medwireNews: Phase III trial results published in The New England Journal of Medicine suggest that treatment with tocilizumab could result in sustained prednisone-free remission among patients with giant cell arteritis.
“Glucocorticoids are the mainstay of treatment because they control headaches and systemic inflammation, normalize inflammatory markers, and prevent vision loss,” say study author John Stone (Massachusetts General Hospital, Boston, USA) and colleagues.
However, long-term glucocorticoid treatment is associated with side effects, they emphasize, meaning that “treatments that are capable of maintaining the remission of giant-cell arteritis after the discontinuation of glucocorticoids would be valuable.”
In the GiACTA (Giant-Cell Arteritis Actemra) trial, 56% of 100 patients randomly assigned to receive treatment with 162 mg subcutaneous tocilizumab once weekly and 53% of 49 patients receiving the interleukin-6 inhibitor every other week, combined with a 26-week prednisone taper, had sustained remission after 52 weeks. By comparison, 14% of 50 participants treated with placebo alongside the 26-week prednisone taper had sustained remission, a significant difference.
Moreover, patients in both tocilizumab groups had a significantly higher rate of sustained remission than the 51 participants who received placebo plus a 52-week prednisone taper (56 and 53 vs 18%). Sustained remission was defined as the absence of flare and the normalization of C-reactive protein concentration to less than 1 mg/dL from week 12 to 52 and adherence to the prednisone taper.
Patients treated with tocilizumab received approximately half as much prednisone over the 52-week study period as those in the placebo groups, with a cumulative median dose of 1862 mg in both tocilizumab groups, compared with 3296 mg in patients receiving placebo with the 26-week taper, and 3818 mg in the placebo plus 52-week taper group.
A similar proportion of patients in all groups experienced adverse events, but fewer participants receiving tocilizumab weekly or every other week reported serious adverse events compared with those in the placebo plus 26-week taper or placebo plus 52-week taper groups, at 15%, 14%, 22%, and 25%, respectively. One patient receiving tocilizumab every other week experienced anterior ischemic optic neuropathy, but the resulting visual loss resolved with glucocorticoid treatment.
“It is important that clinicians treating patients with giant-cell arteritis maintain vigilance for vision complications and other disease-related events, even in patients receiving active therapy,” stress Stone and colleagues.
Taken together, the GiACTA study results “convincingly [show] that tocilizumab can result in sustained prednisone-free remissions in giant-cell arteritis over a period of 52 weeks,” and “suggest that there is an effective glucocorticoid-sparing treatment for giant-cell arteritis,” believes David Hellmann (Johns Hopkins University School of Medicine, Baltimore, Maryland, USA), the author of an accompanying editorial.
However, he concedes that “[d]espite these impressive results and the recent approval by the Food and Drug Administration for the use of subcutaneously administered tocilizumab in patients with giant-cell arteritis, additional studies are needed before tocilizumab can be recommended for all patients with active giant-cell arteritis.”
Stone and colleagues agree, noting that the planned 2-year open-label follow-up phase of the trial “may provide additional information pertaining to the safety and efficacy of tocilizumab beyond 52 weeks.
And Hellmann concludes: “I will reserve tocilizumab for patients who are at high risk for serious side effects from prednisone and for patients who have repeated flares that are not manageable with low doses of prednisone.”
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