Secondary analyses demonstrated that, at week 52, more patients treated with tocilizumab were relapse free while tapering to prednisone ≤5 mg/d (81% vs. 56%). However, by week 78, approximately equal numbers of patients in both groups met this criterion (50% vs. 58%).
For patients with GCA treated with glucocorticoids for one year, we expect to see a relapse rate of approximately 50%. This subgroup analysis implies that patients treated with methotrexate experience many of these relapses upfront, whereas patients treated with tocilizumab do not begin to relapse in earnest until after they stop tocilizumab therapy.
This study does not address whether methotrexate may be more effective as a remission-maintenance agent, following remission induction with tocilizumab.7 However, for those of us who have used methotrexate as a safe alternative to tocilizumab for remission induction in patients with GCA, methotrexate’s association with Pneumocystis infection and increased mortality is foreboding.
4. Vascular Ultrasound in GCA
Ni et al, Abstract 27028
Vascular ultrasound is becoming increasingly popular as an alternative to temporal artery biopsy for diagnosing GCA. However, the majority of data supporting its use was generated by physicians who performed the ultrasound themselves. The current study examined the efficacy of vascular ultrasound when performed by radiology technicians.
In the study, 581 patients underwent vascular ultrasound; 80 of these patients (21.3%) had a confirmed clinical diagnosis of GCA after six months of follow-up. Using a clinical diagnosis of GCA as the gold standard, vascular ultrasound had a sensitivity of 21.3% and a specificity of 100%. The negative predictive value of vascular ultrasound was 82.4%.
When performed by an experienced clinician, vascular ultrasound has a sensitivity approaching temporal artery biopsy. However, the same cannot be said when the test is performed by a vascular ultrasound technician who may not have specific training in the assessment of GCA. Carotid arteries are assessed mainly based on flow dynamics, which are not useful when trying to determine if a patient has an inflamed temporal artery.
For years, rheumatologists have known that musculoskeletal ultrasound is most effective when performed by a clinician who understands the underlying disease and its pathology. It shouldn’t be surprising to learn that the same is true for temporal artery ultrasound.
5. Glucocorticoids vs. Glucocorticoids Plus Tocilizumab
De Boysson et al., Abstract 27049
Patients with GCA may have histopathologic evidence of arterial inflammation years after treatment initiation. Such patients are at higher risk of developing potentially life-threatening aneurysms.10 However, whether some therapies are more effective at extinguishing this chronic arterial inflammation has remained unclear.
