Polycythemia vera (PV) is a rare, chronic disorder characterized by overproduction (proliferation) of red blood cells in the bone marrow. PV is typically associated with an elevated white blood cell count, an elevated platelet count, and an enlarged spleen (splenomegaly). The cause of PV is not completely understood, but it may be caused by genetic mutation. Nearly all PV patients have a mutation called “JAK2 V617F” (found in the JAk2 gene) in blood-forming cells.
PV can occur at any age, but it's more common in adults older than 60. A variety of symptoms can occur in individuals with PV including nonspecific symptoms such as headaches, fatigue, weakness, dizziness or itchy skin; a variety of gastrointestinal issues; and the risk of blood clot formation, which may prevent blood flow to vital organs.
Treatment for PV is administered in consideration of age and risk factors. The treatment focuses on providing relief from the symptoms, preventing of blood clots and slowing the progression of the disease. Without treatment, PV can be life-threatening. Over time, in some cases there's a risk of progressing to more-serious blood cancers, such as myelofibrosis or acute leukemia. Proper medical care can help ease signs, symptoms and complications of this disease.
There is currently no cure for the disease. Currently available treatments includes phlebotomy, antiplatelet therapy, managing risk factors and cytoreductive therapies such as hydroxyurea (HU) and PEG-INF α-2a. The treatment for the disease focuses on providing relief from the symptoms, preventing of blood clots and slowing the progression of the disease. Although some patients respond well to current therapies, effective and well-tolerated treatments are still lacking for both low- and high-risk patients. Thus, there still remains an unmet medical need for improved therapy and symptom management in PV.
The first-line therapy for high-risk patients is either hydroxyurea or interferon. Hydroxyurea is a chemotherapeutic agent that has be used for decades, though some studies suggest that it may increase the risk of PV transforming into acute myeloid leukemia. Interferon is a biological agent injected three to five times a week. It can be as effective as hydroxyurea, but it more often causes side effects, such as flu-type symptoms, autoimmune diseases, and depression. Pegylated interferons (ie, long-acting interferons) that are given as an injection every week or two, appear to be much better tolerated, leading to improved response rates. Some patients also have a significant decrease in the disease burden, an effect not seen with hydroxyurea. Thus, Ropeginterferon alfa-2b (P1101) may have the potential to affect the disease biology. The results of P1101 in treating PV has shown excited results and were reported in ASH meetings.