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Arthritis Rheum. 1996 Jul;39(7):1092-101.

Dose-range and dose-frequency study of recombinant human interleukin-1 receptor antagonist in patients with rheumatoid arthritis. The IL-1Ra Arthritis Study Group.

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Synergen Inc., Boulder, Colorado, USA.



To preliminarily evaluate the safety and efficacy of different dose levels and dosing frequencies of recombinant human interleukin-1 receptor antagonist (rHuIL-1Ra) in the treatment of patients with rheumatoid arthritis (RA).


One hundred seventy-five patients with active RA were enrolled in a randomized, double-blind trial of rHuIL-1Ra administered by subcutaneous injection. There were 9 treatment groups in the trial. During the initial 3-week treatment phase, patients were treated with 20, 70, or 200 mg rHuIL-1Ra, administered either once, 3 times, or 7 times per week, followed by a 4-week maintenance phase, during which all patients received the treatment-phase dose once per week. To maintain the blindness of the study, patients received daily injections of either rHulL-1Ra or placebo on the days rHuIL-1Ra was not administered.


Recombinant HuIL-1Ra was well tolerated. The most frequent adverse event was injection-site reactions, which were reported in 62% of patients and caused 8 patients (5%) to withdraw prematurely from the study. Five patients (3%) developed serious adverse reactions unrelated to dose or dosing frequency. Due to the lack of a placebo arm and to the multiple small treatment groups, a definitive statement regarding efficacy could not be made. However, by the end of the 3-week treatment phase, daily dosing appeared more effective than weekly dosing when assessed by the number of swollen joints, the investigator and patient assessments of disease activity, pain score, and C-reactive protein levels.


These preliminary data suggest that rHuIL-1Ra may be safely administered by subcutaneous injection to RA patients. The frequency of dosing appears to be important in determining clinical response, with daily administration providing the most benefit. A placebo-controlled trial is in progress to further assess the clinical usefulness and to better define appropriate doses of rHuIL-1Ra in patients with RA.

[Indexed for MEDLINE]

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