Phase 1 and phase 2a study designs. (A) Phase 1 safety study (n = 23): Part A (single ascending intravenous doses of TAK-101, n = 17) followed by Part B (2 ascending intravenous doses administered on days 1 and 8, n = 6) assessed the safety, tolerability, and pharmacokinetics of TAK-101 and established the dose to be used in the phase 2a study. (B) Phase 2a proof-of-concept study (n = 34) in patients infused with placebo or TAK-101, 8 mg/kg, on days 1 and 8. All patients underwent a 14-day oral GC beginning on day 15 consisting of 12 g/d for the first 3 days and 6 g/d for the following 11 days. BL, baseline; GC, gluten challenge. aDay 29 was equivalent to 1 day after the 14-day gluten challenge.