60‐year‐old female, JAK2‐positive PMF with splenomegalyHydroxycarbamideConstitutional symptoms and presence of peripheral blood blastsRuxolitinib and navitoclax via REFINE (NCT03222609)Cytopenias requiring navitoclax dose reductionsImprovement in symptoms and spleen sizeHerpes zoster managed with therapeutic dose then prophylactic antiviral therapy. The gene discussed is JAK2; the disease is herpes zoster.