Short term effects of intravenous pulses of cyclophosphamide in the treatment of connective tissue disease crisis.

A predominantly outpatient regimen of low dose intravenous cyclophosphamide was used to treat patients with serious progressive connective tissue diseases. Fifty five patients were treated with a total of 211 intravenous pulses of cyclophosphamide. Forty five patients had previously shown no response to a variety of other treatments. Low dose intravenous cyclophosphamide (500 mg) was given in 179 pulses and repeated pulses were given in most patients at weekly intervals for one to three weeks to induce disease remission. A good response was noted in 37 of 55 (67%) patients assessed four weeks after the pulses. Only 20 patients needed more than one such course of three pulses of intravenous cyclophosphamide during the observation period. The non-responders were characterised by longstanding disease and irreversible histological findings in renal and muscle biopsy samples. Patients with vasculitis, notably Wegener's granulomatosis, showed the most immediate response, and in most patients the amount of corticosteroids required was markedly reduced. In some patients steroids were completely stopped during the follow up period. The most striking observation of this effective but more conservative regimen was the low incidence of major side effects such as neutropenia and infections. It is concluded that low dose pulses of intravenous cyclophosphamide are well tolerated and are an effective treatment for patients with aggressive connective tissue diseases.