FDA Approves First Therapy for Rare Form of MDS

The Food and Drug Administration recently approved ivosidenib (Tibsovo, Servier) to treat adult patients with relapsed or refractory (R/R) myelodysplastic syndromes (MDS) with an isocitrate dehydrogenase-1 mutation as detected by an FDA-approved test. The agency also approved the Abbott RealTime IDH1 Assay as a companion diagnostic for the selection of R/R MDS patients with an IDH1 mutation.

Ivosidenib is the first targeted therapy approved for MDS with an IDH1 mutation, a rare form of blood cancer that can occur when the mutations in the bone marrow progenitor cells lead to insufficient numbers of healthy blood cells.

FDA based its approval on findings from an open-label, single-arm study of 18 adult patients with R/R MDS with an IDH1 mutation. Ivosidenib was given orally at a starting dose of 500 milligram daily continuous for 28-day cycles until disease progression, development of unacceptable toxicity or undergoing bone marrow transplantation.

In the trial, 39% of patients had a complete or partial remission at the end of the study period. All observed responses were complete remissions, and the median duration of complete remission ranged from 1.9 to 80.8 months. For patients who achieved a complete remission, the median time to complete remission was 1.9 months. Among the nine patients who required transfusions of blood or platelets due to MDS at the start of the study, six (67%) no longer required transfusions after treatment.

In the U.S., FDA previously approved ivosidenib for certain adults with newly diagnosed acute myeloid leukemia (AML), relapsed or refractory AML and locally advanced or metastatic cholangiocarcinoma. The Abbott RealTime IDH1 Assay is also approved as a companion diagnostic to identify AML patients with an IDH1 mutation for treatment with ivosidenib or olutasidenib (Rezlidhia).