MacroGenics, Inc. a clinical-stage biopharmaceutical company focused on discovering and developing innovative monoclonal antibody-based therapeutics for the treatment of cancer, as well as autoimmune disorders and infectious diseases, today announced the presentation of clinical data from its Phase 1 study of flotetuzumab in an oral session at the European Society for Medical Oncology Annual Congress, ESMO 2017, in Madrid, Spain. Norbert Vey, M.D., Team Leader Translational Medicine – Hematology at Institut Paoli-Calmettes, Marseille, France, presented "Interim Results from a Phase 1 First-in-Human study of flotetuzumab, a CD123 x CD3 bispecific DART molecule, in AML/MDS."
The ongoing Phase 1, first-in-human, dose-escalation study was designed to determine safety, tolerability, maximum tolerated dose and initial anti-leukemic activity of flotetuzumab in patients with relapsed or refractory acute myeloid leukemia (AML) or intermediate-2/high risk myelodysplastic syndrome (MDS).
Flotetuzumab demonstrated acceptable tolerability in the dose escalation portion of the study. Infusion-related reaction and cytokine release syndrome (CRS) were the most common adverse events observed, with Grade 3 CRS occurring in 6 of 47 patients (12.8%). A two-step, lead-in dose as well as early intervention with anti-cytokine therapy was implemented to limit the severity and incidence of CRS.
Encouraging initial anti-leukemic activity has been observed in patients treated at the threshold flotetuzumab dose of 500ng/kg/day or greater. As of the data cut-off date, of the 14 response-evaluable patients treated at this dose, eight (57%) patients had anti-leukemic activity, with six (43%) of these patients experiencing an objective response. This included four (28%) patients who experienced CR/CRi, with one patient who experienced a molecular CR. In the majority of patients who responded, anti-leukemic activity was observed after a single cycle of therapy.
"MacroGenics is pleased with the encouraging data from this ongoing Phase 1 study of flotetuzumab, our first clinical DART molecule focused on T-cell redirected killing," said Scott Koenig, M.D., Ph.D., President and CEO of MacroGenics. "Enrollment of the AML and MDS dose-expansion cohorts at the selected dose and schedule are well under way and we expect to present updated clinical data at an additional scientific conference later this year.”
