The primary objectives are:

• Characterize the T cell receptor (TCR) repertoire in duodenal biopsy samples of participants pre- and post-challenge.
• Compare for each patient the TCR repertoire of duodenal biopsy samples with the peripheral blood TCR repertoire of each study participant
• Characterize the transcriptome of duodenal biopsy samples and blood from study participants pre- and post-challenge

The secondary objectives are:

• Ex vivo identification and validation of DQ-restricted gliadin specific TCRs.
• Characterize the gluten-challenge induced changes in small intestine histology using standard for Celiac Disease (CeD) histological assessments

Key Inclusion Criteria:

1. Have a body mass index (BMI) ≥17 and ≤40 kg/m2 and a body weight >45 kg at the Screening Visit
2. Be judged to be in good health as defined in the protocol
3. Have well-controlled biopsy-proven CeD, compliant with a GFD for ≥6 months preceding Screening as defined in the protocol
4. Be HLA-DQ2 and/or HLA-DQ8 positive as defined in the protocol

Key Exclusion Criteria:

1. Have a history of gluten triggered acute symptoms (≤24 hours after gluten exposure), and/or severe symptoms (abdominal pain interfering with daily activities, diarrhea with >5 stools/day), and/or prolonged symptoms (duration >7 days)
2. Have a history of clinically significant endocrine, cardiovascular, hematological, hepatic, immunological (other than CeD or autoimmune thyroid disease), renal, respiratory, genitourinary, or major neurological (including stroke and chronic seizures) abnormalities or disease
3. Have participated in another investigational trial within 4 weeks before Screening
4. Have a history of cancer (malignancy) other than nonmelanoma skin cancer
5. Have a history of significant multiple and/or severe allergies (e.g., latex allergy)
6. Presence of HIV (HIV Ab), hepatitis B (HBsAg, HBAb) or Hepatitis C (HCV Ab) seropositivity at screening
7. Ongoing immunosuppression or receive any treatment that might alter T cell repertoire or phenotype

Note: Other protocol-defined inclusion/ exclusion criteria apply

All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing

When Regeneron has received marketing authorization from major health authorities (e.g., FDA, European Medicines Agency (EMA), Pharmaceuticals and Medical Devices Agency (PMDA), etc.) for the product and indication, has made the study results publicly available (e.g., scientific publication, scientific conference, clinical trial registry), has the legal authority to share the data, and has ensured the ability to protect participant privacy.

Qualified researchers can submit a proposal for access to individual patient or aggregate level data from a Regeneron-sponsored clinical trial through Vivli. Regeneron's Independent Research Request Evaluation Criteria can be found at: https://www.regeneron.com/sites/default/files/Regeneron-External-Data-Sharing-Policy-and-Independent-Research-Request-Evaluation-Criteria.pdf