The US Food and Drug Administration (FDA) has granted approval for Agios Pharmaceuticals’ Tibsovo (ivosidenib) tablets to treat adults with relapsed or refractory acute myeloid leukaemia (AML) characterised by specific IDH1 gene mutations.

Said to be the first approved targeted therapy for AML, Tibsovo is indicated for use with an FDA-approved companion diagnostic developed to identify the IDH1 mutations.

Tibsovo is an isocitrate dehydrogenase-1 enzyme inhibitor designed to reduce abnormal production of the oncometabolite 2-hydroxyglutarate (2-HG), which can result in the differentiation of malignant cells.

Patients who have been found to possess the IDH1 mutation in blood or bone marrow samples analysed using an FDA-approved test may be eligible for therapy with the drug.

FDA Oncology Center of Excellence director Richard Pazdur said: “Tibsovo is a targeted therapy that fills an unmet need for patients with relapsed or refractory AML who have an IDH1 mutation.

“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.”

“Tibsovo is a targeted therapy that fills an unmet need for patients with relapsed or refractory AML who have an IDH1 mutation.”

The regulatory authority’s decision comes after its review of results from an open-label, single-arm, multi-centre dose-escalation and expansion clinical trial conducted in 174 patients with relapsed or refractory AML and an IDH1 mutation.

During the trial, the proportion of patients with no evidence of disease and full recovery of blood counts after treatment (complete remission or CR), and those with partial recovery of blood counts (complete remission with partial hematologic recovery or CRh) were measured.

It was observed that, with a median follow-up of 8.3 months, 32.8% of subjects experienced a CR or CRh lasting for a median of 8.2 months.

In addition, 37% of the 110 participants who needed blood or platelet transfusions due to AML at the start of the study did not require any transfusions for at least 56 days following Tibsovo treatment.

The FDA has also approved Abbott’s RealTime IDH1 Assay, which can be used as a companion diagnostic to detect the IDH1 gene mutations.