Intralymphatic Glutamic Acid Decarboxylase With Vitamin D Supplementation in Recent-Onset Type 1 Diabetes: A Double-Blind, Randomized, Placebo-Controlled Phase IIb Trial

Diabetes Care
Q1
May 2021
Citations:48
Influential Citations:5
Interventional (Human) Studies
84
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Enhanced Details

Methods
Multicenter, randomized, double-blind, placebo-controlled phase IIb trial; 109 participants aged 12–24 years with recent-onset type 1 diabetes (diabetes duration 7–193 days), elevated GAD65 autoantibodies, and fasting C-peptide >0.12 nmol/L; conducted at 18 clinics across the Czech Republic, the Netherlands, Spain, and Sweden.
Intervention
Three intralymphatic injections of 4 mg GAD-alum into inguinal lymph nodes on days 30, 60, and 90; oral vitamin D 2,000 IU daily for 120 days (starting day 1) if screening vitamin D < 100 nmol/L; two participants had vitamin D ≥ 100 nmol/L and received no vitamin D.
Results
Primary end point not met in the full analysis set: treatment effect ratio 1.091 (95% CI 0.845–1.408); P = 0.501. In prespecified HLA DR3-DQ2 subgroup (n=29 active, n=17 placebo), GAD-alum significantly preserved C-peptide AUC0–120 min at 15 months (ratio 1.557; 95% CI 1.126–2.153; P = 0.0078). Higher proportion reached partial remission (IDAA1c ≤9; 78.6% vs 40.0%; P = 0.0310) and maintained stimulated C-peptide >0.2 nmol/L and 90-min C-peptide >0.2 nmol/L at 15 months (P = 0.0310, 0.0284, 0.0086). Vitamin D supplementation had no significant effect on the primary outcome across all patients (P = 0.1186). Regimen was well tolerated; injection-site reactions were mild. Conclusion: Intralymphatic GAD-alum with vitamin D shows disease-modifying potential in recent-onset T1D for individuals with HLA DR3-DQ2, supporting a precision medicine approach; larger confirmatory trials are needed.
Limitations
Not powered for the prespecified DR3-DQ2 subgroup; small subgroup size; baseline differences between groups in HbA1c and IDAA1c within the subgroup; multiple endpoints analyzed without explicit adjustment.

Abstract

OBJECTIVE To evaluate the efficacy of aluminum-formulated intralymphatic glutamic acid decarboxylase (GAD-alum) therapy combined with vitamin D supplementation in preserving endogenous insulin secretion in all patients with type 1 diabetes (T1D) or i...