Effects of Tranilast on Pharmacokinetics of Methotrexate (MTX) in Patients With Rheumatoid Arthritis (RA)

THEORETICAL FRAMEWORK:The treatment outcomes in rheumatoid arthritis have dramatically improved with the recognition that the inflammatory component of disease needs to be suppressed optimally at every stage in its evolution. However, all existing conventional oral therapies are associated with limited efficacy and loss of effectiveness over time. Furthermore all of these therapies are associated with significant toxicity and tolerability problems. Another approach to treatment involves the use of biologic (protein based), parenterally administered therapies directed against important inflammatory molecules or cells involved in disease pathology. Despite the notable success of anti-TNF therapy, which is one of these biologics,approximately one third of patients do not respond adequately and the costs of drug production are very high. This causes rationing in all healthcare economies. There is therefore a need for new, safe, well tolerated and effective drugs that are cost effective. Tranilast (a tryptophan metabolite) is already licenced in Japan for the treatment for allergy. Basic science studies including those undertaken at The Kennedy Institute indicate that this drug suppresses the activity of a number of key inflammatory mediators as well as the activation of lymphocytes (white blood cells) responsible for the perpetuation of inflammation and associated tissue destruction in rheumatoid. Therefore, there was a rationale to test the effectiveness of tranilast in vivo for the treatment of arthritis. In an animal model of arthritis, tranilast effectively reduces joint swelling and read outs of pain. Since tranilast is well tolerated and safe in the licenced treatment indication in man, it is timely to test its effectiveness in rheumatoid arthritis. The majority of patients with this condition are treated with methotrexate often in combination with other anti-rheumatoid drugs. The current study is a prelude to a larger randomised controlled study investigating the efficacy of tranilast in rheumatoid arthritis. PURPOSE:This study will evaluate the pharmacokinetics, safety and tolerability of an oral medication, tranilast, in patients with rheumatoid arthritis who are on another disease modifying medication, methotrexate. DESIGN:The study is a randomised crossover pilot study with an optional higher dose open label phase. METHOD:During the study the patient will either receive tranilast (300mg twice a day) or a placebo drug for a period of seven days. The patient will then have a seven day break followed by another period of seven days in which the patient will receive the other medication. They will attend the clinic on at least 6 occasions(screening, day 2,3 8 and 9 then on 5 occasions in session 2 plus a follow up session. During the study blood samples will be taken to assess safety and serum concentrations of the study drug and interactions with methotrexate.