Balancing Selectivity and Efficacy of Bispecific Epidermal Growth Factor Receptor (EGFR) × c-MET Antibodies and Antibody-Drug Conjugates

Abstract

Bispecific antibodies (bsAbs) and antibody-drug conjugates (ADCs) have already demonstrated benefits for the treatment of cancer in several clinical studies, showing improved drug selectivity and efficacy. In particular, simultaneous targeting of prominent cancer antigens, such as EGF receptor (EGFR) and c-MET, by bsAbs has raised increasing interest for potentially circumventing receptor cross-talk and c-MET-mediated acquired resistance during anti-EGFR monotherapy. In this study, we combined the selectivity of EGFR × c-MET bsAbs with the potency of cytotoxic agents via bispecific antibody-toxin conjugation. Affinity-attenuated bispecific EGFR × c-MET antibody-drug conjugates demonstrated high in vitro selectivity toward tumor cells overexpressing both antigens and potent anti-tumor efficacy. Due to basal EGFR expression in the skin, ADCs targeting EGFR in general warrant early safety assessments. Reduction in EGFR affinity led to decreased toxicity in keratinocytes. Thus, the combination of bsAb affinity engineering with the concept of toxin conjugation may be a viable route to improve the safety profile of ADCs targeting ubiquitously expressed antigens.

Intein mediated high throughput screening for bispecific antibodies

“…As expected, c-METxEGFR bispecifics B10v5xhu225L and B10v5xhu225H showed similar binding kinetics for B10v5 against c-MET (0.8 nM), matching data previously described (S16A, B). [13] Simultaneous binding to c-MET and EGFR was confirmed by stepwise association of both antigens to B10v5xhu225H via BLI analysis and monospecific B10v5 oaSEED was used to investigate unspecific binding to EGFR (Figure S16 C). Cellular binding to expressed antigens c-MET and EGFR on the cell surface of several cancer cell lines was confirmed by flow cytometry (Figure S17).…”

“…The ability to simultaneously bind two different epitopes enables a variety of potential modes of actions, such as an improved cytotoxic potential by bridging cells in-trans, synergistic effects, receptor crosslinking for enhanced inhibition or degradation and higher binding specificity, resulting, for example, in enhanced tumor selectivity. [10][11][12][13] Tackling a cancer disease often requires inhibition of more than one signaling pathway. Often, combination therapies or bsAbs can help to overcome the limitations of ordinary monoclonal antibodies (mAbs) restricted to only one epitope.…”

Nanoscale integration of single cell biologics discovery processes using optofluidic manipulation and monitoring

“…The development of large molecule therapeutics with optimal potency, selectivity, and biophysical properties often requires the generation and screening of many engineered antibody variants (Chiu & Gilliland, ). Depending on the properties desired in the final molecule, these engineering designs may target affinity or selectivity modulation (Kiyoshi et al, ; Sellmann et al, ; Tiller et al, ), reduction in immunogenicity (Presta, ), better pharmacokinetics (Haraya, Tachibana, & Igawa, ; Hotzel et al, ), removal of chemically labile sites (Chelius, Rehder, & Bondarenko, ; DiCara et al, ; Haberger et al, ), and/or improvement in other biophysical properties related to manufacturing (Jarasch et al, ; Seeliger et al, ; Xu et al, ). Standard methods of screening panels of molecules that have been engineered for multi‐parameter optimization require cloning, expression, and purification of a sufficient quantity of protein to run multiple assays.…”

Induction of potent apoptosis by an anti-CD20 aptamer via the crosslink of membrane CD20 on non-Hodgkin's lymphoma cells

“…5 Besides, toxic substances, such as radioisotopes or cytotoxic agents, can be accurately delivered to malignant cells with the guiding of certain mAbs by the construction of antibody-drug conjugates (ADCs). 6,7 CD20 is a B-cell differentiating antigen, which selectively expressed on the surface of mature and malignant B-cells. 8 Currently, 5 anti-CD20 mAbs have been approved by the U.S. FDA (Food and Drug Administration): Rituximab (RTX, Rituxan), Ofatumumab (Arzerra), Obinutuzumab (Gazyva), the radio-conjugates Bexxar (Tositumomab-I 131 ) and Zevalin (Ibritumomab tiuxetan).…”

“…22 (5) Aptamers are synthesized consistently and with great accuracy every time, while antibodies can vary batch by batch, and require routine performance validation. 25 (6) Unlike antibodies which can only be generated to antigens with immuno-stimulatory capacities, aptamers can be raised to virtually any targets including ions, small molecules, proteins, virus and even whole cells. [26][27][28] However, no therapeutic aptamer or aptamer derivative targeting CD20 has been developed for treating B cell malignancies.…”