SAT0655 Myositis and fasciitis by magnetic resonance imaging in recent-onset polymyalgia rheumatica and effect of tocilizumab therapy

Background In everyday practice, myofascial lesions are not usually evaluated on MRIs obtained for patients with PMR. Objectives To assess the prevalence of myofascial inflammatory lesions visible by magnetic resonance imaging (MRI) and their changes after tocilizumab therapy in active polymyalgia rheumatica (PMR). Methods We conducted a post hoc analysis of data from the TENOR study of tocilizumab monotherapy in PMR.1 The 18 patients each received tocilizumab injections at weeks 0, 4, and 8. The shoulder and pelvic girdles were assessed at baseline then at weeks 2 and 12 using T1- and T2-STIR-weighted MRI. Radiologists blinded to patient data assessed each muscle group for myositis and fasciitis on baseline, week-2, and week-12 MRIs. Reproducibility was estimated by having two radiologists assess the week-2 MRIs of 13 patients then computing the kappa coefficient. Results For myofascial lesion detection, intraobserver reproducibility was almost perfect (κ=0.890) and interobserver reproducibility was substantial (κ=0.758). At baseline, all patients had at least one inflammatory myofascial lesion (example on right shoulder fig 1); sites involved were the shoulder in 10 (71.4%) patients, hip in 13 (86.7%), ischial tuberosity in 9 (60.0%), and pubic symphysis in 12 (80.0%). Sites involved at week 12 were the shoulder in 8 (53.3%) patients, hip in 5 (33.3%), ischial tuberosity in 1, and pubic symphysis in 3 (20.0%). At week 12, of 103 muscle groups studied in all, 43 (41.7%) had no inflammatory lesions, compared to 33 at baseline (Mac Nemar; p Conclusions Myositis and fasciitis are common in recent-onset PMR and improve during tocilizumab therapy. They could be used for the diagnosis in routine practice and as criteria of outcome evaluation. References [1] Devauchelle-Pensec V, Berthelot JM, Cornec D, Renaudineau Y, Marhadour T, Jousse-Joulin S, et al. Efficacy of first-line tocilizumab therapy in early polymyalgia rheumatica: a prospective longitudinal study. Ann Rheum Dis2016;75:1506–1510. Disclosure of Interest J. P. Laporte: None declared, F. Garrigues: None declared, A. Huwart: None declared, S. Jousse-Joulin: None declared, T. Marhadour: None declared, D. Guellec: None declared, D. Cornec: None declared, V. Devauchelle-Pensec: None declared, A. Saraux Grant/research support from: Chugai, Speakers bureau: Chugai