Primary Non-Response to Tumor Necrosis Factor Antagonists is Associated with Inferior Response to Second-line Biologics in Patients with Inflammatory Bowel Diseases: A Systematic Review and Meta-analysis.

We sought to analyze whether response to a second-line biologic varies depending on the reason for discontinuation of the primary anti-TNF agent (primary non-response [PNR], secondary loss of response [LOR] after initial response, or intolerance), through a systematic review and meta-analysis.