(BPT) – Polycythemia vera (PV) is a rare, chronic cancer that leads to overproduction of red blood cells, increasing the “stickiness” of blood. People with PV experience a range of symptoms, some of which may be dismissed as less serious. These include visual disturbances, shortness of breath, severe itching and poor concentration.
But the excess number of red blood cells slows blood flow, which puts people with PV at risk for additional serious health threats, including blood clots and cardiovascular events like heart attacks, strokes and mini-strokes.
“PV is diagnosed not only by detecting an elevated hematocrit but also elevated white blood cell counts and platelet counts, detection of an acquired mutation in the gene JAK2, which controls blood cell production, and characteristic changes in how bone marrow looks,” says Dr. Ronald Hoffman, Albert A. and Vera G. List Professor of Medicine and Director of the Myeloproliferative Disorders Research Program at the Icahn School of Medicine at Mount Sinai in New York, New York.
If diagnosed, people with PV can regularly undergo a standard of care procedure called phlebotomy to normalize their hematocrit, with the goal of reducing their risk of developing clots, heart attacks or strokes, he says. Phlebotomy removes blood from the body using the same procedure as donating a unit of blood.
“The established goal of phlebotomy therapy is to maintain red blood cell levels, as measured by hematocrit, below 45%,” says Hoffman. “Research shows phlebotomy is an effective treatment for PV patients, but frequently the target hematocrit level is not achieved between physician visits, leaving the patient at risk for developing clots.”
Patients with poorly controlled PV can develop scarring of their marrow known as myelofibrosis and can sometimes develop leukemia.
“PV is one of those blood cancers that you don’t hear about as much, but it is a serious disease. It’s important that patients get diagnosed and understand their treatment options,” Hoffman says.
“In addition to phlebotomy, there are a number of approved medicines that can be used to control this condition, and experimental therapeutics are also being evaluated,” he says.
An example is rusfertide. An investigational new medicine, rusfertide is still being studied by doctors and is not approved by regulatory authorities like the U.S. Food and Drug Administration (FDA) or the European Medicines Agency (EMA).
“Rusfertide was designed with the potential to control the malignant proliferation of red blood cells by limiting the supply of iron to the cells in the marrow that makes red cells,” says Dr. Arturo Molina, a physician-scientist specializing in the development of new treatments for rare and more prevalent diseases at Protagonist Therapeutics. “Rusfertide is a synthetic version of an iron regulator called hepcidin, something all people have.”
Rusfertide is currently being studied to evaluate its safety and ability to control the production of red blood cells and to keep hematocrit levels within the recommended range, potentially reducing the need for phlebotomies, its ability to impact symptoms as well as if patients experience fewer blood clots or cardiovascular complications.
“We hope that by advancing research and development of drug candidates like rusfertide, we may be able to help people with diseases like PV,” says Molina, “and to potentially add to available treatment options for PV and other rare diseases.”