Temporal ultrasound for monitoring tocilizumab treatment in giant cell arteritis: seeing beyond serum markers?

Tocilizumab in giant cell arteritis: an update for the clinician

PURPOSE OF REVIEW

The recent approval of tocilizumab (TCZ) for the treatment of giant cell arteritis (GCA) has changed the landscape for management of this disease. Herein, we review recent literature addressing practical questions for the clinician regarding the use of TCZ in GCA. We evaluate efficacy of TCZ across different disease phenotypes, optimal dosing and formulation, treatment-related toxicity, recommendations for monitoring disease, and duration of therapy.

RECENT FINDINGS

Post-hoc analyses of a large clinical trial and real-world data suggest efficacy of TCZ across various disease phenotypes in GCA, and support use of weekly subcutaneous dosing over every-other-week dosing. More data are needed to guide duration of TCZ therapy, optimal disease activity monitoring in patients treated with TCZ, and to speak to efficacy in GCA with large vessel involvement.

SUMMARY

TCZ has added valuably to the treatment arsenal in GCA, though more data are needed to guide optimal use of the drug.

Ultrasound halo sign as a potential monitoring tool for patients with giant cell arteritis: a prospective analysis

OBJECTIVES

To assess the sensitivity to change of ultrasound halo features and their association with disease activity and glucocorticoid (GC) treatment in patients with newly diagnosed giant cell arteritis (GCA).

METHODS

Prospective study of patients with ultrasound-confirmed GCA who underwent serial ultrasound assessments of the temporal artery (TA) and axillary artery (AX) at fixed time points. The number of segments with halo and maximum halo intima-media thickness (IMT) was recorded. Time points in which >80% of patients were assessed were considered for analysis. Halo features at disease presentation and first relapse were compared.

RESULTS

49 patients were assessed at 354 visits. Halo sensitivity to change was assessed at weeks 1, 3, 6, 12 and 24 and showed a significant standardised mean difference between all time points and baseline for the TA halo features but only after week 6 for the AX halo features. The number of TA segments with halo and sum and maximum TA halo IMT showed a significant correlation with erythrocyte sedimentation rate (0.41, 0.44 and 0.48), C reactive protein (0.34, 0.39 and 0.41), Birmingham Vasculitis Activity Score (0.29, 0.36 and 0.35) and GC cumulative dose (-0.34, -0.37 and -0.32); no significant correlation was found for the AX halo features. Halo sign was present in 94% of first disease relapses but with a lower mean number of segments with halo and sum of halo IMT compared with disease onset (2.93±1.59 mm vs 4.85±1.51 mm, p=0.0012; 2.01±1.13 mm vs 4.49±1.95 mm, p=0.0012).

CONCLUSIONS

Ultrasound is a useful imaging tool to assess disease activity and response to treatment in patients with GCA.

Recent advances in the diagnosis and management of giant cell arteritis

PURPOSE OF REVIEW

Giant cell arteritis (GCA) has classically been diagnosed by temporal artery biopsy and treated with high-dose, long-term glucocorticoid therapy. Noninvasive imaging increasingly is employed for diagnostic purposes, but further studies are needed to determine the role of imaging in monitoring longitudinal disease activity. Glucocorticoid-sparing therapy mitigates the numerous adverse effects of glucocorticoids. This review addresses new developments in these areas.

RECENT FINDINGS

For diagnosis, when performed at a center with expertise in its use, temporal artery ultrasound has an estimated sensitivity and specificity of 78 and 79%, respectively. State-of-the-art time-of-flight positron emission tomography/computed tomography (PET/CT) has an estimated sensitivity and specificity of 71 and 91%, respectively. The sensitivities of both imaging modalities decrease following glucocorticoid administration. Tocilizumab is an effective glucocorticoid-sparing therapy, demonstrating sustained glucocorticoid-free remission in 56% of patients receiving weekly tocilizumab compared with 18% of patients receiving a 52-week prednisone taper. The traditional acute phase reactants are of no value in patients treated with interleukin-6 receptor (IL6-R) blockade, and thus, the development of new biomarkers is an important priority in the field.

SUMMARY

Noninvasive imaging techniques are increasingly used in the absence of temporal artery biopsy to confirm diagnostic suspicions of GCA. Tocilizumab reduces the cumulative glucocorticoid exposure and increases the rate of sustained remission. Ongoing efforts are directed towards new methods to identify disease flares.

[Long-term complications, monitoring and interventional treatment of large vessel vasculitis]

Giant cell arteritis (GCA) and Takayasu's arteritis (TAK) both belong to the group of large vessel vasculitides and require long-term drug treatment. Glucocorticoids (GC) are the first choice for the treatment of both diseases. For GCA immunosuppressants, such as tocilizumab or methotrexate should be considered in cases of treatment refractory and relapses or if there is a high risk for GC-related adverse events. In TAK patients the use of immunosuppressive agents should be considered for all patients. In the course of the disease, severe disease-associated and treatment-associated complications can occur. The most frequent disease-associated complications include visual impairment up to blindness in GCA, as well as vascular stenoses with ischemia and aortic aneurysms with possible dissection in GCA and TAK. Percutaneous transluminal angioplasty (PTA) and stenting are minimally invasive, low-risk interventional procedures for GCA and TAK patients with clinically significant vascular stenoses, despite a tendency to restenosis. Interventional procedures should be weighed up against vascular surgical approaches depending on the localization and the total clinical situation. All interventions should be conducted in a phase of stable remission when possible. For monitoring of disease activity in patients with GCA and TAK, assessment of clinical manifestations as well as C‑reactive protein (CRP) and the erythrocyte sedimentation rate (ESR) are useful; however, both are unreliable under interleukin‑6 block with tocilizumab. The value of new biomarkers independent from interleukin‑6 and the importance of imaging (sonography, magnetic resonance angiography, computed tomography and positron emission tomography-CT) for monitoring GCA and TAK still have to be investigated in future studies.