6533b837fe1ef96bd12a32da

RESEARCH PRODUCT

Efficacy of ruxolitinib retreatment in a patient with high-risk myelofibrosis using the international prognostic scoring system

subject

description

Primary myelofibrosis (PMF) is a myeloproliferative neoplasm in which clonal proliferation of hematopoietic stem cells and bone marrow fibrosis coexist.1 Patients may eventually die due to leukemic progression, which occurs in up to 20% of cases, or because of cardiovascular comorbidities or cytopenia, which causes susceptibility to infections and bleeding.2 Myelofibrosis diagnosis relies upon the evaluation of several clinical and laboratory criteria suggested by the World Health Organization (WHO) in 2016.3 The major mutations leading to myelofibrosis usually occur in the JAK2, CALR, and MPL genes. However, in almost 10% of the cases, none of the above-mentioned mutations can be detected (so-called ‘triple-negative patients’). Rarely, a number of several different mutations in genes such as LNK, CBL, TET2, ASXL1, IDH, IKZF1, EZH2, DNMT3A, TP53, SF3B1, SRSF2, and U2AF1 may occur.4,5 In the phase III studies, COMFORT-I and COMFORT-II, ruxolitinib, a JAK 1/2 inhibitor, has been demonstrated to reduce both splenomegaly and symptom burden in patients with international prognostic scoring system (IPSS) intermediate-2 and high-risk myelofibrosis, compared with placebo.6–8 In these trials, therapy discontinuation, for whichever reason (including noncompliance to study procedures), was as high as 55%. Furthermore, in the COMFORT-II trial, ruxolitinib discontinuation was due to adverse events in 24/146 (16.4%) patients in the ruxolitinib arm (R), 5/73 (6.8%) patients in the ‘best-available treatment’ arm, and 6/45 (13.3%) patients in the ruxolitinib after best-available treatment arm. In particular, hematologic toxicity in the ruxolitinib arm was 4.6% (1% anemia and 3.6% thrombocytopenia). Other reasons for therapy discontinuation were consent withdrawn, protocol deviation, noncompliance with either study medication or study procedures, unsatisfactory therapeutic effect, stem cell transplant, meeting protocol-defined imaging discontinuation criteria, investigator decision, important comorbidities/lung cancer), unspecified safety event, and modest spleen response. Recently, ruxolitinib has also been suggested for the treatment of patients who have polycythemia vera, which is resistant to or intolerant of hydroxyurea.9 We report our initial experience with a patient affected by PMF, retreated with ruxolitinib after a 3-month suspension of therapy due to clinical decision.