Anti-CD33 mAb (BI 836858)

CD33 is a cell adhesion molecule found only on the surface of haematopoietic cells, primarily cells of myeloid lineage, including monocytes, granulocytes and dendritic cells but is absent on haematopoietic stem cells.1,2 High CD33 expression is seen on malignant cells in acute myeloid leukemia (AML), which makes CD33 an ideal therapeutic target for the treatment of AML.1

Boehringer Ingelheim is currently investigating BI 836858, an anti-CD33 monoclonal antibody (mAb), which has been engineered for improved binding to FcgRIIIa to mediate natural killer (NK) cell antibody-dependent cellular cytotoxicity (ADCC).3

Preclinical studies with this fully human IgG1 mAb have shown NK-mediated ADCC against malignant CD33+ AML blast cells.3 BI 836858 is currently being investigated in Phase I/II trials for the treatment of myeloid malignancies, AML4 and myelodyplastic syndromes (MDS).5

References: 
  1. Ehninger A, Kramer M, Rollig C, et al. Distribution and levels of cell surface expression of CD33 and CD123 in acute myeloid leukemia. Blood Cancer J 2014;4:e218.
  2. Nguyen DH, Ball ED, Varki A. Myeloid precursors and acute myeloid leukemia cells express multiple CD33-related Siglecs. Exp Hematol 2006;34(6):728–735.
  3. Vasu S, He S, Cheney C, et al. Decitabine enhances anti-CD33 monoclonal antibody BI 836858-mediated natural killer ADCC against AML blasts. Blood 2016;127(23):2879–2889.
  4. ClinicalTrials.gov. NCT02632721. https://clinicaltrials.gov/ct2/show/study/NCT02632721 (Accessed: August 2016).
  5. ClinicalTrials.gov. NCT02240706. https://clinicaltrials.gov/ct2/show/study/NCT02240706 (Accessed: August 2016).
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