Can IL-6 Predict Sarilumab Response?

CHICAGO—Previously, the RA-MOBILITY (NCT01061736) and SARIL-RA-MONARCH (NCT02332590) clinical trials showed that sarilumab had significantly improved efficacy when treating patients with rheumatoid arthritis (RA) compared with adalimumab and methotrexate. Recent post-hoc analyses of the trials examined if a patient’s baseline interleukin (IL) 6 levels were associated with radiographic and clinical responses to sarilumab vs. other treatments.

Presented during the 2018 ACR/ARHP Annual Meeting, the new analyses demonstrate that, at baseline, RA patients with high IL-6 levels and higher disease activity and joint damage had a better response to 200 mg of sarilumab than to methotrexate monotherapy, and adalimumab treatment in patients who had low IL-6 levels at baseline.

For the studies, baseline IL-6 levels were measured using a validated assay in patients (N=1,193) randomized to 150 mg of subcutaneous sarilumab every two weeks plus methotrexate, 200 mg of subcutaneous sarilumab every two weeks plus methotrexate, or placebo plus methotrexate. Additionally, 300 patients were randomized to 200 mg sarilumab every two weeks or 40 mg of adalimumab every two weeks. Efficacy was compared between and within treatment groups according to baseline IL-6 tertile, using linear and logistic regression.

During the MOBILITY trial, placebo plus methotrexate-treated patients in the high tertile developed more joint damage than patients in the low tertile. Sarilumab-treated patients with high IL-6 levels demonstrated improved clinical signs and symptoms and had less radiographic evidence of joint damage compared with methotrexate-monotherapy-treated patients with high IL-6 levels. In SARIL-RA-MONARCH, sarilumab-treated patients with high IL-6 levels were more likely to achieve disease remission at Week 24 compared with adalimumab-treated patients.

Data show that high IL-6 may be better than high C-reactive protein levels at predicting sarilumab efficacy outcomes in RA patients. In this study, across clinical and radiographic endpoints, patients with elevated baseline levels of IL-6 had a greater response to sarilumab treatment compared with methotrexate or adalimumab than patients with normal IL-6 levels. The authors suggest a prospective study to confirm these data.

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Michele B. Kaufman, PharmD, BCGP, is a freelance medical writer based in New York City and a pharmacist at New York Presbyterian Lower Manhattan Hospital.

Reference

1. Boyapati A, Msihid J, Schwartzman S, et al. High baseline serum IL-6 identies a subgroup of rheumatoid arthritis patients with rapid joint damage and clinical progression and predicts increased sarilumab treatment response [abstract]. Arthritis Rheumatol. 2018 Oct; 70 (suppl 10).