- 31.8% CR/CRh/CRi rate in primary induction failure and early relapsed AML patients
- Median duration of response = 8.13 months
In the open label study of flotetuzumab, 44 AML patients had disease classified as either PIF or ER6. Of these patients, 72.7% (32 of 44) had adverse risk cytogenetics by ELN Risk Stratification (2017). Patients were treated with flotetuzumab at the recommended Phase 2 dose (RP2D) of 500 ng/kg/day by continuous infusion. Data were reported as of the cut-off date of
The median time to achieve a response to flotetuzumab was one cycle (range of 1-3 cycles). Responses, including complete remission (CR), CRh (CR with partial hematological recovery) and CRi (CR with incomplete hematological improvement) per a modified
|PIF/ER (n=44)||PIF (n=27)||ER6 (n=17)|
|CR/CRh||25.0% (11)||33.3% (9)||11.8% (2)|
|CR/CRh/Cri||31.8% (14)||37.0% (10)||23.5% (4)|
|HSCT||57.1% (8/14)||70.0% (7/10)||25.0% (1/4)|
|Median Duration of Response||8.13 mos.
As shown in the table, over 50% of responders (8 of 14) successfully received allogeneic hematopoietic stem cell transplantation (HSCT) as consolidation therapy with durable remission (median not reached). Also, among those PIF/ER6 patients who achieved remission (CR, CRh or CRi), the median duration of response was 8.13 months, with a median overall survival of 10.7 months. Within the PIF/ER6 population, five of ten patients with TP53MUT AML achieved CR/CRh/CRi responses, three of whom went on to receive HSCT. More detailed flotetuzumab clinical data in the TP53MUT AML population is available via a separate poster presentation at ASH (see “TP53 Abnormalities Correlate with Immune Infiltration and Associate with Response to Flotetuzumab Immunotherapy in Acute Myeloid Leukemia”, Session 617).
The most common treatment-related adverse event (TRAE) was infusion-related reaction/cytokine release syndrome (IRR/CRS), which occurred in all patients. However, most CRS events observed were of short duration and mild to moderate (Grade 1 or 2) in severity, with only a single Grade 3 event reported.
“For the approximately 50% of AML patients who fail primary induction therapy or relapse within six months of an initial response, there is no standard of care among the available treatment regimens. Historically, these patients have CR/CRh rates to subsequent interventions in the range of only 5-12% with a median overall survival of approximately 3.5 months. A remission rate of 32% with good duration and a manageable safety profile observed to date in the ongoing registrational study of flotetuzumab in this extremely challenging patient population is very encouraging,” said Ibrahim Aldoss, M.D., Assistant Professor of Hematology/HCT at
In addition to the above data provided in an oral presentation, five additional presentations related to flotetuzumab and AML have or will be presented at ASH.
“We are very encouraged by the updated results from this study, and continue to enroll patients in this single arm, registrational trial,” said
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
Flotetuzumab (previously known as MGD006) is a clinical-stage bispecific, investigational 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.
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Source: MacroGenics, Inc.