Background and importance Rituximab is a chimeric, anti-CD20 monoclonal antibody. In addition to its approved indications, its off-label use has increased in the management of a variety of neurological diseases.

Aim and objectives To describe rituximab prescriptions in the neurology department, and to evaluate the scientific evidence for off-label indications to rationalise its use.

Material and methods A retrospective observational study can conducted in all neurology patients receiving rituximab treatment from January 2012 to January 2020. The following data were collected: demographics (sex and age), clinical (indication), therapy related (dose, posology, previous treatments and adverse events) and economic (annual cost). The Oxford 2011 levels of evidence (LE) was used to categorise evidence.

Results 66 patients (63% women, average age 45.6±12.2 years) were included, 100% receiving off-label use. Indication and LE, describing benefit/no benefit/harm: relapsing–remitting multiple sclerosis (RRMS), LE: 2, no benefit (34 patients, 52,3%); primary/secondary progressive multiple sclerosis (PMS), LE: 2, no benefit (6 patients, 9,2%); optic neuromyelitis (ONM), LE: 4, benefit (7 patients, 10,8%); myasthenia gravis (MG), LE: 4, benefit (6 patients, 9,2%); demyelinating inflammatory chronic polyradiculoneuropathy (DICP), LE: 4, benefit (1 patient, 1,5%). Optic neuritis (4 patients); isolated CNS vasculitis (2 patients), other neurological disorders or syndromes (5 patients). Literature review found no good quality evidence for these last diseases.

Rituximab was firstline immunomodulatory treatment for all ONM, MG and DICP patients. 21 patients (52.5%) with RRMS and PMS received it rituximab as, at least, thirdline therapy. Most habitual dosage regimen was: 500–1000 mg for the first month (days 1 and 15, repeated 6 months later) with a maintenance dose of 500–1000 mg every 6–12 months.

Four patients had infusion related reactions. 12 infections: respiratory (6), urinary (5) and dermic (1), and 1 case of breast cancer were reported.

Average cost per patient was 6366€ during the first year and 2546€ each following year. 78% of this cost was spent in treating pathologies for which rituximab has shown poor evidence.

Conclusion and relevance Off-label rituximab is extensively used in neurological pathologies with no strong evidence. As many adverse events have been observed, close monitoring of patients is suggested. The high economic impact makes it necessary to rationalise rituximab prescriptions and optimise the efficiency of sanitary resources.

Conflict of interest No conflict of interest