Washington, DC - The U.S. Food and Drug Administration today granted accelerated approval to Ibrance (palbociclib) to treat advanced (metastatic) breast cancer.

Breast cancer in women is the second most common type of cancer in the United States. It forms in the breast tissue and in advanced cases, spreads to surrounding normal tissue. The National Cancer Institute estimates that 232,670 American women were diagnosed with breast cancer and 40,000 died from the disease in 2014.

Ibrance works by inhibiting molecules, known as cyclin-dependent kinases (CDKs) 4 and 6, involved in promoting the growth of cancer cells. Ibrance is intended for postmenopausal women with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer who have not yet received an endocrine-based therapy. It is to be used in combination with letrozole, another FDA-approved product used to treat certain kinds of breast cancer in postmenopausal women.

“The addition of palbociclib to letrozole provides a novel treatment option to women diagnosed with metastatic breast cancer,” said Richard Pazdur, M.D., director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research. “The FDA is committed to expediting marketing approval of cancer drugs through our accelerated approval regulations.”

The FDA granted Ibrance breakthrough therapy designation because the sponsor demonstrated through preliminary clinical evidence that the drug may offer a substantial improvement over available therapies. It also received a priority review, which provides for an expedited review of drugs intended to provide a significant improvement in safety or effectiveness in the treatment of a serious condition or meet an unmet medical need. Ibrance is being approved more than two months ahead of the prescription drug user fee goal date of April 13, 2015, the date when the agency was scheduled to complete its review of the application.

Ibrance is being approved under the FDA’s accelerated approval program, which allows approval of a drug to treat a serious or life-threatening disease based on clinical data showing the drug has an effect on a surrogate endpoint reasonably likely to predict clinical benefit to patients. This program provides earlier patient access to promising new drugs while the company conducts confirmatory clinical trials.

The drug’s efficacy was demonstrated in 165 postmenopausal women with ER-positive, HER2-negative advanced breast cancer who had not received previous treatment for advanced disease. Clinical study participants were randomly assigned to receive Ibrance in combination with letrozole or letrozole alone. Participants treated with Ibrance plus letrozole lived about 20.2 months without their disease progressing (progression-free survival), compared to about 10.2 months seen in participants receiving only letrozole. Information on overall survival is not available at this time.

The most common side effects of the drug were a decrease in infection-fighting white blood cells called neutrophils (neutropenia), low levels of white blood cells (leukopenia), fatigue, low red blood cell counts (anemia), upper respiratory infection, nausea, inflammation of the lining of the mouth (stomatitis), hair loss (alopecia), diarrhea, low blood platelet counts (thrombocytopenia), decreased appetite, vomiting, lack of energy and strength (asthenia), damage to the peripheral nerves (peripheral neuropathy) and nosebleed (epistaxis). Healthcare professionals should inform patients of these risks.

It is recommended that treatment begin with a 125 milligram dose for 21 days, followed by seven days without treatment. Healthcare professionals are advised to monitor complete blood count prior to start of therapy and at the beginning of each cycle, as well as on Day 14 of the first two cycles, and as clinically indicated.

Ibrance is marketed by New York City-based Pfizer, Inc.

The FDA, an agency within the U.S. Department of Health and Human Services, promotes and protects the public health by, among other things, 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.