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München, Germany

Zugmaier G.,Amgen | Klinger M.,Amgen | Schmidt M.,Amgen | Subklewe M.,Ludwig Maximilians University of Munich | Subklewe M.,Helmholtz Institute Munich
Molecular Immunology | Year: 2015

Blinatumomab, a bispecific antibody construct targeting CD19, is the most advanced member of bispecific T-cell engager (BiTE®) molecules. The clinical development program includes B-precursor acute lymphoblastic leukemia (ALL) and B-cell non-Hodgkin lymphoma (NHL). Minimal residual disease (MRD) response in patients with MRD-positive B-precursor ALL has translated into long-term clinical benefits as demonstrated by an estimated relapse-free survival (RFS) of 60% with sustained MRD negativity at a follow-up of 31 months. Remissions induced in pediatric and adult patients with relapsed/refractory B-precursor ALL have allowed for successful allogeneic hematopoietic stem cell transplantation (HSCT) in this setting. Blinatumomab has also induced durable responses in low-grade B-cell NHL. Blinatumomab recently gained approval in the United States by the U.S. Food and Drug Administration for treatment of Philadelphia chromosome-negative B-precursor relapsed/refractory acute lymphoblastic leukemia. AMG 330 is an investigational anti-CD33 BiTE® antibody construct. Targeting CD33 ex vivo in primary samples from patients with acute myeloid leukemia (AML) has shown AMG 330-mediated T-cell expansion and T-cell cytotoxicity against AML cells. © 2015 Elsevier Ltd. Source


Krupka C.,Ludwig Maximilians University of Munich | Krupka C.,Helmholtz Institute Munich | Kufer P.,Amgen | Kischel R.,Amgen | And 20 more authors.
Blood | Year: 2014

Antibody-based immunotherapy represents a promising strategy to target and eliminate chemoresistant leukemic cells. Here, we evaluated the CD33/CD3-bispecific T cell engaging (BiTE) antibody (AMG 330) for its suitability as a therapeutic agent in acute myeloid leukemia (AML). We first assessed CD33 expression levels by flow cytometry and found expression in >99% of patient samples (n = 621). CD33 was highest expressed in AMLs with NPM1 mutations (P < .001) and lower in AMLs with complex karyotypes and t(8;21) translocations (P < .001). Furthermore, leukemic stem cells within the CD34+/ CD38- compartment displayed CD33 at higher levels than healthy donor stem cells (P = .047). In MS-5 feeder cell-based long-term cultures that supported the growth of primary AML blasts for up to 36 days, AMG 330 efficiently recruited and expanded residual CD3 +/CD45RA-/CCR7+ memory T cells within the patient sample. Even at low effector to target ratios, the recruited T cells lysed autologous blasts completely in the majority of samples and substantially in the remaining samples in a time-dependent manner. This study provides the first correlation of CD33 expression levels with AML genotype in a comprehensive analysis of adult patients. Targeting CD33 ex vivo using AMG 330 in primary AML samples led to T cell recruitment and expansion and remarkable antibody-mediated cytotoxicity, suggesting efficient therapeutic potential in vivo. © 2014 by The American Society of Hematology. Source


Schnorfeil F.M.,Ludwig Maximilians University of Munich | Schnorfeil F.M.,Helmholtz Institute Munich | Lichtenegger F.S.,Ludwig Maximilians University of Munich | Lichtenegger F.S.,Helmholtz Institute Munich | And 11 more authors.
Journal of Hematology and Oncology | Year: 2015

Background: T cell function is crucial for the success of several novel immunotherapeutic strategies for the treatment of acute myeloid leukemia (AML). However, changes in phenotype and function of T cells have been described in various hematologic malignancies, mimicking T cell exhaustion known from chronic viral infections. Detailed knowledge about phenotype and function of T cells in AML patients at different stages of the disease is indispensable for optimal development and application of immunotherapeutic strategies for this disease. Methods: We used flow cytometry-based assays to characterize T cell phenotype and function in peripheral blood and bone marrow of AML patients at diagnosis, at relapse after intensive chemotherapy, and at relapse after allogeneic stem cell transplantation (SCT). Surface expression of CD244, PD-1, CD160, and TIM-3 was determined, and proliferation and production of IFN-γ, TNF-α, and IL-2 were measured. Results: We detected similar expression of inhibitory molecules on T cells from patients at diagnosis and from age-matched healthy controls. At relapse after SCT, however, PD-1 expression was significantly increased compared to diagnosis, both on CD4+ and CD8+ T cells. This pattern was not associated with age and cytomegalovirus (CMV) status but with a shift towards effector memory cells in relapsed AML patients. Proliferation and cytokine production assays did not reveal functional defects in T cells of AML patients, neither at diagnosis nor at relapse. Conclusion: We thus conclude that T cell exhaustion does not play a major role in AML. Immunotherapeutic strategies targeting autologous T cells thus have particularly good prospects in the setting of AML. © 2015 Schnorfeil et al. Source

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