PPMX-T002 targets CDH3, existing on many types of cancer cell surface. Antibody labelled with radioisotope (RI) is used for radioimmunotherapy (RIT). It is designed so that antibodies bind to cancer surface, and then irradiation of RI attacks cancer.
PPMX-T003 targets transferrin receptor (TfR), which is expressed on cell membrane surface for intake of Tf combined with iron. All the cells must take iron into cells to survive. Numerous TfRs are expressed on cancer cells proliferating excessively.
So far, many trials have been made to kill cancer cells by inhibiting iron intake to delete iron from them. As of today, however, no antibody for clinical use has been obtained yet. PPMX-T003, fully human antibody obtained with the phage display method, kills cancer cells effectively through its unprecedentedly high iron intake blocking function.
PPMX-T004 is an antibody drug conjugate (ADC), which is an antibody targeting CDH3 on cancer cell surface bound to drug (anti-cancer drug). When the antibody binds to a cancer cell, it enters inside the cell with the drug, which attacks the cancer cell from inside. Regardless of a patient’s immune conditions, significant efficacy can be expected. We have been assessing the best combination of a drug and a linker to proceed with the development as a new ADC.