Treatment of giant cell arteritis with ultra-short glucocorticoids and tocilizumab: results from the extension of the TOPAZIO study.

Objectives: To assess the maintenance of efficacy of one year of tocilizumab (TCZ) monotherapy after its discontinuation in large vessel-GCA (LV-GCA).

Methods: 17 patients with active LV-GCA were previously treated with 3 boluses of intravenous methylprednisone and weekly subcutaneous TCZ in monotherapy for 52 weeks. Patients in relapse-free clinical remission at week 52 discontinued TCZ and entered part two, which was a 26-week observational follow-up period. PET/CT was performed in all patients at the end of the 26-week observational period (week 78). End points were the variation in PET vascular activity score (PETVAS) at week 78 compared with baseline and with week 52, and the proportion of patients with relapse-free clinical remission at week 78 and at the end of the follow-up.

Results: Compared with baseline, a significant reduction in PETVAS was observed at week 78, mean (95% CI) change -6.6 (-9.5 to -3.7). However, compared with week 52, PETVAS significantly increase 6 months after TCZ discontinuation (week 78), mean (95% CI) change 4.6 (0.7-8.5). The proportion of patients with relapse-free clinical remission at weeks 78 and at the end of the follow-up (median time from TCZ discontinuation 148 weeks) was 11/17 (65%, 95% CI 38-86) and 8/17 (47%, 95% CI 23-72), respectively. Age and sex-adjusted HR (95% CI) for each unit increase of PETVAS indicating subsequent relapse was 1.36 (0.92-2.00).

Conclusions: One year of TCZ monotherapy was effective in maintaining drug-free clinical remission in LV-GCA. Changes in PETVAS early after TCZ discontinuation may predict subsequent relapses.

Clinical Trial Registration: ClinicalTrials.gov, NCT05394909.