The duration of the study for all participants will be approximately 29 weeks:~Up to 5 weeks from initiation of screening to dose administration~Treatment on Day 1~Follow-up and observation of safety and PD for 24 weeks~Final study visit at Week 24
SAR439459 is a human anti-TGFβ monoclonal antibody. This phase 1 clinical study investigates the safety, tolerability, and activity of a single dose of SAR439459 in adult participants with OI.~Participants will receive a single IV dose of SAR439459 with safety, pharmacokinetic (PK), and pharmacodynamic (PD) assessments over 24 weeks.~There will be up to 3 dose cohorts. In addition to safety, tolerability, and PK assessments, bone mineral density (BMD) will be evaluated by dual-energy Xray absorptimetry (DXA) scan and a series of blood biomarkers will be monitored to document pharmacodynamic effects of the single dose of SAR439459.