Burden of illness and hematocrit control among patients with high- and low-risk polycythemia vera receiving current standard of care treatment in the United States Free

Introduction: Polycythemia vera (PV) is a myeloproliferative neoplasm characterized by the uncontrolled excessive production of red blood cells resulting in elevated hematocrit (HCT) and increased blood viscosity. Current standard of care (SoC) includes phlebotomy (PHL) and/or cytoreductive therapies (e.g., hydroxyurea [HU], ruxolitinib, interferons) and aims to control red blood cell production targeting HCT <45% (which is associated with lower risk of thrombotic events [TE] vs. HCT ≥45%) and managing PV symptoms. With the current SoC, there are still unmet needs in PV care. This study characterizes the treatment profiles, clinical outcomes (and costs following TE), and HCT control of patients with high- and low-risk PV treated with current SoC in the United States.

Methods: Patients with claims for PV diagnosis and treatment during 1/1/2011-12/31/2022 were identified in the MarketScan Commercial and Medicare Databases. Index date was set as the earliest PV treatment date identified. Six months of continuous enrollment prior to index (pre-index period), no evidence of disease progression (myelofibrosis, acute myeloid leukemia, or myelodysplastic syndrome) during the pre-index period, and at least 12 months of continuous enrollment after index (post-index period) were required. Patients were categorized as high-risk (age ≥60 at index and/or TE diagnosis any time prior to index using all available historical data) or low-risk (absence of both risk factors). Outcomes included: demographics at index date; treatment patterns and sub-optimal disease management during the first 12 months of follow-up post index; and clinical outcomes (TEs; disease progression to myelofibrosis, acute myeloid leukemia, or myelodysplastic syndrome; and iron deficiency anemia), and HCT control during the full post-index follow-up. Sub-optimal disease management was defined as the use of high-dose hydroxyurea (defined as ≥1000mg/day), frequent PHL (defined as ≥3 PHL in the first 6 months or ≥5 PHL in the first 12 months post-index), or TE. Because a TE diagnosis could be for chronic management of a prior TE, post-index TEs were defined as a TE diagnosis on an inpatient/ER claim or a TE diagnosis in any setting of care among patients with no TE during the 12 months pre-index. For high-risk and low-risk patients with a TE and at least 12 months of remaining follow-up post-TE, all-cause costs during the 12-month period were reported.

Results: The study included 11,311 treated PV patients (N=5,859 [51.8%] high-risk and N=5,452 [48.2%] low-risk). The mean age for high-risk patients was 68.3 years and 67.1% were male, while the mean age for low-risk patients was 48.9 years and 79.7% were male. During the first 12 months of follow-up, 2.1% of high-risk and 1.7% of low-risk patients received ruxolitinib and/or interferons. Among high-risk and low-risk patients, high-dose HU (13.1% vs. 6.5%) and frequent PHL (37.7% vs. 42.6%) were common, and among those who received high-dose HU, many also received frequent PHL (19.6% vs. 23.4%). With current SoC, a high percentage of both risk groups were identified with sub-optimal disease management (52.6% vs. 49.1%). During the full follow-up period (mean ~3.5 years), more high-risk patients had a TE (21.3% vs. 9.0%), experienced disease progression (6.1% vs. 2.6%), and had incident iron deficiency anemia (11.0% vs. 8.0%). Among PV patients with a TE and 12 months of data post-TE (N=811 high-risk and N=348 low-risk), all-cause costs during the 12-month period were $68,332 and $77,867, respectively. Among PV patients with HCT data available (N=765 high-risk and N=503 low-risk), 82.0% of high-risk and 90.3% of low-risk patients had uncontrolled HCT (some or all HCT measurements ≥45%), while more than half (50.2% of high-risk and 63.4% of low-risk) had some or all HCT measurements ≥50%.

Conclusion: Patients with both high-risk and low-risk PV have high treatment and disease burden with the current SoC. Available therapies (physician-directed PHL and cytoreductive therapies) do not consistently maintain HCT <45% and result in sub-optimal disease control regardless of risk stratification.