A total of 3 dose groups of 4 mg/kg, 6 mg/kg and 8 mg/kg are designed in this study to explore the safety, tolerability and preliminary efficacy of the experimental drug administered for ≥4 cycles in patients with iMCD. Referring to the inclusion and exclusion criteria, the subjects will be enrolled from the low-dose group to the high-dose group in turn. After the last subject of each dose group completed the third administration and 2-week safety observation, the investigator and the sponsor will discuss the safety results of the subjects together in this dose group. If no any important adverse event occurs, they can enter the next dose group. If an important adverse event occurs in any subject, the investigator and the sponsor will discuss whether to continue the study in the next dose group. Dose escalation will be discontinued if more than one subject experiences an important adverse event.~If an important adverse event occurs, the investigator will perform related inspections based on the subject's condition, and for treatment.~After complete 4 cycles of dosing , no important adverse events are found in the subjects，or the subjects don't withdraw from the study although important adverse events and who's treatment effect is obvious. If the investigator judges that it may be beneficial to continue receiving the treatment for the subjects, the sponsor will continue to provide the subjects with the current dose of the experimental drug free of charge until the disease progresses, unacceptable toxicity occurs, or withdrawal of informed consent.
This study is a single-arm, open-label, multicenter, dose-escalation clinical study.Its primary purpose is to evaluate the safety and tolerability of recombinant humanized anti-interleukin-6 receptor monoclonal antibody ( Anti-IL-6R mAb ) injection in patients with Idiopathic Multicentric Castleman's Disease ( iMCD ) and to determine the recommended dose for follow-up studies. Its secondary purpose is to evaluate the preliminary efficacy, immunogenicity and pharmacokinetic ( PK ) index, pharmacodynamic ( PD ) characteristics of Anti-IL-6R mAb injection in patients with iMCD.