The study is a randomized, double-masked, placebo-controlled, Phase 1 dose-escalation clinical trial. The objective of the trial is to determine if IBC adjuvanted with MAS-1 is safe and will favor tolerogenic pathways to restore immunologic balance and reverse type 1 diabetes (T1D) autoimmunity.

The study is a four-arm (cohort), single center, randomized, double-masked, placebo-controlled, dose-escalation clinical trial. In this Phase I study, subjects (5 active MER3101 per arm plus 2 MAS-1 placebo) will be randomized to receive two intramuscular doses at days 0 and 28 of either MAS-1 placebo emulsion or MAS-1 adjuvanted IBC at 33, 109, and 327 µg IBC in 0.25 mL MAS-1 adjuvanted emulsion, followed by an additional arm to receive the optimal IBC dose selected from the first 3 arms in 0.25 mL MAS-1 emulsion. All groups will receive standard intensive diabetes treatment with insulin and dietary management.

The primary endpoint is assess the safety and tolerability of 3 doses of progressively higher IBC antigen doses of the vaccine, at 0.25 mL of MAS-1 adjuvant emulsion. In addition, to determine if the vaccine induces a shift towards protection shown by increased levels of IL-4, IL-5, IL-10 and TGF-b and regulatory changes in insulin-specific T and B cells using novel reagents to detect these unique populations of cells in treated subjects.

Inclusion Criteria:

1. Be between the ages of 18 and 45 years of age who meet the ADA standard T1DM criteria and are positive for at least 1 islet cell autoantibody.
2. Type 1-diabetes mellitus diagnosed within the previous 2 years at time of screening
3. Must have stimulated C-peptide levels ≥ 0.2 pmol/ml measured during a mixed meal tolerance test (MMTT) conducted at least 21 days from diagnosis of diabetes and within one month (37 days) of randomization
4. At least one month from last immunization
5. Must be willing to comply with intensive diabetes management
6. If participant is female with reproductive potential, she must have a negative pregnancy test and be willing to avoid pregnancy during the treatment period until 2 months after the last study drug administration.
7. Willing to forgo routine clinical immunizations during the first 100 days after initial study drug administration (COVID-19 vaccination is permitted 60 days following initial study drug administration)
8. Subjects must have HbA1c levels under 9.5 to be enrolled in the study.
9. At least 30 days from receiving a single dose COVID-19 vaccine or at least 30 days from completing a multi-dose COVID-19 vaccine series.

Exclusion Criteria:

1. Be currently pregnant or lactating, or anticipate getting pregnant during the treatment period until 2 months after the last study drug administration.
2. Ongoing use of medications known to influence glucose tolerance
3. Require use of systemic immunosuppressant(s)
4. Any significant diabetes complications such as renal disease (proteinuria or elevated Cr) and diabetic retinopathy
5. Have a history of malignancies
6. Be currently using non-insulin pharmaceuticals to affect glycemic control
7. Have any acute or chronic complicating medical issues or abnormal clinical laboratory results that interfere with study conduct or cause increased risk including neurological abnormalities.
8. Inability or unwillingness to comply with the provisions of this protocol
9. Have an active infection or positive tuberculosis test result.
10. Have serologic evidence of current or past HIV, Hep B, or Hep C infection.
11. Have a known history of hypersensitivity or allergy reactions to squalane or squalene based adjuvants or other components of the study immunogen
12. Subjects with a history or evidence of chronic kidney disease (serum creatinine> 1.5mg/dL)
13. Subjects with a history of proliferative diabetic retinopathy that has not been treated with laser therapy
14. Subjects with a history of neuropathy, foot ulcers, amputations, or kidney disease
15. Males of reproductive potential who are unwilling to use acceptable birth control during the treatment period through 2 months after the last study drug administration, unless the female partner is postmenopausal or surgically sterile.
16. Have current, confirmed COVID-19 infection