Codon-Altered Factor VIII Variants for Gene Therapy
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Solution Overview
Problem
Current treatments for hemophilia A, such as Factor VIII replacement therapy, are costly, require frequent administration, and can lead to the formation of inhibitor antibodies, while gene therapy faces challenges due to the large size of the Factor VIII coding sequence and poor expression of B-domain deleted variants.
Innovation Solution
Development of codon-altered Factor VIII variants with high sequence identity to specific nucleotide sequences, including CS01, CS04, and CS23, which replace the native B-domain with a linker sequence and include furin cleavage sites, enhancing packaging and delivery via gene therapy vectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional Factor VIII replacement therapy is used, then Factor VIII activity is provided to treat hemophilia A, but the treatment requires frequent administration every second or third day due to short half-life, placing a burden on patient compliance
Solution Approach 1:
The patent applies parameter changes by modifying the Factor VIII protein structure through codon alteration and B-domain deletion to create variants with extended half-life. The codon-altered sequences (CS01, CS04, CS23) and linker replacements transform the original Factor VIII into a variant that maintains activity while prolonging persistence in vivo, thereby reducing administration frequency and improving patient compliance
2Reliability
If the full-length wild-type Factor VIII coding sequence is used for gene therapy, then complete Factor VIII activity is encoded, but the sequence is too large (7053 base pairs) to be packaged in conventional AAV gene therapy vectors
Solution Approach 1:
The patent extracts and removes the B-domain from the Factor VIII coding sequence, creating a B-domain deleted variant. This extraction reduces the overall size of the coding sequence while preserving the essential A and C domains that are responsible for Factor VIII's coagulation activity, making it compatible with AAV vector packaging constraints
Solution Approach 2:
The patent segments the Factor VIII protein structure by dividing it into functional domains (A-domain, B-domain, C-domain) and selectively retaining only the essential A and C domains while removing the B-domain. This segmentation allows the coding sequence to fit within viral vector constraints while maintaining biological function
3Volume of stationary object
If B-domain deleted variants of Factor VIII are used for gene therapy, then the coding sequence size is reduced for vector packaging, but expression of these variants has been poor
Solution Approach 1:
The patent applies parameter changes at the nucleotide level by altering codon usage in the B-domain deleted Factor VIII sequence. The codon-altered sequences (CS01, CS04, CS23) optimize translation efficiency and protein expression levels, transforming the poorly expressed B-domain deleted variant into a high-expression construct suitable for gene therapy
4Reliability
If Factor VIII replacement therapy is administered continuously, then Factor VIII activity is maintained to prevent bleeding episodes, but the treatment is expensive and requires strict lifelong compliance
Solution Approach 1:
The patent enables self-service by implementing gene therapy that allows the patient's own cells to produce Factor VIII autonomously. The codon-altered, B-domain deleted Factor VIII variant is delivered via AAV vector, integrating into the patient's genome and enabling continuous, self-sustaining production of functional Factor VIII, eliminating the need for external administration and compliance monitoring
Data Source
AI summary
The present disclosure provides, among other aspects, codon-altered polynucleotides encoding Factor VIII variants for expression in mammalian cells. In some embodiments, the disclosure also provides mammalian gene therapy vectors and methods for treating hemophilia A.