Toxicology study assessing efficacy and safety of repeated administration of lipid/DNA complexes to mouse lung

Abstract

For gene therapy to improve lung function in cystic fibrosis (CF) subjects, repeated administration of the gene transfer agent over the lifetime of patients is likely to be necessary. This requirement limits the utility of adenoviral and adeno-associated viral vectors (both previously evaluated in CF gene therapy trials) because of induced adaptive immune responses that render repeated dosing ineffective. For CF gene therapy trials, non-viral vectors are currently the only viable option. We previously showed that the cationic lipid formulation GL67A is the most efficient of several non-viral vectors analysed for airway gene transfer. Here, we assessed the efficacy and safety of administering 12 inhaled doses of GL67A complexed with pGM169, a CpG-free plasmid encoding human CFTR complementary DNA, into mice. We show that repeated administration of pGM169/GL67A to murine lungs is feasible, safe and achieves reproducible, dose-related and persistent gene expression (>140 days after each dose) using an aerosol generated by a clinically relevant nebuliser. This study supports progression into the first non-viral multidose lung trial in CF patients.

Efficient in vivo transfection and safety profile of a CpG-free and codon optimized luciferase plasmid using a cationic lipophosphoramidate in a multiple intravenous administration procedure

“…The long-term expression of pGM144 plasmid in the lungs was in agreement with the previous reports obtained after nebulization of lipidic and polymeric formulations [11,12,35]. Nonetheless, the period of transgene expression was longer after nebulization, lasting more than 4 months [35].…”

“…Nonetheless, the period of transgene expression was longer after nebulization, lasting more than 4 months [35]. Beyond the less sensitivity of BLI technique compared to quantitative PCR and quantitative reverse transcriptase PCR, many hypotheses can be suggested to explain the luc expression difference in term of expression.…”

Electroporation-Mediated Gene Delivery of Na+,K+-ATPase, and ENaC Subunits to the Lung Attenuates Acute Respiratory Distress Syndrome in a Two-Hit Porcine Model

“…For example, cell damage and inflammation are frequently observed when viruses, even those deemed safe such as gutted adenovirus, are used for delivery. In contrast to viral vectors, non-viral vectors generate very little immune response or inflammation in the lung, either as naked plasmid or when complexed with liposomes or other polymers, allowing for multiple vector administrations (25). Unfortunately, the efficiency of gene transfer of many non-viral vectors (including liposomes and nanoparticles) to the airways and alveoli in the lung has been low or even undetectable in human trials (26, 27).…”

Genetic medicines for CF: Hype versus reality

“…The first generation plasmid (termed pGM169) was improved by removing the CpG islands, codon‐optimizing the CFTR cDNA and incorporation of the novel regulatory element, hCEFI, consisting of the elongation factor 1α promoter coupled to the human CMV enhancer Regulatory‐compliant multi‐dose toxicology studies in mice and sheep supporting progression into a multi‐dose clinical trial were undertaken. Interestingly, repeated aerosolization of pGM169/GL67A to mice led to cumulative dose‐related expression on repeat dosing, reaching 94 ± 19% of endogenous murine Cftr levels after 12 deliveries.…”

“…(B) Patients with more severe lung function at start of treatment (Baseline FEV 1 = 50–70%), (C) Patients with less severe lung function at start of treatment (Baseline FEV 1 = 70–90%). The figure is adapted from Ref . as part of a CCBY license.…”