Phase 1 multicenter, dose-expansion study of ARX788 as monotherapy in HER2-positive advanced gastric and gastroesophageal junction adenocarcinoma

Discussion on the mechanism of HER2 resistance in esophagogastric junction and gastric cancer in the era of immunotherapy

Human epidermal growth factor receptor 2 (HER2) is a critical biomarker and therapeutic target in gastric/gastroesophageal junction (G/GEJ) cancers, despite the initial success of HER2-targeted therapies, such as trastuzumab, resistance to these drugs has emerged as a major impediment to effective long-term treatment. This review examines the mechanisms of drug resistance in HER2-positive G/GEJ cancer, the primary mechanisms of resistance explored include alterations in the HER2 receptor itself, such as mutations and changes in expression levels, as well as downstream signaling pathways, and interactions with the tumor microenvironment (TME). Furthermore, the review discusses the Novel therapeutic approaches, including the use of antibody-drug conjugates (ADCs) and combination therapies are assessed for their potential to enhance outcomes. By integrating recent research findings and clinical trials, this review aims to provide oncologists and researchers with insights into developing more effective treatments for patients with drug-resistant HER2-positive G/GEJ cancer.

Navigating the future of gastric cancer treatment: a review on the impact of antibody-drug conjugates

Gastric cancer, marked by its high incidence and poor prognosis, demands the urgent development of novel and effective treatment strategies, especially for patients ineligible for surgery or those who have had limited success with chemotherapy, radiotherapy and targeted therapies. Recently, antibody-drug conjugates (ADCs) have become a key area of investigation due to their high specificity and potent antitumor effects. These therapies combine monoclonal antibodies, designed to bind to tumor-specific antigens, with cytotoxic agents that selectively target and destroy malignant cells. ADCs have generated significant interest in clinical trials as a promising approach to improve both treatment efficacy and patient outcomes in gastric cancer. However, their clinical application is not without challenges and limitations that must be addressed. This review discusses the recent progress in the use of ADCs for gastric cancer treatment.

The novel BCL-2/BCL-XL inhibitor APG-1252-mediated cleavage of GSDME enhances the antitumor efficacy of HER2-targeted therapy in HER2-positive gastric cancer

HER2-positive gastric cancer has a poor prognosis, with a high incidence of drug resistance and a lack of effective treatments for drug-resistant patients. The exploration of the mechanism of resistance to HER2-targeted therapy in HER2-positive gastric cancer and the identification of effective strategies to reverse it are urgently needed. In this study, we found that HER2-targeted agents upregulated the expression of GSDME and that the overexpression of GSDME attenuated the sensitivity of HER2-targeted agents. Furthermore, we observed that the BCL-2/BCL-XL inhibitor APG-1252 plus lapatinib promoted GSDME-mediated pyroptosis and exhibited remarkable antitumor activity both in vitro and in vivo. Mechanistically, APG-1252 combined with lapatinib synergistically induced GSDME-mediated pyroptosis in HER2-positive gastric cancer by activating caspase-dependent pathways and blocking the phospho-AKT/GSK-3β/MCL-1 signaling pathway. Our data indicated that the combination of lapatinib and APG-1252 had a synergistic antitumor effect on HER2-positive gastric cancer through the induction of caspase-3/GSDME-mediated apoptosis and pyroptosis.

Toxicities and management strategies of emerging antibody-drug conjugates in breast cancer

Antibody-drug conjugates (ADCs) offer a promising therapeutic approach for various cancers, enhancing the therapeutic window while mitigating systemic adverse effects on healthy tissues. ADCs have achieved remarkable clinical success, particularly in treating breast cancer, becoming a standard therapy across all subtypes, including hormone receptor-positive, human epidermal growth factor receptor 2-positive, and triple-negative breast cancer. Although designed to selectively target antigens via monoclonal antibodies, ADCs can exhibit toxicity in normal tissues, often due to off-target effects of their cytotoxic payloads. Understanding and managing these toxicities according to established guidelines are crucial for enhancing ADC clinical efficacy, minimizing adverse events, and ultimately improving patient outcomes. This review comprehensively examines the toxicities of ADCs employed in breast cancer treatment and explores their management strategies. Furthermore, we investigate novel ADCs beyond trastuzumab deruxtecan and sacituzumab govitecan, evaluating their potential efficacy and corresponding safety profiles.

Targeting HER2 in Gastroesophageal Cancer: A New Appetite for an Old Plight

The incidence of gastroesophageal cancers is rising, driven, in part, by an increasing burden of risk factors of obesity and gastroesophageal reflux. Despite efforts to address these risk factors, and a growing interest in methods of population screening, the bulk of these tumours are unresectable at diagnosis. In this setting, effective systemic treatments are paramount to improve survival and quality of life. Early and accurate identification of oncogenic drivers, such as human epidermal growth factor receptor 2 (HER2), present in 5-30% of gastroesophageal adenocarcinomas (GEAs), is integral to guide choice of therapies due to the clear predictive implications that arise from overexpression of this receptor. After trastuzumab, the first anti-HER2 agent with approved use in HER2-positive GEA, the addition of pembrolizumab to first-line trastuzumab-chemotherapy and trastuzumab deruxtecan in the refractory space have more recently changed practice. Yet, the response to these agents has been vastly different across patients with HER2-positive disease, underpinning the need for reliable biomarkers of response. Emergent data have suggested that levels of HER2 expression on tissue or liquid biopsies may predict response to first-generation HER2 therapies while HER2 heterogeneity, receptor changes, co-occurring molecular alterations and oncogenic genomic and metabolic reprogramming may be implicated in resistance. A robust knowledge of the mechanisms of resistance and response to HER2-directed therapies is necessary to inform novel strategies of HER2-targeting and guide choice combinations with other biomarker-directed therapies, to improve outcomes from a new generation of clinical trials in HER2-positive GEA. Understanding and close examination of previous failures in this space form an important part of this assessment, as does correlative biomarker and translational work pertaining to the role of HER2 and dynamic changes that result through treatment exposure. In this review, we aim to provide an overview of strategies for HER2 targeting, summarising both the successes and disappointments in this therapeutic landscape and discuss existing challenges and future perspectives on development in this highly morbid tumour type.

Strategies to Expand the Genetic Code of Mammalian Cells

Genetic code expansion (GCE) in mammalian cells has emerged as a powerful technology for investigating and engineering protein function. This method allows for the precise incorporation of a rapidly growing toolbox of noncanonical amino acids (ncAAs) into predefined sites of target proteins expressed in living cells. Due to the minimal size of these genetically encoded ncAAs, the wide range of functionalities they provide, and the ability to introduce them freely at virtually any site of any protein by simple mutagenesis, this technology holds immense potential for probing the complex biology of mammalian cells and engineering next-generation biotherapeutics. In this review, we provide an overview of the underlying machinery that enables ncAA mutagenesis in mammalian cells and how these are developed. We have also compiled an updated list of ncAAs that have been successfully incorporated into proteins in mammalian cells. Finally, we provide our perspectives on the current challenges that need to be addressed to fully harness the potential of this technology.

The development and evaluation of a tublysine-based antibody-drug conjugate with enhanced tumor therapeutic efficacy

Antibody-drug conjugates (ADCs) offer targeted cancer therapy by delivering cytotoxic agents directly to tumor cells. However, challenges such as relapse, resistance, and diverse patient needs drive ongoing innovation in ADC development. Exploration of new small-molecule toxins with unique antitumor and toxicity profiles is crucial. Tub114, a novel Tubulysin B analog with a hydrophilic ethylene glycol moiety, has been conjugated to the anti-HER2 antibody DX-CHO9, forming the ADC DX126-262. This study examines the efficacy, pharmacokinetics, and safety profile of DX126-262, with a focus on Tubulysin-associated liver toxicity. In vivo efficacy was assessed using three HER2-positive tumor models, with dose-dependent tumor growth inhibition compared to established treatments. Pharmacokinetic studies were conducted in cynomolgus monkeys across a dosing range (3-30 mg/kg) to compare clearance and stability with Kadcyla and Enhertu. Acute toxicity assays were conducted in mice (75 and 150 mg/kg doses), and repeated-dose toxicity was evaluated over five doses, administered every 3 weeks in rats and cynomolgus monkeys. DX126-262 demonstrated significant and dose-dependent tumor growth inhibition across HER2-positive models, with superior antitumor efficacy compared to Kadcyla and comparable efficacy to Enhertu in vivo studies. In pharmacokinetic studies, DX126-262 exhibited a clearance rate similar to Enhertu and enhanced stability compared to Kadcyla. Acute toxicity assays revealed reduced hepatotoxicity at doses of 75 and 150 mg/kg in mice, with improved tolerance. In repeated-dose toxicity studies, DX126-262 was well tolerated in rats at doses up to 200 mg/kg, with the highest non-severely toxic dose (HNSTD) established at 100 mg/kg. In cynomolgus monkeys, DX126-262 demonstrated superior hepatotoxic tolerability without significant bone marrow suppression, with an HNSTD of 30 mg/kg. DX126-262, incorporating Tub114, a novel Tubulysin B analog, effectively mitigates the inherent hepatotoxicity associated with Tubulysin compounds while maintaining strong antitumor efficacy. These findings suggest that DX126-262 could serve as a safer and more effective option for HER2-targeted cancer therapy, warranting further clinical studies to confirm its therapeutic potential.

Human Epidermal Growth Factor Receptor 2 Positive Advanced Gastric or Esophagogastric Adenocarcinoma: Reflecting on the Past to Gain a New Insights

PURPOSE OF REVIEW

Human epidermal growth factor receptor 2 (HER2) is a critical target in advanced gastric cancer (AGC). This review highlights the current treatment landscape, lessons learned from past clinical trials, and prospects for future treatment strategies for HER2-positive AGC.

RECENT FINDINGS

Trastuzumab had been the standard treatment for HER2-positive AGC for a decade, and subsequently, trastuzumab deruxtecan, an antibody-drug conjugate (ADC), emerged with an impressive response. Recently, the addition of pembrolizumab to first-line chemotherapy plus trastuzumab has become a novel standard treatment. Past clinical trials of HER2-targeted therapies, which succeeded in HER2-positive breast cancer but failed in AGC, have deepened our understanding of resistance mechanisms. Based on these results, several clinical trials of novel HER2-targeted therapies, including immunologic approaches such as CAR-T cells and vaccines, are currently ongoing. Circulating tumor DNA is also expected to be a tool for real-time biomarker analysis. Additionally, ADCs with a bystander effect have the potential to expand the scope of HER2-targeted therapies to HER2-expressing, including HER2-low AGC. Learning from past trials, further development of novel HER2-targeted therapies is underway, expanding their scope to HER2-expressing AGC. Meanwhile, selecting optimal treatment is a challenging issue in cases with HER2-low AGC overlapping with other biomarkers like CLDN18.2.

Perioperative Treatment in Gastric Cancer: A Fast-Changing Field

Gastric cancer is the fifth most common cancer worldwide and its incidence is rising. Surgery is the only curative strategy and its association with perioperative chemotherapy is now standard treatment for most resectable tumors. Despite treatment advances, disease relapse is high, even in early stages, and continued improvement in curative treatment is imperative. With deeper knowledge of gastric cancer heterogeneity, molecular subtypes, and the tumor immune microenvironment, new standard treatment strategies may emerge in the near future. This paper provides a comprehensive review of the current treatment landscape in resectable gastric cancer and future perspectives for the next decade regarding new agents such as targeted therapies, immunotherapy, antibody-drug conjugates, and the combination of multiple treatment modalities.

Unveiling the future of breast cancer therapy: Cutting-edge antibody-drug conjugate strategies and clinical outcomes

Breast cancer has become the most prevalent malignant tumor worldwide and remains one of the leading causes of cancer-related mortality among women globally. The prognosis for patients with metastatic breast cancer remains poor, necessitating the exploration of novel therapeutic strategies to improve survival rates. In the era of precision medicine, antibody-drug conjugates (ADCs) have gained significant attention as a targeted therapeutic strategy in breast cancer treatment. ADCs, a relatively new treatment for breast cancer, deliver cytotoxic drugs (payloads), directly into the tumor space, turning chemotherapy into a targeted agent, which enables patients to experience significant improvements with manageable drug toxicity. For the treatment of breast cancer, there are three ADCs approved for breast cancer treatment: Trastuzumab emtansine (T-DM1), Trastuzumab Deruxtecan (T-Dxd) targeting HER-2, and Sacituzumab Govitecan (SG) targeting Trop-2. Recent clinical studies have demonstrated that the benefits of ADC therapies extend beyond HER2-positive breast cancer toinclude hormone receptor (HR)-positive breast cancer, triple-negative breast cancer (TNBC), and HER2-low expressing breast cancer. Notably, the DESTINY-Breast series of studies, particularly focusing on T-Dxd, encompass neoadjuvant, adjuvant, and multiple lines of therapy for advanced breast cancer. This marks the advent of a comprehensive ADC era in breast cancer treatment. This review summarizes the efficacy and adverse effects of ADC therapies that have completed or are currently undergoing phase I-III clinical trials. Additionally, it analyzes potential combination strategies to overcome ADC resistance, aiming to provide clinicians with a comprehensive clinical guide to the use of ADCs in breast cancer treatment.

A novel anti-HER2 monoclonal antibody IAH0968 in HER2-positive heavily pretreated solid tumors: results from a phase Ia/Ib first-in-human, open-label, single center study

Background

IAH0968 is an afucosylated anti-epidermal growth factor receptor 2 (HER2) monoclonal antibody which improved the activity of antibody-dependent cellular cytotoxicity (ADCC) and superior anti-tumor efficacy.

Methods

To determine the maximum tolerated dose (MTD) with dose-limiting toxicity (DLT), a single institution, phase Ia/Ib study was undertaken, using 3 + 3 design. The primary endpoints were safety, tolerability and preliminary clinical activity. Eighteen patients were evaluable for safety and fifteen patients were suitable for efficacy analysis. Dose escalations were 6 mg/kg (N = 2), 10 mg/kg (N = 7), 15 mg/kg (N = 5), and tolerable up to 20 mg/kg (N = 4).

Results

Only one DLT was found at dosage 10 mg/kg, and no MTD was reached. The most common Grade 3 treatment-related adverse events (TRAEs) were hypokalemia (5.6%), supraventricular tachycardia (5.6%), interval extension of QTC (5.6%), and infusion reaction (5.6%). Grade 4 TRAE was arrhythmia (5.6%). No serious TRAE or Grade 5 was reported. 22.2% of patients had a TRAE leading to dose adjustment and 16.7% of patients had a TRAE resulting in discontinuation of IAH0968. After a median follow-up of 9.7 months (range, 3.7 - 22.0), the objective response rate (ORR) was 13.3% (2/15), the disease control rate (DCR) was 53.3% (8/15), and median progression-free survival (mPFS) was 4.2 months (95% CI: 1.4 - 7.7), and the median duration of disease control (DDC) was 6.3 months (95% CI: 2.9-not reached), with 4/15 responses ongoing.

Conclusions

In HER2-positive heavily pretreated metastatic patients, IAH0968 demonstrated promising clinical activity with durable responses and tolerable safety profiles.

Clinical trial registration

ClinicalTrials.gov, identifier NCT04934514.

Targeting esophageal carcinoma: molecular mechanisms and clinical studies

Esophageal cancer (EC) is identified as a predominant health threat worldwide, with its highest incidence and mortality rates reported in China. The complex molecular mechanisms underlying EC, coupled with the differential incidence of esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC) across various regions, highlight the necessity for in-depth research targeting molecular pathogenesis and innovative treatment strategies. Despite recent progress in targeted therapy and immunotherapy, challenges such as drug resistance and the lack of effective biomarkers for patient selection persist, impeding the optimization of therapeutic outcomes. Our review delves into the molecular pathology of EC, emphasizing genetic and epigenetic alterations, aberrant signaling pathways, tumor microenvironment factors, and the mechanisms of metastasis and immune evasion. We further scrutinize the current landscape of targeted therapies, including the roles of EGFR, HER2, and VEGFR, alongside the transformative impact of ICIs. The discussion extends to evaluating combination therapies, spotlighting the synergy between targeted and immune-mediated treatments, and introduces the burgeoning domain of antibody-drug conjugates, bispecific antibodies, and multitarget-directed ligands. This review lies in its holistic synthesis of EC's molecular underpinnings and therapeutic interventions, fused with an outlook on future directions including overcoming resistance mechanisms, biomarker discovery, and the potential of novel drug formulations.

Advances in HER2-Targeted Therapies: From monoclonal antibodies to dual inhibitors developments in cancer treatment

HER2 receptors, overexpressed in certain human cancers, have drawn significant attention in cancer research due to their correlation with poor survival rates. Researchers have developed monoclonal antibodies like Trastuzumab and Pertuzumab against HER2 receptors, which have proven highly beneficial in cancer therapy. Bispecific antibodies like Zanidatamab and antibody-drug conjugates like T-DM1 have been developed to overcome the resistance associated with monotherapy. Small molecules such as Lapatinib, Neratinib, and Pyrotinib were initially developed for treating breast cancer. However, ongoing research is investigating their potential use in other types of cancer, often in combination with other medications. EGFR/HER2 dual-targeted drugs have overcome drug resistance associated with HER2-targeted monotherapy. This comprehensive review covers the structural characteristics of HER2, the HER family signaling pathway mechanism, recent findings regarding HER2 receptor involvement in various cancers, and diverse HER2-targeted therapies. This information provides a comprehensive understanding of HER2-targeted strategies in the evolving field of cancer treatment.

Synthesis at the Interface of Chemistry and Biology

Chemical synthesis as a tool to control the structure and properties of matter is at the heart of chemistry─from the synthesis of fine chemicals and polymers to drugs and solid-state materials. But as the field evolves to tackle larger and larger molecules and molecular complexes, the traditional tools of synthetic chemistry become limiting. In contrast, Mother Nature has developed very different strategies to create the macromolecules and molecular systems that make up the living cell. Our focus has been to ask whether we can use the synthetic strategies and machinery of Mother Nature, together with modern chemical tools, to create new macromolecules, and even whole organisms with properties not existing in nature. One such example involves reprogramming the complex, multicomponent machinery of ribosomal protein synthesis to add new building blocks to the genetic code, overcoming a billion-year constraint on the chemical nature of proteins. This methodology exploits the concept of bioorthogonality to add unique codons, tRNAs and aminoacyl-tRNA synthetases to cells to encode amino acids with physical, chemical and biological properties not found in nature. As a result, we can make precise changes to the structures of proteins, much like those made by chemists to small molecules and beyond those possible by biological approaches alone. This technology has made it possible to probe protein structure and function in vitro and in vivo in ways heretofore not possible, and to make therapeutic proteins with enhanced pharmacology. A second example involves exploiting the molecular diversity of the humoral immune system together with synthetic transition state analogues to make catalytic antibodies, and then expanding this diversity-based strategy (new to chemists at the time) to drug discovery and materials science. This work ushered in a new nature-inspired synthetic strategy in which large libraries of natural or synthetic molecules are designed and then rationally selected or screened for new function, increasing the efficiency by which we can explore chemical space for new physical, chemical and biological properties. A final example is the use of large chemical libraries, robotics and high throughput phenotypic cellular screens to identify small synthetic molecules that can be used to probe and manipulate the complex biology of the cell, exemplified by druglike molecules that control cell fate. This approach provides new insights into complex biology that complements genomic approaches and can lead to new drugs that act by novel mechanisms of action, for example to selectively regenerate tissues. These and other advances have been made possible by using our knowledge of molecular structure and reactivity hand in hand with our understanding of and ability to manipulate the complex machinery of living cells, opening a new frontier in synthesis. This Account overviews the work in my lab and with our collaborators, from our early days to the present, that revolves around this central theme.

Antibody-drug conjugates in gastric cancer: from molecular landscape to clinical strategies

Antibody-drug conjugates (ADCs) represent a crucial component of targeted therapies in gastric cancer, potentially altering traditional treatment paradigms. Many ADCs have entered rigorous clinical trials based on biological theories and preclinical experiments. Modality trials have also been conducted in combination with monoclonal antibody therapies, chemotherapies, immunotherapies, and other treatments to enhance the efficacy of drug coordination effects. However, ADCs exhibit limitations in treating gastric cancer, including resistance triggered by their structure or other factors. Ongoing intensive researches and preclinical experiments are yielding improvements, while enhancements in drug development processes and concomitant diagnostics during the therapeutic period actively boost ADC efficacy. The optimal treatment strategy for gastric cancer patients is continually evolving. This review summarizes the clinical progress of ADCs in treating gastric cancer, analyzes the mechanisms of ADC combination therapies, discusses resistance patterns, and offers a promising outlook for future applications in ADC drug development and companion diagnostics.

Clinical best practices in interdisciplinary management of human epidermal growth factor receptor 2 antibody-drug conjugates-induced interstitial lung disease/pneumonitis: An expert consensus in China

Antibody-drug conjugates (ADCs) have demonstrated effectiveness in treating various cancers, particularly exhibiting specificity in targeting human epidermal growth factor receptor 2 (HER2)-positive breast cancer. Recent advancements in phase 3 clinical trials have broadened current understanding of ADCs, especially trastuzumab deruxtecan, in treating other HER2-expressing malignancies. This expansion of knowledge has led to the US Food and Drug Administration's approval of trastuzumab deruxtecan for HER2-positive and HER2-low breast cancer, HER2-positive gastric cancer, and HER2-mutant nonsmall cell lung cancer. Concurrent with the increasing use of ADCs in oncology, there is growing concern among health care professionals regarding the rise in the incidence of interstitial lung disease or pneumonitis (ILD/p), which is associated with anti-HER2 ADC therapy. Studies on anti-HER2 ADCs have reported varying ILD/p mortality rates. Consequently, it is crucial to establish guidelines for the diagnosis and management of ILD/p in patients receiving anti-HER2 ADC therapy. To this end, a panel of Chinese experts was convened to formulate a strategic approach for the identification and management of ILD/p in patients treated with anti-HER2 ADC therapy. This report presents the expert panel's opinions and recommendations, which are intended to guide the management of ILD/p induced by anti-HER2 ADC therapy in clinical practice.

State-of-the-Art Advancements in Gastroesophageal Cancer Treatment: Harnessing Biomarkers for Precision Care

Gastroesophageal cancers (GECs) represent a significant clinical challenge. For early resectable GEC, the integration of immune checkpoint inhibitors into the perioperative chemotherapy and chemoradiation treatment paradigms are being explored and showing promising results. Frontline management of metastatic GEC is exploring the role of targeted therapies beyond PD-1 inhibitors, including anti-human epidermal growth factor receptor 2 agents, Claudin 18.2 inhibitors, and FGFR2 inhibitors, which have shown considerable efficacy in recent trials. Looking ahead, ongoing trials and emerging technologies such as bispecific antibodies, antibody-drug conjugates, and adoptive cell therapies like chimeric antigen receptor T cells are expected to define the future of GEC management. These advancements signify a paradigm shift toward personalized and immunotherapy-based approaches, offering the potential for improved outcomes and reduced toxicity for patients with GEC.

HER2+ advanced gastric cancer: Current state and opportunities (Review)

Human epidermal growth factor receptor 2 (HER2)+ gastric cancer (GC) is a distinct subtype of GC, accounting for 10‑20% of all cases of GC. Although the development of the anti‑HER2 monoclonal antibody trastuzumab has markedly improved response rates and prognosis of patients with HER2+ advanced GC (AGC), drug resistance remains a considerable challenge. Therefore, dynamic monitoring of HER2 expression levels can facilitate the identification of patients who may benefit from targeted therapy. Besides trastuzumab, DS‑8201 and RC48 have been applied in the treatment of HER2+ AGC, and several novel anti‑HER2 therapies are undergoing preclinical/clinical trials. At present, combination immunotherapy with anti‑HER2 agents is used as the first‑line treatment of this disease subtype. New promising approaches such as chimeric antigen receptor T‑cell immunotherapy and cancer vaccines are also being investigated for their potential to improve clinical outcomes. The current review provides new insights that will guide the future application of anti‑HER2 therapy by summarizing research progress on targeted therapy drugs for HER2+ AGC and combination treatments.

Next-Generation HER2-Targeted Antibody-Drug Conjugates in Breast Cancer

Human epidermal growth factor receptor 2 (HER2) tyrosine kinase is overexpressed in 20% of breast cancers and associated with a less favorable prognosis compared to HER2-negative disease. Patients have traditionally been treated with a combination of chemotherapy and HER2-targeted monoclonal antibodies such as trastuzumab and pertuzumab. The HER2-targeted antibody-drug conjugates (ADCs) trastuzumab emtansine (T-DM1) and trastuzumab deruxtecan (T-DXd) represent a novel class of therapeutics in breast cancer. These drugs augment monoclonal antibodies with a cytotoxic payload, which is attached by a linker, forming the basic structure of an ADC. Novel combinations and sequential approaches are under investigation to overcome resistance to T-DM1 and T-DXd. Furthermore, the landscape of HER2-targeted therapy is rapidly advancing with the development of ADCs designed to attack cancer cells with greater precision and reduced toxicity. This review provides an updated summary of the current state of HER2-targeted ADCs as well as a detailed review of investigational agents on the horizon. Clinical trials are crucial in determining the optimal dosing regimens, understanding resistance mechanisms, and identifying patient populations that would derive the most benefit from these treatments. These novel ADCs are at the forefront of a new era in targeted cancer therapy, holding the potential to improve outcomes for patients with HER2-positive and HER2-Low breast cancer.

Oxime-Linked Peptide-Daunomycin Conjugates as Good Tools for Selection of Suitable Homing Devices in Targeted Tumor Therapy: An Overview

Chemotherapy is still one of the main therapeutic approaches in cancer therapy. Nevertheless, its poor selectivity causes severe toxic side effects that, together with the development of drug resistance in tumor cells, results in a limitation for its application. Tumor-targeted drug delivery is a possible choice to overcome these drawbacks. As well as monoclonal antibodies, peptides are promising targeting moieties for drug delivery. However, the development of peptide-drug conjugates (PDCs) is still a big challenge. The main reason is that the conjugates have to be stable in circulation, but the drug or its active metabolite should be released efficiently in the tumor cells. For this purpose, suitable linker systems are needed that connect the drug molecule with the homing peptide. The applied linker systems are commonly categorized as cleavable and non-cleavable linkers. Both the groups possess advantages and disadvantages that are summarized briefly in this manuscript. Moreover, in this review paper, we highlight the benefit of oxime-linked anthracycline-peptide conjugates in the development of PDCs. For instance, straightforward synthesis as well as a conjugation reaction proceed in excellent yields, and the autofluorescence of anthracyclines provides a good tool to select the appropriate homing peptides. Furthermore, we demonstrate that these conjugates can be used properly in in vivo studies. The results indicate that the oxime-linked PDCs are potential candidates for targeted tumor therapy.

Human Epidermal Growth Factor Receptor-2 Gastric Adenocarcinoma: Expanding Therapy of a Recognized Target

Human epidermal growth factor receptor-2 (HER2) is a well-known cancer target. Many HER2-targeted agents are marketed and being investigated. Unfortunately, these therapies lack consistent responses and outcomes amongst different tumors. Questions remain as to why HER2 biology is different in different tumor types. Gastric adenocarcinomas (GACs) demonstrate both intra- and inter-tumor HER2 expression heterogeneity and show discordance amongst primary and metastatic disease sites. This creates barriers in determining HER2 agents' effectiveness and contributes to the failure of some HER2-targeted agents in the treatment of HER2-positive advanced GACs. Trastuzumab deruxtecan, an antibody drug conjugate of trastuzumab with a topoisomerase inhibitor, was recently approved for the treatment of refractory HER2-positive advanced GAC patients. There are exciting and newer therapies under investigation. Examining resistance patterns (both adaptive and acquired) along with establishing a better understanding of the intra- and inter-tumor heterogeneity is necessary to ensure successful progress. Here we review the current status of HER2-targeted therapy in GACs. We additionally review newer therapies under investigation and their potential role in HER2 GACs.

The History and Development of HER2 Inhibitors

HER2 is highly expressed in a variety of malignant tumors and affects the prognosis of patients, making it a highly sensitive target for cancer therapy. Since the approval of the first HER2 inhibitor, trastuzumab, in 1998, HER2-targeted drugs have rapidly evolved. Currently, targeting HER2 drugs mainly include monoclonal antibodies (mAbs), tyrosine kinase inhibitors (TKIs), and antibody-drug conjugates (ADCs). This article reviews the development of HER2 inhibitors for various tumors over the past 20 years.

Analytical comparability to evaluate impact of manufacturing changes of ARX788, an Anti-HER2 ADC in late-stage clinical development

ARX788 is an anti-HER2 antibody drug conjugate (ADC) developed using Ambrx proprietary Engineered Precision Biologics technology. The manufacturing process of ARX788 has been optimized during the course of early to late-phase clinical development. A comprehensive evaluation of side-by-side comparability between pre- and post-change process for ARX788 drug substance and drug product from a quality perspective was conducted based on ICH Q5E guidelines consisting of batch release assays, physicochemical and biophysical characterization, biological characterization, and forced degradation studies. All results have substantiated a high degree of similarity between the pre- and post-change ARX788 drug substance batches and drug product lots, demonstrating that the process manufacturing changes did not impact product quality.

Gastric cancer treatment: recent progress and future perspectives

Gastric cancer (GC) is one of the most common malignancies worldwide. Most patients are diagnosed at advanced stages due to the subtle symptoms of earlier disease and the low rate of regular screening. Systemic therapies for GC, including chemotherapy, targeted therapy and immunotherapy, have evolved significantly in the past few years. For resectable GC, perioperative chemotherapy has become the standard treatment. Ongoing investigations are exploring the potential benefits of targeted therapy or immunotherapy in the perioperative or adjuvant setting. For metastatic disease, there have been notable advancements in immunotherapy and biomarker-directed therapies recently. Classification based on molecular biomarkers, such as programmed cell death ligand 1 (PD-L1), microsatellite instability (MSI), and human epidermal growth factor receptor 2 (HER2), provides an opportunity to differentiate patients who may benefit from immunotherapy or targeted therapy. Molecular diagnostic techniques have facilitated the characterization of GC genetic profiles and the identification of new potential molecular targets. This review systematically summarizes the main research progress in systemic treatment for GC, discusses current individualized strategies and presents future perspectives.

Antibody-drug conjugates: the clinical development in gastric cancer

Gastric cancer (GC) is a prevalent malignant tumor of the digestive system worldwide, ranking among the top five in terms of incidence and mortality. However, the clinical efficacy of conventional treatments for gastric cancer remains limited, with a median overall survival of approximately eight months for advanced cases. In recent years, researchers have increasingly focused on antibody-drug conjugates (ADCs) as a promising approach. ADCs are potent chemical drugs that selectively target cancer cells by binding to specific cell surface receptors with antibodies. Notably, ADCs have demonstrated promising results in clinical studies and have made significant strides in the treatment of gastric cancer. Currently, several ADCs are under investigation in clinical trials for gastric cancer patients, targeting various receptors such as EGFR, HER-2, HER-3, CLDN18.2, Mucin 1, among others. This review offers a comprehensive exploration of ADC drug characteristics and provides an overview of the research progress in ADC-based therapies for gastric cancer.