BARCELONA, Spain—Clinicians and rheumatoid arthritis (RA) patients can be more assured of the safety of single or multiple courses of rituximab (Rituxan®, Genentech Inc/Biogen Idec) in the wake of data presented by Ronald F. van Vollenhoven, MD, at the 2007 EULAR meeting in Barcelona. According to Dr. van Vollenhoven, with the rheumatology department at Karolinska University Hospital, in Stockholm, Sweden, an analysis of two or more cycles of rituximab in clinical trials showed no increase in the rate of adverse effects (AEs), and no opportunistic infections, reactivations of viral infections, or tuberculosis.¹

"This confirms the safety profile of rituximab for repeated use in RA," Dr. van Vollenhoven said.

The analysis from phase IIa, IIb, and III studies included 1053 RA patients who received up to seven courses of rituximab. Dr. van Vollenhoven focused on patients who had completed two cycles (n = 684), three cycles (n = 400), or five cycles (n = 111) of rituximab. The duration of a cycle is typically 7 to 8 months, so the analysis included more than 2 years of follow-up for 700 patients and more than 3 years of follow-up for 120 patients.

"Overall, the incidence of adverse events decreased from 88% after a first cycle of rituximab to 81%, 72%, and 65% following cycles two, three, and four, respectively," Dr. van Vollenhoven said. Serious AEs followed a similar pattern.

He also noted that acute infusion reactions upon first course of rituximab became less of a problem with each succeeding course.

Although the proportion of patients with below-normal IgM or IgG levels increased with additional treatment courses, infections did not increase. Malignancies were likewise not much of a problem—there were no lymphoproliferative malignancies and no increased risk of malignancy with additional courses of treatment, Dr. van Vollenhoven said.

In related data from the EULAR meeting, Edward Keystone, MD, et al reported sustained efficacy for up to three repeated courses of rituximab in TNF-inhibitor-resistant RA,² and Roger M. Thurlings, MD, PhD, et al examined the dynamics of synovial B-cell response to rituximab.³

According to Dr. Thurlings, "Rituximab treatment leads to a rapid and significant decrease in synovial B-cell numbers after 1 month, with a further reduction after 4 months. Four months after treatment, a reduction in lymphocyte aggregate numbers and size was found, associated with clinical improvement."

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References

1. van Vollenhoven R, Emery P, Bingham C, et al. Long-term safety data from extended follow-up and repeat use of rituximab in rheumatoid arthritis. Presented at: EULAR 2007 Meeting; June 13-16, 2007; Barcelona, Spain. Abstract OP0119.
2. Keystone E, Fleischmann RM, Emery P, et al. Repeated treatment courses of rituximab in rheumatoid arthritis: sustained efficacy in patients with an inadequate response to one or more TNF inhibitors. Presented at: EULAR 2007 Meeting; June 13-16, 2007; Barcelona, Spain. Abstract SAT0012.
3. Thurlings RM, Vos K, Wijbrandts CA, et al. Dynamics of the synovial B cell response to rituximab therapy in rheumatoid arthritis: evaluation of serial synovial biopsies during the first four months of treatment. Presented at: EULAR 2007 Meeting; June 13-16, 2007; Barcelona, Spain. Abstract OP0229.