Results from a recently pilot study published in the journal Arthritis & Rheumatology showed that in patients with rheumatoid arthritis (RA), atacicept combined with rituximab had no new safety issues but also was not associated with clinical benefits.
Evidence has shown that the use of the B cell-depleting agent rituximab results in clinical improvements in disease activity in patients with rheumatoid arthritis (RA). However, not all patients benefit from its use. Atacicept, a recombinant fusion protein designed to inhibit B cells, can also suppress autoimmune disease. To explore the tolerability and safety of both these agents combined in patients with active RA receiving re-treatment with rituximab, in the study entitled “Safety and Efficacy of Atacicept in Combination With Rituximab for Reducing the Signs and Symptoms of Rheumatoid Arthritis”, R.F. van Vollenhoven, MD, PhD, from the Karolinska Institute in Stockholm, Sweden, and colleagues conducted a Phase II, randomized, double-blind, placebo-controlled pilot clinical trial.
The study included a 7-week treatment period with rituximab, a 25-week treatment period with atacicept/placebo, and a 32-week follow-up period post-treatment. In the rituximab period, all RA patients received two 1000-mg doses of rituximab by intravenous infusion, 2 weeks apart (week 1 and week 3). At week 7 (after 28 days without treatment), patients were randomly assigned (2:1) to receive subcutaneous treatment with atacicept at a dose of 150 mg or with a placebo, once per week for 25 weeks.
Results showed that atacicept was not associated with a decrease in C-reactive protein, while greater reductions in erythrocyte sedimentation rates were seen after week 12. Greater reductions in immunoglobulin (Ig) G, IgM and IgA at week 32 were observed in patients who received atacicept. No differences in the American College of Rheumatology response rates or DAS28 were observed between treatment groups.
According to the researchers, these findings indicate that “Atacicept exerted clear biologic effects, but no additional clinical benefit was observed. Any evidence of an effect of atacicept on delayed B cell re-expansion following rituximab mediated depletion could not be evaluated, since there was virtually no recovery of B cells in the placebo group during the followup period. These findings, therefore, do not suggest that the combination of atacicept and rituximab should be pursued as a therapeutic option for patients with RA.”