HBV RNAi Agents with 3' End Caps for Sustained Virologic Response
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Solution Overview
Problem
Current treatments for Hepatitis B Virus (HBV) are inadequate as they cannot eradicate the intrahepatic HBV covalently closed circular DNA pool or limit the transcription and secretion of HBsAg, leading to life-long therapy and potential virological relapse, with adverse side-effects and drug-resistant variants.
Innovation Solution
Development of RNAi agents comprising specific sequences and formats, such as 18-mer strands with phosphate or modified internucleoside linkers and 3′ end caps, designed to target HBV, forming blunt-ended duplexes to mediate RNA interference and potentially enhance sustained virologic response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current nucleoside/nucleotide inhibitors are used to treat HBV, then viral replication is suppressed, but the intrahepatic cccDNA pool cannot be eradicated and drug-resistant variants emerge
Solution Approach 1:
The patent uses RNA interference technology as an intermediary mechanism to target and silence HBV gene expression. The small interfering RNA (siRNA) molecules act as mediators that specifically bind to HBV mRNA, preventing translation and reducing viral protein production without directly confronting the cccDNA reservoir, thereby avoiding selection pressure for drug resistance
Solution Approach 2:
The invention changes the therapeutic parameter from direct viral DNA inhibition (nucleoside/nucleotide analogs) to post-transcriptional gene silencing (RNA interference). This parameter shift allows the treatment to target viral RNA transcripts and proteins, achieving sustained virologic response through a different molecular mechanism that does not select for traditional drug-resistant variants
2Reliability
If current HBV treatments are administered long-term, then viral load is controlled, but adverse side-effects accumulate and quality of life deteriorates
Solution Approach 1:
The patent employs short-lived siRNA molecules that are designed to be transient and degrade naturally after performing their function. These disposable RNA therapeutics provide temporary but effective gene silencing, reducing the need for indefinite treatment and minimizing cumulative side-effects associated with long-term nucleoside analog use
Solution Approach 2:
The invention implements periodic administration of siRNA therapeutics rather than continuous treatment. The periodic dosing schedule allows the short-lived RNA molecules to exert their effect, then degrade, and be replenished in subsequent cycles, maintaining viral control while reducing cumulative toxicity and improving quality of life
3Quantity of substance
If current therapies focus on reducing viremia, then viral load decreases, but HBsAg secretion continues and immune response remains suppressed
Solution Approach 1:
The patent extracts and specifically targets the HBsAg gene expression pathway using siRNA molecules designed to silence HBsAg mRNA. By selectively removing the translation of HBsAg proteins while allowing other viral functions to proceed, the treatment reduces HBsAg secretion levels, thereby relieving immune suppression and enabling host immune response activation without completely eliminating viral replication
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
These RNAi agents demonstrate improved RNA interference activity, increased duration of effect, and reduced off-target effects, offering a novel approach to treat HBV by targeting HBV RNA, potentially leading to a meaningful clinical cure.
Implementation Method 1
designed to target HBV, forming blunt-ended duplexes to mediate RNA interference
Data Source
AI summary
The disclosure relates to compositions comprising a HBV RNAi agent. In some embodiments, the HBV RNAi agent comprises a sense and an anti-sense strand, each strand being an 18-mer and the strands together forming a blunt-ended duplex, wherein the 3′ end of at least one strand terminates in a phosphate or modified internucleoside linker and further comprises, in 5′ to 3′ order: a spacer; a second phosphate or modified internucleoside linker; and a 3′ end cap. In some embodiments, the 3′ end of both the sense and anti-sense strand further comprise, in 5′ to 3′ order: a spacer; a second phosphate or modified internucleoside linker; and a 3′ end cap. The two strands can have the same or different spacers, phosphates or modified internucleoside linkers, and/or 3′ end caps. The strands can be ribonucleotides, or, optionally, one or more nucleotide can be modified or substituted. Optionally, at least one nucleotide comprises a modified internucleoside linker. Optionally, the RNAi agent can be modified on one or both 5′ end. Optionally, the sense strand can comprise a 5′ end cap which reduces the amount of the RNA interference mediated by this strand. Optionally, the RNAi agent is attached to a ligand. This format can be used to devise RNAi agents to a variety of different targets and sequences. The disclosure also relates to processes for making such compositions, and methods and uses of such compositions, e.g., to mediate RNA interference. The disclosure also pertains to methods of treating, ameliorating and preventing HBV in a patient involving the step of administering to the patient a therapeutic amount of a HBV RNAi agent.