Efficacy of tocilizumab monotherapy after ultrashort glucocorticoid administration to treat giant cell arteritis: three year follow-up

Objectives The GUSTO (GCA treatment with Ultra-Short glucocorticoids (GC) and TOcilizumab (TCZ)) trial was set up to evaluate the efficacy and safety of a 52-week TCZ-monotherapy after a 3-day GC-pulse in new-onset GCA. The presented data show the maintenance effect of the GUSTO protocol over 3 years and the effectiveness or retreatment with TCZ after relapse. Methods Eighteen patients with newly diagnosed GCA received 500 mg methylprednisolone intravenously for 3 consecutive days followed by TCZ monotherapy from day 3 until week 52 in a single-arm, single-center, open-label clinical trial. Patients in clinical remission stopped TCZ at week 52. Maintenance of efficacy included the proportion of patients with complete lasting remission of disease at week 208. Results Median age was 72 (interquartile range 67-75) years at inclusion and 15/18 patients complained of cranial symptoms. At week 52, 13/18 patients were in relapse-free remission and entered the follow-up study. Minor relapses were observed in 2/13 patients at weeks 72, 187 and 200. In both patients, remission was achieved after restart of TCZ monotherapy. At week 208, 11/18 patients stayed in relapse-free remission; 11/13 patients remained in drug-free remission for 156 weeks. Conclusion Drug-free remission was maintained in all but two patients entering long-term extension. This relapse rate is substantially lower than reported in the randomized-controlled trials. Patient characteristics (exclusively new diagnoses), and the intensive initial treatment may explain the lasting remission.