AIM OF STUDIES: To determine the optimal dose regimen for i.v. TNFR55-IgG1 in refractory rheumatoid arthritis.
218 patients with refractory rheumatoid arthritis were enrolled for two double-blind placebo-controlled multicenter trials (Europe and USA). They were treated with monthly i.v. placebo, 0.01, 0.05, 0.1 or 0.5 mg/kg TNFR55-IgG1 after a 4 week wash-out of DMARDs. An additional German trial compared biweekly i.v. 20 mg TNFR55-IgG1 and monthly 50 mg following a loading does of 100 mg in 60 patients.
TNFR55-IgG1 induced a substantial improvement already apparent one day after the first infusion. A maximal, dose dependent effect was reached after two weeks. Later, efficacy declined in parallel to an increase in anti-TNFR55-IgG1 antibodies resulting in an increased drug clearance. The drug was well tolerated with predominantly mild or moderate adverse events.
Intravenous TNFR55-IgG1 was well tolerated and effective in refractory rheumatoid arthritis but the treatment schedules tested could not stabilise the initial improvement.