Objective. To evaluate whether treatment with prasterone (dehydroepiandrosterone [DHEA]) would allow the dosage of prednisone (or an equivalent corticosteroid) to be reduced to <7.5 mg/day for 2 months or longer while maintaining stable or reduced disease activity in steroid-dependent women with systemic lupus erythematosus (SLE).Methods. In a double-blind, randomized trial, 191 female SLE patients receiving prednisone (10-30 mg/ day) were treated daily with either placebo, 100 mg of oral prasterone (an adrenal androgen), or 200 mg of oral prasterone for 7-9-months. At monthly intervals, corticosteroid dosages were reduced by algorithm in patients whose SLE Disease Activity Index (SLEDAI) score was stable or improved. Patients for whom a sustained reduction in the dosage of prednisone (<7.5 mg/day) was achieved for at least the last 2 months of the 7-9-month treatment period were classified as responders.Results. Response rates were 41% in the placebo group, 44% in the 100-mg prasterone group, and 55% in the 200-mg group (P ؍ 0.110, 200 mg versus placebo). Among the 137 subjects (45 in the placebo group, 47 in the 100-mg group, and 45 in the 200-mg group) who had active disease at baseline (defined as SLEDAI score >2), 29%, 38%, and 51%, respectively, were responders (P ؍ 0.031 for 200 mg prasterone versus placebo). Acne was the most common adverse event but was generally mild. Clinical and laboratory changes primarily reflected androgenic effects of prasterone.Conclusion. Among women with lupus disease activity, reducing the dosage of prednisone to <7.5 mg/day for a sustained period of time while maintaining stabilization or a reduction of disease activity was possible in a significantly greater proportion of patients treated with oral prasterone, 200 mg once daily, compared with patients treated with placebo.Systemic lupus erythematosus (SLE) is a chronic, autoimmune, inflammatory disease of unknown etiology. After puberty, SLE is more common in women than in men, with a ratio of 9:1 (1). Abnormalities of both estrogen and androgen metabolism have been described in SLE patients, including enhanced formation of 16-␣ hydroxyestrone, an active metabolite of estradiol (2,3), and depressed blood androgen concentrations (4). Androgen treatment induces a delay in the appearance of anti-DNA antibodies and the onset of nephritis and decreases mortality in female (NZB ϫ NZW)F 1 hybrid mice, a well-characterized animal model of SLE (5-7).