United States Patent 7,816,383: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 7,816,383, assigned to Genentech, Inc., is a pivotal patent in the context of treating idiopathic pulmonary fibrosis (IPF) with the drug pirfenidone. This patent, along with others, has been at the center of significant litigation involving generic drug manufacturers. Here, we delve into the scope, claims, and the broader patent landscape surrounding this patent.
Background on Pirfenidone and IPF
Pirfenidone is a medication approved for the treatment of idiopathic pulmonary fibrosis (IPF), a chronic and ultimately fatal disease characterized by a progressive decline in lung function. The drug was first studied in the 1970s and gained FDA approval in the United States in 2014[2].
Patent Overview
Patent Number and Issue Date
The United States Patent 7,816,383 was issued on October 19, 2010. This patent is part of a series of patents related to the use and administration of pirfenidone.
Claims
The patent claims involve specific methods of administering pirfenidone, particularly in the context of drug-drug interactions and liver function tests.
Drug-Drug Interaction (DDI) Claims
The DDI claims focus on methods for administering pirfenidone to patients who are also taking other medications, such as fluvoxamine. For example:
- Claim 6 of the ’383 patent describes a method where fluvoxamine is discontinued before administering pirfenidone to avoid adverse drug interactions[4].
- Claim 3 of the ’002 patent (related to the same family) involves administering pirfenidone and fluvoxamine concurrently, with specific dosage adjustments to avoid interactions[4].
Liver Function Test (LFT) Claims
The LFT claims pertain to adjusting the dosage of pirfenidone based on liver function test results to manage side effects. These claims are centered around standard medical practices for monitoring and adjusting drug dosages in response to liver-associated side effects[2].
Litigation and Legal Challenges
Hatch-Waxman Act and ANDA Proceedings
The Hatch-Waxman Act created the Abbreviated New Drug Application (ANDA) process, allowing generic manufacturers to reference the safety and efficacy data of brand drugs, thereby reducing the need for costly clinical trials. However, this process also invites patent litigation when generic manufacturers challenge the validity of brand patents[2].
Genentech, Inc. v. Sandoz Inc.
In this case, Sandoz submitted ANDAs to market a generic version of pirfenidone, prompting Genentech to file a Hatch-Waxman suit alleging infringement of the LFT and DDI patents. The District Court found the LFT claims unpatentable for obviousness and insufficient evidence to support induced infringement for the DDI claims[2].
Federal Circuit Appeal
On appeal, the Federal Circuit affirmed the District Court's decision, stating that the LFT claims were obvious in light of prior art, including a 2005 clinical trial publication and the PIRESPA label. The court also emphasized that past conduct is relevant in determining future infringement, but in this case, there was insufficient evidence to prove that physicians would induce infringement by following the proposed generic label[2][4].
Patent Landscape
Related Patents
The patent landscape surrounding pirfenidone includes several other patents related to its use and administration. These patents cover various aspects such as dosage regimens, drug interactions, and monitoring protocols. For example:
- U.S. Patent 7,635,707 and U.S. Patent 8,592,462 also pertain to methods of administering pirfenidone, focusing on different aspects of its use[2].
Expiration Dates
The patents related to pirfenidone have varying expiration dates, with some set to expire in the late 2020s and others extending into the early 2030s. For instance, U.S. Patent 7,816,383 is estimated to expire on January 8, 2030[1].
Impact on Generic Competition
The litigation surrounding these patents has significant implications for generic competition. The 180-day exclusivity period granted to the first generic manufacturer that successfully challenges a brand patent can delay market entry for other generics. However, the invalidation of key patents, as seen in the Genentech v. Sandoz case, can expedite the availability of generic versions, reducing costs for patients and increasing market competition[2].
Key Takeaways
- Patent Claims: The patent involves specific methods for administering pirfenidone, including DDI and LFT claims.
- Litigation: The patent was challenged by Sandoz under the Hatch-Waxman Act, with the Federal Circuit affirming the invalidity of the LFT claims and insufficient evidence for induced infringement of the DDI claims.
- Patent Landscape: The patent is part of a broader landscape of patents related to pirfenidone, with varying expiration dates.
- Generic Competition: The outcome of the litigation affects the timing and availability of generic versions of pirfenidone.
FAQs
What is the primary use of pirfenidone?
Pirfenidone is primarily used for the treatment of idiopathic pulmonary fibrosis (IPF), a chronic and fatal lung disease.
What are the key claims of U.S. Patent 7,816,383?
The key claims involve methods for administering pirfenidone, particularly in the context of drug-drug interactions (DDI) and liver function tests (LFT).
Why was Genentech, Inc. v. Sandoz Inc. significant?
This case was significant because it clarified that past conduct is relevant in determining future infringement in ANDA proceedings and resulted in the invalidation of certain LFT claims, affecting the patent landscape for pirfenidone.
How does the Hatch-Waxman Act impact generic drug competition?
The Hatch-Waxman Act incentivizes generic competition by allowing generic manufacturers to reference brand drug safety and efficacy data and challenge brand patent validity, potentially leading to earlier market entry for generics.
What is the estimated expiration date of U.S. Patent 7,816,383?
The estimated expiration date of U.S. Patent 7,816,383 is January 8, 2030.
Sources
- DrugBank: Pirfenidone: Uses, Interactions, Mechanism of Action.
- PCK IP: Past Conduct Deemed Relevant to Infringement in ANDA Proceedings.
- Seyfarth Shaw LLP: The BioLoquitur Bulletin.
- CAFC: GENENTECH, INC. v. SANDOZ INC.
- RPX Insight: 1 IN THE UNITED STATES DISTRICT COURT FOR ...
