Preclinical Evaluation of a Recombinant Adeno-Associated Virus Vector Expressing Human Alpha-1 Antitrypsin Made Using a Recombinant Herpes Simplex Virus Production Method

Abstract

Recombinant adeno-associated virus (rAAV) vectors offer promise for gene therapy of alpha-1 antitrypsin (AAT) deficiency. A toxicology study in mice evaluated intramuscular injection of an rAAV vector expressing human AAT (rAAV-CB-hAAT) produced using a herpes simplex virus (HSV) complementation system or a plasmid transfection (TFX) method at doses of 3Â10 11 vg (1.2Â10 13 vg/kg) for both vectors and 2Â10 12 vg (8Â10 13 vg/kg) for the HSV-produced vector. The HSV-produced vector had favorable in vitro characteristics in terms of purity, efficiency of transduction, and hAAT expression. There were no significant differences in clinical findings or hematology and clinical chemistry values between test article and control groups and no gross pathology findings. Histopathological examination demonstrated minimal to mild changes in skeletal muscle at the injection site, consisting of focal chronic interstitial inflammation and muscle degeneration, regeneration, and vacuolization, in vector-injected animals. At the 3Â10 11 vg dose, serum hAAT levels were higher with the HSVproduced vector than with the TFX-produced vector. With the higher dose of HSV-produced vector, the increase in serum hAAT levels was dose-proportional in females and greater than dose-proportional in males. Vector copy numbers in blood were highest 24 hr after dosing and declined thereafter, with no detectable copies present 90 days after dosing. Antibodies to hAAT were detected in almost all vector-treated animals, and antibodies to HSV were detected in most animals that received the highest vector dose. These results support continued development of rAAV-CB-hAAT for treatment of AAT deficiency.

Safety and Efficacy Evaluation of rAAV2tYF-PR1.7-hCNGA3 Vector Delivered by Subretinal Injection in CNGA3 Mutant Achromatopsia Sheep

“…22 Concentrations of BHK protein, bovine serum albumin, Benzonase, and AVB ligand were measured by enzyme-linked immunosorbent assay (ELISA) using commercially available kits. HSV and BHK DNA were measured by qPCR.…”

Progress with Recombinant Adeno-Associated Virus Vectors for Gene Therapy of Alpha-1 Antitrypsin Deficiency

“…26,27 The HSV complementation system for vector production was validated in a mouse toxicology study comparing it to the previously used traditional transfection method and found that the HSV vector system had increase packaging efficiency as well as increased in vivo vector expression and a similar safety profile as traditionally produced vector. 28 The phase 2 clinical trial consisted of 3 dose cohorts of rAAV1-CB-hAAT at 6 · 10 11 , 1.9 · 10 12 , or 6 · 10 12 vg/kg, with 3 patients per cohort. The total dose in this study ranged from 3.3 · 10 14 to 4.3 · 10 14 vg per subject.…”

Alpha-1-Antitrypsin Deficiency – Molecular Basis, Clinical Presentation, Therapeutic Options and an Integrative Approach in Diagnostics / DEFICIJENCIJA ALFA-1-ANTITRIPSINA – MOLEKULSKE OSNOVE, KLINIČKE MANIFESTACIJE, TERAPIJSKE MOGUĆNOSTI I INTEGRATIVNI PRISTUP U DIJAGNOSTICI

“…Despite encouraging results in animal models, amended by confirmation in three clinical and one preclinical study (25)(26)(27)(28), its use in the treatment of pulmonary manifestations has not been officially approved yet. Up to now, the efficiency of gene therapy in the prevention of accumulation of »mutated« AAT molecules in hepatocytes has been tested only in animal models, and beside positive results, additional toxic effects have also been revealed (24).…”