2 The technology
2.1 Rituximab (MabThera, Roche Products) is a chimeric (mouse/human) genetically engineered monoclonal antibody. It targets the CD20 surface antigen of mature B-cell lymphocytes. Rituximab has a marketing authorisation for the 'treatment of follicular lymphoma patients responding to induction therapy'. Other licensed indications for rituximab in non-Hodgkin's lymphoma include 'the treatment of previously untreated patients with stage III-IV follicular lymphoma in combination with chemotherapy'; 'the treatment of patients with stage III-IV follicular lymphoma who are chemoresistant or are in their second or subsequent relapse after chemotherapy'; and 'the treatment of patients with CD20 positive diffuse large B cell non-Hodgkin's lymphoma in combination with CHOP (cyclophosphamide, doxorubicin, vincristine, prednisolone) chemotherapy'.
2.2 Allergic and skin reactions are the most common adverse effects of rituximab infusion. Reactions during infusion can include bronchospasm and hypotension, which can be severe or life-threatening. Severe reactions occur more commonly in people with a high tumour burden, and the incidence and severity of infusion reactions decrease with successive infusions. Rituximab treatment can also be associated with blood and bone-marrow toxicity, characterised by neutropenia and leucopenia, which can lead to infections. In addition, treatment with rituximab may cause flu-like symptoms, and has been associated with progressive multifocal leukoencephalopathy. For full details of side effects and contraindications, see the summary of product characteristics.
2.3 For people with previously untreated follicular lymphoma that has responded to first-line induction treatment, the recommended dose of rituximab as maintenance treatment is 375 mg/m² body surface area, administered by intravenous infusion once every 2 months. Treatment should start 2 months after the last dose of first-line induction therapy and continue until the disease progresses, or for a maximum period of 2 years. The cost of one 100-mg vial is £174.63, and one 500-mg vial is £873.15 (excluding VAT; 'British national formulary' [BNF] edition 61). The manufacturer estimates that for a person with an average body surface area of 1.8 m², the average cost of rituximab maintenance treatment for 2 years is £14,669 (excluding VAT). Costs may vary in different settings because of negotiated procurement discounts.