Table 3.

Suggested strategies in the management of chronic myeloproliferative neoplasms under COVID-19 pandemic.

Disease	Diagnostic Procedures	Initial Therapy	Intolerant/Resistant Patients	Confirmed COVID-19
Polycythemia Vera	All patients should receive a 2016WHO-defined diagnosis. A delay of BM biopsy may be considered if clinical/laboratory parameters are diagnostic for PV	Anti COVID-19 vaccination is indicated Patients do not need be tested for COVID-19 prior to initiation of therapy. Antiplatelet agents according to standard indications. If newly diagnosed indication for oral anticoagulation, DOAC instead of VKA may be appropriate. In patients treated with phlebotomy only, the hematocrit threshold should be kept <45%Cytoreduction should be started in all patients at high thrombotic risk. The cytoreductive agent should be chosen on a case-by-case evaluation	There is no contraindication of switching to a second line cytoreductive agent in case of intolerance or resistance. The start of ruxolitinib should not be delayed	For non-severe COVID-19 infection, interruption of cytoreductive agents or ruxolitinib is not recommended. For severe COVID-19 infection, dose reduction or interruption of cytoreductive agents should be based on complete blood count evaluation. The interruption of ruxolitinib during COVID-19 should be discouraged, but discussed case by case Caution should be taken with the drug-drug interactions between treatment of COVID-19 and ruxolitinib. Switch to LMWH may be suggested in patients on anticoagulation. The use of LMWH is recommended in all hospitalized cases, after evaluation of the hemorrhagic risk Aspirin should not be discontinued in the patients with a history of arterial thrombosis
Essential Thrombocythemia	All patients should receive a 2016WHO-defined diagnosis. A delay of BM biopsy after the resolution of the pandemic may be considered if a MPN driver mutation or another clonal marker is present and clinical/laboratory parameters are in line with ET	Anti COVID-19 vaccination is indicated COVID-19 swab/serology is not required but it may be suggested prior to initiation of therapy Antiplatelet agents according to standard indications If newly diagnosed indication for oral anticoagulation, DOAC instead of VKA may be appropriate. Cytoreduction should be started in all patients at high thrombotic risk. The cytoreductive agent should be chosen on a case-by-case evaluation	There is no contraindication of switching to a second line cytoreductive agent in case of intolerance or resistance	For non-severe COVID-19, interruption of cytoreductive agents is not recommended. For severe COVID-19, dose reduction or interruption of cytoreductive agents should be based on complete blood count evaluation. Switch to LMWH may be suggested in patients on anticoagulation The use of LMWH is recommended in all hospitalized cases, after evaluation of the hemorrhagic risk Aspirin should not be discontinued in the patients with a history of arterial thrombosis
Myelofibrosis	All patients should receive a 2016 WHO-defined diagnosisA delay of BM biopsy after the resolution of the pandemic should be discouraged	Anti COVID-19 vaccination is indicated Patients do not need be tested for COVID-19 prior to initiation of therapy. The initiation of ruxolitinib should not be delayed if clinically needed Hydroxyurea can be started according to clinical need Initiation of anti-anemia therapy should be started to reduce the need of RBC transfusions	There is no contraindication of switching to cytoreductive agents/fedratinib Splenectomy should not be delayed if indicated since there are no data indicating an increased risk of COVID-19 infection/complication. The delay could exacerbate abdominal symptoms and delay ASCT. Pre-splenectomy vaccine prophylaxis is recommended. The indication and timing of ASCT are based on disease status.	The interruption of ruxolitinib during COVID-19 infection should be discouraged but discussed case by case Caution should be taken with the drug-drug interactions between treatment of COVID-19 and ruxolitinib Switch to LMWH may be suggested in patients on anticoagulation. The use of LMWH is recommended in all hospitalized cases, after evaluation of the hemorrhagic risk Aspirin should not be discontinued in the patients with a history of arterial thrombosis In patients with MF and thrombocytopenia MF-related, special attention should be paid to the risk/benefit balance associated with the antithrombotic prophylaxis

ASCT: allogeneic stem cell transplantation. BM: bone marrow. DOAC: direct oral anticoagulants. LMWH: low-molecular weight heparin. RBC: red blood cells. VKA: vitamin K antagonists. In MPN patients with severe COVID-19, that present CVRF but no history of arterial thrombosis, LMWH is recommended, while aspirin can be discontinued.