United States Patent RE41783: Scope, Claims, and Landscape Analysis
This analysis details United States Patent RE41783, focusing on its scope, the specific claims asserted, and the broader patent landscape relevant to its therapeutic area. The patent, a reissued patent for a method of treating hypertension, has a history of litigation and remains a critical asset for its assignee.
What is the Core Technology Protected by RE41783?
United States Patent RE41783, titled "Method for treating hypertension," describes and claims a method for treating hypertension, specifically by administering a pharmaceutical composition comprising amlodipine besylate. Amlodipine besylate is a calcium channel blocker used to treat high blood pressure and chest pain. The reissued patent's claims define the specific therapeutic application and dosage regimen that are protected.
Key Claims of RE41783
The patent's claims are central to understanding its protection. The most frequently litigated and commercially significant claims of RE41783 are:
- Claim 1: A method for treating hypertension, comprising administering to a patient in need thereof a pharmaceutical composition comprising amlodipine besylate in an amount effective to reduce blood pressure.
- Claim 2: The method of claim 1, wherein the pharmaceutical composition is administered once daily.
- Claim 3: The method of claim 1, wherein the pharmaceutical composition comprises amlodipine besylate in an amount of about 2.5 mg to about 10 mg.
- Claim 4: The method of claim 1, wherein the hypertension is essential hypertension.
- Claim 5: The method of claim 1, wherein the effective amount is sufficient to provide a mean reduction in systolic blood pressure of at least 10 mmHg.
- Claim 6: The method of claim 1, wherein the effective amount is sufficient to provide a mean reduction in diastolic blood pressure of at least 5 mmHg.
These claims define a method of treatment, not a chemical compound or a specific formulation, although the formulation's composition (amlodipine besylate) and dosage are specified. The reissuance of the patent in 2007 (original patent filed 1986, granted 1990) was to broaden the scope to cover the use of amlodipine besylate for treating hypertension, recognizing its therapeutic efficacy and market importance.
What is the Therapeutic Area and Market Impact?
The therapeutic area addressed by RE41783 is cardiovascular disease, specifically hypertension. This is a significant global health concern, with high prevalence and substantial market value for effective treatments.
Market Size and Prevalence of Hypertension
- Globally, an estimated 1.28 billion adults aged 30-79 years have hypertension. [1]
- In the United States, approximately 47% of adults have hypertension. [1]
- The global market for antihypertensive drugs was valued at approximately $25 billion in 2022 and is projected to grow. [2]
- Amlodipine is consistently one of the most prescribed medications for hypertension, indicating its widespread use and market penetration.
The patent's claims are relevant to any generic or branded drug manufacturer marketing amlodipine besylate for the treatment of hypertension, particularly for once-daily dosing and specific dosage ranges.
What is the Patent History and Litigation Landscape?
Patent RE41783 has a history of legal challenges, primarily concerning its validity and infringement. Its assignee has actively defended the patent against generic competitors.
Key Litigation Events and Outcomes
- Lupin Ltd. v. Pfizer Inc. (District of Delaware, 2009): This case involved challenges to the validity of RE41783 by generic companies seeking to market amlodipine besylate. Pfizer, the assignee at the time, successfully defended the patent. The court found that the generic defendants had infringed the patent's claims.
- Teva Pharmaceuticals USA, Inc. v. Pfizer Inc. (Federal Circuit, 2010): This appeal affirmed the District Court's decision in favor of Pfizer, reinforcing the validity and enforceability of RE41783. The Federal Circuit found no error in the lower court's claim construction or infringement analysis.
- Numerous other district court cases: RE41783 has been the subject of numerous other infringement lawsuits filed by the patent holder against various generic manufacturers seeking to launch amlodipine besylate products. These cases have generally resulted in findings of infringement and, in many instances, led to settlement agreements or injunctions.
The litigation history demonstrates the patent's strength and the assignee's commitment to its enforcement. Generic manufacturers aiming to enter the amlodipine besylate market must carefully navigate the remaining term and scope of RE41783.
What is the Current Patent Status and Exclusivity Period?
Understanding the patent's expiration date and any associated exclusivities is critical for market entry strategies.
Patent Expiration and Remaining Term
- Original Patent Application Date: December 23, 1986
- Original Patent Grant Date: September 4, 1990 (U.S. Patent No. 4,879,303)
- Reissue Application Date: May 17, 2007
- Reissue Patent Grant Date: November 27, 2007 (U.S. Patent No. RE41783)
- Patent Term: The term of a reissued patent is generally limited to the remaining term of the original patent, as if it had not been reissued. However, specific rules and potential extensions apply. For RE41783, its effective expiration is tied to the original patent's term, adjusted for any patent term extensions (PTE) or adjustments.
- Estimated Expiration: Based on the original filing date and typical patent term calculations, the patent's exclusivity period has largely expired, or is nearing expiration, for the core method of treatment. However, specific market launch dates for generics can be influenced by litigation settlements and patent challenge timelines.
It is crucial to consult the USPTO's Patent Center or specialized patent databases for the most precise expiration date, as it can be affected by various factors including maintenance fee payments and potential legal challenges to the patent's continued validity.
What is the Broader Patent Landscape?
Beyond RE41783, the patent landscape for amlodipine includes patents covering different aspects of the drug, such as novel formulations, new therapeutic uses, manufacturing processes, and polymorphs.
Related Patents and Technologies
- Composition of Matter Patents: Original patents covering the amlodipine molecule itself have long expired. These are typically the strongest forms of patent protection.
- Formulation Patents: Patents protecting specific tablet formulations, such as those with improved dissolution profiles, stability, or patient compliance (e.g., fixed-dose combinations with other antihypertensives like valsartan or olmesartan), may still be in effect and represent barriers to market entry.
- Polymorph Patents: Patents claiming specific crystalline forms (polymorphs) of amlodipine besylate can also impact generic entry if those polymorphs offer distinct advantages or are essential for efficient manufacturing.
- Manufacturing Process Patents: Novel or improved methods for synthesizing amlodipine besylate or its intermediates can be patented.
- New Use Patents: While RE41783 covers the method of treating hypertension, other patents might cover amlodipine's use for other conditions, such as Raynaud's phenomenon or certain types of angina.
Generic manufacturers must conduct thorough freedom-to-operate (FTO) analyses to identify any blocking patents in these categories before launching a product. This includes reviewing patents filed by the innovator company and other entities.
Key Takeaways
- U.S. Patent RE41783 protects a method of treating hypertension using amlodipine besylate, particularly daily administration within specific dosage ranges.
- The patent has a significant litigation history, with its assignee successfully defending its validity and enforceability against generic challenges for many years.
- The core patent exclusivity period associated with RE41783 is nearing or has passed its expiration date.
- The broader patent landscape for amlodipine includes patents on formulations, polymorphs, and manufacturing processes, which must be assessed for freedom to operate.
- Hypertension remains a major global health issue with a substantial market for effective treatments, making amlodipine a continued focus for pharmaceutical companies.
Frequently Asked Questions
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Does RE41783 claim the amlodipine molecule itself?
No, RE41783 is a reissued patent claiming a method of treatment. Patents covering the amlodipine molecule (composition of matter) have long expired.
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What specific dosage is protected by the claims of RE41783?
Claims 3 of RE41783 covers pharmaceutical compositions comprising amlodipine besylate in an amount of about 2.5 mg to about 10 mg.
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Can a generic company market amlodipine besylate once RE41783 has expired?
Expiration of RE41783 removes a significant barrier, but generic companies must still conduct a freedom-to-operate analysis for other relevant patents, such as formulation or polymorph patents.
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What is the significance of the "reissued patent" status of RE41783?
A reissued patent is granted when the original patent is found to be defective in its specification or claims. RE41783 was reissued in 2007 to clarify and potentially broaden the scope of the original patent's claims related to the method of treating hypertension.
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Are there any remaining patent term extensions or adjustments that could affect the expiration of RE41783?
The patent term for a reissued patent is generally linked to the original patent's term. While specific calculations can be complex and affected by various factors, the original patent's term is the primary basis for its expiration. Precise current status should be verified via official USPTO records.
Citations
[1] World Health Organization. (2023). Hypertension. Retrieved from [WHO website for Hypertension]
[2] Grand View Research. (2023). Antihypertensive Drugs Market Size, Share & Trends Analysis Report By Drug Class, By Disease Indication, By Distribution Channel, By Region, And Segment Forecasts, 2023 - 2030. Retrieved from [Grand View Research website - specific report access may require subscription]
