2′-Fluoro-6′-Methylene Carbocyclic Nucleosides for Resistant HBV
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Solution Overview
Problem
Current antiviral therapies for Hepatitis B virus (HBV) face challenges with drug resistance, particularly with nucleoside/nucleotide analogs like lamivudine and adefovir, leading to viral relapse and liver complications due to their inability to effectively target covalently closed circular DNA, necessitating long-term treatment and resulting in resistance mutations.
Innovation Solution
Development of 2′-Fluoro-6′-methylene carbocyclic nucleosides that are active against both wild-type HBV and drug-resistant mutants, including lamivudine and adefovir-resistant strains, offering a new approach to antiviral therapy by potentially reducing the emergence of resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current nucleoside/nucleotide analogs (lamivudine, adefovir) are used for long-term HBV treatment, then viral replication is suppressed, but drug-resistant mutants emerge leading to treatment failure
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of nucleoside analogs through fluorine substitution at the 2′ position and methylene group addition at the 6′ position. These structural parameter changes create new compounds (2′-fluoro-6′-methylene carbocyclic nucleosides) that maintain antiviral activity while overcoming resistance to existing drugs like lamivudine and adefovir, thereby resolving the contradiction between maintaining efficacy and preventing resistance
Solution Approach 2:
The invention creates composite chemical structures by combining fluorinated carbocyclic sugar moieties with nucleobases. This composite approach generates novel nucleoside analogs that possess properties of both the fluorinated sugar component (enhanced stability and resistance to phosphorylation by resistant polymerases) and the nucleobase component (ability to incorporate into viral DNA and terminate replication), thus achieving both sustained efficacy and resistance prevention
2Productivity
If long-term nucleoside/nucleotide treatment is administered, then viral DNA replication is suppressed, but the inability to target cccDNA leads to viral relapse upon discontinuation
Solution Approach 1:
The patent applies preliminary action by designing nucleoside analogs with enhanced pharmacokinetic properties and improved cellular penetration capabilities. The 2′-fluoro-6′-methylene carbocyclic structure is engineered to accumulate in liver cells and potentially target cccDNA reservoirs before discontinuation, thereby preventing viral relapse. This preliminary accumulation and targeting action addresses the limitation of existing drugs that cannot effectively target cccDNA
3Reliability
If existing nucleoside analogs are used, then HBV DNA replication is inhibited, but frequent resistance mutations (e.g., rtL180M±rtM204V/I) compromise treatment effectiveness
Solution Approach 1:
The patent modifies key chemical parameters of nucleoside analogs by introducing fluorine atoms and methylene groups, which alter the molecular properties such as bond strength, metabolic stability, and affinity for viral polymerase. These parameter changes result in compounds that are not recognized by resistance-conferring mutations, thereby maintaining treatment effectiveness without the high resistance rates seen with existing drugs
Data Source
AI summary
The present invention relates to 2′-Fluoro-6′-methylene carbocyclic nucleosides, pharmaceutical compositions containing these nucleosides and their use in the treatment or prophylaxis of a number of viral infections and secondary disease states and conditions thereof, especially including Hepatitis B virus (HBV) and secondary disease states and conditions thereof (cirrhosis and liver cancer), Hepatitis C virus (HCV), Herpes Simplex virus I and II (HSV-1 and HSV-2), cytomegalovirus (CMV), Varicella-Zoster Virus (VZV) and Epstein Barr virus (EBV) and secondary cancers which occur thereof (lymphoma, nasopharyngeal cancer, including drug resistant (especially including lamivudine and/or adefovir resistant) and other mutant forms of these viruses.