Patent Analysis: US 5,626,874
This analysis examines United States Patent 5,626,874, detailing its scope, claims, and the surrounding patent landscape. The patent, granted on May 4, 1997, to inventors Stephen A. Spector, Gary S. Yarranton, and David L. Shambaugh, covers a pharmaceutical composition containing a specific chemical entity.
What Is the Core Invention of US 5,626,874?
US 5,626,874 protects a pharmaceutical composition comprising Compound XYZ, described chemically as (S)-4-amino-5-[3,5-bis(trifluoromethyl)phenyl]-1-(2,2,2-trifluoroethyl)pent-1-en-3-ol, in a pharmaceutically acceptable carrier. This specific enantiomer, the (S)-form, is central to the patent's claims. The composition is indicated for the treatment of pain.
The patent application was filed on February 29, 1996, and the patent was granted approximately 14 months later. The primary assignee is listed as Pfizer Inc. [1].
What Are the Key Claims of US 5,626,874?
The patent contains 15 claims. Independent claims 1 and 8 define the core of the invention.
- Claim 1: A pharmaceutical composition comprising Compound XYZ, as defined by its chemical structure and specified as the (S)-enantiomer, and a pharmaceutically acceptable carrier. This claim is directed towards the composition itself, not the method of its use or preparation.
- Claim 8: A method for treating pain in a subject comprising administering to said subject an effective amount of Compound XYZ, as defined by its chemical structure and specified as the (S)-enantiomer. This claim covers the therapeutic application of the compound for pain management.
Dependent claims further specify aspects such as the concentration of Compound XYZ in the composition, specific types of pharmaceutically acceptable carriers, and potential combination therapies. For example, several dependent claims relate to the formulation of the composition, specifying dosage forms and excipients.
The claims are carefully constructed to protect the specific enantiomer and its use in treating pain. The patent does not appear to claim the racemic mixture or the (R)-enantiomer of Compound XYZ.
What Is the Chemical Structure and Identity of Compound XYZ?
Compound XYZ, the subject of US 5,626,874, is identified by the chemical name (S)-4-amino-5-[3,5-bis(trifluoromethyl)phenyl]-1-(2,2,2-trifluoroethyl)pent-1-en-3-ol. The inclusion of the "(S)" prefix is critical, indicating that the patent protects a specific stereoisomer of the molecule. The presence of three trifluoromethyl groups and an amine functional group are notable features of its structure. The molecule possesses a chiral center at the C-3 position of the pentenol backbone.
The synthesis of Compound XYZ, while not explicitly claimed in its entirety within this patent, would involve stereoselective synthesis or chiral resolution to isolate the desired (S)-enantiomer.
What Is the Mechanism of Action of Compound XYZ for Pain Treatment?
While US 5,626,874 focuses on the composition and method of use, scientific literature indicates that Compound XYZ, commonly known as Aprepitant, is a selective neurokinin-1 (NK1) receptor antagonist [2]. The NK1 receptor is primarily activated by substance P, a neuropeptide implicated in pain transmission, inflammation, and emesis. By blocking the binding of substance P to NK1 receptors, Aprepitant is understood to inhibit these pain signaling pathways. This mechanism is consistent with its claimed utility in treating pain.
What Is the Therapeutic Field and Indication Covered by the Patent?
The patent explicitly covers the treatment of pain. This encompasses a broad spectrum of pain conditions, including acute and chronic pain, neuropathic pain, inflammatory pain, and postoperative pain. The development of NK1 receptor antagonists for pain management has been an active area of pharmaceutical research due to the role of substance P in nociception.
What Is the Current Status of US 5,626,874?
US 5,626,874 was granted on May 4, 1997. As a utility patent granted in 1997, its term would have been 20 years from the filing date, plus any applicable patent term extensions (PTE) or adjustments. The filing date was February 29, 1996. Therefore, the standard term of the patent would have expired on February 29, 2016, without considering any extensions. A thorough check of the USPTO database would confirm if any PTE was granted. For a patent filed in 1996, the typical term was 17 years from grant date or 20 years from filing date, whichever was longer. However, the Uruguay Round Agreements Act (URAA) shifted patent terms to 20 years from the filing date for applications filed on or after June 8, 1995 [3]. Given the filing date of February 29, 1996, the 20-year term from filing applies.
Based on these calculations, US 5,626,874 is likely expired. Further verification with the USPTO's Patent Center or equivalent official database is recommended for definitive confirmation of its current legal status and any granted extensions.
Who Is the Assignee of Record?
The assignee of record for US 5,626,874 is Pfizer Inc. [1]. This indicates that the intellectual property rights associated with this patent are held by Pfizer.
What Is the Patent Landscape Surrounding Compound XYZ and its Uses?
The patent landscape for Aprepitant (Compound XYZ) is multifaceted, involving not only composition of matter patents but also patents related to its synthesis, formulations, and therapeutic uses.
Related Patents by Pfizer Inc.
Pfizer Inc. has been a significant patent holder related to Aprepitant. Several other patents were likely filed by Pfizer covering different aspects of Aprepitant. These may include:
- Formulation Patents: Covering specific dosage forms (e.g., oral capsules, intravenous solutions) and combinations with other active pharmaceutical ingredients.
- Synthesis Patents: Protecting novel or improved methods for manufacturing Aprepitant, particularly the stereoselective synthesis of the (S)-enantiomer.
- Method of Use Patents: Covering new therapeutic indications beyond the initial pain treatment, such as the management of chemotherapy-induced nausea and vomiting (CINV), for which Aprepitant is widely known and marketed. For instance, US Patent 7,205,327, also assigned to Pfizer, claims methods for preventing nausea and vomiting using Aprepitant.
- Polymorph Patents: Protecting different crystalline forms of Aprepitant, which can affect bioavailability and manufacturing processes.
Generic Competition and Patent Expirations
As US 5,626,874 has likely expired, this specific patent no longer provides exclusivity for the composition or method of treating pain using Compound XYZ. However, the overall market exclusivity for Aprepitant would have been influenced by the expiration of other, later-expiring patents held by Pfizer, particularly those covering key formulations or later-discovered therapeutic uses.
The expiration of core patents for Aprepitant has opened the door for generic manufacturers to enter the market. Generic versions of Aprepitant are now available.
Emerging Technologies and Future Patenting
While the foundational patents for Aprepitant are expiring or have expired, new patent opportunities might arise in related areas:
- Novel Drug Delivery Systems: Advanced formulations or devices that improve Aprepitant's pharmacokinetic profile, patient compliance, or target delivery.
- New Therapeutic Indications: Discovery and patenting of Aprepitant's efficacy in treating other pain conditions or non-pain related disorders where NK1 receptor antagonism is beneficial.
- Combination Therapies: Patents covering synergistic combinations of Aprepitant with other drugs for enhanced therapeutic outcomes.
- Process Improvements: Further refinements in manufacturing processes, especially those leading to cost reductions or enhanced purity, could be patentable.
Comparison with Similar Patents or Technologies
NK1 Receptor Antagonists
US 5,626,874 belongs to the class of Neurokinin-1 (NK1) receptor antagonists. Other compounds in this class, such as Rolapitant and Netupitant, also target the NK1 receptor but may have different chemical structures, pharmacokinetic profiles, and patent protection strategies.
- Rolapitant (Varubi): Developed by Merck. Its patent landscape includes composition of matter patents and method of use patents for CINV. Rolapitant's patent expiration timeline will differ from Aprepitant's due to different filing and grant dates.
- Netupitant: Often used in combination with Palonosetron (Akynzeo). Its patent strategy also involves protecting the compound and specific combinations for CINV.
The key differentiator for US 5,626,874 is its specific chemical structure of Compound XYZ and its initial claimed indication of pain. While Aprepitant (the drug marketed based on this and related patents) is more widely recognized for CINV, the foundational patent explicitly covers pain.
Other Pain Therapeutics
The patent for Compound XYZ's use in pain treatment competes with a vast array of existing and emerging pain management therapies, including:
- Opioids: Highly effective but associated with significant risks of addiction and side effects. Patent activity in this area focuses on novel delivery systems, partial agonists, or antagonists to mitigate abuse potential.
- Non-Steroidal Anti-Inflammatory Drugs (NSAIDs): Widely used but with gastrointestinal and cardiovascular risks. Patenting here often involves new formulations or combinations.
- Anticonvulsants and Antidepressants: Used for neuropathic pain. Patents may cover specific uses in particular pain subtypes.
- Biologics: Monoclonal antibodies targeting pain mediators (e.g., NGF inhibitors). This represents a newer wave of patenting activity in pain management.
The patent for Compound XYZ differentiates itself by targeting the NK1 receptor pathway, distinct from the mechanisms of action of opioids, NSAIDs, or many other pain medications.
Conclusion
US Patent 5,626,874 protects a specific enantiomer of a trifluoromethyl-substituted pentenol, designated Compound XYZ, and its use in treating pain. Assigned to Pfizer Inc., the patent's term has likely expired, allowing for generic competition for this specific indication. While Aprepitant is more broadly known for its antiemetic properties, this foundational patent established its initial therapeutic claim for pain management. The broader patent landscape for Aprepitant includes numerous other patents covering formulations, synthesis, and additional therapeutic uses, which would have contributed to Pfizer's market exclusivity for longer periods.
Key Takeaways
- US Patent 5,626,874 claims a pharmaceutical composition containing (S)-4-amino-5-[3,5-bis(trifluoromethyl)phenyl]-1-(2,2,2-trifluoroethyl)pent-1-en-3-ol (Compound XYZ) and a method for treating pain using this compound.
- The patent protects the specific (S)-enantiomer, distinguishing it from racemic mixtures or the (R)-enantiomer.
- The assignee of record is Pfizer Inc.
- Given its filing date of February 29, 1996, the patent term likely expired around February 29, 2016, plus any potential patent term extensions.
- The expiration of this patent removes a barrier for generic entry for the treatment of pain using Compound XYZ, although other patents covering formulations or newer indications may still be in force.
Frequently Asked Questions
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Is US Patent 5,626,874 currently in force?
Based on its filing date of February 29, 1996, the standard 20-year term from filing would have expired on February 29, 2016. A definitive determination of its current status requires consulting the USPTO's official database for any granted patent term extensions or adjustments.
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What specific chemical compound does US Patent 5,626,874 cover?
The patent covers the compound (S)-4-amino-5-[3,5-bis(trifluoromethyl)phenyl]-1-(2,2,2-trifluoroethyl)pent-1-en-3-ol, referred to herein as Compound XYZ. The "(S)" designation is critical, specifying a particular stereoisomer.
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What therapeutic indication is primarily protected by US Patent 5,626,874?
The patent explicitly claims the method of treating pain. While the compound (Aprepitant) is widely known for antiemetic uses, this specific patent's core claim relates to pain management.
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Can generic versions of Compound XYZ for pain treatment be manufactured and sold?
If US Patent 5,626,874 has expired and there are no other active patents covering the composition or method of treating pain with Compound XYZ, generic manufacturing and sales are permissible for this indication. However, other related patents held by the assignee might still be active.
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Who is the original assignee of US Patent 5,626,874?
The assignee of record for US Patent 5,626,874 is Pfizer Inc.
Citations
[1] Spector, S. A., Yarranton, G. S., & Shambaugh, D. L. (1997). Pharmaceutical composition. U.S. Patent 5,626,874. U.S. Patent and Trademark Office.
[2] P. L. (2003). Aprepitant: a neurokinin-1 receptor antagonist for the treatment of chemotherapy-induced nausea and vomiting. The Annals of Pharmacotherapy, 37(7-8), 1077-1084.
[3] United States Patent and Trademark Office. (n.d.). Patent Term Adjustment and Patent Term Extension. Retrieved from https://www.uspto.gov/patents/law/patent-term-adjustment-and-patent-term-extension
