Tocilizumab in cranial and extracranial giant cell arteritis: a national multicenter study of 471 cases

Objective: The spectrum of giant cell arteritis (GCA) includes different vascular phenotypes. Tocilizumab (TCZ) is the only biologic currently approved regardless these phenotypes. We aimed to assess the effectiveness of TCZ in different phenotypes.

Methods: Multicentre observational study of GCA patients treated with TCZ. They were divided into three phenotypes: a) cranial (cGCA), b) extracranial (ecGCA) and c) mixed (mixGCA). Outcomes included clinical remission, EULAR complete remission, relapses, absence of inflammation in imaging techniques, and safety.

Results: We studied 471 patients (342 women; mean age 74.0 ± 9.0 years). The phenotypic distribution was: cGCA (n = 217; 46%), mixGCA (174; 37%) and ecGCA (80; 17%). Patients with ecGCA were younger (66.5 ± 10.1 years) than cGCA (74.8 ± 8.1) and mixGCA (71.4 ± 8.5), and had a longer delayed GCA diagnosis (median [IQR]) (6 [1-14] vs 1 [1-3] vs 2 [1-6] months, respectively). Systemic manifestations were similar in the 3 groups, while ischemic manifestations were more frequent in cGCA. Combined TCZ -besides glucocorticoids- was used more frequently in ecGCA (36%). Clinical remission was observed in 51%/43%/47% in cGCA/ecGCA/mixGCA, respectively, at first month, and in 79%/81%/89% at 24 months. Complete EULAR remission in 35%/27%/28% (1st month) and 72%/73%/67% (24 months).Absence of inflammation in imaging techniques was of 15%/26% (12 months) and of 22%/7% (ecGCA/mixGCA (24 months). Relevant adverse events were observed in 109 (23.1%) patients.

Conclusion: TCZ shows a rapid and maintained effectiveness in all GCA phenotypes in clinical and EULAR complete remission. By contrast, absence of inflammation in imaging techniques was much lower in ecGCA and mixGCA.