The following major changes and clarifications were made in the sections specified: 1. Addition of contact information for protocol vendors and responsible staff. 2. Clarification for selected inclusion/exclusion criteria of 6 months of GFD and IEL cut-off. 3. Addition of subject visits with a dietitian at Visits 1, 4, 6, and 8. Addition of the sample questions related to this consultation. 4. Addition of PK assessment at Visit 6. 5. Revision to Inclusion Criterion #4 to include the following clarification “and after exclusion of other potential causes of symptomatic non-response (eg, microscopic colitis, bacterial overgrowth, lactose intolerance, exocrine pancreatic insufficiency, hyperthyroidism, etc.) and intestinal histological abnormality (autoimmune enteropathy, giardiasis, immunodeficiency, collagenous sprue, Whipple’s disease, etc.).” 6. Revision to Exclusion Criterion #5 to provide additional examples of exclusionary history of immune suppression. 7. Revision of the Physician Global Assessment to include a Rating of Change assessment. The rating of change assessment was to be administered at Visits 1, 2, 3, 4, 6, 8, and 9. 8. Addition of a Patient Global Assessment and Rating of Change. The PtGA alone was to be administered at Visit 1. The PtGA and Patient Rating of Change were to be administered at Visits 2, 3, 4, 6, 8, and 9. 9. Addition of SAE telephone contact numbers. 10. Revision of SAE email contact number. 11. Addition of sample Investigational Product labels. 12. Addition of IHC assessments (exploratory endpoint). 13. Clarification that AEs and SAEs occurring in possible subjects traveling to study sites from countries other than study countries were to be assessed and managed in the same fashion as those appearing in subjects from study countries.

The following changes and clarifications were made in the sections specified: 1. Addition of Investigational New Drug Application (IND) number. 2. Update of contact information for protocol vendors and responsible staff. 3. Minor corrections to Schedule of Study Procedures: a. Addition of superscript to PK sample collection at Visit 6 (Week 8) to indicate that the sample for PK analysis at this visit should be collected before dosing starts. b. Clarification that the Visit 8 endoscopy and biopsy could be collected 7 days before or after Visit 8. 4. Addition of rules to stagger the randomization and initial dosing of the first ten subjects. 5. Correct provision of iVYLISA GIP test kit and instructions for home collection from Visit 1 to Visit 2. 6. Removal of mandatory hood use for preparation of clinical supplies, as long as preparation was performed using aseptic techniques, under sterile conditions. 7. Corrections to the list of Laboratory Parameters to match Schedule of Events: a. Clarification that “mRNA/DNA” at Screening and Visit 8 (Week 12) means “Biopsy mRNA” and “Biopsy DNA for TcR clonality.” b. Addition of “PK” at Visit 7 (Week 10). c. Addition of “Biopsy flow-cytometry” at Visit 8 (Week 12/Day 84) or Early Termination Visit.

The following changes and clarifications were made in the sections specified: 1. To reduce burden on patients: a. The rules for collection of stool samples were revised to allow a more flexible window of ±3 days and to allow any place of collection, not only the patient’s home. b. The time of collection of the blood cell pellet was changed to allow collection at any time during study. 2. It was clarified throughout the protocol that the DSMB would review unblinded data, including during the interim analysis. 3. Clarification that simultaneous concomitant therapy with topical and systemic steroids was permissible at or below the maximum doses indicated in the protocol. 4. Clarification that, after thawing, the product could be stored for up to 72 hours at 5 ± 3°C, and no longer than 12 hours at room temperature. After preparation (once injected in the IV bag), the study drug had to be used immediately and could only be kept at room temperature for a maximum of 12 hours including the 2 hours of the IV administration. These instructions were in line with the study manual and were correctly followed by the sites. 5. Clarification of the instructions to prepare the IV bag by withdrawing the volume of the thawed investigational product needed for the weight of the patient (8 mg per kg, calculating the volume needed given the concentration of investigational product of 100 mg/ml) and injecting this volume directly into a 100 mL 5% dextrose IV bag using the injection port at the base of the bag. These instructions were in line with the study manual and have been correctly followed by the sites. 6. Clarification of the patient populations for analysis and the statistical analysis method for the Marsh score. The definitions and method were consistent with the SAP and were used at completion of the study.