Type 1diabetes (T1D) is caused by autoimmune destruction of the pancreatic islet ß-cells, leading to an absolute deficiency in insulin.

In health, regulatory T cells (Tregs) suppress immune responses against normal tissues, and likewise prevent autoimmune diseases. Tregs are insufficient in T1D.

The investigators previously showed that administration of low doses of IL-2 induces selective expansion and activation of Tregs in mice and humans.

The investigators hypothesize that Tregs expansion and activation with low doses of IL2 could block the ongoing autoimmune destruction of insulin producing cells in patients with recently diagnosed T1D.

Scientific justification:

Clinical and preclinical studies, together with supportive mechanistic data showing that Tregs are activated by much lower IL-2 concentration than effector T cells (Teffs), provide a strong rationale for studying efficacy of low dose IL2 to stop the autoimmune destruction of insulin-secreting beta cells in patient with recently diagnosed with T1D.

Primary objective:

1. To evaluate efficacy of low dose IL-2 for the preservation of residual pancreatic β cells function
2. To select the optimal regimen of administration of IL-2

Primary assessment criterion:

AUC (T0-T120) of serum C-peptide, determined after a mixed meal tolerance test at month 12, compared to baseline.

Secondary objectives:

1. To assess Tregs expansion after an induction period and during maintenance therapy
2. To assess safety of IL-2 during the treatment period (1 year) and 1 year after its discontinuation
3. To assess the relation between Tregs expansion and preservation of residual pancreatic β cells function
4. To assess clinical and biological responses according to (i) pubertal stage group, (i) time from diagnosis to treatment initiation, (iii) biomarkers of responses
5. To assess effects of IL-2 on disease-specific immune responses
6. To identify biomarkers for predicting/monitoring safety and efficacy of IL-2.

Secondary assessment criteria:

• Serum concentrations of C-peptide
• AUC (T0-T120) of serum C-peptide after a mixed meal tolerance test after treatment discontinuation
• Diabetic monitoring (insulin use)
• HbA1c and IDAA1c score
• Number of hypoglycaemic episodes (< 0.5 g/L on capillary sample) over 15 days before each visit.
• Number of clinically significant symptomatic episodes of hypoglycaemia between each visit.
• Change in Tregs (expressed as percentage of CD4 and absolute numbers) at day 5 compared to baseline.
• Change in trough level of Tregs (%CD4+ and absolute numbers) at month 1, month 3, month 6, month 9, month 12, compared to baseline; and then month 15 and 24 after treatment discontinuation.
• Change in Foxp3 gene methylation
• Cytokines and chemokines assays at day 5, month 1, month 3, month 6, month 9, and month 12 compared to baseline and then month 15 and month 24 after treatment discontinuation.
• Transcriptome analysis.
• Genotyping at baseline
• Treg phenotype and functionality in adults and adolescents only including pStat5 analysis

Pharmacokinetic of IL2 will be performed (in patients from regimen A only) on day 1 at T0, T60min (1h), T120min (2h), T240min (4h), T360min (6h), T600min (10h), T1440min (24h=day2) on day 4, V8 (D29±1day) and V54 (day 351±3 days) at the same time points in 27 patients of regimen A.

• Safety parameters will be evaluated by clinical examination (including height/weight and pubertal stage especially for children and adolescents), routine laboratory tests, ILT-101 auto-antibodies, ancillary investigations and adverse event.

Experimental design:

This is a multicenter European, sequential-group, randomized, double-blind trial evaluating IL-2 versus placebo

Population involved:

Male or female, aged between 6 and 35 years, with type 1 diabetes diagnosed for less than two months.

Number of subjects: 138

Inclusion period: 49 months

Duration of patient participation: 24 months (treatment period: 12 months, follow-up period: 12months)

Total duration of the study: 73 months

Statistical analysis:

The principal efficacy analysis will be drawn from the intention to treat group.

The per-protocol analysis will be used to confirm the intention to treat analysis.

For each regimen:

- MMTT: C-peptide concentrations will be summarized by the AUC from T0 to T+120 min. Before statistical analysis, log (x+1) normalizing transformation will be used, and IL-2 and placebo treated patients will be compared using a mixed model of ANCOVA including baseline value as covariate and factor pubertal stage group.

Quantitative endpoints will be analyzed using same methods as primary endpoint. Categorical endpoints will be analyzed using multivariate logistic regression models.

Subgroups analyses: Response to treatment will be analysed according to criteria such as:

• Pubertal stage, age, gender, BMI…
• Biomarkers (identified in previous studies as predictive of patients' response to treatment)

Funding source: European Commission under the Health Cooperation Programme of the Seventh Framework Programme (Grant Agreement n°305380-2).

Inclusion criteria

• Age 6-35 years old.
• Male or female both using effective methods of contraception during treatment if sexually active.
• Specifically; Females (if sexually active) with childbearing potential must use contraceptive methods that are considered as highly-effective (pearl index < 1). The following methods are acceptable: Oral , injectable, or implanted hormonal contraceptives (with the exception of oral minipills ie low-dose gestagens which are not acceptable (lynestrenol and norestisteron), Intrauterine device, Intrauterine system (for example, progestin-releasing toit),
• beta HCG negative at inclusion;
• With type-1 diabetes:
• Newly diagnosed (ADA criteria, see annexe 19.6) at most three months between insulin initiation and anticipated start of experimental treatment.
• Positive for one or more of the autoantibodies typically associated with T1D (anti-islet, -insulin, -GAD, -IA2, -ZnT8)
• With a detectable peak C-peptide concentration during a standardised MMTT at Visit MMTT (≥0.2pmol/ml);
• patients with a stable blood glucose level and seric glycaemia between 60 mg/dL and 250 mg/dL verified at MMTT visit
• Absence of clinically significant abnormal laboratory values (out of range and associated with clinical symptoms or signs) in haematology, biochemistry, thyroid, liver and kidney function;
• Normal cardiac function: no documented history of heart disease and absence of family history of sudden death, normal ECG especially QTc duration within normal value (<480ms);
• Free, informed and written consent, signed by the patient and investigator before any Study examination. If the patient is a minor by child and both parents or child and the legal representative in case only one parent is alive. (Journal officiel des communautés européennes (1.5.2001)
• NB: patient with history of thyroidism on treatment at the inclusion and with normal thyroid hormone values (TSH+T4) can be included.

Exclusion criteria

• Children under the age of 6 years old cannot be included
• Patient who, before inclusion, have been treated with other anti-diabetic medication than Insulin for more than 3 months consecutively
• Chronic adrenal insufficiency known or fasting ACTH ≥2.5 ULN normal at inclusion after control;
• Anti TPO present at inclusion and abnormal TSH and T4
• Anti-transglutaminase positive at inclusion
• Hypersensitivity to the active substance or to any of the excipients
• Any major health problem including: any major auto-immune/auto-inflammatory disease (other than type 1 diabetes) present at inclusion, any significant respiratory disease (such as moderate or severe COPD or asthma) requiring the chronic use of corticosteroids (whatever route of administration) and serious digestive malfunctions.
• Patient with existing malignancy or history of malignancy
• Major psychosocial instability with expected lack of compliance with insulin treatment, psychiatric pathology of patient or parents, or major problems of family dynamics;
• Signs of active infection;
• Any patient with obesity defined as BMI ≥ 35
• Existence of a serious malfunction of a vital organ;
• History of organ allograft;
• Use of treatments not allowed in the Study (see Section 8.4.2);
• Vaccination with alive attenuated virus within 4 weeks of the first injection of the induction period and during the whole maintenance period
• Pregnant female (confirmed by laboratory testing) or lactating
• Participation in another clinical trial in the previous 3 months;
• Lack of affiliation to a social security scheme (as a beneficiary or assignee).