Inclusion Criteria:

• Patient is informed of the investigational nature of this study and has given written, informed consent in accordance with institutional, local, and national guidelines.
• Males or females ≥ 18 years of age.
• Premenopausal females (with the exception of those who are surgically sterile) must have a negative pregnancy test at screening; those who are sexually active must practice a highly effective method of birth control for at least 4 weeks prior to study drug administration, and must be willing to continue contraception until at least 4 weeks after the last dose of study drug.
• Patient who has received at least 24 weeks of Hematide™ dosing in a previous Affymax-sponsored study.
• One Hgb value of ≥ 10.0g/dL in the 4 weeks prior to study drug administration.

Exclusion Criteria:

• Known intolerance to Hematide™ or PEGylated products.
• History of antibodies to any erythropoiesis stimulating agent (ESA) or history of pure red cell aplasia (PRCA).
• High likelihood of early withdrawal or interruption of the study (e.g., patient suffers from any clinically significant medical disease or condition that may, in the Investigator's opinion, interfere with safety, assessment, or follow-up of the patient)
• Anticipated life expectancy < 18 months
• Receipt of any ESA other than Hematide™ at any time after patient enrollment in the previous Affymax-sponsored study