Engineered anti-CD70 antibody-drug conjugate with increased therapeutic index

Abstract

An anti-CD70 antibody conjugated to monomethylauristatin F (MMAF) via a valine-citrulline dipeptide containing linker has been shown previously to have potent antitumor activity in renal cell cancer xenograft studies. Here, we generated a panel of humanized anti-CD70 antibody IgG variants and conjugated them to MMAF to study the effect of isotype (IgG1, IgG2, and IgG4) and Fc; receptor binding on antibody-drug conjugate properties. All IgG variants bound CD70 + 786-O cells with an apparent affinity of f1 nmol/L, and drug conjugation did not impair antigen binding. The parent anti-CD70 IgG1 bound to human Fc;RI and Fc;RIIIA V158 and mouse Fc;RIV and this binding was not impaired by drug conjugation. In contrast, binding to these Fc; receptors was greatly reduced or abolished in the variant, IgG1v1, containing the previously described mutations, E233P:L234V:L235A. All conjugates had potent cytotoxic activity against six different antigen-positive cancer cell lines in vitro with IC 50 values of 30 to 540 pmol/L. The IgGv1 conjugate with MMAF displayed improved antitumor activity compared with other conjugates in 786-O and UMRC3 models of renal cell cancer and in the DBTRG05-MG glioblastoma model. All conjugates were tolerated to z40 mg/kg in mice. Thus, the IgG1v1 MMAF conjugate has an increased therapeutic index compared with the parent IgG1 conjugate. The improved antitumor activity of the IgG1v1 auristatin conjugates may relate to increased exposure as suggested by pharmacokinetic analysis. The strategy used here for enhancing the therapeutic index of antibody-drug conjugates is independent of the antigen-binding variable domains and potentially applicable to other antibodies.

Novel anti–B-cell maturation antigen antibody-drug conjugate (GSK2857916) selectively induces killing of multiple myeloma

“…These data are consistent with previously published studies with the other mcMMAF ADC targeting CD70. 30,31,[33][34][35] Both ADCs induced apoptosis of CD138 1 patient MM cells following 3 days' treatment, and greater dose-dependent killing was seen by J6M0-mcMMAF than J6M0-vcMMAE ( Figure 2C). Percentages of annexin V/propidium iodide (PI) cells combined were 45.8% 6 0.5% and 74.5% 6 1.2% at 0.01 mg/mL and 1 mg/mL J6M0-mcMMAF, respectively.…”

“…These data are consistent with previously published studies with the other mcMMAF ADC targeting CD70. 30,31,[33][34][35] Both ADCs induced apoptosis of CD138…”

5-Azacytidine enhances the anti-leukemic activity of lintuzumab (SGN-33) in preclinical models of acute myeloid leukemia

“…First, a variant of lintuzumab (SGN-33 G1v1) with amino acid substitutions in the heavy chain constant domains to reduce Fcg receptor binding was engineered. 35 Similar to a G1v1 variant of an anti-CD70 antibody, 36 SGN-33 G1v1 does not bind to the human Fcg receptor I (CD64), Fcg receptor IIIA (CD16), or to the murine Fcg receptor IV (the functional counterpart of CD16) (data not shown). The G1v1 engineering of SGN-33 completely abolished the anti-leukemic activity of the antibody (Fig.…”

Antibody–drug conjugates: targeted weapons against cancer

“…However, contrasting evidence exists: no differences in ADC function depending on the format have been demonstrated so far. 98 Nonetheless, a systematic analysis has not yet been performed. A recent advance in this perspective has come from the POTELLIGENT technology (BioWa, Inc., Princeton, NJ, USA), which consists in the elimination of fucose from sugar chains of antibodies, determining a significant increase in antibody-dependent cell-mediated cytotoxicity and, consequently, in the efficacy of the ADC.…”