Low-dose intravenous cyclophosphamide in systemic sclerosis: a preliminary safety study

Both oral and intravenous high-dose cyclophosphamide (CYC) regimens are associated with serious side effects when used for the treatment of systemic sclerosis (SSc). The aim of the present trial was to test the safety of low-dose intravenous CYC in patients with SSc. Eight SSc patients, in whom CYC treatment was warranted, were studied at baseline and after 6 months’ intravenous CYC treatment (500 mg pulses at weeks 0, 1, 2, 6, 10, 14, 18 and 22). Side effects probably related to CYC treatment were carefully investigated. The development of amenorrhea was assessed during the period of treatment and over the following 12 months. The therapy was well tolerated overall. No patient discontinued treatment because of side effects. Leukopenia, premature ovarian failure, hemorrhagic cystitis, microscopic hematuria and liver toxicity were never detected. The most common adverse events were mild and self-limiting nausea and weakness. Our data suggest that low-dose intravenous CYC is relatively safe, at least in the short term. Further studies are needed to assess both the efficacy and the long-term safety.