Recombinant AAV integration profiles in non-human primates and gene therapy participants after treatment with valoctocogene roxaparvovec

Recombinant adeno-associated viruses (AAVs) are clinically relevant vectors for gene therapy that persist largely as extrachromosomal episomes but also infrequently integrate into host genomes. Valoctocogene roxaparvovec is an approved AAV-based gene therapy for severe hemophilia A. We present a molecular characterization of the vector integration profiles in 5 human biopsy samples from valoctocogene roxaparvovec clinical trials as well as in samples from valoctocogene roxaparvovec- treated non-human primates (NHPs). The number of genomic integrations was substantially below the number of transgene-expressing cells, and integration profiles were similar between human and NHP samples. The integration profiles were polyclonal, similarly distributed across the genome, and demonstrated a small bias toward regions of open chromatin and actively transcribed genes, with no relative enrichment in cancer-associated genes. These observations were replicated between species and support the concept that preclinical assessment of AAV vector integration in NHPs is representative of outcomes in humans.