To evaluate the safety and clinical efficacy of administering an anti–interleukin-10 (anti–IL-10) monoclonal antibody (mAb) to systemic lupus erythematosus (SLE) patients with active and steroid-dependent disease. In addition, we sought to assess the effects of in vivo IL-10 neutralization on biologic markers of SLE.
Treatment consisted of 20 mg/day intravenous administration of an anti–IL-10 murine mAb (B-N10) for 21 consecutive days, with a followup period of 6 months. Six patients were studied.
Treatment was safe and well tolerated. All patients developed antibodies against B-N10. Cutaneous lesions and joint symptoms improved in all patients beginning during B-N10 administration and continuing to month 6. The SLE Disease Activity Index decreased from a mean ± SEM of 8.83 ± 0.91 on day 1 to 3.67 ± 0.67 on day 21 (P = 0.001), 1.50 ± 0.84 at month 2, and 1.33 ± 0.80 at month 6 (P < 0.001). At the end of followup, the disease was clinically inactive in 5 of the 6 patients. Prednisone administration was decreased from a mean ± SEM of 27.9 ± 5.7 mg/day on day 1 to 9.6 ± 2.0 mg/day at month 6 (P < 0.005). Activity of immune and endothelial cells rapidly decreased, as assessed by the early evolution of several biologic markers.
This is the first report of IL-10 antagonist administration to humans. The study shows the involvement of IL-10 in the pathogenesis of SLE, and indicates that the use of IL-10 antagonists may be beneficial in the management of refractory SLE.