Tocilizumab monotherapy for polymyalgia rheumatica: A prospective, single-center, open-label study

Objectives Polymyalgia rheumatica (PMR) is a systemic inflammatory disease in the elderly of unknown etiology. While glucocorticoids are the mainstay of treatment for PMR, various glucocorticoid-related adverse events are common. Recently, several studies have reported the efficacy of tocilizumab (TCZ), an anti-interleukin-6 receptor antibody, for PMR treatment in addition to an accompanying reduction, or even tapering-off, of glucocorticoids in some cases. The objective of this study was to elucidate the efficacy of TCZ monotherapy in the absence of glucocorticoids for PMR. Method We conducted a 2-year, prospective, single-center, open-label pilot study of TCZ monotherapy in patients with PMR. TCZ (8 mg/kg) was administered at fortnightly intervals for the first 2 months and monthly over the next 10 months. Subsequently, patients were observed for another year without any treatment. The primary endpoints were the remission rates at weeks 12 and 52, and the secondary endpoints were the relapse rate and safety over the total 104 weeks. Results Thirteen patients were included in this study. Four of these patients achieved remission at week 12 (remission rate 31%). Four patients withdrew from the study due to adverse events (n = 2) and inefficacy (n = 2). At week 52, all 9 patients who had completed the first year achieved remission. Eight patients completed the drug-free second year, with 7 maintaining remission. Conclusions TCZ monotherapy is well tolerated and can lead to remission in most patients with PMR in the absence of glucocorticoids.