Kennedy NA, et al. - Because anti-TNF drugs are efficacious for managing Crohn's disease, but treatment failure is common, researchers identified clinical and pharmacokinetic factors predicting primary non-response at week 14 after initiation of treatment, non-remission at week 54, and adverse drug withdrawal events. At the time of initial exposure to infliximab or adalimumab, anti-TNF-naive patients (aged ≥6 years) with active luminal Crohn's disease were enrolled between March 7, 2013, and July 15, 2016. Nine hundred fifty-five patients treated with infliximab and 655 treated with adalimumab were enrolled in this personalised anti-TNF therapy in Crohn's disease study (PANTS), a prospective observational UK-wide study. Data reported that the proportion of patients who developed anti-drug antibodies (immunogenicity) was 62·8% for infliximab and 28·5% for adalimumab. Investigators found that the failure of anti-TNF therapy is common and is predicted by low concentrations of drugs, partially mediated by immunogenicity. Clinical trials are required to examine whether personalized induction regimens and intensification of treatment-to-target dose improve results.