A Study to Evaluate the Safety and Efficacy of SCTC21C in Combination With Bortezomib, Cyclophosphamide, and Dexamethasone in Patients With Newly Diagnosed Systemic Light-Chain Amyloidosis (NDSLCA)

The purpose of this study is to evaluate the efficacy and safety of SCTC21C plus cyclophosphamide, bortezomib and dexamethasone (VCd) compared with VCd alone in treatment of newly diagnosed amyloid light chain (AL) amyloidosis participants.

This study comprises two phases: Part 1 is the safety run in, while Part 2 is a randomized, controlled, open-label, multicenter study. Both parts are divided into three stages: the screening period (up to 28 days before first dose/randomization), the treatment period (from Cycle 1 \[28 days\] Day 1 and continues until disease progression or unacceptable toxicity), and the follow-up period (Postintervention). Safety endpoints include treatment-emergent adverse events , treatment-related adverse events, serious adverse events, clinical laboratory tests, vital signs, physical examinations, electrocardiograms , etc. Efficacy endpoints include Overall Complete Hematologic Response (CHR)，objective response rate (ORR), Hematologic Very Good Partial Response (VGPR) or Better Rate, Overall Survival (OS).