A Phase I/II Open-label, Single-arm, Multicenter Clinical Study to Evaluate the Safety and Efficacy of FKC289 in Subjects With Relapsed/Refractory Membranous Nephropathy

This Phase I study is designed to evaluate the safety and efficacy of FKC289 in subjects with relapsed/refractory Primary Membranous Nephropathy.The primary objectives are to assess the safety of FKC289 and to establish the recommended Phase II dose (RP2D).And this Phase II study is designed to evaluate the efficacy of FKC289.The primary objectives are to assess proportion of subjects achieving clinical response (including complete or partial response) at 6 months.