Failure of anti-TNF treatment in patients with rheumatoid arthritis: The pros and cons of the early use of alternative biological agents.

The five TNF inhibitors currently approved for the treatment of RA are characterised by differences in their molecular structures, half-lives, administration routes, dosing intervals, immunogenicity, and use in women who wish to become pregnant. TNF inhibitors still represent the first biologic after conventional synthetic DMARD (csDMARD) in the majority of patients according to registry data. This was possibly because they were historically the first biological agents available (biological DMARDS with a different mechanism of action or targeted synthetic DMARDs did not become available until 2006s), and so switching from one to another was frequent in the case of an inadequate response and/or side effects. TNF inhibitors are also efficacious for other inflammatory joint and spine diseases, and have been approved for inflammatory bowel disease, uveitis and psoriasis. In addition, national registries have provided long-term safety data and demonstrated their beneficial effect on cardiovascular morbidity and mortality. However, approximately 30-40% of patients discontinue anti-TNF treatment because of primary failure, secondary loss of response, or intolerance. The options for managing anti-TNF treatment failures include switching to an alternative anti-TNF (cycling) or to another class of targeted drug with a different mechanism of action (swapping). The aim of this review is to evaluate the pros and cons of whether it is more appropriate to choose a second anti-TNF biological agents after the failure of the first or swap treatment early.