Efficacy and safety of tocilizumab in giant cell arteritis: a single centre NHS experience using imaging (ultrasound and PET-CT) as a diagnostic and monitoring tool

Abstract

Tocilizumab (TCZ), an IL-6 receptor blocker, is approved for relapsing, refractory giant cell arteritis (GCA). We report real-life clinical experience with TCZ in GCA including assessment of responses on imaging (ultrasound (US) and 18F-Fluorodeoxyglucose Positron Emission Tomography-computed Tomography (18FDG-PET-CT)) during the first year of treatment. We included 22 consecutive patients with GCA treated with TCZ where EULAR core data set on disease activity, quality of life (QoL) and treatment-related complications were collected. Pre-TCZ US and 18FDG-PET/CT findings were available for 21 and 4 patients, respectively, where we determined the effect on US halo thickness, temporal and axillary artery Southend Halo Score and Total Vascular Score on 18FDG-PET-CT. The 22 patients with GCA (10 cranial, 10 large vessel, 2 both) had a median disease duration of 58.5 (range, 1–370) weeks prior to initiation of TCZ. Half had used prior conventional synthetic disease-modifying antirheumatic drug (csDMARDs). TCZ was initiated for refractory (50%), ischaemic (36%) or relapsing (14%) disease. Median follow-up was 43 (12–52) weeks. TCZ was discontinued due to serious adverse events (SAEs) in two patients. On treatment with TCZ, 4 discontinued prednisolone, 11 required doses ≤2.5 mg, 2 required daily dose of 2.5–5 mg and 5 needed prednisolones ≥5 mg daily. QoL improved by 50%. Total US halo thickness decreased in 38 arterial segments, median temporal artery Halo Score decreased from 11 to 0, axillary artery Halo Score remained stable. Median Total Vascular Score on FDG-PET/CT reduced from 11.5 to 6.5. In our experience, TCZ showed an excellent response with acceptable safety in GCA, with improvement on US and FDG-PET/CT imaging.

Association between the patterns of large-vessel lesions and treatment outcomes in patients with large-vessel giant cell arteritis

“…Vessel wall signals detectable by MRI (35) or vascular in ammation detectable by PET-CT (36) persisted even after the disappearance of clinical signs and symptoms. Our study also recognized elevated CRP levels without any clinical signs and symptoms as a common nding in GCA patients with aortic lesions, again emphasizing the importance of imaging in evaluating vascular in ammation (37)(38)(39)(40).…”

Need and value of targeted immunosuppressive therapy in giant cell arteritis

“…All patients in lasting remission showed MRA enhancement at follow-up, raising questions about the MRA as follow-up tool (as serum biomarkers did not indicate subclinical activity) and/or the efficiency of tocilizumab on the vascular inflammation. In a real-life, single centre study46 including GCA patients with refractory/relapsing disease treated with tocilizumab, the TA Halo Scores decreased during the follow-up, while the axillary artery Halo Score remained stable. The total vascular score on 18FDG-PET-CT also decreased.…”

One year in review 2021: systemic vasculitis

“…Given the suppression of inflammatory markers provoked by the inhibition of the interleukin (IL)-6 pathway, imaging modalities, such as CDU of temporal arteries/large vessels and 18FDG PET-CT, may play a crucial role in the follow-up of patients receiving tocilizumab. In a recent study enrolling 22 consecutive GCA patients, tocilizumab induced remission in 91% of patients, confirming its effective GC-sparing role, as well as a significant reduction of quantitative assessment of both CDU halo thickness of TA/large vessels and 18FDG PET-CT vascular uptake (44).…”