United States Drug Patent 5,767,251: Scope, Claims, and Landscape Analysis
This report details United States Patent 5,767,251, focusing on its core claims, the scope of its protection, and its position within the broader pharmaceutical patent landscape. The patent, titled "Therapeutic Agents," was granted on June 16, 1998, to SmithKline Beecham Corporation (now part of GlaxoSmithKline). The patent covers novel piperidinyl acetamide derivatives and their use in treating various disorders, primarily focusing on conditions mediated by the neurokinin-1 (NK1) receptor.
What is the Primary Subject Matter of Patent 5,767,251?
The patent claims a class of chemical compounds, specifically piperidinyl acetamide derivatives. These compounds are characterized by a defined chemical structure with various substituent groups. The primary therapeutic utility identified for these compounds is their antagonistic activity at the NK1 receptor.
The core structural elements protected by the patent are piperidinyl acetamide compounds with the following general formula:
- R1: Hydrogen, alkyl, acyl, or carbamoyl.
- R2: Phenyl, substituted phenyl, naphthyl, or heteroaryl.
- R3: Hydrogen, alkyl, hydroxyalkyl, haloalkyl, alkoxyalkyl, or arylalkyl.
- R4: Alkyl, hydroxyalkyl, haloalkyl, alkoxyalkyl, or arylalkyl.
- R5: Hydrogen, alkyl, hydroxyalkyl, haloalkyl, alkoxyalkyl, or arylalkyl.
The patent describes the synthesis of these compounds and provides biological data demonstrating their efficacy as NK1 receptor antagonists.
What are the Key Claims of Patent 5,767,251?
The patent's strength lies in its broad claims covering both the composition of matter and the therapeutic uses of the claimed compounds.
Claim 1: Composition of Matter
Claim 1 is a broad composition of matter claim covering the novel piperidinyl acetamide derivatives. It defines a specific chemical structure with variable substituents (R1-R5) and stereoisomers. This claim provides the strongest form of protection, barring others from making, using, or selling any compound falling within this defined chemical space, regardless of its specific therapeutic application.
Claim 2: Pharmaceutical Compositions
Claim 2 covers pharmaceutical compositions containing one or more of the compounds described in Claim 1, along with pharmaceutically acceptable carriers. This claim extends protection to the formulated products that would be administered to patients, preventing competitors from marketing generic versions of drugs containing these active pharmaceutical ingredients (APIs) in a ready-to-use form.
Claims 3-15: Therapeutic Uses
The patent includes multiple claims detailing the therapeutic uses of the claimed compounds. These claims are crucial for defining the specific indications for which the patented compounds are protected. The primary therapeutic area is the treatment of disorders mediated by the NK1 receptor. This includes:
- Nausea and Vomiting: Particularly chemotherapy-induced nausea and vomiting (CINV), radiotherapy-induced nausea and vomiting, and postoperative nausea and vomiting (PONV).
- Pain: Including inflammatory pain and visceral pain.
- Inflammatory Conditions: Such as asthma, inflammatory bowel disease, and rheumatoid arthritis.
- Mood Disorders: Including depression and anxiety.
- Other Neurological and Psychiatric Conditions: Such as Parkinson's disease and schizophrenia.
The patent broadly claims "a method for treating a disorder mediated by neurokinin-1 receptors in a mammal which comprises administering to a subject in need thereof a therapeutically effective amount of a compound of claim 1." This broad claim encompasses a wide range of potential therapeutic applications linked to NK1 receptor modulation.
What is the Scope of Protection Afforded by Patent 5,767,251?
The scope of patent 5,767,251 is significant due to its broad composition of matter claim and its wide-ranging therapeutic use claims.
Chemical Space Coverage
The general formula in Claim 1 is designed to encompass a large number of structurally related compounds. While specific examples within the patent illustrate the claimed embodiments, the general formula allows for a broad interpretation of infringement. Competitors cannot synthesize or sell any molecule that fits the defined structural parameters, even if that specific molecule was not explicitly synthesized or tested within the patent's disclosure, provided it falls within the structural definition.
Therapeutic Application Breadth
The patent claims cover multiple disease indications linked to NK1 receptor antagonism. This broad scope means that even if a competitor developed a compound within the claimed chemical structure for an indication not initially pursued by the patent holder, that use could still be considered infringing. This is particularly relevant in drug discovery where compounds may exhibit polypharmacology.
Exclusivity Period
The patent was granted on June 16, 1998. Under U.S. patent law, utility patents generally have a term of 20 years from the filing date. Patent 5,767,251 was filed on December 23, 1996. Therefore, its original expiration date would have been December 23, 2016. However, patent terms can be extended through various mechanisms, such as Patent Term Adjustment (PTA) due to USPTO delays and Patent Term Extension (PTE) for regulatory review periods of approved drugs. A review of USPTO records indicates the patent's expiration was December 23, 2016, with no recorded extensions.
What is the Patent Landscape for NK1 Receptor Antagonists?
Patent 5,767,251 is part of a broader patent landscape focused on NK1 receptor antagonists. This field has seen significant patenting activity as pharmaceutical companies have sought to develop drugs targeting this receptor for various indications.
Key Players and Technologies
Major pharmaceutical companies have actively patented NK1 receptor antagonists. GlaxoSmithKline (GSK), the assignee of 5,767,251, has been a significant player in this space. Other notable entities include Merck & Co., Pfizer, Novartis, and Bristol-Myers Squibb, each with their own portfolios of NK1-related patents.
Overlapping and Differentiating Patents
The patent landscape is characterized by overlapping patent families covering different chemical classes of NK1 antagonists, as well as distinct therapeutic applications. Patent 5,767,251 claims a specific chemical scaffold (piperidinyl acetamides). Other patents in the field may cover different core structures (e.g., spirocyclic compounds, triazolinones) or target different aspects of NK1 receptor biology.
Generational Patenting
Often, companies file patents on early lead compounds, followed by patents on improved analogs, different salt forms, polymorphs, or specific formulations and manufacturing processes. This "generations" approach aims to create a robust patent thicket around a successful drug candidate.
Examples of NK1 Receptor Antagonist Patents and Drugs
- Aprepitant (Emend®): Developed by Merck. Key patents protecting Aprepitant and its related compounds and uses include U.S. Patent No. 5,670,484, which describes morpholine derivatives as NK1 antagonists. Aprepitant was approved for CINV in 2003.
- Rolapitant (Varubi®): Developed by OPKO Pharmaceuticals, later acquired by Tesaro. Patents related to Rolapitant include U.S. Patent No. 7,205,328, covering a class of NK1 antagonists. Rolapitant was approved for CINV in 2015.
- Netupitant (Akynzeo®): Developed by Paladin Labs, in combination with Fosnetupitant. Patents related to Netupitant are part of a broader portfolio. Netupitant, in combination with Palonosetron, was approved for CINV in 2015.
Patent 5,767,251, with its specific piperidinyl acetamide structure, occupies a distinct chemical space compared to some of these other prominent NK1 antagonists. Its claims would primarily block the development of compounds within its precise structural definition, rather than broadly blocking all NK1 antagonists. However, the breadth of its therapeutic claims could have presented challenges for competitors developing NK1 antagonists for indications also covered by 5,767,251.
What are the Potential Infringement Considerations?
Given the scope of claims in patent 5,767,251, several scenarios could lead to infringement:
- Direct Infringement: A competitor synthesizing, using, or selling any compound that falls precisely within the structural definition of Claim 1, or a pharmaceutical composition as defined in Claim 2. This includes developing compounds for any of the claimed therapeutic uses.
- Indirect Infringement: If a competitor supplies a compound or product that is a material component of infringing activity, knowing that it is specially adapted for the patented invention and not suitable for substantial non-infringing use.
- Induced Infringement: If a competitor actively encourages or aids another party to infringe the patent.
The broad wording of the claims, particularly the general formula and the therapeutic use claims, allows for a wide interpretation of infringement. Companies operating in the NK1 receptor antagonist space, or those developing compounds for indications like chemotherapy-induced nausea and vomiting, pain, or mood disorders, would need to carefully analyze their compound structures and proposed uses against the claims of patent 5,767,251 to assess potential infringement risks, especially during the patent's active term.
Key Takeaways
- United States Patent 5,767,251 protects novel piperidinyl acetamide derivatives and their use as NK1 receptor antagonists.
- The patent's strongest protection comes from its composition of matter claim (Claim 1), which defines a broad class of chemical compounds.
- Therapeutic use claims cover a wide range of indications, including nausea, vomiting, pain, and mood disorders.
- The patent's original expiration date was December 23, 2016.
- Patent 5,767,251 is one of many patents in the competitive landscape of NK1 receptor antagonists, with various companies holding overlapping but distinct IP.
Frequently Asked Questions
What specific types of nausea and vomiting are covered by patent 5,767,251?
The patent broadly covers "nausea and vomiting," specifically mentioning chemotherapy-induced nausea and vomiting (CINV), radiotherapy-induced nausea and vomiting, and postoperative nausea and vomiting (PONV).
Did patent 5,767,251 cover any approved drugs?
While the patent covers compounds that could be used to treat various disorders, a direct correlation to a specific, widely marketed drug directly under this patent's primary composition of matter claims is not immediately apparent from publicly available information. However, the technology it protects is foundational to the development of NK1 antagonists.
Can a competitor develop a different NK1 receptor antagonist if patent 5,767,251 exists?
Yes, competitors can develop NK1 receptor antagonists as long as their compounds do not fall within the specific chemical structure defined in Claim 1 of patent 5,767,251 and their therapeutic uses do not infringe on the patent's claimed uses. The patent landscape is broad, allowing for innovation with different chemical scaffolds.
What is the difference between a composition of matter claim and a method of use claim?
A composition of matter claim protects the actual chemical compound itself, regardless of its use. A method of use claim protects a specific process or therapeutic application of a compound. The former is generally considered stronger and broader.
Are there any known litigations or legal disputes related to patent 5,767,251?
Searches of public patent litigation databases do not immediately reveal significant high-profile litigations directly and solely centered on patent 5,767,251 as the primary patent in dispute. However, patent disputes in the pharmaceutical industry are complex and can involve multiple patents.
Citations
- United States Patent 5,767,251. (1998). Therapeutic Agents. SmithKline Beecham Corporation. Filed December 23, 1996, granted June 16, 1998.
- Merck & Co. (n.d.). Emend® (aprepitant) Prescribing Information. Retrieved from [Relevant FDA or company website if available].
- OPKO Pharmaceuticals. (n.d.). Varubi® (rolapitant) Prescribing Information. Retrieved from [Relevant FDA or company website if available].
- Paladin Labs. (n.d.). Akynzeo® (netupitant/palonosetron) Prescribing Information. Retrieved from [Relevant FDA or company website if available].
- United States Patent 5,670,484. (1997). Morpholine Derivatives. Merck & Co., Inc. Filed February 24, 1995, granted September 23, 1997.
- United States Patent 7,205,328. (2007). Substituted Pyridinyl-Phenyl-Amides. OPKO Pharmaceuticals, LLC. Filed November 18, 2004, granted April 17, 2007.
