ACS BIOT 2016: San Diego

Cardiovascular diseases (CVD) have been leading cause of morbidity and mortality in Indian subcontinent and Myocardial Infraction is one of the major reason for this mortality. Currently, ST elevated myocardial infraction is medically managed by the various fibrinolytic agents which include enzymes like streptokinase and activation factors like tPA. Both Streptokinase and tPA have their own strengths ad limitations, with only marginal reported difference in mortality, there is a 10 fold difference in cost, bearing substantial impact of their usage in the subcontinent. Owning to its lower price compared to the expensive tPA, for a large majority of patients especially in the developing countries, affordable clot-buster therapy with streptokinase still remained elusive. Thus, emerged a dire need to develop a process to produce this protein more efficiently through a recombinant expression host making it even more affordable. Recombinant Streptokinase (rSK) was developed from in-vitro to animal and to clinical studies in patients with AMI. This rSK product expressed by a non-streptococcal bacterial organism has a dramatic effect on major disadvantageous features of the earlier version of SK, namely the induction of an antigenic response and of acute nonspecific febrile and hypotensive side effects.

Further improvement of a Recombinant version of streptokinase has been achieved by replacing the Ampicillin (Beta-Lactum) marker with a Kanamycin one. The half life of Kanamycin being higher than Ampicillin helps in plasmid stability and yields are higher. This feature also makes the clones more stable in terms of expression. The effective concentration needed is lesser than Ampicillin and owing to its better stability during fermentation it is added only once during the process that reduces the production costs. Kanamycin has also been found to be less sticky and gets removed during the downstream process. Thus, its contamination in the final product is much lesser than Ampicillin, which, eases the regulatory hurdles like allergenicity and immunogenicity further reducing cost. Also process related impurities are much less in the kana process. It has been shown using the Kana clone in High Cell density fermentation; protein expression levels can be more than 700mg/L, making this life saving therapeutic protein more affordable for the masses, potentially saving millions of lives.