Coordinating the in vivo processes for minicircle production - a novel approach to large scale manufacturing

ABSTRACT Safety as well as efficiency issues in connection with bacterial backbone sequences should be carefully considered when designing new DNA vaccines or non-viral gene therapy approaches. Bacterial backbone sequences like antibiotic resistance markers or regulatory bacterial elements constitute biological safety risks and reduce the overall efficiency of the DNA agent. To overcome these problems the minicircle technology has been developed. But, despite all the obvious advantages, minicircles have so far not replaced their problem laden conventional counterpart in gene transfer applications what can be contributed to efficiency issues in large scale manufacturing. In this article we describe the combined efforts of experts in the field of minicircle development, large scale biomanufacturing and downstream process development to provide a new approach. The Recombination Based Plasmid Separation (RBPS) Technology, which has already solved crucial problems associated with minicircle-DNA production, has been developed further for this purpose. A novel parental plasmid exploiting advanced in vivo process coordination for restriction and subsequent degradation of miniplasmid-DNA will be introduced. Furthermore we describe the scale-up of minicircle-DNA production by fermentation in combination with high performance downstream processes including purification by ion exchange and hydrophobic interaction chromatography on monolithic material.