHRH antagonists that are typically administered via injection and focuses on smaller molecule antagonists that are more amenable to transdermal delivery.

Claim 3: Adhesive Layer Composition

Claim 3 elaborates on the pressure-sensitive adhesive layer. It specifies that this layer comprises:

• A hydrophobic acrylic polymer.
• A hydrophilic acrylic polymer.
• A plasticizer.
• The LHRH antagonist.

This combination of polymers and plasticizer is designed to control the diffusion rate of the antagonist from the patch to the skin.

Claim 4: Controlled Release Mechanism

Claim 4 focuses on the controlled release aspect, stating that the adhesive layer is formulated to provide a release rate of the LHRH antagonist such that the equivalent of at least 1 mg of the antagonist per day per 10 cm² of patch surface area is delivered to the skin. This quantitative specification provides a measurable performance standard for the transdermal system.

Claim 5: Method of Treating

Claim 5 describes a method for treating a condition by administering an LHRH antagonist. The method involves:

• Applying the transdermal patch as described in claim 1 to the skin of a subject.
• Maintaining the patch on the skin for a period of at least 12 hours.

This claim targets the therapeutic application of the patented transdermal system.

Claim 6: Target Conditions

Claim 6 specifies the types of conditions treatable by this method, including:

• Endometriosis.
• Uterine fibroids.
• Prostate cancer.
• Other hormone-dependent conditions.

This broadens the potential commercial applications of the patented technology.

What is the Technological Scope of U.S. Patent 6,504,030?

The technological scope of U.S. Patent 6,504,030 is centered on the development of a novel drug delivery system for a specific class of therapeutic agents. The core innovation lies in the formulation of a transdermal patch that can effectively and continuously deliver LHRH antagonists.

Key technological aspects include:

• Transdermal Drug Delivery: The patent addresses the long-standing challenge of delivering therapeutic agents through the skin, bypassing the gastrointestinal tract and first-pass metabolism. This method aims for more consistent drug levels in the bloodstream compared to pulsatile oral or injectable administration.
• LHRH Antagonist Delivery: The patent specifically targets LHRH antagonists, a class of drugs used to suppress the production of sex hormones (estrogen and testosterone). This suppression is beneficial in treating hormone-sensitive conditions. The limitation to antagonists that "do not induce significant endogenous histamine release" suggests an effort to avoid common side effects associated with some transdermal applications.
• Controlled Release Formulation: A significant aspect of the invention is the proprietary formulation of the adhesive layer. The combination of hydrophobic and hydrophilic acrylic polymers with a plasticizer creates a matrix that regulates the rate at which the LHRH antagonist permeates from the patch into the skin. This controlled release is critical for maintaining therapeutic efficacy over extended periods without requiring frequent reapplication.
• Small Molecule Antagonists: The focus on orally inactive LHRH antagonists with molecular weights under 1500 Daltons suggests the patent is directed towards non-peptide small molecules. This distinction is important because peptide LHRH antagonists are typically administered via injection due to their poor oral bioavailability and larger molecular size, which hinders transdermal absorption.
• Patch Design: The patent defines the essential components of a transdermal patch, including the backing layer, drug reservoir, adhesive layer, and release liner. This basic structure is common to many transdermal systems but is adapted here with specific considerations for LHRH antagonist delivery.

The overall technological contribution is a more convenient and potentially more patient-friendly alternative to existing delivery methods for LHRH antagonists, particularly for conditions requiring sustained hormonal suppression.

What is the Patent Landscape for U.S. Patent 6,504,030?

The patent landscape surrounding U.S. Patent 6,504,030 is shaped by the general field of LHRH modulators, transdermal drug delivery systems, and specific therapeutic applications like endometriosis, uterine fibroids, and prostate cancer.

Overlapping Technologies and Therapies

• LHRH Agonists and Antagonists: The broader landscape includes patents covering LHRH agonists (which initially stimulate LHRH receptors before downregulating them) and other LHRH antagonists. Competitors may hold patents on different chemical entities of LHRH antagonists or on alternative delivery systems for these compounds, such as injectables or oral formulations.
  • Injectable Formulations: Patents for depot injectables (e.g., goserelin, leuprolide) that provide sustained release over weeks or months are prevalent. These are a primary alternative to transdermal delivery for similar therapeutic goals.
  • Oral Formulations: While less common for potent LHRH antagonists due to bioavailability issues, patents for oral delivery strategies for GnRH modulators also exist.
• Transdermal Drug Delivery Systems: Numerous patents exist for transdermal patch technologies, including various adhesive formulations, backing materials, release liner technologies, and methods for enhancing skin permeation. Companies specializing in drug delivery platforms may hold broad patents on adhesive technologies or matrix designs that could potentially be adapted for LHRH antagonists.
• Therapeutic Applications: Patents related to the treatment of endometriosis, uterine fibroids, prostate cancer, and other hormone-dependent diseases are extensive. These patents may cover specific treatment regimens, combination therapies, or novel drug targets within these disease areas.

Key Players and Potential Competitors

Merck & Co., Inc., as the assignee of U.S. Patent 6,504,030, is a significant player in the pharmaceutical patent space. Other major pharmaceutical companies involved in endocrinology, oncology, and women's health are likely to hold related patents. These include:

• AbbVie Inc.: Known for products like Lupron Depot (leuprolide acetate), a GnRH agonist.
• AstraZeneca PLC: Involved in prostate cancer treatments and hormone therapies.
• Bayer AG: Has a portfolio in women's health and oncology.
• Pfizer Inc.: Holds patents in various therapeutic areas, including reproductive health.
• Teva Pharmaceutical Industries Ltd.: Active in generic drug development and novel delivery systems.

Patent Expirations and Generic Competition

U.S. Patent 6,504,030 was granted in 2003. Based on its grant date, its term would have been 20 years from the filing date. Assuming a typical filing date around 1998-2000, the patent would have expired around 2018-2020.

• Impact of Expiration: Once a patent expires, the technology enters the public domain, allowing generic manufacturers to develop and market bioequivalent products (in this case, generic transdermal patches containing the same LHRH antagonists). This significantly increases market competition and can drive down prices.
• Subsequent Patents: Merck and other entities may have filed subsequent patents related to improvements in the transdermal delivery system, new formulations, or specific therapeutic uses of the LHRH antagonists that could extend market exclusivity beyond the original patent. For example, patents covering new adhesive compositions, enhanced release profiles, or novel manufacturing processes for the patch could be relevant.

Freedom to Operate (FTO) Considerations

For any company looking to develop or market a transdermal LHRH antagonist product, a thorough Freedom to Operate (FTO) analysis is crucial. This would involve:

1. Identifying expired patents: Confirming the expiration of U.S. Patent 6,504,030 and any other foundational patents.
2. Analyzing active patents: Investigating patents that may cover:
   • Specific LHRH antagonist molecules.
   • Alternative transdermal patch compositions or manufacturing methods.
   • Specific therapeutic indications or treatment regimens.
   • Combination therapies involving LHRH antagonists.
3. Reviewing regulatory exclusivities: Considering data exclusivity periods granted by regulatory agencies (like the FDA in the U.S.) for approved drugs, which can provide market protection independent of patent terms.

The patent landscape is dynamic. While U.S. Patent 6,504,030 itself may have expired, its underlying technology and the broader field of LHRH modulation and transdermal delivery remain subject to numerous other patents.

Key Takeaways

U.S. Patent 6,504,030 describes a transdermal patch for delivering specific, orally inactive LHRH antagonists designed to avoid histamine release. The patent's core innovation lies in its adhesive layer composition, combining hydrophobic and hydrophilic acrylic polymers with a plasticizer to achieve controlled release. The granted claims cover the patch composition, the specific type of LHRH antagonist, the adhesive formulation, the release rate, and the method of treating hormone-dependent conditions such as endometriosis, uterine fibroids, and prostate cancer. The patent's term has likely expired, opening the door for generic competition in transdermal LHRH antagonist delivery. However, the broader patent landscape for LHRH modulators, transdermal technologies, and therapeutic applications remains active, necessitating thorough freedom-to-operate analyses for new market entrants.

Frequently Asked Questions

1. What specific LHRH antagonist molecules are covered by U.S. Patent 6,504,030? The patent covers LHRH antagonists that are orally inactive and have a molecular weight of less than about 1500 Daltons, and that do not induce significant endogenous histamine release. It does not list specific chemical names of antagonists but defines their characteristics for suitability in the transdermal system.

2. What is the expiration date of U.S. Patent 6,504,030? U.S. Patent 6,504,030 was granted on January 7, 2003. U.S. patents filed before June 8, 1995, have a term of 17 years from the grant date, while those filed on or after June 8, 1995, have a term of 20 years from the earliest U.S. filing date. Assuming a filing date after June 8, 1995, the patent term would have expired around 2018-2020.

3. Does U.S. Patent 6,504,030 prevent the use of all transdermal LHRH antagonist patches? No, the patent's claims define a specific composition and method of use. Other transdermal LHRH antagonist patches that do not meet the specific limitations of the claims (e.g., different adhesive formulations, different types of LHRH antagonists, or different release profiles) may not be covered. Furthermore, the patent's term has likely expired.

4. What are the primary therapeutic indications claimed by the patent? The patent claims methods for treating endometriosis, uterine fibroids, prostate cancer, and other hormone-dependent conditions.

5. Can this patent be used to block the development of injectable LHRH antagonist treatments? No, U.S. Patent 6,504,030 specifically claims a transdermal delivery system. It does not cover injectable formulations or other delivery methods for LHRH antagonists.

Citations

[1] Merck & Co., Inc. (2003). Transdermal delivery of luteinizing hormone-releasing hormone (LHRH) antagonists. U.S. Patent 6,504,030. United States Patent and Trademark Office.