Background The therapeutic indications for rituximab are: Hodgkin's lymphoma, chronic lymphocytic leukaemia and rheumatoid arthritis.

Purpose The aim of this study was to review the off-label use of rituximab in our hospital.

Materials and methods Retrospective study of rituximab in off-label indications from October 2009 to June 2011. Data collected: age, sex, diagnosis, posology, number of doses planned and administered and cost of treatment.

Results Rituximab was used for 21 patients (76.1% women) with a mean age of 39.3 years (11-71). The indications were antisynthetase syndrome (dermatomyositis), autoimmune encephalitis, nephrotic syndrome, neoplastic cerebellar syndrome, pemphigus foliaceus, acquired haemophilia A, acute renal rejection (2), autoimmune thrombocytopenic purpura (ITP) (2), systemic lupus erythematosus (SLE) (5) and neuromyelitis optica (6). Posology varied according to the indication. SLE and antisynthetase syndrome: 1 g every 14 days, 2 doses. Nephrotic syndrome, ITP, pemphigus foliaceus, haemophilia A and neuromyelitis optica: 375 mg / m2 intravenous once weekly, 4 doses and in the last indication there is an option of retreatment with 2 doses of 1000 mg depending the CD19 count. Neoplastic cerebellar syndrome: 375 mg/m2 intravenous every 28 days, 4 doses. Acute humoral rejection: 500 mg (single dose) for 1 patient once weekly, 4 doses for the other patient. 14.2% of patients didn't start treatment with rituximab and 72.2% received the planned total doses. Only 1 patient received 2 doses as a retreatment for neuromyelitis optica. The off-label use of rituximab meant a cost of 90,638 €.

Conclusions Rituximab is widely used in autoimmune pathologies as a therapeutic alternative in patients who have failed conventional treatment, although its use is not supported by large clinical trials. The high cost and its wide use warrant large randomised controlled clinical trials to demonstrate its efficacy.