Sanofi’s Tzield (teplizumab) gained FDA clearance for stage 3 type 1 diabetes in a move that expands the CD3-directed monoclonal antibody’s disease-modifying use. The accelerated approval follows earlier back-and-forth with the agency tied to eligibility within the Commissioner’s National Priority Voucher (CNPV) program. The nod broadens Tzield into a newly defined patient population: those with recently diagnosed stage 3 T1D. The regulatory basis cited an accelerated, surrogate endpoint framework involving C-peptide decline rather than direct clinical endpoints, with confirmation pending subsequent evidence generation. The decision is likely to reshape near-term competitive dynamics in immune-modulating prevention strategies for T1D—especially against developers planning around C-peptide-based regulatory pathways.