Mechanism of Insoluble Aggregate Formation in a Reconstituted Solution of Spray-Dried Protein Powder

BACKGROUND

Spray-drying is considered a promising alternative drying method to lyophilization (freeze-drying) for therapeutic proteins. Particle counts in reconstituted solutions of dried solid dosage forms of biologic drug products are closely monitored to ensure product quality. We found that high levels of particles formed after reconstitution of protein powders that had been spray-dried under suboptimal conditions.

METHODS

Visible and subvisible particles were evaluated. Soluble proteins in solution before spray-drying and in the reconstituted solution of spray-dried powder were analyzed for their monomer content levels and melting temperatures. Insoluble particles were collected and analyzed by Fourier transform infrared microscopy (FTIR), and further analyzed with hydrogen-deuterium exchange (HDX).

RESULTS

Particles observed after reconstitution were shown not to be undissolved excipients. FTIR confirmed their identity as proteinaceous in nature. These particles were therefore considered to be insoluble protein aggregates, and HDX was applied to investigate the mechanism underlying aggregate formation. Heavy-chain complementarity-determining region 1 (CDR-1) in the aggregates showed significant protection by HDX, suggesting CDR-1 was critical for aggregate formation. In contrast, various regions became more conformationally dynamic globally, suggesting the aggregates have lost protein structural integrity and partially unfolded after spray-drying.

DISCUSSION

The spray-drying process could have disrupted the higher-order structure of proteins and exposed the hydrophobic residues in CDR-1 of the heavy chain, contributing to the formation of aggregate through hydrophobic interactions upon reconstitution of spray-dried powder. These results can contribute to efforts to design spray-dry resilient protein constructs and improve the robustness of the spray-drying process.

A Novel Dual-Payload ADC for the Treatment of HER2+ Breast and Colon Cancer

Antibody-drug conjugates (ADCs) have demonstrated a great therapeutic potential against cancer due to their target specificity and cytotoxicity. To exert a maximum therapeutic effect on cancerous cells, we have conjugated two different payloads to different amino acids, cysteines (cys) and lysines (lys), on trastuzumab, which is a humanised anti-HER2 monoclonal antibody. First, trastuzumab was conjugated with monomethyl auristatin E (MMAE), an antimitotic agent, through a cleavable linker (Val-Cit) to prepare ADC (Tmab-VcMMAE). Then, the ADC (Tmab-VcMMAE) was conjugated with a second antimitotic agent, Mertansine (DM1), via a non-cleavable linker Succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC) to form a dual conjugate (Tmab-VcMMAE-SMCC-DM1). Our results indicated that the dual-payload conjugate, Tmab-VcMMAE-SMCC-DM1, had a synergistic and superior cytotoxic effect compared to trastuzumab alone. Ultimately employing a dual conjugation approach has the potential to overcome treatment-resistance and tumour recurrences and could pave the way to employ other payloads to construct dual (or multiple) payload complexes.

An Overview of the Development and Preclinical Evaluation of Antibody-Drug Conjugates for Non-Oncological Applications

Typically, antibody-drug conjugates (ADCs) are made up of a humanized antibody and a small-molecule medication connected by a chemical linker. ADCs' ability to deliver cytotoxic agents to the specific site with reduced side effects showed promising results in oncology. To date, fourteen ADCs have been approved by the US Food and Drug Administration, and approximately 297 ADCs are in pre-clinical/clinical stages in the oncology area. Inspired by these outcomes, a few scientists explored the potential of antibody-drug conjugates in non-oncological conditions such as arthritis, myasthenia gravis, immunological disorders, and kidney failure. However, there are limited data available on the non-oncological applications of antibody-drug conjugates. This current review focuses on the non-oncological applications of antibody-drug conjugates, their developmental studies, testing procedures, in vitro evaluations, and pre-clinical testing. Additionally, a summary of the restrictions, difficulties, and prospects for ADCs in non-oncological applications is provided.

Kinetic studies and CFD-based reaction modeling for insights into the scalability of ADC conjugation reactions

The manufacturing of antibody-drug conjugates (ADCs) involves the addition of a cytotoxic small-molecule linker-drug (= payload) to a solution of functionalized antibodies. For the development of robust conjugation processes, initially small-scale reaction tubes are used which requires a lot of manual handling. Scale-up to larger reaction vessels is often knowledge-driven and scale-comparability is solely assessed based on final product quality which does not account for the dynamics of the reaction. In addition, information about the influence of process parameters, such as stirrer speed, temperature, or payload addition rates, is limited due to high material costs. Given these limitations, there is a need for a modeling-based approach to investigate conjugation scale-up. In this work, both experimental kinetic studies and computational fluid dynamics (CFD) conjugation simulations were performed to understand the influence of scale and mixing parameters. In the experimental part, conjugation kinetics in small-scale reaction tubes with different mixing types were investigated for two ADC systems and compared to larger bench-scale reactions. It was demonstrated that more robust kinetics can be achieved through internal stirrer mixing instead of external mixing devices, such as orbital shakers. In the simulation part, 3D-reactor models were created by coupling CFD-models for three large-scale reaction vessels with a kinetic model for a site-specific conjugation reaction. This enabled to study the kinetics in different vessels, as well as the effect of process parameter variations in silico. Overall, it was found that for this conjugation type sufficient mixing can be achieved at all scales and the studied parameters cause only deviations during the payload addition period. An additional time-scale analysis demonstrated to aid the assessment of mixing effects during ADC process scale-up when mixing times and kinetic rates are known. In summary, this work highlights the benefit of kinetic models for enhanced conjugation process understanding without the need for large-scale experiments.

Knockdown of LMNB1 Inhibits the Proliferation of Lung Adenocarcinoma Cells by Inducing DNA Damage and Cell Senescence

Background

Lung cancer has considerably high mortality and morbidity rate. Lung adenocarcinoma (LUAD) tissues highly express lamin B1 (LMNB1), compared with normal tissues. In this study, we knocked down LMNB1 in LUAD cells A549 and NCI-1299 to explore the effect of its inhibition on the proliferation of cells and the potential mechanism.

Methods

Using bioinformatics methods, we analyzed the specificity of LMNB1 mRNA expression level in LUAD and its effect on prognosis from TCGA data. SiRNAs were used to knock down LMNB1 in the A549 cell line, and the knockdown effect was identified by western blotting and qRT-PCR. Through CCK8 cell proliferation assay, wound healing assay, TRAP, cloning formation Assay, DNase I-TUNEL assay, ATAC-seq, immunofluorescence, FISH, in vivo mouse xenograft studies, etc, we evaluated the influence and mechanism of LMNB1 on LUAD cell line proliferation in vitro and in vivo.

Results

According to bioinformatics analysis, LMNB1 is substantially abundant in LUAD tissues and is associated with tumor stage and patient survival (P < 0.05). After silencing LMNB1, the rate of cell growth, wound healing, the number of transwells, and the number of cell colonies all decreased significantly (P < 0.01). With the decreased LMNB1 expression, H3K9me3 protein expression decreases, chromosome accessibility increases, P53, P21, P16 and γ-H2AX protein expression increases, and the number of senescence staining positive cells increases. At the same time, in vivo mouse xenograft experiments showed that the tumor volume of the LMNB1-silenced group was significantly reduced, compared to that of the control group (P < 0.01), and the proliferation biomarker Ki-67 level (P < 0.01) was considerably reduced.

Conclusions

Overexpression of LMNB1 in LUAD cells is significant, which has excellent potential to be an indicator for evaluating the clinical prognosis of LUAD patients and a target for precise treatment.

Development of Novel CD47-Specific ADCs Possessing High Potency Against Non-Small Cell Lung Cancer in vitro and in vivo

Targeted therapies hold promise for efficiently and accurately delivering cytotoxic drugs directly to tumor tissue to exert anticancer effects. CD47 is a membrane protein expressed in a variety of malignant tumors and hematopoietic cells, which plays a key role in immune escape and tumor progression. Although CD47 immunocheckpoint therapy has been developed in recent years, many patients cannot benefit from it because of its low efficiency. To strengthen and extend the therapeutic efficacy of anti-CD47 monoclonal antibody (mAb), we used the newly developed 7DC2 and 7DC4 mAbs as the targeting payload adaptor and VCMMAE as the toxin payload to construct novel CD47-specific immunotoxin (7DC-VCMMAE) by engineering cysteine residues. These CD47-specific ADCs have the better cell penetration, excellent DAR, similar payload distribution and good antigen-binding affinity. In vitro, 7DC-VCMMAE treatment induced death of non-small cell lung cancer (NSCLC) cell lines 95D and SPC-A1, but not A549 that express low levels of CD47 on the cell membrane. This finding suggests that 7DC-VCMMAE may possess greater therapeutic effect on NSCLC tumors expressing a high level of CD47 antigen; however, 7DC-VCMMAE treatment also promoted phagocytosis of A549 cells by macrophages. In vivo, 7DC-VCMMAE treatment had remarkable antitumor effects in a NSCLC cell line-derived xenograft (CDX) mouse model based on nonobese diabetic/severe combined immunodeficient (NOD/SCID). In summary, this study combined VCMMAE with anti-CD47 mAbs, emphasizing a novel and promising immunotherapy method for direct killing of NSCLC, which provides a valuable new way to meet the needs of the cancer therapy field.

The Use of Antibody-Antibiotic Conjugates to Fight Bacterial Infections

The emergence of antimicrobial resistance (AMR) is rapidly increasing and it is one of the significant twenty-first century’s healthcare challenges. Unfortunately, the development of effective antimicrobial agents is a much slower and complex process compared to the spread of AMR. Consequently, the current options in the treatment of AMR are limited. One of the main alternatives to conventional antibiotics is the use of antibody-antibiotic conjugates (AACs). These innovative bioengineered agents take advantage of the selectivity, favorable pharmacokinetic (PK), and safety of antibodies, allowing the administration of more potent antibiotics with less off-target effects. Although AACs’ development is challenging due to the complexity of the three components, namely, the antibody, the antibiotic, and the linker, some successful examples are currently under clinical studies.

An overview of process development for antibody-drug conjugates produced by chemical conjugation technology

Introduction: We discuss chemical conjugation strategies for antibody-drug conjugates (ADCs) from an industrial perspective and compare three promising chemical conjugation technologies to produce site-specific ADCs.Areas covered: Currently, nine ADCs are commercially approved and all are produced by chemical conjugation technology. However, seven of these ADCs contain a relatively broad drug distribution, potentially limiting their therapeutic indices. In 2019, the first site-specific ADC was launched on the market by Daiichi-Sankyo. This achievement, and an analysis of clinical trials over the last decade, indicates that current industrial interest in the ADC field is shifting toward site-specific conjugation technologies. From an industrial point of view, we aim to provide guidance regarding established conjugation methodologies that have already been applied to scale-up stages. With an emphasis on highly productive, scalable, and synthetic process robustness, conjugation methodologies for ADC production is discussed herein.Expert opinion: All three chemical conjugation technologies described in this review have various advantages and disadvantages, therefore drug developers can utilize these depending on their biological and/or protein targets. The future landscape of the ADC field is also discussed.