A double-blind, placebo-controlled study of anti-CD5 immunoconjugate in patients with rheumatoid arthritis

Objective. To evaluate the efficacy of an anti-CD5 ricin-linked immunoconjugate (CD5-IC) in patients with rheumatoid arthritis (RA). Methods. A total of 104 evaluable patients were enrolled in a multicenter, double-blind, multiple-dose, placebo-controlled study of CDS-IC. Results. Treatment with CDS-IC in doses up to 8 mg/m(2)/day for 4 days in 1 month failed to produce marked or prolonged T cell depletion and was no more effective than placebo in ameliorating disease manifestations. An unexpectedly high placebo response was observed in 48% of the patients, Adverse events were correlated with the dose of CD5-IC, but the treatment was generally well-tolerated. Conclusion. At the doses used in this study, CDS-IC was ineffective for treating RA.