Glucocorticoid-resistant polymyalgia rheumatica: pretreatment characteristics and tocilizumab therapy

Abstract

Treatment with glucocorticoid (GC) is the preferred therapy for polymyalgia rheumatica (PMR), but some patients show poor responses to the initial GC regimen or experience flares on GC tapering. Alternative therapies for patients with GC resistance have not yet been established. To evaluate pretreatment characteristics and therapeutic outcomes of GC-resistant PMR, we followed all patients who had been diagnosed with PMR between October 2007 and February 2013, according to our standardized protocol. GC-resistant patients were defined as those who had responded poorly to the initial GC regimen (15 mg/day of prednisolone) or those who had responded to the initial regimen but had experienced a flare upon GC tapering to 5 mg/day of the maintenance dose or within the first 6 months of maintenance therapy. Out of 23 patients, nine were found to be GC-resistant cases and the others were GC responders. Baseline values of PMR activity score and its components, especially the ability to elevate the upper limbs (EUL), were significantly higher in GC-resistant patients compared with GC responders. The additional use of methotrexate (MTX, five cases), salazosulfapyridine (one case), and tocilizumab (TCZ, three cases) was effective for GC-resistant patients, although 13 to 39 weeks were required for the achievement of remission. We report the three GC-resistant cases in which TCZ was added to GC therapy with or without MTX. We also review the medical literature on the use of TCZ as of January 31, 2014 and discuss the utility of TCZ in the treatment of GC-resistant PMR.

Keywords: Glucocorticoid resistance; Interleukin-6; PMR activity score; Polymyalgia rheumatica; Tocilizumab.