FDA Approves Novel Treatment for Chronic Bone Marrow Disease

The US Food and Drug Administration (FDA) announced today the approval of a new use for Jakafi (ruxolitinib) to treat patients afflicted with polycythemia vera, a chronic type of bone marrow disease associated with phlebitis, splenomegaly, and other potentially severe symptoms.

The first drug approved by the FDA for this condition, Jakafi’s new use is intended to treat polycythemia vera patients who have an inadequate response to or cannot tolerate hydroxyurea, another medicine often prescribed to reduce the number of red blood cells and platelets in the blood.

Jakafi works by inhibiting the enzymes Janus Associated Kinase (JAK) 1 and 2, which help regulate blood and immunological functioning. The FDA says this approval will help decrease the occurrence of splenomegaly and the need for phlebotomy, a procedure to remove excess blood from the body.

Richard Pazdur, MD, director of the Office of Hematology and Oncology Products in the FDAs Center for Drug Evaluation and Research, said, “The approval of Jakafi for polycythemia vera underscores the importance of developing drugs matched to our increasing knowledge of the mechanisms of diseases. The trial used to evaluate Jakafi confirmed clinically meaningful reductions in spleen size and the need for phlebotomies to control the disease.”

The study evaluated a total of 222 participants suffering from the disease for at least 24 weeks to measure the reduced need for phlebotomy beginning at Week 8 through 32. Patients were randomly assigned to receive Jakafi or the best available therapy.

Results showed 21% of Jakafi-treated participants experienced a reduction in the need for a phlebotomy, as well as a reduction in spleen volume, compared to 1% of participants who received best available therapy.

During the trial, the most common side effects associated with Jakafi use were anemia and thrombocytopenia. Furthermore, the most common non-blood related side effects were dizziness, constipation and shingles.

The FDA reviewed Jakafi under its priority review program because the drug “demonstrated the potential to be a significant improvement in safety or effectiveness over available therapy in the treatment of a serious condition,” according to an FDA news release. Jakafi also received an orphan product designation because it is intended to treat a rare disease.

Jakafi was previously approved in 2011 to treat intermediate or high-risk myelofibrosis, including primary myelofibrosis, post-polycythemia vera myelofibrosis, and post-essential thrombocythemia myelofibrosis.