Patients with adult-onset rheumatoid arthritis will be enrolled. They will be dosed with
repeated intravenous doses of BTT-1023 or placebo. During the trial, the safety of the
treatments and the pharmacokinetics of BTT-1023 will be assessed. The patient allocation to
treatment groups will occur at random, and the actual treatment will not be revealed to the
investigator or to the patient during the trial.