A 6-month randomized dose range study of OM-8980 in rheumatoid arthritis.

Sixty patients with active RA were evaluated over 6 months in a double-blind randomized dose range multicentre study comparing the efficacy and tolerance of three different doses of the slow-acting anti-rheumatic bacterial extract OM-8980 (6, 24 and 48 mg of active principle). No patients were withdrawn during the study. At the end of the 6-month trial, significant improvements were observed for the different RA signs and symptoms (Ritchie index, morning stiffness, swollen joints, grip strength, ESR, pain scale and categories) as well as for the concomitant intake of symptomatic drugs in the 24-mg dose group with respect to the 6-mg group and without significant differences between the 24- and 48-mg groups. Tolerance was very good with nine minor and transient side effects (five itching and four diarrhoea) reported altogether by seven patients, without establishment of a dose-effect correlation. In conclusion, the two higher doses of OM-8980, 24 and 48 mg, were significantly more efficient than 6 mg, with the effect of the 24-mg dose being even slightly superior to the 48-mg dose, confirming the former as the optimal and well-tolerated dose for the treatment of RA.