Jakafi First Drug Approved by FDA for Bone Marrow
Disease Myelofibrosis
Increasing trend in oncology where detailed scientific understanding of mechanisms of a disease allows a drug to be
directed toward specific molecular pathways
Nov. 16, 2011 - The U.S. Food and Drug Administration today approved Jakafi (ruxolitinib) as the first drug approved to
specifically treat patients with the bone marrow disease myelofibrosis, which normally strikes people age 50 or older.
Myelofibrosis is a disease in which the bone marrow is replaced by scar tissue resulting in blood cells being made in
organs such as the liver and the spleen. This disease is marked by an enlarged spleen, anemia, decreased white blood cells and platelets, and
myelofibrosis-related symptoms.
Symptoms include fatigue, abdominal discomfort, pain under the ribs, feeling full (satiety), muscle and bone pain,
itching, and night sweats.
About Myelofibrosis
Myelofibrosis is a disorder of the bone marrow, in which the marrow is replaced by scar (fibrous) tissue.
Causes
Bone marrow is the soft, fatty tissue inside your bones. Stem cells are immature cells in the bone marrow that give rise
to all of your blood cells. Your blood is made of:
● Red blood cells (which carry oxygen to your tissues)
● White blood cells (which fight infection)
● Platelets (which help your blood clot)
Scarring of the bone marrow means the marrow is not able to make enough blood cells.
Anemia, bleeding problems, and a higher risk of infections may occur.
As a result, the liver and spleen try to make some of these blood cells. This causes these organs to swell, which is
called extramedullary hematopoiesis.
The cause of myelofibrosis is unknown. There are no known risk factors. The disorder usually develops slowly in people
over age 50.
Diseases such as
leukemia and lymphoma may also cause bone marrow scarring. This is called secondary
myelofibrosis.
Jakafi, a pill taken two times a day, inhibits enzymes called JAK 1 and 2 (Janus Associated Kinase) that are involved in
regulating blood and immunological functioning. Myelofibrosis is associated with the deregulation of JAK 1 and 2.
Jakafi represents another example of an increasing trend in oncology where a detailed scientific understanding of the
mechanisms of a disease allows a drug to be directed toward specific molecular pathways, said Richard Pazdur, M.D., director of the Office of
Hematology and Oncology Products in the FDAs Center for Drug Evaluation and Research.
The clinical trials leading to this approval focused on problems that patients with myelofibrosis commonly encounter,
including enlarged spleens and pain.
The safety and effectiveness of Jakafi was evaluated in two clinical trials with 528 patients. Patients in both trials
were resistant or refractory to available myelofibrosis therapy or ineligible for allogeneic bone marrow transplantation (procedure where a
person receives blood-forming stem cells from a genetically similar, but not necessarily identical, donor).
All patients had enlarged spleens
(splenomegaly) and were in need of treatment as a result of disease-related symptoms.
Patients in the studies were selected to receive treatment with either Jakafi, placebo (sugar pill) or the best available
therapy (hydroxyurea, a chemotherapy agent, or glucocorticoids).
A greater percentage of patients receiving Jakafi experienced more than a 35
percent reduction in spleen size when compared to patients receiving placebo or best available therapy.
Similarly, a greater proportion of
patients receiving Jakafi saw more than a 50 percent reduction in their myelofibrosis-related symptoms, including abdominal discomfort, night
sweats, itching and bone or muscle pain, than was the case in patients receiving placebo.
The most serious side effects seen in patients treated with Jakafi include low blood platelet levels (thrombocytopenia),
anemia, fatigue, diarrhea, shortness of breath (dyspnea), headache, dizziness, and nausea.
Jakafi was reviewed under the FDAs priority review program, an expedited six-month review of drugs that may offer
significant advances in treatment over available therapy or that provide a treatment when no adequate therapy exists.
The treatment is being approved ahead of the drugs Dec. 3, 2011 review goal date under the Prescription Drug User Fee
Act and has been designated as an orphan drug, which identifies the disease as affecting fewer than 200,000 people in the U.S.
Jakafi is manufactured by Incyte Corp. of Wilmington, Del.
Nov. 16, 2011 - The U.S. Food and Drug Administration today approved Jakafi (ruxolitinib) as the first drug approved to
specifically treat patients with the bone marrow disease myelofibrosis, which normally strikes people age 50 or older.