[Development of novel therapeutic agents for myelofibrosis]

Myelofibrosis (MF) is a chronic myeloproliferative tumor with a poor prognosis that not only impairs the quality of life because of splenomegaly and debilitating systemic symptoms but also has a high acute myeloid leukemia progression rate. Ruxolitinib, a JAK inhibitor, enhances systemic symptoms in MF and prolongs survival; however, it is not effective in suppressing bone marrow fibrosis and leukemia progression, and allogeneic hematopoietic stem cell transplantation remains needed for treatment. As a result, many new drugs for MF are presently being developed. Many similar drugs have been demonstrated to enhance therapeutic effectiveness if combined with ruxolitinib, particularly BCL-2/BCL-XL inhibitors, bromodomain and extra-terminal domain inhibitors, and human double-minute homolog 2 inhibitors, to improve bone marrow fibrosis. This study provides an overview of drugs currently employed in clinical trials being performed in Japan.