mAb-based Therapeutics Research Articles

Characterization of monoclonal antibodies targeting SARS-CoV-2 spike glycoprotein: Reactivity against Delta and Omicron BA.1 variants

The cross-species transmissibility of SARS-CoV-2 infection has necessitated development of specific reagents for detecting infection in various animal species. The spike glycoprotein of SARS-CoV-2, which is involved in viral entry, is a highly immunogenic protein. To develop assays targeting this protein, we generated eight monoclonal antibodies (mAbs) against the S1 and seven against the S1/S2 protein (ectodomain) of SARS CoV-2. Based on neutralization capability and reactivity profile observed in ELISA, the mAbs generated against the S1/S2 antigen exhibited a broader spectrum of epitope specificity than those produced against the S1 domain alone. The full-length ectodomain induced antibodies that could neutralize the two most important variants of the virus encountered during the pandemic, namely Delta and Omicron. The availability of these reagents could greatly enhance the development of precise diagnostics for detecting COVID-19 infections in various host species and contribute to the advancement of mAb-based therapeutics.

In silico mediated workflow for rapid development of downstream processing: Orthogonal product-related impurity removal for a Fc-containing therapeutic

Therapeutic formats derived from the monoclonal antibody structure have been gaining significant traction in the biopharmaceutical market. Being structurally similar to mAbs, most Fc-containing therapeutics exhibit product-related impurities in the form of aggregates, charge variants, fragments, and glycoforms, which are inherently challenging to remove. In this work, we developed a workflow that employed rapid resin screening in conjunction with an in silico tool to identify and rank orthogonally selective processes for the removal of product-related impurities from a Fc-containing therapeutic product. Linear salt gradient screens were performed at various pH conditions on a set of ion-exchange, multimodal ion-exchange, and hydrophobic interaction resins. Select fractions from the screening experiments were analyzed by three different analytical techniques to characterize aggregates, charge variants, fragments, and glycoforms. The retention database generated by the resin screens and subsequent impurity characterization were then processed by an in silico tool that generated and ranked all possible two-step resin sequences for the removal of product-related impurities. A highly-ranked process was then evaluated and refined at the bench-scale to develop a completely flowthrough two-step polishing process which resulted in complete removal of the Man5 glycoform and aggregate impurities with a 73% overall yield. The successful implementation of the in silico mediated workflow suggests the possibility of a platformable workflow that could facilitate polishing process development for a wide variety of mAb-based therapeutics.

Abstract 5798: Preclinical safety assessment for specificity of biotherapeutics using the membrane proteome array

Abstract Rigorous specificity analysis is critical for the development of antibody-based therapies, as even minimal off-target binding can lead to toxicity and clinical failures. Long believed to be exquisitely specific, recent preclinical data and our own work indicate that monoclonal antibodies (MAbs) frequently (~25%) display cross-reactivity. In many cases, off-target interactions occur with unrelated proteins that cannot be predicted by protein sequence homology. Cross-reactivity can lead to serious or even life-threatening consequences especially when MAbs are configured as bispecifics, antibody-drug conjugates (ADC) or CAR-T cell therapies, and IND applications for biotherapeutics require cross-reactivity assessment to prevent adverse events. Tissue cross-reactivity (TCR) studies have traditionally been used to screen for off-target binding, however, with poor predictive value for in vivo safety and toxicity. We developed the Membrane Proteome Array (MPA) platform to de-risk MAb-based therapeutics by testing for specificity across 6,000 human membrane proteins expressed in unfixed cells. The MPA assesses binding interactions by high-throughput flow cytometry allowing for high sensitivity detection and rapid analysis. All targets identified on the MPA screen are validated by secondary titration analysis. In contrast to TCR studies, proteins in the MPA exist in their native conformations and are not altered by fixation. Recently, we used the MPA to select a lead antibody candidate targeting the oncotherapeutic target Claudin 6 (CLDN6). Through MPA screening, we successfully identified a lead candidate devoid of cross-reactivity against other CLDN family members or any other membrane protein across the human genome. The MPA has also been used to rapidly evaluate the specificity of novel CAR-T cell therapies for cancer and autoimmunity. The MPA has been used for lead selection and data from the MPA has been accepted by the FDA as a part of IND applications for antibody-based therapies. The MPA is currently under consideration for being developed as an FDA-qualified Drug Development Tool. Citation Format: Kristopher S. Raghavan, Jonathan T. Sullivan, Carmen Navia, Rachel H. Fong, Benjamin J. Doranz. Preclinical safety assessment for specificity of biotherapeutics using the membrane proteome array [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5798.

Abstract 2646: Screening the membrane proteome to determine antibody specificity and de-risk CAR-T cell development

Abstract Rigorous specificity analysis is critical for the development of antibody-based therapies, as even minimal off-target binding can lead to toxicity and clinical failures. Long believed to be exquisitely specific, recent preclinical data and our own work indicate that monoclonal antibodies (MAbs) frequently (~25%) display cross-reactivity. In many cases, off-target interactions occur with unrelated proteins that cannot be predicted by protein sequence homology. Cross-reactivity can lead to serious or even life-threatening consequences especially when MAbs are configured as bispecifics, antibody-drug conjugates (ADC) or CAR-T cell therapies, and IND applications for biotherapeutics require cross-reactivity assessment to prevent adverse events. Tissue cross-reactivity (TCR) studies have traditionally been used to screen for off-target binding, however, with poor predictive value for in vivo safety and toxicity. We developed the Membrane Proteome Array (MPA) platform to de-risk MAb-based therapeutics by testing for specificity across 6,000 human membrane proteins expressed in live cells. In contrast to TCR studies, proteins in the MPA exist in their native conformations and are not altered by fixation. The MPA assesses binding interactions by high-throughput flow cytometry allowing for high sensitivity detection and rapid analysis. We will discuss the importance of early-stage specificity testing to expose possible toxicities and present case studies for antibody and cell therapy profiling. MPA data have been used in numerous successful regulatory applications and may be used to replace or complement other cross-reactivity studies. In particular, MPA profiling has been used in IND applications for CAR-T and cell-therapies where conventional immunohistochemical binding assays did not suffice. Citation Format: Joseph Rucker, Rachel H. Fong, Tabb Sullivan, Carmen Navia, Brad Screnci, Rona Wilf, Benjamin J. Doranz. Screening the membrane proteome to determine antibody specificity and de-risk CAR-T cell development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2646.

Advancing humanized monoclonal antibody for counteracting fentanyl toxicity towards clinical development

ABSTRACT Innovative therapies to complement current treatments are needed to curb the growing incidence of fatal overdoses related to synthetic opioids. Murine and chimeric monoclonal antibodies (mAb) specific for fentanyl and its analogs have demonstrated pre-clinical efficacy in preventing and reversing drug-induced toxicity in rodent models. However, mAb-based therapeutics require extensive engineering as well as in vitro and in vivo characterization to advance to first-in-human clinical trials. Here, novel murine anti-fentanyl mAbs were selected for development based on affinity for fentanyl, and efficacy in counteracting the pharmacological effects of fentanyl in mice. Humanization and evaluation of mutations designed to eliminate predicted post-translational modifications resulted in two humanized mAbs that were effective at preventing fentanyl-induced pharmacological effects in rats. These humanized mAbs showed favorable biophysical properties with respect to aggregation and hydrophobicity by chromatography-based assays, and thermostability by dynamic scanning fluorimetry. These results collectively support that the humanized anti-fentanyl mAbs developed herein warrant further clinical development for treatment of fentanyl toxicity.

Complement-dependent phagocytosis as a regulator of antibody-dependent cellular cytotoxicity

Abstract While monoclonal antibodies (mAb), such as αCD20, have significantly improved patient outcomes for B cell malignancies, patient responses vary and drug resistance can occur. One proposed limitation is the reduction of innate immune effector functions such as antibody dependent cellular phagocytosis (ADCP) – the principal cytotoxic mechanism for many mAb-based therapeutics. ADCP is mediated by Fcγ Receptor- and complement-dependent pathways (FcγR-ADCP and cADCP, respectively). However, our lab has shown that the capacity of macrophages (Mϕ) to engulf mAb opsonized targets is finite and after brief period of engorgement, Mϕ enter a phase of negligible phagocytic activity termed hypophagia. We have previously described the mechanisms that negatively regulate FcγR-ADCP, but complement-induced hypophagia is less understood. To begin to characterize complement-induced exhaustion, we used live cell imaging to measure mAb opsonized thymocyte engulfment by primary mouse Mϕ in the presence absence of complement. Preliminary data suggest that cADCP kinetics and cytotoxic capacities are distinct from FcγR-ADCP; however, both lead to a hypophagic state that impinges on future target cell clearance. Furthermore, Mϕ refractory to additional FcγR-ADCP still phagocytose through complement receptors up until the cADCP pathway also becomes exhausted. Published data from our lab also show that FcγR driven hypophagia involves surface receptor downregulation, but interestingly, there is no reduction in complement receptor surface levels following cADCP-induced hypophagia. Therefore, a better understanding of cADCP and the mechanistic overlap with FcγR-ADCP is critical to optimizing mAb therapy by minimizing immune cell exhaustion. Supported by grants from NIH (T32 AI007496, 26A1)

Cyclodextrins as modulators for separation of charged variants of mAbs by capillary zone electrophoresis

Charge heterogeneity is a critical quality attribute for mAb-based therapeutics. Its characterization involves the identification of charge variant species in the final formulation. Capillary zone electrophoresis (CZE) is a valuable tool to assess charge heterogeneity, but typically offers incomplete separation of the different charged isoforms. Cyclodextrin-mediated chiral CE is a well-established electromigration method. In this paper, we propose the use of cyclodextrins as modulators for CZE based separation of mAb charge variants. Uncoated fused silica capillaries have been used for examining charge heterogeneity in biosimilars of Rituximab and Trastuzumab in presence of different cyclodextrins. Both the negatively charged CMβCD and uncharged HPβCD have been explored. The effect of cyclodextrin concentration has been found to impact the extent of modulation of resolution of charge variants. Addition of 10 mM CMβCD not only improved resolution but also resulted in separation of two additional basic and one additional acidic species for Rituximab. Similarly, besides improvement in the resolution of separation, one additional basic variant was observed with 2.5 mM CMβCD with another sample, Trastuzumab. The paper demonstrates that the effect of CMβCD is mAb specific. No improvement in resolution was, however, observed with HPβCD, suggesting the selective nature of cyclodextrins for mAb variants.

A Stable CHO K1 Cell Line for Producing Recombinant Monoclonal Antibody Against TNF-α.

Monoclonal antibodies (mAbs) are one of the most significant molecules in protein therapeutics. They are employed in the field of immunology, oncology and organ transplant. They have been also been employed for alleviating several bacterial and viral infections. Moreover, they have revolutionized the area of targeted therapy and improved the quality of treatments, as compared to other cytotoxic drugs and therapies. mAbs bind to specific molecules on the antigen and exhibit specificity towards that molecule, i.e. epitope. Thus, mAbs have immense opportunity to be explored for personalized therapy. The introduction of targeted mAb-based therapeutics has promoted many important scientific achievements in rheumatology. This has warranted additional investigations for developing newer mAb producing clones, to supplement the limited industrial production of certain mAb therapeutics. In this investigation, an integrative approach comprising optimized expression, selection and expansion was adopted to develop a mammalian cell line expressing mAb against TNF-α.The resulting stable clone is anticipated to serve as an economic alternative to the industrial clones, especially for research purposes. The clone was constructed for development of biosimilar of the highly valued therapeutic antibody, Humira.

The Current Landscape of Antibody-based Therapies in Solid Malignancies.

Over the past three decades, monoclonal antibodies (mAbs) have revolutionized the landscape of cancer therapy. Still, this benefit remains restricted to a small proportion of patients due to moderate response rates and resistance emergence. The field has started to embrace better mAb-based formats with advancements in molecular and protein engineering technologies. The development of a therapeutic mAb with long-lasting clinical impact demands a prodigious understanding of target antigen, effective mechanism of action, gene engineering technologies, complex interplay between tumor and host immune system, and biomarkers for prediction of clinical response. This review discusses the various approaches used by mAbs for tumor targeting and mechanisms of therapeutic resistance that is not only caused by the heterogeneity of tumor antigen, but also the resistance imposed by tumor microenvironment (TME), including inefficient delivery to the tumor, alteration of effector functions in the TME, and Fc-gamma receptor expression diversity and polymorphism. Further, this article provides a perspective on potential strategies to overcome these barriers and how diagnostic and prognostic biomarkers are being used in predicting response to mAb-based therapies. Overall, understanding these interdependent parameters can improve the current mAb-based formulations and develop novel mAb-based therapeutics for achieving durable clinical outcomes in a large subset of patients.

AAV Vectored Immunoprophylaxis for Filovirus Infections.

Filoviruses are among the deadliest infectious agents known to man, causing severe hemorrhagic fever, with up to 90% fatality rates. The 2014 Ebola outbreak in West Africa resulted in over 28,000 infections, demonstrating the large-scale human health and economic impact generated by filoviruses. Zaire ebolavirus is responsible for the greatest number of deaths to date and consequently there is now an approved vaccine, Ervebo, while other filovirus species have similar epidemic potential and remain without effective vaccines. Recent clinical success of REGN-EB3 and mAb-114 monoclonal antibody (mAb)-based therapies supports further investigation of this treatment approach for other filoviruses. While efficacious, protection from passive mAb therapies is short-lived, requiring repeat dosing to maintain therapeutic concentrations. An alternative strategy is vectored immunoprophylaxis (VIP), which utilizes an adeno-associated virus (AAV) vector to generate sustained expression of selected mAbs directly in vivo. This approach takes advantage of validated mAb development and enables vectorization of the top candidates to provide long-term immunity. In this review, we summarize the history of filovirus outbreaks, mAb-based therapeutics, and highlight promising AAV vectorized approaches to providing immunity against filoviruses where vaccines are not yet available.

IgA as a potential candidate for enteric monoclonal antibody therapeutics with improved gastrointestinal stability

Mucosal surfaces of the gastrointestinal tract play an important role in immune homeostasis and defense and may be compromised by enteric disorders or infection. Therapeutic intervention using monoclonal antibody (mAb) offers the potential for treatment with minimal off-target effects as well as the possibility of limited systemic exposure when administered orally. Critically, to achieve efficacy at luminal surfaces, mAb must remain stable and functionally active in the gastrointestinal environment. To better understand the impact of isotype, class, and molecular structure on the intestinal stability of recombinant antibodies, we used an in vitro simulated intestinal fluid (SIF) assay to evaluate a panel of antibody candidates for enteric mAb-based therapeutics. Recombinant IgG1 was the least stable following SIF incubation, while the stability of IgA generally increased upon polymerization, with subtle differences between subclasses. Notably, patterns of variability within and between mAbs suggest that variable regions contribute to mAb stability and potentially mediate mAb susceptibility to proteases. Despite relatively rapid degradation in SIF, mAbs targeting Enterotoxigenic Escherichia coli (ETEC) displayed functional activity following SIF treatment, with SIgA1 showing improved function compared to SIgA2. The results of this study have implications for the design of enteric therapeutics and subsequent selection of lead candidates based upon in vitro intestinal stability assessments.

Critical role of EphA3 in cancer and current state of EphA3 drug therapeutics.

The erythropoietin-producing human hepatocellular (Eph) receptors are transmembrane glycoprotein members of the tyrosine kinase receptors family. The Ephs may bind to various ephrin ligands resulting in the phosphorylation of their tyrosine kinase domain and the activation of the Eph receptor. In this review we focus on EphA3, one receptor of the 14 different Ephs, as it carries out both redundant and restricted functions in the germline development of mammals and in the maintenance of various adult tissues. The loss of EphA3 regulation is correlated with various human malignancies, the most notable being cancer. This receptor is overexpressed and/or mutated in multiple tumors, and is also associated with poor prognosis and decreased survival in patients. Here we highlight the role of EphA3 in normal and malignant tissues that are specific to cancer; these include hematologic disorders, gastric cancer, glioblastoma multiforme, colorectal cancer, lung cancer, renal cell carcinoma, and prostate cancer. Moreover, various anticancer agents against EphA3 have been developed to either inhibit its kinase domain activity or to function as agonists. Thus, we examine the most potent small molecule drugs and mAb-based therapeutics against EphA3 that are currently in pre-clinical or clinical stages.

Pharmacokinetics of Human Recombinant Anti-Botulinum Toxin Antibodies in Rats.

Botulinum neurotoxins (BoNT) are potential biothreat agents due to their high lethality, potency, and ease of distribution, thus the development of antitoxins is a high priority to the US government. This study examined pre-clinical pharmacokinetic studies in rats of four oligoclonal anti-BoNT mAb-based therapeutics (NTM-1631, NTM-1632, NTM-1633, NTM-1634) for five BoNT serotypes (A, B, E, C, and D). NTM-1631, NTM-1632, and NTM-1633 each consist of three IgG1 mAbs, each with a distinct human or humanized variable region which bind to distinct epitopes on BoNT serotype A, B, or E respectively. NTM-1634 consists of four human immunoglobulin G1 (IgG1) mAbs binding BoNT C/D mosaic toxins. The mechanism of these antitoxins requires that three antibodies simultaneously bind toxin to achieve rapid clearance. Rats (total 378) displayed no adverse clinical signs attributed to antibody treatment from any of the antitoxins. Pharmacokinetic evaluation demonstrated that the individual mAbs are slowly eliminated, exhibiting dose-dependent exposure and long elimination half-lives ranging from 6.5 days to 10 days. There were no consistent differences observed between males and females or among the individual antibodies in each formulation in half-life. Anti-drug antibodies (ADA) were observed, as expected for human antibodies administered to rats. The results presented were used to support the clinical investigation of antibody-based botulism antitoxins.

Targeting the human MUC1-C oncoprotein with an antibody-drug conjugate.

Mucin 1 (MUC1) is a heterodimeric protein that is aberrantly overexpressed on the surface of diverse human carcinomas and is an attractive target for the development of mAb-based therapeutics. However, attempts at targeting the shed MUC1 N-terminal subunit have been unsuccessful. We report here the generation of mAb 3D1 against the nonshed oncogenic MUC1 C-terminal (MUC1-C) subunit. We show that mAb 3D1 binds with low nM affinity to the MUC1-C extracellular domain at the restricted α3 helix. mAb 3D1 reactivity is selective for MUC1-C-expressing human cancer cell lines and primary cancer cells. Internalization of mAb 3D1 into cancer cells further supported the conjugation of mAb 3D1 to monomethyl auristatin E (MMAE). The mAb 3D1-MMAE antibody-drug conjugate (ADC) (a) kills MUC1-C-positive cells in vitro, (b) is nontoxic in MUC1-transgenic (MUC1.Tg) mice, and (c) is active against human HCC827 lung tumor xenografts. Humanized mAb (humAb) 3D1 conjugated to MMAE also exhibited antitumor activity in (a) MUC1.Tg mice harboring syngeneic MC-38/MUC1 tumors, (b) nude mice bearing human ZR-75-1 breast tumors, and (c) NCG mice engrafted with a patient-derived triple-negative breast cancer. These findings and the absence of associated toxicities support clinical development of humAb 3D1-MMAE ADCs as a therapeutic for the many cancers with MUC1-C overexpression.

Targeting Human β-Microglobulin with Monoclonal Antibodies in Multiple Myeloma - A Potential in Treatment

Multiple myeloma (MM) is a clonal plasma cell neoplasm that utilizes bone marrow microenvironment for survival and proliferation [1-3]. However, current therapies could rarely cure MM. The relapse or refractory aspect of the disease is commonly seen in MM patients, especially among patients with high-risk MM. In past decades, targeted immunotherapy with monoclonal antibodies (mAbs) emerged as a major new treatment modality that offered great benefits for MM patients [4]. Different approaches, aimed at finding potential mAbbased therapeutics for this disease including identification of alternative, or novel, target antigens [5], conjugation of mAbs with classic or novel drugs [6], and generation of chimeric antigen receptor T cells with specific mAbs [7], have been developed by scientists. Recently, our group has generated the mAbs that work directly against human β2-microglobulin (β2M) both in vitro and in the mouse experiments, and has demonstrated that β2M is a potential target for MM treatment [8].

Attenuation of Staphylococcus aureus-Induced Bacteremia by Human Mini-Antibodies Targeting the Complement Inhibitory Protein Efb.

Staphylococcus aureus can cause a broad range of potentially fatal inflammatory complications (e.g., sepsis and endocarditis). Its emerging antibiotic resistance and formidable immune evasion arsenal have emphasized the need for more effective antimicrobial approaches. Complement is an innate immune sensor that rapidly responds to bacterial infection eliciting C3-mediated opsonophagocytic and immunomodulatory responses. Extracellular fibrinogen-binding protein (Efb) is a key immune evasion protein of S. aureus that intercepts complement at the level of C3. To date, Efb has not been explored as a target for mAb-based antimicrobial therapeutics. In this study, we have isolated donor-derived anti-Efb IgGs that attenuate S. aureus survival through enhanced neutrophil killing. A phage library screen yielded mini-Abs that selectively inhibit the interaction of Efb with C3 partly by disrupting contacts essential for complex formation. Surface plasmon resonance-based kinetic analysis enabled the selection of mini-Abs with favorable Efb-binding profiles as therapeutic leads. Mini-Ab-mediated blockade of Efb attenuated S. aureus survival in a whole blood model of bacteremia. This neutralizing effect was associated with enhanced neutrophil-mediated killing of S. aureus, increased C5a release, and modulation of IL-6 secretion. Finally, these mini-Abs afforded protection from S. aureus-induced bacteremia in a murine renal abscess model, attenuating bacterial inflammation in kidneys. Overall, these findings are anticipated to pave the way toward novel Ab-based therapeutics for S. aureus-related diseases.

Abstract 1277: Tumor-specific human monoclonal antibodies isolated from cancer patients that bind antigens expressed on the outer plasma membrane of cancer cells

Abstract Introduction: Cancer cells express novel antigens that reflect their transformed state and may engender an antibody response. We hypothesize that some of these auto-antibodies detect neo-antigens that are shared by diverse tumor types and that a subset of these are expressed on the outer plasma membrane (PM) of cancer cells, but not normal cells. Here, we describe two human mAbs, isolated from lymph node B-cells of breast cancer patients, that bind antigens expressed only on the surface of cancer cells. Methods: We have optimized a hybridoma method for cloning human IgG monoclonal antibodies (mAbs) by screening for those that bind to live, heterologous cancer cell lines. We use whole cell immunofluorescence binding assays with human cancer cell lines, detecting cell-reactive human IgG with the Operetta. We use B-cells from lymph nodes obtained at surgery from stage I, ER+PR+ breast cancer patients and Stage I or II lung cancer patients, as well as peripheral blood B-cells from lung cancer patients responsive to PD-1 inhibitors. We used cDNA library expression methods to identify the tumor antigens and characterized the tumor-specific activities of two mAbs using immunohistochemistry (IHC), gene transfection, flow cytometry, immunoblotting, and invasion assays. Results: Two of the mAbs isolated from lymph nodes of patients with breast cancer bind to antigens that are only expressed on the outer PM of cancer cells. The antigen recognized by mAb 9H2 is known to be expressed on the outer PM of metastatic cells, while the antigen recognized by mAb 2B9 is a cytoplasmic protein not previously recognized to exist on the outer PM. IHC demonstrates that the 9H2 antigen is expressed only rarely on normal cells, but is commonly on breast and colon cancers (3 of 4 samples tested for each tumor type). Binding was also seen on 2 of 4 small cell lung cancers samples and 1 of 3 pancreatic cancers. The existence of the 2B9 antigen on the outer PM was confirmed by study of 293T cells transiently transfected with MYC-tagged antigen expression constructs and analyzed by flow cytometry with the mAb 2B9 and an anti-myc mAb. Treatment of MDA-MB-231 cells with the mAb 2B9 substantially reduced invasion in the transwell migration assay. An additional panel of 12 mAbs exhibited internalizing activity and is being evaluated for efficacy as antibody-drug conjugates Conclusion: Our panel of mAbs from cancer patients supports the hypothesis that patients with malignancies make antibodies that bind novel cancer-specific antigens. Two mAbs bind antigens expressed only on the surface of malignant cells; one has not previously been detected on the outer PM. The ability of mAb 2B9 to inhibit breast cancer cell invasion suggests that the anti-tumor immune response may be functional. Studying the anti-cancer antibody repertoire may identify new targets for mAb-based cancer diagnostics and therapeutics. Citation Format: Baron Heimbach, Cezary Swider, Huiwu Zhao, Paul Simon, R. Katherine Alpaugh, Michael Walker, David Krag, David Knight, Tung Chan, Hossein Borghaei, Scott Dessain. Tumor-specific human monoclonal antibodies isolated from cancer patients that bind antigens expressed on the outer plasma membrane of cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1277. doi:10.1158/1538-7445.AM2015-1277

Building better monoclonal antibody-based therapeutics.

For 20 years, monoclonal antibodies (mAbs) have been a standard component of cancer therapy, but there is still much room for improvement. Efforts continue to build better cancer therapeutics based on mAbs. Anticancer mAbs function through various mechanisms, including directly targeting the malignant cells, modifying the host response, delivering cytotoxic moieties and retargeting cellular immunity towards the malignant cells. Characteristics of mAbs that affect their efficacy include antigen specificity, overall structure, affinity for the target antigen and how a mAb component is incorporated into a construct that can trigger target cell death. This Review discusses the various approaches to using mAb-based therapeutics to treat cancer and the strategies used to take advantage of the unique potential of each approach, and provides examples of current mAb-based treatments.

In silico selection of therapeutic antibodies for development: viscosity, clearance, and chemical stability.

For mAbs to be viable therapeutics, they must be formulated to have low viscosity, be chemically stable, and have normal in vivo clearance rates. We explored these properties by observing correlations of up to 60 different antibodies of the IgG1 isotype. Unexpectedly, we observe significant correlations with simple physical properties obtainable from antibody sequences and by molecular dynamics simulations of individual antibody molecules. mAbs viscosities increase strongly with hydrophobicity and charge dipole distribution and decrease with net charge. Fast clearance correlates with high hydrophobicities of certain complementarity determining regions and with high positive or high negative net charge. Chemical degradation from tryptophan oxidation correlates with the average solvent exposure time of tryptophan residues. Aspartic acid isomerization rates can be predicted from solvent exposure and flexibility as determined by molecular dynamics simulations. These studies should aid in more rapid screening and selection of mAb candidates during early discovery.

Network biology in development of monoclonal antibody therapeutics

Monoclonal antibodies (mAbs) are large glycoproteins that recognize and remove/neutralize a specific target. Inflammation and inflammatory diseases are often treated with mAb-based therapeutics. Mathematical modeling is widely used in development of mAbs. Bioinformatics and structural modeling is used for humanization of mAbs and PK/PD modeling is extensively used in preclinical and clinical development. The objective of this commentary is to introduce systems biology-based modeling that can accelerate and improve development of mAbs.