Serum antibodies against adalimumab are associated with lower serum adalimumab concentrations and non-response to adalimumab treatment, a study has concluded.
The study, published recently in the Annals of Rheumatic Diseases, evaluated the incidence of antibody formation against adalimumab, and the link with serum adalimumab concentrations and clinical response.
The following findings were obtained from a cohort of 121 consecutive patients with rheumatoid arthritis (RA) before and up to 28 weeks after the start of treatment:
• Anti-adalimumab antibodies were detected in 21 patients (17%) during 28 weeks of treatment; nonresponders had antibodies significantly more often than good responders (34% vs 5%; p=0.032).
• Patients with antibodies showed less improvement in disease activity than patients without antibodies (mean disease activity score in 28 joints = 0.65 vs 1.70; p=0.001).
• Patients with antibodies during follow-up had lower serum adalimumab concentrations at 28 weeks than patients without antibodies (median 1.2mg/l vs 11.0mg/l, p<0.001).
• Good responders had higher serum adalimumab concentrations than moderate responders (p=0.021) and non-responders (p=0.001).
• Concomitant methotrexate use was lower in the group with anti-adalimumab antibodies than in the group without antibodies (52% vs 84%; p=0.003).
Ann Rheumat Dis 2007;66:921-6