Previous randomized controlled trials for treatment of rheumatoid arthritis (RA) with acid-soluble chicken and bovine type II collagen (CII) have produced conflicting results. This randomized, double-blind, controlled trial examined the therapeutic effect of bovine CII tablets in RA.
CII tablets were prepared by adsorption onto a lactose base. Patients with a duration of RA of > or = 2 years and who had failed treatment with at least 1 slow-acting drug were recruited, provided that they had active arthritis. Patients were randomly assigned to receive either 0.05 mg, 0.5 mg, or 5 mg of CII or placebo daily for 6 months. All slow-acting drugs were stopped at least 4 weeks before starting CII, although prednisolone was permitted at dosages < 10 mg/day. Clinical assessments were performed at screening and at 0, 1, 4, 8, 12, 16, 20, and 24 weeks of treatment.
Fifty-five patients were recruited. Initially, there were no significant differences in mean Disease Activity Scores between groups. At 24 weeks, there was a significant difference (P = 0.041, by Kruskal-Wallis analysis of variance); the major components of this difference were attributable to relatively large decreases in the 0.5 mg CII group (19% of initial values) and to minimal decreases in patients receiving placebo (3% of initial values). Twenty patients had American College of Rheumatology 20% responses; 11 of these were in the 0.5 mg CII group and 3 were in each of the other groups, a significant difference (chi2 = 14.6, P = 0.002). There was no significant difference in any clinical measure between the placebo, 0.05 mg CII, and 5 mg CII groups. There were no side effects associated with CII treatment.
Treatment with 0.5 mg/day of bovine CII is well tolerated and produces small, but significant, disease improvement in RA. However, the therapeutic window is narrow. The difference between our results and those of other trials may relate to the dose, species, and formulation of the CII.