HLP2-TI-codop-FIX Expression Cassette for Hemophilia B Gene Therapy
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Solution Overview
Problem
Current gene therapy approaches for haemophilia B using adeno-associated viral vectors face challenges such as immune responses leading to liver inflammation and require high vector doses, limiting their safety and efficacy.
Innovation Solution
Development of a new AAV expression cassette, HLP2-TI-codop-FIX, which includes a single-stranded vector design, a modified liver-specific promoter, a truncated intron, and codon-optimized FIX sequence, enhancing expression levels and safety by allowing more efficient packaging and higher transgene expression with lower vector doses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high dose AAV vectors are used to achieve therapeutic FIX expression, then FIX expression levels are improved, but immune response and liver inflammation worsen
Solution Approach 1:
The patent modifies multiple parameters of the AAV vector system including promoter strength (using HLP2 instead of LP1), intron length (truncating intron 1A from 6.2kb to 299bp), and codon optimization to enhance FIX expression efficiency. These parameter changes enable achieving therapeutic FIX levels at lower vector doses, thereby reducing immune response and liver inflammation while maintaining effective treatment.
2Quantity of substance
If self-complementary AAV vectors are used, then transgene expression is achieved, but vector packaging efficiency and dose requirements worsen
Solution Approach 1:
The patent inverts the conventional approach by using a single-stranded AAV vector design instead of self-complementary vectors. This inversion allows for more efficient packaging and higher transgene expression per vector particle, reducing the dose required and improving overall productivity while maintaining therapeutic effect.
Solution Approach 2:
The patent extracts and removes the intron 1A sequence from the AAV vector payload, reducing the total vector size from 6.2kb to 299bp. This extraction improves packaging efficiency and allows for higher expression per vector unit, addressing the productivity issue while maintaining transgene expression.
3Quantity of substance
If wild type FIX sequence is used in the vector, then gene transfer is achieved, but transgene expression level worsens
Solution Approach 1:
The patent applies codon optimization to the FIX sequence, changing the codon usage pattern to match human liver cell preferences. This parameter change increases transgene expression levels by improving translation efficiency while maintaining the same basic vector construction approach, thus enhancing expression without significantly complicating manufacturing.
Data Source
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AI summary
The invention relates to a new, more potent, coagulation factor IX (FIX) expression cassette for gene therapy of haemophilia B (HB). Disclosed is a vector for expressing factor IX protein, the vector comprising a promoter, a nucleotide sequence encoding for a functional factor IX protein and an intron sequence, wherein the intron sequence is positioned between exon 1 and exon 2 of the nucleotide sequence encoding for a functional factor IX protein, and wherein the intron sequence has at least 80% identity to the sequence of SEQ ID NO. 1 as disclosed herein.