Rituximab in rheumatoid arthritis and the risk of malignancies: report from a French cohort.

Objective: To determine in real-life conditions the safety of treatment with rituximab (RTX) in patients with rheumatoid arthritis (RA) regarding malignancies.

Methods: Analysis of safety data from a cohort of RA patients who received at least one course of RTX. RA patients with previous malignancies were followed-up and compared to the group of patients with no history of malignancy.

Results: One hundred and eighty-six RA patients, 33 (17.7%) males, the mean age and disease duration were 55.8 ± 13.0 and 14.5 ± 11.1 years, respectively. The mean follow-up was 22.3 ± 15.1 months, corresponding to a follow-up of 346 pt-years of RTX exposure. Among these, 24 (12.9%) patients had a history of a prior malignancy. Five cancers were diagnosed during follow-up with four new malignancies (1 prostate, 1 breast, 1 colon and 1 cervical cancers) and one recurrence of a known breast cancer. The overall cancer rate was 1.45/100 pt-years (95%CI: 0.19 to 2.70), which is comparable to previously studied DMARD-treated cohorts. No new hematopoietic neoplasms were reported and the six lymphomas that have been in remission prior to RTX-therapy remained under follow-up. The baseline demographic and disease characteristics and the cancer-risk of the 24 patients who presented with a prior malignancy were similar to those with no cancer history (162 patients).

Conclusions: Although based on a modest number of observed cancers, and despite selection bias (12.9% of prior malignancies in our RTX treated RA), this observational study suggests that RTX does not increase the cancer risk in RA patients.