FDA Approves First Targeted Treatment for Certain Patients with Acute Myeloid Leukemia

The US Food and Drug Administration (FDA) has approved the first drug in its class (IDH1 inhibitors), ivosidenib (Tibsovo), for the treatment of adult patients with relapsed or refractory acute myeloid leukemia (AML) who have a specific genetic mutation. The drug is also approved for use with an FDA-approved companion diagnostic to detect specific mutations in the IDH1 gene in patients with AML.

“Tibsovo is a targeted therapy that fills an unmet need for patients with relapsed or refractory AML who have an IDH1 mutation,” said Richard Pazdur, MD, 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 recent statement. “The use of Tibsovo is associated with a complete remission in some patients and a reduction in the need for both red cell and platelet transfusions.”

Ivosidenib is an isocitrate dehydrogenase-1 inhibitor that works by decreasing abnormal production of the oncometabolite 2-hydroxyglutarate (2-HG), leading to differentiation of malignant cells. A patient may be eligible for ivosidenib treatment if, by using an FDA-approved test, the IDH1 mutation is detected in blood or bone marrow samples. The mutation can be detected with the RealTime IDH1 Assay, a companion diagnostic also approved today.

A single-arm trial of 174 adult patients with relapsed or refractory AML with an IDH1 mutation serves as the basis for the approval.

The percentage of patients with no evidence of disease and full recovery of blood counts following 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) included primary measurements in the trial.

A CR or CRh that lasted a median 8.2 months was experienced by 32.8% of patients with a median follow-up of 8.3 months. Additionally, 37% went at least 56 days without requiring a transfusion after treatment with ivosidenib of the 110 patients who required transfusions of blood or platelets due to AML at the start of the study.

Fatigue, increase in white blood cells, joint pain, diarrhea, shortness of breath, swelling in the arms or legs, nausea, pain or sores in the mouth or throat, irregular heartbeat (QT prolongation), rash, fever, cough, and constipation and constipationn include common side effects with ivosidenib. As ivosidenib can harm newborn babies via breastfeeding, women who are nursing should not take the ivosidenib.

A QT prolongation, which can be life-threatening, is another serious warning. An electrocardiogram should be used to test the electrical activity of the heart during treatment. Guillain-Barré syndrome, a rare neurological disorder, should be also be monitored for so as to avoid nervous system issues.

Ivosidenib has previously received fast track, priority review, and orphan drug designations.