MacroGenics Announces Presentation of Flotetuzumab Translational Data at the 2020 AACR Annual Meeting

Rockville, MD, April 27, 2020 (GLOBE NEWSWIRE) --

MacroGenics, Inc. (NASDAQ: MGNX), a clinical-stage biopharmaceutical company focused on discovering and developing innovative monoclonal antibody-based therapeutics for the treatment of cancer, today announced data related to flotetuzumab, an investigational, bispecific CD123 x CD3 DART® molecule being evaluated in patients with refractory acute myeloid leukemia (AML). The data will be presented during a plenary session at the American Association for Cancer Research (AACR) Virtual Annual Meeting I, taking place April 27-28, 2020.

“Patients with TP53 mutated AML respond poorly to induction therapy and have a dismal prognosis. The current study suggests that TP53 mutational status correlated with an immune-infiltrated tumor microenvironment that was associated with response to flotetuzumab in our ongoing Phase 1/2 study in refractory disease,” said Scott Koenig, M.D., Ph.D., President and CEO of MacroGenics. “This analysis further elucidates potential immune drivers of response to flotetuzumab and supports its potential for treating patients with particularly challenging disease and who have limited treatment options.”

The current study was conducted by Professor Sergio Rutella, M.D., Ph.D., FRCPath, at the John van Geest Cancer Research Centre at Nottingham Trent University in the UK, in collaboration with MacroGenics and NanoString Technologies, Inc. The data suggests that TP53 mutations in AML associate with an immune-infiltrated tumor microenvironment (TME) characterized by high expression of IFN-γ signaling molecules and immune checkpoints. This inflammation signature was previously found to be associated with response to flotetuzumab immunotherapy in a Phase 1/2 study in patients with AML who were refractory to induction treatment (primary induction failure). In this new study, among patients with TP53 mutated AML who were treated with flotetuzumab, 45.5% (5/11) showed evidence of anti-leukemic activity, including two patients with complete remission (CR), one patient with a CR with partial hematologic recovery (CRh), and one patient with morphologic leukemia-free state (MLFS) per International Working Group (IWG) criteria. Furthermore, median overall survival (OS) of flotetuzumab-treated patients with TP53 abnormalities was 4 months (range 1.25-21.25), compared to an estimated median OS of 1 month (Stichting Hemato-Oncologie voor Volwassenen Nederland, HOVON, Rotterdam, NL).

AACR Virtual Presentation

Title: TP53 abnormalities correlate with immune infiltration and are associated with response to flotetuzumab, an investigational immunotherapy, in acute myeloid leukemia

Session: VCTPL03 - Immunotherapy Clinical Trials 1

Date: April 27, 2020

Time: 1:25 pm - 1:35 pm ET

Location: AACR Virtual Annual Meeting I at

After the presentation, Dr. Rutella’s slides will be available on the Events & Presentations page on MacroGenics’ website at .

About Acute Myeloid Leukemia

AML is a hematological malignancy characterized by differentiation arrest and uncontrolled clonal proliferation of neoplastic precursors that prevent normal bone marrow hematopoiesis. Nearly 20,000 new cases of AML are diagnosed in the U.S. each year, with a median age of 69 years at diagnosis. Approximately 40-50% of newly diagnosed patients fail to achieve a complete remission with intensive induction therapy (primary induction failure) or experience disease recurrence after a short remission duration (<6 months; early relapsed). A very small number of these patients are expected to respond to salvage therapy. Although new targeted agents have been approved for the treatment of frontline or relapsed/refractory AML in recent years, approximately 50% of patients have no known targetable mutations.

About Flotetuzumab

Flotetuzumab (also known as MGD006) is a clinical-stage bispecific DART molecule that recognizes both CD123 and CD3. CD123, the interleukin-3 receptor alpha chain, has been reported to be over-expressed on malignant cells in AML and other hematologic malignancies. The primary mechanism of action of flotetuzumab is believed to be its ability to redirect T lymphocytes to kill CD123-expressing cells. To achieve this, the DART molecule combines a portion of an antibody recognizing CD3, an activating molecule expressed by T cells, with an arm that recognizes CD123 on the target cells.

Flotetuzumab is currently being evaluated in the U.S. and Europe in a Phase 1/2 study (NCT02152956) designed to assess the safety, tolerability, and initial anti-leukemic activity of the molecule in patients with relapsed/refractory AML. Data from the ongoing clinical study were in December 2019 at the American Society of Hematology (ASH) Annual Meeting. The U.S. Food and Drug Administration has granted orphan drug designation to flotetuzumab for the treatment of AML. Pending discussions with FDA, MacroGenics plans to define a registration path for flotetuzumab in the U.S. for patients with AML who are refractory to induction treatment (primary induction failure) in the first half of 2020.

About MacroGenics, Inc.

MacroGenics is a clinical-stage biopharmaceutical company focused on discovering and developing innovative monoclonal antibody-based therapeutics for the treatment of cancer. The Company generates its pipeline of product candidates primarily from its proprietary suite of next-generation antibody-based technology platforms, which have applicability across broad therapeutic domains. The combination of MacroGenics' technology platforms and protein engineering expertise has allowed the Company to generate promising product candidates and enter into several strategic collaborations with global pharmaceutical and biotechnology companies. For more information, please see the Company's website at MacroGenics, the MacroGenics logo and DART are trademarks or registered trademarks of MacroGenics, Inc.

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