MacroGenics announces updated results from Phase 1/2 study of flotetuzumab
MacroGenics announced updated results from a Phase 1/2 dose expansion study of flotetuzumab, an investigational, bispecific CD123 x CD3 DART molecule in patients with primary induction failure and early relapsed acute myeloid leukemia, or AML. The data were presented in an oral session at the 61st Annual Meeting of the American Society of Hematology, or ASH. In the Phase 1/2 open-label, dose expansion study, 30 patients classified as primary induction failure or early relapsed AML who had received a median of four prior therapies were treated with flotetuzumab at the recommended phase 2 dose of 500 ng/kg/day by continuous infusion. Data were reported as of the cut-off date of November 1, 2019. The study is currently ongoing, with additional patients being enrolled. Responses, including complete remission, CR with partial hematological recovery and CR with incomplete hematological improvement per a modified International Working Group Response Criteria for AML were summarized. Four responders received allogeneic hematopoietic stem cell transplantation as consolidation therapy and remain in remission after 6 to 21 months. The most common treatment-related adverse event (TRAE) was infusion-related reaction/cytokine release syndrome that occurred in all 30 patients. However, most CRS events observed were of short duration and mild to moderate in severity, with only one grade 3 event reported in one patient, the company said. "Based on the encouraging data from this study, and pending anticipated discussions with the FDA in the first half of 2020, we are planning for a potential registration-enabling study of flotetuzumab in this high unmet need population of patients with refractory AML, who have limited treatment options," said Scott Koenig, President and CEO of MacroGenics.