Tocilizumab efficacy maintained for up to 2 years in RA patients
medwireNews: Patients with early rheumatoid arthritis (RA) who are treated with tocilizumab maintain the clinical benefits during their second year of treatment, analysis of phase III study data suggests.
In the FUNCTION trial, 1162 participants were randomly assigned to receive either tocilizumab at a dose of 8 mg/kg or 4 mg/kg in combination with methotrexate, tocilizumab 8 mg/kg plus placebo, or methotrexate plus placebo.
Previous analysis at the 1-year timepoint showed that rates of remission were significantly higher among patients taking tocilizumab treatment compared with methotrexate monotherapy, report study author Gerd Burmester (Charité – Universitätsmedizin Berlin, Germany) and colleagues.
After 1 year of follow-up, rates of remission were significantly higher among patients taking tocilizumab than among those taking methotrexate monotherapy.
After 2 years of follow-up, the team found that 47.6% of 290 patients treated with 8 mg/kg tocilizumab plus methotrexate were in remission according to a Disease Activity Score based on 28 joint counts and an erythrocyte sedimentation rate (DAS28-ESR) of less than 2.6 points. By comparison, 49.3% of patients in this treatment group were in remission after 1 year.
Similarly, 55.5% of participants in this group had low disease activity – defined as a DAS28-ESR score of 3.2 points or less – after 2 years, compared with 57.9% at 1 year.
And a comparable proportion of patients receiving tocilizumab 8 mg/kg alone or in combination with methotrexate achieved American College of Rheumatology (ACR) 20, 50, and 70 responses at 1 and 2 years.
These findings show that “the efficacy of [tocilizumab] was maintained for extended treatment periods,” say the researchers in the Annals of the Rheumatic Diseases.
Burmester and colleagues also found improvements in DAS28-ESR and ACR measures from the 1- to 2-year follow-up among patients who were switched to the 8 mg/kg tocilizumab plus methotrexate regimen at 1 year following poor response to methotrexate alone or in combination with 4 mg/kg tocilizumab.
However, they note that ACR response rates were lower, and the overall degree of joint damage greater, among patients who switched treatment groups compared with those receiving 8 mg/kg tocilizumab plus methotrexate throughout the study, “highlighting the importance of early initiation of therapy.”
At the 2-year follow-up, 83 serious adverse events occurred among patients receiving 8 mg/kg tocilizumab plus methotrexate, compared with 67, 58, and 31 among those in the 8 mg/kg tocilizumab plus placebo, 4 mg/kg tocilizumab plus methotrexate, and methotrexate plus placebo groups, respectively. The most frequently reported adverse events were infections in all treatment arms.
These findings were “consistent with the known [tocilizumab] safety profile,” say the researchers.
While the follow-up results of the FUNCTION trial suggest that “early [tocilizumab] therapy is a viable option for patients intolerant of [methotrexate],” the team cautions that all 2-year analyses were exploratory.
Furthermore, they stress that data for patients initially assigned to receive 4 mg/kg tocilizumab plus methotrexate or methotrexate plus placebo “should be interpreted with caution given the large number of patients switching to escape therapy.”
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