Enhancing the potency of in vivo lentiviral vector mediated gene therapy to hepatocytes.

In vivo gene therapy to the liver using lentiviral vectors (LV) may represent a one-and-done therapeutic approach for monogenic diseases. Increasing LV gene therapy potency is crucial for reducing the effective doses, thus alleviating dose-dependent toxicities and facilitating manufacturing. LV-mediated liver transduction may be enhanced by positively selecting LV-transduced hepatocytes after treatment (a posteriori) or by augmenting the initial fraction of LV-targeted hepatocytes (a priori). We show here that the a posteriori enhancement increased transgene output without expansion of hepatocytes bearing LV genomic integrations near cancer genes, in mouse models of hemophilia, an inherited coagulation disorder. Furthermore, we enhanced hepatocyte transduction a priori in mice by transiently inhibiting antiviral pathways and/or through a fasting regimen. The most promising transduction-enhancer combination synergized with phagocytosis-shielded LV, resulting in a remarkable 40-fold increase in transgene output. Overall, our work highlights the potential of minimally invasive, cost-effective treatments capable of improving the potency of in vivo LV gene therapy to hepatocytes, in order to expand its applicability and ease clinical translation.