An international, open label, randomised controlled trial comparing rituximab with azathioprine as maintenance therapy in relapsing ANCA-associated vasculitis (RITAZAREM)

© 2015 Elsevier Masson to achieve long-term B cells depletion. Patients were closely monitored during 46.5 (2–88) months follow-up with clinical and serological surveillance. They received a RTX cumulative dose of 8 g (2–13). Results.– Median serum Ig levels declined continuously – but not gradually – after each RTX re-treatment. The biggest decline in Ig took place after the first RTX round. IgM and IgG levels were below normal in respectively 22 (65%) and 16 (47%) patients – 15 patients (44%) with combined low levels of IgM and IgG – already after the first round. Eleven patients (29%) had a cumulative CYC dose of 50 g or more and they had lower levels of total Ig after the first 3 RTX rounds and lower levels during RTX maintenance. However the 12 patients (32%) receiving CYC in combination with RTX at induction had bigger overall decline in IgG (3.6 vs 2.2 g/L P = 0.028), IgA (0.78 vs 0.32 g/L P = 0.028), IgM (0.53 vs 0.26 g/L) and total Ig (4.9 vs 2.9 g/L P = 0.030) at last visit compared to those receiving RTX without CYC. Conclusion.– Ig decrease the most after the first RTX round under RTX maintenance. While a high cumulative CYC dose (> 50 g) decreases Ig levels at all time during RTX maintenance, the combination of CYC-RTX at initiation has a synergistic effect with bigger decline of Ig at last visit.