Real-world hematologic response and treatment patterns among patients with polycythemia vera (PV) treated with ropeginterferon alfa-2b (ropeg)

Abstract BACKGROUND PV is a chronic myeloproliferative neoplasm characterized by elevated blood counts, especially erythrocytosis, and associated risk of thrombotic events. While cytoreductive therapy, particularly hydroxyurea (HU), has been a mainstay treatment, ropeg has emerged as a promising new treatment approach based on recent trial results, subsequent FDA approval, and inclusion as a NCCN Guideline preferred treatment. Following its pivotal trials, this is the first study that assessed treatment patterns, including first-line (1L) cytoreductive therapy, and outcomes associated with ropeg use based on electronic health records (EHR) in a real-world community setting. METHODS This retrospective observational study leveraged structured data from the iKnowMed EHR, which is used throughout The US Oncology Network and affiliated practices. The study included adult patients diagnosed with PV who were not trial participants, had at least 2 visits between November 1, 2021, and June 30, 2025, and received at least 2 prescriptions for ropeg. Patient demographic, clinical, and treatment characteristics were assessed descriptively. Best hematologic response (bHR) was defined as hematocrit (HCT) <45%, white blood cell (WBC) <10 K/uL, and platelets <400 K/uL, using the lowest observed results within 60 days of each landmark point. Best hematocrit response (HCT <45%) was also captured. Time to next treatment (TTNT) spanned from ropeg initiation to the start of the subsequent non-ropeg regimen. The average biweekly dose was calculated by dividing cumulative dose amounts by the number of syringes dispensed within 60 days of each landmark point. RESULTS Among eligible patients (n=156), 36% initiated ropeg in the 1L setting and 64% as later-line treatment (2L+). The median time from PV diagnosis to ropeg initiation was 18.8 months (interquartile range [IQR]: 2.5, 41.7), with medians of 2.0 and 26.6 months for 1L and 2L+ patients, respectively. Among 2L+ patients, prior therapies included HU (71%), ruxolitinib (25%), peginterferon alfa-2a (6%), and interferon alfa-2b (1%). Therapeutic phlebotomy was administered to 63% of patients at least once prior to ropeg initiation, and to 33% of patients following initiation. The median age at ropeg initiation was 65 years (IQR: 56, 72) with 66% 60 years or older; 54.5% were female, with the racial distribution: 80% White, 6% Black, 5% Asian, and 9% other. Baseline median (IQR) hematologic parameters were WBC 10.7 K/uL (7.3, 16.9), platelets 460 K/uL (298, 674), HCT 44.9% (40.4, 49.1), and estimated glomerular filtration rate 87.7 (63.0, 103.4). The median starting dose for ropeg was 100 mcg. An escalation in average biweekly dose was observed, with medians of 200, 234, 228, 300, and 400 mcg at 3, 6, 12, 18, and 24 months, respectively. For all patients at 3, 6, 12, 18, and 24 months, bHR rates were 30%, 43%, 44%, 53%, and 50%, and best hematocrit response (HCT <45%) was achieved by 70%, 78%, 72%, 76%, and 85% of patients. Patients starting ropeg in 1L had bHR rates of 22%, 38%, 50%, 62%, and 60% compared to 35%, 46%, 40%, 48%, and 44% for patients starting in 2L+. Best hematocrit responses were 64%, 74%, 68%, 77%, and 90% for 1L initiation and 73%, 81%, 74%, 76%, and 81% for 2L or greater. Approximately 60% of patients remained on ropeg at 27 months. Median TTNT was not reached during up to 40 months of follow-up, suggesting sustained disease stability. CONCLUSIONS This real-world study of PV patients treated with 1L and 2L+ ropeg, establishes evidence of dose escalation, as well as bHR and best hematocrit response comparable to that observed in the pivotal trials. These findings support the effectiveness of ropeg in community practice populations and provide benchmarks for future studies. Further research, including abstraction of unstructured data, is warranted to explore more details on dosing, duration of therapy, adverse effects, driver mutations, allele burden declines, and long-term outcomes.

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