FLT3 and myeloproliferative disorder: While, in the analyzed studies, usage of sorafenib in combination therapies for the treatment of R/R myeloproliferative disorders yielded encouraging results based on response rates, parameters of patient overall survival and progression-free survival are still generally poor and may relate to inhibitor’s inability to induce deep molecular response and reduction of FLT3-ITD allelic burden in all treated patients [80,87].