FDA Approves Ivosidenib for Subtype of Acute Myeloid Leukemia

The FDA has approved the oral IDH1 inhibitor ivosidenib (Tibsovo) for the treatment of adult patients with relapsed/refractory IDH1-mutant acute myeloid leukemia (AML).

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

The approval was based on a single-arm phase I study of 174 patients with IDH1-positive relapsed/refractory AML. In the study, the complete remission (CR) rate was 24.7% (n = 43; 95% CI, 18.5-31.8) and the CR with partial hematologic improvement (CRh) rate was 8% (n = 14; 95% CI, 4.5-13.1). The median duration of CR plus CRh was 8.2 months (range, 5.6-12). Among the CR/CRh population, the median time to best response was 2.0 months (range, 0.9-5.6).

The median patient age in the pivotal trial was 67 years (range, 18-87) and patients had received a median of 2 prior therapies (range, 1-6). Thirty-three percent of patients had secondary AML and 63% were refractory to their previous therapy. IDH1 mutations were identified/confirmed by the Abbott RealTime™ IDH1 assay.

Common adverse effects of Tibsovo include 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. Nursing mothers should not take Tibsovo because it may cause harm to a newborn baby.

In a statement on the approval, Hagop M. Kantarjian, MD, professor and chair of the Department of Leukemia at The University of Texas MD Anderson Cancer Center, said, “AML patients who relapse or are refractory to available therapies have few, if any, treatment options. The clinical study demonstrated that Tibsovo has the potential to deliver strong, durable responses as a single agent and can help patients achieve and maintain transfusion independence. IDH inhibitors represent a new class of noncytotoxic, targeted therapies for AML patients with IDH mutations.”

Reference

FDA Grants Approval of TIBSOVO®, the First Oral, Targeted Therapy for Adult Patients with Relapsed/Refractory Acute Myeloid Leukemia and an IDH1 Mutation. Agios. Published July 20, 2018. Accessed July 20, 2018. https://bit.ly/2mwqScv.