The U.S. Food and Drug Administration (FDA) approved Idhifa (enasidenib) for treating patients with relapsed or refractory acute myeloid leukemia (AML) who have mutations in their IDH2 gene. The FDA also approved the RealTime IDH2 Assay, necessary to detect IDH2 gene mutations in AML patients.
AML is an aggressive, difficult-to-treat rare blood cancer that forms in the bone marrow and leads to increased number of abnormal white blood cells. Each year, over 21,000 people will be diagnosed with AML and over 10,000 patients will die from it. IDH2 mutations are present in 8 – 19% of AML patients.
Idhifa (enasidenib) inhibits isocitrate dehydrogenase-2, an enzyme involved in cell growth.
“Idhifa is a targeted therapy that fills an unmet need for patients with relapsed or refractory AML who have an IDH2 mutation,” said Richard Pazdur, M.D., director of the FDA’s Oncology Center of Excellence and acting director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research in a news release
The approval of Idhifa was based on a single-arm trial of 199 patients with relapsed or refractory AML who had IDH2 mutations. With a minimum of 6 months of treatment, 19% of patients experienced complete remission for a median 8.2 months, and 4% experienced complete remission with partial hematologic recovery for a median 9.6 months.
Additionally, more than one-third of the 157 patients who required transfusions at the start of the study, no longer required transfusions after receiving Idhifa.
Common side effects of the drug include nausea, vomiting, diarrhea, increased levels of bilirubin, and decreased appetite. Women who are pregnant or breastfeeding should not take it because it may cause harm to a developing fetus or a newborn baby.
A boxed warning will be included in the prescribing information for Idhifa stating that differentiation syndrome can occur and can be fatal if not treated. Sign and symptoms of differentiation syndrome may include fever, difficulty breathing (dyspnea), acute respiratory distress, inflammation in the lungs (radiographic pulmonary infiltrates), fluid around the lungs or heart (pleural or pericardial effusions), rapid weight gain, swelling (peripheral edema) or liver (hepatic), kidney (renal) or multi-organ dysfunction.
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