This Phase 3, multicenter, randomized, double-blind, placebo-controlled study will evaluate the efficacy, safety, and tolerability of SAB-142, a fully human anti-thymocyte globulin (h-ATG), in participants aged 5 to 40 years with Stage 3 type 1 diabetes (T1D). The study will enroll participants with recent-onset T1D (\>100 days to \<1 year from diagnosis) and established-onset T1D (≥1 year to ≤2 years from diagnosis) who retain residual beta-cell function as demonstrated by stimulated C-peptide levels \>0.2 nmol/L. Participants will be randomized in a 2:1 ratio to receive SAB-142 or placebo in addition to standard diabetes care. The primary objective is to determine whether SAB-142 preserves beta-cell function over 12 months as measured by stimulated C-peptide response during a mixed meal tolerance test (MMTT). External data from the SAB-142-201 SAFEGUARD study will be incorporated to include participants with new-onset T1D (\<100 days from diagnosis) in the primary efficacy analysis.
Participant and/or appropriate legal guardian for participants below the legal age of consent must have given written informed consent and/or assent according to local, regional and/or country specific guidance before any study-related activities are carried out and must be able to understand the full nature and purpose of the trial, including possible risks and adverse effects. Participants and legal guardians must be capable of providing informed consent and not be incapacitated.
Males and females 5-40 years old*, inclusive, at the time of randomisation.
Weight ≥16.0 kg at time of randomisation. Participants age 18-40 will have a body mass index (BMI) between 16 to 32 (inclusive).
For Cohort 2: within >100 days but <1 year (365 days) of randomisation;
Participant has known allergy, hypersensitivity or moderate to severe allergic reaction including anaphylaxis to natural or recombinant antibodies, biologic treatments, passive vaccines, pork, or any other component of the study drug formulation (including biologic medications). This includes participants with Hereditary Fructose Intolerance.
Participant has a known allergy or hypersensitivity to any of the protocol-required concomitant medications.
Participant has been an active participant in a therapeutic drug, invasive medical device, or vaccine clinical trial within 12 weeks before Screening Visit (SV)2.
Participant has received teplizumab or any investigational immunomodulatory anti-CD3 treatment within any timeframe prior to screening.