Details

Autor(en) / Beteiligte

• Ismail, Ashrafali Mohamed
• Witt, Evan
• Bouwman, Taren
• Clark, Wyatt
• Yates, Bridget
• Franco, Matteo
• Fong, Sylvia

Titel

The longitudinal kinetics of AAV5 vector integration profiles and evaluation of clonal expansion in mice

Ist Teil von

• Molecular therapy. Methods & clinical development, 2024-09, Vol.32 (3), p.101294, Article 101294

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2024

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Adeno-associated virus (AAV)-based vectors are used clinically for gene transfer and persist as extrachromosomal episomes. A small fraction of vector genomes integrate into the host genome, but the theoretical risk of tumorigenesis depends on vector regulatory features. A mouse model was used to investigate integration profiles of an AAV serotype 5 (AAV5) vector produced using Sf and HEK293 cells that mimic key features of valoctocogene roxaparvovec (AAV5-hFVIII-SQ), a gene therapy for severe hemophilia A. The majority (95%) of vector genome reads were derived from episomes, and mean (± standard deviation) integration frequency was 2.70 ± 1.26 and 1.79 ± 0.86 integrations per 1,000 cells for Sf- and HEK293-produced vector. Longitudinal integration analysis suggested integrations occur primarily within 1 week, at low frequency, and their abundance was stable over time. Integration profiles were polyclonal and randomly distributed. No major differences in integration profiles were observed for either vector production platform, and no integrations were associated with clonal expansion. Integrations were enriched near transcription start sites of genes highly expressed in the liver (p = 1 × 10−4) and less enriched for genes of lower expression. We found no evidence of tumorigenesis or fibrosis caused by the vector integrations. [Display omitted] Ismail and colleagues assessed the safety of an AAV5 vector-based gene therapy for >1 year in mice. They found AAV5 vectors have low integration rates in liver, with most integrations detected by ≤2 sequence reads. The integrations were polyclonal in nature, and no evidence of clonal expansion was observed.