Novel enzymatic site-specific antibody drug conjugation technique to produce homogeneous antibody drug conjugate (ADC)s with improved safety, stability and efficacy

The goal of this project is to validate a novel enzymatic site specific conjugation technique to develop antibody drug conjugate ADC s with better safety profile wider therapeutic window and higher potency ADCs that combine the target specificity of an antibody with the potent cell killing ability of a cytotoxic drug have shown considerable promise in cancer treatment However major improvements in ADC production is required as existing methods produce a heterogeneous mixture of ADCs with different number of drugs attached to different locations on the antibody Each subpopulation of ADCs in such heterogeneous mixtures exhibit different pharmacokinetics safety and efficacy profiles and limit the exploitation of their full therapeutic potential Conjugation of drugs to specific sites on antibodies is currently being investigated to generate homogeneous ADCs However the methods that are currently explored require antibodies to be modified through point mutation for direct chemical conjugation or engineered tags for enzymatic conjugation These procedures are complicated and time consuming In addition these mutations may affect antibody stability and introduce immunogenicity To overcome these limitations we have developed a technology to site specifically conjugate cytotoxic drugs to intact antibodies by employing engineered microbial transglutaminase mTgase A major advantage of our technology is that it allows us to generate homogeneous ADCs without the need to make any modifications to antibody structure Our preliminary results demonstrate that engineered mTgase can catalyze site specific conjugation of drugs to native unmodified IgGs The first ADC to be generated using our mTgase mediated conjugation approach will be an anti HER IgG ADC that will be used to treat HER overexpressing tumors In preliminary studies a panel of site specific anti HER ADCs produced by our approach exhibited better stability and efficacy both in vitro and in vivo In phase I studies we will compare the stability pharmacokinetics and anti tumor efficacy of different site specific anti HER ADCs that we have generated in HER expressing tumor models to identify the most promising ADC candidate In Phase II studies we will perform the preclinical evaluation of our lead ADC candidate to enable IND filing and further clinical trials We believe that the successful completion of these studies will transform the ADC field and will substantially cut down the cost and time required for ADC production The proposal aims to validate a novel enzymatic site specific antibody drug conjugation technique to produce homogeneous antibody drug conjugate ADC s with better safety stability and efficacy ADCs that are currently in market or in clinical trials are produced as heterogeneous mixtures of different ADC species with varying stability toxicity and efficacy profiles Our engineered microbial transglutaminase mediated conjugation technique will provide a rapid and highly efficient method to generate stable homogeneous ADCs with high potency Because this technique allows conjugation of toxins to the heavy chain constant region of intact IgG our approach will drastically reduce the cost and time required for ADC production