The U.S. Food and Drug Administration today expanded the approved use of Exjade (deferasirox) to treat patients ages 10 years and older who have chronic iron overload resulting from a genetic blood disorder called non-transfusion-dependent thalassemia (NTDT).
NTDT is a milder form of thalassemia that does not require individuals to get frequent red blood cell transfusions. However, over time, some patients with NTDT are still at risk for iron overload that can lead to damage to vital organs.
The FDA is also authorizing marketing of FerriScan as an imaging companion diagnostic for Exjade. The agency previously cleared FerriScan for measuring liver iron concentration (LIC), but its use in Exjade clinical studies to select patients for therapy, and to manage therapy, defined its role as an imaging companion diagnostic necessary for Exjade's safe and effective use. FerriScan measures LIC non-invasively using magnetic resonance imaging.
An estimated 1,000 people in the United States have thalassemia, according to the National Heart, Lung, and Blood Institute. Thalassemia conditions can cause the body to make fewer healthy red blood cells and less hemoglobin, a protein that carries oxygen to all parts of the body and returns carbon dioxide to the lungs so it can be exhaled. Some patients with thalassemia require frequent transfusions of red blood cells to maintain an acceptable level of hemoglobin. Iron overload is common in these patients.
Exjade was previously approved for treatment of chronic iron overload due to blood transfusions in patients ages 2 years and older, and this approval extends its use to treat patients with NTDT who show iron overload. Exjade should be used in patients with NTDT who have an LIC of at least 5 milligrams of iron per gram of dry liver tissue weight.
Exjade's new indication is being approved under the FDA's accelerated approval program, which provides patients earlier access to promising new drugs intended to treat serious or life-threatening illnesses while the company conducts additional studies to confirm the drug's clinical benefit. Exjade was approved based on clinical data showing it can reduce LIC to less than 5 mg/g dry weight, a surrogate endpoint that is judged reasonably likely to predict a clinical benefit to patients.
"Using our accelerated approval process, FDA is able to expedite the availability of this drug to patients who need to reduce excess iron," said Richard Pazdur, M.D., director of the Office of Hematology and Oncology Products in the FDA's Center for Drug Evaluation and Research. "Exjade is the first drug approved to treat patients with NTDT who show iron overload."
The safety and effectiveness of Exjade to treat chronic iron overload in patients with NTDT were established in two clinical trials designed to measure the number of patients whose LIC was reduced to less than 5 mg/g dry weight after 52 weeks of treatment. In the first trial, 166 patients were randomly assigned to receive 5 mg/kg of Exjade, 10 mg/kg of Exjade, or a placebo daily. Results showed 15 percent and 27 percent of Exjade-treated patients achieved the target LIC, respectively, compared with 4 percent in placebo-treated patients. The second trial contained 133 patients from the first study who received an additional year of Exjade treatment or switched from placebo to Exjade treatment. Thirty-five percent of the evaluable patients in this extension trial achieved the target LIC.
The FDA reviewed data for the FerriScan through the de novo classification process, a regulatory pathway for medical devices that are generally moderate-risk but are not comparable to an already legally marketed device. The FDA's granting of the de novo request for FerriScan was based largely on data from the Exjade clinical studies that used FerriScan LIC results as the primary outcome measure. Additionally, investigators conducted a 230-patient study that found FerriScan results were as accurate as liver biopsy for measuring LIC.
"The FerriScan device is a non-invasive test that helps physicians to select appropriate patients for Exjade therapy as well as monitor their response to the drug, and discontinue therapy when LIC reaches safe levels," said Alberto Gutierrez, Ph.D., director of the Office of In Vitro Diagnostics and Radiological Health in the FDA's Center for Devices and Radiological Health.
Exjade is marketed by East Hanover, N.J.-based Novartis. FerriScan is marketed by Resonance Health, based in Australia.