The U.S. Food and Drug Administration today approved enasidenib for the treatment of adult patients with relapsed or refractory acute myeloid leukaemia (AML) who have a specific genetic mutation.

The drug is approved for use with a companion diagnostic, the RealTime IDH2 Assay, which is used to detect specific mutations in the IDH2 gene in patients with AML.

“Enasidenib 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 Haematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research. “The use of enasidenib was associated with a complete remission in some patients and a reduction in the need for both red cell and platelet transfusions.”

AML is a rapidly progressing cancer that forms in the bone marrow and results in an increased number of abnormal white blood cells in the bloodstream and bone marrow.

The National Cancer Institute at the National Institutes of Health estimates that approximately 21,380 people will be diagnosed with AML this year; approximately 10,590 patients with AML will die of the disease in 2017.

Idhifa is an isocitrate dehydrogenase-2 inhibitor that works by blocking several enzymes that promote cell growth.

If the IDH2 mutation is detected in blood or bone marrow samples using the RealTime IDH2 Assay, the patient may be eligible for treatment with enasidenib.

The efficacy of enasidenib was studied in a single-arm trial of 199 patients with relapsed or refractory AML who had IDH2 mutations as detected by the RealTime IDH2 Assay.

The trial measured the percentage of patients with no evidence of disease and full recovery of blood counts after treatment (complete remission or CR), as well as patients with no evidence of disease and partial recovery of blood counts after treatment (complete remission with partial hematologic recovery or CRh).

With a minimum of six months of treatment, 19 percent of patients experienced CR for a median 8.2 months, and 4 percent of patients experienced CRh for a median 9.6 months.

Of the 157 patients who required transfusions of blood or platelets due to AML at the start of the study, 34 percent no longer required transfusions after treatment with enasidenib.

Common side effects of enasidenib include nausea, vomiting, diarrhoea, increased levels of bilirubin (substance found in bile) and decreased appetite.

Women who are pregnant or breastfeeding should not take enasidenib because it may cause harm to a developing foetus or a newborn baby.

Source: FDA