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

Contemporary Challenges in Polycythemia Vera Management From the Perspective of Patients and Physicians

Although polycythemia vera (PV) is a chronic and incurable disease, effective management can allow most patients to maintain functional lives with near-normal life expectancy. However, there remain several inter-related factors that contribute to many ongoing challenges associated with the management of PV, which this review aims to explore. First, as a disease hallmarked by constitutive activation of the JAK/STAT pathway, PV is often accompanied by inflammatory symptoms that negatively impact quality of life. Next, patients often require recurrent therapeutic phlebotomies to maintain their hematocrit below the 45% threshold that has been associated with a decreased risk of thrombotic events. The need to closely monitor hematocrit and perform conditional therapeutic phlebotomies ties patients to the healthcare system, thereby limiting their autonomy. Furthermore, many patients describe therapeutic phlebotomies as burdensome and the procedure is often poorly tolerated, further contributing to quality-of-life decline. Phlebotomy needs can be reduced by utilizing cytoreductive therapy; however, standard first-line cytoreductive options (i.e., hydroxyurea and interferon) have not been shown to significantly improve symptom burden. Collectively, current PV management, while reducing thrombotic risk, often has a negative impact on patient quality of life. As researchers continue to advance towards the goal of developing a disease-modifying therapy for patients with PV, pursuit of nearer-term opportunities to shift the current treatment paradigm towards improving symptoms without compromising quality of life is also warranted, for example, by reducing or eliminating the frequent use of phlebotomy.

Differences in Clinical Outcomes Between Hydroxyurea-Resistant and -Intolerant Polycythemia Vera Patients

BACKGROUND

Previous studies have suggested that patients with polycythemia vera (PV) who exhibit hydroxyurea-resistance (HU-R) and -intolerance (HU-I) may have distinct characteristics and clinical outcomes. However, to date, no studies have reported a comparison between these two groups or assessed prognostic factors in these patients.

METHODS

The objective of this study was to evaluate clinical outcomes and identify prognostic factors among PV patients with HU-R or HU-I. We conducted a review of PV patients who received frontline treatment with HU from nine centers and identified 90 patients with HU-R or HU-I.

RESULTS

The cumulative incidence of thrombosis after 7 years of HU-R/I was 21.4%, and the incidence of disease progression was 22.5%. Comparing the HU-R and HU-I groups, the HU-R group had a significantly higher rate of disease progression (36.7% vs. 0.56%, P = 0.009), while there was no significant difference in thrombosis incidence (19.0% vs. 22.9%, P = 0.463). Multivariate analysis revealed that HU-R was an independent prognostic factor for progression-free survival (hazard ratio, 6.27, 95% confidence interval, 1.83-21.47, P = 0.003). Additionally, higher lactate dehydrogenase levels, multiple cardiovascular risk factors, and prior thrombosis were identified as unfavorable predictors of overall survival.

CONCLUSION

These findings suggest that patients with HU-R face a higher risk of hematological transformation, but have a comparable risk of thrombosis to patients with HU intolerance. These distinctions should guide decisions on second-line treatment options and clinical trials involving these patients.

Management of classical Philadelphia chromosome-negative myeloproliferative neoplasms in Asia: consensus of the Asian Myeloid Working Group

Myeloproliferative neoplasms (MPN) are a heterogeneous group of clonal hematopoietic stem cell disorders characterized clinically by the proliferation of one or more hematopoietic lineage(s). The classical Philadelphia-chromosome (Ph)-negative MPNs include polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF). The Asian Myeloid Working Group (AMWG) comprises representatives from fifteen Asian centers experienced in the management of MPN. This consensus from the AMWG aims to review the current evidence in the risk stratification and treatment of Ph-negative MPN, to identify management gaps for future improvement, and to offer pragmatic approaches for treatment commensurate with different levels of resources, drug availabilities and reimbursement policies in its constituent regions. The management of MPN should be patient-specific and based on accurate diagnostic and prognostic tools. In patients with PV, ET and early/prefibrotic PMF, symptoms and risk stratification will guide the need for early cytoreduction. In younger patients requiring cytoreduction and in those experiencing resistance or intolerance to hydroxyurea, recombinant interferon-α preparations (pegylated interferon-α 2A or ropeginterferon-α 2b) should be considered. In myelofibrosis, continuous risk assessment and symptom burden assessment are essential in guiding treatment selection. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) in MF should always be based on accurate risk stratification for disease-risk and post-HSCT outcome. Management of classical Ph-negative MPN entails accurate diagnosis, cytogenetic and molecular evaluation, risk stratification, and treatment strategies that are outcome-oriented (curative, disease modification, improvement of quality-of-life).

Real-world patient characteristics and treatment patterns of polycythemia vera in Taiwan between 2016 and 2017: a nationwide cross-sectional study

Background

Polycythemia vera (PV) patients often experience constitutional symptoms and are at risk of thromboembolism as well as disease progression to myelofibrosis or acute myeloid leukemia. Not only is PV often overlooked but treatment options are also limited, however.

Objectives

To explore the patient characteristics and treatment pattern of PV patients in Taiwan, and compare with other countries reported in the literature.

Design

This is a nationwide cross-sectional study.

Methods

The National Health Insurance Research Database in Taiwan, which covers 99% of the population, was utilized. Patients were identified during the cross-sectional period between 2016 and 2017, and their retrospective data were retrieved from 2001 to 2017.

Results

A total of 2647 PV patients were identified between 1 January 2016 and 31 December 2017. This study described the demographic information of these patients, including number of patients by risk stratification and by sex, age at diagnosis, age at cross-sectional period, rate of bone marrow aspiration/biopsy at diagnosis, comorbidities, number of postdiagnosis thrombosis, number of disease progression, and death. The mortality rate of PV patients (4.1%) over 60 of age was higher than the general population of the same age group (2.8%). This study also compared the different treatment patterns between sexes and risk groups. Hydroxyurea was deferred to an older age, but conversely was prescribed at higher dose to younger patients. Alarmingly, a high proportion of patients did not receive phlebotomy or hydroxyurea for at least 2 years. Furthermore, discrepancies in prevalence, age at diagnosis, sex ratio, incidence of thrombosis and mortality were also found when compared with data reported in other countries.

Conclusion

The clinical landscape of PV in Taiwan between 2016 and 2017 was examined. Distinctive patterns of phlebotomy and hydroxyurea were identified. Overall, these findings highlight the importance of understanding the patient characteristics and treatment patterns of PV in different regions to better inform clinical practice and improve patient outcomes.

Real-world treatments and thrombotic events in polycythemia vera patients in the USA

Polycythemia vera (PV) is a myeloproliferative neoplasm associated with increased risk of thrombotic events (TE) and death. Therapeutic interventions, phlebotomy and cytoreductive medications, are targeted to maintain hematocrit levels < 45% to prevent adverse outcomes. This retrospective observational study examined medical and pharmacy claims of 28,306 PV patients initiating treatment for PV in a data period inclusive of 2011 to 2019. Study inclusion required ≥ 2 PV diagnosis codes in the full data period, at least 1 year of PV treatment history, and ≥ 1 prescription claim and medical claim in both 2018 and 2019. Patients having ≥ 2 hematocrit (HCT) test results in linked outpatient laboratory data (2018-2019) were designated as the HCT subgroup (N = 4246). Patients were characterized as high- or low-risk at treatment initiation based on age and prior thrombotic history. The majority of patients in both risk groups (60% of high-risk and 83% of low-risk) initiated treatment with phlebotomy monotherapy, and during a median follow-up period of 808 days, the vast majority (81% low-risk, 74% high-risk) maintained their original therapy during the follow-up period. Hematocrit control was suboptimal in both risk groups; 54% of high-risk patients initiating with phlebotomy monotherapy sometimes/always had HCT levels > 50%; among low-risk patients, 64% sometimes/always had HCT levels above 50%. Overall, 16% of individuals experienced at least 1 TE subsequent to treatment initiation, 20% (n = 3920) among high-risk and 8% (n = 629) among low-risk patients. This real-world study suggests that currently available PV treatments may not be used to full advantage.

Cytoreductive treatment in real life: a chart review analysis on 1440 patients with polycythemia vera

Purpose

Patients with polycythemia vera (PV) show an elevated incidence of thromboembolic complications and decreased survival when compared to age-matched healthy individuals. Hypercellularity as indicated by elevated hematocrit, pathophysiological changes induced by the JAK2 driver mutation and cardiovascular risk factors contribute to the increased incidence of thromboembolic events. Higher age and a history of thromboembolic events define a high-risk population of PV patients. Depending on the individual risk profile, phlebotomy or pharmacologic cytoreduction is recommended in combination with low-dose acetylsalicylic acid. Stringent cytoreduction is required for effective risk reduction. However, in recent reports, the rate of thromboembolic complications in PV patients under cytoreductive therapy appears still elevated compared to healthy individuals. This study reports on a chart review to assess for cytoreductive therapy of 1440 PV patients in real life.

Methods

Forty-two eligible hematologists/oncologists in private practice treating patients with MPN were recruited to participate in a paper–pencil-based survey conducted between January 2019 and March 2020 in Germany. Physicians were asked to report primary documented data obtained from patient charts. Descriptive analyses were conducted to assess for patient characteristics, treatment modalities, risk factors and thromboembolic complications.

Results

Data were collected from the patient charts of 1440 individuals diagnosed with PV. The patient population was older than those reported in multicenter trials with a median age of 72.2 years at the time of reporting and 63.5 years at diagnosis. Age was the main factor accounting for high-risk status with 84.7% of patients being above the age of 60 followed by thromboembolic complications reported in 21.3% of patients. The use of pharmacologic cytoreduction was highly variable between participating centers with an average of 60.7% and a range of 10.1–100%. Hydroxyurea was the most frequently used drug followed by ruxolitinib, while interferons were reported for a minority of patients. For 35.4% of patients a persistent need for phlebotomy in addition to cytoreductive treatment was reported. Although presence of high-risk criteria and insufficient disease control were reported as main triggers to initiate pharmacologic cytoreduction, 28.1% had elevated hematocrit values (> 45%) and 38.6% showed persistence of elevated leukocyte count (> 10^9/l) while on cytoreductive treatment. In contrast, physician-reported symptom burden was lower than published in clinical trials and patient-reported outcomes. The rate of patients experiencing thromboembolic complications was 32.2% at any time and 14.3% after diagnosis with most patients receiving acetylsalicylic acid and 10.8% remaining on oral anticoagulants or heparin.

Conclusions

Cytoreductive treatment of high-risk PV in real life is highly variable regarding indication for cytoreduction and definition of therapy resistance. This study highlights the need for (i) improved risk stratification for thromboembolic events, (ii) consequent indication of pharmacologic cytoreduction in high-risk PV and (iii) attention to signs of therapy resistance that can trigger an earlier and stringent switch to second line agents.

Real-World Dosing Patterns of Ruxolitinib in Patients With Polycythemia Vera Who Are Resistant to or Intolerant of Hydroxyurea

INTRODUCTION

Approximately one-quarter of patients with polycythemia vera become resistant to and/or intolerant of hydroxyurea. This analysis characterizes reasons patients were switched from hydroxyurea to ruxolitinib and describes ruxolitinib dosing patterns and outcomes in real-world clinical practice.

PATIENTS AND METHODS

This medical chart review of United States community hematology/oncology practices in the Cardinal Health Oncology Provider Extended Network included patients with polycythemia vera who were ≥18 years old, received hydroxyurea for ≥3 months, started ruxolitinib between January 1, 2015 and December 31, 2016, and had ≥2 visits during the subsequent 6 months. Clinical data were collected at predefined intervals from diagnosis to last provider visit.

RESULTS

Providers identified 249 patients for inclusion. jcauses of hydroxyurea discontinuation were resistance (78%; frequently for hematocrit ≥45% [79%]) and intolerance (28%; frequently for nausea/vomiting [50%]). Initial ruxolitinib dosing was 10 mg twice daily (recommended dose) in 131 patients (53%). Among these patients, median treatment duration was 29.2 months, 35 (27%) had dose modification (increase, n = 24; decrease, n = 11) and 4 had interruptions within 6 months. The most common reason for dose increase was continued need for phlebotomy (46%); 6 patients had dose reductions owing to reduced platelets. Hematocrit control at initiation and during the first 6 months of ruxolitinib treatment was 15% and 63%, respectively.

CONCLUSION

Most patients initiated ruxolitinib upon hydroxyurea resistance. Approximately half initiated ruxolitinib at the recommended dose, 27% of whom experienced dosing modifications within the first 6 months. After switching to ruxolitinib, most patients achieved hematocrit control and continued treatment for extended time frames.

Ruxolitinib and interferon-α2 combination therapy for patients with polycythemia vera or myelofibrosis: a phase II study

We report the final 2-year end-of-study results from the first clinical trial investigating combination treatment with ruxolitinib and low-dose pegylated interferon-α2 (PEG-IFNα2). The study included 32 patients with polycythemia vera and 18 with primary or secondary myelofibrosis; 46 patients were previously intolerant of or refractory to PEGIFNα2. The primary outcome was efficacy, based on hematologic parameters, quality of life measurements, and JAK2 V617F allele burden. We used the 2013 European LeukemiaNet and International Working Group- Myeloproliferative Neoplasms Research and Treatment response criteria, including response in symptoms, splenomegaly, peripheral blood counts, and bone marrow. Of 32 patients with polycythemia vera, ten (31%) achieved a remission which was a complete remission in three (9%) cases. Of 18 patients with myelofibrosis, eight (44%) achieved a remission; five (28%) were complete remissions. The cumulative incidence of peripheral blood count remission was 0.85 and 0.75 for patients with polycythemia vera and myelofibrosis, respectively. The Myeloproliferative Neoplasm Symptom Assessment Form total symptom score decreased from 22 [95% confidence interval (95% CI):, 16-29] at baseline to 15 (95% CI: 10-22) after 2 years. The median JAK2 V617F allele burden decreased from 47% (95% CI: 33-61%) to 12% (95% CI: 6-22%), and 41% of patients achieved a molecular response. The drop-out rate was 6% among patients with polycythemia vera and 32% among those with myelofibrosis. Of 36 patients previously intolerant of PEG-IFNα2, 31 (86%) completed the study, and 24 (67%) of these received PEG-IFNα2 throughout the study. In conclusion, combination treatment improved cell counts, reduced bone marrow cellularity and fibrosis, decreased JAK2 V617F burden, and reduced symptom burden with acceptable toxicity in several patients with polycythemia vera or myelofibrosis. #EudraCT2013-003295-12.

Patterns of Hydroxyurea Prescription and Use in Routine Clinical Management of Polycythemia Vera: A Multicenter Chart Review Study

Objective:

This study aimed to evaluate real-life data on patterns of hydroxyurea prescription/use in polycythemia vera (PV).

Materials and Methods:

This retrospective chart review study included PV patients who had received hydroxyurea therapy for at least 2 months after PV diagnosis. Data were collected from 10 representative academic medical centers.

Results:

Of 657 patients, 50.9% were in the high-risk group (age ≥60 years and/or history of thromboembolic event). The median duration of hydroxyurea therapy was 43.40 months for all patients; 70.2% of the patients had ongoing hydroxyurea therapy at last follow-up. Hydroxyurea was discontinued in 22.4% of the patients; the most common reason was death (38.5%). The predicted time until hydroxyurea discontinuation was 187.8 months (standard error: ±21.7) for all patients. This duration was shorter in females (140.3±37.7 vs. 187.8±29.7) (p=0.08). This trend was also observed in surviving patients aged ≥50 years at hydroxyurea initiation (122.2±12.4 vs. 187.8±30.7, p=0.03). Among the patients who were still on hydroxyurea therapy, 40.3% had a hematocrit concentration of ≥45% at their last follow-up visit, and the rate of patients with at least one elevated blood cell count was 67.8%.

Conclusion:

Hydroxyurea prescription patterns and treatment aims are frequently not in accordance with the guideline recommendations. Its discontinuation rate is higher in females.

Real-world, retrospective study evaluating thromboembolic events, associated risk factors, and health-care resource utilization in Japanese patients with polycythemia vera

In this retrospective, real-world study, we used medical claims data to evaluate the incidence of thromboembolic events (TEs), time to TE, associated risk factors, and health-care resource utilization (HRU) in Japanese patients with polycythemia vera (PV; N = 606) from April 1, 2008, to August 31, 2015. Baseline characteristics of interest included median age, 67.0 years; previous TEs, 11.6%; cardiovascular conditions (CVCs), 45.7%; and ≥ 3 risk factors, 17.8%. Overall, 100 patients experienced TEs (118 events) at a rate of 8.15/100 person-years [TE-free survival rate, 69.3% (2008-2015)]. The annual total health-care costs [mean (per person)] were significantly impacted by the presence of TEs (yes vs. no: ¥993,000 vs ¥459,000; P < 0.001). These results confirm that the presence of CVCs increases the risk of TEs in Japanese patients with PV; occurrence of TEs was associated with a higher HRU in these patients.

Treatment strategies for polycythemia vera: Observations in a Dutch "real-world" cohort study

OBJECTIVES

Assessment of "real-world" treatment strategies and outcome in Dutch polycythemia vera (PV) patients.

METHODS

Retrospective chart review in 150 patients with PV (WHO 2008 diagnostic criteria) from 10 major non-academic hospitals in the Netherlands.

RESULTS

Patients (median age 64 years, 49% male) frequently had cardiovascular risk factors (56%) and prior vascular events (31%). About 70% of patients were high-risk, based on ELN criteria. However, the majority of patients were treated with phlebotomies alone (55%). Cytoreduction with hydroxyurea (HU) was received by 44% as part of their initial therapy, with or without phlebotomies. The time to achieve the 45% hematocrit target was shortest in patients treated with phlebotomies with or without HU (125 ± 99 and 197 ± 249 days, respectively) compared to patients treated with only HU (232 ± 216 days). Leukocyte and platelet levels were lower in HU-treated patients, and ELN response targets were more often reached. During the median follow-up period of 4.1 years, 14 patients (9%) suffered a thrombotic vascular event.

CONCLUSIONS

In Dutch clinical practice, there is major clinical variation in treatment strategies for PV. Phlebotomizing patients shorten the time to achieve hematocrit control, while HU better controls platelet and leukocyte levels. The thrombotic vascular event rate remains clinically significant.

Health Care Costs and Thromboembolic Events in Hydroxyurea-Treated Patients with Polycythemia Vera

BACKGROUND

Patients with polycythemia vera (PV) are at increased risk of thromboembolic events (TEs), which are key contributors to reduced overall survival compared with the age- and sex-matched general population. In addition to aspirin and phlebotomy to maintain hematocrit level < 45%, many patients receive cytoreduction with hydroxyurea (HU), which is associated with improved survival and may reduce the risk of cardiovascular events and TEs. However, 1 in 4 patients become resistant to or intolerant of HU. In the general population, prophylaxis and treatment following arterial and venous thromboses are associated with increased health care resource utilization and costs.

OBJECTIVE

To describe the health care resource utilization and costs associated with TEs in patients with PV treated with HU in the United States.

METHODS

This retrospective cross-sectional analysis of the Truven Health Analytics MarketScan Research Databases included adult patients with a PV diagnosis who were newly treated with HU and continuously enrolled in medical and pharmacy benefit plans for ≥ 12 months pre- and post-index. HU treatment administration, persistence, adherence, and related adverse events, as well as TEs, were reported during the 12-month follow-up period. HU treatment patterns were further analyzed in a subgroup analysis comparing patients with and without a ≥ 45-day gap in HU treatment. Health care resource utilization and costs were analyzed in a subgroup analysis comparing patients who had TEs in the 12-month follow-up period with those who did not. Tests for statistically significant differences across the comparison groups were conducted, including chi-square tests for categorical variables and t-tests for continuous variables.

RESULTS

The records of 1,322 patients with PV were included in this study. Mean age was 66.0 years; 51.3% were men; and 14.0% had a history of TEs. During the first year of HU treatment, 764 (57.8%) patients had a treatment gap of ≥ 45 days; however, treatment adherence was similar between those with and those without a gap (85.2% vs. 90.7%, respectively). TEs occurred in 216 (16.3%) patients within 12 months of HU initiation. Health care resource utilization was higher for patients with TEs versus those without, including the proportion of patients requiring inpatient services (50.9% vs. 18.4%; P < 0.001) and emergency room visits (48.1% vs. 26.3%; P < 0.001) and the mean number of inpatient admissions (1.7 vs. 1.3; P = 0.004); office visits (18.9 vs. 14.1; P < 0.001); and prescriptions (45.8 vs. 36.2; P<0.001). In addition, total mean health care costs ($45,040 vs. $16,438; P < 0.001); inpatient costs ($18,952 vs. $4,794; P < 0.001); outpatient costs ($20,844 vs. $8,046; P < 0.001); and outpatient pharmacy costs ($5,244 vs. $3,598; P = 0.002) were higher among patients with TEs than those without.

CONCLUSIONS

Patients with PV receiving treatment with HU remain at risk for TEs. The occurrence of TEs during the 12-month follow-up in this patient population was associated with higher health care resource utilization and costs.

DISCLOSURES

This study was funded by Incyte Corporation. Parasuraman and Paranagama are employees and stockholders of Incyte Corporation. Shi and Bonafede are employees of Truven Health Analytics, which was awarded a research contract to conduct this study with and on behalf of Incyte Corporation. Study concept and design were contributed by all of the authors, who also interpreted the data and wrote and revised the manuscript. Bonafede and Shi collected the data. This study was presented as an abstract at the Academy of Managed Care Pharmacy NEXUS Annual Meeting on October 26-29, 2015, in Orlando, Florida.

Disease and treatment characteristics of polycythemia vera patients in Belgium: Results from a scientific survey

OBJECTIVE

The current survey aimed to gather predefined disease parameters and treatment strategies to characterize the polycythemia vera (PV) patient population in Belgium.

METHODS

Cross-sectional data from PV patients, seen at least once between May 2014 and May 2015 at 10 sites in Belgium, were collected in aggregated form and analyzed descriptively and quantitatively.

RESULTS

Data from 343 PV patients were collected. Of these, 174 (50.7%) were male and 256 (74.6%) were ≥60 years of age. Ninety-two (26.8%) had a prior history of thrombotic events. Considerable proportions of patients had increased hematological parameters (hematocrit > 45% [31.2%], leukocytes > 10 × 10⁹ /L [33.3%], and platelet > 400 × 10⁹ /L [38.2%]). Most patients had non-palpable spleen (284, 87.7%) and no phlebotomies during the past 6 months (197, 57.4%). Low-dose aspirin was given as thrombosis prophylaxis in 249 (72.6%) patients, while 232 (67.6%) received hydroxyurea (HU) as cytoreductive treatment. Forty-one patients (12.0%) were reported as resistant and/or intolerant to HU. Seventeen patients (5.0%) received ruxolitinib in the context of clinical trials.

CONCLUSION

This survey provides better insight into the characteristics of Belgian PV patients and currently used treatment strategies. It shows that 232 (67.6%) PV patients continue to receive HU despite being potentially HU-resistant.

Polycythemia Vera Management and Challenges in the Community Health Setting

Patients with polycythemia vera (PV) experience shortened survival, increased risk of thromboembolic and hemorrhagic events, and burdensome symptoms. For all patients with PV, treatment with aspirin and hematocrit control with phlebotomy are recommended. In addition, patients with high-risk status or poor hematocrit control benefit from cytoreductive therapy with hydroxyurea, although approximately 1 in 4 patients develops resistance or intolerance. For patients who are resistant to or intolerant of hydroxyurea, studies have shown that ruxolitinib, a Janus kinase 1/2 inhibitor, provides hematocrit control, reduces spleen size, normalizes blood counts, and improves PV-related symptoms. For many patients, PV is managed in a community health setting, and it is important that community hematologists, oncologists, and internists are familiar with the contemporary management of PV to improve patient outcomes, including management for patients who present with unique health-care needs. This review provides an overview of current treatment options for patients with PV and discusses challenging circumstances encountered by community providers in the management of PV, including symptom assessment, identification of hydroxyurea resistance/intolerance, pregnancy, elective surgeries, concomitant immunosuppressants, and managing patients in areas with limited access to specialized hematologic care.