Evaluation of tolerance to lentiviral LV-RPE65 gene therapy vector after subretinal delivery in non-human primates

Transl Res. 2017 Oct;188:40-57.e4. doi: 10.1016/j.trsl.2017.06.012. Epub 2017 Jul 8.

Abstract

Several approaches have been developed for gene therapy in RPE65-related Leber congenital amaurosis. To date, strategies that have reached the clinical stages rely on adeno-associated viral vectors and two of them documented limited long-term effect. We have developed a lentiviral-based strategy of RPE65 gene transfer that efficiently restored protein expression and cone function in RPE65-deficient mice. In this study, we evaluated the ocular and systemic tolerances of this lentiviral-based therapy (LV-RPE65) on healthy nonhuman primates (NHPs), without adjuvant systemic anti-inflammatory prophylaxis. For the first time, we describe the early kinetics of retinal detachment at 2, 4, and 7 days after subretinal injection using multimodal imaging in 5 NHPs. We revealed prolonged reattachment times in LV-RPE65-injected eyes compared to vehicle-injected eyes. Low- (n = 2) and high-dose (n = 2) LV-RPE65-injected eyes presented a reduction of the outer nuclear and photoreceptor outer segment layer thickness in the macula, that was more pronounced than in vehicle-injected eyes (n = 4). All LV-RPE65-injected eyes showed an initial perivascular reaction that resolved spontaneously within 14 days. Despite foveal structural changes, full-field electroretinography indicated that the overall retinal function was preserved over time and immunohistochemistry identified no difference in glial, microglial, or leucocyte ocular activation between low-dose, high-dose, and vehicle-injected eyes. Moreover, LV-RPE65-injected animals did not show signs of vector shedding or extraocular targeting, confirming the safe ocular restriction of the vector. Our results evidence a limited ocular tolerance to LV-RPE65 after subretinal injection without adjuvant anti-inflammatory prophylaxis, with complications linked to this route of administration necessitating to block this transient inflammatory event.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Eye Proteins / administration & dosage*
  • Female
  • Gene Transfer Techniques*
  • Genetic Vectors / administration & dosage*
  • Genetic Vectors / adverse effects*
  • Lentivirus / genetics*
  • Macaca fascicularis
  • Receptors, G-Protein-Coupled / administration & dosage*
  • Retina

Substances

  • Eye Proteins
  • G protein-coupled receptor RGR
  • Receptors, G-Protein-Coupled