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Article History

Received: 21 January 2026

Accepted: 11 May 2026

First Online: 10 September 2026

Ethics

Acknowledgements: The authors thank the participants, their families and their caregivers. The authors thank G. Comer (Provention Bio, a Sanofi company) for medical oversight of the PROTECT trial; B. DeFanti (Sanofi) for coordinating the manuscript development, facilitating author discussions, and providing a courtesy review of this manuscript; D. Carlin, Head of Biostatistics at MacroGenics, who served as a consultant and provided insights into the teplizumab clinical development programme; S. Kell, part of the medical monitoring team, who managed the PROTECT trial through the acute COVID-19 period; and R. Raymond, a prior member of the Provention Bio Biometrics team, who provided insights into the teplizumab clinical development programme. All individuals acknowledged have provided permission to be named. Medical writing support was provided by H. Ellis from Avalere Health and was funded by Sanofi.

Data availability: Qualified researchers may request access to participant-level data and related documents. Participant-level data will be anonymised, and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi’s data sharing criteria, eligible studies, and process for requesting access can be found at .

Funding: The trial was funded by Provention Bio, a Sanofi company. The funder participated in the design of the study; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication.

Authors’ relationships and activities: KCH has acted as a consultant for Provention Bio and has received a contract from Intrexon. KCH is a co‑inventor on a patent for the use of teplizumab for delay of diagnosis of stage 3 type 1 diabetes. CMD has lectured for or been involved as an advisor to Novo Nordisk, Sanofi-Genzyme, Janssen, Servier, Lilly, AstraZeneca, Provention Bio, UCB, MSD, Vielo Bio, Avotres, Worg and Novartis. CMD holds a patent jointly with Midatech plc and Provention Bio. SEG reports consultant fees from Abata Therapeutics, Eli Lilly, Genentech, Gentibio Inc, SAB Biotherapeutics, Sana Biotechnology and Sanofi, and a data and safety monitoring fee from Diamyd Medical. ZS reports speakers’ honoraria from Medtronic, Abbott and A-Import. KS has acted as a consultant for Provention Bio. AS reports speakers’ honoraria and being involved as an advisor to Sanofi. LAK is an employee of Sanofi and may hold Sanofi stock/shares. EN is an employee of Sanofi and may hold Sanofi stock/shares. MRR was an employee of Provention Bio, a Sanofi company. WT was an employee of Provention Bio, a Sanofi company. RH was an employee of Sanofi at the time of the study and may hold Sanofi stock/shares. ELR was an employee of Provention Bio, a Sanofi company, and may hold Sanofi stock/shares. LC declares that there are no relationships or activities that might bias, or be perceived to bias, their work.

Contribution statement: KCH, CMD, LC, SEG, MRR, WT and ELR were involved in the study conception and design. KCH, ZS, KS and AS performed data collection. KCH, CMD, LC, SEG, ZS, KS, AS, LAK, EN, MRR, WT, RH and ELR analysed and interpreted the data. WT developed the statistical analysis plan and performed the statistical analyses. All authors prepared the manuscript and approved the final version of the manuscript. KCH is the guarantor of this work and takes responsibility for the integrity of the work as a whole.