Recombinant human interleukin 10 in the treatment of patients with mild tomoderately active Crohn's disease

Background & Aims: Interleukin 10 (IL-10) is an anti-inflammatory, immunomo dulatory cytokine that regulates mucosal inflammation. This study evaluated the safety, tolerance, and efficacy of recombinant human IL-10 (rhuIL-10) for mild to moderately active Crohn's disease. Methods: We conducted a 24-w eek multicenter, prospective, randomized, double-blind, placebo-controlled, and sequential-escalating-dose study. Ninety-five patients with Crohn's Di sease Activity Index of 200-350, not presently undergoing corticosteroid, m esalamine, or immunosuppressive therapy, were treated with subcutaneous rhu IL-10 (1, 5, 10, or 20 mug/kg) or placebo once daily for 28 consecutive day s. Patients were followed up for 20 weeks after treatment. Evaluation of sa fety and tolerance was the first objective, and efficacy was the second obj ective. Results: Adverse effects were dose-related, mild-to-moderate in sev erity, and reversible. Asymptomatic and reversible anemia and thrombocytope nia were observed at higher doses. No withdrawal or delayed adverse effects were evident during 20 weeks of follow-up. At the end of treatment (day 29 ), intent-to-treat analysis showed that 23.5% (confidence interval [CI], 6. 8%-49.9%) of patients receiving 5 mug/kg rhuIL-10 experienced clinical remi ssion and endoscopic improvement; 0% (CI, 0%-14.8%) of patients in the plac ebo group did. Higher doses of recombinant human IL-10 were less effective than 5 mug/kg. No rhuIL-10 serum accumulation and no antibody against IL-10 were detected after 4 weeks. Conclusions: Subcutaneous rhuIL-10 administer ed daily for 28 days to patients with mild to moderately active Crohn's dis ease is safe, well-tolerated, and shows clinical and endoscopic improvement .