United States Patent 7,438,927: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
The United States Patent 7,438,927, titled "Methods of Treatment Using a Gastric Retained Gabapentin Dosage," was issued to Depomed Inc. on October 21, 2008. This patent is crucial in the pharmaceutical industry, particularly for the treatment of neuropathic pain conditions such as post-herpetic neuralgia (PHN). Here, we delve into the scope, claims, and the broader patent landscape surrounding this patent.
Background and Inventors
The patent was filed on October 25, 2002, and granted six years later. The inventors include Bret Berner and others associated with Depomed Inc., a specialty pharmaceutical company based in Menlo Park, California[2][4].
Scope of the Patent
The patent covers methods of treating neuropathic pain using a gastric retained gabapentin dosage form. This dosage form is designed to swell in the stomach, increasing its size to promote gastric retention and ensure the drug is released over an extended period. This mechanism enhances the bioavailability and efficacy of gabapentin, a drug commonly used for treating neuropathic pain conditions[2][5].
Claims of the Patent
The patent includes several claims that define the scope of the invention. Here are some key claims:
- Claim 17: This independent claim is directed to a method of treating neuropathic pain in a mammal by administering a therapeutically effective amount of a daily dosage of gabapentin. The dosage form is designed to swell in the stomach to increase its size and promote gastric retention[1].
- Claims 18, 25, 26, 61, and 62: These claims depend from either claim 17 or another independent claim (claim 33) and specify various aspects of the treatment method, including the dosage regimen and the type of pain being treated[1].
Patent Claims and Their Limitations
The claims in the '927 patent are detailed and specific, ensuring that the invention is well-defined and distinguishable from prior art. For example:
- Dosage Form: The dosage form must be a solid monolithic matrix that swells in an unrestricted manner upon imbibition of water, with specific dimensions and shapes (e.g., oval or parallelogram) to ensure gastric retention[1][2].
- Drug Release: The dosage form must release substantially all of the drug within a specified time frame, typically within ten hours after immersion in gastric fluid[1].
Patent Landscape and Related Patents
The '927 patent is part of a larger portfolio of patents held by Depomed Inc. related to gastric retained gabapentin dosage forms. Other relevant patents include:
- U.S. Patents Nos. 6,635,280, 6,488,962, 7,731,989, 8,192,756, 8,252,332, and 8,333,992: These patents cover various aspects of the dosage form, including its composition, shape, and release characteristics. They collectively protect the intellectual property surrounding Depomed's gabapentin products, such as Gralise[2][4].
Litigation and Enforcement
The '927 patent has been involved in significant litigation, particularly in the case of Depomed, Inc. v. Actavis Elizabeth LLC. In this case, Depomed alleged that Actavis' generic version of gabapentin infringed several of its patents, including the '927 patent. The court found in favor of Depomed, determining that the patents were valid, definite, and infringed by Actavis' product[2].
Impact on the Pharmaceutical Industry
The '927 patent and related patents have significant implications for the pharmaceutical industry, particularly in the development and marketing of generic drugs. The court's decision in Depomed, Inc. v. Actavis Elizabeth LLC highlights the importance of respecting patent rights and the potential consequences of infringement.
Patent Scope and Quality
The scope of the '927 patent is well-defined, which is crucial for maintaining patent quality. Research on patent scope suggests that narrower claims, such as those in the '927 patent, are associated with a higher probability of grant and a shorter examination process. This aligns with the broader discussion on patent quality, where clear and specific claims are seen as more desirable than overly broad or unclear ones[3].
Expiration and Future Implications
The '927 patent expired on February 26, 2024. The expiration of this patent opens up the market for generic versions of gabapentin, potentially increasing competition and reducing costs for patients. However, it also means that Depomed Inc. will no longer have exclusive rights to the specific methods of treatment described in the patent[1].
Key Takeaways
- Specific Claims: The '927 patent includes detailed and specific claims that define the method of treating neuropathic pain using a gastric retained gabapentin dosage form.
- Litigation: The patent has been successfully enforced in court, protecting Depomed's intellectual property against generic infringement.
- Patent Landscape: The patent is part of a broader portfolio of related patents that collectively protect Depomed's gabapentin products.
- Expiration: The patent expired on February 26, 2024, which will impact the market for gabapentin products.
FAQs
Q: What is the main subject of the United States Patent 7,438,927?
A: The main subject is methods of treatment using a gastric retained gabapentin dosage form for treating neuropathic pain.
Q: Who are the inventors of the '927 patent?
A: The inventors include Bret Berner and others associated with Depomed Inc.
Q: What are the key claims of the '927 patent?
A: The key claims include methods of treating neuropathic pain by administering a therapeutically effective amount of gabapentin in a dosage form that swells in the stomach.
Q: Has the '927 patent been involved in any significant litigation?
A: Yes, it was involved in Depomed, Inc. v. Actavis Elizabeth LLC, where the court found in favor of Depomed, determining that the patent was valid and infringed by Actavis.
Q: When did the '927 patent expire?
A: The patent expired on February 26, 2024.
Cited Sources
- USCOURTS-njd-3_12-cv-01358: Depomed Inc. v. Actavis Elizabeth LLC, Case 3:12-cv-01358-MLC-TJB.
- Robins Kaplan LLP: Depomed, Inc. v. Actavis Elizabeth LLC.
- Hoover Institution: Patent Claims and Patent Scope.
- Google Patents: US 8,333,992 B2 - Gastric Retained Gabapentin Dosage.
- Google Patents: US 7,438,927 B2 - Methods of treatment using a gastric retained gabapentin dosage.
