Preclinical Development of an AAV8-hUGT1A1 Vector for the Treatment of Crigler-Najjar Syndrome

Fanny Collaud (1, 2) , Giulia Bortolussi (3) , Laurence Guianvarc'H (1, 2) , Sem Aronson (4) , Thierry Bordet (5) , Philippe Veron (1, 2) , Severine Charles (1, 2) , Patrice Vidal (1, 2) , Marcelo Simon Sola (1, 2) , Stephanie Rundwasser (1, 2) , Delphine Dufour (1, 2) , Florence Lacoste (1, 2) , Cyril Luc (1, 2) , Laetitia Wittenberghe (1, 2) , Samia Martin (1, 2) , Christine Le Bec (1, 2) , Piter Bosma (4) , Andres Muro (3) , Giuseppe Ronzitti (1, 2) , Matthias Hebben (1, 2) , Federico Mingozzi (1, 2)

1 Généthon
2 INTEGRARE - Approches génétiques intégrées et nouvelles thérapies pour les maladies rares
3 Trieste - International Centre for Genetic Engineering and Biotechnology (ICGEB)
4 UvA - University of Amsterdam [Amsterdam] = Universiteit van Amsterdam
5 AFM-Téléthon - Association française contre les myopathies

Adeno-associated viruses (AAVs) are among the most efficient vectors for liver gene therapy. Results obtained in the first hemophilia clinical trials demonstrated the long-term efficacy of this approach in humans, showing efficient targeting of hepatocytes with both self-complementary (sc) and single-stranded (ss) AAV vectors. However, to support clinical development of AAV-based gene therapies, efficient and scalable production processes are needed. In an effort to translate to the clinic an approach of AAV-mediated liver gene transfer to treat Crigler-Najjar (CN) syndrome, we developed an (ss)AAV8 vector carrying the human UDP-glucuronosyltransferase family 1-member A1 (hUGT1A1) transgene under the control of a liver-specific promoter. We compared our construct with similar (sc)AAV8 vectors expressing hUGT1A1, showing comparable potency in vitro and in vivo. Conversely, (ss)AAV8-hUGT1A1 vectors showed superior yields and product homogeneity compared with their (sc) counterpart. We then focused our efforts in the scale-up of a manufacturing process of the clinical product (ss)AAV8-hUGT1A1 based on the triple transfection of HEK293 cells grown in suspension. Large-scale production of this vector had characteristics identical to those of small-scale vectors produced in adherent cells. Preclinical studies in animal models of the disease and a good laboratory practice (GLP) toxicology-biodistribution study were also conducted using large-scale preparations of vectors. These studies demonstrated long-term safety and efficacy of gene transfer with (ss)AAV8-hUGT1A1 in relevant animal models of the disease, thus supporting the clinical translation of this gene therapy approach for the treatment of CN syndrome.

Keywords: long-term safety; liver gene transfer; AAV vector; Crigler-Najjar syndrome; UGT1A1

Domains: Adaptive immunology; Immunology

Fanny Collaud, Giulia Bortolussi, Laurence Guianvarc'H, Sem Aronson, Thierry Bordet, et al.. Preclinical Development of an AAV8-hUGT1A1 Vector for the Treatment of Crigler-Najjar Syndrome. Molecular Therapy - Methods and Clinical Development, 2019, 12, pp.157-174. ⟨10.1016/j.omtm.2018.12.011⟩. ⟨hal-02179298⟩