Background and importance A large number of patients with systemic autoimmune diseases (SAD) do not respond or relapse to firstline therapies. Current guidelines recommend the off-label use of rituximab for many severe refractory SAD even though most of the available data rely on observational studies and case reports

Aim and objectives The aim of this study was to analyse the efficacy and safety of the off-label use of rituximab for patients with severe refractory SAD in a tertiary hospital

Material and methods Off-label use of rituximab between January 2016 and December 2018 was reviewed. Clinical data were collected retrospectively. Therapeutic response was evaluated after 12 months of rituximab initiation based on clinical judgement: complete response was defined as no disease activity, partial response as a significant improvement (>50% of initial disease activity) and no response if there was no improvement or worsening of symptoms

Results A total of 52 applications were analysed. There were 28 men (54%) and 24 women (46%) with a mean age of 54.41 years (SD 15.31). The indications for rituximab included systemic lupus erythematosus (SLE) (17.3%), glomerulonephritis (15.4%), inflammatory myopathy (9.6%), cryoglobulinaemia (7.7%), polyneuropathy (7.7%) and other SAD. As for previous therapies, 42 patients (82.4%) received corticosteroids and 37 (71.2%) received at least one immunosuppressive drug.

From all patients with an assessable treatment (n=47), 70.2% achieved an improvement in disease after 12 months: 34% (n=16) a complete response and 36% (n=17) a partial response. The most favourable results were found in the treatment of SLE, glomerulonephritis, cryoglobulinaemia, multiple sclerosis and optic neuromyelitis in which >80% of patients obtained a complete or partial response.

Adverse events were reported in 22 patients (42.3%): the most frequent were infections (n=7) followed by infusion related reactions (n=3). No serious or death related adverse events were reported

Conclusion and relevance Rituximab had acceptable tolerance and reduced disease activity in some severe refractory SAD. Future controlled trials are needed to confirm the potential use of rituximab in patients with SAD. In the meantime, it is necessary to closely follow-up these patients.

References and/or acknowledgements 1. Ramos-Casals M, et al. Off-label use of rituximab in 196 patients with severe, refractory systemic autoimmune diseases. Clin Exp Rheumatol 2010;28:468–476.

No conflict of interest.