Objective: To determine the safety and tolerability, as well as the clinical and immunologic effects, of 2-chloro-2'-deoxyadenosine (2-CdA) in patients with systemic lupus erythematosus-associated glomerulonephritis.
Methods: In a phase I study, 12 patients with proliferative lupus nephritis received 2-CdA either in weekly escalating intravenous treatments (0.15 mg/kg/week x 4, 0.1875 mg/kg/week x 4, 0.225 mg/kg/week x 4; n = 5) or in a continuous 7-day infusion (0.05 mg/kg/day; n = 7). Safety, renal improvement, and immunologic effects were evaluated for 12 months.
Results: Patients treated with 2-CdA showed peripheral lymphocyte depletion without a significant reduction in neutrophil, monocyte, or platelet numbers or hematocrit levels. Naive and memory T cells were decreased, as were lymphocytes with markers of early and late activation. Peripheral B cell depletion was not associated with significant decreases in serum immunoglobulin levels. Continuous infusion induced better clinical responses than weekly infusions, as evidenced by 1) the percentage of patients showing complete response (43% versus 0%), 2) the percentage with at least 50% reduction in proteinuria (43% versus 20%), 3) the percentage with at least a 50% reduction in urinary dysmorphic red cells (57% versus 0%), and 4) the percentage in whom cellular casts disappeared (43% versus 0%). Several infections occurred; these responded to standard antibiotic therapy.
Conclusion: In this pilot study, 2-CdA was safely administered to 12 patients with lupus nephritis. It induced prolonged reductions in lymphocyte populations and may be efficacious in selected patients with lupus nephritis when administered as a continuous infusion.