LIN-2102

Primary objective: To evaluate the preliminary efficacy of SLN12140 after subcutaneous injection in subjects with IgA nephropathy. Secondary objectives: To evaluate changes in other efficacy endpoints after subcutaneous injection of SLN12140 in subjects with IgA nephropathy; to evaluate the safety of SLN12140 after subcutaneous injection in subjects with IgA nephropathy; to evaluate the pharmacokinetic (PK) characteristics of SLN12140 after subcutaneous injection in subjects with IgA nephropathy; to evaluate the immunogenicity characteristics of SLN12140 after subcutaneous injection in subjects with IgA nephropathy. Exploratory objectives: To evaluate the long-term efficacy, safety, and long-term safety of SLN12140 in IgA nephropathy patients after subcutaneous injection of SLN12140; to evaluate the long-term changes in PD parameters after subcutaneous injection of SLN12140 in IgA nephropathy patients; to evaluate the long-term immunogenicity of SLN12140 after subcutaneous injection of SLN12140 in IgA nephropathy patients; and, where data permits, to preliminarily establish a population pharmacokinetic (Pop-PK) model of SLN12140 to obtain population PK parameters, and to preliminarily explore covariates and exposure-response (E-R) relationships that may affect individual PK parameters.