Investigators Study Long-Term Efficacy and Safety of Tocilizumab in Patients With Giant Cell Arteritis

Temporal arteritis, light micrograph of a section of an affected vessel.
Temporal arteritis, light micrograph of a section of an affected vessel. Temporal arteritis (Horton’s disease) is a condition in which medium and large arteries, usually in the head and neck, become inflammed. The condition is one of the most common types of vasculitis, which is the general term for the inflammation of arteries and veins. The most serious complication of temporal ateritis is permanent blindness, though this can be prevented by prompt treatment with corticosteroids. The cause of the condition is unknown. It is believed to be due in part to a faulty immune response. The disorder has been linked to severe infections and the use of high doses of antibiotics. Inflammatory cell infiltrate includes macrophages, lymphocytes, plasma cells and often giant cells. The lumen is severely narrowed. Magnification: x 80 when printed at 10 centimeters wide. Human tissue.
In an open-label study of the GiACTA trial, investigators studied the long-term effect of tocilizumab in patients with giant cell arteritis.

A significant percentage of patients with giant cell arteritis (GCA) who achieved clinical remission within 12 months of weekly tocilizumab with a 6-month prednisone-tapering schedule maintained tocilizumab- and glucocorticoid-free remission for 2 years after treatment withdrawal, according to study results published in Lancet Rheumatology.

The first part of the Giant Cell Arteritis Actemra trial (GiACTA; Identifier: NCT01791153) supported the effectiveness of combined therapy with tocilizumab and a glucocorticoid taper in patients with GCA. The objective of the second part of the trial was to determine the maintenance of efficacy 1 year after tocilizumab discontinuation, the effectiveness of re-treatment with tocilizumab following relapse, and the long-term glucocorticoid-sparing effect of tocilizumab.

The current analysis (part 2 of the trial) included 215 patients who completed 52 weeks of treatment with tocilizumab or placebo in the first part of the trial. Of these participants, 44 completed 52 weeks of placebo plus a 26-week prednisone taper, 46 were assigned to receive placebo plus a 52-week prednisone taper, 85 completed treatment with tocilizumab weekly plus a 26-week prednisone taper, and 40 completed treatment with tocilizumab every alternate week plus a 26-week prednisone taper.

Among 59 of the 81 (73%) patients who achieved clinical remission within 1 year of weekly tocilizumab treatment plus a 6-month prednisone-tapering schedule, 25 patients (42%) maintained tocilizumab- and glucocorticoid-free clinical remission for another 2 years after withdrawal of GCA treatment.

Cumulative prednisone doses over 3 years were largely dictated by original treatment; those randomly assigned to receive placebo with a 52-week prednisone taper received more than twice the amount of cumulative prednisone than those who were randomly assigned to receive weekly tocilizumab (5323 vs 2647 mg, respectively; P <.05).

Patients who experienced a relapse regained remission after restarting treatment with weekly tocilizumab (median time to remission was 15 days for tocilizumab alone, 16 days for a combination of tocilizumab with prednisone, and 54 days for gluococorticoids alone).

Overall, rates of adverse events were not different between the groups and no new or unexpected safety signals were observed during the study.

Study limitations included the limited data on the safety and efficacy of continuing tocilizumab for more than a year and the changes in treatment in part 2 of the trial.

“The results of this study support the principle that continuous indefinite treatment with immunosuppressive drugs is not required to maintain disease control for all patients with [GCA],” the researchers concluded.

Disclosure: This clinical trial was supported by F Hoffmann-La Roche. Please see the original reference for a full list of authors’ disclosures.


Stone JH, Han J, Aringer M, et al; for the GiACTA investigators. Long-term effect of tocilizumab in patients with giant cell arteritis: open-label extension phase of the Giant Cell Arteritis Actemra (GiACTA) trial. Lancet Rheumatol. Published online March 19, 2021. doi:10.1016/S2665-9913(21)00038-2