The drug being tested in this study is called TAK-101. TAK-101 is being tested to treat people who have celiac disease. The study has two cohorts planned. The first cohort has 1 dose level and the second cohort may include 1 or 2 dose levels, depending on safety, tolerability, and activity observed in the first cohort. Dosing in the second cohort will be based on data from the initial cohort.~The study will enrol approximately 108 patients (18 per arm). In the first cohort, approximately 45 participants will be randomly assigned in 1:2:2 ratio in one of the three arm groups which will remain undisclosed to the participant and study doctor during the study (unless there is an urgent medical need). Eligible participants in Cohort 1 will receive:~Group A: 2 infusion doses of placebo, 1 on Day 1 and 1 on Day 8, followed by 1 infusion dose of 2 mg/kg TAK-101 at Week 24.~Group B: 1 infusion dose of 2 mg/kg of TAK-101 on Day 1 followed by 1 infusion dose of placebo on Day 8, followed by 1 infusion dose of 2 mg/kg TAK-101 at Week 24.~Group C: 2 infusion doses of 2 mg/kg of TAK-101, 1 on Day 1 and 1 on Day 8, followed by 1 infusion dose of 2 mg/kg TAK-101 at Week 24.~After the review of Cohort 1 safety data, a decision will be made to either stop the study or continue the study by the sponsor safety management team (SMT), based on recommendations from independent data monitoring committee (IDMC). If it is deemed appropriate to enroll both the TAK-101 4 mg/kg and 1 mg/kg dose level, approximately 63 participants may be randomly assigned in 1:2:2:2 ratio in Cohort 2 to receive:~Group D: Two infusion doses of placebo, 1 on Day 1 and 1 on Day 8, followed by 1 infusion dose of 2 mg/kg TAK-101 at Week 24.~Group E: One infusion dose of 4 mg/kg TAK-101 on Day 1 followed by 1 infusion dose of placebo on Day 8, followed by 1 infusion dose of 4 mg/kg TAK-101 at Week 24.~Group F: Two infusion doses of 4mg/kg, 1 on Day 1 and 1 on day 8, followed by 1 infusion dose of 4 mg/kg TAK-101 at Week 24.~Group G: TAK-101 1 mg/kg: Two infusion doses of 1 mg/kg TAK-101, 1 on Day 1 and 1 on Day 8, followed by 1 infusion dose of 1 mg/kg TAK-101 at Week 24 (1 mg/kg may not be needed based on review of Cohort 1 data).~In Cohort 2 if the 1 mg/kg treatment arm is not needed, Cohort 2 will consist of 45 participants in total, being randomized in a 1:2:2 ratio to 1 of the 3 treatment groups (Groups D, E, F) listed above.~If it is decided not to open the second cohort at the 4 mg/kg dose level and if 1 mg/kg dose is recommended to be tested by the IDMC, approximately 45 participants will be randomly assigned in 1:2:2 ratio to receive:~Group D: Two infusion doses of placebo, 1 on Day 1 and 1 on Day 8, followed by 1 infusion dose of 1 mg/kg TAK-101 at Week 24.~Group E: One infusion dose of 1 mg/kg TAK-101 on Day 1 followed by 1 infusion dose of placebo on Day 8, followed by 1 infusion dose of 1 mg/kg TAK-101 at Week 24.~Group F: Two infusion doses of 1 mg/kg, 1 on Day 1 and 1 on Day 8, followed by 1 infusion dose of 1 mg/kg TAK-101 at Week 24.~This trial will be conducted in United States and Canada. The overall time to participate in this study is approximately 24 weeks. Participants will make multiple visits to the clinic, and will be contacted by telephone OR plus a final visit after receiving their last dose of study drug for a follow-up assessment.
The main aim of the study is to assess if TAK-101 can reduce gluten related symptoms and immune activation in adult participants with celiac disease (CeD) on a gluten-free diet (GFD).~Participants will receive TAK-101 and/or placebo through the vein on Day 1 and Day 8. All participants will receive active treatment at Week 24.