FDA approves Tibsovo (ivosidenib) for myelodysplastic syndromes

The FDA also approved the Abbott RealTime IDH1 Assay as a companion diagnostic device to select patients for ivosidenib.

Approval was based on trial AG120-C-001 (NCT02074839), an open-label, single-arm, multicenter trial of 18 adult patients with relapsed or refractory MDS with an IDH1 mutation. IDH1 mutations were detected in peripheral blood or bone marrow by a local or central diagnostic test and confirmed retrospectively by the Abbott RealTime IDH1 Assay.

Ivosidenib was administered orally at a starting dose of 500 mg daily continuous for 28-day cycles until disease progression, unacceptable toxicity, or hematopoietic stem cell transplantation. The median treatment duration was 9.3 months. One patient underwent a stem cell transplantation following ivosidenib.

Efficacy was established by the rate of complete remission (CR) or partial remission (PR) (2006 International Working Group response for MDS), CR+PR durations, and conversion rate from transfusion dependence to independence. All observed responses were CRs. The CR rate was 38.9% (95% CI: 17.3, 64.3). The median time-to-CR was 1.9 months (range, 1.0 to 5.6 months) and the median CR duration was not estimable (range 1.9, 80.8+ months). Among 9 patients dependent on red blood cell (RBC) and/or platelet transfusions at baseline, 6 (67%) became RBC and platelet transfusion independent during any 56-day post-baseline period. Of the 9 patients independent of both RBC and platelet transfusions at baseline, 7 (78%) remained transfusion independent during any 56-day post-baseline period.