Pegylated interferon can control myelodysplastic/myeloproliferative syndrome with ring sideroblasts and thrombocytosis

Background:In 2016 WHO recognized the provisional entity refractory anemia with ring sideroblasts and thrombocytosisas a distinct entity and renamed it myelodysplastic/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis (MDS/MPN-RS-T). The disease presents hallmarks of both myelodysplastic and myeloproliferative features. Although the diagnostic criteria are well defined and there are several studies of the molecular landscape of the disease, the treatment regimen of these patients remains inconsistent. Due to lack of clinical trials, treatment options are chosen either on MDS- or MPN-based regimens and individual preferences such as patients characteristics and clinical presentation. Prevention of thromboembolic events is a reasonable goal. However, the use of platelet-lowering drugs is still not well studied and treatment related anemia leading to transfusions with accelerated iron overload limits a general use of cytoreductive treatment. To avoid worsening of the anemia while efficiently reducing thrombocytosis we treated 3 patients with pegylated interferon (pIFN) and provide insight in JAK2-allele burden measurement and additional mutations obtained with next generation sequencing (NGS).