- Primary non-response to Adalimumab induction (160mg at week 0, 80 mg at week 2, then 40 mg every 2 weeks: q2w), defined as CDAI ≥ 220 in combination with C-Reactive Protein (CRP) ≥ 0.5mg/dl or endoscopic or radiological evidence of disease activity and evaluated 2 weeks after 6 injections (q2w) of Adalimumab (injections week 0 to week 10, evaluation week 12). OR Loss of response to Adalimumab, defined as CDAI ≥ 220 in combination with CRP ≥ 0.5mg/dl or endoscopic or radiological evidence of disease activity and after at least 4 weeks of weekly injections of Adalimumab (40mg).