A pH-responsive crosslinker platform for antibody-drug conjugate (ADC) targeting delivery

Pharmaceutical innovation and advanced biotechnology in the biotech-pharmaceutical industry for antibody-drug conjugate development

Antibody-drug conjugates (ADCs), from prototypes in the 1980s to first- and second-generation products in the 2000s, and now in their multiformats, have progressed tremendously to meet oncological challenges. Currently, 13 ADCs have been approved for medical practice, with over 200 candidates in clinical trials. Moreover, ADCs have evolved into different formats, including bispecific ADCs, probody-drug conjugates, pH-responsive ADCs, target-degrading ADCs, and immunostimulating ADCs. Technologies from biopharmaceutical industries have a crucial role in the clinical transition of these novel biotherapeutics. In this review, we highlight several features contributing to the prosperity of bioindustrial ADC development. Various proprietary technologies from biopharmaceutical companies are discussed. Such advances in biopharmaceutical industries are the backbone for the success of ADCs in development and clinical application.

A Computational Perspective on the Reactivity of π-spacers in Self-Immolative Elimination Reactions

The controlled release of chemicals, especially in drug delivery, is crucial, often employing "self-immolative" spacers to enhance reliability. These spacers separate the payload from the protecting group, ensuring a more controlled release. Over the years, design rules have been proposed to improve the elimination process's reaction rate by modifying spacers with electron-donating groups or reducing their aromaticity. The spacer design is critical for determining the range of functional groups released during this process. This study explores various strategies from the literature aimed at improving release rates, focusing on the electronic nature of the spacer, its aromaticity, the electronic nature of its substituents, and the leaving groups involved in the elimination reaction. Through computational analysis, I investigate activation free energies by identifying transition states for model reactions. My calculations align qualitatively with experimental results, demonstrating the feasibility and reliability of computationally pre-screening model self-immolative eliminations. This approach allows proposing optimal combinations of spacer and leaving group for achieving the highest possible release rate.

Multipurpose Iron-Chelating Ligands Inspired by Bioavailable Molecules

Because of their capacity to bind metals, metal chelators are primarily employed for therapeutic purposes, but they can also find applications as colorimetric reagents and cleaning solutions as well as in soil remediation, electroplating, waste treatment, and so on. For instance, iron-chelation therapy, which is used to treat iron-overload disorders, involves removing excess iron from the blood through the use of particular molecules, like deferoxamine, that have the ability to chelate the metal. The creation of bioinspired and biodegradable chelating agents is a crucial objective that draws inspiration from natural products. In this context, starting from bioavailable molecules such as maltol and pyrogallol, new molecules have been synthetized and characterized by potentiometry, infrared spectroscopy and cyclic voltammetry. Finally, the ability of these to bind iron has been investigated, and the stability constants of ferric complexes are measured using spectrophotometry. These compounds offer intriguing scaffolds for an innovative class of versatile, multipurpose chelating agents.

Ex vivo mass spectrometry-based biodistribution analysis of an antibody-Resiquimod conjugate bearing a protease-cleavable and acid-labile linker

Immune-stimulating antibody conjugates (ISACs) equipped with imidazoquinoline (IMD) payloads can stimulate endogenous immune cells to kill cancer cells, ultimately inducing long-lasting anticancer effects. A novel ISAC was designed, featuring the IMD Resiquimod (R848), a tumor-targeting antibody specific for Carbonic Anhydrase IX (CAIX) and the protease-cleavable Val-Cit-PABC linker. In vitro stability analysis showed not only R848 release in the presence of the protease Cathepsin B but also under acidic conditions. The ex vivo mass spectrometry-based biodistribution data confirmed the low stability of the linker-drug connection while highlighting the selective accumulation of the IgG in tumors and its long circulatory half-life.

Enhanced therapeutic efficacy of doxorubicin against multidrug-resistant breast cancer with reduced cardiotoxicity

Doxorubicin (DOX), a commonly used anti-cancer drug, is limited by its cardiotoxicity and multidrug resistance (MDR) of tumor cells. Epigallocatechin gallate (EGCG), a natural antioxidant component, can effectively reduce the cardiotoxicity of DOX. Meanwhile, EGCG can inhibit the expression of P-glycoprotein (P-gp) and reverse the MDR of tumor cells. In this study, DOX is connected with low molecular weight polyethyleneimine (PEI) via hydrazone bond to get the pH-sensitive PEI-DOX, which is then combined with EGCG to prevent the cardiotoxicity of DOX and reverse the MDR of cancer cells. In addition, folic acid (FA) modified polyethylene glycol (PEG) (PEG-FA) is added to get the targeted system PEI-DOX/EGCG/FA. The MDR reversal and targeting ability of PEI-DOX/EGCG/FA is performed by cytotoxicity and in vivo anti-tumor activity on multidrug resistant MCF-7 cells (MCF-7/ADR). Additionally, we investigate the anti-drug resistant mechanism by Western Blot. The ability of EGCG to reduce DOX cardiotoxicity is confirmed by cardiotoxicity assay. In conclusion, PEI-DOX/EGCG/FA can inhibit the expression of P-gp and reverse the MDR in tumor cells. It also shows the ability of remove oxygen free radicals effectively to prevent the cardiotoxicity of DOX.

Redefining Precision Management of r/r Large B-Cell Lymphoma: Novel Antibodies Take on CART and BMT in the Quest for Future Treatment Strategies

The treatment paradigms for patients with relapsed large B-cell lymphoma are expanding. Chimeric antigen receptor technology (CAR-T) has revolutionized the management of these patients. Novel bispecific antibodies and antibody-drug conjugates, used as chemotherapy-free single agents or in combination with other novel therapeutics, have been quickly introduced into the real-world setting. With such a paradigm shift, patients have an improved chance of better outcomes with unpredictable complete remission rates. Additionally, the excellent tolerance of new antibodies targeting B-cell lymphomas is another motivation to broaden its use in relapsed and refractory patients. With the increasing number of approved therapy approaches, future research needs to focus on optimizing the sequence and developing new combination strategies for these antibodies, both among themselves and with other agents. Clinical, pathological, and genetic risk profiling can assist in identifying which patients are most likely to benefit from these costly therapeutic options. However, new combinations may lead to new side effects, which we must learn to deal with. This review provides a comprehensive overview of the current state of research on several innovative antibodies for the precision management of large B-cell lymphoma. It explores various treatment strategies, such as CAR-T vs. ASCT, naked antibodies, antibody-drug conjugates, bispecific antibodies, and bispecific T-cell engagers, as well as discussing the challenges and future perspectives of novel treatment strategies. We also delve into resistance mechanisms and factors that may affect decision making. Moreover, each section provides a detailed analysis of the available literature and ongoing clinical trials.

Kinetics and Mechanism of Camptothecin Release from Transferrin-Gated Mesoporous Silica Nanoparticles through a pH-Responsive Surface Linker

Stimuli-responsive nanomaterials have emerged as a promising strategy for inclusion in anticancer therapy. In particular, pH-responsive silica nanocarriers have been studied to provide controlled drug delivery in acidic tumor microenvironments. However, the intracellular microenvironment that the nanosystem must face has an impact on the anticancer effect; therefore, the design of the nanocarrier and the mechanisms that govern drug release play a crucial role in optimizing efficacy. Here, we synthesized and characterized mesoporous silica nanoparticles with transferrin conjugated on their surface via a pH-sensitive imine bond (MSN-Tf) to assess camptothecin (CPT) loading and release. The results showed that CPT-loaded MSN-Tf (MSN-Tf@CPT) had a size of ca. 90 nm, a zeta potential of -18.9 mV, and a loaded content of 13.4%. The release kinetic data best fit a first-order model, and the predominant mechanism was Fickian diffusion. Additionally, a three-parameter model demonstrated the drug-matrix interaction and impact of transferrin in controlling the release of CPT from the nanocarrier. Taken together, these results provide new insights into the behavior of a hydrophobic drug released from a pH-sensitive nanosystem.

The Dawn of a New Era: Targeting the "Undruggables" with Antibody-Based Therapeutics

The high selectivity and affinity of antibodies toward their antigens have made them a highly valuable tool in disease therapy, diagnosis, and basic research. A plethora of chemical and genetic approaches have been devised to make antibodies accessible to more "undruggable" targets and equipped with new functions of illustrating or regulating biological processes more precisely. In this Review, in addition to introducing how naked antibodies and various antibody conjugates (such as antibody-drug conjugates, antibody-oligonucleotide conjugates, antibody-enzyme conjugates, etc.) work in therapeutic applications, special attention has been paid to how chemistry tools have helped to optimize the therapeutic outcome (i.e., with enhanced efficacy and reduced side effects) or facilitate the multifunctionalization of antibodies, with a focus on emerging fields such as targeted protein degradation, real-time live-cell imaging, catalytic labeling or decaging with spatiotemporal control as well as the engagement of antibodies inside cells. With advances in modern chemistry and biotechnology, well-designed antibodies and their derivatives via size miniaturization or multifunctionalization together with efficient delivery systems have emerged, which have gradually improved our understanding of important biological processes and paved the way to pursue novel targets for potential treatments of various diseases.