How do you manage reactive thrombocytosis and potentially symptomatic fatigue from JAK2+ P Vera with iron deficiency?

This is a challenging scenario since if you start supplementing iron, you can increase erythropoiesis, raise the hematocrit, require more therapeutic phlebotomies, and end up chasing your own tail. For these reasons, I generally recommend against iron supplementation in PV.

Regarding the fatigue and thrombocytosis, these can both be manifestations of underlying PV. Fatigue is a classic MPN-related symptom and if there are other PV-related symptoms (aquagenic pruritis, fevers, night sweats) then this would lead me to consider giving ruxolitinib. In addition, thrombocytosis is part of the PV process (i.e. panmyelosis) but can be exacerbated in the setting of iron deficiency.

Of note, hepcidin modulating agents such as rusfertide are in develo...