Open Label Extension Study for the Long-term Efficacy and Safety of FG-4592 in Dialysis and Non-dialysis Chronic Kidney Disease Patients

This is an open-label, long-term maintenance study of FG-4592 anemia therapy in dialysis and
non-dialysis Chronic Kidney Disease patients who have completed the Treatment Period of an
FG-4592 FibroGen-sponsored anemia Study. Subjects assigned to FG-4592 in the previous study
will continue to receive the same FG-4592 dose and dosing frequency, unless a dose
adjustment is required. An optional treatment group may allow subjects assigned to placebo
in the previous study to start active FG-4592 study treatment.

Inclusion Criteria:

1. Minimum age 18 years

2. Completed the Treatment Period of an ongoing FG-4592 FibroGen-sponsored anemia study
in the U.S.

Exclusion Criteria

1. Subjects assigned to epoetin alfa in a previous ongoing FG-4592 anemia study

2. Pregnant or breastfeeding females

3. Females of childbearing potential, unless using contraception as detailed in the
protocol; male subjects with sexual partners of childbearing potential who are not on
birth control unless the male subject agrees to use contraception

4. Subjects who received FG-4592 in a previous study that did not demonstrate adequate
hemoglobin response per the investigator's clinical judgment

5. Any medical condition that in the opinion of the investigator may pose a safety risk
to a subject in this study, or which may interfere with study participation