FDA approves Celgene and Agios' acute myeloid leukaemia drug

Idhifa is an isocitrate dehydrogenase-2 (IDH2) inhibitor which works by blocking a number of enzymes which promote cell growth. Mutations in the IDH2 gene are identified in blood or bone marrow samples using RealTime IDH2 Assay, a companion diagnostic, and the drug is approved for use with this tool.

The decision to approve the drug was based on the results of a study of 199 participants with relapsed or refractory AML with IDH2 mutations. It was found that after a minimum of six months of treatment, 19% of patients experienced complete remission for a median of 8.2 months, and 4% achieved complete remission with partial haematologic recovery for a median 9.6 months. At the beginning of the study, 157 participants required blood or platelet transfusions; following treatment with Idhifa, 34% no longer required such transfusions.

The drug comes with a boxed warning over the risk that usage may lead to differentiation syndrome, a common but severe adverse reaction in AML patients which is characterised by fever, imflammation of the lungs and difficulty breathing, liver, kidney or multi-organ dysfunction, among others.

"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, 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. "The use of Idhifa was associated with a complete remission in some patients and a reduction in the need for both red cell and platelet transfusions."