A Study to Evaluate the Safety and Activity of SAR448501/DR-0201 in Patients With Autoimmune Rheumatic Diseases

This is an open-label, multi-ascending dose (MAD) phase 1 study, with dose expansion at selected doses, in adult patients with select autoimmune rheumatic diseases including systemic lupus erythematosus (SLE) or rheumatoid arthritis (RA). The purpose of the study is to identify possible optimal dose(s) by assessing the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), immunogenicity, and preliminary clinical response of SAR448501/DR-0201. The study duration per participant will be a minimum of approximately 13 months, including a screening period of up to 28 days, a treatment period of 71 days, and a follow-up period of 42 weeks. If necessary, participants will continue to have visits after End of Study (EOS) every 4 weeks until peripheral blood B cells return to at least 80% of either the lower limit of normal (LLN) or the participant's baseline value.