C020 | REAL-WORLD OUTCOMES OF ROPEGINTERFERON ALFA-2B IN POLYCYTHEMIA VERA: IMPACT OF EARLY DOSE ESCALATION AND TREATMENT DURATION ON HEMATOLOGIC RESPONSE

Ropeginterferon alfa-2b (Ropeg) is a long-acting, monopegylated interferon approved for the treatment of polycythemia vera (PV). It offers a potentially disease-modifying treatment option with a convenient dosing schedule and promising hematologic and molecular responses; however, real-world data on its use, particularly regarding longitudinal response patterns, remain limited. This observational real-world study included 113 PV (median age 52.7 years; 68.1% male) patients treated with Ropeg at nine hematology centers across Italy. Baseline data, treatment history, dosing and subsequent hematologic responses at 3, 6, 9, 12, 18, and 24 months and discontinuation data were recorded. A logistic regression model was used to evaluate the association between early dose escalation, treatment duration, and median dose with the likelihood of achieving complete hematologic response (CHR), using a longitudinal dataset with repeated observations for each patient. Before Ropeg, 74.3% received hydroxyurea (including 2 patients also treated with ruxolitinib) for a median of 17 months; discontinuation was mainly due to intolerance (84.5%). Ropeg was used as first-line therapy in 29 patients. The mean treatment duration was 10.7 months (range 1–33.7); response data are reported in Figure1. Logistic regression analysis showed that early dose escalation (β=0.646, p<0.001) and longer treatment duration (β=0.310, p<0.001) were both independently and synergistically associated with increased response rates. Conversely, higher median doses were negatively associated with CHR (β=-0.006, p<0.001). A significant interaction between early escalation and treatment duration (β=0.611, p<0.001) indicated that the benefit of prolonged treatment was amplified in patients who escalated the dose early. The model demonstrated good fit (AIC=8442.4). Ropeg was discontinued in 20 patients (17.7%) after a median of 6.8 months, mainly due to adverse events (9.7%), lack of response (6.1%; including 3 with persistent itching), and patient choice (1.7%). This real-world study showed that Ropeg is effective in managing PV, with early dose escalation and longer treatment duration associated with better responses. The lack of a positive dose-response correlation may reflect treatment resistance among patients requiring higher doses. Discontinuation rates were low, supporting Ropeg's safety and tolerability. These findings offer practical guidance for optimizing Ropeg treatment in PV, though further research is needed to confirm long-term outcomes.