Non-Hodgkin’s lymphoma, Refractory or relapsed follicular lymphoma: As a single agent, 375 mg/m2 infusion once wkly, for 4 doses at an initial rate of 50 mg/hr. May increase by 50 mg/hr every 30 min. If tolerated, subsequent infusions can be started at 100 mg/hr and increased by 100 mg/hr every 30 min. Max rate: 400 mg/hr. When used with CVP (cyclophosphamide, vincristine and prednisolone) for follicular lymphoma or CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone) for diffuse large B-cell lymphoma, 375 mg/m2 given on day 1 of the chemotherapy cycle after corticosteroid regimen, for up to 8 cycles. For patients who were treated with 6-8 cycles of CVP chemotherapy and have not progressed, 375 mg/m2 may be given once wkly for 4 doses, may repeat every 6 mth, for up to 16 doses. Maintenance: 375 mg/m2 given once every 3 mth (those who have responded to induction chemotherapy), once every 2 mth initiated 2 mth after the last dose of induction chemotherapy (previously untreated) for a max period of 2 yr.
Chronic lymphocytic leukaemia: 375 mg/m2, given on the day prior to chemotherapy in cycle 1, followed by 500 mg/m2 on day 1 (every 28 days) of cycles 2-6.
Rheumatoid arthritis: Given as two 1 g IV infusion doses, separated by 2 wk and in combination with methotrexate. Corticosteroids may be given before each infusion to minimise the risk and severity of infusion reactions.
Rituximab is a chimeric monoclonal antibody to CD20 antigen which regulates cell cycle initiation. It binds to the antigen on the cell surface, activating complement-dependent B-cell cytotoxicity; and to human Fc receptors, mediating cell killing through an antibody-dependent cellular toxicity.
Duration: Detectable in serum 3-6 mth after completion of therapy; B-cell recovery 6-12 mth following completion of therapy.