Study objective: To determine the effect of monthly intravenous cyclophosphamide therapy in patients with systemic lupus erythematosus and autoimmune thrombocytopenia.
Design: Uncontrolled, retrospective clinical study.
Setting: Government referral-based research hospital.
Patients: Seven patients with systemic lupus erythematosus and 2 or more months of thrombocytopenia refractory to or requiring excessive doses of corticosteroids. Two patients had also failed to respond to splenectomy and repeated intravenous methylprednisolone infusions. Six patients had severe active renal disease at the time of treatment.
Interventions: Cyclophosphamide, 0.75 to 1.0 g/m2 body surface area, was given intravenously every month for at least 4 months. Prednisone dose ranged between 0.5 to 1.0 mg/kg.d.
Measurements and main results: All seven patients had normal platelet counts within 2 to 18 weeks after cyclophosphamide treatment (one to four doses). Prednisone was tapered to 0.25 mg/kg on alternate days in all patients. All six patients had significant improvement in their renal disease and lupus serologies. Cyclophosphamide was discontinued after four to six doses in five patients. Four patients maintained normal platelet counts on low dose, alternate-day prednisone for a mean of 5.6 years of follow-up. Two patients had recurrence of thrombocytopenia 1 to 3 years after discontinuing cyclophosphamide.
Conclusions: Monthly intravenous cyclophosphamide is potentially useful for the management of autoimmune thrombocytopenia in patients with systemic lupus erythematosus who are refractory to or dependent on unacceptably high doses of corticosteroids, or are experiencing side effects of conventional medical or surgical treatment.