DNA-delivered monoclonal antibodies targeting the p53 R175H mutant epitope inhibit tumor development in mice

The tumor suppressor p53 is the most common mutated gene in cancer, with the R175H as the most frequent p53 missense mutant. However, there are currently no approved targeted therapies or immunotherapies against mutant p53. Here, we characterized and investigated a monoclonal antibody (mAb) that recognizes the mutant p53-R175H for its affinity, specificity, and activity against tumor cells in vitro. We then delivered DNA plasmids expressing the anti-R175H mAb or a bispecific antibody (BsAb) into mice to evaluate their therapeutic effects. Our results showed that the anti-R175H mAb specifically bound to the p53-R175H antigen with a high affinity and recognized the human mutant p53-R175H antigen expressed on HEK293T or MC38 cells, with no cross-reactivity with wild-type p53. In cultured cells, the anti-R175H mAb showed higher cytotoxicity than the control but did not induce antibody-dependent cellular cytotoxicity. We made a recombinant MC38 mouse cell line (MC38-p53-R175H) that overexpressed the human p53-R175H after knocking out the endogenous mutant p53 alleles. In vivo, administration of the anti-R175H mAb plasmid elicited a robust anti-tumor effect against MC38-p53-R175H in mice. The administration of the anti-R175H BsAb plasmid showed no therapeutic effects, yet potent anti-tumor activity was observed in combination with the anti-PD-1 antibody. These results indicate that targeting specific mutant epitopes using DNA-delivered mAbs or BsAbs presents a form of improved natural immunity derived from tumor-infiltrating B cells and plasma cells against intracellular tumor antigens.

Novel purification platform based on multimodal preparative scale separation of mAb fragments and aggregates

Monoclonal antibodies (mAbs) continue to dominate the biopharmaceutical industry. Certain mAbs are prone to fragmentation and clipping and in these cases, adequate removal of these species is critical during manufacturing. Fragments can be generated during fermentation, purification, storage, formulation, and administration. Their addition to the acidic charge-variant of the purified mAb has been reported to decrease stability and potency of the final product. However, contrary to mAb aggregation, manufacturers have not given much attention to removal of fragments and clipped species and as a result most conventional mAb platforms offer at best limited capabilities for their removal. In this study, we propose a novel purification platform that uses multimodal chromatography and achieves complete removal of a range of mAb fragments and clipped products (25-120 kDa). The utility of the platform has been successfully demonstrated for 2 IgG1s and 2 IgG4s. Further, adequate removal of the various host cell impurities such as host cell proteins (<10 ppm) and host cell DNA (<5 ppb) has been achieved. Finally, the platform was able to deliver adequate removal of high molecular weight impurities (<1 %) and a 30 % clearance of the acidic charge variant. The proposed single step has been shown to deliver what the polishing chromatography and intermediate purification chromatography steps deliver in a traditional mAb platform.

Facile generation of biepitopic antibodies with intrinsic agonism for activating tumor necrosis factor receptors

Agonist antibodies are being pursued for therapeutic applications ranging from neurodegenerative diseases to cancer. For the tumor necrosis factor (TNF) receptor superfamily, higher-order clustering of three or more receptors is key to their activation, which can be achieved using antibodies that recognize two unique epitopes. However, the generation of biepitopic (i.e., biparatopic) antibodies typically requires animal immunization and is laborious and unpredictable. Here, we report a simple method for identifying biepitopic antibodies that potently activate TNF receptors without the need for additional animal immunization. Our approach uses existing, receptor-specific IgGs, which lack intrinsic agonist activity, to block their corresponding epitopes, then selects single-chain antibodies that bind accessible epitopes. The selected antibodies are fused to the light chains of IgGs to generate human tetravalent antibodies. We highlight the broad utility of this approach by converting several clinical-stage antibodies against OX40 and CD137 (4-1BB) into biepitopic antibodies with potent agonist activity.

A new era of immune therapeutics for pancreatic cancer: Monoclonal antibodies paving the way

Pancreatic cancer, particularly pancreatic ductal adenocarcinoma, remains a devastating disease with a dismal prognosis and limited survival rates. Despite various drug treatments and regimens showing promise in managing the disease, the clinical outcomes have not significantly improved. Immunotherapy however, has become a forefront area in pancreatic cancer treatment. This approach comprises a range of agents, including small molecule drugs, antibodies, combination therapies, and vaccines. In the last 5-8 years, there has been an upsurge of research into the use of monoclonal antibodies to block receptors on cancer or immune cells, revolutionising cancer treatment and management. Several targets have been identified and studied, with the most encouraging noted in relation to checkpoint markers, namely, antibodies targeting anti-programmed cell death 1 (PD-1) and its receptor PD-L1. Herein, we present the clinical developments in immunotherapy in the last 5 years especially those which have been tested in humans against pancreatic cancer.

A targetable receptor-binding site on PfCyRPA to aid in the fight against malaria

Recently, Day et al. identified a receptor-binding site on the malaria parasite protein PfCyRPA that binds the host sugar Neu5Ac, and they found that disrupting this interaction impedes parasite growth. A map of the receptor-binding site identifies an attractive target for antimalarial vaccines and therapeutics.

SEC-HPLC analysis of column load and flow-through provides critical understanding of low Protein A step yield

For a certain number of mAbs, bispecific antibodies (bsAbs) and Fc-fusion proteins that we worked on, the Protein A capture step experienced low yield (i.e., ∼80%). A previous case study suggested that non-binding aggregate formed in cell culture was the root cause of low Protein A step yield. In the current work, we selected five projects with the low Protein A yield issue to further illustrate this phenomenon. In all cases, existence of non-binding aggregates was confirmed by size-exclusion chromatography-high performance liquid chromatography (SEC-HPLC) analysis of Protein A load and flow-through. In addition, we demonstrated that aggregates failed to bind to Protein A resin mainly due to their large sizes, which prevented them from entering the resin beads. As the data suggested, SEC-HPLC analysis of Protein A load and flow-through, although not a standard procedure, can provide information that is critical for understanding the unexpected performance of Protein A chromatography in cases like those being presented here. Thus, SEC-HPLC analysis of Protein A load and flow-through is highly recommended for antibodies/Fc-fusions suffering from low Protein A yield.

Protective human monoclonal antibodies target conserved sites of vulnerability on the underside of influenza virus neuraminidase

Continuously evolving influenza viruses cause seasonal epidemics and pose global pandemic threats. Although viral neuraminidase (NA) is an effective drug and vaccine target, our understanding of the NA antigenic landscape still remains incomplete. Here, we describe NA-specific human antibodies that target the underside of the NA globular head domain, inhibit viral propagation of a wide range of human H3N2, swine-origin variant H3N2, and H2N2 viruses, and confer both pre- and post-exposure protection against lethal H3N2 infection in mice. Cryo-EM structures of two such antibodies in complex with NA reveal non-overlapping epitopes covering the underside of the NA head. These sites are highly conserved among N2 NAs yet inaccessible unless the NA head tilts or dissociates. Our findings help guide the development of effective countermeasures against ever-changing influenza viruses by identifying hidden conserved sites of vulnerability on the NA underside.

Strategy and validation of a nonclinical generic plug-and-play antidrug antibody method for human monoclonal antibody biotherapeutics

The measurement of antidrug antibodies (ADA) in nonclinical studies provides limited value because the formation and incidence of nonclinical ADA does not translate to clinical experience. The formation and presence of ADA in nonclinical species can, however, correlate to reduced drug exposure and safety observations including vasculitis and immune complex disease. Generic ADA methods for humanized monoclonal antibody biotherapeutics mitigate the need to develop bespoke ADA methods during nonclinical drug development. A drug-tolerant, sensitive, generic ADA immunoassay has been developed and validated for measuring ADA in cynomolgus monkey serum samples, allowing for immediate qualification of future monoclonal antibody biotherapeutics. This approach allows us to differentiate complexed and free ADA in a rapidly deployable manner when needed.

Engineering therapeutic monoclonal antibodies

The use of human antibodies as biologic therapeutics has revolutionized patient care throughout fields of medicine. As our understanding of the many roles antibodies play within our natural immune responses continues to advance, so will the number of therapeutic indications for which an mAb will be developed. The great breadth of function, long half-life, and modular structure allow for nearly limitless therapeutic possibilities. Human antibodies can be rationally engineered to enhance their desired immune functions and eliminate those that may result in unwanted effects. Antibody therapeutics now often start with fully human variable regions, either acquired from genetically engineered humanized mice or from the actual human B cells. These variable genes can be further engineered by widely used methods for optimization of their specificity through affinity maturation, random mutagenesis, targeted mutagenesis, and use of in silico approaches. Antibody isotype selection and deliberate mutations are also used to improve efficacy and tolerability by purposeful fine-tuning of their immune effector functions. Finally, improvements directed at binding to the neonatal Fc receptor can endow therapeutic antibodies with unbelievable extensions in their circulating half-life. The future of engineered antibody therapeutics is bright, with the global mAb market projected to exhibit compound annual growth, forecasted to reach a revenue of nearly half a trillion dollars in 2030.

Advanced control strategies for continuous capture of monoclonal antibodies based upon biolayer interferometry

The semi and fully continuous production of monoclonal antibodies (mAbs) has been gaining traction as a lower cost, and efficient production of mAbs to broaden patient access. To be truly flexible and adaptive to process demands, the industry has lacked sufficient advanced control strategies. The variation of the upstream product concentration typically cannot be handled by the downstream capture step, which is configured for a constant feed concentration and fixed binding capacity. This inflexibility leads to losses of efficiency and product yield. This study shows that these challenges can be overcome by a novel advanced control strategy concept that includes dynamic control throughout a perfusion bioreactor, with cell retention by alternating tangential flow, integrated with simulated moving bed (SMB) multi-column chromatography. The automation workflow and advanced control strategy were implemented through the use of a visual programming development environment. This enabled dynamic flow control across the upstream and downstream process integrated with a dynamic column loading of the SMB. A sensor prototype, based on continuous biolayer interferometry measurements was applied to detect mAb breakthrough within the last column flow-through to manage column switching. This novel approach provided higher specificity and lower background signal compared to commonly used spectroscopy methods, resulting in an optimized resin utilization while simultaneously avoiding product loss. The dynamic loading was found to provide a twofold increase of the mAb concentration in the eluate compared to a conservative approach with a predefined recipe with similar impurity removal. This concept shows that advanced control strategies can lead to significant process efficiency and yield improvement.

Effect of Bamlanivimab as Monotherapy or in Combination with Etesevimab or Sotrovimab on Persistently High Viral Load in Patients with Mild-to-Moderate COVID-19: A Randomized, Phase 2 BLAZE-4 Trial

INTRODUCTION

Treatment with monoclonal antibodies provides rapid, passive immunity and may stop COVID-19 disease progression. The study evaluated the effect of bamlanivimab (BAM) or BAM + etesevimab (ETE)/sotrovimab compared to placebo on SARS-CoV-2 viral load in patients with COVID-19.

METHODS

The phase 2, randomized, single-dose study included patients aged between ≥ 18 and < 65 years, not hospitalized at the time of randomization, and had ≥ 1 mild or moderate COVID-19 symptoms. Study included arms 1-6 (placebo, BAM 175 mg + ETE 350 mg, BAM 700 mg + ETE 1400 mg, BAM 2800 mg + ETE 2800 mg, BAM 700 mg alone, and BAM 350 mg + ETE 700 mg, respectively), BAM 700 mg + ETE 700 mg unintentional dosing; and arms 7 and 8 (BAM 700 mg + sotrovimab 500 mg and placebo, respectively). The primary endpoint was proportion of patients with SARS-CoV-2 log viral load > 5.27 on day 7 (persistently high viral load [PHVL]) who received BAM or BAM + (ETE or sotrovimab).

RESULTS

A total of 725 patients, mean age 39.6 years (range 18-75 years), 50.2% male were randomized and infused with study drug in arms 1-6; and a total 202 patients, mean age 38 years (range 18-63 years), 53.5% female were randomized and infused with study drug in arms 7 and 8. A significantly lower proportion of patients in arms 2-6 and arm 7 experienced PHVL on day 7 compared to placebo. On day 7, patients in arms 2, 3, and 6 consistently experienced significantly greater reduction in viral load than placebo. Significant improvement was observed in time to viral load clearance and time to symptom improvement by day 29 in some arms compared to placebo. No new safety concerns were observed with drug combinations.

CONCLUSION

The study demonstrated that a significantly lower proportion of patients with mild-to-moderate COVID-19 treated with BAM or BAM + (ETE or sotrovimab) experienced a PHVL at day 7.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT04634409.

TLR4 Ligation by eNAMPT, a Novel DAMP, is Essential to Sulfur Mustard- Induced Inflammatory Lung Injury and Fibrosis

Objective

Human and preclinical studies of sulfur mustard (SM)-induced acute and chronic lung injuries highlight the role of unremitting inflammation. We assessed the utility of targeting the novel DAMP and TLR4 ligand, eNAMPT (extracellular nicotinamide phosphoribosyltransferase), utilizing a humanized mAb (ALT-100) in rat models of SM exposure.

Methods

Acute (SM 4.2 mg/kg, 24 hrs), subacute (SM 0.8 mg/kg, day 7), subacute (SM 2.1 mg/kg, day 14), and chronic (SM 1.2 mg/kg, day 29) SM models were utilized.

Results

Each SM model exhibited significant increases in eNAMPT expression (lung homogenates) and increased levels of phosphorylated NFkB and NOX4. Lung fibrosis (Trichrome staining) was observed in both sub-acute and chronic SM models in conjunction with elevated smooth muscle actin (SMA), TGFβ, and IL-1β expression. SM-exposed rats receiving ALT-100 (1 or 4 mg/kg, weekly) exhibited increased survival, highly significant reductions in histologic/biochemical evidence of lung inflammation and fibrosis (Trichrome staining, decreased pNFkB, SMA, TGFβ, NOX4), decreased airways strictures, and decreased plasma cytokine levels (eNAMPT, IL-6, IL-1β. TNFα).

Conclusion

The highly druggable, eNAMPT/TLR4 signaling pathway is a key contributor to SM-induced ROS production, inflammatory lung injury and fibrosis. The ALT-100 mAb is a potential medical countermeasure to address the unmet need to reduce SM-associated lung pathobiology/mortality.

Re-Engineering Therapeutic Anti-Aβ Monoclonal Antibody to Target Amyloid Light Chain

Amyloidosis involves the deposition of misfolded proteins. Even though it is caused by different pathogenic mechanisms, in aggregate, it shares similar features. Here, we tested and confirmed a hypothesis that an amyloid antibody can be engineered by a few mutations to target a different species. Amyloid light chain (AL) and β-amyloid peptide (Aβ) are two therapeutic targets that are implicated in amyloid light chain amyloidosis and Alzheimer's disease, respectively. Though crenezumab, an anti-Aβ antibody, is currently unsuccessful, we chose it as a model to computationally design and prepare crenezumab variants, aiming to discover a novel antibody with high affinity to AL fibrils and to establish a technology platform for repurposing amyloid monoclonal antibodies. We successfully re-engineered crenezumab to bind both Aβ42 oligomers and AL fibrils with high binding affinities. It is capable of reversing Aβ42-oligomers-induced cytotoxicity, decreasing the formation of AL fibrils, and alleviating AL-fibrils-induced cytotoxicity in vitro. Our research demonstrated that an amyloid antibody could be engineered by a few mutations to bind new amyloid sequences, providing an efficient way to reposition a therapeutic antibody to target different amyloid diseases.

Online multimethod platform for comprehensive characterization of monoclonal antibodies in cell culture fluid from a single sample injection - Intact protein workflow

BACKGROUND

Therapeutic monoclonal antibodies (mAbs) comprise a large structural variability with respect to charge, size and post-translational modifications. These critical quality attributes (CQAs) need to be assessed during and after the production of mAbs. This normally requires off-line purification and sample preparation as well as several chromatographic selectivities, which makes the whole process time-consuming and error-prone. To improve on this, we developed an integrated and automated multi-dimensional analytical platform for the simultaneous assessment of multiple CQAs of mAbs in cell culture fluid (CCF) from upstream processes.

RESULTS

The on-line system allows mAb characterization at the intact level, combining protein A affinity chromatography (ProtA) with size-exclusion, ion-exchange, and reversed-phase liquid chromatographic modes with UV and mass spectrometric detection. Multiple heart cuts of a single mAb elution band from ProtA are stored in 20-μL loops and successively sent to the multimethod options in the second dimension. ProtA loading and elution conditions and their compatibility with second-dimension LC modes were studied and optimized. Subsequently, heart-cutting and valve-switching schemes were investigated to achieve effective and reproducible analyses. The applicability of the developed workflow was demonstrated by the direct analysis (i.e. not requiring off-line sample preparation) of a therapeutic mAb in CCF, obtaining useful information on accurate molecular mass, glycosylation, and charge and size variants of the mAb product at the same time and in just over 1 h.

SIGNIFICANCE

The developed multidimensional platform is the first system that allows for multiple fractions from a single ProtA band to be characterized using different chromatographic selectivities in a single run allowing direct correlation between CQAs. The performance of the system is comparable to established off-line methods, fully compatible with upstream process samples, and provides a significant time-reduction of the characterization procedure.

In Vitro Combinatorial Activity of Direct Acting Antivirals and Monoclonal Antibodies against the Ancestral B.1 and BQ.1.1 SARS-CoV-2 Viral Variants

Combination antiviral therapy may be helpful in the treatment of SARS-CoV-2 infection; however, no clinical trial data are available, and combined use of direct-acting antivirals (DAA) and monoclonal antibodies (mAb) has been reported only anecdotally. To assess the cooperative effects of dual drug combinations in vitro, we used a VERO E6 cell-based in vitro system with the ancestral B.1 or the highly divergent BQ.1.1 virus to test pairwise combinations of the licensed DAA, including nirmatrelvir (NRM), remdesivir (RDV) and the active metabolite of molnupiravir (EIDD-1931) as well the combination of RDV with four licensed mAbs (sotrovimab, bebtelovimab, cilgavimab, tixagevimab; tested only with the susceptible B.1 virus). According to SynergyFinder 3.0 summary and weighted scores, all the combinations had an additive effect. Within DAA/DAA combinations, paired scores with the B.1 and BQ.1.1 variants were comparable. In the post hoc analysis weighting synergy by concentrations, several cases of highly synergistic scores were detected at specific drug concentrations, both for DAA/DAA and for RDV/mAb combinations. This was supported by in vitro confirmation experiments showing a more than a linear shift of a drug-effective concentration (IC50) at increasing concentrations of the companion drug, although the effect was prominent with DAA/DAA combinations and minimal or null with RDV/mAb combinations. These results support the cooperative effects of dual drug combinations in vitro, which should be further investigated in animal models before introduction into the clinic.

An eNAMPT-neutralizing mAb reduces post-infarct myocardial fibrosis and left ventricular dysfunction

Myocardial infarction (MI) triggers adverse ventricular remodeling (VR), cardiac fibrosis, and subsequent heart failure. Extracellular nicotinamide phosphoribosyltransferase (eNAMPT) is postulated to play a significant role in VR processing via activation of the TLR4 inflammatory pathway. We hypothesized that an eNAMPT specific monoclonal antibody (mAb) could target and neutralize overexpressed eNAMPT post-MI and attenuate chronic cardiac inflammation and fibrosis. We investigated humanized ALT-100 and ALT-300 mAb with high eNAMPT-neutralizing capacity in an infarct rat model to test our hypothesis. ALT-300 was 99mTc-labeled to generate 99mTc-ALT-300 for imaging myocardial eNAMPT expression at 2 hours, 1 week, and 4 weeks post-IRI. The eNAMPT-neutralizing ALT-100 mAb (0.4 mg/kg) or saline was administered intraperitoneally at 1 hour and 24 hours post-reperfusion and twice a week for 4 weeks. Cardiac function changes were determined by echocardiography at 3 days and 4 weeks post-IRI. 99mTc-ALT-300 uptake was initially localized to the ischemic area at risk (IAR) of the left ventricle (LV) and subsequently extended to adjacent non-ischemic areas 2 hours to 4 weeks post-IRI. Radioactive uptake (%ID/g) of 99mTc-ALT-300 in the IAR increased from 1 week to 4 weeks (0.54 ± 0.16 vs. 0.78 ± 0.13, P < 0.01). Rats receiving ALT-100 mAb exhibited significantly improved myocardial histopathology and cardiac function at 4 weeks, with a significant reduction in the collagen volume fraction (%LV) compared to controls (21.5 ± 6.1% vs. 29.5 ± 9.9%, P < 0.05). Neutralization of the eNAMPT/TLR4 inflammatory cascade is a promising therapeutic strategy for MI by reducing chronic inflammation, fibrosis, and preserving cardiac function.

Determination of Binding Affinity of Antibodies to HIV-1 Recombinant Envelope Glycoproteins, Pseudoviruses, Infectious Molecular Clones, and Cell-Expressed Trimeric gp160 Using Microscale Thermophoresis

Developing a preventative vaccine for HIV-1 has been a global priority. The elicitation of broadly neutralizing antibodies (bNAbs) against a broad range of HIV-1 envelopes (Envs) from various strains appears to be a critical requirement for an efficacious HIV-1 vaccine. To understand their ability to neutralize HIV-1, it is important to characterize the binding characteristics of bNAbs. Our work is the first to utilize microscale thermophoresis (MST), a rapid, economical, and flexible in-solution temperature gradient method to quantitatively determine the binding affinities of bNAbs and non-neutralizing monoclonal antibodies (mAbs) to HIV-1 recombinant envelope monomer and trimer proteins of different subtypes, pseudoviruses (PVs), infectious molecular clones (IMCs), and cells expressing the trimer. Our results demonstrate that the binding affinities were subtype-dependent. The bNAbs exhibited a higher affinity to IMCs compared to PVs and recombinant proteins. The bNAbs and mAbs bound with high affinity to native-like gp160 trimers expressed on the surface of CEM cells compared to soluble recombinant proteins. Interesting differences were seen with V2-specific mAbs. Although they recognize linear epitopes, one of the antibodies also bound to the Envs on PVs, IMCs, and a recombinant trimer protein, suggesting that the epitope was not occluded. The identification of epitopes on the envelope surface that can bind to high affinity mAbs could be useful for designing HIV-1 vaccines and for down-selecting vaccine candidates that can induce high affinity antibodies to the HIV-1 envelope in their native conformation.

Anti-Ebola virus mAb 3A6 with unprecedented potency protects highly viremic animals from fatal outcome and physically lifts its glycoprotein target from the virion membrane

Monoclonal antibodies (mAbs) against Ebola virus (EBOV) glycoprotein (GP1,2) are the standard of care for Ebola virus disease (EVD). Anti-GP1,2 mAbs targeting the stalk and membrane proximal external region (MPER) potently neutralize EBOV in vitro. However, their neutralization mechanism is poorly understood because they target a GP1,2 epitope that has evaded structural characterization. Moreover, their in vivo efficacy has only been evaluated in the mouse model of EVD. Using x-ray crystallography and cryo-electron tomography of 3A6 complexed with its stalk- GP1,2 MPER epitope we reveal a novel mechanism in which 3A6 elevates the stalk or stabilizes a conformation of GP1,2 that is lifted from the virion membrane. In domestic guinea pig and rhesus monkey EVD models, 3A6 provides therapeutic benefit at high viremia levels, advanced disease stages, and at the lowest dose yet demonstrated for any anti-EBOV mAb-based monotherapy. These findings can guide design of next-generation, highly potent anti-EBOV mAbs.

Ubiquitin: Characterization of a Host Cell Protein Covalently Attached to a Monoclonal Antibody Product by LC-MS/MS

Host cell protein (HCP) characterization is a crucial quality parameter for biotherapeutic drug safety and stability. With a liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach, we identified ubiquitin in ultrafiltration/diafiltration (UF/DF) pools of one of our monoclonal antibody (mAb) products. Since ubiquitin occurs physiologically as a post-translational modification (PTM) involved in many cellular functions, we suspected the possibility that if identified as an HCP, it may occur as a covalent modification on the mAb. In fact, in this study we characterized and quantified the ubiquitin modification on the Fc domain of mAbX by data dependent acquisition (DDA) and data independent acquisition (DIA) - MS workflows. Covalent binding and site localization were confirmed by identifying a characteristic diglycine motif on the modified peptide. Initially observed reduced detectability of ubiquitin in samples prepared with native digestion was attributed to impaired digestion and subsequent removal along with the mAb in the precipitation step. Our work has contributed to a better understanding of ubiquitin as an HCP considering its specific features such as occurrence in different topologies and provided insight into how covalent binding to a drug product can affect its identification by MS when native digestion conditions are used.

Facile generation of biepitopic antibodies with intrinsic agonism for activating receptors in the tumor necrosis factor superfamily

Agonist antibodies that activate cellular receptors are being pursued for therapeutic applications ranging from neurodegenerative diseases to cancer. For the tumor necrosis factor (TNF) receptor superfamily, higher-order clustering of three or more receptors is key to their potent activation. This can be achieved using antibodies that recognize two unique epitopes on the same receptor and mediate receptor superclustering. However, identifying compatible pairs of antibodies to generate biepitopic antibodies (also known as biparatopic antibodies) for activating TNF receptors typically requires animal immunization and is a laborious and unpredictable process. Here, we report a simple method for systematically identifying biepitopic antibodies that potently activate TNF receptors without the need for additional animal immunization. Our approach uses off-the-shelf, receptor-specific IgG antibodies, which lack intrinsic (Fc-gamma receptor-independent) agonist activity, to first block their corresponding epitopes. Next, we perform selections for single-chain antibodies from human nonimmune libraries that bind accessible epitopes on the same ectodomains using yeast surface display and fluorescence-activated cell sorting. The selected single-chain antibodies are finally fused to the light chains of IgGs to generate human tetravalent antibodies that engage two different receptor epitopes and mediate potent receptor activation. We highlight the broad utility of this approach by converting several existing clinical-stage antibodies against TNF receptors, including ivuxolimab and pogalizumab against OX40 and utomilumab against CD137, into biepitopic antibodies with highly potent agonist activity. We expect that this widely accessible methodology can be used to systematically generate biepitopic antibodies for activating other receptors in the TNF receptor superfamily and many other receptors whose activation is dependent on strong receptor clustering.

Characterization of novel CD19-specific VHHs isolated from a camelid immune library by phage display

BACKGROUND

Monoclonal antibody (mAb)-based immunotherapies have achieved promising outcomes in the treatment of immunological and oncological indications. CD19 is considered one of the most qualified antigens in the treatment of B-cell neoplasms. VHHs (nanobodies) are known for their physicochemical advantages over conventional mAbs rendering them suitable therapeutics and diagnostic tools. Herein, we aimed to isolate CD19-specific VHHs from a novel immune library using phage display.

METHODS

An immune VHH gene library was constructed. Using phage display and after five biopanning rounds, two monoclonal CD19-specific VHHs were isolated. The selected VHHs were expressed, purified, and characterized in terms of their affinity, specificity, sensitivity, and ability to target CD19-positive cell lines. Moreover, in silico analyses were employed for further characterization.

RESULTS

A VHH library was developed, and because the outputs of the 4th biopanning round exhibited the most favorable characteristics, a panel of random VHHs was selected from them. Ultimately, two of the most favorable VHHs were selected and DNA sequenced (designated as GR37 and GR41). Precise experiments indicated that GR37 and GR41 exhibited considerable specificity, sensitivity, and affinity (1.15 × 107 M-1 and 2.08 × 107 M-1, respectively) to CD19. Flow cytometric analyses revealed that GR37 and GR41 could bind CD19 on the surface of cell lines expressing the antigen. Moreover, in silico experiments predicted that both VHHs target epitopes that are distinct from that targeted by the CD19-specific single-chain variable fragment (scFv) FMC63.

CONCLUSION

The selected VHHs can be used as potential targeting tools for the development of CD19-based immunotherapeutics.

Localization in vivo and in vitro confirms EnApiAP2 protein encoded by ENH_00027130 as a nuclear protein in Eimeria necatrix

Introduction

Apicomplexan AP2 family of proteins (ApiAP2) are transcription factors (TFs) that regulate parasite growth and development, but little is known about the ApiAP2 TFs in Eimeria spp. ENH_00027130 sequence is predicted to encode a Eimeria necatrix ApiAP2 protein (EnApiAP2).

Methods

The cDNAs encoding full-length and truncated EnApiAP2 protein were cloned and sequenced, respectively. Then, the two cDNAs were cloned into the pET28a(+) expression vector and expressed expressed in Escherichia coli BL21. The mouse polyclonal antibody (pAb) and monoclonal antibody (mAb) against recombinant EnApiAP2 (rEnApiAP2) and EnApiAP2tr (rEnApiAP2tr) were prepared and used to localize the native EnApiAP2 protein in E. necatrix, respectively. Finally, the recombinant pEGFP-C1-ΔNLS-EnApiAP2s (knockout of a nuclear localization sequence, NLS) and pEGFP-C1-EnApiAP2 plasmid were constructed and transfected into DF-1 cells, respectively, to further observe subcellular localization of EnApiAP2 protein.

Results

The EnApiAP2 gene had a size of 5019 bp and encoded 1672 amino acids, containing a conserved AP2 domain with a secondary structure consisting of an α-helix and three antiparallel β-strands. The rEnApiAP2 and rEnApiAP2tr were predominantly expressed in the form of inclusion bodies, and could be recognized by the 6×His tag mAb and the serum of convalescent chickens after infection with E. necatrix, respectively. The native EnApiAP2 protein was detected in sporozoites (SZ) and second generation merozoites (MZ-2) extracts, with a size of approximately 210 kDa. A quantitative real-time PCR (qPCR) analysis showed that the transcription level of EnApiAP2 was significantly higher in SZ than in MZ-2, third generation merozoites (MZ-3) and gametocytes (P<0.01). EnApiAP2 protein was localized in the nuclei of SZ, MZ-2 and MZ-3 of E. necatrix. The protein of EnApiAP2 was localized in the nucleus of the DF-1 cells, whereas the ΔNLS-EnApiAP2 was expressed in the cytoplasm, which further confirmed that EnApiAP2 is nucleoprotein.

Discussion

EnApiAP2 protein encoded by ENH_00027130 sequence was localized in the nucleus of E. necatrix parasites, and relied on the NLS for migration to DF-1 cell nucleus. The function of EnApiAP2 need further study.

Transportation of mAb Dosing Solution in Intravenous Bag: Impact of Manual, Vehicle, and Pneumatic Tube System Transportation Methods on Product Quality

Monoclonal antibody (mAb) products for intravenous (IV) administration generally require aseptic compounding with a commercial diluent within a pharmacy. The prepared dosing solution in the IV bag may be transported to the dosing location via manual, vehicular, pneumatic tube system (PTS), or a combination of these methods. In this study, the type and level of physical stresses associated with these three methods and their product quality impact for relatively sensitive and stable mAbs were assessed. Vibration was found to be the main stress associated with manual and vehicle transportation methods, although this was at a relatively low level (<1 GRMS/Root-Mean-Square Acceleration). Shock and drop events, at relatively low levels, were also observed with these methods. PTS transportation showed substantially more intense shock, vibration, and drop stresses and the measured levels were up to 91 G/force of acceleration or deceleration, 3.7 GRMS and 39 G, respectively. Using a foam padding insert for PTS transportation reduced the shock level considerably (91 G to 59 G). Transportation of mAb dosing solutions in IV bags via different methods including PTS transportation variables caused a small increase in the subvisible particle counts and there was no change in submicrometer particle distribution. No visible particles and no significant change to soluble aggregate levels were observed after transportation. Strategies such as removal of IV bag headspace prior to transport and in-line filtration poststress reduced the subvisible particles counts. All tested transportation conditions showed negligible impact on other product quality attributes tested. Removal of IV bag headspace prior to PTS transport prevented formation of micro air bubbles and foaming compared to the unaltered IV bag. This study shows examples where manual, vehicle, and PTS transport methods did not significantly impact product quality, and provides evidence that mAb products that are appropriately stabilized in the dosing solution (e.g., with a surfactant) can be transported via a PTS.

Direct long-acting antibodies: updating the language of RSV prevention to reflect the evolution of mAbs

Introduction

The language of medicine is constantly evolving, typically to better describe a new understanding of disease, adjust to changing social sensibilities, or simply to reflect a new drug class or category. We address the need for an updated language around monoclonal antibodies, or "mAbs" - a widely used medical term, but one which is now too general to accurately reflect the range of mAb pharmaceuticals, their effects, and the intended patients.

Methods

The question of "what should we call a monoclonal antibody immunisation against respiratory syncytial virus (RSV) to ensure accurate understanding of the product?" was the basis for a virtual advisory panel in May 2022. The panel was convened by Sanofi with the intention of reviewing appropriate language in terminology in the context of mAb-based prophylaxis for RSV. The panel comprised several global experts on RSV and vaccination, a trained linguist specialising in doctor-patient interactions and medical language, and several experts in marketing and communications.

Results

We suggest the term "Direct Long-acting Antibody" (DLA) for a specific sub-class of mAbs for use in prevention of RSV disease in infants. This terminology should differentiate from other mAbs, which are generally not used as therapies in infants.

Discussion and Conclusions

This change will more accurately convey the specific mode of action of a mAb in infants, and how it could impact the prevention of communicable diseases: this class of mAbs is not an active treatment, but rather will offer direct and rapid protection lasting at least 5 months.

Possibilities and limitations of α-relaxation data of amorphous freeze-dried cakes to predict long term IgG1 antibody stability

The value of correlating global α-relaxations with long term protein stability after freeze-drying is inconsistently reported. This study aims to clarify whether and to what extend the long term stability of a freeze-dried protein formulation can be predicted with this method. For this purpose, the α-relaxation parameter τβ [h] of freshly prepared freeze-dried products is obtained by isothermal microcalorimetry. The concept is, that molecular movements in the amorphous matrix are strongly reduced in cakes with longer relaxation time and the product should therefore be more resistant against aggregation. To increase τβ in comparison to a conventional freeze-drying cycle, aggressive drying cycles including structural collapse of the product as well as tempering protocols after freeze-drying are applied. The τβ values are correlated with the aggregation rate of a freeze-dried IgG1 monoclonal antibody measured with high performance size exclusion chromatography. The antibody was used in its market formulation and 6 further compositions. A weak correlation between α-relaxation times and IgG1 aggregation was found. A higher mobility level through increased residual moisture helped to improve the correlation.

In Vitro Efficacy of Antivirals and Monoclonal Antibodies against SARS-CoV-2 Omicron Lineages XBB.1.9.1, XBB.1.9.3, XBB.1.5, XBB.1.16, XBB.2.4, BQ.1.1.45, CH.1.1, and CL.1

The spread of COVID-19 continues, expressed by periodic wave-like increases in morbidity and mortality. The reason for the periodic increases in morbidity is the emergence and spread of novel genetic variants of SARS-CoV-2. A decrease in the efficacy of monoclonal antibodies (mAbs) has been reported, especially against Omicron subvariants. There have been reports of a decrease in the efficacy of specific antiviral drugs as a result of mutations in the genes of non-structural proteins. This indicates the urgent need for practical healthcare to constantly monitor pathogen variability and its effect on the efficacy of preventive and therapeutic drugs. As part of this study, we report the results of the continuous monitoring of COVID-19 in Moscow using genetic and virological methods. As a result of this monitoring, we determined the dominant genetic variants and identified the variants that are most widespread, not only in Moscow, but also in other countries. A collection of viruses from more than 500 SARS-CoV-2 isolates has been obtained and characterized. The genetic lines XBB.1.9.1, XBB.1.9.3, XBB.1.5, XBB.1.16, XBB.2.4, BQ.1.1.45, CH.1.1, and CL.1, representing the greatest concern, were identified among the dominant variants. We studied the in vitro efficacy of mAbs Tixagevimab + Cilgavimab (Evusheld), Sotrovimab, Regdanvimab, Casirivimab + Imdevimab (Ronapreve), and Bebtelovimab, as well as the specific antiviral drugs Remdesivir, Molnupiravir, and Nirmatrelvir, against these genetic lines. At the current stage of the COVID-19 pandemic, the use of mAbs developed against early SARS-CoV-2 variants has little prospect. Specific antiviral drugs retain their activity, but further monitoring is needed to assess the risk of their efficacy being reduced and adjust recommendations for their use.

Simplifying complex antibody engineering using machine learning

Machine learning is transforming antibody engineering by enabling the generation of drug-like monoclonal antibodies with unprecedented efficiency. Unsupervised algorithms trained on massive and diverse protein sequence datasets facilitate the prediction of panels of antibody variants with native-like intrinsic properties (e.g., high stability), greatly reducing the amount of subsequent experimentation needed to identify specific candidates that also possess desired extrinsic properties (e.g., high affinity). Additionally, supervised algorithms, which are trained on deep sequencing datasets obtained after enrichment of in vitro antibody libraries for one or more specific extrinsic properties, enable the prediction of antibody variants with desired combinations of extrinsic properties without the need for additional screening. Here we review recent advances using both machine learning approaches and how they are impacting the field of antibody engineering as well as key outstanding challenges and opportunities for these paradigm-changing methods.

Continuous precipitation-filtration process for initial capture of a monoclonal antibody product using a four-stage countercurrent hollow fiber membrane washing step

The significant increase in product titers, coupled with the growing focus on continuous bioprocessing, has renewed interest in using precipitation as a low-cost alternative to Protein A chromatography for the primary capture of monoclonal antibody (mAb) products. In this work, a commercially relevant mAb was purified from clarified cell culture fluid using a tubular flow precipitation reactor with dewatering and washing provided by tangential flow microfiltration. The particle morphology was evaluated using an inline high-resolution optical probe, providing quantitative data on the particle size distribution throughout the precipitation process. Data were obtained in both a lab-built 2-stage countercurrent washing system and a commercial countercurrent contacting skid that provided 4 stages of continuous washing. The processes were operated continuously for 2 h with overall mAb yield of 92 ± 3% and DNA removal of nearly 3 logs in the 4-stage system. The high DNA clearance was achieved by selective redissolution of the mAb using a low pH acetate buffer. Host cell protein clearance was 0.59 ± 0.08 logs, comparable to that based on model predictions. The process mass intensity was slightly better than typical Protein A processes and could be significantly improved by preconcentration of the antibody feed material.

A CD64/FcγRI-mediated mechanism hijacks PD-1 from PD-L1/2 interaction and enhances anti-PD-1 functional recovery of exhausted T cells

Therapeutic monoclonal antibodies (mAb) targeting the immune checkpoint inhibitor programmed cell death protein 1 (PD-1) have achieved considerable clinical success in anti-cancer therapy through relieving T cell exhaustion. Blockade of PD-1 interaction with its ligands PD-L1 and PD-L2 is an important determinant in promoting the functional recovery of exhausted T cells. Here, we show that anti-PD-1 mAbs act through an alternative mechanism leading to the downregulation of PD-1 surface expression on memory CD4+ and CD8+ T cells. PD-1 receptor downregulation is a distinct process from receptor endocytosis and occurs in a CD14+ monocyte dependent manner with the CD64/Fcγ receptor I acting as the primary factor for this T cell extrinsic process. Importantly, downregulation of surface PD-1 strongly enhances antigen-specific functional recovery of exhausted PD-1+CD8+ T cells. Our study demonstrates a novel mechanism for reducing cell surface levels of PD-1 and limiting the inhibitory targeting by PD-L1/2 and thereby enhancing the efficacy of anti-PD-1 Ab in restoring T cell functionality.

The eNAMPT/TLR4 inflammatory cascade drives the severity of intra-amniotic inflammation in pregnancy and predicts infant outcomes

Introduction: Intra-amniotic inflammation (IAI) or chorioamnionitis is a common complication of pregnancy producing significant maternal morbidity/mortality, premature birth and neonatal risk of chronic lung diseases such as bronchopulmonary dysplasia (BPD). We examined eNAMPT (extracellular nicotinamide phosphoribosyltransferase), a critical inflammatory DAMP and TLR4 ligand, as a potential therapeutic target to reduce IAI severity and improve adverse fetal/neonatal outcomes. Methods: Blood/tissue samples were examined in: 1) women with histologically-proven chorioamnionitis, 2) very low birth weight (VLBW) neonates, and 3) a preclinical murine pregnancy model of IAI. Groups of pregnant IAI-exposed mice and pups were treated with an eNAMPT-neutralizing mAb. Results: Human placentas from women with histologically-proven chorioamnionitis exhibited dramatic NAMPT expression compared to placentas without chorioamnionitis. Increased NAMPT expression in whole blood from VLBW neonates (day 5) significantly predicted BPD development. Compared to untreated LPS-challenged murine dams (gestational day 15), pups born to eNAMPT mAb-treated dams (gestational days 15/16) exhibited a > 3-fold improved survival, reduced neonate lung eNAMPT/cytokine levels, and reduced development and severity of BPD and pulmonary hypertension (PH) following postnatal exposure to 100% hyperoxia days 1-14. Genome-wide gene expression studies of maternal uterine and neonatal cardiac tissues corroborated eNAMPT mAb-induced reductions in inflammatory pathway genes. Discussion: The eNAMPT/TLR4 inflammatory pathway is a highly druggable contributor to IAI pathobiology during pregnancy with the eNAMPT-neutralizing mAb a novel therapeutic strategy to decrease premature delivery and improve short- and long-term neonatal outcomes. eNAMPT blood expression is a potential biomarker for early prediction of chronic lung disease among premature neonates.

Substrate Derived Sequences Act as Subsite Blocking Motifs in Protease Inhibitory Antibodies

Proteases are involved in many physiologic processes, and dysregulated proteolysis is basis of a variety of diseases. Specific inhibition of pathogenetic proteases via monoclonal antibodies therefore holds significant therapeutic promise. Inspired by the competitive mechanism utilized by many naturally occurring and man-made protease inhibitors, we hypothesized that substrate-like peptide sequences can act as protease subsite blocking motifs if they occupy only one side of the reaction center. To test this hypothesis, a degenerate codon library representing MMP-14 substrate profiles at P1-P5' positions was constructed in the context of an anti-MMP-14 Fab by replacing its inhibitory motif in CDR-H3 with MMP-14 substrate repertoires. After selection for MMP-14 active-site binders by phage panning, results indicated that diverse substrate-like sequences conferring antibodies inhibitory potencies were enriched in the isolated clones. Optimal residues at each of P1-P5' positions were then identified, and the corresponding mutation combinations showed improved characteristics as effective inhibitors of MMP-14. Insights on efficient library designs for inhibitory peptide motifs were further discussed. Overall, this study proved the concept that substrate derived sequences were able to behave as the inhibitory motifs in protease specific antibodies. With accumulating data available on protease substrate profiles, we expect the approach described here can be broadly applied to facilitate the generation of antibody inhibitors targeting biomedically important proteases. This article is protected by copyright. All rights reserved.

Comprehensive N-Glycan Mapping using Parallel Reaction Monitoring LC-MS/MS

PURPOSE

Glycan composition can impact a biotherapeutic's safety and efficacy. For example, changes in the relative abundance of different glycan attributes like afucosylation, galactosylation or high-mannose content can change the properties or functions of a monoclonal antibody (mAb). While established methods can effectively characterize major glycan species in biotherapeutic drug products, there is still a need for more sensitive and specific methods that can effectively monitor low abundance species which may impact mAb function.

METHODS

Glycans released from two mAbs, adalimumab and trastuzumab, were derivatized with Rapifluor-MS™. Glycans were separated using HILIC and detected using either fluorescence (FLD) or mass spectrometry (MS). A parallel reaction monitoring (PRM) workflow was used for the MS analysis.

RESULTS AND CONCLUSION

FLD analysis identified 18 and 19 glycan peaks in adalimumab and trastuzumab, respectively. Glycan identities were determined using MS-analysis and a high number of FLD peaks containing co-eluting glycan species were observed. PRM analysis quantified 38 and 39 glycan species in adalimumab and trastuzumab, respectively, and the increase in glycans that could be identified was due to superior sensitivity and selectivity compared to FLD. Notably, many low abundance glycans identified by PRM included species that were not reported in other studies. PRM also offered several additional advantages; unique structural features could be identified using the collected MS/MS spectra and de-coupling MS acquisition and data processing simplified the transfer of methods between instruments. The results established PRM as a precise, informative tool for glycan analysis and quantitation.

PET/CT in Patients with Breast Cancer Treated with Immunotherapy

Significant advances in breast cancer (BC) treatment have been made in the last decade, including the use of immunotherapy and, in particular, immune checkpoint inhibitors that have been shown to improve the survival of patients with triple negative BC. This narrative review summarizes the studies supporting the use of immunotherapy in BC. Furthermore, the usefulness of 2-deoxy-2-[¹⁸F]fluoro-D-glucose (2-[¹⁸F]FDG) positron emission/computerized tomography (PET/CT) to image the tumor heterogeneity and to assess treatment response is explored, including the different criteria to interpret 2-[¹⁸F]FDG PET/CT imaging. The concept of immuno-PET is also described, by explaining the advantages of mapping treatment targets with a non-invasive and whole-body tool. Several radiopharmaceuticals in the preclinical phase are referred too, and, considering their promising results, translation to human studies is needed to support their use in clinical practice. Overall, this is an evolving field in BC treatment, despite PET imaging developments, the future trends also include expanding immunotherapy to early-stage BC and using other biomarkers.

Immune Prophylaxis Targeting the Respiratory Syncytial Virus (RSV) G Protein

The respiratory syncytial virus (RSV) causes significant respiratory disease in young infants and the elderly. Immune prophylaxis in infants is currently limited to palivizumab, an anti-RSV fusion (F) protein monoclonal antibody (mAb). While anti-F protein mAbs neutralize RSV, they are unable to prevent aberrant pathogenic responses provoked by the RSV attachment (G) protein. Recently, the co-crystal structures of two high-affinity anti-G protein mAbs that bind the central conserved domain (CCD) at distinct non-overlapping epitopes were solved. mAbs 3D3 and 2D10 are broadly neutralizing and block G protein CX3C-mediated chemotaxis by binding antigenic sites γ1 and γ2, respectively, which is known to reduce RSV disease. Previous studies have established 3D3 as a potential immunoprophylactic and therapeutic; however, there has been no similar evaluation of 2D10 available. Here, we sought to determine the differences in neutralization and immunity to RSV Line19F infection which recapitulates human RSV infection in mouse models making it useful for therapeutic antibody studies. Prophylactic (24 h prior to infection) or therapeutic (72 h post-infection) treatment of mice with 3D3, 2D10, or palivizumab were compared to isotype control antibody treatment. The results show that 2D10 can neutralize RSV Line19F both prophylactically and therapeutically, and can reduce disease-causing immune responses in a prophylactic but not therapeutic context. In contrast, 3D3 was able to significantly (p < 0.05) reduce lung virus titers and IL-13 in a prophylactic and therapeutic regimen suggesting subtle but important differences in immune responses to RSV infection with mAbs that bind distinct epitopes.

CAR-NK cell therapy for hematological malignancies: recent updates from ASH 2022

Chimeric antigen receptor (CAR)-NK cell therapy has the advantages of a low incidence of side effects and a low cost. However, the clinical outcomes are not satisfactory due to limited antitumor effects and a limited proliferative capacity. Recently, progress in CAR-NK cell therapy has been made in NK cell engineering, target design and combination with other agents to treat relapsed or refractory hematological malignancies, especially acute myeloid leukemia and multiple myeloma. This correspondence summarizes the preclinical and clinical updates for universal CAR-NK cell therapy reported at the ASH 2022 annual meeting.

Competitive Adsorption of a Monoclonal Antibody and Nonionic Surfactant at the PDMS/Water Interface

Interfacial adsorption of monoclonal antibodies (mAbs) can cause structural deformation and induce undesired aggregation and precipitation. Nonionic surfactants are often added to reduce interfacial adsorption of mAbs which may occur during manufacturing, storage, and/or administration. As mAbs are commonly manufactured into ready-to-use syringes coated with silicone oil to improve lubrication, it is important to understand how an mAb, nonionic surfactant, and silicone oil interact at the oil/water interface. In this work, we have coated a polydimethylsiloxane (PDMS) nanofilm onto an optically flat silicon substrate to facilitate the measurements of adsorption of a model mAb, COE-3, and a commercial nonionic surfactant, polysorbate 80 (PS-80), at the siliconized PDMS/water interface using spectroscopic ellipsometry and neutron reflection. Compared to the uncoated SiO₂ surface (mimicking glass), COE-3 adsorption to the PDMS surface was substantially reduced, and the adsorbed layer was characterized by the dense but thin inner layer of 16 Å and an outer diffuse layer of 20 Å, indicating structural deformation. When PS-80 was exposed to the pre-adsorbed COE-3 surface, it removed 60 wt % of COE-3 and formed a co-adsorbed layer with a similar total thickness of 36 Å. When PS-80 was injected first or as a mixture with COE-3, it completely prevented COE-3 adsorption. These findings reveal the hydrophobic nature of the PDMS surface and confirm the inhibitory role of the nonionic surfactant in preventing COE-3 adsorption at the PDMS/water interface.

Target Antigen Attributes and Their Contributions to Clinically Approved Antibody-Drug Conjugates (ADCs) in Haematopoietic and Solid Cancers

Antibody drug conjugates (ADCs) are powerful anti-cancer therapies comprising an antibody joined to a cytotoxic payload through a chemical linker. ADCs exploit the specificity of antibodies for their target antigens, combined with the potency of cytotoxic drugs, to selectively kill target antigen-expressing tumour cells. The recent rapid advancement of the ADC field has so far yielded twelve and eight ADCs approved by the US and EU regulatory bodies, respectively. These serve as effective targeted treatments for several haematological and solid tumour types. In the development of an ADC, the judicious choice of an antibody target antigen with high expression on malignant cells but restricted expression on normal tissues and immune cells is considered crucial to achieve selectivity and potency while minimising on-target off-tumour toxicities. Aside from this paradigm, the selection of an antigen for an ADC requires consideration of several factors relating to the expression pattern and biological features of the target antigen. In this review, we discuss the attributes of antigens selected as targets for antibodies used in clinically approved ADCs for the treatment of haematological and solid malignancies. We discuss target expression, functions, and cellular kinetics, and we consider how these factors might contribute to ADC efficacy.

Comparative efficacy of tezepelumab to mepolizumab, benralizumab, and dupilumab in eosinophilic asthma: A Bayesian network meta-analysis

BACKGROUND

It is unclear how the efficacy of tezepelumab, approved for the treatment of type 2 high and low asthma, compares to the efficacy of other biologics for type 2-high asthma.

OBJECTIVES

We sought to conduct an indirect comparison of tezepelumab to dupilumab, benralizumab, and mepolizumab in the treatment of eosinophilic asthma.

METHODS

The investigators conducted a systematic review and Bayesian network meta-analyses. They identified randomized controlled trials indexed in PubMed, Embase, or Cochrane Central Register of Controlled Trials (CENTRAL) between January 1, 2000, and August 12, 2022. Outcomes included exacerbation rates, prebronchodilator FEV1, and the Asthma Control Questionnaire.

RESULTS

Ten randomized controlled trials (n = 9201) met eligibility. Tezepelumab (relative risk: 0.63; 95% credible interval [CI]: 0.46-0.86) was associated with significantly lower exacerbation rates than benralizumab and larger improvements in FEV1 compared to mepolizumab (mean difference [MD]: 66; 95% CI: -33 to 170) and benralizumab (MD: 62; 95% CI: -22 to 150), though the 95% CI crossed the null value of 0. Mepolizumab improved the Asthma Control Questionnaire score the most, but this improvement was not significantly different from that of tezepelumab (tezepelumab vs mepolizumab; MD: 0.14; 95% CI: -0.10 to 0.38). For efficacy by clinically important thresholds, tezepelumab, mepolizumab, and dupilumab achieved a >99% probability of reducing exacerbation rates by ≥50% compared to placebo, but benralizumab had only a 66% probability of doing so. Tezepelumab and dupilumab had a probability of 1.00 of improving prebronchodilator FEV1 by ≥100 mL above placebo. Compared to mepolizumab, dupilumab had >90% chance for improving FEV1 by ≥50 mL, but none of the differences between biologics exceeded 100 mL.

CONCLUSIONS

In individuals with eosinophilic asthma, tezepelumab and dupilumab were associated with greater improvements (although below clinical thresholds) in exacerbation rates and lung function than benralizumab or mepolizumab.

Part II: Matrix based scaffold lyophilization facilitates processing as a prerequisite for an innovative packaging system

On large manufacturing lines, the fill finish process of drugs is generally accomplished by filling vials and syringes with their respective deliverable doses. Glass as a final container provides excellent protection of the drug product because of its chemical inertia, gas impermeability and relative robustness. However, due to potential needle stitch issues, diluent mix ups, or the required use of complex closed system transfer devices, lyophilizate vials present a significant challenge for healthcare professionals during the correct preparation of intravenous (IV) infusions. A more suitable container could potentially minimize such shortfalls during the preparation of IV infusions. Our investigations aimed at assessing if a novel medication system, consisting of an infusion bag separated into individual dry product and liquid diluent chambers, could facilitate the storage of a lyophilized product equivalently to the current standard, a vial. By incorporating an intermediate process container into two different dual chamber bags (DCB), the stability of a model monoclonal antibody formulation (mAb) was studied. The DCBs were evaluated over a 24-week period against their liquid and lyophilized dosage form equivalents in glass vials. Their stability was assessed through investigations into protein stability, residual moisture uptake of the dry products and permeability of the foil and film materials. It could be demonstrated that the stability of the incorporated drug is highly dependent on the container configuration. Ultimately it could be shown that the storage of lyophilizates is equally possible in DCBs as it is in vials, while being stored next to the diluent within the administration device.

Development of an enzyme-linked immunosorbent assay based on viral antigen capture by anti-spike glycoprotein monoclonal antibody for detecting immunoglobulin A antibodies against porcine epidemic diarrhea virus in milk

BACKGROUND

Porcine epidemic diarrhea (PED), caused by PED virus (PEDV), is a severe enteric disease burdening the global swine industry in recent years. Especially, the mortality of PED in neonatal piglets approaches 100%. Maternal antibodies in milk, particularly immunoglobulin A (IgA) antibodies, are of great importance for protection neonatal suckling piglets against PEDV infection as passive lactogenic immunity. Therefore, appropriate detection methods are required for detecting PEDV IgA antibodies in milk. In the current study, we prepared monoclonal antibodies (mAbs) against PEDV spike (S) glycoprotein. An enzyme-linked immunosorbent assay (ELISA) was subsequently developed based on PEDV antigen capture by a specific anti-S mAb.

RESULTS

The developed ELISA showed high sensitivity (the maximum dilution of milk samples up to 1:1280) and repeatability (coefficient of variation values < 10%) in detecting PEDV IgA antibody positive and negative milk samples. More importantly, the developed ELISA showed a high coincidence rate with a commercial ELISA kit for PEDV IgA antibody detection in clinical milk samples.

CONCLUSIONS

The developed ELISA in the current study is applicable for PEDV IgA antibody detection in milk samples, which is beneficial for evaluating vaccination efficacies and neonate immune status against the virus.

Accelerated cell culture process development and characterization for cilgavimab/tixagevimab (AZD7442) for the prevention and treatment of COVID-19

The global COVID-19 pandemic ignited an unprecedented race to develop vaccines and antibody therapeutics. AstraZeneca's pursuit to provide AZD7442 (EVUSHELD), two long-acting, SARS-CoV-2 spike receptor binding domain-specific neutralizing monoclonal antibodies, to individuals at risk on highly accelerated timelines challenged our traditional ways of process development and spurred the rapid adoption of novel approaches. Conventional upstream development processes were replaced by agile strategies that combined technological advances and highly accelerated workflows. With calculated business risks and close cross-functional collaborations, this process paved the way for hyper accelerated antibody development from discovery through manufacturing, process validation, emergency use authorization filing, and global regulatory approvals. The result was initiation of commercial manufacturing at a contract manufacturing organization less than 6 months from the selection of cilgavimab and tixagevimab-a process that historically has taken close to 10 years.

Anti-G protein antibodies targeting the RSV G protein CX3C chemokine region improve the interferon response

Background

Respiratory syncytial virus (RSV) is a poor inducer of antiviral interferon (IFN) responses which result in incomplete immunity and RSV disease. Several RSV proteins alter antiviral responses, including the non-structural proteins (NS1, NS2) and the major viral surface proteins, that is, fusion (F) and attachment (G) proteins. The G protein modifies the host immune response to infection linked in part through a CX3 C chemokine motif. Anti-G protein monoclonal antibodies (mAbs), that is, clones 3D3 and 2D10 that target the G protein CX3C chemokine motif can neutralize RSV and inhibit G protein-CX3CR1 mediated chemotaxis.

Objectives

Determine how monoclonal antibodies against the RSV F and G proteins modify the type I and III IFN responses to RSV infection.

Design

As the G protein CX3 C motif is implicated in IFN antagonism, we evaluated two mAbs that block G protein CX3C-CX3CR1 interaction and compared responses to isotype mAb control using a functional cellular assay and mouse model.

Methods

Mouse lung epithelial cells (MLE-15 cells) and BALB/c mice were infected with RSV Line19 F following prophylactic mAb treatment. Cell supernatant or bronchoalveolar lavage fluid (BALF) were assayed for types I and III IFNs. Cells were interrogated for changes in IFN-related gene expression.

Results

Treatment with an anti-G protein mAb (3D3) resulted in improved IFN responses compared with isotype control following infection with RSV, partially independently of neutralization, and this was linked to upregulated SOCS1 expression.

Conclusions

These findings show that anti-G protein antibodies improve the protective early antiviral response, which has important implications for vaccine and therapeutic design.

Plain Language Summary

RSV is a leading cause of respiratory disease in infants and the elderly. The only Food and Drug Administration-approved prophylactic treatment is limited to an anti-F protein monoclonal antibody (mAb), that is, palivizumab which has modest efficacy against RSV disease. Accumulating evidence suggests that targeting the RSV attachment (G) protein may provide improved protection from RSV disease. It is known that the G protein is an IFN antagonist, and IFN has been shown to be protective against RSV disease. In this study, we compared IFN responses in mouse lung epithelial (MLE-15) cells and in mice infected with RSV Line19 F treated with anti-G protein or anti-F protein mAbs. The levels of type I and III IFNs were determined. Anti-G protein mAbs improved the levels of IFNs compared with isotype-treated controls. These findings support the concept that anti-G protein mAbs mediate improved IFN responses against RSV disease, which may enable improved treatment of RSV infections.

Employing QbD strategies to assess the impact of cell viability and density on the primary recovery of monoclonal antibodies

Quality by Design (QbD) is one of the most important tools for the implementation of Process Analytical Technology (PAT) in biopharmaceutical production. For optimal characterization of a monoclonal antibody (mAb) upstream process a stepwise approach was implemented. The upstream was divided into three process stages, namely inoculum expansion, production, and primary recovery, which were investigated individually. This approach enables analysis of process parameters and associated intermediate quality attributes as well as systematic knowledge transfer to subsequent process steps. Following previous research, this study focuses on the primary recovery of the mAb and thereby marks the final step toward a holistic characterization of the upstream process. Based on gained knowledge during the production process evaluation, the cell viability and density were determined as critical parameters for the primary recovery. Directed cell viability adjustment was achieved using cytotoxic camptothecin in a novel protocol. Additionally, the cell separation method was added to the Design of Experiments (DoE) as a qualitative factor and varied between filtration and centrifugation. To assess the quality attributes after cell separation, the bioactivity of the mAb was analyzed using a cell-based assay and the purity of the supernatant was evaluated by measurement of process related impurities (host cell protein proportion, residual DNA). Multivariate data analysis of the compiled data confirmed the hypothesis that the upstream process has no significant influence on the bioactivity of the mAb. Therefore, process control must be tuned towards high mAb titers and purity after the primary recovery, enabling optimal downstream processing of the product. To minimize amounts of host cell proteins and residual DNA the cell viability should be maintained above 85% and the cell density should be controlled around 15 × 10⁶ cells/ml during the cell removal. Thereby, this study shows the importance of QbD for the characterization of the primary recovery of mAbs and highlights the useful implementation of the stepwise approach over subsequent process stages.

Advancing humanized monoclonal antibody for counteracting fentanyl toxicity towards clinical development

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.

Bispecific Antibodies: A Novel Approach for the Treatment of Solid Tumors

Advancement in sequencing technologies allows for the identification of molecular pathways involved in tumor progression and treatment resistance. Implementation of novel agents targeting these pathways, defined as targeted therapy, significantly improves the prognosis of cancer patients. Targeted therapy also includes the use of monoclonal antibodies (mAbs). These drugs recognize specific oncogenic proteins expressed in cancer cells. However, as with many other types of targeting agents, mAb-based therapy usually fails in the long-term control of cancer progression due to the development of resistance. In many cases, resistance is caused by the activation of alternative pathways involved in cancer progression and the development of immune evasion mechanisms. To overcome this off-target resistance, bispecific antibodies (bsAbs) were developed to simultaneously target differential oncogenic pathway components, tumor-associated antigens (TAA) and immune regulatory molecules. As a result, in the last few years, several bsAbs have been tested or are being tested in cancer patients. A few of them are currently approved for the treatment of some hematologic malignancies but no bsAbs are approved in solid tumors. In this review, we will provide an overview of the state-of-the-art of bsAbs for the treatment of solid malignancies outlining their classification, design, main technologies utilized for production, mechanisms of action, updated clinical evidence and potential limitations.

IL-33 receptor inhibition in subjects with uncontrolled asthma: A randomized, placebo-controlled trial

Background

Most biologics for severe asthma target only type 2 immunity. Inhibition of IL-33 signaling has the potential to target type 2 and non-type 2 pathways.

Objective

This multicenter phase IIA study evaluated the safety and efficacy of GSK3772847, a human mAb directed against the IL-33 receptor (IL-33R) in subjects with moderate-to-severe uncontrolled asthma.

Methods

Adults with uncontrolled asthma despite inhaled corticosteroid/long-acting β2-agonist therapy received equivalent replacement medication (open-label fluticasone propionate/salmeterol [500/50 μg, twice daily]) for 2 weeks before randomization at week 0. At weeks 0, 4, 8, and 12, participants were administered blinded placebo or 10 mg/kg of intravenous GSK3772847. At week 2, salmeterol was discontinued; thereafter, fluticasone propionate was titrated by approximately 50% on weeks 4, 6, 8, and 10. Asthma control was assessed until week 16. Participants with loss of asthma control discontinued treatment. The primary end point was loss of asthma control; secondary end points were the efficacy, safety, tolerability, pharmacodynamics, and pharmacokinetics of GSK3772847.

Results

At week 16, 56 participants (81%) and 45 (66%) receiving placebo and GSK3772847, respectively, had loss of asthma control (an 18% reduction [95% credible interval = 2%-35%]). Early loss of asthma control prevented full analysis of the secondary efficacy end points after week 4. The most frequent classes of treatment-related adverse events were cardiac disorders (n = 3 [4%] in both groups) and musculoskeletal/connective tissue disorders (with GSK3772847, n = 3 [4%]; with placebo n = 0). Target engagement of IL-33R by GSK3772847 was demonstrated.

Conclusion

Treatment with GSK3772847 may be beneficial for patients with uncontrolled asthma. Further studies are warranted.

A Method for Screening Proteases That Can Specifically Hydrolyze the Epitope AA83-105 of α(s1)-Casein Allergen

Milk protein hydrolysates are common in infant formula, but some of them retain allergenicity due to incomplete hydrolysis of the epitopes for milk allergens. This study explored a method for screening proteases that could specifically hydrolyze the epitope of αs1-casein allergen. Firstly, the αs1-casein epitope AA83-105 was synthesized by the solid-phase synthesis method. Then, after purification and identification, the complete antigen was prepared through coupling with bovine serum albumin (BSA) and was used to raise monoclonal antibodies (mAb) in BALB/c mice. Additionally, an indirect competitive-enzyme-linked immunosorbent assay (icELISA) was established. The mAb raised against αs1-casein protein was used as a control. The results showed that the purity of the synthetic epitope was >90%, and the coupling rate with BSA was 6.31. The mAb subtype is IgG1, with a titer of 1:320,000. The mAb reacted specifically with αs1-casein but did not cross-react with soybean protein. The linear regression equation of the competitive inhibition curve was y = −9.22x + 100.78 (R2 = 0.9891). The detection limit of icELISA method was more sensitive, and the method showed good accuracy and repeatability. The amounts of antigen residues in papain protease hydrolysates were relatively small, and the epitope fragment was detected in papain hydrolysate via mass spectrometry. This study provides ideas and methods for screening proteases that specifically hydrolyze the epitopes of milk allergens and also provides a superior foundation for the development of an advanced hypoallergenic formula.

Maximizing hydrophobic peptide recovery in proteomics and antibody development using a mass spectrometry compatible surfactant

Peptide loss due to surface absorption can happen at any step in a protein analysis workflow and is sometimes especially deleterious for hydrophobic peptides. In this study, we found the LC-MS compatible surfactant, n-Dodecyl-β-D-maltoside (DDM), can maximize hydrophobic peptide recovery in various samples including single cell digests, mAb clinical PK samples, and mAb peptide mapping samples. In HeLa single cell proteomics analysis, more than half of all unique peptides identified were found only in DDM prepared samples, most of which had significantly higher hydrophobicities compared to peptides in control samples. In clinical PK studies, DDM enhanced hydrophobic complementarity-determining region (CDR) peptide signals significantly. The fold change of CDR peptides' intensity enhancement in DDM added samples compared to controls correlate with peptide retention time and hydrophobicity, providing guidance for surrogate peptide selection and peptide standard handling in PK studies. For peptide mapping analysis of mAbs, DDM can improve hydrophobic peptide signal and solution stability over 48 h in an autosampler at 4 °C, which can aid method qualification and transfer during drug development. Lastly, maximizing hydrophobic peptide recovery from samples dried in vacuo was achieved by DDM reconstitution, which provided higher signal for later eluting peaks and higher proteome coverage overall.

Stable nebulization and muco-trapping properties of regdanvimab/IN-006 support its development as a potent, dose-saving inhaled therapy for COVID-19

The respiratory tract represents the key target for antiviral delivery in early interventions to prevent severe COVID-19. While neutralizing monoclonal antibodies (mAb) possess considerable efficacy, their current reliance on parenteral dosing necessitates very large doses and places a substantial burden on the healthcare system. In contrast, direct inhaled delivery of mAb therapeutics offers the convenience of self-dosing at home, as well as much more efficient mAb delivery to the respiratory tract. Here, building on our previous discovery of Fc-mucin interactions crosslinking viruses to mucins, we showed that regdanvimab, a potent neutralizing mAb already approved for COVID-19 in several countries, can effectively trap SARS-CoV-2 virus-like particles in fresh human airway mucus. IN-006, a reformulation of regdanvimab, was stably nebulized across a wide range of concentrations, with no loss of activity and no formation of aggregates. Finally, nebulized delivery of IN-006 resulted in 100-fold greater mAb levels in the lungs of rats compared to serum, in marked contrast to intravenously dosed mAbs. These results not only support our current efforts to evaluate the safety and efficacy of IN-006 in clinical trials, but more broadly substantiate nebulized delivery of human antiviral mAbs as a new paradigm in treating SARS-CoV-2 and other respiratory pathologies.