A Cochrane review included 32 studies (of which one study is still ongoing) with a total of 1 443 subjects. Alkylating agents (cyclophosphamide and chlorambucil) significantly reduced the risk of relapse at 6 to 12 months (RR 0.43, 95% CI 0.31 to 0.60) and 12 to 24 months (RR 0.20, 95% CI 0.09 to 0.46) compared with prednisone alone. In the single chlorambucil versus cyclophosphamide trial, there was no observed difference in relapse risk at two years (RR 1.31, 95% CI 0.80 to 2.13; 1 study, n=50). There was no significant difference at one year between intravenous and oral cyclophosphamide (RR 0.99, 95% CI 0.76 to 1.29). Cyclosporin was as effective as cyclophosphamide and chlorambucil (one trial each) and levamisole was more effective than steroids alone (RR 0.47, 95% CI 0.24 to 0.89; 7 studies, n=375). However the effects of cyclosporin and levamisole were not sustained once treatment was stopped. In one small study cyclosporin significantly reduced the relapse rate compared with mycophenolate mofetil (MD 0.75, 95% CI 0.01 to 1.49). Limited data from a cross-over study suggested that cyclosporin was more effective than mycophenolate mofetil in maintaining remission. In steroid- and cyclosporin-dependent disease, rituximab significantly reduced the risk of relapse at 3 months compared with conventional therapy. Mizoribine (one study) and azathioprine (two studies) were no more effective than placebo or prednisolone alone in maintaining remission.