Bispecific antibodies in indolent B-cell lymphomas

The advent of immunotherapy in lymphomas, beginning with Rituximab, have led to paradigm shifting treatments that are increasingly bringing a greater number of affected patients within the ambit of durable disease control and cure. Bispecific antibodies harness the properties of the immunoglobulin antibody structure to design molecules which, apart from engaging with the target tumour associated antigen, engage the host's T-cells to cause tumour cell death. Mosunetuzumab, an anti-CD20 directed bispecific antibody was the first to be approved in follicular lymphoma, this has now been followed by quick approvals of Glofitamab and Epcoritamab in diffuse large B-cell lymphomas. This article reviews contemporary data and ongoing studies evaluating the role of bispecific antibodies in indolent b-cell non Hodgkin lymphomas. This is an area of active research and presents many opportunities in advancing the treatment of indolent lymphomas and potentially forge a chemo-free treatment paradigm in this condition.

Selection of bispecific antibodies with optimal developability using FcRn‑Ph‑HPLC as an optimized FcRn affinity chromatography method

A challenge when developing therapeutic antibodies is the identification of candidates with favorable pharmacokinetics (PK) early in development. A key determinant of immunoglobulin (IgG) serum half‑life in vivo is the efficiency of pH-dependent binding to the neonatal Fc receptor (FcRn). Numerous studies have proposed techniques to assess FcRn binding of IgG-based therapeutics in vitro, enabling prediction of serum half-life prior to clinical assessment. FcRn high-performance liquid chromatography (HPLC) assays FcRn binding of therapeutic IgGs across a pH gradient, allowing the correlation of IgG column retention time to the half‑life of a therapeutic IgG in vivo. However, as FcRn retention time cannot be directly compared to an in vivo parameter, modifications to FcRn-HPLC are required to enable interpretation of the data within a physiological context, to provide more accurate estimations of serum half-life. This study presents an important modification to this method, FcRn-pH-HPLC, which reproducibly measures FcRn dissociation pH, allowing correlation with previously established half-lives of therapeutic antibodies. Furthermore, the influence of incorporating various antibody modifications, binding modules, and their orientations within IgGs and bispecifics on FcRn dissociation pH was evaluated using antibodies from the redirected optimized cell killing (ROCK®) platform. Target and effector antigen-binding domain sequences, their presentation format and orientation within a bispecific antibody alter FcRn retention; tested Fc domain modifications and incorporating stabilizing disulfide bonds had minimal effect. This study may inform the generation of mono-, bi- and multi-specific antibodies with tailored half-lives based on FcRn binding properties in vitro, to differentiate antibody-based therapeutic candidates with optimal developability.

Nebulized mRNA-Encoded Antibodies Protect Hamsters from SARS-CoV-2 Infection

Despite the success of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccines, there remains a clear need for new classes of preventatives for respiratory viral infections due to vaccine hesitancy, lack of sterilizing immunity, and for at-risk patient populations, including the immunocompromised. While many neutralizing antibodies have been identified, and several approved, to treat COVID-19, systemic delivery, large doses, and high costs have the potential to limit their widespread use, especially in low- and middle-income countries. To use these antibodies more efficiently, an inhalable formulation is developed that allows for the expression of mRNA-encoded, membrane-anchored neutralizing antibodies in the lung to mitigate SARS-CoV-2 infections. First, the ability of mRNA-encoded, membrane-anchored, anti-SARS-CoV-2 antibodies to prevent infections in vitro is demonstrated. Next, it is demonstrated that nebulizer-based delivery of these mRNA-expressed neutralizing antibodies potently abrogates disease in the hamster model. Overall, these results support the use of nebulizer-based mRNA expression of neutralizing antibodies as a new paradigm for mitigating respiratory virus infections.

Soluble α-synuclein-antibody complexes activate the NLRP3 inflammasome in hiPSC-derived microglia

Parkinson's disease is characterized by accumulation of α-synuclein (αSyn). Release of oligomeric/fibrillar αSyn from damaged neurons may potentiate neuronal death in part via microglial activation. Heretofore, it remained unknown if oligomeric/fibrillar αSyn could activate the nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family pyrin domain-containing 3 (NLRP3) inflammasome in human microglia and whether anti-αSyn antibodies could prevent this effect. Here, we show that αSyn activates the NLRP3 inflammasome in human induced pluripotent stem cell (hiPSC)-derived microglia (hiMG) via dual stimulation involving Toll-like receptor 2 (TLR2) engagement and mitochondrial damage. In vitro, hiMG can be activated by mutant (A53T) αSyn secreted from hiPSC-derived A9-dopaminergic neurons. Surprisingly, αSyn-antibody complexes enhanced rather than suppressed inflammasome-mediated interleukin-1β (IL-1β) secretion, indicating these complexes are neuroinflammatory in a human context. A further increase in inflammation was observed with addition of oligomerized amyloid-β peptide (Aβ) and its cognate antibody. In vivo, engraftment of hiMG with αSyn in humanized mouse brain resulted in caspase-1 activation and neurotoxicity, which was exacerbated by αSyn antibody. These findings may have important implications for antibody therapies aimed at depleting misfolded/aggregated proteins from the human brain, as they may paradoxically trigger inflammation in human microglia.

Pancreatic Adenocarcinoma: Unconventional Approaches for an Unconventional Disease

This review highlights current treatments, limitations, and pitfalls in the management of pancreatic cancer and discusses current research in novel targets and drug development to overcome these clinical challenges. We begin with a review of the clinical landscape of pancreatic cancer, including genetic and environmental risk factors, as well as limitations in disease diagnosis and prevention. We next discuss current treatment paradigms for pancreatic cancer and the shortcomings of targeted therapy in this disease. Targeting major driver mutations in pancreatic cancer, such as dysregulation in the KRAS and TGFβ signaling pathways, have failed to improve survival outcomes compared with nontargeted chemotherapy; thus, we describe new advances in therapy such as Ras-binding pocket inhibitors. We then review next-generation approaches in nanomedicine and drug delivery, focusing on preclinical advancements in novel optical probes, antibodies, small-molecule agents, and nucleic acids to improve surgical outcomes in resectable disease, augment current therapies, expand druggable targets, and minimize morbidity. We conclude by summarizing progress in current research, identifying areas for future exploration in drug development and nanotechnology, and discussing future prospects for management of this disease.

Triple-drug chemotherapy regimens in combination with an anti-EGFR agent in metastatic colorectal cancer - prospects from phase II clinical trials

INTRODUCTION

The addition of monoclonal antibody (mAb) epidermal growth factor receptor (EGFR) inhibitors to classic chemotherapy doublet backbones has improved survival of metastatic colorectal cancer (mCRC). However, the role of triple-drug chemotherapy regimens in combination with an anti-EGFR mAb inhibitor is not yet clear.

AREAS COVERED

The activity of triple-drug chemotherapy regimens when combined with an anti-EGFR mAb in mCRC patients is examined. We describe the overall safety and tolerability profiles based on a literature review of all published phase I and II clinical trials in this setting. Drug exposure, tumor mutational status, and metastases resectability are discussed. A review of PubMed and abstracts of major oncology congresses from 2009 to 2018, with MeSH and full-text search terms for clinical trials of anti-EGFR for 'metastatic' or 'advanced' 'colorectal cancer/adenocarcinoma' was implemented. Only English language publications were included.

EXPERT OPINION

Efficacy data from phase II trials are promising, but the safety profiles are not as encouraging; the development of severe diarrhea and acneiform rash limit the drug exposure that is critical for improved outcomes. Phase II studies of these triplet chemotherapy/anti-EGFR mAb combinations have focused on conversion therapy in liver-limited disease or in the first-line setting in advanced disease. The identification of biomarkers of response and toxicity may support the use of personalized medicine and more precise design of phase III trials.

A microbial sensor for discovering structural probes of protein misfolding and aggregation

In all cell types, protein homeostasis, or "proteostasis," is maintained by sophisticated quality control networks that regulate protein synthesis, folding, trafficking, aggregation, disaggregation, and degradation. In one notable example, Escherichia coli employ a proteostasis system that determines whether substrates of the twin-arginine translocation (Tat) pathway are correctly folded and thus suitable for transport across the tightly sealed cytoplasmic membrane. Herein, we review growing evidence that the Tat translocase itself discriminates folded proteins from those that are misfolded and/or aggregated, preferentially exporting only the former. Genetic suppressors that inactivate this mechanism have recently been isolated and provide direct evidence for the participation of the Tat translocase in structural proofreading of its protein substrates. We also discuss how this discriminatory "folding sensor" has been exploited for the discovery of structural probes (e.g., sequence mutations, pharmacologic chaperones, intracellular antibodies) that modulate the folding and solubility of virtually any protein-of-interest, including those associated with aggregation diseases (e.g., α-synuclein, amyloid-β protein). Taken together, these studies highlight the utility of engineered bacteria for rapidly and inexpensively uncovering potent anti-aggregation factors.