Practical Guide for Managing Philadelphia-Negative Myeloproliferative Neoplasms in Patients with Organ Dysfunction.

backgroundClassical Philadelphia-negative myeloproliferative neoplasms (MPNs), including polycythemia vera, essential thrombocythemia, and myelofibrosis, frequently occur in patients with renal, hepatic, cardiovascular, or hematologic comorbidities. These vulnerabilities complicate treatment selection, dose adjustment, and toxicity monitoring. However, patients with advanced kidney disease, dialysis dependence, decompensated cirrhosis, severe cytopenias, or overlapping organ impairment are often underrepresented in prospective trials. SUMMARY: This narrative review presents a practical, organ-adapted framework for selecting MPN therapy in clinically complex patients. We define renal and hepatic impairment, compare commonly used cytoreductive and targeted therapies, including hydroxyurea, busulfan, anagrelide, ruxolitinib, fedratinib, momelotinib, pacritinib, ropeginterferon alfa-2b, and pegylated interferon alfa-2a, and discuss their use in dialysis, decompensated liver disease, cytopenic myelofibrosis, anemia-dominant myelofibrosis, and combined organ vulnerability. The proposed approach prioritizes label-based dose modification when available, cautious dose initiation when evidence is extrapolated, structured early monitoring, and multidisciplinary review for high-risk patients. KEY MESSAGES: Management of Philadelphia-negative MPNs in organ dysfunction should be individualized according to disease phenotype, treatment goal, organ reserve, hematologic tolerance, frailty, and label-specific safety restrictions. In renal impairment, hydroxyurea and ruxolitinib may remain feasible in selected patients when dose-adjusted and monitored closely, whereas dialysis and severe renal impairment require conservative initiation and multidisciplinary review because direct evidence remains limited. In myelofibrosis, JAK inhibitor choice should be phenotype-adapted; ruxolitinib remains a common standard when blood counts and organ function permit, momelotinib is attractive in anemia-dominant disease, pacritinib is particularly relevant in severe thrombocytopenia, and fedratinib is useful in selected settings but requires thiamine-focused safety management. In hepatic dysfunction or overlapping organ vulnerability, therapy should prioritize safety, reversible contributors, conservative starting strategies, explicit stopping rules, and early reassessment.