The goal of this Phase 2 study is to assess safety and efficacy of frexalimab to preserve -cell function in participants with newly diagnosed type 1 diabetes (T1D). In Part A, an exploratory part, adults (ages 18-35) will be treated with either high dose frexalimab, or placebo (inactive study drug). In Part B, adolescents and young adults (ages 12-21) will be treated with 3 dose levels of frexalimab or placebo.

Insulin therapy, commonly given as multiple daily injection therapy, is the only recommended treatment for Cystic Fibrosis Related Diabetes (CFRD). Traditional therapy for CFRD requires an intense daily effort related to diabetes care on top of the already burdensome management of Cystic Fibrosis. In this study, we will assess the safety and effectiveness of the iLet Bionic Pancreas, an automated insulin delivery system, which uses a continuous glucose monitor (CGM), an insulin pump, and a control formula that activates insulin delivery based on CGM glucose data.