Protagonist Therapeutics updated data from two ongoing Phase 2 studies evaluating rusfertide in patients with polycythemia vera (PV), demonstrating its ability to essentially eliminate the need for phlebotomies in patients. Rusfertide also showed rapid and sustained hematocrit control in patients requiring frequent phlebotomies or those having high baseline hematocrit levels (>48%). The data were presented in two oral presentations at the American Society of Hematology (ASH) 2021 Annual Meeting, in addition to the Company's three poster presentations: one describing the Phase 3 study design for rusfertide in PV; one presenting pre-clinical findings with a hepcidin analog in a mouse model of PV; and another poster on the Phase 2 clinical proof-of-concept data for rusfertide in hereditary hemochromatosis (HH). In this Phase 2 study, 63 phlebotomy-dependent PV patients were treated with rusfertide for up to 18 months. The results of the study demonstrated the essential elimination of the need for therapeutic phlebotomy (TP). Rapid, sustained, and durable control of hematocrit levels below 45% was observed without a significant increase in white blood cell numbers or PV-related thromboses. During the first 28 weeks on treatment, 84% of patients required no phlebotomies, 14% required one, and 2% required two phlebotomies. The most frequent adverse events were injection site reactions which were transient in nature. Importantly, none of the treated PV patients suffered from thrombotic events. Serious and Grade 3-4 events were limited in number, less than 10 at the time of data cut-off. Two SAEs were previously reported as possible related to study drug. Among patient reported outcomes, a third of the patients in the study also saw at least a 40% reduction in Myeloproliferative Neoplasm Symptom Assessment Form Total Symptom Scores (MPN-SAF-TSS) from baseline at week 28. 69% of patients reported improvement in Patient Global Impression of Change from baseline at week 8. In this Phase 2 study, induction therapy with twice weekly rusfertide was administered alone to patients with confirmed high hematocrit levels above 48%. In all 16 erythrocytotic PV patients, rusfertide demonstrated rapid reduction of hematocrit below 45% within weeks, without the need for TP. The drug was well tolerated. Post-induction, weekly rusfertide treatment maintained hematocrit levels without the need for TP. While this study remains ongoing, most reported drug related adverse events to date were grade 1-2, with injection site reactions being the most common adverse event.