FrexalimAB in Preservation of Endogenous insULIN Secretion Compared to Placebo in adUlts and Adolescents on Top of inSulin Therapy (FABULINUS)

Change from baseline to W52 in mean 2h mixed meal tolerance test (MMTT) stimulated C-peptide concentration

This is a randomized, parallel group, double-blind Phase 2 study that consists of 2 parts. In
 Part A the safety of the highest dose-level of frexalimab in adults (age range 18-35 y.o.)
 will be established. In Part B, a dose-finding study (adolescents and young adults, 12-21
 y.o.) evaluating the safety and efficacy of 3 age-adjusted dose-levels of frexalimab in
 comparison with placebo in participants with newly diagnosed T1D on insulin treatment. The
 purpose of this study is to determine safety and efficacy of different dose-levels of
 frexalimab, by assessment of preservation of endogenous insulin secretion in participants
 with newly diagnosed T1D aged 12 to 21 years compared with placebo on top of standard insulin
 therapy, and to determine the dose-response relationship and minimal efficacious dose in Part
 B. Study details include: - Screening period: at least 3 weeks and up to 5 weeks (Up to 11
 days may be required to get investigational medicinal product [IMP] on site. Enrollment date
 of the participant must take into consideration this constraint.) - Double-blind treatment
 period (104 weeks): -- Main treatment period: 52 weeks -- Blinded extension: 52 weeks -
 Safety follow-up: 26 weeks (not applicable for participants entering the open-label study)
 The treatment duration will be up to 104 weeks, the total study duration will be up to 135
 weeks.