Does cytoreductive therapy in high risk PV reduce thrombotic events because of better normalization of blood counts as compared to phlebotomy, or through some other mechanism?

I suspect that several factors contribute to the decrease in thrombotic events. First, more consistent normalization of blood counts. However, probably more importantly is the reduction in inflammation. This would be supported by the lower thrombotic events in patients on ruxolitinib vs standard therapy (Vannucchi et al., PMID 25629741). Interestingly, in patients treated with ropeginterferon, there was not a significant reduction of thrombotic events when comparing ropeginterferon with HU (Gisslinger et al., PMID 32014125).