Moreover, patients in the current study had both a longer median duration of disease (this study: 3.1 years, CONTINUATION-PV: 1.8 months) and a higher JAK2 V617F allele burden at baseline (this study: median 83.6%, CONTINUATION-PV: mean 42.8%) than patients in the CONTINUATION-PV study [13]. Here, JAK2 is linked to acquired polycythemia vera.