Rituxan is a CD20-directed cytolytic antibody.
Rituxan is specifically indicated for use in combination with fludarabine and cyclophosphamide (FC), for the treatment of adult patients with previously untreated and previously treated CD20-positive chronic lymphocytic leukemia (CLL).
Rituxan is supplied as an injection for intravenous administration. The recommended dose of Rituxan for CLL is 375 mg/m2 the day prior to the initiation of FC chemotherapy, then 500 mg/m2 on Day 1 of cycles 2-6 (every 28 days).
The FDA approval of Rituxan for CLL was based on two phase III studies. In the CLL8 study of 817 previously untreated patients, the addition of rituximab to FC yielded a 79% improvement in progression-free survival. The duration of progression-free survival was extended by more than 8 months compared with FC alone (39.8 months vs 31.5 months). In the REACH study of 552 rituximab-naive patients with relapsed CLL, the use of rituximab plus FC yielded a 32% improvement in progression-free survival. Progression-free survival was 5 months longer for the combination therapy compared with FC alone (26.7 months vs 21.7 months).
Adverse effects associated with the use of Rituxan for CLL may include, but are not limited to, the following:
The Rituxan drug label comes with the following Black Box Warning:
Infusion-Related Reactions: Rituxan administration can result in serious, including fatal, infusion-related reactions. Deaths within 24 hours of Rituxan infusion have occurred. Approximately 80% of fatal infusion reactions occurred in association with the first infusion. Monitor patients closely. Discontinue Rituxan infusion for severe reactions and provide medical treatment for Grade 3 or 4 infusion-related reactions. Severe Mucocutaneous Reactions Severe, including fatal, mucocutaneous reactions can occur in patients receiving Rituxan. Hepatitis B Virus (HBV) Reactivation: HBV reactivation can occur in patients treated with Rituxan, in some cases resulting in fulminant hepatitis, hepatic failure, and death. Screen all patients for HBV infection before treatment initiation, and monitor patients during and after treatment with Rituxan. Discontinue Rituxan and concomitant medications in the event of HBV reactivation. Progressive Multifocal Leukoencephalopathy (PML), including fatal PML, can occur in patients receiving Rituxan.
Rituxan (rituximab) is a monoclonal antibody that targets the CD20 antigen expressed on the surface of pre-B and mature B-lymphocytes. Upon binding to CD20, rituximab mediates B-cell lysis. Possible mechanisms of cell lysis include complement dependent cytotoxicity (CDC) and antibody dependent cell mediated cytotoxicity (ADCC). B cells are believed to play a role in the pathogenesis of rheumatoid arthritis (RA) and associated chronic synovitis. In this setting, B cells may be acting at multiple sites in the autoimmune/inflammatory process, including through production of rheumatoid factor (RF) and other autoantibodies, antigen presentation, T-cell activation, and/or proinflammatory cytokine production.
For additional information regarding Rituxan or chronic lymphocytic leukemia, please visit https://www.rituxan.com/