A clinical and biochemical evaluation of etretinate in rheumatoid arthritis.

Etretinate (Tigason; Roche), which is effective in the treatment of psoriatic arthritis has immunomodulating activity in vivo. We have therefore assessed this drug in an open clinical and biochemical assessment of 24 weeks duration in rheumatoid arthritis. The treatment dose was 1.0 mg/kg/day for the first 4 weeks reducing to 0.5 mg/kg/day thereafter. There was a modest clinical improvement though this only reached statistical significance for joint circumference at 12 and 16 weeks (P less than 0.05). Biochemical improvement only reached levels of statistical significance for IgM at week 16 (P less than 0.01). Eight out of 15 patients had discontinued the drug because of side-effects by week 12 and only three out of 15 patients showed individual improvement by week 24. Some biochemical parameters (ESR) worsened. These results suggest only modest clinical efficacy and use of the drug in rheumatoid arthritis is likely to be curtailed by unacceptable side-effects. The improvement in biochemical variables that occurs when the drug is used in psoriatic arthritis does not occur in rheumatoid arthritis.