Obinutuzumab is an antineoplastic CD20 antibody used to treat untreated chronic lymphocytic leukemia in combination with chlorambucil.In contrast to rituximab, which is a classic type I CD20 antibody, obinutuzumab binds to type II CD20 antibodies. This allows obinutuzumab to have a much higher induction of antibody-dependant cytotoxicity and a higher direct cytotoxic effect than the classic CD20 antibodies.