Engineered antibody Fc variants with enhanced effector function

Abstract

Antibody-dependent cell-mediated cytotoxicity, a key effector function for the clinical efficacy of monoclonal antibodies, is mediated primarily through a set of closely related Fc␥ receptors with both activating and inhibitory activities. By using computational design algorithms and high-throughput screening, we have engineered a series of Fc variants with optimized Fc␥ receptor affinity and specificity. The designed variants display >2 orders of magnitude enhancement of in vitro effector function, enable efficacy against cells expressing low levels of target antigen, and result in increased cytotoxicity in an in vivo preclinical model. Our engineered Fc regions offer a means for improving the next generation of therapeutic antibodies and have the potential to broaden the diversity of antigens that can be targeted for antibody-based tumor therapy.antibody-dependent cell-mediated cytotoxicity ͉ Fc␥R ͉ protein engineering ͉ cancer

The “less-is-more” in therapeutic antibodies: Afucosylated anti-cancer antibodies with enhanced antibody-dependent cellular cytotoxicity

“…These Fc variants of either single (S239D or I332E), double (S239D/I332E) or triple (S239D/I332E/A330L) mutations demonstrated up to 169-fold enhanced interaction with human FcγRIIIa 71 . The Fc variants also showed enhanced binding ratio between activating FcRγIIIa and inhibitory FcγRIIb of up to 9-fold.…”

“…With the use of computational structure-based design and high-throughput screening, a series of engineered Fc variants were generated 71 . These Fc variants of either single (S239D or I332E), double (S239D/I332E) or triple (S239D/I332E/A330L) mutations demonstrated up to 169-fold enhanced interaction with human FcγRIIIa 71 .…”

Generation, selection and preclinical characterization of an Fc-optimized FLT3 antibody for the treatment of myeloid leukemia

“…By defined genetic engineering of the glycosylation pattern or the amino-acid sequence of the Fc part, antibody variants with markedly improved ADCC activity have been generated. 3,4 Different companies use different strategies: Roche (Basel, Switzerland), in cooperation with Glycart (Schlieren, Switzerland), has developed an improved, glyco-engineered CD20 antibody, termed GA101. 5 Two other antibodies directed to the lymphoma-associated antigens CD19 (XmAb5574) 6,7 and CD30 (XmAb2513), 8 developed by Xencor (Monrovia, CA, USA), carry the amino-acid exchanges S239D and I332E (SDIE modification).…”

Receptor occupancy assessment by flow cytometry as a pharmacodynamic biomarker in biopharmaceutical development

“…A fluorescence‐labeled, non‐neutralizing anti‐idiotypic antibody or an antibody with specificity for Fc 2, 3, 22 or a modified Fc region 38, 39, 40 can be used for detection. Selection of specific, high affinity reagents is essential for robust detection sensitivity.…”