Study Suggests Polycythemia Vera Treatments Not Used to Their Full Advantage

Currently available treatments for polycythemia vera (PV) may not be used to their full advantage, suggest new real-world study results published in Annals of Hematology.

Control of hematocrit (HCT) levels is paramount to the prevention of thrombotic events and other adverse outcomes in patients with PV. Regardless of risk status, clinical guidelines recommend maintaining HCT at less than 45% for all patients, researchers explained. This can be achieved though therapeutic interventions, phlebotomy and cytoreductive medications.

In the United States, the prevalence of PV is estimated at 45 to 57 cases per 100,000 persons; these patients have reduced survival compared with an age-and sex-matched population.

To better understand real-world treatment patterns, the researchers assessed insurance claims data of US patients in the Symphony Health Solutions Integrated Dataverse.

A total of 28,306 patients who initiated treatment for PV between 2011 and 2019 were included in the study. All individuals had at least 2 PV diagnosis codes, at least 1 year of treatment history, and at least 1 prescription claim and medical claim in 2018 and 2019.

The HCT subgroup (n = 4246) had at least 2 HCT test results linked in outpatient laboratory data. Patients were also characterized as high- or low-risk at treatment initiation based on age and prior thrombotic history, the authors explained.

Analyses revealed:

• Most patients in both risk groups (60%, high risk; 83%, of low risk) initiated treatment with phlebotomy monotherapy
• During a median follow-up period of 808 days, the majority (81%, low risk; 74%, high risk) maintained their original therapy during the follow-up period
• HCT control was suboptimal in both risk groups; 54% of high-risk patients initiating with phlebotomy monotherapy sometimes/always had HCT levels above 50%; among low-risk patients, 64% sometimes/always had HCT levels above 50%
• 16% of individuals experienced at least 1 thrombotic event after treatment initiation, with 20% (n = 3920) from the high-risk group and 8% (n = 629) from the low-risk group

Average age at initial treatment was 63.8 years and most patients were male. Thirty percent of patients were classified as low risk. In general, these patients were younger than those classified as high risk and had a higher proportion of males-to-females.

To the authors’ knowledge, the current study is the largest real-world analysis reporting treatment patterns and thrombotic event rates in patients with PV of all ages and risk categories.

Guidelines for treating the condition have changed over time, the researchers explained.

“As the association of higher hematocrit levels and the risk of thrombotic events has been further elucidated, guidance regarding hematocrit control has become more important,” they said.

The current study revealed a significant gap between recommended treatment and actual treatment patterns, theauthors added. In addition, data showed that despite treatment, most high-risk patients were poorly controlled.

Compared with a previous study, the percentage of high-risk patients who did not meet the guideline target of HCT below 45% is considerably higher. However, this difference could be attributed to the prospective nature of the previous study.

Furthermore, regardless of treatment received, a sizable proportion of patients in the current study had at least 1 HCT measurement over 50%.

The potential for incomplete or missing records marks a limitation, along with potential misdiagnoses of PV. Uninsured patients were also not included in this study, and those insured by Medicaid or fee-for-service Medicare are likely to be underrepresented, the researchers said.

“These descriptive findings merit more detailed exploration in other studies, but these data do indicate substantial collective reliance on an established therapy, phlebotomy, despite a low percentage of patients achieving guideline-recommended results in hematocrit control and 8% of low-risk and 20% of high-risk patients experiencing thrombotic events despite access to all available treatment options,” they concluded.

Reference

Verstovsek S, Pemmaraju N, Reaven NL, et al. Real-world treatments and thrombotic events in polycythemia vera patients in the USA. Ann Hematol. 2023;102(3):571-58. doi:10.1007/s00277-023-05089-6