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17-01-2019 | Rheumatology | News | Article

Real-world data support tocilizumab use in GCA patients

medwireNews: Tocilizumab treatment results in a “rapid and maintained” clinical improvement among patients with giant cell arteritis (GCA) in routine clinical practice, researchers report.

Ricardo Blanco (Universidad de Cantabria, Santander, Spain) and study co-authors say that their findings “are consistent with those observed in clinical trials, confirming the efficacy of [tocilizumab] in the treatment of GCA”, but stress that rates of serious infection in a real-world setting “appear to be higher than in clinical trials.”

The retrospective study included 134 GCA patients aged an average of 73 years who initiated treatment with the interleukin (IL)-6 receptor inhibitor as a result of refractory disease (64%) or unacceptable side-effects of previous treatment (36%).

Tocilizumab therapy was started after a median of 13.5 months following GCA diagnosis; the initial dose was 8 mg/kg every 4 weeks for the 106 patients given intravenous tocilizumab, and 162 mg/week for the 28 patients taking the subcutaneous form, while the maintenance doses ranged from 4 mg/kg every 8 weeks to 8 mg/kg every 4 weeks and from 162 mg every 3 weeks to 162 mg/week, respectively.

A total of 96.2% of patients were taking corticosteroids at the time of starting tocilizumab, while 73.1% had previously received treatment with traditional DMARDs, most commonly methotrexate. The most commonly reported clinical features of GCA prior to tocilizumab initiation were polymyalgia rheumatica and headache, occurring in 73 and 70 patients, respectively, followed by constitutional symptoms (n=31) and jaw claudication (n=14).

The team found that 93.9% of patients experienced improvement in clinical features of GCA at the 1-month follow-up after initiating tocilizumab treatment, as did 90.9% of 99 patients with available data at the 6-month follow-up and 100% of 39 patients at the 2-year follow-up.

Clinical improvements were accompanied by a significant decrease in median C-reactive protein levels, which fell from 1.7 mg/dL at baseline to 0.11 mg/dL after 1 month of tocilizumab treatment, 0.09 mg/dL at 6 months and 0.10 mg/dL at 2 years, as well as a significant fall in median erythrocyte sedimentation levels from 33 to 6 mm/1st hour over 2 years.

Tocilizumab treatment was also associated with a reduction in corticosteroid use, say the researchers, with the median prednisone dose decreasing from 15.00 mg/day at baseline to 13.75, 5.00 and 0.00 mg/day at the 1, 6 and 24-month follow-up times, respectively.

In subgroup analyses, the researchers demonstrated that similar improvements in clinical features and acute phase reactants occurred when patients were stratified according to disease duration prior to tocilizumab treatment (≤ vs > 6 months), the route of tocilizumab administration (intravenous vs subcutaneous) and the dose given (≤ vs > 15 mg/day).

Therefore, tocilizumab “seems to be an excellent therapeutic option in GCA, regardless of the administration route and GCA duration, helping to minimize the glucocorticoid exposure over time”, write the study authors in Seminars in Arthritis and Rheumatism.

A total of 23.9% (n=32) of patients experienced adverse events during a median follow-up of 12 months, and 17 patients permanently discontinued tocilizumab. In all, 16 patients developed serious infections, translating into a serious infection rate of 10.6 per 100 patient–years, which the researchers note was higher than that reported in the GiACTA trial.

By Claire Barnard

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