Assessment of Immune Activation and Tolerance in Celiac Disease

Gluten challenge studies are used to test the effectiveness of therapies designed to prevent
immune response to gluten in participants with CeD. The study will enroll approximately 20
participants. Participants will be randomly assigned (by chance, like flipping a coin) in a
1:1 ratio to one of the two treatment groups:

- Group A: Gluten 3 gm

- Group B: Gluten 10 gm

All participants will be asked to take an oral dose of gluten at the same time on Days 1 to
14 throughout the study. This multi-center trial will be conducted in the United States. The
overall time to participate in this study is 10 weeks. Participants will visit to the clinic
on Day -45 and will be contacted for follow-up assessment on Days 15 to 42. Participants will
be followed up for video capsule endoscopy (VCE).

Inclusion Criteria:

1. Be a non-smoker who has not used tobacco- or nicotine-containing products (example,
nicotine patch) for at least 6 months before Day 1 gluten administration.

2. Have well-controlled biopsy-proven CeD, compliant with a gluten-free diet (GFD) for
greater than or equal to (>=) 6 months preceding screening, with resolution of CeD
symptoms, normalization of CeD serology, and in the judgment of the investigator, have
inactive or minimally-active disease.

3. Be HLA-DQ2.5 and/or HLA-DQ8 positive, assessed at screening. If participants have
already been genotyped, results from previous testing may be used in lieu of
genotyping at screening.

4. Be willing to delay a planned procedure involving the use of powerful electromagnetic
fields (example, magnetic resonance imaging), until the PillCam SB 3 capsule is
excreted.

5. Not undergo VCE or optical coherence tomography (OCT) if has an implanted
electromedical device or a swallowing disorder.

6. Not undergo OCT if has a contraindication to the device or procedure as per reference
information.

Exclusion Criteria:

1. Had major surgery and/or donated or lost 1 unit of blood (approximately 500 milliliter
[mL]) within 8 weeks before the first dose of gluten.

2. Are unable to refrain from or anticipate the use of any unapproved medication,
including prescription drugs, nonprescription drugs, and herbal remedies, beginning
approximately 7 days before administration of the initial dose of gluten and
continuing throughout the trial until the follow-up visit.

3. Consume excessive amounts of coffee, tea, cola, energy drinks, or other caffeinated
beverages per day. An excessive amount is defined as greater than 6 servings (1
serving is approximately equivalent to 120 mg of caffeine).

4. Have positive IgA anti-tissue transglutaminase (tTG), IgA anti-deamidated gliadin
peptide (DGP), and IgG DGP serologies at Screening.

5. Have inflammatory gastrointestinal disorders or autoimmune diseases other than CeD or
autoimmune thyroid disease.

6. Have known or suspected gastrointestinal obstructions, strictures, or fistulas based
on the clinical picture or pre-procedure testing and profile of the PillCam SB 3
capsule.

7. Endoscopy and intestinal biopsy are contraindicated.