On-Demand, Low-Dose Rituximab Proves Effective in Treating RA

Recent studies, including the ALTERRA study, have reported that low and very low doses of rituximab are effective in treating rheumatoid arthritis (RA), and a new study that describes the real-world use of rituximab in a single center in Spain suggests that a low dose of rituximab, administered on-demand rather than at predetermined intervals, provides a good long-term treatment option for some patients.

The retrospective cohort study considered adult patients with RA who were treated with rituximab from 2005 to 2014, with a follow-up period through 2015. In total, 114 patients with 409 cycles of treatment were considered.

Rituximab, primarily used as a second-line biologic therapy, was used in a cost-saving and adverse-event reducing on-demand schedule in 94.6% of patients; these patients were assessed for signs of relapse and the need for another rituximab infusion at their regularly scheduled visits, and they also had the option of contacting a healthcare provider by phone if they felt that they were relapsing. The remaining 5.4% of patients were on a fixed 6-month dosing schedule.

The researchers report that the median number of rituximab cycles per patient was 3 (range, 1-11), and a dose of 1000 mg, versus the standard 2000 mg, was used in 31.8% of treatment cycles. Overall, 91.5% of first cycles used the recommended 2000 mg dose, but the percentage of doses that used the 1000 mg dose rose to 80% to 100% of patients with more than 6 cycles of treatment.

Overall, there was an average disease activity improvement after rituximab administration after each cycle. Duration of response could only be measured in the on-demand cycles (n = 314). The median response duration for patients with on-demand treatment was 10 months (interquartile range, 7-13).

A multivariable analysis revealed that older age (65 years or older) and higher number of rituximab cycles were significantly associated with longer response duration. When rituximab was used as a third biologic or higher, the response duration was approximately 2 months shorter than in those patients who used the drug as a first- or second-line therapy. The dose per cycle was not associated with response duration.

“Our data suggest that, after a successful first cycle of 2000 mg, retreatments with rituximab can be scheduled as cycles of 1000-mg single [infusions]…resulting in a comfortable schedule of treatment with acceptable control of disease activity in most patients,” conclude the authors.

Reference

Cañamares-Orbis I, Merino L, López J, et al. Experience with the use of rituximab for the treatment of rheumatoid arthritis in a tertiary hospital in Spain: RITAR study. [Published online July 19, 2018.] J Clin Rheumatol. doi: 10.1097/RHU.0000000000000845.