One hundred five patients were enrolled in a 12-week, randomized, prospective, double-blind, placebo-controlled trial of recombinant human gamma-interferon (rHu gamma-IFN) for the treatment of rheumatoid arthritis. Fifty-four patients received rHu gamma-IFN and 51 received placebo. Forty-two patients in each group completed the 12-week trial. Some clinical improvement occurred in both groups of patients. Although the improvement with rHu gamma-IFN was greater than that with placebo, the differences were generally not statistically significant.

OBJECTIVE:To define clinical and laboratory outcomes of longterm recombinant interferon-gamma (rIFN-gamma) treatment of patients with rheumatoid arthritis (RA).METHODS:Patients with RA (70) completing a 12-week multicenter double blind trial comparing rIFN-gamma with placebo were enrolled in a longterm prospective protocol evaluating rIFN-gamma in RA.RESULTS:The majority of patients sustained clinical improvement for one year. Eight (11%) patients with RA continued to receive rIFN-gamma after 5 years. One patient fulfilled remission criteria. rIFN-gamma was well tolerated with remarkably few suspected adverse drug reactions. Forty-seven (67%) patients discontinued rIFN-gamma because of lack of efficacy, 7 (10%) because of concurrent illnesses, 5 (7%) were not compliant to study protocol, 3 (4%) developed suspected adverse drug reactions for a total of 62 (89%) withdrawals over the 5 years of followup. Patients continuing rIFN-gamma treatment for 5 years had lower initial total leukocyte and neutrophil counts and higher hemoglobin and hematocrit levels than patients who discontinued rIFN-gamma during the 5-year followup.CONCLUSIONS:Longterm treatment of RA with rIFN-gamma was generally well tolerated. Although many patients maintained sustained clinical improvement for at least one year, the main reason for discontinuing the drug over 5 years was the lack of continued benefit.

Seventy patients with rheumatoid arthritis (RA) completing a 12-week multicenter double blind trial comparing recombinant human interferon-gamma (r-IFN-gamma) with placebo were enrolled in a longterm prospective protocol evaluating r-IFN-gamma in RA. Forty (57%) patients after 1 year and 26 (37%) patients after 2 years continued the drug with sustained clinical benefit. Over 2 years, r-IFN-gamma was discontinued in 44 patients (lack of efficacy--25, withdrawn consent--7, noncompliant--4, suspected adverse drug reactions--2, concurrent illness--6). Two years of treatment with r-IFN-gamma were well tolerated with sustained clinical benefit in some patients with few significant adverse drug reactions.