Diagnosis and Treatment of Polycythemia Vera (PV) in Russian Federation: Single Center Experience

Background: PV is a chronic myeloproliferative neoplasm (MPN) characterized by predominant proliferation of erythroid precursors, an elevated red blood cell mass, high risk of vascular and thrombotic complications, reduced quality of life due to a substantial symptom burden (pruritus, fatigue, constitutional symptoms, microvascular disturbances, and bleeding). Conventional therapeutic options aim at reducing vascular and thrombotic risk, with low-dose aspirin and phlebotomy as first-line recommendations for patients at low risk of thrombotic events and cytoreductive therapy (hydroxyurea or interferon alpha) recommended for high-risk patients. Long-term effective and well-tolerated treatments are still lacking. Few data are available concerning patients with this condition at Russian Federation.

The aim of this study was to describe clinical and demographic characteristics of PV patients at diagnosis and review the current treatment landscape in PV.

Methods: From 2004 to 2014 in the outpatient department of Hematology Research Center 1687 patients with MPN were observed. The proportion of patients with PV was 28% (470) PMF - 31% (523), ET - 23% (389), unclassified MPN - 18% (305). We present the results of observation of 100 patients with PV who treated in the outpatient department. Long-term follow up of patients ranged from 6 to 262 months. Median follow-up - 14 months.

Results: The proportion of women was 67%, men - 33%. The age was from 23 to 80 years (median - 56 years). PV diagnosed on the classification of WHO 2008. Hemoglobin was from 149 to 260 g/L (median 181 g/L) in men, hemoglobin was from 136 to 247 g/L (median 177 g/L) in women. RBC was 4.4 - 10.0x10¹²/L (median 7,1x10¹²/L) in men, RBC 4.8 - 8.8 x10¹²/L (median 6,9x10¹²/L) in women. PLT 137 - 3934 hч10⁹/L (median 551x10⁹/L), WBC 4.0 - 69x10⁹/L (median 10,5x10⁹/L). Hematocrit 42 - 86% (median 53%). JAK2 V617F detected in 100%. Splenomegaly founded in 70%. All patients had headache, dizziness, 25% of patients - itching. All patients received symptomatic therapy, antiplatelet agents, preparations improving microcirculation and antihypoxants. 25% patients had thrombohemorrhagic complications in anamnesis.

Treatment: 49% - hudroxiurea, 14% - INFα-2b, 14% - combination therapy (hydroxyurea and phlebotomy or INFα-2b and phlebotomy), 23% - only phlebotomy. Response to treatment was evaluated according to the criteria of the ELN 2009. In the whole group of patients without the therapy frequency of complete remission - 48% partial remission - 41%, with no effect - 11%. Change of therapy was carried out in case of failure, intolerance or treatment of complications. When switching treatment from one method to another complete remission was not achieved.

Conclusion: Treatment of polycythemia is mainly symptomatic. The effectiveness of therapy I line (complete remission) from 14.5 to 71%. It is necessary to conduct clinical trials designed to evaluate the effectiveness and safety of new targeted therapies.