Philadelphia-negative myeloproliferative neoplasms at the 2012 ASH meeting: a personal summary
This short and personal overview summarizes new data in the field of myeloproliferative neoplasms from the 2012 American Society of Hematology meeting. In Polycythemia vera (PV) an hematocrit strictly kept below 45 % was shown to be associated with a lower cardiovascular event rate. Pegylated interferon-alpha-2b showed high rates of stable hematological responses in PV. Two small studies investigated Imetelstat and Vorinostat in essential Thrombocythemia. Imetelstat is a telomerase inhibitor and demonstrated high hematological response rates with an acceptable tolerability. Vorinostat, an histone-deacetylase inhibitor, showed moderate response rates but a poor safety profile in the two investigated entities, i.e., essential thrombocythemia (ET) and PV patients. CYT387, a Janus-kinase-2 inhibitor which is not yet approved for Myelofibrosis treatment, demonstrated reductions in spleen size comparable to those known from Ruxolitinib-treated patients. Moreover, high rates of transfusion independence were observed and lasted at least 1 year in 50 % of patients. The most frequent adverse event was thrombocytopenia constituting 22 and 24 % of grade 1/2 and 3/4 events, respectively. Another JAK-inhibitor, SAR302503, investigated in a phase II trial had shown similar reductions in spleen size and a considerable decrease in symptom burden. The most frequent grade 3/4 adverse events in patients treated with SAR302503 were anemia and thrombocytopenia. The updated data from the COMFORT-I and COMFORT-II trials showed that the survival benefit, the spleen size reductions and the increase in quality of life in Ruxolitinib treated Myelofibrosis patients were maintained during the further observation to weeks 84 and 96.