MedicalResearch.com Interview with: Dr. Ayalew Tefferi, M.D. Department of Medicine, Mayo Clinic Rochester, Minnesota MedicalResearch: What is the background for this study? What are the main findings? Dr. Tefferi: William Vainchenker discovered and reported an activating JAK2 mutation (JAK2V617F) in myelofibrosis and related myeloproliferative neoplasms in 2005 (Nature. 2005;434:1144-1148). This seminal observation led to the recognition of activated JAK-STAT as the potential disease-driving pathway in myeloproliferative neoplasms and development of several JAK inhibitors, including fedratinib, ruxolitinib and momelotinib, for treatment of myelofibrosis. In phase 2 studies, these JAK inhibitors showed similar activity in alleviating constitutional symptoms and reducing spleen size. However, none of them were able to induce complete or partial remissions or reversal of bone marrow fibrosis or significant lowering of JAK2 mutant allele burden. A subsequent phase 3 study provided the information required for FDA approval of ruxolitinib and the current phase 3 study was meant to do the same for fedratinib. (more…)