(rih-TUK-sih-mab) 
A drug used alone or with other drugs under the brand names Riabni, Rituxan, Ruxience, and Truxima to treat certain types of B-cell non-Hodgkin lymphoma, chronic lymphocytic leukemia, and B-cell acute leukemia that are CD20 positive. Rituximab is also being studied in the treatment of other conditions and types of cancer. Rituximab binds to a protein called CD20, which is found on B cells (a type of white blood cell) and some types of cancer cells. This may help the immune system kill cancer cells. Rituximab is a type of monoclonal antibody.