Intravenous infusion of AAV8.TBG.hLDLR was well tolerated in rhesus macaques, associated with only mild liver histopathology and transient transaminase elevations.
Does AAV8.TBG.hLDLR gene therapy cause toxicity in wild-type and LDLR+/- rhesus macaques?
AAV8.TBG.hLDLR gene therapy demonstrated an acceptable safety profile in rhesus macaques, supporting its progression to Phase 1 clinical trials for homozygous familial hypercholesterolemia.
Vectors based on adeno-associated virus serotype 8 (AAV8) have been evaluated in several clinical trials of gene therapy for hemophilia B with encouraging results. In preparation for a Phase 1 clinical trial of AAV8 gene therapy for the treatment of homozygous familial hypercholesterolemia (HoFH), the safety of the clinical candidate vector, AAV8.TBG.hLDLR, was evaluated in wild-type rhesus macaques and macaques heterozygous for a nonsense mutation in the low-density lipoprotein receptor (LDLR) gene (LDLR+/−). Intravenous infusion of 1.25 × 1013 GC/kg of AAV8.TBG.hLDLR expressing the human version of LDLR was well tolerated and associated with only mild histopathology that was restricted to the liver and sporadic, low-level, and transient elevations in transaminases. Some animals developed T cells to both capsid and the hLDLR transgene, although these adaptive immune responses were most evident at the early time points from peripheral blood and in mononuclear cells derived from the liver. This toxicology study supports the safety of AAV8.TBG.hLDLR for evaluation in HoFH patients, and provides some context for evaluating previously conducted clinical trials of AAV8 in patients with hemophilia.
Greig et al. (2017) studied Homozygous familial hypercholesterolemia (HoFH). AAV8.TBG.hLDLR was evaluated on Safety and toxicity (histopathology, transaminases, immune response). Intravenous infusion of AAV8.TBG.hLDLR was well tolerated in rhesus macaques, associated with only mild liver histopathology and transient transaminase elevations.