L'innovation

The invention relates to constructs, vectors, relative host cells and pharmaceutical compositions which allow an effective gene therapy, in particular of genes larger than 5Kb by using an improved hybrid dual recombinant AAV vector system.

Adeno-associated virus (AAV) is a small virus which infects humans and some other primate species. While AAV-mediated gene therapy is effective in animal models and in patients with inherited blinding conditions, its application to diseases affecting the retina and requiring a transfer of genes larger than 5kb (referred to as large genes) is inhibited by AAV limited cargo capacity. To overcome this, various AAV-based strategies for large gene transduction have been developed including AAV Oversize (OZ) vectors and dual AAV strategies such as dual AAV overlapping (OV), AAV trans-splicing (TS) and AAV hybrid (with recombinogenic sequences AP or AK) vector systems.

The new dual construct comprising the recombinogenic region AP overcomes the previously described problems encountered with dual AAV hybrid AP, such dimeric construct leading to an optimal expression of the full-length transcripts in retinal cells, subsequently to the recombinaison/transcription/splicing process occurring with hybrid dual AAV vector system.

Accordingly, we observed a significant improvement in full-length ABCA4 mRNA production in retinal cells based on said improved dual AAV hybrid AP system comprising this newly-designed dual construct composed a pair of nucleic acid sequences: