Imaging Changes Examined in Tocilizumab-Treated Polymyalgia Rheumatica

A substantial number of patients with recent-onset polymyalgia rheumatica (PMR) treated with tocilizumab demonstrated improvements in bursitis and effusions/synovitis on magnetic resonance imaging (MRI) and ultrasound scans, according to the results of the TENOR study published in Arthritis Research & Therapy.

Researchers of the prospective, cross-sectional TENOR study (Tocilizumab Effect iN pOlymyalgia Rheumatica; ClinicalTrials.gov identifier: NCT01713842) assessed inflammatory changes with the use of MRI and ultrasound in patients receiving tocilizumab therapy for the treatment of PMR. A total of 18 patients were included in the analysis, all of whom received 3 tocilizumab infusions without corticosteroids. Ultrasound and MRI scans were performed at 0, 2, and 12 weeks. Bursitis and effusions/synovitis were scored from 0 to 3, and changes over time and correlations between ultrasound and MRI were evaluated.

At baseline, the proportion of shoulders and hips with bursitis were 93% and 100%, respectively, based on MRI scans, and 61% and 13% according to ultrasound scans. The corresponding proportion of shoulders and hips with intra-articular effusions/synovitis were 100% and 100%, respectively, based on MRI scans, and 57% and 53% according to ultrasound scans. During the first 2 weeks of treatment, imaging findings did not improve. From baseline to 12 weeks, however, bursitis improved significantly in all 4 joints by MRI (P =.005) and ultrasound (P =.029). In contrast, intra-articular effusions/synovitis improved significantly by ultrasound only (P =.001).

The proportion of abnormalities that improved by 12 weeks was 42% based on MRI findings and 37% according to ultrasound findings. MRI was able to detect bursitis in a larger proportion of hips (73% vs 13%) and ultrasound detected bursitis in a larger proportion of shoulders (57% vs 28%). In contrast, no difference was reported for intra-articular effusions/synovitis between MRI and ultrasound scans. The agreement between ultrasound and MRI findings at baseline was poor.

The investigators concluded that although both imaging techniques demonstrated improvements in bursitis and intra-articular effusions/synovitis in a considerable number of tocilizumab-treated patients, the imaging study abnormalities remained unchanged in many patients despite clinical improvements. Ultrasound may be a good imaging modality for assessing treatment response in patients with PMR because it can show complete regression of the lesions, is noninvasive, and is widely available.

Reference

Huwart A, Garrigues F, Jousse-Joulin S, et al.  Ultrasonography and magnetic resonance imaging changes in patients with polymyalgia rheumatica treated by tocilizumab. Arthritis Res Ther. 2018;20(1):11.