Predictors of Response to Hydroxyurea and Switch to Ruxolitinib in HU-Resistant Polycythaemia VERA Patients: A Real-World PV-NET Study
Francesca Palandri, Elena Rossi, Giuseppe Auteri, Massimo Breccia, Simona Paglia, Giulia Benevolo, Elena Maria Elli, Francesco Cavazzini, Gianni Binotto, Alessia Tieghi, Mario Tiribelli, Florian H. Heidel, Massimiliano Bonifacio, Novella Pugliese, Giovanni Caocci, Monica Crugnola, Francesco Mendicino, Alessandra D’Addio, Simona Tomassetti, Bruno Martino, Nicola Polverelli, Sara Ceglie, Camilla Mazzoni, Rikard Mullai, A. Ripamonti, Bruno Garibaldi, Fabrizio Pane, Antonio Cuneo, Mauro Krampera, Gianpietro Semenzato, Roberto M. Lemoli, Nicola Vianelli, Giuseppe A. Palumbo, Alessandro Andriani, Michèle Cavo, Roberto Latagliata, Valerio De Stefano
Abstract
In polycythemia vera (PV), the prognostic relevance of an ELN-defined complete response (CR) to hydroxyurea (HU), the predictors of response, and patients’ triggers for switching to ruxolitinib are uncertain. In a real-world analysis, we evaluated the predictors of response, their impact on the clinical outcomes of CR to HU, and the correlations between partial or no response (PR/NR) and a patient switching to ruxolitinib. Among 563 PV patients receiving HU for ≥12 months, 166 (29.5%) achieved CR, 264 achieved PR, and 133 achieved NR. In a multivariate analysis, the absence of splenomegaly (p = 0.03), pruritus (p = 0.002), and a median HU dose of ≥1 g/day (p < 0.001) remained associated with CR. Adverse events were more frequent with a median HU dose of ≥1 g/day. Overall, 283 PR/NR patients (71.3%) continued HU, and 114 switched to ruxolitinib. In the 449 patients receiving only HU, rates of thrombosis, hemorrhages, progression, and overall survival were comparable among the CR, PR, and NR groups. Many PV patients received underdosed HU, leading to lower CR and toxicity rates. In addition, many patients continued HU despite a PR/NR; however, splenomegaly and other symptoms were the main drivers of an early switch. Better HU management, standardization of the criteria for and timing of responses to HU, and adequate intervention in poor responders should be advised.