A Study of Rusfertide in Adults With Polycythemia Vera in China

Polycythemia vera (PV) is a long-term condition in which the bone marrow makes too many red blood cells (RBCs). Bone marrow is the soft tissue inside the large bones where blood cells are made. When there are too many RBCs, called erythrocytosis, the blood can become thicker and move less easily through blood vessels and organs. This can raise the risk of blood clots (thrombosis) in veins or arteries. Sometimes, these clots can be life-threatening and may cause a stroke or heart attack. Treatment aims to keep the percentage of RBCs in the blood (hematocrit) in a safe range. For adults with PV, this means keeping the hematocrit below 45%. This helps lower the blood thickness and the risk of thrombosis. PV can also be linked to low iron levels (iron deficiency), because the body uses iron to make more RBCs. Many people with PV are treated with blood removal (phlebotomy) to lower RBC levels in the blood. This can worsen the iron deficiency, because each blood removal also takes iron out of the body.

Rusfertide is a medicine that lowers the amount of iron available in the blood. It works like hepcidin, a natural hormone that helps control iron levels in the body. By limiting iron available for RBC production, rusfertide may help keep hematocrit below 45% and may improve symptoms. It may also reduce, or even remove, the need for phlebotomy in people.

The main aim of this study is to check how well rusfertide works to lower the number of phlebotomies needed in Chinese adults with PV. Other aims are to understand how well rusfertide works to keep hematocrit levels under control and how safe it is. The study also wants to learn how rusfertide moves through the body (pharmacokinetics) and if it causes the body's defense system to react to it (immunogenicity).

During the study, participants will receive rusfertide for up to 1 year (52 weeks) and will have to visit their study clinic several times. Blood samples will be taken several times during the study.