STOP-T1D Low-Dose (ATG) (TN28)

Low Dose Antithymocyte Globulin (ATG) to Delay or Prevent Progression to Stage 3 T1D

A multi-center, placebo-controlled, double blind, 2:1 randomized control clinical trial testing low-dose ATG vs. placebo in subjects with a 2 year 50% risk of progression to stage 3 T1D. This study did not meet enrollment targets and was terminated approximately 13 months after the first participant enrolled.

Study Overview

• Status: Terminated
• Conditions: Diabetes Mellitus, Type 1
• Intervention / Treatment: Drug: Antithymocyte Globulin; Drug: Placebo (for ATG)

Detailed Description

This study has a planned enrollment period of 4 years and once the enrollment phase has concluded, an additional two years of follow-up visits will be conducted for all participants. Participants enrolled in the first year of the study can expect to complete follow-up visits for approximately four additional years if progression to stage 3 (Type 1 Diabetes Onset) does not occur. Participant follow-up visits after the treatment phase of the study includes general assessments (medical history, physical exam, medications and adverse events) and laboratory assessments to determine current health status and glucose tolerance. This study was terminated early due to lack of enrollment and infeasibility of attaining enrollment goals. Follow-up of enrolled participants continued through study termination, approximately 13 months after the first participant enrolled.

• Study Type: Interventional
• Enrollment (Actual): 2
• Phase: Phase 2

Contacts and Locations

Study Locations

• Australia
  • Queensland
    • South Brisbane, Queensland, Australia, 4101
      • Queensland Children's Hospital
  • Victoria
    • Melbourne, Victoria, Australia, 3050
      • Walter and Eliza Hall Institute of Medical Research
• United States
  • California
    • Orange, California, United States, 92868
      • Children's Hospital of Orange County
    • San Francisco, California, United States, 94143
      • University of California - San Francisco
    • Stanford, California, United States, 94305
      • Stanford University
  • Colorado
    • Aurora, Colorado, United States, 80045
      • Barbara Davis Center at University of Colorado Anschutz Medical Campus
  • Connecticut
    • New Haven, Connecticut, United States, 06511
      • Yale University School of Medicine
  • Florida
    • Gainesville, Florida, United States, 32610
      • University of Florida
    • Miami, Florida, United States, 33136
      • University of Miami
    • Tampa, Florida, United States, 33612
      • University of South Florida Diabetes Center
  • Georgia
    • Atlanta, Georgia, United States, 30322
      • Emory Children's Center
  • Indiana
    • Indianapolis, Indiana, United States, 46202
      • Indiana University - Riley Hospital for Children
  • Iowa
    • Iowa City, Iowa, United States, 52242
      • Children's Hospital of Iowa
  • Minnesota
    • Minneapolis, Minnesota, United States, 55455
      • University of Minnesota
  • Missouri
    • Kansas City, Missouri, United States, 64108
      • The Children's Mercy Hospital
  • New York
    • New York, New York, United States, 10032
      • Columbia University-Naomi Berrie Diabetes Center
  • Pennsylvania
    • Pittsburgh, Pennsylvania, United States, 15224
      • University of Pittsburgh
  • South Carolina
    • Greenville, South Carolina, United States, 29615
      • Prisma Health
  • Tennessee
    • Nashville, Tennessee, United States, 37232
      • Vanderbilt Eskind Diabetes Center
  • Texas
    • Dallas, Texas, United States, 75390
      • University of Texas Southwestern Medical Center
  • Utah
    • Salt Lake City, Utah, United States, 84132
      • University of Utah
  • Washington
    • Seattle, Washington, United States, 98101
      • Benaroya Research Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 12 years to 34 years (Child, Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Willing to provide informed consent or have a parent or legal guardian provide informed consent when the subject is <18 years of age.
2. Age greater than or equal to 6 and < 35 years
3. At least two or more diabetes-related biochemical autoantibodies (mIAA, GADA, ICA, IA-2A, ZnT8A) present on the same sample. In the absence of other antibodies, ICA and GADA positivity alone will not suffice for eligibility in this trial.
4. Weight greater than the 5th percentile for age and sex.
5. BMI < 95th and > 5th percentile for age for those under age 18 years and < 30 and > 15 for adults (≥ 18)

6. ADA Stage 2 criteria* AND at least one of the following high-risk markers (occurring at the same visit) within 7 weeks (52 days) of randomization, defined below (for defining a 2-year 50% risk for progression to Stage 3 T1D):

   a. HbA1c ≥ 5.7 and <6.5% b. Index60 ≥ 1.4 i. Index60 = 0.3695 × (log fasting C-peptide [ng/mL]) + 0.0165 × 60-min glucose (mg/dL) - 0.3644 × 60-min C-peptide (ng/mL) c. DPTRS ≥ 7.4 DPTRS = (1.57 x log BMI) - (0.06 x age) + (0.81 x glucose sum from 30 to 120 min/100) - (0.85 x C-peptide sum from 30 to 120 min/10) + (0.48 x log fasting C-peptide)

   *Dysglycemia is defined as 2-hr glucose ≥ 140 and <200 mg/dL or fasting glucose ≥ 110 and <126 or 30, 60, or 90 minute glucose ≥ 200 mg/dL from OGTT

7. CMV and/or EBV seronegative participants must be CMV and EBV PCR negative within 30 days of randomization and may not have had signs or symptoms of a CMV or EBV-compatible illness lasting longer than 7 days within 30 days of randomization.
8. CMV seropositive participants must be CMV PCR negative and all EBV seropositive participants must have EBV PCR < 2,000 IU/mL within 30 days of randomization and may not have had signs or symptoms of a CMV or EBV-compatible illness lasting longer than 7 days within 30 days of randomization.
9. Seated blood pressure less than 130/80 mmHg for participants ≥ 18 years. For participants < 18 years seated blood pressure less than 95th percentile for age, sex and height.
10. Be at least 4 weeks from last live immunization.
11. Participants are required to receive non-live influenza vaccination at least 2 weeks prior to randomization when vaccine for the current or upcoming flu season is available.
12. Participants must have a negative COVID-19 test within 7 days of the first day of treatment if otherwise eligible.
13. Willingness to comply with study directed social distancing and protection from SARS-Cov-2 infection.
14. Be willing to forgo vaccines (other than killed influenza) during the 3 months after study drug treatment period (Days 0 and 1).
15. Be up to date on all recommended vaccinations based on age of participant*
16. With the exception of stage 2 T1D, participants must be healthy, as defined by absence of any other untreated diagnoses that the protocol committee deems to be a potential confounder.
17. If a female participant with reproductive potential, willing to avoid pregnancy (abstinence or adequate contraceptive method) through the completion of the study infusions and up to 3 months after study drug administration and undergo pregnancy testing prior to each study visit.
18. Must be residing or have accommodations within 1 hour of the infusion site during the two days of study drug infusions and must be within 1 hour of a medical care facility for 1 day after completion of infusion 2.

19. Participants must live in a location with rapid access to emergency medical services.

    • Adult participants must be fully immunized. Pediatric participants who have not completed their primary vaccination schedule must receive all vaccinations allowable per the national/country-specific immunization guidelines for their current age prior to study drug delivery. Any remaining vaccinations should be given and continue per the schedule at least 3 months after study drug is administered. For COVID-19 vaccination, all participants will be strongly encouraged to be up-to-date with COVID-19 vaccine(s) as indicated by country-specific guidelines at least 2 weeks prior to randomization.

Exclusion Criteria:

1. Immunodeficiency or clinically significant chronic lymphopenia: (Leukopenia (< 3,000 leukocytes /μL), neutropenia (<1,500 neutrophils/μL), lymphopenia (<800 lymphocytes/μL), thrombocytopenia (<100,000 platelets/μL).
2. Hemoglobin less than 13.5 g/dL for adult men and less than 12 g/dL for adult females and less than 11 g/dL for participants under age 18
3. Active signs or symptoms of acute infection at the time of randomization including SARS-Cov-2.
4. Uncontrolled autoimmune thyroid disease and/or celiac disease (participants must be well controlled for the previous 6 months).
5. Evidence of prior or current tuberculosis infection as assessed interferon gamma release assay (QuantiFERON).
6. Currently pregnant or lactating or anticipate getting pregnant within the study period.
7. Require use of other immunosuppressive agents including chronic use of systemic steroids.
8. Evidence of current or past HIV or Hepatitis B or current Hepatitis C infection.
9. Any complicating medical issues or abnormal clinical laboratory results that may interfere with study conduct, or cause increased risk to include pre-existing cardiac disease, COPD, sickle cell disease, neurological disease, or blood count abnormalities.
10. A history of malignancies other than of skin.
11. Evidence of liver dysfunction with AST or ALT outside of the reference range.
12. Evidence of renal dysfunction with creatinine outside of the reference range.
13. Increased bilirubin (total and direct) outside of the normal limit (Participants with documentation of Gilbert's Disease permitted).
14. Vaccination with a live virus within the last 4 weeks.
15. Current or ongoing use of non-insulin pharmaceuticals that affect glycemic control within 7 days of screening
16. Prior treatment with Teplizumab (either in a previous clinical trial or clinically).
17. Has participated in a clinical trial for diabetes prevention previously and received active study agent within 3 months of randomization.
18. Known allergy to ATG or any product excipient
19. Prior treatment with ATG or known allergy to rabbit-derived products or to any product excipient
20. Prior adverse reactions to heparin.
21. Any condition that in the investigator's opinion may adversely affect study participation will be reviewed by the Study Chair to ensure consistency and adjudicate whether or not the subject may compromise the study results
22. Any screening/baseline laboratory result not otherwise stated out of normal reference range and/or medical history that may increase the risk of the subject's participation in this trial.
23. Previously diagnosed with Stage 3 TID according to ADA criteria (see Appendix 3 for Criteria for diagnosis of diabetes)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Antithymocyte globulin (ATG); Participants assigned to this arm will receive ATG	Drug: Antithymocyte Globulin; Antithymocyte globulin (ATG) will be intravenously administered over two days, with a total of 2 infusion periods. The first infusion is given at baseline visit (day 1), the second is given the next day at baseline visit (day 2). Body weight at baseline (Day 0- admission for the ATG/placebo infusion) will be used in calculating the doses for all infusions. The first dose (0.5mg/kg) will be infused over a minimum of 4 hours, and the second dose (2mg/kg) over a minimum of 4 hours with a maximum infusion time for each infusion of 10 hours. The second dose should be given no less than 12 and no more than 30 hours from the start of the first infusion. The final prepared product is to be labeled to protect the blind. Infusions may be administered either in a hospital or outpatient setting at the investigator's or institutions discretion.; Other Names: Thymoglobulin
Placebo Comparator: Placebo; Participants assigned to this arm will receive saline (placebo) to match ATG infusion	Drug: Placebo (for ATG); 0.9% Sodium Chloride Injection USP ("Normal" saline) is to be dispensed as the placebo for this study. The placebo is to be prepared dispensing an infusion bag of 0.9% Sodium Chloride Injection USP ("Normal" saline) with no additives (no ATG, no premedications) and label the product to protect the blind. The placebo will also be administered over a minimum of 4 hours for the first and second doses with a maximum infusion time of 10 hours. The second dose of the placebo arm should be given no less than 12 and no more than 30 hours from the start of the first infusion. Infusions may be administered either in a hospital or outpatient setting at the investigator's or institutions discretion.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Progression to Stage 3 T1D	The primary outcome is the elapsed time between random treatment assignment and the development of Stage 3 diabetes	From randomization to study termination, approximately 13 months for the first participant enrolled

Collaborators and Investigators

• Sponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
• Investigators: Principal Investigator: Michael Haller, MD, University of Florida

Publications and helpful links

Helpful Links

• TrialNet

Study record dates

Study Major Dates

• Study Start (Actual): November 1, 2023
• Primary Completion (Actual): December 17, 2024
• Study Completion (Actual): December 17, 2024

Study Registration Dates

• First Submitted: February 26, 2020
• First Submitted That Met QC Criteria: February 28, 2020
• First Posted (Actual): March 2, 2020

Study Record Updates

• Last Update Posted (Actual): May 7, 2026
• Last Update Submitted That Met QC Criteria: April 16, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: T1D; TrialNet
• Additional Relevant MeSH Terms: Endocrine System Diseases; Metabolic Diseases; Autoimmune Diseases; Immune System Diseases; Glucose Metabolism Disorders; Diabetes Mellitus; Nutritional and Metabolic Diseases; Diabetes Mellitus, Type 1; Amino Acids, Peptides, and Proteins; Proteins; Antibodies; Immunoglobulins; Immunoproteins; Blood Proteins; Serum Globulins; Globulins; Biological Products; Complex Mixtures; Immune Sera; Antilymphocyte Serum; thymoglobulin
• Other Study ID Numbers: TrialNet TN28; UC4DK117009-01 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Study was terminated early with only 2 participants enrolled.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No