This study tests a drug called TAK-101 for people with celiac disease, which is an illness where eating gluten (a protein found in wheat, rye, and barley) causes the immune system to attack the body. The study checks if TAK-101 can help reduce symptoms related to gluten and the body's immune response in adults who are on a gluten-free diet. Participants will receive TAK-101 or a placebo (a substance with no active drug) through an infusion (medicine given directly into the blood) on Day 1 and Day 8. Everyone gets the active treatment at Week 24.

• The study lasts about 34 weeks, with several clinic visits and phone check-ins.
• Participants will be divided into groups and may receive different dose levels.
• Approximately 90 people will join the study, with some getting TAK-101 and others getting a placebo.

Eligible participants must have confirmed celiac disease and follow a gluten-free diet for at least six months. People cannot join if they have other gut-related issues or have had TAK-101 before. The study is global, aiming to find a safe and effective way to help those with celiac disease.