FDA grants Oxi4503 rare pediatric disease designation for the treatment of children with AML

On September 16, 2020, the U.S. Food and Drug Administration (FDA) granted OXi4503 rare pediatric drug designation for the treatment of acute myeloid leukemia (AML) due to genetic mutations that disproportionately affect pediatric patients.¹

This designation was based on the phase Ib study (NCT02576301) of OXi4503 as a single agent and in combination with intermediate-dose cytarabine for adult patients with relapsed/refractory AML or myelodysplastic syndrome. Of the 26 evaluable patients with AML, ~17% reached complete remission and had a median overall survival of 528 days. The combination therapy showed a manageable toxicity profile, and 8.5 mg/m² OXi4503 was identified as the maximum tolerated dose.¹

OXi4503 is a vascular disrupting agent. It binds to tubulin at the colchicine binding site, thus disrupting the shape of tumor bone marrow endothelial cells, activating the cell cycle and making the tumor cells vulnerable to chemotherapy. It also directly kills tumor cells by myeloperoxidase activation of a fluorquinone cytotoxic mediator.²