[Sustained molecular response after discontinuation of ropeginterferon alfa-2b in a young patient with polycythemia vera].

Ropeginterferon alfa-2b (ropeg-IFN), a treatment that allows for prolonged dosing intervals through site-specific PEGylation, has been approved for the treatment of polycythemia vera (PV) in patients for whom existing therapies are insufficient or unsuitable. In this case report, we describe a woman in her thirties who was treated with ropeg-IFN. Blood tests showed increased levels of all three blood cell lineages, and PV was diagnosed following bone marrow examination. The patient was enrolled in a clinical study in which she received ropeg-IFN because phlebotomy could not be performed due to difficulty with securing peripheral vascular access. Complete hematologic response (CHR) was achieved 12 weeks after the start of administration, and molecular response (MR) with a JAK2 V617F allele burden of <1% was achieved after approximately 156 weeks of continuous administration of ropeg-IFN. Alopecia (grade 1) occurred as an adverse event, but resolved after ropeg-IFN dose reduction. The patient maintained CHR and MR for 2 years following treatment discontinuation. We also discuss the potential benefit of ropeg-IFN in low-risk PV patients who were not previously considered candidates for aggressive cytoreductive therapy.