A Sequential Trial Comparing Cyclophosphamide and Azathioprine as Adjuncts in the Treatment of Systemic Lupus Erythematosus*

Summary: Azathioprine and cyclophosphamide in doses of 200 mg/day for a proposed duration of one year were compared as adjuncts to prednisolone in the treatment of systemic lupus erythematosus (SLE) in relapse, in a model trial designed to extract maximum information by using multiple indices in few patients. Neither drug proved clearly superior. The possibly greater effectiveness of cyclophosphamide was attributed to a relatively higher effective dosage; however this was offset by more frequent side effects, and in particular the planned 12 months' course of therapy was completed by only one of five cyclophosphamide-treated patients as compared with four of five azathioprine-treated patients. Continuing the trial by including more patients or prolonging treatment was not likely to have yielded additional information. This study on SLE in relapse indicated, at most, that azathioprine and cyclophosphamide may have an accessory role in therapy of this disease, for prednisolone-sparing effects.