The trial is an uncontrolled, open-label, parallel group clinical trial. Approximately 10 subjects per dose group in 3 groups will be treated twice weekly for a total of 9 doses, followed by a 4-week observation period. Eligible subjects who have Hgb ≥10.5 g/dL and have stable Hgb levels will start the washout period of one to eight weeks. During the washout period, 30 subjects whose Hgb are < 10.0 will complete the baseline assessment to confirm their eligibility. Eligible subjects will be randomly assigned to one of the 3 cohorts in a 1:1:1 ratio. Subjects will be admitted on the day of the first dose and stay in the clinic overnight for pharmacokinetic (PK) sampling after the first (day 1) and the last dose (day 29). FMX-8 will be administered as 30 min i.v. infusion. After the 29-day treatment period, the trial subjects will be observed for an additional 28 days to allow safety and immunogenicity assessments.