Targeted immune modulation offers a potential pathway to induce immunotolerance in Type 1 Diabetes (T1D) without the drawbacks of traditional lymphodepletion. This Phase 1 study was presented at the European Association for the Study of Diabetes (EASD) Conference 2025. It evaluated SAB-142, a fully human anti-thymocyte polyclonal antibody, in healthy volunteers. 

Participants were randomly assigned to receive either ascending intravenous doses of SAB-142 or a matching placebo. The study tested doses up to 0.5 mg/kg on Day 1 and up to 2 mg/kg on Day 2, allowing assessment of safety, pharmacokinetics, and pharmacodynamics across escalating doses.

Transient lymphopenia was observed in all participants immediately after infusion, but abnormal lymphocyte counts resolved in most by Day 3 and fully normalized by Day 4. In contrast, low-dose rabbit anti-thymocyte antibodies caused profound and long-lasting CD4+ T cell depletion in previous studies.

In vitro analyses showed that SAB-142 binds the neonatal Fc receptor 5–7 times more strongly than rATG, and has 10-fold lower antibody-dependent cellular cytotoxicity activation. These properties suggest efficient tissue transport and reduced immune cell depletion.

The study demonstrates that SAB-142 has a favorable safety profile, supporting its further development for adults, adolescents, and pediatric patients with T1D