Glycovariant anti-CD37 monospecific protein therapeutic exhibits enhanced effector cell-mediated cytotoxicity against chronic and acute B cell malignancies

S Rafiq, A Siadak, JP Butchar, C Cheney, G Lozanski… - MAbs, 2013 - Taylor & Francis
S Rafiq, A Siadak, JP Butchar, C Cheney, G Lozanski, NK Jacob, R Lapalombella…
MAbs, 2013Taylor & Francis
TRU-016 is a SMIPTM (monospecific protein therapeutic) molecule against the tetraspanin
transmembrane family protein CD37 that is currently in Phase 2 trials in Chronic
Lymphocytic Leukemia (CLL) and Non-Hodgkin Lymphoma (NHL). In an attempt to enhance
the ADCC function of SMIP-016, the chimeric version of TRU-016, SMIP-016GV was
engineered with a modification in a glycosylation site in the Fc domain. The wild-type and
glycovariant SMIP proteins mediate comparable Type I antibody-like direct cytotoxicity in the …
TRU-016 is a SMIPTM (monospecific protein therapeutic) molecule against the tetraspanin transmembrane family protein CD37 that is currently in Phase 2 trials in Chronic Lymphocytic Leukemia (CLL) and Non-Hodgkin Lymphoma (NHL). In an attempt to enhance the ADCC function of SMIP-016, the chimeric version of TRU-016, SMIP-016GV was engineered with a modification in a glycosylation site in the Fc domain. The wild-type and glycovariant SMIP proteins mediate comparable Type I antibody-like direct cytotoxicity in the presence of anti-human Fc crosslinker and show a similar tyrosine phosphorylation pattern post-treatment. However, NK cells stimulated with the SMIP-016GV exhibit enhanced activation and release 3-fold more interferon-γ compared with SMIP-016. SMIP-016GV shows enhanced ADCC function against cells expressing CD37 with NK cell effectors derived from both normal and CLL-affected individuals. Enhanced ADCC is observed against CLL cells and is sustained at concentrations of SMIP-016GV as low at 5E−6 µg/mL on cells expressing minimal CD37 antigen. In support of the biological relevance of this, SMIP-016GV mediates effective ADCC against primary acute lymphoblastic leukemia (ALL) cells with low surface expression of CD37. Collectively, these data suggest potential use of the novel therapeutic agent SMIP-016GV with enhanced effector function for B cell malignancies, including CLL and ALL therapy.
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