Low-dose Anti-Thymocyte Globulin Preserves C-Peptide and Reduces A1c in New Onset Type 1 Diabetes: Two Year Clinical Trial Data

A three-arm, randomized, double-masked, placebo-controlled phase 2b trial performed by the Type 1 Diabetes TrialNet Study Group previously demonstrated that low-dose anti-thymocyte globulin (ATG, 2.5mg/kg) preserved β-cell function and reduced HbA1c for one year in new-onset type 1 diabetes. Subjects (N=89) were randomized to: 1) ATG and pegylated granulocyte-colony stimulating factor (GCSF); 2) ATG alone; or 3) placebo. Herein, we report two-year AUC C-peptide and HbA1c, pre-specified secondary endpoints, and potential immunologic correlates. The two-year mean mixed-meal tolerance test (MMTT)-stimulated AUC C-peptide, analyzed by ANCOVA adjusting for baseline C-peptide, age, and sex (N=82) with significance defined as one-sided p + CD4 + T cells following low-dose ATG and ATG/GCSF. Low-dose ATG partially preserved β-cell function and reduced HbA1c two years after therapy in new-onset type 1 diabetes. Future studies should determine whether low-dose ATG might prevent or delay the onset of type 1 diabetes.