United States Patent 4,962,128: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 4,962,128, issued to Pfizer Inc., is a significant patent in the pharmaceutical industry, particularly for the treatment of anxiety-related disorders using sertraline. This patent, which was granted on October 9, 1990, plays a crucial role in understanding the patent landscape surrounding sertraline, a widely used antidepressant.
Background of Sertraline
Sertraline, marketed under the brand name Zoloft, is a selective serotonin reuptake inhibitor (SSRI) approved by the FDA for treating various mood and anxiety disorders, including depression, panic disorder, and obsessive-compulsive disorder[1][4].
Patent Overview
Title and Assignees
The patent is titled "Method of Treating Anxiety-related Disorders Using Sertraline" and is assigned to Pfizer Inc.[5].
Priority Date
The priority date for this patent is November 2, 1989, indicating when the initial application was filed[5].
Claims
Number and Scope
The patent includes 10 claims that define the method of treating anxiety-related disorders using sertraline. These claims are critical in determining the scope of the patent and what is protected under it[2].
Claim Language
The claims are structured to cover the specific methods of using sertraline to treat various anxiety-related disorders. For instance, the patent claims include methods for treating panic disorder, obsessive-compulsive disorder, and other anxiety-related conditions using sertraline[2].
Patent Scope
Independent Claim Length and Count
Research on patent scope suggests that metrics such as independent claim length and count can be used to measure the breadth of a patent. In the case of U.S. Patent 4,962,128, the independent claims are relatively specific, focusing on the therapeutic use of sertraline rather than broad chemical or mechanical inventions. This specificity can indicate a narrower scope, which is often associated with higher patent quality and fewer litigation issues[3].
Breadth of Protection
The patent's scope is limited to the specific methods of treating anxiety-related disorders with sertraline. This narrow focus ensures that the patent does not overly broaden its claims, which could lead to disputes over patent validity and infringement[3].
Patent Landscape
Related Patents
In addition to U.S. Patent 4,962,128, Pfizer holds other patents related to sertraline, such as U.S. Patents 4,818,518 and 5,248,699. These patents cover different aspects of sertraline, including the compound itself and its crystalline form (Form I polymorph)[1].
Orange Book Listings
Pfizer has listed these patents in the Orange Book (Approved Drug Products with Therapeutic Equivalence Evaluations), which is a critical database for tracking patent expirations and exclusivity periods for pharmaceutical products[1].
Exclusivity and Patent Expiration
Exclusivity Periods
The FDA granted a six-month extension on exclusivity for the pediatric population, extending the exclusivity period for Zoloft until June 30, 2006. This means that generic versions of sertraline could not be marketed until after this date[1].
Patent Expiration Dates
The 518 patent, which covers the sertraline compound itself, expired on December 30, 2005. The699 patent, covering the crystalline form of sertraline, expired on September 28, 2010[1].
Infringement and Litigation
Hatch-Waxman Act
Under the Hatch-Waxman Act, the submission of an Abbreviated New Drug Application (ANDA) with a paragraph IV certification, which challenges the validity or non-infringement of a listed patent, is considered an act of infringement. This provision allows for an automatic 30-month stay of FDA approval for the generic drug, unless there is a court decision on the patent's validity or infringement[1].
Court Cases
In cases like Dr. Reddy's Laboratories, Ltd. v. Pfizer Inc., the court has upheld that filing an ANDA with a paragraph IV certification constitutes infringement under the Hatch-Waxman Act. This ruling emphasizes the importance of patent litigation in the pharmaceutical industry[1].
Impact on Generic Competition
The expiration of key patents and the resolution of litigation can significantly impact the entry of generic competitors into the market. For sertraline, the expiration of the 518 patent in 2005 and the699 patent in 2010 paved the way for generic versions to be approved and marketed, increasing competition and reducing prices for consumers[1].
Conclusion
U.S. Patent 4,962,128 is a pivotal patent in the pharmaceutical industry, particularly for the treatment of anxiety-related disorders using sertraline. Understanding its scope, claims, and the broader patent landscape is crucial for both innovator companies and generic manufacturers. The patent's narrow focus on therapeutic methods ensures a clear and defined scope, while the Hatch-Waxman Act's provisions play a significant role in managing the transition from branded to generic drugs.
Key Takeaways
- Patent Scope: The patent covers specific methods of treating anxiety-related disorders using sertraline.
- Claims: The patent includes 10 claims that define these therapeutic methods.
- Patent Landscape: Related patents cover different aspects of sertraline, including its compound and crystalline form.
- Exclusivity and Expiration: FDA exclusivity periods and patent expirations are critical in determining when generic versions can enter the market.
- Infringement and Litigation: The Hatch-Waxman Act's provisions on ANDA filings and paragraph IV certifications are key in patent infringement cases.
FAQs
What is the main subject of U.S. Patent 4,962,128?
The main subject of U.S. Patent 4,962,128 is the method of treating anxiety-related disorders using sertraline.
Who is the assignee of U.S. Patent 4,962,128?
The assignee of U.S. Patent 4,962,128 is Pfizer Inc.
What is the significance of the Hatch-Waxman Act in patent litigation?
The Hatch-Waxman Act is significant because it defines the submission of an ANDA with a paragraph IV certification as an act of infringement, allowing for a 30-month stay of FDA approval for the generic drug.
When did the key patents for sertraline expire?
The 518 patent expired on December 30, 2005, and the699 patent expired on September 28, 2010.
How does the patent landscape affect generic competition?
The patent landscape, including the expiration of key patents and the resolution of litigation, directly affects when generic versions of a drug can enter the market, thereby increasing competition and reducing prices.
Cited Sources
- Dr. Reddy's Laboratories, Ltd. v. Pfizer Inc. - Casetext
- United States Patent (19) 4,962,128 - Google Patents
- Patent Claims and Patent Scope - SSRN
- US6727283B2 - Sertraline oral concentrate - Google Patents
- US-20030133974-A1 - Unified Patents Portal
