Study to Evaluate the Long-term Safety of Rusfertide (PTG-300) in Subjects With Polycythemia Vera (THRIVE)

Inclusion Criteria: Subject who has completed at least 12 months of dosing with rusfertide and successfully completed the end of treatment visit of a previous Phase 2 or Phase 3 study of rusfertide. Subject understands the study procedures, is willing and able to adhere to study requirements and agrees to participate in the study by giving written informed consent. Key Exclusion Criteria: Subject who, in the opinion of the investigator, should not participate in the study. Subject who discontinue early from a previous rusfertide study for reasons other than enrolling in this study. Pregnant or lactating females. Women of childbearing potential (WOCBP) who do not agree to use medically acceptable contraception (<1% annual failure rate) during the study and for 30 days after the last dose of study drug. Men with partners of childbearing potential who do not agree to use medically acceptable contraception (<1% annual failure rate) during the study and for 90 days after the last dose of study drug. Men who do not agree to use a condom during the study and for 90 days after the last dose of study drug regardless of the partner's childbearing potential. A female subject intends to donate eggs (ova, oocytes) for the purposes of assisted reproduction during the study and for a period of 30 days after receiving the last dose of study drug. A male subject intends to donate sperm for the purpose of reproduction during the study and for a minimum of 90 days after receiving the last dose of study drug. Plan to use investigational treatment other than rusfertide during the course of the study or within 28 days after last rusfertide dose. Subject with hypersensitivity to rusfertide or to any of the excipients. In the investigator's opinion the subject has progressive disease that cannot be managed by adjusting concurrent cytoreductive therapy.