Study of DONQ52 in Active Celiac Disease

Inclusion Criteria: * Body mass index (BMI) of 18 to 40 (kg/m2) at screening. * Willingness to ingest a gluten-free product and Simulated Inadvertent Gluten Exposure (SIGE) products as per the study protocol. * History of medically diagnosed, and adequately documented (i.e., included in the participant's medical records), CeD * Attempting a GFD for at least 12 months prior to the screening visit. \- The participants should be instructed not to alter dietary habits including a GFD during the study period. * Valid results from central testing of blood documenting a positive result for the HLA DQ2.5 genotype (HLA-DQA1\*05 and HLA-DQB1\*02) (homozygous or heterozygous). * Experienced at least 2 gluten-related symptom events (i.e., 2 different gluten-related symptoms which are diarrhea, abdominal pain, bloating, nausea, tiredness or 1 gluten-related symptom occurred twice) within a month before the screening. * Willingness to undergo 2 on-study upper gastrointestinal endoscopies with duodenal biopsies. * Presence of ongoing duodenal mucosal damage defined as Vh:Cd of 2.5 or less Exclusion Criteria: * Participants with documented history (i.e., included in the participant's medical records) of medically diagnosed Refractory Celiac Disease (RCD) or suspected RCD by the investigator. * History of IgE-mediated reactions to wheat, barley, rye, or other ingredients in gluten-free and SIGE products used in this study (i.e., methylcellulose, and gelatin). * History of cancer, includ…