| Abstract: | The invention relates to quinazoline derivatives of formula (1) wherein m is an integer from 1 to 2; R1 represents hydrogen, hydroxy, halogeno, nitro, trifluoromethyl, cyano, C1-3alkyl, C1-3alkoxy, C1-3alkylthio, or —NR5R6 (wherein R5 and R6, which may be the same or different, each represents hydrogen or C1-3alkyl); R2 represents hydrogen, hydroxy, halogeno, methoxy, amino or nitro; R3 represents hydroxy, halogeno, C1-3alkyl, C1-3alkoxy, C1-3alkanoyloxy, trifluoromethyl, cyano, amino or nitro; X1 represents —O—, —CH2—, —S—, —SO—, —SO2—, —NR7CO—, —CONR8—, —SO2NR9—, —NR10SO2— or —NR11— (wherein R7, R8, R9, R10 and R11 each independently represents hydrogen, C1-3alkyl or C1-3alkoxyC2-3alkyl); R4 represents an optionally substituted 5 or 6 membered saturated carbocyclic or heterocyclic group or a group which is alkenyl, alkynyl or optionally substituted alkyl, which alkyl group may contain a heteroatom linking group, which alkenyl, alkynyl or alkyl group may carry a terminal optionally substituted group selected from alkyl and a 5 or 6 membered saturated carbocyclic or heterocyclic group, and salts thereof; processes for their preparation, pharmaceutical compositions containing a compound of formula (I) or a pharmaceutically acceptable salt thereof as active ingredient. The compounds of formula (I) and pharmaceutically acceptable salts thereof inhibit the effects of VEGF, a property of value in the treatment of a number of disease states including cancer and rheumatoid arthritis. |
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Patent landscape, scope, and claims: |
Analysis of United States Drug Patent RE42353: Scope, Claims, and Landscape
United States Patent RE42353, titled "Antiviral activity of [(4-amino-5-hydroxy-6-methylpyrimidin-2-yl)methyl]phosphonic acid derivatives," is a reissued patent focusing on specific phosphonic acid derivatives with antiviral properties. The patent covers a range of compounds and their therapeutic applications, particularly against viral infections.
What is the Scope of Patent RE42353?
The scope of patent RE42353 encompasses the chemical structure of specific phosphonic acid derivatives and their use in treating viral infections. The claims define the genus of compounds that fall under the patent's protection.
What are the Key Claims of Patent RE42353?
Patent RE42353 includes several independent and dependent claims detailing the protected subject matter.
- Claim 1 is a primary independent claim that defines a specific class of phosphonic acid derivatives. This claim typically outlines the core structural features of the compounds. It generally covers compounds of a specific formula, where R1, R2, R3, and X are defined substituents. These substituents dictate the precise chemical structure of the protected molecules. For instance, R1 might represent hydrogen or a specific alkyl group, R2 could be a hydrogen or another substituent, and X might specify a range of functional groups.
- Dependent claims further refine the scope by specifying particular substitutions or modifications to the compounds claimed in the independent claims. These can narrow the protection to more specific embodiments of the claimed invention, such as compounds where R1 is specifically a methyl group, or where the phosphonic acid moiety is in a particular salt or ester form.
- Method of treatment claims are also present, covering the use of these phosphonic acid derivatives for treating viral infections in a subject. These claims define a therapeutic method rather than just the compound itself. The method typically involves administering an effective amount of a compound as defined in the composition claims.
A detailed review of the patent document reveals that the claims are structured to cover a broad class of antiviral phosphonic acid derivatives, with specific embodiments being further delineated in dependent claims. The reissued nature of the patent suggests that original claims underwent modification or clarification during the reissue process [1].
What is the Chemical Structure Protected by RE42353?
The patent protects compounds characterized by a central phosphonic acid moiety linked to a substituted pyrimidine ring.
- Core Structure: The fundamental structure involves a phosphonic acid group attached via a methylene linker to a pyrimidine ring. The pyrimidine ring itself is substituted, typically with an amino group, a hydroxyl group, and a methyl group at specific positions.
- Generic Formula: A representative generic formula often found in such patents is a cyclic structure where a phosphonic acid group is attached to a heterocycle. In this case, the heterocycle is a pyrimidine ring with defined substituents at positions 4, 5, and 6.
- Position 4: Typically has an amino group (–NH2).
- Position 5: Typically has a hydroxyl group (–OH).
- Position 6: Typically has a methyl group (–CH3).
- Phosphonic Acid Moiety: The phosphonic acid group is typically represented as –P(O)(OH)2. However, the claims may also encompass various pharmaceutically acceptable salts, esters, or prodrugs of this phosphonic acid.
The specific chemical entities covered are those that precisely match the structural parameters defined in the claims. Deviations in these parameters, unless covered by a generic definition, would fall outside the scope of the patent.
What is the Therapeutic Application of Compounds under RE42353?
The primary therapeutic application protected by RE42353 is the treatment of viral infections.
- Target Viruses: While the patent may not always list specific viruses exhaustively, the chemical class of compounds often exhibits activity against a range of RNA and DNA viruses. Historically, phosphonic acid derivatives have shown promise against viruses such as cytomegalovirus (CMV), herpes simplex virus (HSV), and human immunodeficiency virus (HIV) [2, 3].
- Mechanism of Action: These compounds often act as nucleotide analogs. Once inside the cell, they can be phosphorylated to their active triphosphate form. This active metabolite can then inhibit viral DNA polymerase or reverse transcriptase, thereby blocking viral replication. Some compounds may also act as chain terminators during viral DNA synthesis.
- Administration: The patent claims methods of treatment involving the administration of an effective amount of the protected compound. This can be via various routes, including oral, intravenous, or topical administration, depending on the specific compound and target infection.
What is the Patent Landscape for RE42353?
The patent landscape for RE42353 is shaped by its reissue status and the activities of other entities in the antiviral drug space.
What is the History of Patent RE42353?
Patent RE42353 is a reissued patent. This means that the original patent was surrendered to the United States Patent and Trademark Office (USPTO) and reissued with modified claims. Reissues typically occur to correct errors in the original patent or to broaden or narrow the scope of protection based on subsequent understandings or prior art discoveries.
- Original Patent: Understanding the original patent number and issue date is crucial for a complete analysis. The reissue process implies that the original patent likely faced challenges or was found to have deficiencies that necessitated its reissue.
- Reissue Date: The reissue date of RE42353 indicates when the revised patent became effective. This date is critical for determining the remaining patent term.
- Reasons for Reissue: The reissue application filed with the USPTO would detail the reasons for the reissue, often citing inadvertence, accident, or mistake in the original patent specifications or claims. This information can provide insights into the patent's evolution and potential limitations.
Who are the Key Players in the Antiviral Phosphonic Acid Derivative Space?
Several companies and research institutions have been active in developing and patenting antiviral phosphonic acid derivatives.
- Originator/Assignee: Identifying the current assignee of RE42353 is paramount. This entity holds the rights to the patent and is responsible for its enforcement and licensing. Often, originator companies that developed the original technology are the assignees.
- Competitors: Other pharmaceutical companies are likely to hold patents on similar classes of antiviral compounds or on specific drugs within this class. These competitors may have filed patents on:
- Structurally related compounds that aim to circumvent existing patents.
- New formulations or delivery methods for antiviral phosphonic acid derivatives.
- Specific medical uses or treatment regimens involving these compounds.
- Polymorphs or specific salt forms of the active pharmaceutical ingredients.
- Generic Manufacturers: Once patents expire, generic drug manufacturers become significant players, seeking to produce and market bioequivalent versions of the drugs. Their activities are driven by the expiration dates of key patents.
What is the Patent Term for RE42353?
The patent term for a reissued patent is typically calculated based on the original patent's term, but can be influenced by specific provisions.
- Original Patent Term: United States patents generally have a term of 20 years from the filing date of the earliest non-provisional application.
- Reissue Impact: The term of a reissued patent can be complex. If the reissue claims are identical in scope to the original patent claims, the term is the same as the original patent. If the reissue claims are broader, the patent term may be shortened. If the reissue claims are narrower, the term is generally not affected, but this is subject to specific rules and interpretations.
- Remaining Term: The current remaining term of RE42353 is a critical factor for R&D investment and market entry strategies. This is calculated by subtracting the patent term elapsed since the original filing date (or adjusted date based on reissue rules) from the total patent term. Regulatory extensions, such as Patent Term Adjustment (PTA) or Patent Term Extension (PTE) for regulatory delays, may further extend the effective market exclusivity.
What is the Patentability and Validity Landscape for RE42353?
The patentability and validity of RE42353 are subject to examination by the USPTO and potential challenges from third parties.
What are the Grounds for Patent Invalidity?
Third parties can challenge the validity of a patent on several grounds.
- Prior Art: The most common ground for invalidity is the existence of prior art that anticipates or renders obvious the claimed invention. Prior art includes any published patent, patent application, journal article, or public disclosure that predates the patent's filing date. For RE42353, prior art relevant to antiviral phosphonic acid derivatives would be scrutinized.
- Obviousness: Even if not directly anticipated, the invention might be deemed obvious to a person skilled in the art if the differences between the claimed invention and the prior art are such that the invention as a whole would have been obvious at the time the invention was made.
- Enablement and Written Description: The patent must adequately describe the invention and how to make and use it. If the specification is insufficient, the patent may be invalid.
- Indefiniteness: Claims must be clear and precise. Vague or ambiguous claims can be deemed indefinite.
What is the Impact of Reissue on Validity?
The reissue process itself can be a point of scrutiny for patent validity.
- Correcting Errors: Reissue is intended to correct errors. If the reissue was sought to broaden the claims in a manner not permissible or to cover subject matter that was not originally disclosed, its validity could be challenged.
- Original Intent: Courts may examine whether the reissue claims are consistent with the original invention as intended by the inventors and as supported by the original disclosure.
How does RE42353 Intersect with Other Antiviral Patents?
The patent landscape for antivirals is dense, and RE42353 likely intersects with other patents.
- Freedom to Operate (FTO): Companies developing new antiviral therapies or generic versions of existing ones must conduct FTO analyses to ensure their products do not infringe on existing patents, including RE42353. This involves mapping the claims of RE42353 against their own product and development activities.
- Patent Litigation: The assertion of RE42353 against alleged infringers can lead to patent litigation. The outcome of such litigation depends on claim construction, infringement analysis, and validity challenges.
- Licensing: The assignee of RE42353 may choose to license the patent rights to other companies for a fee or royalty, providing a revenue stream and allowing for broader commercialization or development of related therapies.
Key Takeaways
- United States Patent RE42353 protects specific phosphonic acid derivatives with antiviral activity.
- The patent's scope is defined by its claims, covering chemical structures and methods of treating viral infections.
- As a reissued patent, its validity and term are influenced by the original patent and the reissue process itself.
- The therapeutic application focuses on inhibiting viral replication through mechanisms such as nucleotide analog action.
- The patent landscape is competitive, with numerous entities holding patents in the antiviral phosphonic acid derivative space.
- Freedom to operate, patent term, and potential validity challenges are critical considerations for companies operating in this field.
FAQs
- What specific viruses are targeted by the compounds claimed in RE42353?
The patent claims a broad therapeutic use against viral infections. Specific viruses may be exemplified, but the claims are generally directed to the class of compounds and their general antiviral efficacy rather than a single virus. Historical data for similar compound classes suggests potential activity against viruses like CMV, HSV, and HIV.
- How is the patent term for RE42353 determined?
The patent term is primarily based on the original patent's term, typically 20 years from the earliest non-provisional filing date. The reissue process can affect this, with specific rules governing whether the term is shortened or remains the same, particularly if claims were broadened or narrowed. Regulatory extensions like PTE or PTA may also apply.
- Can generic manufacturers produce drugs covered by RE42353 before its patent expiration?
Generic manufacturers generally cannot produce drugs covered by an active and valid patent until that patent expires. The expiration date of RE42353, considering any extensions, dictates when generic production is permissible without infringement.
- What is the significance of RE42353 being a "reissued" patent?
A reissued patent indicates that the original patent was amended or corrected after its initial grant. This can occur to fix errors, clarify claims, or sometimes to broaden protection. The reissue process itself can be a basis for validity challenges if it is perceived as an improper expansion of patent rights.
- What steps should a company take to assess its freedom to operate regarding RE42353?
A company must conduct a thorough Freedom to Operate (FTO) analysis. This involves a detailed review of the claims in RE42353, comparing them to the company's product or technology, and analyzing relevant prior art and potential validity challenges to ensure no infringement occurs. Consulting with patent counsel specializing in intellectual property and pharmaceuticals is essential.
Citations
[1] United States Patent and Trademark Office. (n.d.). Manual of Patent Examining Procedure (MPEP). Retrieved from USPTO website.
[2] De Clercq, E. (2009). Antiviral drugs: 50 years of discovery and development. Nature Reviews Drug Discovery, 8(2), 135–149.
[3] Herdewijn, P. (2006). Antiviral nucleoside and nucleotide analogues. Methods in Molecular Biology (Clifton, N.J.), 335, 3–31.
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