Extended Analysis Identifies Drug-Specific Association of 2 Distinct HLA Class II Haplotypes for Development of Immunogenicity to Adalimumab and Infliximab

The global occurrence of inflammatory bowel diseases, including Crohn’s disease (CD), is rising, with prevalence of 0.5% to 1.0% reported in Europe and North America.1 Biological therapies are a mainstay of patient management, with monoclonal antibodies against tumor necrosis factor (TNF), infliximab and adalimumab, widely used as first-line agents. Highly effective in some individuals, continued use of these drugs is limited by primary nonresponse (10%–40%) or secondary immune-mediated loss of response (24%–46%) to treatment in the first year.