The FDA has expanded the use of Imbruvica (ibrutinib) to treat patients with chronic lymphocytic leukemia (CLL) who carry a deletion in chromosome 17 (17p deletion), and thus have shown poor responses to standard treatment for the disease. The news comes just 9 months after Imbruvica was given accelerated approval for the treatment of patients with mantle cell lymphoma who have received at least one prior therapy. While the agency noted that clinical studies to verify and describe Imbruvica’s clinical benefit in mantle cell lymphoma are ongoing, new trial results examining progression-free survival and overall survival have confirmed the drug’s clinical benefit giving it “breakthrough”therapy status.
CLL is a non-Hodgkin lymphoma, affecting the blood and bone marrow. It usually gets progressively worse slowly over time, causing a gradual increase in white blood cells called B lymphocytes, or B cells. According to the National Cancer Institute, approximately 15,720 people in the United States will be diagnosed and 4,600 will die from CLL this year alone. Imbruvica works by blocking the enzyme that allows cancer cells to grow and divide.
The most common side effects associated with Imbruvica observed in the clinical study include low levels of platelets in the blood, a decrease in infection-fighting white blood cells called neutrophils, as well as anemia (low red-blood cell count), diarrhea, fatigue, pain in the muscles and bones, upper respiratory tract infection, rash, nausea and fever.
“We continue to see advances in the availability of therapies to treat chronic lymphocytic leukemia, especially for difficult-to-treat patient populations,” stated Dr. Richard Pazdur, M.D., director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research. “Imbruvica is the fourth drug approved to treat CLL that received a breakthrough therapy designation, reflecting the promise of the breakthrough therapy designation program and demonstrating the FDA’s commitment to working cooperatively with companies to expedite the development, review and approval of these important new drugs.”
The other three drugs approved to treat CLL that received breakthrough designations are Gazyva (obinutuzumab) in November 2013, Arzerra (ofatumumab) in April 2014 and Zydelig (idelalisib) in July 2014.