Rituximab for the treatment of relapsed or refractory chronic lymphocytic leukaemia

Rituximab (MabThera, Roche) is a chimeric monoclonal antibody that binds selectively to the CD20 antigen expressed on the surface of mature B lymphocytes and tumour cells that express CD20. Rituximab is licensed for the treatment of patients with previously untreated and relapsed/refractory chronic lymphocytic leukaemia. The summary of product characteristics (SPC) states that only limited data are available on efficacy and safety for patients previously treated with monoclonal antibodies including rituximab or patients refractory to previous rituximab plus chemotherapy. Rituximab is administered intravenously, once every 4 weeks for a total of 6 cycles; a complete course of treatment with rituximab lasts 24 weeks. Dosing is calculated according to body surface area, with an initial dose of 375 mg/m² followed by 500 mg/m² for all subsequent doses. Six cycles of rituximab equate to a total dose of 2,875 mg/m². The SPC states that rituximab should be administered under the close supervision of an experienced physician, and in an environment where full resuscitation facilities are immediately available.

The most frequently observed adverse events in people receiving rituximab are infusion-related reactions, including cytokine release syndrome. The majority of these reactions occur during the first infusion. Serious but rare adverse events associated with rituximab include neutropenia and leucopenia (including febrile neutropenia), infections (predominantly bacterial and viral) and cardiovascular events (hypotension, hypertension, arrhythmias and angina). Very rare serious adverse events include hepatitis B reactivation and progressive multifocal leucoencephalopathy. For full details of side effects and contraindications, see the SPC.

Rituximab is available in 100 mg (10 ml) and 500 mg (50 ml) vials. The cost of a 100 mg vial is £174.63 and a 500 mg vial is £873.15 (excluding VAT; BNF edition 58). For a person with a body surface area of 1.86 m², the cost of rituximab for the first dose is £1,222 and for subsequent doses is £1,746, including wastage of excess rituximab. The total cost of rituximab is £9,954 per course. Costs may vary in different settings because of negotiated procurement discounts.