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ACR CONVERGENCE 2021—Tocilizumab (Actemra) is a recombinant humanized monoclonal antibody of the interleukin (IL) 6 receptor that inhibits IL-6-mediated signaling.1 IL-6 is a key player in immune and inflammatory responses. Recent research evaluated the incidence and risk factors for flares after switching patients with rheumatoid arthritis (RA) who were stable on intravenous (IV) tocilizumab therapy to subcutaneous tocilizumab. Soo Min Ahn, MD, from the Asan Medical Center, Seoul, South Korea, presented these data during ACR Convergence 2021, held Nov. 3–9.2
Background: On Jan. 8, 2010, the U.S. Food & Drug Administration (FDA) approved tocilizumab in an intravenous injection to treat adults with moderate to severe active RA for whom one or more tumor necrosis factor antagonists have proved inadequate.3 On Oct. 21, 2013, a subcutaneous form of tocilizumab was approved. Current FDA-approved indications for tocilizumab include RA, giant cell arteritis, systemic sclerosis-associated interstitial lung disease, polyarticular juvenile idiopathic arthritis and cytokine release syndrome.4 Tocilizumab is also approved throughout the world for numerous indications.
Dr. Ahn and colleagues retrospectively evaluated the incidence of RA flares in patients from a single tertiary hospital who had switched from IV tocilizumab to subcutaneous tocilizumab between January 2013 and April 2020. The patients were divided into two groups—the subcutaneous-inefficacy group and the subcutaneous-efficacy group—based on their RA Disease Activity Score in 28 joints (DAS28) after switching to subcutaneous tocilizumab. Factors associated with RA flares were evaluated by multivariate analysis.
The Results
Researchers identified 147 patients who were initially treated with IV tocilizumab and subsequently achieved remission or low disease activity. Of these patients, 37 were switched to subcutaneous tocilizumab. At the time of switching, the mean DAS28 did not differ between the two groups (2.46 for the subcutaneous-inefficacy group vs. 2.17 for the subcutaneous-efficacy group). The subcutaneous-inefficacy group had 11 patients (29.7%), all women, and the subcutaneous-efficacy group had 26 patients (70.3%), 81% of whom were women (n=21). The median disease duration of patients in the subcutaneous-efficacy group was 138 months (36–160) and 92 months (51–181) in the subcutaneous-efficacy group. IV tocilizumab doses per weight and methotrexate doses were higher in the subcutaneous-inefficacy group.
In the multivariate analysis, the use of more than 8 mg/kg tocilizumab, which is considered a high dose, non-use of methotrexate and a history of prior abatacept treatment were associated with the risk of RA flares after switching to subcutaneous tocilizumab.
These study results led the authors to recommend clinicians examine these factors prior to switching patients from IV tocilizumab to subcutaneous tocilizumab to prevent RA flares.
