HLA-DQA1*05:01 and DQA1*05:05 inform choice of anti-tumor necrosis factor and concomitant use of immunomodulators in patients with inflammatory bowel disease

Abstract

Background and Aims Loss of response (LoR) is a major limitation of anti-tumor necrosis factor (anti-TNF) therapy in inflammatory bowel disease (IBD). It can result from immunogenicity or other, less well-defined mechanisms. Specific HLA alleles have been linked to immunogenicity, but their association with LoR are not fully understood. In this study, we aimed to assess the relationship between HLA alleles and LoR, and investigate the impact of concomitant immunomodulator use. Methods LoR and sustained response to infliximab or adalimumab were defined in 25642 IBD patients from the IBD BioResource. We applied multivariable Cox proportional hazards models to assess the effect of HLA alleles on time to LoR. The effect of concomitant immunomodulator use was also evaluated. Significantly associated alleles were further tested in patients treated with ustekinumab and vedolizumab. Results HLA-DQA1*05:01 was associated with reduced time to LoR in infliximab-treated patients (P=5.34E-07), while HLA-DQA1*05:05 was associated with reduced time to LoR in adalimumab-treated patients (P=3.20E-05). Neither allele was associated with LoR to ustekinumab or vedolizumab. Concomitant use of immunomodulators conferred a protective effect against LoR to infliximab and adalimumab in carriers of HLA-DQA1*05:01 and HLA-DQA1*05:05, respectively. However, this protective effect was not observed in adalimumab-treated patients who carried neither allele subtype (P=.11). Conclusions Our findings highlight distinct associations between HLA-DQA1*05 allele subtypes and time to LoR of infliximab and adalimumab in IBD-treated patients. The protective effect of immunomodulator use is allele-specific for adalimumab. These results provide a rationale for incorporating HLA testing into personalized anti-TNF management to optimize treatment durability.