Open-label, Multicenter, Phase II Study of RC48-ADC, a HER2-Targeting Antibody-Drug Conjugate, in Patients with Locally Advanced or Metastatic Urothelial Carcinoma

Clinicopathological significance of the overexpression of MUC1 in upper tract urothelial carcinoma and possible application as a diagnostic marker

Mucin 1 (MUC1) overexpression has been reported in many malignancies and is associated with a poor prognosis. However, the clinicopathological significance of MUC1 in upper tract urothelial carcinoma (UTUC) has not been investigated. We analyzed the expression and distribution of MUC1 in UTUC by immunohistochemistry. In normal urothelium, MUC1 expression was observed on the surface of umbrella cells. Meanwhile, the strong expression of MUC1 was observed in cell membranes and cytoplasm in UTUC tissues, and it was detected in 64 (58%) of a total of 110 UTUC cases. MUC1-positive UTUC cases were associated with nodular/flat morphology, high grade, high T stage, and lymphatic and venous invasion and poor prognosis. Additionally, MUC1 expression was associated with high expression of Ki-67, programmed death-ligand 1 (PD-L1), CD44 variant 9 (CD44v9), human epidermal growth factor receptor 2 (HER2), epidermal growth factor receptor (EGFR), and p53 in UTUC. Furthermore, immunocytochemistry for MUC1 on urine cytology slides demonstrated that the strong staining of MUC1 was more frequently found in tumor cells than in nonneoplastic cells. The diagnostic accuracy of urine cytology was improved by combining MUC1 immunostaining with cytology. These results suggest that MUC1 may be a prognostic biomarker in UTUC, and MUC1 exression has a potential application as a diagnostic immunomarker for urine cytology.

State-of-the-Art Advances of Nanomedicine for Diagnosis and Treatment of Bladder Cancer

Bladder cancer is a common malignant tumor of the urinary system. Cystoscopy, urine cytology, and CT are the routine diagnostic methods. However, there are some problems such as low sensitivity and difficulty in staging, which must be urgently supplemented by novel diagnostic methods. Surgery, intravesical instillation, systemic chemotherapy, and radiotherapy are the main clinical treatments for bladder cancer. It is difficult for conventional treatment to deal with tumor recurrence, progression and drug resistance. In addition, the treatment agents usually have the defects of poor specific distribution ability to target tumor tissues and side effects. The rapid development of nanomedicine has brought hope for the treatment of bladder cancer in reducing side effects, enhancing tumor inhibition effects, and anti-drug resistance. Overall, we review the new progression of nano-platforms in the diagnosis and treatment of bladder cancer.

Novel treatment approaches for HER2 positive solid tumors (excluding breast cancer)

PURPOSE OF REVIEW

Human epidermal growth factor 2 (HER2) alterations (protein overexpression, gene amplification and mutation) play a key role in oncogenesis and are more likely correlated to poorer outcome in solid tumors. We reviewed recently published studies in the last 18 months on novel treatment approaches for HER2 positive solid tumors (excluding breast cancer).

RECENT FINDINGS

Results of clinical studies assessing anti-HER2 therapies have been recently issued.One of the most promising drugs is transtuzumab deruxtecan, an antibody-drug conjugate which demonstrated clinically meaningful activity in gastric or gastroesophageal junction cancer and colorectal cancers.Small molecules such as poziotinib, pyrotinib, neratinib, which target both epidermal growth factor receptor (EGFR) and HER2 also showed promising activity, especially in heavily pretreated ERRB2-mutated non-small cell lung cancer (NSCLC) cancer patients. Yet, these findings need to be confirmed in confirmatory randomized trials with larger cohorts.Trastuzumab-based combinations with chemotherapy or immune checkpoint inhibitors are under development with promising results, but not in all HER2 tumors. Emerging adverse events with anti-HER2 are interstitial pneumopathy and diarrhea.

SUMMARY

Tyrosine kinase inhibitors, antibody drug conjugate in monotherapy and combinations are emerging strategies in many HER2-positive cancers; HER2 therapies are now part of standard of care of HER2-amplified gastric or gastroesophageal junction cancer. Data are pending on several unmet medical needs.

Efficacy of Disitamab Vedotin in a heavily pre-treated HER2 positive lung adenocarcinoma patient: case report and literature review

Cancer therapies targeting human epidermal growth factor receptor 2 (HER2) have been attracting increasing attention worldwide, especially in lung adenocarcinoma. Disitamab vedotin is an antibody-drug conjugate designed for targeting HER2 that has been approved for urothelial carcinoma and gastric cancer. However, there is still a lack of clinical evidence for applying Disitamab vedotin in lung adenocarcinoma. Herein, we reported a case of a 52-year-old man with advanced lung adenocarcinoma carrying HER2 amplification as well as HER2 immunohistochemistry (IHC) 2 + who underwent treatment with Disitamab vedotin after disease progression. The patient was treated with chemotherapy, anti-angiogenesis therapy, and immunotherapy as first-line therapy, achieving a remarkable progression-free survival of 16 months. After the disease continued to continuous progress, the patient was administrated with Disitamab vedotin, which resulted in improvement of both the lung lesions and the brain lesions. Our findings provide a valuable reference for the utilization of Disitamab Vedotin in HER2 IHC2+ lung adenocarcinoma.

Enfortumab vedotin in the treatment of urothelial cancers and beyond

Enfortumab vedotin (EV) is the first antibody-drug conjugate approved for locally advanced or metastatic urothelial cancers (la/mUCs), a disease group historically associated with limited prognosis and therapeutic options. EV consists of monomethyl auristatin E, a microtubule-disrupting agent linked to an antibody targeting Nectin-4. In clinical trials, EV demonstrated high response rates and superior survival in the third-line setting for la/mUC compared with chemotherapy. Peripheral neuropathy and rash were among the most common serious adverse events. EV is currently approved in multiple countries for the treatment of la/mUC in the later-line setting. Ongoing trials seek to expand the indication for EV and to study therapeutic combinations with other agents.

An update on antibody-drug conjugates in urothelial carcinoma: state of the art strategies and what comes next

In recent years, considerable progress has been made in increasing the knowledge of tumour biology and drug resistance mechanisms in urothelial cancer. Therapeutic strategies have significantly advanced with the introduction of novel approaches such as immune checkpoint inhibitors and Fibroblast Growth Factor Receptor inhibitors. However, despite these novel agents, advanced urothelial cancer is often still progressive in spite of treatment and correlates with a poor prognosis. The introduction of antibody–drug conjugates consisting of a target-specific monoclonal antibody covalently linked to a payload (cytotoxic agent) is a novel and promising therapeutic strategy. In December 2019, the US Food and Drug Administration (FDA) granted accelerated approval to the nectin-4-targeting antibody–drug conjugate, enfortumab vedotin, for the treatment of advanced or metastatic urothelial carcinomas that are refractory to both immune checkpoint inhibitors and platinum-based treatment. Heavily pre-treated urothelial cancer patients reported a significant, 40% response to enfortumab vedotin while other antibody–drug conjugates are currently still under investigation in several clinical trials. We have comprehensively reviewed the available treatment strategies for advanced urothelial carcinoma and outlined the mechanism of action of antibody–drug conjugate agents, their clinical applications, resistance mechanisms and future strategies for urothelial cancer.

The Relationship of Pyroptosis-Related Genes, Patient Outcomes, and Tumor-Infiltrating Cells in Bladder Urothelial Carcinoma (BLCA)

Introduction: The role of pyroptosis and its effects on tumor-infiltrating cells (TICs) in the pathogenesis and treatment outcomes of patients with bladder urothelial carcinoma (BLCA) remains unclear.

Methods: We conducted a bioinformatics analysis on the pyroptosis-related genes (PRGs) and TICs using data from public domains, and evaluated their impact on the pathogenesis and clinical outcomes of BLCA patients. A risk score based on PRGs and a prognostic risk model that incorporated patient demographics, tumor characteristics, and differentially expressed genes (DEGs) were developed.

Results: Twenty-three DEGs of 52 PRGs were identified in BLCA and normal samples from the TCGA database. Missense mutations and single nucleotide polymorphisms in PRGs are the most common genetic abnormalities. Patients with high PRG risk scores showed an inferior survival compared to those with low risk scores. The prognostic risk model based on patient demographics, tumor characteristics, and DEGs showed good predictive values for patient survival at 1, 3, and 5 years in BLCA patients. Caspase-8 (CASP8) was the only intersection gene of the prognostic genes, DEGs, and different genes expressed in tissue. Patients with a high CASP8 expression had improved survival, and an increased CASP8 expression level was observed in activated CD4 memory T cells, follicular T helper cells, resting NK cells, M0 macrophages, and activated dendritic cells. CASP8 expression also showed a positive correlation with the IL7R expression—a key cell marker of CD4 memory T cells. CASP8 expression also showed correlations with immune checkpoints (PDCD1, CD274, and CTLA4) and response to immune checkpoint inhibitors.

Conclusion: Our data suggest that PRGs, especially CASP8, showed strong associations with patient outcomes and TICs in BLCA. If validated, these results could potentially aid in the prognostication and guide treatment in BLCA patients.

Histology-agnostic approvals for antibody-drug conjugates in solid tumours: is the time ripe?

Several antibody-drug conjugates (ADCs) have been recently approved to treat solid tumours. Since ADCs seem to have activity in multiple malignancies sharing the expression of a specific antigen, they may be mirroring the experience of histology-agnostic-targeted treatments. So, the possibility to interpret the activity of some ADCs across different cancer types in a biomarker-driven perspective arises. However, relevant biological, methodological, and regulatory challenges should be highlighted and addressed, in order to grant ADCs biomarker-driven regulatory approvals in the next future. In this review, we discuss challenges and opportunities posed by the pan-histological expansion of ADCs in solid tumours. In particular, we provide an overview about technological and manufacturing advancements; we offer up-to-date highlights of the current evidence from clinical trials investigating ADCs in solid tumours; we discuss the need for the identification of optimal predictive biomarkers, as well as major methodological, statistical, and regulatory considerations for a biomarker-driven histology-agnostic approach.

Expert consensus on the clinical application of antibody-drug conjugates in the treatment of malignant tumors (2021 edition)

Antibody-drug conjugates (ADCs) are targeted biological agents composed of a cytotoxic drug linked to a monoclonal antibody through a linker. The monoclonal antibody targets tumor cells and transports small-molecule cytotoxic drugs for specific delivery and minimal off-target side effects. It is necessary for clinicians to understand the molecular characteristics and mechanisms of ADCs. Patients' survival mainly depends on the appropriate dose and course of treatment and also on proper management of adverse reactions. This consensus provides a systematic review of commercially available ADCs and further discusses the clinical application and management of ADCs.

Identification of New Prognostic Markers and Therapeutic Targets for Non-Muscle Invasive Bladder Cancer: HER2 as a Potential Target Antigen

Bacillus Calmette–Guérin (BCG) is the gold standard adjuvant treatment for non-muscle-invasive bladder cancer (NMIBC). However, given the current global shortage of BCG, new treatments are needed. We evaluated tumor microenvironment markers as potential BCG alternatives for NMIBC treatment. Programmed death-ligand 1, human epidermal growth factor receptor-2 (HER2), programmed cell death-1 (PD1), CD8, and Ki67 levels were measured in treatment-naïve NMIBC and MIBC patients (pTa, pT1, and pT2 stages). Univariate and multivariate Cox proportional hazard models were used to determine the impact of these markers and other clinicopathological factors on survival, recurrence, and progression. EP263, IM142, PD1, and Ki67 levels were the highest in the T2 stage, followed by the T1 and Ta stages. HER2 and IM263 expressions were higher in the T1 and T2 stages than in the Ta stage. In NMIBC, the significant prognostic factors for recurrence-free survival were adjuvant therapy, tumor grade, and HER2 positivity, whereas those for progression-free survival included age, T-stage, and IM263. Age, T-stage, EP263, PD1, CD8, and Ki67 levels were significant factors associated with overall survival. IM263 and HER2 are potential biomarkers for progression and recurrence, respectively. Therefore, we propose HER2 as a potential target antigen for intravesical therapeutics as a BCG alternative.

Current status and future prospects of antibody-drug conjugates in urological malignancies

Antibody-drug conjugates represent a promising new treatment option that uses the targeting ability of an antibody to deliver cytotoxic drugs directly to tumors. Antibody-drug conjugates provide the opportunity to deliver drugs to antigen-expressing cancer cells while minimizing toxicity to normal tissue, achieving wider therapeutic windows. To date, three antibody-drug conjugates have been approved by the US Food and Drug Administration, and many antibody-drug conjugates are under clinical development for urological malignancies. In this paper, we review the mechanism, history, and development of antibody-drug conjugates, and review the current landscape of antibody-drug conjugates in urological malignancies including 12 targets and 18 antibody-drug conjugates in prostate cancer, renal cancer, and urothelial cancer. Furthermore, we review the rational combination of antibody-drug conjugates with immune checkpoint inhibitors and consider future prospects to enhance the therapeutic activity of antibody-drug conjugates in urological malignancies.

Antibody-Drug Conjugates in Uro-Oncology

Currently available treatment options for patients with refractory metastatic prostate, bladder, or kidney cancers are limited with the prognosis remaining poor. Advances in the pathobiology of tumors has led to the discovery of cancer antigens that may be used as the target for cancer treatment. Antibody-drug conjugates (ADCs) are a relatively new concept in cancer treatment that broaden therapeutic landscape. ADCs are examples of a 'drug delivery into the tumor' system composed of an antigen-directed antibody linked to a cytotoxic drug that may release cytotoxic components after binding to the antigen located on the surface of tumor cells. The clinical properties of drugs are influenced by every component of ADCs. Regarding uro-oncology, enfortumab vedotin (EV) and sacituzumab govitecan (SG) are currently registered for patients with locally advanced or metastatic urothelial cancer following previous treatment with an immune checkpoint inhibitor (iCPI; programmed death receptor-1 [PD-1] or programmed death-ligand 1 [PD-L1]) inhibitor) and platinum-containing chemotherapy. The EV-301 trial showed that EV significantly prolonged the overall survival compared with classic chemotherapy. The TROPHY-U-01 trial conducted to evaluate SG demonstrated promising results as regards the objective response rate and duration of response. The safety and efficacy of ADCs in monotherapy and polytherapy (mainly with iCPIs) for different cancer stages and tumor types are assessed in numerous ongoing clinical trials. The aim of this review is to present new molecular biomarkers, specific mechanisms of action, and ongoing clinical trials of ADCs in genitourinary cancers. In the expert discussion, we assess the place of ADCs in uro-oncology and discuss their clinical value.

Head-to-Head Comparison of the Expression Differences of NECTIN-4, TROP-2, and HER2 in Urothelial Carcinoma and Its Histologic Variants

Background

Antibody–drug conjugates (ADC), such as enfortumab vedotin (EV), sacituzumab govitecan (SG), and RC-48, have shown outstanding response rates to local advanced or metastatic urothelial carcinoma (UC). However, their corresponding target expression characteristics in UC and its histologic variants were unknown.

Methods

We detected the expression of NECTIN-4, TROP-2, and HER2, which are the corresponding targets of ADCs EV, SG, and RC-48 in muscle-invasive UC through immunohistochemistry.

Results

161 consecutive samples from 2017 to 2021 of muscle-invasive UC and its histologic variants were obtained in Peking University First Hospital. Variant histology types included 72UC, 10 squamous carcinomas, 23 glandular carcinomas, 19 small cell carcinomas, 19 micropapillary variants, and 18 nested variants. NECTIN-4 expression was found to be 57/72 (79.2%), 10/10 (100%), 15/23 (65.2%), 4/19 (21.1%), 15/19 (78.9%), and 16/18 (88.9%) in conventional UC, squamous carcinoma, glandular carcinoma, small cell carcinoma, micropapillary, and nested variant, respectively, compared with 65/72 (90.3%), 8/10 (80.0%), 13/23 (56.5%), 3/19 (15.8%), 16/19 (84.2%), and 15/18 (83.3%) of TROP-2, and 26/72 (36.1%), 0, 5/23 (21.7%), 6/19 (31.6%), 5/19 (26.3%), and 7/18 (38.9%) of HER2.

Disitamab vedotin: a novel antibody-drug conjugates for cancer therapy

Human epidermal growth factor receptor 2 (HER2) regulates cell mitosis, proliferation, and apoptosis. Trastuzumab is a HER2-targeted monoclonal antibody (mAB), which can prolong the overall survival rate of patients with HER2 overexpression in later periods of gastric cancer and breast cancer. Although anti-HER2 monoclonal antibody has a curative effect, adjuvant chemotherapy is still necessary to upgrade the curative effect maximumly. Antibody-drug conjugate (ADC) is a kind of therapeutic drug that contains antigen-specific antibody and cytotoxic payload, which can improve the survival time of tumor patients. To date, there are several HER2-ADC products on the market, for which two anti-HER2 ADC (trastuzumab emtansine and trastuzumab deruxtecan) have been authorized by the FDA for distinct types of HER2-positive carcinoma in the breast. Disitamab vedotin (RC48) is a newly developed ADC drug targeting HER2 that is comprised of hertuzumab coupling monomethyl auristatin E (MMAE) via a cleavable linker. This paper aims to offer a general insight and summary of the mechanism of action and the currently completed and ongoing clinical studies of RC-48 in HER-2 positive solid tumors.

Antibody-drug conjugates: beyond current approvals and potential future strategies

The recent approvals for antibody-drug conjugates (ADCs) in multiple malignancies in recent years have fuelled the ongoing development of this class of drugs. These novel agents combine the benefits of high specific targeting of oncogenic cell surface antigens with the additional cell kill from high potency cytotoxic payloads, thus achieving wider therapeutic windows. This review will summarise the clinical activity of ADCs in tumour types not covered elsewhere in this issue, such as gastrointestinal (GI) and genitourinary (GU) cancers and glioblastoma (GBM). In addition to the ongoing clinical testing of existing ADCs, there is substantial preclinical and early phase testing of newer ADCs or ADC incorporating strategies. This review will provide selected insights into such future development, focusing on the development of novel ADCs against new antigen targets in the tumour microenvironment (TME) and combination of ADCs with immuno-oncology (IO) agents.

Constructing an immune- and ferroptosis-related lncRNA signature to predict the immune landscape of human bladder cancer

Background

LncRNAs play a variety of roles in the tumor microenvironment and cancer immune responses. Determining the significance of bladder cancer (BLCA)‐related genes to predict the prognostic and therapeutic response of BLCA is important.

Methods

IrlncRNA/ frlncRNA pairs were determined using univariate analysis. The signature was constructed based on this pairs. Finally, analysis and internal validation were performed from several aspects.

Results

We identified 60 immune‐ and ferroptosis‐related lncRNA pairs, among which 12 were included in the Cox proportional hazards model. Patients in low‐risk group survived for significantly longer. Survival and riskScore analyses showed that the low‐risk group had a significantly better clinical outcome. ROC curve analysis showed that AUC of OS values were more than 0.75 in the training set and the whole cohort. As assessed using Cox analysis, the riskScore was an independent prognostic predictor in the training, testing set and the whole cohort. The areas under the multi‐index ROC in the training set, the testing set, and the whole cohort were 0.777, 0.692, and 0.748, respectively. High‐risk group was positively associated with most of tumor‐infiltrating immune cells. High‐risk Scores correlated positively with high expression of CD274, but not with PD‐1. Low riskScores correlated positively with high expression levels of the genes ERBB2 and nectin‐4. High‐risk Score was associated with a lower IC50 value for Docetaxel, cisplatin, and Pazopanib, while there was an opposite result for metformin.

Conclusions

The signature constructed by pairing irlncRNAs and frlncRNAs showed a notable clinical predictive value.

Targeted Chemoradiotherapy of Prostate Cancer Using Gold Nanoclusters with Protease Activatable Monomethyl Auristatin E

Combined radiotherapy (RT) and chemotherapy are prescribed to patients with advanced prostate cancer (PCa) to increase their survival; however, radiation-related side effects and systematic toxicity caused by chemotherapeutic drugs are unavoidable. To improve the precision and efficacy of concurrent RT and chemotherapy, we have developed a PCa-targeted gold nanocluster radiosensitizer conjugated with a highly potent cytotoxin, monomethyl auristatin E, PSMA-AuNC-MMAE, for RT and chemotherapy of PCa. This approach resulted in enhanced uptake of NCs by PSMA-positive cancer cells, targeted chemotherapy, and increased efficacy of RT both in vitro and in vivo. In addition, the combination of gold and MMAE further increased the efficacy of either of the agents delivered alone or simultaneously but not covalently linked. The PSMA-AuNC-MMAE conjugates improve the specificity and efficacy of radiation and chemotherapy, potentially reducing the toxicity of each therapy and making this an attractive avenue for clinical treatment of advanced PCa.

The Prognostic Role and Significance of Dll4 and Toll-like Receptors in Cancer Development

Simple Summary

The aim of this review is to summarize the latest details considering the role of Dll4 in cancer, since recent data report that Dll4 has a major key role in tumor angiogenesis. Moreover, the authors try to seek any correlation between Dll4 and cancer stem cells in tumor development. Considering that cancer stem cells have proven to be implicated in the progression of many cancer types, any impact from Dll4 could lead to the alteration of cancer development. Additionally, the authors make a report on current advantages on immunotherapy and tumor-draining lymph nodes in cancer. Finally, this study analyzes toll like receptors, pattern recognition receptors that are capable of recognizing different molecules and activating different genes. These immunogenetic molecules have remarkable roles including angiogenesis promotion, while their activation can lead to either cancer progression or inhibition, representing a very promising therapeutic alliance for cancer treatment.

Abstract

The Notch signaling pathway regulates the development of embryonic and tissue homeostasis of various types of cells. It also controls cell proliferation, variation, fate and cell death because it emits short-range messages to nearby cells. The pathway plays an important role in the pathophysiology of various malignancies, controlling cancer creation. It also limits cancer development by adjusting preserved angiogenesis and cellular programs. One of the Notch signaling ligands (in mammals) is Delta-like ligand 4 (Dll4), which plays a significant role in the overall malignancies’ advancement. Particularly, sequencing Notch gene mutations, including those of Dll4, have been detected in many types of cancers portraying information on the growth of particular gynecological types of tumors. The current research article examines the background theory that implies the ability of Dll4 in the development of endometrial and other cancer types, and the probable therapeutic results of Dll4 inhibition.

Antibody-drug conjugates: Smart chemotherapy delivery across tumor histologies

As distinct cancer biomarkers have been discovered in recent years, a need to reclassify tumors by more than their histology has been proposed, and therapies are now tailored to treat cancers based on specific molecular aberrations and immunologic markers. In fact, multiple histology-agnostic therapies are currently adopted in clinical practice for treating patients regardless of their tumor site of origin. In parallel with this new model for drug development, in the past few years, several novel antibody-drug conjugates (ADCs) have been approved to treat solid tumors, benefiting from engineering improvements in the conjugation process and the introduction of novel linkers and payloads. With the recognition that numerous surface targets are expressed across various cancer histologies, alongside the remarkable activity of modern ADCs, this drug class has been increasingly evaluated as suitable for a histology-agnostic expansion of indication. For illustration, the anti-HER2 ADC trastuzumab deruxtecan has demonstrated compelling activity in HER2-overexpressing breast, gastric, colorectal, and lung cancer. Examples of additional novel and potentially histology-agnostic ADC targets include trophoblast cell-surface antigen 2 (Trop-2) and nectin-4, among others. In the current review article, the authors summarize the current approvals of ADCs by the US Food and Drug Administration focusing on solid tumors and discuss the challenges and opportunities posed by the multihistological expansion of ADCs.

Efficacy of Disitamab Vedotin in Treating HER2 2+/FISH- Gastric Cancer

Currently, effective therapies for advanced gastric cancer with systemic metastasis are lacking. Pharmacological research has been slowly progressing over the past decades. Here, we report the case of a 56-year-old female with human epidermal growth factor receptor 2 (HER2) expression (IHC 2+/FISH-) in gastric cancer with systemic metastasis. The first-line therapeutic regime consisted of systemic administration of camrelizumab, local arterial infusion of oxaliplatin and arterial embolization, oral apatinib, and PS scheme (oral tegafur-gimeracil-oteracil (S-1) and paclitaxel (PTX), which was administered both intraperitoneally and systemically). After the treatment, a 3-month progression-free survival (PFS) was observed. Due to the occurrence of CTCAE grade 4 adverse reactions, the patient could not tolerate chemotherapy. In the second line of treatment, we replaced the PS scheme with disitamab vedotin and continued the use of carrilizumab and apatinib. After four cycles, efficacy evaluation showed that it was stable disease (SD), only CTCAE 1/2 grade adverse reactions occurred, and endoscopy examination showed local tumor control with a reduction in the ulcer lesion. At the time of submission of the current manuscript, a 6-month PFS was achieved and the treatment was continued. Due to the safety and efficacy of disitamab vedotin observed in our case, we propose that disitamab vedotin could be a promising drug for the treatment of advanced gastric cancer patients with HER2 expression.

Antibody-Drug Conjugates in Urothelial Carcinoma: A New Therapeutic Opportunity Moves from Bench to Bedside

Significant progress has been achieved over the last decades in understanding the biology and mechanisms of tumor progression in urothelial carcinoma (UC). Although the therapeutic landscape has dramatically changed in recent years with the introduction of immune checkpoint inhibitors, advanced UC is still associated with rapidly progressing disease and poor survival. The increasing knowledge of the pathogenesis and molecular pathways underlying cancer development and progression is leading the introduction of target therapies, such as the recently approved FGFR inhibitor Erdafitinib, or the anti-nectin 4 antibody drug-conjugate Enfortumab vedotin. Antibody drug conjugates represent an innovative therapeutic approach that allows the combination of a tar get-specific monoclonal antibody covalently conjugated via a linker to a cytotoxic agent (payload). UC is a perfect candidate for this therapeutic approach since it is particularly enriched in antigen expression on its surface and each specific antigen can represent a potential therapeutic target. In this review we summarize the mechanism of action of ADCs, their applications in localized and metastatic UC, the main mechanisms of resistance, and future perspectives for their use in clinical practice.

Antibody-Drug Conjugate Targets, Drugs and Linkers

Antibody-drug conjugates offer the possibility of directing powerful cytotoxic agents to a malignant tumor while sparing normal tissue. The challenge is to select an antibody target expressed exclusively or at highly elevated levels on the surface of tumor cells and either not all or at low levels on normal cells. The current review explores 78 targets that have been explored as antibody-drug conjugate targets. Some of these targets have been abandoned, 9 or more are the targets of FDA-approved drugs, and most remain active clinical interest. Antibody-drug conjugates require potent cytotoxic drug payloads, several of these small molecules are discussed, as are the linkers between the protein component and small molecule components of the conjugates. Finally, conclusions regarding the elements for the successful antibody-drug conjugate are discussed.

Novel development strategies and challenges for anti-Her2 antibody-drug conjugates

Antibody-drug conjugates (ADCs) combining potent cytotoxicity of small-molecule drugs with the selectivity and excellent pharmacokinetic profile of monoclonal antibody (mAb) are promising therapeutic modalities for a diverse range of cancers. Owing to overexpression in a wide range of tumors, human epidermal growth factor receptor 2 (Her2) is one of the most utilized targeting antigens for ADCs to treat Her2-positive cancers. Owing to the high density of Her2 antigens on the tumor cells and high affinity and high internalization capacity of corresponding antibodies, 56 anti-Her2 ADCs which applied >10 different types of novel payloads had entered preclinical or clinical trials. Seven of 12 Food and Drug Administration (FDA)-approved ADCs including Polivy (2019), Padcev (2019), EnHertu (2019), Trodelvy (2020), Blenrep (2020), Zynlonta (2021), and Tivdak) (2021) have been approved by FDA in the past three years alone, indicating that the maturing of ADC technology brings more productive clinical outcomes. This review, focusing on the anti-Her2 ADCs in clinical trials or on the market, discusses the strategies to select antibody formats, the linkages between linker and mAb, and effective payloads with particular release and action mechanisms for a good clinical outcome.

From AVATAR Mice to Patients: RC48-ADC Exerted Promising Efficacy in Advanced Gastric Cancer With HER2 Expression

RC48-ADC is a novel humanized antibody specific for human epidermal growth factor receptor 2 (HER2)in conjugation with a microtubule inhibitor via a cleavable linker. This study was to evaluate the antitumor activity and mechanism of RC48-ADC in gastric cancer (GC) and explore the population that may benefit from RC48-ADC treatment. Four human GC cell lines and nine patient-derived xenograft (PDX) models were exploited to evaluate the antitumor effect of RC48-ADC or trastuzumab treatment in vitro and in vivo. The expression and phosphorylation of HER2 were assessed by immunohistochemistry (IHC) staining. Critical molecules of downstream PI3K/AKT and cell cycle and apoptosis signaling pathways were detected and quantified by immunoblotting. Combined with preliminary results of preclinical research, three patients with IHC3+, IHC2+/FISH+, and IHC2+/FISH- of HER2 were enrolled to verify the efficacy of RC48-ADC treatment in advanced GC. In vitro, RC48-ADC had superior antiproliferative effects in a dose-dependent manner on GC cells, especially on HER2-positive cells. In vivo, RC48-ADC exceeded trastuzumab in GC PDX models with HER2 expression, even in models with moderate to low expression of HER2. Further exploration of mechanism showed that RC48-ADC exerted the antitumor effect by inhibiting phosphorylation of HER2, inducing G2/M phase arrest and cell apoptosis in HER2-expressed PDX models. In clinical practice, RC48-ADC had satisfactory efficacy in HER2-positive and HER2 moderately expressed GC patients and demonstrated promising efficacy in HER2-positive patients who have progressed after anti-HER2 therapy. In conclusion, RC48-ADC exerted promising antitumor activity in HER2-positive as well as score of 2+ in IHC and ISH-negative AGC patients after progression of systematic treatment.

Progress in the Research and Targeted Therapy of ErbB/HER Receptors in Urothelial Bladder Cancer

Bladder cancer is a lethal malignancy and a majority of bladder cancer arise from urothelial cells. Infiltration and metastasis are barriers for the radical cystectomy to achieve favored outcome and are the main cause of death. Systemic therapy, including chemotherapy, targeted therapy, and immunotherapy, is fundamental for these patients. erbB/HER receptors are found to be overexpressed in a subgroup of urothelial carcinoma, targeting erbB/HER receptors in these patients was found to be an efficient way in the era of genetic testing. To evaluate the role of erbB/HER receptors in bladder cancer, we reviewed the literature and ongoing clinical trials as regards to this topic to unveil the context of erbB/HER receptors in bladder cancer, which probably help to solidate the theoretical basis and might instruct further research.

Antibody-drug conjugates: Resurgent anticancer agents with multi-targeted therapeutic potential

Antibody-drug conjugates (ADCs) constitute a relatively new group of anticancer agents, whose first appearance took place about two decades ago, but a renewed interest occurred in recent years, following the success of anti-cancer immunotherapy with monoclonal antibodies. Indeed, an ADC combines the selectivity of a monoclonal antibody with the cell killing properties of a chemotherapeutic agent (payload), joined together through an appropriate linker. The antibody moiety targets a specific cell surface antigen expressed by tumor cells and/or cells of the tumor microenvironment and acts as a carrier that delivers the cytotoxic payload within the tumor mass. Despite advantages in terms of selectivity and potency, the development of ADCs is not devoid of challenges, due to: i) low tumor selectivity when the target antigens are not exclusively expressed by cancer cells; ii) premature release of the cytotoxic drug into the bloodstream as a consequence of linker instability; iii) development of tumor resistance mechanisms to the payload. All these factors may result in lack of efficacy and/or in no safety improvement compared to unconjugated cytotoxic agents. Nevertheless, the development of antibodies engineered to remain inert until activated in the tumor (e.g., antibodies activated proteolytically after internalization or by the acidic conditions of the tumor microenvironment) together with the discovery of innovative targets and cytotoxic or immunomodulatory payloads, have allowed the design of next-generation ADCs that are expected to possess improved therapeutic properties. This review provides an overview of approved ADCs, with related advantages and limitations, and of novel targets exploited by ADCs that are presently under clinical investigation.

Novel ADCs and Strategies to Overcome Resistance to Anti-HER2 ADCs

During recent years, a number of new compounds against HER2 have reached clinics, improving the prognosis and quality of life of HER2-positive breast cancer patients. Nonetheless, resistance to standard-of-care drugs has motivated the development of novel agents, such as new antibody-drug conjugates (ADCs). The latter are a group of drugs that benefit from the potency of cytotoxic agents whose action is specifically guided to the tumor by the target-specific antibody. Two anti-HER2 ADCs have reached the clinic: trastuzumab-emtansine and, more recently, trastuzumab-deruxtecan. In addition, several other HER2-targeted ADCs are in preclinical or clinical development, some of them with promising signs of activity. In the present review, the structure, mechanism of action, and potential resistance to all these ADCs will be described. Specific attention will be given to discussing novel strategies to circumvent resistance to ADCs.

Treatment options for advanced urothelial cancer after progression on chemotherapy and immune checkpoint inhibitors: a literature review

Objective

To describe the current treatment landscape in advanced urothelial cancer (aUC)/metastatic urothelial cancer and in particular to review the relevant literature highlighting recent advances in the treatment of patients with aUC after progression on chemotherapy and immune checkpoint inhibitor (ICI).

Background

aUC is a very aggressive disease with poor outcomes. Over the past several years, its treatment landscape has seen significant advances with the approval of ICI and targeted agents, which have led to improved outcomes. The current standard of care for most patients with aUC involves platinum-based chemotherapy followed by ICI after progression or as switch maintenance therapy (if no progression after chemotherapy). Treatment of patients following progression on ICI is more challenging, but novel therapies have been approved, such as erdafitinib for tumors with fibroblast growth factor receptor 2 (FGFR2) or FGFR3 activating mutation or fusion (can also be used following progression on platinum-based chemotherapy), enfortumab vedotin (EV) and sacituzumab govitecan (SG) in an unselected patient population. Many other trials in this space are currently ongoing and other promising agents may also potentially become available in the future.

Methods

Narrative overview of the recent literature relevant to the treatment of advanced/metastatic urothelial cancer following progression on chemotherapy and ICI was undertaken. Relevant literature was obtained from review of computerized databases including pubmed.gov and proceedings of major conferences including American Society of clinical Oncology (ASCO) Meetings, GU ASCO Symposia and European Society of Medical Oncology (ESMO) Meetings.

Conclusions

In this narrative review, we highlight the current dynamic treatment landscape in aUC, emphasizing the recent important developments and a few examples of ongoing clinical trials. In particular, we focus on therapy options available following progression on platinum-based chemotherapy and ICI, a treatment space where until recently there had been no FDA-approved treatment options. The recent pivotal trials of antibody drug conjugates (ADCs) that led to FDA approvals in this space are highlighted, as are other agents currently in development. We conclude by discussing future directions and ongoing challenges in this evolving disease space.

Safety, Efficacy and Biomarker Analysis of Toripalimab in Patients with Previously Treated Advanced Urothelial Carcinoma: Results from a Multicenter Phase II Trial POLARIS-03

PURPOSE

Immunotherapy offers a second-line option for patients with metastatic urothelial carcinoma (mUC) who failed standard therapy, but the biomarkers for predicting response remain to be explored. This study aims to evaluate the safety, efficacy, and correlative biomarker of toripalimab in patients with previously treated mUC.

EXPERIMENTAL DESIGN

Patients with mUC received toripalimab 3 mg/kg Q2W. Clinical response was assessed every 8 weeks by an independent review committee per RECIST v1.1. Tumor PD-L1 expression, tumor mutational burden (TMB), and other biomarkers were evaluated.

RESULTS

Among the intention-to-treat population (n = 151), 85% of the patients experienced treatment-related adverse event (TRAE) and 20% experienced grade 3 and above TRAE. The objective response rate (ORR) was 26% with a disease control rate (DCR) of 45%. The median duration of response, progression-free survival (PFS) and overall survival (OS) were 19.7 months (95% CI: 13.9 to NE), 2.3 months (95% CI: 1.8 to 3.6) and 14.4 months (95% CI: 9.3 to 23.1), respectively. Both PD-L1+ and TMB-high (10 mutations/Mb as the cut off) patients had better ORR than PD-L1- patients (42% versus 17%, p = 0.002) and TMB low patients (48% versus 22%, p = 0.014), respectively. The TMB-high group also showed better PFS (12.9 versus 1.8 months, p < 0.001) and OS (not reached versus 10.0 months, p = 0.018) than the TMB-low group.

CONCLUSIONS

Toripalimab has demonstrated encouraging clinical activity in the second-line treatment of mUC with a manageable safety profile. PD-L1 expression and TMB were two independent biomarkers in the study.

Disitamab Vedotin: First Approval

Disitamab vedotin (Aidixi®) is an antibody-drug conjugate comprising a monoclonal antibody against human epidermal growth factor receptor 2 (HER2) conjugated via a cleavable linker to the cytotoxic agent monomethyl auristatin E. Disitamab vedotin is being developed by RemeGen for the treatment of solid tumours, including gastric cancer; Seagen has the right to develop disitamab vedotin globally outside of RemeGen's territory. In June 2021, disitamab vedotin received its first Biologics License Application (BLA) approval in China for the treatment of patients with HER2-overexpressing (defined as IHC2+ or 3+) locally advanced or metastatic gastric cancer (including gastroesophageal junction adenocarcinoma) who have received at least two systemic chemotherapy regimens. Disitamab vedotin as monotherapy or combination therapy is also in clinical development for the treatment of other solid tumours globally, including urothelial cancer in China and the USA, and biliary tract cancer, non-small cell lung cancer and HER2-positive and HER2-low expressing breast cancer in China. This article summarizes the milestones in the development of disitamab vedotin leading to this first approval for locally advanced or metastatic gastric cancer.

Efficacy and safety of a novel anti-HER2 therapeutic antibody RC48 in patients with HER2-overexpressing, locally advanced or metastatic gastric or gastroesophageal junction cancer: a single-arm phase II study

Background

Current treatment options for human epidermal growth factor receptor 2 (HER2)‐overexpressing gastric cancer at third‐line have shown limited clinical benefit. Further, there is no specific treatment for HER2 immunohistochemistry (IHC) 2+ and fluorescence in‐situ hybridization‐negative patients. Here, we report the efficacy and safety of a novel anti‐HER2 antibody RC48 for patients with HER2‐overexpressing, advanced gastric or gastroesophageal junction cancer.

Methods

Patients with HER2‐overexpressing (IHC 2+ or 3+), locally advanced or metastatic gastric or gastroesophageal junction cancer who were under at least second‐line therapy were eligible and received RC48 2.5 mg/kg alone every 2 weeks. The primary endpoint was the objective response rate (ORR) assessed by an independent review committee. Secondary endpoints included progression‐free survival (PFS), overall survival (OS), duration of response, time to progression, disease control rate, and safety.

Results

Of 179 patients screened, 125 were eligible and received RC48 treatment. The ORR was 24.8% (95% confidence interval [CI]: 17.5%‐33.3%). The median PFS and OS were 4.1 months (95% CI: 3.7‐4.9 months) and 7.9 months (95% CI: 6.7‐9.9 months), respectively. The most frequently reported adverse events were decreased white blood cell count (53.6%), asthenia (53.6%), hair loss (53.6%), decreased neutrophil count (52.0%), anemia (49.6%), and increased aspartate aminotransferase level (43.2%). Serious adverse events (SAEs) occurred in 45 (36.0%) patients, and RC48‐related SAEs were mainly decreased neutrophil count (3.2%). Seven patients had adverse events that led to death were not RC48‐related.

Conclusions

RC48 showed promising activity with manageable safety, suggesting potential application in patients with HER2‐overexpressing, advanced gastric or gastroesophageal junction cancer who have previously received at least two lines of chemotherapy.

Interstitial Lung Disease Induced by Anti-ERBB2 Antibody-Drug Conjugates: A Review

Importance

In the past decade, ERBB2 (formerly HER2)-directed antibody-drug conjugates (ADCs) have substantially changed treatment of both advanced and early-stage ERBB2-positive breast cancer. Novel conjugates are now showing activity in trials of other ERBB2-associated tumors, leading to the recent US Food and Drug Administration approval of trastuzumab deruxtecan for ERBB2-positive gastric cancer, as well as beneficial results in colorectal, lung, and bladder cancer. It is thus possible that anti-ERBB2 ADCs may become a treatment option for multiple types of tumors because many have at least some expression of ERBB2. Despite an improved overall therapeutic index, clinical observations have recently raised a concern regarding potential lung toxicity of anti-ERBB2 ADCs. Deaths related to interstitial lung disease (ILD) have been reported with variable incidence in trials testing anti-ERBB2 conjugates, warranting appropriate training of clinicians for the identification and management of this toxic effect.

Observations

Although no specific guidelines are available for the diagnosis and management of ADC-related ILD, some recommendations can be derived based on general principles adopted for drug-induced and immunotherapy-related ILD. Overall, in symptomatic ILD, the ADC should be discontinued. Reintroduction of the conjugate can be considered only in asymptomatic cases after complete resolution. Corticosteroids represent the cornerstone of ILD treatment, and dosing should be adapted according to the severity of the event. Additional treatments can be considered based on the clinical scenario.

Conclusions and Relevance

This review summarizes the current knowledge on the pathogenesis and epidemiologic characteristics of anti-ERBB2 ADC-related lung toxicity, proposing strategies for its diagnosis and treatment. Earlier diagnosis and more adequate treatment of ADC-induced ILD may improve the therapeutic index of this important class of anticancer agents, allowing for a safe expansion of anti-ERBB2 ADCs across tumor types.

Clinicopathologic features and treatment advances in cancers with HER2 alterations

HER2 is one of the most important proteins of the epidermal growth factor receptor (EGFR) family, whose alterations include amplification, overexpression and gene mutation. Growing attention has been given to HER2 as a biomarker for prognosis, an indicator for treatment response and a target for new drugs. Tumors with HER2 alterations have been well studied in multiple locations as distinct entities for treatment, especially breast cancer, gastric cancer, lung cancer and colorectal cancer. These four cancers are the leading causes of cancer incidence and cancer-related death worldwide. The present study details the landscape of HER2 amplification/overexpression and mutations and gives an up-to-date analysis of current clinical trials in the four cancers mentioned above. Different HER2-altered cancers not only respond differently to HER2-targeting therapies but also display diverse survival outcomes. Even in the same type of cancer, HER2 amplification/overexpression differs from HER2 mutation in terms of clinicopathologic features and treatment strategies. As an emerging strategy in cancer treatment, immune checkpoint inhibitors demonstrate distinct outcomes in HER2-altered breast cancer, gastric cancer and lung cancer.

Development of Marine-Derived Compounds for Cancer Therapy

Cancer has always been a threat to human health with its high morbidity and mortality rates. Traditional therapy, including surgery, chemotherapy and radiotherapy, plays a key role in cancer treatment. However, it is not able to prevent tumor recurrence, drug resistance and treatment side effects, which makes it a very attractive challenge to search for new effective and specific anticancer drugs. Nature is a valuable source of multiple pharmaceuticals, and most of the anticancer drugs are natural products or derived from them. Marine-derived compounds, such as nucleotides, proteins, peptides and amides, have also shed light on cancer therapy, and they are receiving a fast-growing interest due to their bioactive properties. Their mechanisms contain anti-angiogenic, anti-proliferative and anti-metastasis activities; cell cycle arrest; and induction of apoptosis. This review provides an overview on the development of marine-derived compounds with anticancer properties, both their applications and mechanisms, and discovered technologies.

Anti-tumour drugs of marine origin currently at various stages of clinical trials (review)

Oncological diseases for a long time have remained one of the most significant health problems of modern society, which causes great losses in its labour and vital potential. Contemporary oncology still faces unsolved issues as insufficient efficacy of treatment of progressing and metastatic cancer, chemoresistance, and side-effects of the traditional therapy which lead to disabilities among or death of a high number of patients. Development of new anti-tumour preparations with a broad range of pharmaceutical properties and low toxicity is becoming increasingly relevant every year. The objective of the study was to provide a review of the recent data about anti-tumour preparations of marine origin currently being at various phases of clinical trials in order to present the biological value of marine organisms – producers of cytotoxic compounds, and the perspectives of their use in modern biomedical technologies. Unlike the synthetic oncological preparations, natural compounds are safer, have broader range of cytotoxic activity, can inhibit the processes of tumour development and metastasis, and at the same time have effects on several etiopathogenic links of carcinogenesis. Currently, practical oncology uses 12 anti-tumour preparations of marine origin (Fludarabine, Cytarabine, Midostaurin, Nelarabine, Eribulin mesylate, Brentuximab vedotin, Trabectedin, Plitidepsin, Enfortumab vedotin, Polatuzumab vedotin, Belantamab mafodotin, Lurbinectedin), 27 substances are at different stages of clinical trials. Contemporary approaches to the treatment of oncological diseases are based on targeted methods such as immune and genetic therapies, antibody-drug conjugates, nanoparticles of biopolymers, and metals. All those methods employ bioactive compounds of marine origin. Numerous literature data from recent years indicate heightened attention to the marine pharmacology and the high potential of marine organisms for the biomedicinal and pharmaceutic industries.

HER2-targeted therapies in gastric cancer

Molecular targeted therapy of cancer has always been the focus of clinicians. Among those therapeutic targets, the human epidermal growth factor receptor-2 (HER-2) signaling pathway is one of the most popular targets for translational research in cancer. However, unlike prospect in breast cancer, HER-2 inhibitor trastuzumab is the only molecular targeted drug approved by US Food and Drug Administration (FDA) for the first-line treatment of HER-2 positive advanced gastric cancer. On this basis, a variety of novel HER2- targeted drugs for gastric cancer are under development, and related clinical researches are in full swing, including small molecular kinase inhibitors (e.g., afatinib, neratinib, pyrotinib), antibody-drug conjugates (e.g., DS-8201a, RC48-ADC) and other novel therapies (e.g., ZW25, CAR-T, BVAC-B). In this study, we will summarize the recent advances in anti-HER-2 agents, potential mechanisms of resistance to HER2-targeted therapy in HER2-positive gastric cancer. We will also discuss the future prospects of potential strategies to overcome anti-HER-2 resistance and development of novel anti-HER-2 approaches for the treatment of HER2-positive gastric cancer patients.

Small Molecule-Based Prodrug Targeting Prostate Specific Membrane Antigen for the Treatment of Prostate Cancer

Metastatic castration-resistant prostate cancer poses a serious clinical problem with poor outcomes and remains a deadly disease. New targeted treatment options are urgently needed. PSMA is highly expressed in prostate cancer and has been an attractive biomarker for the treatment of prostate cancer. In this study, we explored the feasibility of targeted delivery of an antimitotic drug, monomethyl auristatin E (MMAE), to tumor tissue using a small-molecule based PSMA lig-and. With the aid of Cy5.5, we found that a cleavable linker is vital for the antitumor activity of the ligand-drug conjugate and have developed a new PSMA-targeting prodrug, PSMA-1-VcMMAE. In in vitro studies, PSMA-1-VcMMAE was 48-fold more potent in killing PSMA-positive PC3pip cells than killing PSMA-negative PC3flu cells. In in vivo studies, PSMA-1-VcMMAE significantly inhibited tumor growth leading to prolonged animal survival in different animal models, including metastatic prostate cancer models. Compared to anti-PSMA antibody-MMAE conjugate (PSMA-ADC) and MMAE, PSMA-1-VcMMAE had over a 10-fold improved maximum tolerated dose, resulting in improved therapeutic index. The small molecule-drug conjugates reported here can be easily synthesized and are more cost efficient than anti-body-drug conjugates. The therapeutic profile of the PSMA-1-VcMMAE encourages further clin-ical development for the treatment of advanced prostate cancer.

Targeting cancer with antibody-drug conjugates: Promises and challenges

Antibody-drug conjugates (ADCs) are a rapidly expanding class of biotherapeutics that utilize antibodies to selectively deliver cytotoxic drugs to the tumor site. As of May 2021, the U.S. Food and Drug Administration (FDA) has approved ten ADCs, namely Adcetris®, Kadcyla®, Besponsa®, Mylotarg®, Polivy®, Padcev®, Enhertu®, Trodelvy®, Blenrep®, and Zynlonta™ as monotherapy or combinational therapy for breast cancer, urothelial cancer, myeloma, acute leukemia, and lymphoma. In addition, over 80 investigational ADCs are currently being evaluated in approximately 150 active clinical trials. Despite the growing interest in ADCs, challenges remain to expand their therapeutic index (with greater efficacy and less toxicity). Recent advances in the manufacturing technology for the antibody, payload, and linker combined with new bioconjugation platforms and state-of-the-art analytical techniques are helping to shape the future development of ADCs. This review highlights the current status of marketed ADCs and those under clinical investigation with a focus on translational strategies to improve product quality, safety, and efficacy.