PROUD-PV and CONTINUATION-PV

PROUD-PV randomised 257 patients with PV to ropeginterferon alfa-2b every two weeks or hydroxyurea; CONTINUATION-PV followed 171 of them. Non-inferiority for complete haematological response at 12 months was not formally shown, but from 24 months onward the interferon arm had more complete haematological responses with improved disease burden and a much higher rate of molecular response, with the JAK2 V617F allele burden falling steadily over years (Gisslinger and colleagues, Lancet Haematology 2020). The trials underpinned the EU approval in 2019 and the FDA approval in 2021.