This multicenter, double-masked, randomized, controlled trial evaluated whether treatment of with a target antigen (glutamic acid decarboxylase) could modulate aggressive autoimmunity effects in subjects recently diagnosed with type 1 diabetes mellitus. Subjects were randomized via a 1:1:1 ratio into one of three treatment groups: three injections of 20 μg GAD-alum, two injections of GAD-alum and one of aluminum hydroxide alone (placebo), or three injections of aluminum hydroxide. These subcutaneous injections were completed at baseline, four weeks, and twelve weeks. All subjects received intensive diabetes management with the goal of achieving excellent glycemic control. Stimulated C-peptide levels were measured at the year 1 visit via a mixed meal tolerance test (MMTT). Subjects continued follow up for a second year including the performance of a MMTT every 6 months.

The primary objective was to assess whether immunization with glutamic acid decarboxylase (GAD) formulated with aluminum hydroxide (GAD-alum) would preserve insulin production in recent-onset type 1 diabetes.

The primary outcome was the baseline-adjusted geometric mean area under the curve of serum C-peptide during the first 2 hours of a 4 hour MMTT at one year. Secondary outcomes included changes in glycated haemoglobin A(1c) (HbA(1c)) and insulin dose, and safety.

Eligible subjects were 3 to 45 years old with an insulin dependent type 1 diabetes mellitus diagnosis within the previous 100 days. Additional criteria included stimulated C-peptide levels ≥ 0.2 pmol/ml as assessed by a MMTT, presence of GAD65 antibodies, and at least one month from last immunization.

Antigen-based immunotherapy therapy with two or three doses of subcutaneous GAD-alum across 4-12 weeks does not alter the course of loss of insulin secretion during 1 year in patients with recently diagnosed type 1 diabetes.