A Clinical Trial of a New Anti-Inflammatory/Analgesic Compound in Rheumatoid Arthritis – GP 45 840

Abstract

GP 45 840, N-( 2-6-dichlorophenyl)-o-aminophenylacetic acid, sodium salt, has been shown pharmacologically to have good analgesic and anti-inflammatory properties. GP 45 840 in progressively increasing dosage from 50 to 150 mg per day was compared with a placebo in a double-blind cross-over trial in thirteen patients with rheumatoid arthritis, GP 45 840 and placebo each being given for one week. GP 45 840 produced no more intolerance than did placebo therapy. The rather high mean white cell count of the placebo period was lower during treatment with GP 45 840 but n ever below the normal range. GP 45 840 had no effect on weight, erythrocyte sedimentation rate, renal and liver function tests or other haematological tests. The following features were assessed twice weekly; pain, morning stiffness, grip strength, swelling, tenderness, and range of certain joints, requirements of supplementary analgesics and drug intolerance. An improvement, independent of the effects of GP 45 840 was observed in several of the features assessed, including decrease in potentially reversible joint swelling, but GP 45 840 resulted in a further significant reduction in pain and requirements of supplementary analgesics. An anti-inflammatory effect on early synovitis of the p.i.p joints was demonstrated though not conclusively proved. The trial procedures were sufficiently sensitive to demonstrate significant improvement in many symptoms and signs of rheumotoid arthritis due to overall in-patient treatment during a two week period. A new method of analysis of p.i.p size was used. Joints were graded clinically into four categories of joint swelling. Although overall measurements showed no significant change, a significant decrease in joint size was demonstrable in joints graded as having ‘definite’ synovial inflammatory changes.