FDA Expands Approval of Rx for Rare Blood and Bone Disease

Imbruvica approved to treat chronic lymphocytic leukemia

(RxWiki News) Earlier this year, the US Food and Drug Administration (FDA) gave a speedy approval to a new medication to treat a rare blood disease. Now, the FDA has expanded that approval.

This past February, the FDA gave accelerated approval to Imbruvica (ibrutinib) to treat chronic lymphocytic leukemia (CLL).

Based on a new clinical trial, the FDA has broadened the approved use of Imbruvica to treat CLL patients with a certain chromosome deletion (17p deletion). This genetic issue has been linked to poorer responses to standard CLL treatment.

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Based on the results from that same clinical trial, the FDA has verified its approval of Imbruvica to treat CLL. In other words, the accelerated approval was based on limited evidence. But with the recent clinical trial, researchers were able to see that the medication improved time until disease got worse and death risk.

The FDA also has approved new labeling on Imbruvica to reflect these findings.

CLL is a rare blood and bone marrow disease. In most cases, CLL slowly worsens over time. According to estimates from the National Cancer Institute, more than 15,000 Americans will be diagnosed with CLL in 2014, and 4,600 of those people will die from the disease.

“We continue to see advances in the availability of therapies to treat chronic lymphocytic leukemia, especially for difficult-to-treat patient populations,” said Richard Pazdur, MD, director of the Office of Hematology and Oncology Products in the FDA's Center for Drug Evaluation and Research, in an FDA press release.

"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," Dr. Pazdur said.

The clinical trial behind both of these recent approval actions included 391 CLL patients who had already received treatment. Of these patients, 127 had the 17p deletion. These patients were randomly assigned to receive either Imbruvica or another CLL medication called Arzerra (ofatumumab).

The researchers ended the trial early because of the success they saw with Imbruvica. Overall, regardless of whether patients had the 17p deletion or not, those treated with Imbruvica had a 78 percent drop in disease progression or death (progression-free survival) and a 57 percent drop in death risk (overall survival).

The trial results showed a similar decrease in risk among solely the patients with the 17p deletion who were treated with Imbruvica. These patients had a 75 percent drop in risk of disease progression or death.

Imbruvica did come with some side effects. The most common of these side effects were low platelet levels (thrombocytopenia), a drop in infection-fighting white blood cells called neutrophils (neutropenia), diarrhea, anemia, fatigue, muscle and bone pain, upper respiratory tract infection, rash, nausea and fever.

Imbruvica is marketed by both Pharmacyclics and Janssen Biotech.

Review Date: 
July 28, 2014