The pAVEway platform, which will be showcased at the BIO 2007 convention in Boston, US this month, consists of a range of novel vectors for the expression of soluble, secreted or insoluble proteins, corresponding host strains including E. coli and Pseudomonas, and optimised fermentation processes. The system can achieve expression levels of more than 10g/L for a variety of recombinant proteins such as interferon-alpha 2, tumour necrosis factor-alpha and erythropoietin, Avecia says. It puts this down to two "unique" features. Firstly, the basic expression levels can be fully suppressed, so that no protein is produced before induction. "This allows high expression levels even for proteins that would normally impair the growth of the host cells", the company comments. The other key feature is the pAVEway technology's ability to modulate expression levels by varying the inducer concentration. In this way, Avecia explains, the expression kinetics can be tightly regulated to match the folding capabilities of the host cell, enabling the system to express proteins of pronounced folding complexity. Achieving high levels of protein during fermentation is often a bottleneck in the development of efficient production processes, the company says. The choice of expression system, host strain and fermentation conditions has "a profound effect" on the overall quantity and quality of protein generated. It therefore has a major bearing on the success of scale-up from research and development to large-scale good manufacturing practice (GMP) production - and ultimately on the cost of goods, Avecia adds. According to Dr Mark Carver, chief scientific officer for the Avecia Biologics business, pAVEway offers "maximum flexibility when making the critical decision on the choice of expression system", as well as "significant benefits in reducing process development times and costs whilst achieving high titre and quality". Using E. coli as a host, the system can achieve titres of more than 12g/L within one month of receiving the gene of interest, Carver told in-PharmaTechnologist.com. Significantly higher titres are achievable once the initial evaluation process is completed, he said.