Inclusion of PF68 Surfactant Improves Stability of rAAV Titer when Passed through a Surgical Device Used in Retinal Gene Therapy

• Main Authors: Maria I. Patrício, Christopher I. Cox, Clare Blue, Alun R. Barnard, Cristina Martinez-Fernandez de la Camara, Robert E. MacLaren
• Format: Article
• Language: English
• Published: Elsevier 2020-06-01
• Series: Molecular Therapy: Methods & Clinical Development
• Subjects: AAV; choroideremia; retinal gene therapy; prenylation; surfactant; biocompatibility
• Online Access: http://www.sciencedirect.com/science/article/pii/S2329050119301305

Recent advances in recombinant adeno-associated virus (rAAV) gene therapy for choroideremia show gene replacement to be a promising approach. It is, however, well known that contact of vector solution with plastic materials in the surgical device may result in non-specific adsorption with resulting loss of physical titer and/or level of protein expression and activity. Here we assessed the biocompatibility and stability of rAAV2-REP1 (Rab Escort Protein-1) before and following passage through the injection device over a period of time to mimic the clinical scenario. Three identical devices were screened using two concentrations of vector: high (1E+12 DNase-resistant particles [DRP]/mL) and low (1E+11 DRP/mL), to mimic high- and low-dose administrations of vector product. The low dose was prepared using either formulation buffer that contained 0.001% of a non-ionic surfactant (PF68) or balanced salt solution (BSS). We observed significant losses in the genomic titer of samples diluted with BSS for all time points. The addition of 0.001% PF68 did not, however, affect rAAV physical titer, or REP1 protein expression and biological activity. Hence we observed that neither the genomic titer nor the biological activity of a rAAV2-REP1-containing solution was affected following passage through the surgical device when PF68 was present as a surfactant and this was maintained over a period up to 10 h.