Factor VIII DNA Cassettes for Repeatable Nonviral Gene Delivery
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Solution Overview
Problem
Current gene therapy methods for treating Hemophilia A face limitations due to the size constraints of viral vectors, immunogenicity, and the need for repeated administration, which are not adequately addressed by existing AAV-based therapies, leading to challenges in achieving durable and effective expression of Factor VIII.
Innovation Solution
The use of biocompatible carriers or lipid nanoparticles containing DNA molecules with engineered inverted repeats and restriction sites for nicking endonucleases to deliver and express Factor VIII, allowing for prolonged and stable expression through multiple doses, thereby overcoming size limitations and immunogenicity issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If viral vectors (AAV) are used to deliver Factor VIII gene, then gene delivery is achieved, but the transgene size is limited to less than 150,000 Da or 4.7 kb
Solution Approach 1:
The patent divides the Factor VIII gene delivery system into multiple AAV vectors (dual- or triple-vector systems), where each vector carries a portion of the transgene. This segmentation allows the large Factor VIII gene to be delivered in manageable fragments that reassemble in the target cell, overcoming the 4.7 kb capacity limit of individual AAV vectors.
Solution Approach 2:
The patent employs nested AAV vector systems where multiple vectors work together in a hierarchical manner. The first vector delivers early replication functions, while subsequent vectors deliver later replication functions and the transgene, creating a nested delivery architecture that progressively assembles the complete therapeutic payload within the target cell.
2Productivity
If viral Rep or Nonstructural Protein 1 Binding Element is included to ensure efficient replication and packaging, then packaging efficiency is improved, but the risk of vector mobilization and genome re-activation increases
Solution Approach 1:
The patent extracts and removes the Rep binding element sequences from the AAV vector constructs. By eliminating these dangerous sequences while retaining the essential packaging and replication functions through alternative means, the patent reduces the risk of vector mobilization and unwanted genome re-activation in patients.
Solution Approach 2:
The patent converts the potential harm of Rep binding elements by using truncated or modified versions that provide necessary packaging functions without the harmful mobilization activity. The harmful sequences are transformed into benign or beneficial elements that maintain vector functionality while eliminating safety risks.
3Ease of operation
If viral particles derived from wild-type viruses are used for gene therapy, then gene delivery is achieved, but pre-existing neutralizing antibodies in patients hinder therapy efficacy
Solution Approach 1:
The patent modifies specific local properties of the AAV capsid by using engineered or serotype-specific variants that evade pre-existing neutralizing antibodies. By altering the surface properties of the viral particle while maintaining its core delivery function, the patent enables gene delivery in patients with pre-existing immunity to common AAV serotypes.
4Ease of operation
If capsids of viral vectors are used for gene delivery, then transgene delivery is achieved, but the capsids are immunogenic preventing re-administration
Solution Approach 1:
The patent employs a platform of multiple AAV serotypes and engineered capsid variants that can be selectively chosen based on patient history. This universal approach allows the same therapeutic payload to be delivered using different capsid 'vehicles' that do not cross-react with previous immune responses, enabling re-administration when needed.
Data Source
AI summary
Provided herein are double strand DNA molecules comprising inverted repeats, expression cassette and one or more restriction sites for nicking endonucleases, the methods of use thereof, and the methods of making therefor.