[Treatment of rheumatoid arthritis (RA) with anti-TNF-alpha antibody (Remicade). Individual monitoring of bioavailability and immunogenicity--secondary publication].

Remicade/infliximab is effective in rheumatoid arthritis (RA), but response failure is frequent. Sera from 106 RA patients were monitored using an RIA for functional infliximab and an RIA for anti-infliximab antibody (Ab). S-infliximab varied considerably, e.g. 0-22 microg/ml before the 3rd infusion, and 44% were Ab-positive after 6 months. Low s-infliximab was associated with Ab development and later therapeutic failure, and high Ab levels could be related to dose increases, side-effects and cessation of therapy. Pharmacological monitoring should help optimize anti-TNF therapies.