Rituximab Vasculitis Maintenance Study

Study Summary

Rituximab is now established as an effective drug for anti-neutrophil cytoplasmic antibody (ANCA) vasculitis following major European and US trials reported in 2010. After a time, its effect wears off and the disease can return. This occurs in at least half of patients within 2 years of receiving Rituximab. A preliminary study in Cambridge has suggested that repeating rituximab every six months stops the disease returning and is safe. The RITAZAREM trial will find out whether repeating rituximab stops vasculitis returning and whether it works better than the older treatments, azathioprine or methotrexate. It will also tell us how long patients remain well after the repeated rituximab treatments are stopped, and if repeated rituximab is safe. We should also learn useful information about the effects of rituximab on quality of life and economic measures. The trial results will help decide the best treatment for future patients who have their vasculitis initially treated with rituximab. RITAZAREM aims to recruit patients with established ANCA vasculitis whose disease has come back 'relapsing vasculitis'. All patients will be treated with rituximab and steroids and we anticipate that most will respond well. If their disease is under reasonable control after four months, further treatment with either rituximab (a single dose ever four months for two years) or azathioprine tablets will be chosen randomly. The patients in the rituximab and azathioprine groups will then be compared. Patients will be in the trial for four years. The study has been designed by members of the European Vasculitis Study group (EUVAS) and the Vasculitis Clinical Research Consortium (VCRC). It will include 190 participants from 30 hospitals in Europe, the USA, Australia and Mexico. RITAZAREM is being funded by Arthritis Research UK, the U.S. National Institutes of Health and by Roche/Genentech.

Primary Outcome

The primary efficacy outcome measure of the trial is relapse-free survival, where a relapse is either major or minor. The primary analysis will be a Cox regression model adjusted for the stratification factors (ANCA type, relapse severity and prednisone induction regimen) for the difference in the distribution of relapse-free survival between the rituximab arm and the azathioprine (control) arm (two-sided at α-level of 5%).

Interventions

• BIOLOGICAL Rituximab
• DRUG Azathioprine