Pervasive supply of therapeutic lysosomal enzymes in the CNS of normal and Krabbe‐affected non‐human primates by intracerebral lentiviral gene therapy

Abstract

Metachromatic leukodystrophy (MLD) and globoid cell leukodystrophy (GLD or Krabbe disease) are severe neurodegenerative lysosomal storage diseases (LSD) caused by arylsulfatase A (ARSA) and galactosylceramidase (GALC) deficiency, respectively. Our previous studies established lentiviral gene therapy (GT) as a rapid and effective intervention to provide pervasive supply of therapeutic lysosomal enzymes in CNS tissues of MLD and GLD mice. Here, we investigated whether this strategy is similarly effective in juvenile non‐human primates (NHP). To provide proof of principle for tolerability and biological efficacy of the strategy, we established a comprehensive study in normal NHP delivering a clinically relevant lentiviral vector encoding for the human ARSA transgene. Then, we injected a lentiviral vector coding for the human GALC transgene in Krabbe‐affected rhesus macaques, evaluating for the first time the therapeutic potential of lentiviral GT in this unique LSD model. We showed favorable safety profile and consistent pattern of LV transduction and enzyme biodistribution in the two models, supporting the robustness of the proposed GT platform. We documented moderate inflammation at the injection sites, mild immune response to vector particles in few treated animals, no indication of immune response against transgenic products, and no molecular evidence of insertional genotoxicity. Efficient gene transfer in neurons, astrocytes, and oligodendrocytes close to the injection sites resulted in robust production and extensive spreading of transgenic enzymes in the whole CNS and in CSF, leading to supraphysiological ARSA activity in normal NHP and close to physiological GALC activity in the Krabbe NHP, in which biological efficacy was associated with preliminary indication of therapeutic benefit. These results support the rationale for the clinical translation of intracerebral lentiviral GT to address CNS pathology in MLD, GLD, and other neurodegenerative LSD.

Perspective on innovative therapies for globoid cell leukodystrophy

“…genotoxicity (Lattanzi et al, 2010(Lattanzi et al, , 2014. Importantly, the safety, feasibility and potential efficacy of the intracerebral LV GT platform delivering functional lysosomal enzymes in the CNS of normal and Krabbe's-affected NHPs has been recently evaluated (Meneghini et al, 2016), and strongly supports the rationale for its clinical development.…”

“…Canine and nonhuman primate models of GLD presenting pathological signs consistent with the human disease are also available (Wenger, 2000). Although the use of these large animal models poses obvious issues in terms of sample size and experimental protocols, the complexity of their brain structures, their longevity, and their genetic diversity, will be of paramount importance for the evaluation of safety and efficacy of candidate innovative therapies before clinical translation (Hemsley and Hopwood, 2010;Meneghini et al, 2016).…”

Harnessing the Potential of Stem Cells for Disease Modeling: Progress and Promises

“…The safety and efficacy of these strategies may be evaluated in engineered stem cell models, that are suitable for the treatment validation and for the screening of potential mutational insertions caused by the integration of the target gene in the host DNA [92][93][94][95]. Thus, even if the use of animal models is still essential before these treatments reach the clinical phase, stem cells are an alternative models enable to test the effectiveness of treatments in a highly efficient, reproducible and fast manner [84][85][86]90,91,96]. For instance, in Adenosine Deaminase Activity (ADA-SCID) immunodeficiency therapy (Strimvelis, GlaxoSmithKline (GSK), approved by EMA in 2016 [97]) ADA-genetically engineered hematopoietic stem cells served as basic cell model for validating the effectiveness of the gene delivery procedure and ultimately were used as therapeutic vehicle in vivo [97].…”

Human iPSC-based neurodevelopmental models of globoid cell leukodystrophy uncover patient- and cell type-specific disease phenotypes

“…However, it fails to fully correct the severe CNS pathology, even if performed at the asymptomatic stage (Allewelt et al, 2016), likely because of the insufficient GALC supply provided by HSPC-derived microglia in the brain and/or modest metabolic correction of endogenous cells. In vivo and ex vivo gene therapy (GT) approaches using lentiviral vectors (LV) and adeno-associated vectors (AAV) benefit GLD animal models (Bradbury et al, 2018;Gentner et al, 2010;Lattanzi et al, 2010Lattanzi et al, , 2014Lin et al, 2005;Meneghini et al, 2016;Rafi et al, 2015;Ricca et al, 2015;Ungari et al, 2015). The advantage of ex vivo GT with LV-modified HSPCs in infants affected by metachromatic leukodystrophy (MLD) -a similar LSD (Biffi et al, 2013;Sessa et al, 2016), suggests that a similar approach might be translated to GLD.…”