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)

A Phase 3 Randomized, Open-label, Multicenter Study to Evaluate the Safety and Efficacy of SCTC21C in Combination With Bortezomib, Cyclophosphamide, and Dexamethasone Versus Bortezomib, Cyclophosphamide, and Dexamethasone in Patients With Newly Diagnosed Systemic Light-Chain Amyloidosis

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).

Inclusion Criteria:

• Histopathological diagnosis of amyloidosis based on detection by immunohistochemistry and polarizing light microscopy of green bi-refringent material in congo red stained tissue specimens or characteristic electron microscopy appearance;
• Measurable disease of amyloid light-chain (AL) amyloidosis;
• One or more organs impacted by AL amyloidosis according to consensus guidelines
• Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) 0, 1 or 2

Exclusion Criteria:

• Prior therapy for AL amyloidosis;
• Other amyloidosis;
• Uncontrolled infection.
• Subjects with conditions that may affect safety or efficacy assessments include, but are not limited to, cardiovascular, respiratory, endocrine/metabolic, immune system, hepatic, gastrointestinal (such as gastrointestinal bleeding, perforation, ulcers, etc.), and malignant neoplasms, and are deemed clinically significant by the investigator.
• Subjects who have undergone major surgery or experienced significant trauma within 4 weeks prior to the first use of the investigational drug, or who require elective surgery during the trial period.
• Received a live or attenuated vaccine within 30 days prior to the first dose; Female subjects who are currently breastfeeding.
• Subjects with mental disorders or poor compliance, or other circumstances deemed unsuitable for participation in this study by other investigators.