Phlebotomy, adherence, and hematocrit control in patients with polycythemia vera in the United States: Real-world analysis.

Abstract

6568 Background: Polycythemia Vera (PV) is characterized by erythrocytosis. A key treatment goal in PV, for which phlebotomy (PHL) is recommended, is achieving and maintaining hematocrit (HCT) levels < 45% to reduce thrombotic risk. However, real-world evidence suggests PHL alone may not achieve consistent and durable HCT control. Repeated PHL may also increase treatment burden and present logistical challenges. Methods: Data were collected using the Adelphi PV Disease Specific Programme, a United States (US) cross-sectional survey (August 2025-January 2026) with retrospective chart review. Physicians reported demographics, clinical characteristics, and treatment history for the next five patients (pts) with PV that met the inclusion criteria. Interim analyses are presented descriptively. Of those receiving ≥ 1 PHL in the 12 months prior to survey, pts receiving frequent PHL were defined as ≥ 3 in 6 months or ≥ 5 in 12 months; all other pts were classified as receiving infrequent PHL. Uncontrolled HCT was defined as any HCT ≥ 45% within the prior 12 months. Results: Twenty-seven physicians provided data for 143 pts; 86 (60%) received ≥ 1 PHL in the prior 12 months; median (interquartile range (IQR)) age was 65.0 (52.0-70.0) years, 77% were male, median (IQR) time since PV diagnosis was 11.0 (4.0-33.5) months, and 62% were high risk (defined as ≥ 60 years old or history of thrombosis). Half experienced ≥ 1 barrier to receiving PHL, including care coordination challenges (22%), lack of resources (12%), travel time burden (12%) and vein access challenges (10%). In prior 12 months, physicians reported that 38% of pts were not fully adherent to PHL (attended PHL appointments as recommended <90% of the time). At the most recent consultation, 51% of pts were receiving cytoreductive therapy in addition to PHL. Frequent PHL occurred in 24% of pts and infrequent in 76% of pts. Overall, 90% (75/83) had uncontrolled HCT: 89% for frequent (17/19) vs 91% for infrequent PHL (58/64). Since their PV diagnosis, 13% (11/86) of pts had experienced a thromboembolism (TE), and of these 11 pts, 45% (5/11) had experienced a TE within the 12 months prior to survey. For all pts who had ever experienced a TE, the median (IQR) time since their most recent TE was 20.0 (2.5-32.0) months. Conclusions: Within this study, pts receiving PHL for PV commonly experienced access and logistical barriers, and incomplete PHL adherence. Nearly all pts had evidence of uncontrolled HCT in the 12 months prior to survey, including both frequent and infrequent PHL groups, and TEs were observed despite PHL treatment. These findings highlight the need for more effective and sustainable approaches to prevent consequences, such as TEs, commonly associated with uncontrolled HCT, while also reducing pt burden.