The U.S. Food and Drug Administration today expanded the approved use
of Imbruvica (ibrutinib) for patients with Waldenström’s
macroglobulinemia (WM), a rare form of cancer that begins in the body’s
immune system. The drug received a breakthrough therapy designation for
this use.
A type of non-Hodgkin lymphoma, WM usually gets worse
slowly over time and causes abnormal blood cells, known as B lymphocytes
(B-cells), to grow within the bone marrow, lymph nodes, liver, and
spleen. In WM, abnormal B-cells also overproduce a protein known as
immunoglobulin M or IgM (macroglobulin) that may lead to excess
bleeding, problems with vision and with the nervous system.
According
to the National Cancer Institute, approximately 70,800 Americans were
diagnosed and 18,990 died from non-Hodgkin lymphomas in 2014. Imbruvica
works by blocking the enzyme that allows the abnormal B-cells in WM to
grow and divide.
“Today’s approval highlights the importance of
development of drugs for supplemental indications,” said Richard Pazdur,
M.D., director of the Office of Hematology and Oncology Products in the
FDA’s Center for Drug Evaluation and Research. “Continued research has
discovered new uses of Imbruvica.”
The FDA initially granted
Imbruvica accelerated approval in November 2013 for use in patients with
mantle cell lymphoma who received one prior therapy. In February 2014,
the FDA granted accelerated approval to Imbruvica for use in patients
with previously treated chronic lymphocytic leukemia (CLL), and then in
July 2014, expanded its use to include treatment of CLL patients who
carry a deletion in chromosome 17.
The FDA based its approval of
Imbruvica for WM on a clinical study of 63 previously treated
participants. All study participants received a daily 420 milligram
orally administered dose of the medication until disease progression or
side effects became intolerable. Results showed 62 percent of
participants had their cancer shrink after treatment (overall response
rate). At the time of the study, the duration of response ranged from
2.8 months to approximately 18.8 months.
The most common side
effects associated with the drug are low blood platelet counts
(thrombocytopenia), a decrease in infection-fighting white blood cells
(neutropenia), diarrhea, low red blood cell counts (anemia), lack of
energy (fatigue), musculoskeletal pain, bruising, nausea, upper
respiratory tract infection, and rash. Healthcare professionals should
inform patients of the risk for bleeding (hemorrhage), infections,
abnormal heartbeat (atrial fibrillation), development of new cancers
(second primary malignancies), metabolic disturbances following
treatment (tumor lysis syndrome), and toxic effects on an embryo
(embryo-fetal toxicity) associated with the use of Imbruvica.
The
FDA granted Imbruvica for WM breakthrough therapy designation, priority
review, and orphan product designation because the company demonstrated
through preliminary clinical evidence that the drug may offer a
substantial improvement over available therapies; has potential, at the
time of the application was submitted, to be a significant improvement
in safety or effectiveness in the treatment of a serious condition; and
the drug is intended to treat a rare disease, respectively.
The
product’s new use is being approved more than two months ahead of its
prescription drug user fee goal date of April 17, 2015, the date the FDA
was scheduled to complete review of the drug application.
Imbruvica is co-marketed by Pharmacyclics, based in Sunnyvale, California, and Janssen Biotech, based in Horsham, Pennsylvania.
The
FDA, an agency within the U.S. Department of Health and Human Services,
protects the public health by assuring the safety, effectiveness, and
security of human and veterinary drugs, vaccines and other biological
products for human use, and medical devices. The agency also is
responsible for the safety and security of our nation's food supply,
cosmetics, dietary supplements, products that give off electronic
radiation, and for regulating tobacco products.