United States Patent 7,101,576: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 7,101,576, hereafter referred to as the '576 patent, is a significant intellectual property asset related to the pharmaceutical industry. This patent pertains to a nanoparticulate formulation of megestrol acetate, specifically designed for the treatment of anorexia, cachexia, and unexplained weight loss in patients with HIV and AIDS.
Background of the Patent
The '576 patent was granted to Par Pharmaceuticals, Inc. and Alkermes Pharma Ireland, Limited, and it relates to their product Megace ES. This medication is a nanoparticulate formulation of megestrol acetate, which enhances the bioavailability and efficacy of the drug compared to traditional formulations[2][5].
Scope of the Patent
The scope of the '576 patent encompasses several key aspects:
Nanoparticulate Formulation
The patent describes a nanoparticulate composition comprising megestrol acetate and at least one surface stabilizer. This formulation is designed to improve the solubility and stability of megestrol acetate, leading to better absorption and therapeutic outcomes[1].
Therapeutic Indications
The primary therapeutic indications for this formulation include the treatment of anorexia, cachexia, and unexplained weight loss in patients with HIV and AIDS. The nanoparticulate formulation is particularly beneficial in these conditions due to its enhanced bioavailability and ease of administration[2][5].
Surface Stabilizers
The patent specifies the use of various surface stabilizers, such as polyvinylpyrrolidone, to stabilize the nanoparticulate megestrol acetate. These stabilizers prevent the nanoparticles from aggregating and ensure consistent drug delivery[1].
Claims of the Patent
The '576 patent includes multiple claims that define the scope of the invention:
Independent Claims
Claims 1, 4, 7, and 10 are among the independent claims that outline the core aspects of the nanoparticulate formulation, including the composition, method of preparation, and therapeutic uses[2].
Dependent Claims
Dependent claims (e.g., claims 2, 5, 12-17, 19, 21, 24, and 26-31) further specify the details of the formulation, such as the particle size, surface stabilizers, and methods of administration. These claims provide a detailed description of the invention and its various embodiments[2].
Patent Landscape and Litigation
The '576 patent has been a subject of significant litigation, particularly in the context of generic drug manufacturers.
Infringement and Invalidity Challenges
TWi Pharmaceuticals, Inc. (TWi) filed an Abbreviated New Drug Application (ANDA) with the FDA to market a generic version of Megace ES. Par Pharmaceuticals, Inc. and Alkermes Pharma Ireland, Limited alleged that TWi's generic version would infringe the '576 patent. TWi defended by arguing that the patent was invalid due to obviousness, lack of enablement, and failure to cover patentable subject matter[2][5].
Court Rulings
The court ultimately ruled that the '576 patent was invalid as obvious, based on the standard of review that requires clear and convincing evidence to prove invalidity. The court considered factors such as the level of ordinary skill in the art, the scope and content of prior art, differences between the prior art and the claimed subject matter, and secondary considerations of non-obviousness[2][5].
Commercial Impact
Despite the patent's invalidation, Megace ES had a significant commercial impact. Since its launch in 2005, the drug generated over $600 million in net sales. The litigation and subsequent invalidation of the patent allowed generic versions to enter the market, potentially altering the competitive landscape for megestrol acetate formulations[2].
Key Takeaways
- Nanoparticulate Formulation: The '576 patent revolves around a nanoparticulate formulation of megestrol acetate, enhancing its bioavailability and therapeutic efficacy.
- Therapeutic Indications: The primary use is for treating anorexia, cachexia, and unexplained weight loss in HIV and AIDS patients.
- Surface Stabilizers: The use of surface stabilizers like polyvinylpyrrolidone is crucial for maintaining the stability of the nanoparticles.
- Litigation and Invalidity: The patent was invalidated due to obviousness, allowing generic versions to enter the market.
- Commercial Impact: Megace ES generated substantial revenue before the patent's invalidation.
FAQs
What is the main subject of United States Patent 7,101,576?
The main subject is a nanoparticulate formulation of megestrol acetate used to treat anorexia, cachexia, and unexplained weight loss in patients with HIV and AIDS.
What are the therapeutic indications for Megace ES?
The primary therapeutic indications include treating anorexia, cachexia, and unexplained weight loss in patients with HIV and AIDS.
Why was the '576 patent invalidated?
The patent was invalidated due to obviousness, as the court found that the differences between the claimed invention and prior art were not significant enough to be considered non-obvious.
What was the commercial impact of Megace ES?
Since its launch in 2005, Megace ES generated over $600 million in net sales before the patent's invalidation.
Who were the parties involved in the litigation over the '576 patent?
The parties involved were Par Pharmaceuticals, Inc., Alkermes Pharma Ireland, Limited, and TWi Pharmaceuticals, Inc.
Sources
- US7101576B2 - Nanoparticulate megestrol formulations - Google Patents
- IN THE UNITED STATES DISTRICT COURT FOR THE DISTRICT OF MARYLAND PAR PHARMACEUTICALS, INC. and ALKERMES PHARMA IRELAND LTD. v. TWI PHARMACEUTICALS, INC. - USCOURTS-mdd-1_11-cv-02466
- Patent Claims Research Dataset - USPTO
- Search for patents - USPTO
- PAR Pharms., Inc. v. TWI Pharms., Inc. - Casetext
