The Food and Drug Administration approved the new drug Jakafi (ruxolitinib) on Nov. 16 to treat intermediate or high-risk myelofibrosis. Myelofibrosis is a rare form of chronic leukemia, in which fibrous tissue develops in the bone marrow and slows blood cell-formation. Symptoms include an enlarged spleen, fever, night sweats, feeling full too soon and easy bruising or bleeding.Although there are other treatment methods, such as transfusion, transplantation, chemotherapy and surgery, Jakafi is the first drug specifically approved to treat the disorder, as well as the first approval for the JAK inhibitor drug class. Jakafi inhibits the enzymes Janus-associated kinase (JAK) 1 and 2, which are involved in regulating blood. The approval is based on two phase 3 trials, which evaluated 528 patients total. In the COMFORT-I trial, about 42 percent of patients on Jakafi experienced at least a 35 percent reduction in spleen volume compared with 0.7 percent on placebo. Similar results were achieved in improvement of other symptoms. The COMFORT-II trial also showed greater reduction in 35 percent of spleen volume after 4 months--28.5 percent for Jakafi versus 0 percent for the best available therapy. Results showing that Jakafi prolongs survival are expected to be presented at the American Society of Hematology annual meeting in December.Serious side effects include low platelet levels (thrombocytopenia), anemia, fatigue, dizziness and headache. Jakafi will cost $7,000 for a month's supply, or $85,000 a year, and the company already has a co-payment assistance program in place.For more details, visit jakafi.com or call 855-452-5234.