Seattle Genetics has exercised an option to co-develop an additional antibody-drug conjugate (ADC) under an existing ADC collaboration agreement with Agensys, an affiliate of Tokyo-based Astellas Pharma. The ADC, called ASG-15ME, targets the tumor antigen SLITRK6, which is expressed on bladder and lung cancer.

ASG-15ME is composed of a fully human antibody directed to SLITRK6, an antigen expressed in multiple solid tumors. Preclinically, ASG-15ME has demonstrated antitumor activity in models of bladder and lung cancer. The antibody is attached to a synthetic cytotoxic agent, monomethyl auristatin E (MMAE), via an enzyme-cleavable linker using Seattle Genetics' proprietary technology. The ADC is designed to be stable in the bloodstream, but to release MMAE upon internalization into SLITRK6-expressing tumor cells, resulting in targeted cell-killing.

Seattle Genetics will make an option exercise payment and thereafter fund half of the future development costs for the ASG-15ME program.