Temporal ultrasound may be an “appealing choice” for disease activity monitoring in tocilizumab-treated patients with cranial giant cell arteritis (GCA), according to a letter published in the Annals of the Rheumatic Diseases.1

In the correspondence, researchers shared their experiences with GCA; they discussed the 2 known subtypes, cranial GCA and large-vessel GCA, and noted that, within the last year, temporal arterial ultrasound was being increasingly recognized as a first-line diagnostic tool for cranial GCA. At the same time, magnetic resonance angiographic and 18-fluorodeoxyglucose positron emission tomography (FDG-PET) was utilized for large-vessel GCA.

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According to the researchers, tocilizumab, in addition to corticosteroids, demonstrated efficacy leading to disease remission, faster steroid sparing, and reduced relapse rate. However, disease flares occurred in tocilizumab-treated patients after discontinuation.  


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“Due to the lack of [a] reliable [serologic] marker for these patients, imaging modalities emerge as possible monitoring and prognostic tools,” the researchers wrote, adding that repeated biopsies to monitor disease were not clinically feasible.

For cranial GCA, FDG-PET has a high cost and low availability, compared with the low cost and general availability of ultrasound, which is also a radiation-free option with acceptable sensitivity in terms of vessel wall inflammation detection. Based on these reasons, the researchers wrote that “serial [ultrasound] examinations might be useful for the monitoring of [tocilizumab] treatment.”

However, experiences of using temporal ultrasound to monitor tocilizumab-treated patients with cranial GCA has been limited; only 2 cases reported the disappearance of the “halo sign” after tocilizumab therapy initiation.2 In the researchers’ clinic, tocilizumab therapy led to “significant amelioration” of vessel wall inflammation in 2 cases: a 62-year-old woman and an 85-year-old woman, both with cranial GCA. In both cases, the hypoechoic appearance of the vessel wall decreased after tocilizumab initiation and was successfully monitored by temporal ultrasound.

According to the researchers, for large-vessel GCA, contrast-enhanced ultrasound may detect disease flares in tocilizumab-treated patients with Takayasu arteritis, but the study of the technique remains limited and the use of ultrasound for monitoring disease activity is still under debate. Among patients with large-vessel GCA, FDG-PET monitoring may be most useful.

“Awaiting further prospective studies, we suggest that temporal ultrasound can be an appealing choice for monitoring disease activity in cranial GCA patients treated with [tocilizumab],” the researchers concluded.

References

1. Evangelatos G, Fragoulis GE, Iliopoulos A. Temporal ultrasound for monitoring tocilizumab treatment in giant cell arteritis: seeing beyond serum markers? [published online November 5, 2019]. Ann Rheum Dis. doi:10.1136/annrheumdis-2019-216527

2. Vitiello G, Battaglini Orsi C, Carli G, et al. Tocilizumab in giant cell arteritis: a real-life retrospective study. Angiology. 2018;69(9):763-769.