| Active, not recruiting | 4 | 43 | Europe | Hydroxychloroquine, Plaquenil, Placebo, Control | Guy's and St Thomas' NHS Foundation Trust, Medical Research Council | ANCA Associated Vasculitis, Microscopic Polyangiitis, Churg-Strauss Syndrome, Wegener Granulomatosis | 05/25 | 05/25 | | |