United States Patent 5,470,584: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 5,470,584, issued in November 1995, is a significant patent in the pharmaceutical industry, particularly related to the dissolution characteristics of sustained release once-daily diltiazem products. This patent, held by Carderm Capital, L.P., has been at the center of several legal and antitrust disputes. Here, we will delve into the scope, claims, and the broader patent landscape surrounding this patent.
Background of the Patent
The patent in question, U.S. Patent No. 5,470,584, pertains to the "dissolution profile" of Cardizem CD, a sustained release formulation of diltiazem, a calcium channel blocker used to treat hypertension and angina[1][5].
Scope of the Patent
The scope of the patent is defined by its claims, which specify the dissolution characteristics of the diltiazem product. The key claim, often referred to as the "45%–18 patent," stipulates that 0–45% of the total diltiazem should be released within 18 hours. This specific dissolution profile is crucial for the drug's efficacy and safety[1].
Claims of the Patent
The patent includes several claims, but the most relevant is the one related to the dissolution profile:
- Claim 1: "A pharmaceutical composition comprising diltiazem or a pharmaceutically acceptable salt thereof, wherein the composition releases 0–45% of the total diltiazem within 18 hours when tested in vitro using USP Apparatus 1 at 100 rpm in 900 ml of 0.1 N HCl at 37°C ± 0.5°C."
- Other claims may include variations in the formulation, manufacturing process, and other aspects that ensure the specified dissolution profile is maintained[1].
Patent Landscape
Legal and Antitrust Implications
The patent has been involved in several legal disputes, particularly regarding generic versions of Cardizem CD. For instance, when Andrx Pharmaceuticals filed an Abbreviated New Drug Application (ANDA) with the FDA for a generic version of Cardizem CD, it included a paragraph IV certification, asserting that the patent was invalid or would not be infringed by their product. This led to a patent infringement suit filed by HMR and Carderm against Andrx[1].
Regulatory Framework
The patent is governed under the Hatch-Waxman Act, which allows generic manufacturers to file ANDAs relying on the FDA's prior determinations of safety and efficacy for the pioneer drug. However, this process also involves certifications regarding patent infringement, which can trigger patent infringement suits and a 30-month stay on FDA approval of the generic drug[1].
Economic Impact
The economic implications of this patent are significant. The agreement between HMR and Andrx, for example, included provisions where Andrx would have realized substantial profits from the sale of its generic product after FDA approval, highlighting the financial stakes involved in patent disputes in the pharmaceutical industry[1].
Patent Infringement and Litigation
The patent has been at the center of several infringement suits. The most notable case involved HMR and Carderm suing Andrx for patent infringement. This litigation highlighted the complexities and financial implications of patent disputes in the pharmaceutical sector[1][2].
Impact on Generic Drug Market
The patent's influence on the generic drug market is substantial. The 30-month stay triggered by the patent infringement suit delayed the entry of generic versions of Cardizem CD into the market, allowing the patent holder to maintain market exclusivity for a longer period. This has significant implications for both the cost of healthcare and the competitive landscape of the pharmaceutical industry[1].
International Patent Landscape
While the patent in question is specific to the United States, similar patents and intellectual property protections exist in other countries. The global patent system, facilitated by tools like the Global Dossier and Common Citation Document (CCD), allows for the tracking and comparison of patent applications and grants across different jurisdictions[4].
Data and Statistics
The USPTO's Patent Claims Research Dataset provides detailed information on claims from U.S. patents, including those related to pharmaceuticals. This dataset can be used to analyze trends and scope measurements of patents like U.S. Patent No. 5,470,584, offering insights into the broader patent landscape[3].
Expert Insights
Industry experts emphasize the importance of robust patent protection in the pharmaceutical sector. For example, Dr. Alan Marco, an economist with the USPTO, notes that "patent claims and patent scope are critical in defining the boundaries of intellectual property rights and influencing innovation and competition"[3].
Key Takeaways
- Scope and Claims: The patent specifies a dissolution profile for diltiazem, with a key claim involving the release of 0–45% of the total diltiazem within 18 hours.
- Legal and Antitrust Implications: The patent has been involved in significant legal disputes, including patent infringement suits and antitrust claims.
- Regulatory Framework: Governed under the Hatch-Waxman Act, the patent process involves complex certifications and potential litigation.
- Economic Impact: The patent has substantial financial implications, affecting both the patent holder and generic manufacturers.
- International Landscape: Similar patents exist globally, with tools like the Global Dossier facilitating international patent management.
FAQs
What is the main claim of U.S. Patent No. 5,470,584?
The main claim of U.S. Patent No. 5,470,584 pertains to the dissolution profile of diltiazem, specifying that 0–45% of the total diltiazem should be released within 18 hours.
How does the Hatch-Waxman Act affect this patent?
The Hatch-Waxman Act allows generic manufacturers to file ANDAs, which can include paragraph IV certifications challenging the validity or infringement of the patent, potentially leading to a 30-month stay on FDA approval.
What were the economic implications of the patent dispute between HMR and Andrx?
The dispute delayed the entry of Andrx's generic product into the market, allowing HMR to maintain market exclusivity and significant profits.
How does the Global Dossier impact international patent management?
The Global Dossier provides a single portal for accessing file histories of related applications from participating IP Offices, facilitating the management of international patent families.
What is the significance of the Patent Claims Research Dataset in analyzing this patent?
The dataset provides detailed information on claims from U.S. patents, allowing for the analysis of trends and scope measurements, which can offer insights into the broader patent landscape.
Sources
- In Re Terazosin Hydro - Carmichael v. Southern Coal & Coke Co., 301 U.S. 495, 509, 57 S.Ct. 868, 81 L.Ed. 1245.
- Law360 - U.S. Patent Number 5,470,584: Articles.
- USPTO - Patent Claims Research Dataset.
- USPTO - Search for patents.
- Federal Trade Commission - Untitled - Federal Trade Commission.
