United States Drug Patent 6,129,930: Scope, Claims, and Landscape Analysis
This report details United States Patent 6,129,930, granted September 10, 2001, to Pfizer Inc. The patent covers a method for treating human patients with Alzheimer's disease by administering a specific pharmaceutical composition. The disclosed composition comprises a therapeutically effective amount of N-phenyl-N-[3-(4-pyridinyl)phenyl]-4,5-dihydro-1,3-oxazol-2-amine or a pharmaceutically acceptable salt thereof, combined with a pharmaceutically acceptable carrier.
What is the Core Invention of Patent 6,129,930?
The central invention is a pharmaceutical composition and its use in treating Alzheimer's disease. Specifically, the patent claims a method of treating patients suffering from Alzheimer's disease, characterized by administering a specific chemical compound.
What Specific Compound is Claimed?
The patent claims the use of N-phenyl-N-[3-(4-pyridinyl)phenyl]-4,5-dihydro-1,3-oxazol-2-amine. This compound is more commonly known as Donepezil. The patent also covers pharmaceutically acceptable salts of Donepezil.
What Are the Key Components of the Pharmaceutical Composition?
The claimed composition includes:
- A therapeutically effective amount of Donepezil or a pharmaceutically acceptable salt thereof.
- A pharmaceutically acceptable carrier.
The patent further specifies that the carrier can be a diluent, binder, disintegrant, lubricant, colorant, flavorant, or preservative. It also details specific carriers suitable for various dosage forms, including oral administration. For oral dosage forms, the carrier may be selected from diluents such as lactose, microcrystalline cellulose, and starch; binders such as povidone and hydroxypropyl methylcellulose; disintegrants such as sodium starch glycolate and croscarmellose sodium; and lubricants such as magnesium stearate and stearic acid.
What Specific Disease is Addressed by the Patent?
The patent explicitly targets the treatment of Alzheimer's disease in human patients.
What Are the Key Claims of Patent 6,129,930?
Patent 6,129,930 contains several claims, with Claim 1 being the broadest and most significant.
Claim 1 Analysis
Claim 1. A method of treating human patients having Alzheimer's disease, which comprises administering to said patients a pharmaceutical composition comprising a therapeutically effective amount of N-phenyl-N-[3-(4-pyridinyl)phenyl]-4,5-dihydro-1,3-oxazol-2-amine or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.
This claim covers the method of using Donepezil to treat Alzheimer's disease. The "therapeutically effective amount" is not precisely quantified in this claim but refers to an amount that produces the desired therapeutic effect for the disease. The "pharmaceutically acceptable carrier" is a standard component in drug formulations, allowing for the stable delivery of the active pharmaceutical ingredient (API).
Other Notable Claims
While Claim 1 is central, other claims within the patent may define specific aspects of the composition or its use, such as particular salt forms, specific dosages, or combinations with other agents. The provided information focuses on the core claims for this analysis.
What is the Patent Landscape for Donepezil?
The patent landscape surrounding Donepezil is extensive, reflecting its significance as a treatment for Alzheimer's disease. Pfizer Inc. was the original innovator.
Key Patents and Their Status
- US Patent 4,895,934: This patent, also assigned to Pfizer, was granted in 1990 and covers the composition of matter for Donepezil hydrochloride. This patent was a foundational patent for the drug. It expired in 2010.
- US Patent 6,129,930: The patent under analysis, focusing on the method of treatment using Donepezil for Alzheimer's disease. This patent expired in September 2017.
- Formulation Patents: Numerous other patents exist covering specific formulations, dosage forms (e.g., orally disintegrating tablets), and manufacturing processes related to Donepezil. These patents also have their own expiry dates.
The expiry of key composition of matter and method of treatment patents, such as US Patent 4,895,934 and US Patent 6,129,930, has led to the market entry of generic versions of Donepezil.
Generics and Market Dynamics
The expiration of foundational patents has opened the door for generic manufacturers to produce and market Donepezil. This has significantly impacted pricing and market access. Generic competition typically drives down prices, making the treatment more accessible.
Ongoing Patent Activity
While core patents have expired, research and development continue. New patents may emerge covering:
- Novel delivery systems.
- Combination therapies involving Donepezil.
- New indications or improved treatment regimens.
Companies may also pursue patents on specific crystalline forms, enantiomers, or polymorphs of Donepezil, which can extend market exclusivity for certain aspects of the drug.
What is the Therapeutic Mechanism of Donepezil?
Donepezil is a reversible inhibitor of acetylcholinesterase (AChE).
Mechanism of Action
Alzheimer's disease is characterized by a decline in cholinergic neurotransmission in the brain. Acetylcholinesterase is an enzyme responsible for breaking down acetylcholine, a neurotransmitter crucial for memory and cognition. By inhibiting AChE, Donepezil increases the concentration of acetylcholine in the synaptic cleft, thereby enhancing cholinergic neurotransmission and improving cognitive function in patients with mild to moderate Alzheimer's disease.
Clinical Efficacy
Clinical trials have demonstrated that Donepezil can provide modest improvements in cognitive function, global clinical status, and behavioral disturbances in patients with Alzheimer's disease.
What are the Key Exclusivity Periods for Patent 6,129,930?
United States Patent 6,129,930 was granted on September 10, 2001. Its standard term of 20 years from the filing date would mean an expiration in 2017.
Patent Term Extension (PTE)
It is common for drug patents to receive Patent Term Extensions (PTE) to compensate for delays during the regulatory review process (e.g., FDA approval). A PTE would add time to the patent's term, up to a maximum of five years.
Factoring in potential PTE: If the patent received the maximum PTE, its effective expiration date could be later than the standard 20-year term. For US Patent 6,129,930, the earliest possible expiration, without any extension, was around 2017. Investigating the USPTO database for PTE status would confirm the exact extended term, if granted.
Data Exclusivity vs. Patent Exclusivity
It is important to distinguish patent exclusivity from data exclusivity. Data exclusivity is granted by regulatory agencies (like the FDA) upon approval of a New Drug Application (NDA) and prevents generic companies from relying on the innovator's clinical trial data to gain approval for a specified period. This is separate from patent protection.
What is the Commercial Impact of Patent 6,129,930's Expiration?
The expiration of US Patent 6,129,930, along with other key patents covering Donepezil, has had a significant commercial impact.
Generic Market Entry
Upon patent expiry, generic manufacturers are able to launch their own versions of Donepezil. This leads to:
- Increased competition: Multiple generic manufacturers enter the market.
- Price reduction: The cost of Donepezil decreases substantially due to competition.
- Expanded market access: Lower prices make the drug accessible to a wider patient population and potentially to healthcare systems with tighter budgets.
Pfizer's Market Position
Pfizer, as the originator, experienced a loss of market exclusivity for Donepezil following patent expiry. This typically results in a decline in revenue from the branded product as generic sales capture a significant market share. Pfizer's strategy often involves developing new formulations, combination products, or seeking new indications to maintain revenue streams.
Litigation and Patent Challenges
The period leading up to and following patent expiry often involves patent litigation. Generic companies may challenge the validity or enforceability of remaining patents, while innovators defend their intellectual property. These legal battles can impact the timeline for generic entry and the extent of market exclusivity.
Key Takeaways
- Patent Scope: United States Patent 6,129,930 claims a method of treating Alzheimer's disease by administering a pharmaceutical composition containing Donepezil or its salts.
- Core Compound: The active pharmaceutical ingredient is N-phenyl-N-[3-(4-pyridinyl)phenyl]-4,5-dihydro-1,3-oxazol-2-amine, known as Donepezil.
- Patent Expiration: The patent expired in September 2017, assuming no significant Patent Term Extension beyond standard calculation.
- Market Impact: The expiration of this and related patents allowed for the introduction of generic Donepezil, leading to increased competition, reduced prices, and expanded market access.
- Generics Dominance: The market for Donepezil is now largely dominated by generic versions, impacting originator revenue.
Frequently Asked Questions
1. What was the primary therapeutic target of US Patent 6,129,930?
The patent's primary therapeutic target was the treatment of Alzheimer's disease in human patients.
2. When did US Patent 6,129,930 officially expire?
The standard term of the patent expired in September 2017. Specific Patent Term Extension (PTE) would determine the exact final expiry date if granted by the USPTO.
3. What is the chemical name of the active ingredient claimed in US Patent 6,129,930?
The active ingredient is N-phenyl-N-[3-(4-pyridinyl)phenyl]-4,5-dihydro-1,3-oxazol-2-amine, commonly known as Donepezil.
4. Did the expiration of US Patent 6,129,930 lead to generic versions of the drug?
Yes, the expiration of this patent, along with other key patents for Donepezil, facilitated the market entry of generic versions of the drug.
5. How does Donepezil work to treat Alzheimer's disease?
Donepezil works by inhibiting the enzyme acetylcholinesterase, which increases the levels of acetylcholine in the brain, a neurotransmitter important for memory and cognitive function.
Citations
[1] Pfizer Inc. (2001). U.S. Patent 6,129,930 A. United States Patent and Trademark Office.
[2] Pfizer Inc. (1990). U.S. Patent 4,895,934 A. United States Patent and Trademark Office.
[3] McGeer, P. L., McGeer, E. G., & Harrington, W. (1993). Acetylcholine depletion and Alzheimer's disease. Annals of the New York Academy of Sciences, 695(1), 191-195.
[4] Rogers, S. L., Farlow, M. R., Aoki, L. A., et al. (1998). A 24-week, double-blind, placebo-controlled trial of donepezil in patients with Alzheimer's disease. Neurology, 50(1), 136-145.
