A Study of TAK-062 in Treatment of Active Celiac Disease in Participants Attempting a Gluten-Free Diet

Inclusion Criteria:

1. Has an adequate comprehension of a gluten-free diet (GFD) assessed by the siteinvestigator after review of responses to a knowledge test. The final determinationof a participant's adequate comprehension of a GFD is at the discretion of theinvestigator.

2. Has at least 1 CeD-related GI symptom of moderate or greater severity, as measuredby the CDSD, on at least 3 days out of any consecutive 7-day period during thescreening period (Week -8 visit until Week -4 visit), felt by the investigator to berelated to gluten exposure. The CeD-related symptom(s) may vary day by day as longas the severity of at least 1 symptom is moderate or greater. The participants mustmeet symptom criteria to undergo esophagogastroduodenoscopy (EGD)/video capsuleendoscopy (VCE).

3. Has been attempting to maintain a GFD for at least 12 months as self-reported by theparticipant.

4. Has small intestinal villous atrophy on duodenal biopsy defined as Vh:Cd <2.5 atWeek -4.

5. The participant is human leukocyte antigen (HLA)-DQ2 and/or HLA-DQ8 positive.

6. The participant is in a good general state of health according to clinical historyand physical examination, in the opinion of the investigator.

7. Have a body mass index (BMI) between 16 and 45 kilogram per meter square (kg/m^2),inclusive. Note: Individuals with BMI of 40 to 45 should be discussed with the medical monitorand confirmed to be appropriate for endoscopy according to local site guidelines.

8. The participant is willing and able to continue any current dietary and/or medicalregimens (including gastric acid suppression) in effect at the first visit (Visit 1).

There should be no changes to diet, medications (prescription or over-the-counter) or supplements during study participation.

Exclusion Criteria:

1. Has the presence of other inflammatory GI disorders or systemic autoimmune diseasesthat either have the potential to cause persistent GI symptoms similar to CeD or arenot well controlled without the use of excluded medication.

• Examples of conditions that are exclusionary include inflammatory boweldisease, eosinophilic esophagitis, gastroenteritis or colitis, microscopiccolitis diagnosed at screening or requiring treatment in the 6 months beforescreening.

• Examples of conditions that may be permissible after discussion with themedical monitor include systemic autoimmune disease such as scleroderma,psoriatic or rheumatoid arthritis, or lupus that is stable and without GIinvolvement; well controlled autoimmune thyroid disease; well-controlled type 1diabetes; or proton pump inhibitor (PPI) responsive eosinophilic esophagitis insymptomatic and histologically confirmed remission.

2. Has ongoing systemic immunosuppressant, systemic corticosteroid treatment excludingmedication given for the endoscopies, or treatment with systemic immunosuppressantsor systemic corticosteroids in the 12 weeks before Screening.

• The participant is receiving immunosuppressive doses of corticosteroids: 3 mg perday or more of budesonide for more than 3 consecutive days within 3 months beforeScreening, more than 20 mg of prednisone given daily or on alternative days for 2weeks or more within 90 days before the first dose, any dose of oral or intravenous (IV) corticosteroids within 30 days of the first dose, or high-dose inhaledcorticosteroids (>960 micrograms per day [μg/day] of beclomethasone dipropionate orequivalent), or other systemic immunosuppressive agents.

3. Has ongoing use of over-the-counter digestive enzymes or digestive supplements,other than lactase, including those for gluten digestion. Probiotics are allowableif they were started before Screening and not discontinued or changed in dose ortype during the study.

4. Has completed the CDSD on ≤75% of the evaluable days during the run-in period untilrandomization.

5. Has active microscopic colitis requiring treatment in the 6 months before Screening.

• Microscopic colitis detected at screening if sigmoidoscopy is performed wouldexclude the participant.

6. Has known or suspected type 2 refractory CeD or ulcerative jejunitis.

7. Has ongoing chronic use (defined as >7 days continuous use) of a nonsteroidalanti-inflammatory drug aside from <100 mg aspirin, daily, for prophylactic use.

8. Has ongoing use, or use in the 3 months before screening, of medications known tocause villous abnormalities (e.g., mycophenolate mofetil, angiotensin receptorblockers, colchicine).

9. Has used treatments for GI symptoms including antiemetics, antidiarrheals,antispasmodics, medical marijuana, (use of medical marijuana indicated for non-GIconditions is not exclusionary) within 2 weeks of Screening and during the run-inperiod. Participants on stable dose (i.e., more than 4 weeks) of an osmotic,bulking-forming or emollient (surface active agent) laxative are eligible, providedsymptoms are considered not related to CeD in the opinion of the investigator.

10. Has a known or suspected severe enteric infection (viral, bacterial, or parasitic)within 6 months before randomization. Severe enteric infection is defined asrequiring emergency room visit or hospitalization or treatment with antibiotics oranti-infectives due to infection. Non enteric viral infections, either resolved orwell-controlled are not exclusionary.

11. Has a contraindication to endoscopy with duodenal biopsy.

--Contraindication to VCE (strictures, anastomoses, etc) is not an exclusion if theparticipant is able to complete the other aspects of the study.

12. Has additional food allergies (tapioca syrup, oats, almonds, rice crisp, chocolate,almond, butter, wheat gluten, cocoa butter, oat flour, glycerin, sunflower lecithin,salt, and natural flavors) to nongluten ingredients in the SIGE bar study food orsignificant symptoms upon ingestion of the gluten-free SIGE bar during screening.

13. Has a history of intolerance, hypersensitivity, or idiosyncratic reaction to anaminoglycoside.

14. Has a known human immunodeficiency virus (HIV) infection or positive tests forhepatitis B or C. The participant has a known clinically significant chronicallyactive hepatopathy of any origin, including cirrhosis, and participants withpersistent positive hepatitis B virus surface antigen and quantitative hepatitis Bvirus polymerase chain reaction (PCR), or positive serology for hepatitis C virus (HCV) and quantitative HCV PCR within 6 months before the screening visit.

15. Is positive for severe acute respiratory syndrome coronavirus 2 at the time ofscreening and exhibits symptoms that, in the opinion of the investigator, mayinterfere with study compliance, completion, or accurate assessment of studyoutcomes or safety.

16. Has a known hypersensitivity reaction and/or allergy, including anaphylaxis, towheat and/or gluten.

17. Has known history of hypersensitivity, idiosyncratic reaction, or intolerance to anyingredients or excipients in TAK-062 and/or placebo.

18. The participant has a current diagnosis of active malignancy or is receivingtreatment for active malignancy (hormone therapy alone is not exclusionary).Participants with fully resected Stage 0 (carcinoma in situ) or Stage 1 tumorwithout signs of recurrence may participate. All other individuals with malignanciesdiagnosed in the 5 years prior to screening are excluded.

Region-specific Exclusion Criteria:

18. Participant enrolling in a study in France is not affiliated to a social securityscheme or a beneficiary of such a scheme.

19. Participant enrolling in a study in France is deprived of their liberty by ajudicial or administrative decision.