Summit Therapeutics plc is a biopharmaceutical company, which is engaged in drug development. The Company is focused on the discovery, development and commercialization of medicines for indications for which there are no existing or only inadequate therapies. It is conducting clinical programs focused on the infectious disease Clostridium difficile infection (CDI). Its lead CDI product candidate is ridinilazole, which is an orally administered small molecule antibiotic. Its Ridinilazole is in Phase II clinical trials. It has conducted over three Phase I clinical trials of ezutromid.