How I treat polycythemia vera

Patterns of hydroxyurea use and clinical outcomes among patients with polycythemia vera in real-world clinical practice: a chart review

BACKGROUND

Hydroxyurea (HU) is among the most commonly used cytoreductive treatments for polycythemia vera (PV), but previous research and clinical experience suggest that not all patients respond optimally, consistently, or durably to HU treatment. This study investigated patterns of HU use and impact on disease control among patients with PV in real-world clinical practice in the United States.

METHODS

Oncologists and hematologists recruited between April and July 2014 reported data from patient charts. Treatment history and disease symptom comparisons between HU subgroups were performed using Chi square tests or one-way analyses of variance for categorical and continuous variables. Other analyses were performed using descriptive statistics.

RESULTS

Overall, 329 physicians participated and provided data on 1309 patients with PV (62.3 % male; mean age = 62.5 years, mean time since diagnosis = 5.2 years). In the 229 (17.5 %) patients who had stopped HU, the most common reasons for HU discontinuation-as assessed by the treating clinician-were inadequate response (29.3 %), intolerance (27.5 %), and disease progression (12.7 %). Among patients currently on HU, a significant proportion had elevated blood cell counts: 34.4 % had hematocrit values ≥45 %, 59.4 % had platelet levels >400 × 10(9)/L, and 58.2 % had WBC counts > 10 × 10(9)/L. Two-thirds (66.3 %) of patients had ≥1 elevated count, 40.3 % had ≥2 elevated counts, and 19.8 % had all 3 counts elevated. The most common PV-related signs and symptoms among all patients were fatigue and splenomegaly.

CONCLUSIONS

Although many patients with PV benefit from HU therapy, some continue to have suboptimal control of their disease, as evidenced by persistence of abnormally elevated blood cell counts and the continued experience of disease-related manifestations (signs and symptoms). These data further denote a significant medical need for some patients with PV currently or previously treated with HU.

MPNs as Inflammatory Diseases: The Evidence, Consequences, and Perspectives

In recent years the evidence is increasing that chronic inflammation may be an important driving force for clonal evolution and disease progression in the Philadelphia-negative myeloproliferative neoplasms (MPNs), essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF). Abnormal expression and activity of a number of proinflammatory cytokines are associated with MPNs, in particular MF, in which immune dysregulation is pronounced as evidenced by dysregulation of several immune and inflammation genes. In addition, chronic inflammation has been suggested to contribute to the development of premature atherosclerosis and may drive the development of other cancers in MPNs, both nonhematologic and hematologic. The MPN population has a substantial inflammation-mediated comorbidity burden. This review describes the evidence for considering the MPNs as inflammatory diseases, A Human Inflammation Model of Cancer Development, and the role of cytokines in disease initiation and progression. The consequences of this model are discussed, including the increased risk of second cancers and other inflammation-mediated diseases, emphasizing the urgent need for rethinking our therapeutic approach. Early intervention with interferon-alpha2, which as monotherapy has been shown to be able to induce minimal residual disease, in combination with potent anti-inflammatory agents such as JAK-inhibitors is foreseen as the most promising new treatment modality in the years to come.

Ruxolitinib for the treatment of patients with polycythemia vera

Polycythemia vera (PV) is a hematopoietic proliferative disorder associated with Janus-associated kinase/signal transducer and activator of transcription pathway dysregulation resulting in erythrocytosis and, possibly, leukocytosis and thrombocytosis. Patients diagnosed with PV experience a broad range of symptoms associated with a reduced quality of life, often develop splenomegaly, and have an increased risk of death compared with age-matched subjects without PV. Current treatment options, notably hydroxyurea, help with disease management; however, insufficient efficacy or progressive resistance occurs in some patients, highlighting the need for new treatment options. Ruxolitinib is an oral JAK1/JAK2 inhibitor that has been evaluated in Phase II and III clinical trials in patients with PV, who are intolerant of or resistant to hydroxyurea. In this setting, ruxolitinib treatment has demonstrated normalization of blood cell counts, reduction in splenomegaly and improvements in PV-related symptom burden.

The clinical and laboratory evaluation of the patient with erythrocytosis

Erythrocytosis is frequently encountered as an incidental abnormality on laboratory testing that reveals persistent elevation of the hematocrit level (>52% in men and >48% in women). In many cases, erythrocytosis is the manifestation of an underlying cardiopulmonary process, drug-induced due to androgens, or secondary to smoking, rather than a primary bone marrow disorder such as polycythemia vera. A systematic approach to the clinical and laboratory evaluation of each patient is indicated to consider diverse differential diagnosis possibilities and to identify the underlying etiology of erythrocytosis in order to formulate appropriate subspecialist referral and management plans. A thorough medical history and meticulous physical examination supplemented by a focused initial laboratory evaluation will enable the general practitioner to ascertain the etiology of erythrocytosis in the majority of cases. Patients with clinical and laboratory features suggestive of polycythemia vera and those patients without an apparent underlying condition known to cause erythrocytosis benefit from early referral to a hematologist for further specialized diagnostic evaluation and therapy considerations.

Patterns of presentation and thrombosis outcome in patients with polycythemia vera strictly defined by WHO-criteria and stratified by calendar period of diagnosis

Most studies in polycythemia vera (PV) include patients with both remote and most recent diagnostic periods and are therefore vulnerable to inaccurate interpretation of time-dependent data. We addressed the particular issue by analyzing presenting characteristics and outcome data among 1,545 patients with WHO-defined PV stratified by a diagnosis period of before or after 2005, which coincides with the first description of JAK2V617F as the molecular marker of PV. Patients diagnosed after 2005 displayed lower hemoglobin values (P < 0.0001) and older age (P = 0.007) at diagnosis; we suggest ease of diagnosis offered by a molecular marker enabled earlier diagnosis and broader application across older age groups that is further enhanced by recent trends in increased attention and health monitoring for the elderly. Post-2005 diagnosed patients were also more or less likely to receive aspirin and cytoreductive therapy, respectively, and, despite their older age distribution, displayed significantly lower risk of thrombosis in high risk disease. Regardless of the contributing factors to the latter phenomenon, our observations underscore the need to reassess current demographics and frequencies of thrombosis in clinical trial designs including thrombosis prevention in PV.