HER2-targeting antibody-drug conjugate RC48 alone or in combination with immunotherapy for locally advanced or metastatic urothelial carcinoma: a multicenter, real-world study

Progress of antibody-drug conjugates in the treatment of locally advanced or metastatic urothelial carcinoma: opportunities and challenges

PURPOSE OF REVIEW

The objective of this review is to provide an overview of the clinical progress, administration methods, efficacy, safety, and treatment-related adverse events associated with antibody-drug conjugates.

RECENT FINDINGS

Locally advanced or metastatic urothelial carcinoma is an aggressive and lethal malignancy. Cisplatin-based chemotherapy has been the first-line therapy for most patients over the past two decades. However, approximately 50% of patients with locally advanced or metastatic urothelial carcinoma are ineligible for cisplatin-based chemotherapy due to inadequate renal function, poor performance status, or complications. Furthermore, patients who exhibit suboptimal responses or disease progression following platinum-based chemotherapy face therapeutic uncertainty regarding the selection of alternative agents. The emergence of antibody-drug conjugates has provided new options for patients afflicted with this disease, particularly enfortumab vedotin combined with pembrolizumab as a new first-line therapy for advanced urothelial carcinoma or for patients ineligible for platinum-based therapy. Additionally, in the TROPICS-04 trial, sacituzumab govitecan failed to demonstrate significant improvement in overall survival or progression-free survival compared with the physician's choice of treatment for patients with advanced urothelial carcinoma progressing after platinum-based chemotherapy and PD-(L)1 inhibitor therapy; the FDA withdrew its approval for this indication. ADCs are also being considered for the treatment of muscle-invasive bladder cancer, with ongoing clinical trials.

RC48-ADC monotherapy or in combination with immunotherapy for locally advanced or metastatic urothelial carcinoma with HER2 low and null expression: a multicenter, real-world, retrospective study

BACKGROUND

Approximately half of urothelial carcinoma (UC) patients exhibit low or null HER2 expression. Limited data are available on the efficacy of anti-HER2 RC48-ADC (Disitamab Vedotin) in HER2 low and null advanced UC.

METHODS

Patients with locally advanced or metastatic UC (la/mUC) with HER2 low (IHC 1+) and null (IHC 0) expression who received RC48-ADC monotherapy or in combination with programmed cell death protein 1 (PD-1) inhibitors were enrolled in this multi-center, retrospective study. The primary endpoint was objective response rate (ORR). Secondary endpoints included disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and adverse events (AEs).

RESULTS

A total of 27 patients were included, with a median age of 64 years, and 17 (63%) were male. Seven (26.0%) patients received RC48-ADC alone, and 20 (74.1%) received RC48-ADC combined with a PD-1 inhibitor. Eight (30.8%) patients achieved partial response (PR), and twelve (46.2%) exhibited stable disease (SD). The ORR was 30.8%, and DCR was 76.9%. The median PFS and OS were 7.4 months and 13.8 months, one-year PFS and OS rates were 29.1% and 57.2%, respectively. Both RC48 monotherapy and combination were well-tolerated. Grade 3 AEs occurred in 4 (14.8%) patients received combination treatment, including 2 cases of anemia, 1 case of increased serum creatinine, and 1 case of autoimmune encephalitis. No grade 3 or higher AEs were observed in RC48-ADC monotherapy.

CONCLUSION

RC48-ADC demonstrated favorable efficacy and manageable safety in la/mUC patients with HER2 low and null expression in real-world settings. Prospective studies with large sample size are warranted to validate this finding.

Efficacy and safety of RC48 in combination with PD-1 inhibitors for the treatment of locally advanced or metastatic urothelial carcinoma: a single-center, real-world study

OBJECTIVE

This study aims to assess the efficacy and safety of RC48 in combination with PD-1 inhibitors for patients diagnosed with locally advanced or metastatic urothelial carcinoma (mUC).

METHODS

A retrospective analysis was performed on clinical data from 53 patients with locally advanced or metastatic bladder cancer, who were treated at the First Affiliated Hospital of Bengbu Medical College between January 2023 and December 2023. The cohort was stratified into two groups: the RC48 combined immunotherapy group (RC48 + PD-1, n = 27) and the conventional chemotherapy group (gemcitabine and cisplatin regimen, GP, n = 26).

RESULTS

The RC48 + PD-1 group demonstrated significantly higher objective response rates (ORR) and median progression-free survival (PFS) compared to the chemotherapy group (P < 0.05). Notably, the incidence of grade 3 or higher adverse events was elevated in the chemotherapy cohort, predominantly due to hematologic toxicities, with no treatment-related fatalities reported. In contrast, the RC48 combined PD-1 group primarily experienced immune-related adverse events, without any incidents of grade 3 or higher adverse effects or treatment-related deaths.

CONCLUSION

The combination of RC48 and PD-1 inhibitors exhibits promising antitumor activity and a manageable safety profile in patients with locally advanced or metastatic UC.

The effectiveness and safety of RC48 alone or in combination with PD-1 inhibitors for locally advanced or metastatic urothelial carcinoma: a multicenter, real-world study

BACKGROUND

RC48 is an antibody-drug conjugate (ADC) specifically targeting HER2. Phase II and III clinical trials have proven its significant anti-tumor effect against locally advanced or metastatic urothelial carcinoma (la/mUC). This study aims to further assess the effectiveness and safety of RC48 for patients with la/mUC and provide insights for further clinical practice.

METHODS

Retrospective analysis for 42 patients with la/mUC who underwent RC48 alone or in combination with PD-1 inhibitors therapy between 18 October 2022 and 1 May 2024 were conducted to assess effectiveness and safety of RC48. Descriptive statistics were used to summarize baseline characteristics, treatment-related adverse events, etc. Cox proportional risk model and the Kaplan-Meier method were applied to analyze patients' survival.

RESULTS

We observed a median progression-free survival (mPFS) of 6.2 months, although median overall survival (mOS) has not been reached so far. An objective response rate (ORR) of 54.8% and a disease control rate (DCR) of 83.3% was also observed. Patients with first-line therapy, second- or later-line therapy and neoadjuvant therapy were observed disease remission with ORRs of 47.7%, 40.0% and 100.0%, respectively. The most common treatment-related adverse events (TRAEs) include hypoesthesia and elevated transaminases which affect over 90.0% of patients and mostly grade 1-2 in severity, and no treatment-related fatalities were found.

CONCLUSIONS

This multicenter, real-world study confirms that RC48 alone or in combination with PD-1 inhibitors exerted a promising effectiveness and manageable safety for first-line, second- and post-line, and neoadjuvant therapy with la/mUC.

Amide Proton Transfer-Weighted Imaging in Assessing the Aggressive and Proliferative Potential of Bladder Cancer

BACKGROUND

Ki-67 and human epidermal growth factor receptor 2 (HER2) are known oncogenes involved in bladder cancer (BCa) patient risk stratification. Preoperative assessment of their expression level can assist in clinical treatment decision-making. Recently, amide proton transfer-weighted (APTw) MRI has shown promising potential in the diagnosis of several malignancies. However, few studies reported the value of APTw imaging in evaluating Ki-67 and HER2 status of BCa.

PURPOSE

To investigate the feasibility of APTw MRI in assessing the aggressive and proliferative potential regarding the expression levels of Ki-67 and HER2 in BCa.

STUDY TYPE

Retrospective.

SUBJECTS

114 patients (mean age, 64.78 ± 11.93 [SD] years; 97 men) were studied.

FIELD STRENGTH/SEQUENCE

APTw MRI acquired by a three-dimensional fast-spin-echo sequence at 3.0 T MRI system.

ASSESSMENT

Patient pathologic findings, included histologic grade and the expression status of Ki-67 and HER2, were reviewed by one uropathologist. The APTw values of BCa were independently measured by two radiologists and were compared between high-/low-tumor grade group, high-/low-Ki-67 expression group, and high-/low-HER2 expression group.

STATISTICAL TESTS

The interclass correlation coefficient, independent sample t-test, Mann-Whitney U test, Spearman's rank correlation, and receiver operating characteristic curve (ROC) analysis were used. P < 0.05 was considered statistically significant.

RESULTS

Significantly higher APTw values were found in high-grade BCa patients (7.72% vs. 4.29%, P < 0.001), high-Ki-67 expression BCa patients (8.40% vs. 3.25%, P < 0.001) and HER2 positive BCa patients (8.24% vs. 5.40%, P = 0.001). APTw values were positively correlated with Ki-67 (r = 0.769) and HER2 (r = 0. 356) expression status. The area under the ROC curve of the APTw values for detecting Ki-67 and HER2 expression status were 0.883 (95% CI: 0.790-0.945) and 0.713 (95% CI: 0.592-0.816), respectively.

DATA CONCLUSIONS

APTw MRI is a potential method to assess the biological and proliferation potential of BCa.

LEVEL OF EVIDENCE: 4

TECHNICAL EFFICACY

Stage 2.

Impact of HER2 Expression on the Prognosis of Muscle-Invasive Bladder Cancer Patients Treated with Bladder-Preservation Comprehensive Therapy

BACKGROUND

HER2 expression has been confirmed to be associated with bladder cancer aggressiveness. Anti-HER2 RC48-ADC is approved in China for the treatment of patients with advanced urothelial carcinoma with failed chemotherapy who are HER2 positive (IHC 2 + or 3 +). The discovery of HER2 positivity in urothelial carcinoma and the development of anti-HER2 drugs have brought new hope for bladder preservation treatment in MIBC.

OBJECTIVE

To investigate HER2 expression in MIBC patients and its correlations with clinical characteristics, to analyze the impact of HER2 expression on the prognosis of MIBC patients administered bladder-preservation comprehensive therapy, and to explore the efficacy and safety of RC48-ADC in MIBC patients administered bladder-preservation comprehensive therapy.

METHODS

We retrospectively collected information on MIBC patients. All 217 patients underwent cTURBT, of whom 175 received GC chemotherapy, while the remaining 42, due to intolerance to GC chemotherapy and HER2 positivity (IHC 2 + or 3 +), received RC48-ADC treatment. Of the 175 patients administered cTURBT combined with GC chemotherapy, 92 and 83 were HER2-negative and HER2-positive, respectively. Recurrence-free survival (RFS) and overall survival (OS) in HER2-negative and HER2-positive patients were compared to analyze the correlation between HER2 expression and prognosis. RFS and OS in the 83 HER2-positive patients administered cTURBT combined with GC chemotherapy and the 42 HER2-positive patients administered cTURBT combined with RC48-ADC were compared to analyze the differences in prognosis between the two treatment methods. The adverse reactions of GC and RC48-ADC were also compared.

RESULTS

Among the 217 included patients, 125 (57.6%) were HER2 positive (IHC 2 + or 3 +). HER2 positivity was significantly associated with tumor size, multifocality, pathological grade, tumor stage, and pelvic lymph node metastasis (P < 0.05). Totally 175 patients underwent cTURBT combined with GC chemotherapy, including 92 HER2-negative and 83 HER2-positive cases. There were no significant differences in gender, age, smoking status, tumor location, and ECOG score between the two groups (P > 0.05), but the proportions of patients with tumors > 3 cm, multifocal tumors, T3 stage, high-grade tumors, and pelvic lymph node metastasis were higher in the HER2-positive group versus the HER2-negative group (P < 0.05). Tumor recurrence rate in the 83 HER2-positive patients was 67.5%, with a median RFS of 19.0 months (95% CI: 10.3-27.7). Totally 22 deaths occurred during the follow-up period, with a median OS of 56.0 months (95% CI: 45.7-66.3). In the 92 HER2-negative patients, the tumor recurrence rate was 56.5%, with a median RFS of 36.0 months (95% CI: 26.1-45.9); 4 deaths occurred during the follow-up period, with the median OS not reached. After cTURBT, of the 125 HER2-positive patients examined, 83 were included in the GC treatment group versus 42 in the RC48-ADC group. There were no differences in gender, age, smoking status, tumor location, tumor size, multifocality, clinical T stage, pathological grade, pelvic lymph node metastasis, and ECOG score between the two groups (P > 0.05). In the GC group, 56 recurrences (67.5%) were detected during the follow-up period, with a median RFS of 19.0 months (95% CI: 10.3-27.7); meanwhile, 22 deaths (52.4%) occurred, with a median OS of 56.0 months (95% CI: 45.7-66.3). In the RC48-ADC group, 15 recurrences (35.7%) were recorded during the follow-up period, with the median RFS not reached; there were 2 deaths (4.8%), with the median OS not reached. The incidence rates of any-grade and grade ≥ 3 adverse reactions were both lower in the RC48-ADC group than in the GC treatment group.

CONCLUSIONS

This study confirms that cTURBT combined with RC48-ADC treatment for HER2-positive MIBC is superior to combined GC treatment in terms of RFS and OS, representing an effective treatment regimen for bladder preservation in MIBC patients.

Integrating single cell and bulk RNA sequencing data identifies RBM17 as a novel response biomarker for immunotherapy in bladder cancer

Checkpoint inhibitors (CPIs) have been widely applied in the treatment of patients with bladder cancer (BLCA). However, there is still unmet need to dissect response predict biomarkers. To uncover CPI response-related marker genes in cancer cells, we utilized SCISSOR, integrating single-cell RNA and bulk RNA sequencing data. Transcriptomic and clinical data from IMvigor210, UNC-108, and BCAN/HCRN datasets were collected to evaluate and validate the identified biomarkers and signatures. Additionally, we analyzed TCGA-BLCA and local-BLCA RNA-seq data to investigate alternative splicing events (ASEs). Cell viability was assessed in T24 and UMUC3 cells with RBM17 upregulation or downregulation. Through SCISSOR analysis, we discovered that the expression levels of RBM17, TAP1, and PSMB8 were significantly associated with CPI response. Since PSMB8 displayed a highly positive correlation with TAP1, we developed a CPI response score (CRS) signature based on the expression profiles of RBM17 and TAP1. The CRS demonstrated robust predictive capacity in IMvigor210, UNC-108, and BCAN/HCRN datasets and was associated with higher tumor mutational burden (TMB), PD-L1 expression, and unique genomic features. Notably, RBM17 was not linked to the clinical outcomes of BLCA patients but positively correlated with BLCA cell proliferation in vitro. In the meantime, RBM17 was correlated with higher activity in core biological pathways, including antigen processing machinery, CD8 + T effector cells, cell cycle, DNA damage repair, epithelial-mesenchymal transition, histone regulation, and immune checkpoints. Moreover, the high-RBM17 group showed enrichment of LumU/Ba/sq subtypes but fewer FGFR3 alterations. Lastly, RBM17 significantly upregulated ASEs in BLCA samples, leading to higher neoantigen levels, a more inflamed tumor microenvironment, and improved CPI response. RBM17 is associated with higher ASEs and neoantigen levels, thereby potentiating the efficacy of CPI in BLCA. The established predictive signature, utilizing only two genes, has the potential to streamline clinical applications, providing a cost-effective alternative to expensive genomic, transcriptomic, and biological feature tests.

Performance of a HER2 testing algorithm tailored for urothelial bladder cancer: A Bi-centre study

Aims

This study aimed to develop an AI algorithm for automated HER2 scoring in urothelial bladder cancer (UBCa) and assess the interobserver agreement using both manual and AI-assisted methods based on breast cancer criteria.

Methods and Results

We utilized 330 slides from two institutions for initial AI development and selected 200 slides for the ring study, involving six pathologists (3 senior, 3 junior). Our AI algorithm achieved high accuracy in two independent tests, with accuracies of 0.94 and 0.92. In the ring study, the AI-assisted method improved both accuracy (0.66 vs 0.94) and consistency (kappa=0.48; 95 % CI, 0.443-0.526 vs kappa=0.87; 95 % CI, 0.852-0.885) compared to manual scoring, especially in HER2-low cases (F1-scores: 0.63 vs 0.92). Additionally, in 62.3 % of heterogeneous HER2-positive cases, the interpretation accuracy significantly improved (0.49 vs 0.93). Pathologists, particularly junior ones, experienced enhanced accuracy and consistency with AI assistance.

Conclusions

This is the first study to provide a quantification algorithm for HER2 scoring in UBCa to assist pathologists in diagnosis. The ring study demonstrated that HER2 scoring based on breast cancer criteria can be effectively applied to UBCa. Furthermore, AI assistance significantly improves the accuracy and consistency of interpretations among pathologists with varying levels of experience, even in heterogeneous cases.

Efficacy of disitamab vedotin in non-small cell lung cancer with HER2 alterations: a multicenter, retrospective real-world study

Background

Non-small cell lung cancer (NSCLC) with human epidermal growth factor receptor 2 (HER2) alterations poses a substantial treatment challenge. Current HER2-targeted therapies offer limited efficacy. Antibody-drug conjugates (ADCs) targeting HER2 have emerged as a promising therapeutic strategy. This study aimed to evaluate the clinical response to a novel ADC drug Disitamab vedotin (RC48) in advanced NSCLC with HER2 alterations.

Methods

This study conducted a retrospective review of patients harboring HER2 alterations treated with RC48 in the real world. Clinical outcomes were evaluated in terms of objective response rate (ORR), disease control rate (DCR), and progression-free survival (PFS).

Results

Out of 22 patients, 21 (95.5%) received RC48 combination therapy, while one received RC48 monotherapy. The ORR of all patients reached 45.5%, and the DCR stood at 90.9%. The median PFS (mPFS) was 7.5 months. Among patients receiving RC48 combination therapy, the ORR was 47.7%, and the mPFS of 8.1 months. The combination of RC48 with platinum+/- bevacizumab resulted in the highest ORR of 71.4% (5 out of 7 patients), with HER2 TKI following at a 50.0% ORR (4 out of 8 patients). First-line (1L) treatment with RC48 showed an ORR of 62.5% (5 out of 8 patients), second-line (2L) treatments had a 57.1% ORR (4 out of 7 patients), and beyond second-line (>2L) treatments exhibited a 14.3% ORR (1 out of 7 patients). Patients with 1L, 2L, or >2L treatment had a mPFS of 8.1 months, 7.2 months, and 7.4 months, respectively. Patients with HER2 mutations or amplifications, and those with concurrent mutations and amplifications at baseline, showed mPFS of 8.1 months, 9.4 months, and 7.4 months, respectively. The mPFS was significantly longer in patients with HER2 amplification. The most common adverse events included hand-foot syndrome (54.5%), asthenia (50.0%), decreased white blood cell count (45.5%), and liver impairment (45.5%). Grade 3 adverse events occurred in one (4.5%) patient.

Conclusion

RC48, particularly in combination regimens, demonstrates promising efficacy in advanced NSCLC with HER2 alterations. These findings underscore the need for further research to validate RC48's application in clinical practice.

Landscape of clinical drug development of ADCs used for the pharmacotherapy of cancers: an overview of clinical trial registry data from 2002 to 2022

BACKGROUND

To provide reference for clinical development of ADCs in the industry, we analyzed the landscape and characteristics of clinical trials about antibody-drug conjugates (ADCs).

METHOD

Clinical trials to study ADCs used for the pharmacotherapy of cancers initiated by the sponsor were searched in the Cite line Pharma Intelligence (Trialtrove database), and the landscape and characteristics of these clinical trials were analyzed from multiple perspectives, such as the number, phases, status, indications, and targets of the clinical trials.

RESULT

As of December 31, 2022, a total of 431 clinical trials have been initiated to study ADCs used for the pharmacotherapy of cancers, and the number of the last 10 years was 5.5 times as large as the first 11 years. These clinical trials involved 47 indications, including breast cancer, lymphoma (lymphoma, non-Hodgkin's and lymphoma, Hodgkin's), unspecified solid tumor, bladder cancer and lung cancer (lung, non-small cell cancer and lung, small cell cancer). As for each of these five indications, 50 + clinical trials have been carried out, accounting for as high as 48.50% (454/936). ADCs involve 38 targets, which are relatively concentrated. Among them, ERBB2 (HER2) and TNFRSF8 (CD30) involve in 100 + registered clinical trials, and TNFRSF17 (BCMA), NECTIN4 and CD19 in 10 + trials. The clinical trials for these five targets account for 79.02% (354/448) of the total number. Up to 93.97% (405/431) of these clinical trials explored the correlation between biomarkers and efficacy. Up to 45.91% (292/636) of Lots (lines of treatment) applied in the clinical trials were the second line. Until December 31, 2022, 54.52% (235/431) of the clinical trials have been completed or terminated.

CONCLUSION

ADCs are a hotspot of research and development in oncology clinical trials, but the indications, targets, phases, and Lot that have been registered are seemingly relatively concentrated at present. This study provides a comprehensive analysis which can assist researchers/developer quickly grasp relevant knowledge to assess a product and also providing new clues and ideas for future research.

RC48-Antibody-Drug Conjugate in Metastatic Urothelial Carcinoma: A Multicenter Real-World Study in China

OBJECTIVES

RC48 is an antibody-drug conjugate (ADC) that targets HER2. In China, RC48 is approved for patients with HER-2-positive metastatic urothelial carcinoma (mUC) who have failed at least platinum-based chemotherapy. This study aimed to evaluate RC48 for mUC in a cohort of real-world patients.

MATERIALS AND METHODS

We retrospectively collected data from 103 mUC patients from 12 centers between July 2021 and August 2023 in China. RC48 alone or with immunotherapy was administered until disease progression, intolerable toxicity, death, or other reasons. The objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and incidence of treatment-related adverse events (TRAEs) were evaluated.

RESULTS

The median age of the patients was 68 years, and 68.0% were men. Twenty-nine (28.2%) patients received RC48 alone; 73 (70.9%) received RC48 combination therapy. The response rates were as follows: complete response in 2 (1.9%) patients, partial response in 50 (48.5%) patients, stable disease in 30 (29.1%) patients. The ORR was 50.5%. In patients with ≥80 years, Eastern Cooperative Oncology Group (ECOG) performance status ≥2 and creatinine clearance rate (CCr) <30 mL/min, the ORR was 75%, 48.6%, and 40.0%, respectively. The median PFS was 6 (3.9-8.1) months, and the median OS was not reached. The most reported TRAEs were peripheral sensory neuropathy (53.4%), alopecia (42.7%), asthenia (38.8%), decreased appetite (35.9%) and weight loss (35.9%) and TRAE did not increase in patients with poor condition or impaired renal function.

CONCLUSION

Administration of RC48 for real-world patients is both effective and safe. mUC patients can benefit from RC48-based therapy, regardless of their poor condition or impaired renal function.

Disitamab Vedotin Alone or in Combination With Immune Checkpoint Inhibitors in Bladder-Sparing Treatment of Muscle-Invasive Bladder Cancer: A Real-World Study

PURPOSE

To evaluate the efficacy and safety of a novel humanized anti-HER2 antibody, RC48-ADC (Disitamab vedotin, DV), the combination of RC48-ADC with PD-1 inhibitors was used to treat muscle-invasive bladder cancer (MIBC). This combination therapy has potential applications in both bladder preservation and neoadjuvant therapy for MIBC.

METHODS

Patients with MIBC underwent transurethral resection of bladder tumors followed by RC48-ADC alone or in combination with PD-1 inhibitors. Radiological and endoscopic evaluations were conducted 3 months later. The primary endpoint was objective response rate (ORR), with secondary endpoints including complete response rate (CR), partial response rate (PR), and bladder preservation rate. Treatment safety was assessed according to RECIST v1.1 criteria.

RESULTS

Eleven patients were enrolled, with a median follow-up of 19.0 months. Nine patients achieved objective response, including 6 CR and 3 PR cases. The pathological ORR was 81.8%. Eight patients continued combined treatment after 3 months, maintaining a 72.7% bladder preservation rate at 16 months. One elderly patient progressed from ypT2N0M0 to ypT3N0M0 and underwent radical cystectomy but had no recurrence or metastasis 12 months postoperation. All patients reported varying degrees of treatment-related adverse reactions, which were largely manageable.

CONCLUSION

The combination of RC48-ADC and PD-1 inhibitors proves to be a viable and safe option for bladder-sparing therapy, particularly for T2-stage MIBC patients who are ineligible for surgery and chemotherapy. This approach offers a promising new direction for bladder preservation or neoadjuvant therapy in MIBC patients.

A review of the clinical efficacy of FDA-approved antibody‒drug conjugates in human cancers

While strategies such as chemotherapy and immunotherapy have become the first-line standard therapies for patients with advanced or metastatic cancer, acquired resistance is still inevitable in most cases. The introduction of antibody‒drug conjugates (ADCs) provides a novel alternative. ADCs are a new class of anticancer drugs comprising the coupling of antitumor mAbs with cytotoxic drugs. Compared with chemotherapeutic drugs, ADCs have the advantages of good tolerance, accurate target recognition, and small effects on noncancerous cells. ADCs occupy an increasingly important position in the therapeutic field. Currently, there are 13 Food and Drug Administration (FDA)‒approved ADCs and more than 100 ADC drugs at different stages of clinical trials. This review briefly describes the efficacy and safety of FDA-approved ADCs, and discusses the related problems and challenges to provide a reference for clinical work.

Antibody-drug conjugates in urothelial carcinoma: scientometric analysis and clinical trials analysis

In 2020, bladder cancer, which commonly presents as urothelial carcinoma, became the 10th most common malignancy. For patients with metastatic urothelial carcinoma, the standard first-line treatment remains platinum-based chemotherapy, with immunotherapy serving as an alternative in cases of programmed death ligand 1 expression. However, treatment options become limited upon resistance to platinum and programmed death 1 or programmed death ligand 1 agents. Since the FDA's approval of Enfortumab Vedotin and Sacituzumab Govitecan, the therapeutic landscape has expanded, heralding a shift towards antibody-drug conjugates as potential first-line therapies. Our review employed a robust scientometric approach to assess 475 publications on antibody-drug conjugates in urothelial carcinoma, revealing a surge in related studies since 2018, predominantly led by U.S. institutions. Moreover, 89 clinical trials were examined, with 36 in Phase II and 13 in Phase III, exploring antibody-drug conjugates as both monotherapies and in combination with other agents. Promisingly, novel targets like HER-2 and EpCAM exhibit substantial therapeutic potential. These findings affirm the increasing significance of antibody-drug conjugates in urothelial carcinoma treatment, transitioning them from posterior-line to frontline therapies. Future research is poised to focus on new therapeutic targets, combination therapy optimization, treatment personalization, exploration of double antibody-coupled drugs, and strategies to overcome drug resistance.

Drug conjugates for the treatment of lung cancer: from drug discovery to clinical practice

A drug conjugate consists of a cytotoxic drug bound via a linker to a targeted ligand, allowing the targeted delivery of the drug to one or more tumor sites. This approach simultaneously reduces drug toxicity and increases efficacy, with a powerful combination of efficient killing and precise targeting. Antibody‒drug conjugates (ADCs) are the best-known type of drug conjugate, combining the specificity of antibodies with the cytotoxicity of chemotherapeutic drugs to reduce adverse reactions by preferentially targeting the payload to the tumor. The structure of ADCs has also provided inspiration for the development of additional drug conjugates. In recent years, drug conjugates such as ADCs, peptide‒drug conjugates (PDCs) and radionuclide drug conjugates (RDCs) have been approved by the Food and Drug Administration (FDA). The scope and application of drug conjugates have been expanding, including combination therapy and precise drug delivery, and a variety of new conjugation technology concepts have emerged. Additionally, new conjugation technology-based drugs have been developed in industry. In addition to chemotherapy, targeted therapy and immunotherapy, drug conjugate therapy has undergone continuous development and made significant progress in treating lung cancer in recent years, offering a promising strategy for the treatment of this disease. In this review, we discuss recent advances in the use of drug conjugates for lung cancer treatment, including structure-based drug design, mechanisms of action, clinical trials, and side effects. Furthermore, challenges, potential approaches and future prospects are presented.

Research progress on novel antibody drug conjugates in cancer therapy

Traditional antibody drug conjugates (ADC) combine monoclonal antibodies with cytotoxic drugs to accurately strike cancer cells, but there are still many shortcomings in stability, targeting, efficacy, and safety. Novel ADC, such as bi-specific, site-specific, dual-payload, and pro-drug type ADC, can be optimized by simultaneously binding 2 different antigens or epitopes, selecting more stable linkers, coupling with specific amino acid sites of antibodies, carrying different drug payloads, and adopting prodrug strategies, while retaining the characteristics of traditional ADC. Significantly improving the stability, targeting, efficacy and safety of drugs can better meet the needs of clinical treatment. Novel ADC will play a more important role in cancer treatment in the future. Discussing the progress of novel ADC in cancer treatment and analyzing their advantages and challenges can provide theoretical support for the development of anti-cancer strategies and provide directions for drug research and development.

Expression of HER2 in high-grade urothelial carcinoma based on Chinese expert consensus and the clinical effects of disitamab vedotin-tislelizumab combination therapy in the treatment of advanced patients

Background: A vast number of researchers have discovered high levels of human epidermal growth factor receptor-2 (HER2) expression in urothelial carcinoma (UC), but they do not use a uniform scoring system. Based on the 2021 edition of clinical pathological expert consensus on HER-2 testing in UC in China, we investigated the expression level and clinical significance of HER2 in high-grade UC. Furthermore, we looked at the prognosis of patients with locally advanced/metastatic UC after combining HER2 targeting antibody-drug conjugates (ADC) medication disitamab vedotin (DV) with programmed cell death protein 1 (PD-1) inhibitor tislelizumab. Patients and methods: From 2019 to 2022, we collected paraffin specimens of UC from the Department of Urology at the Provincial Hospital Affiliated to Shandong First Medical University. HER2 expression-related factors were investigated. Patients with advanced UC who have failed systemic chemotherapy at least once and had received immune checkpoint inhibitor (ICI) medication during second-line treatment were selected and treated with DV in combination with tislelizumab. We assessed the therapy's efficacy and safety. Results: 185 patients with high-grade UC were included in this investigation. 127 patients (68.7%) were HER2 positive (IHC 2+/3+) according to the 2021 Clinical pathological expert consensus on HER2 testing in UC in China. The clinical stage of UC differed statistically significantly between the HER2-and HER2+ groups (p = 0.019). Sixteen advanced UC patients were treated with DV and tislelizumab for a median of 14 months. The disease control rate was 87.5%, while the objective response rate (ORR) was 62.5%. The ORR of HER2+ individuals was higher than that of HER2-individuals (70.0% vs. 50.0%). The median progression-free survival or overall survival was not reached. In this study, the incidence of treatment-related adverse events was 68.8% (11/16), with all of them being grade 1 or 2 adverse reactions. Conclusion: HER2 protein expressed at a high percentage in UC, and 68.7% patients expressed HER2 positive (IHC 2+/3+). HER2+ expression is positively correlated with higher clinical stage of UC. HER2 targeted ADC drug disitamab vedotin combining with PD-1 inhibitor tislelizumab has shown efficacy, safety and controllable adverse reactions in the treatment of advanced UC.

Targeting the EGFR/RAS/RAF signaling pathway in anticancer research: a recent update on inhibitor design and clinical trials (2020-2023)

INTRODUCTION

Recent years have seen significant strides in drug developmenttargeting the EGFR/RAS/RAF signaling pathway which is critical forcell growth and proliferation. Protein-protein interaction networksamong EGFR, RAS, and RAF proteins offer insights for drug discovery. This review discusses the drug design and development efforts ofinhibitors targeting these proteins over the past 3 years, detailingtheir structures, selectivity, efficacy, and combination therapy.Strategies to combat drug resistance and minimize toxicities areexplored, along with future research directions.

AREA COVERED

This review encompasses clinical trials and patents on EGFR, KRAS,and BRAF inhibitors from 2020 to 2023, including advancements indesign and synthesis of proteolysis targeting chimeras (PROTACs) forprotein degradation.

EXPERT OPINION

To tackle drug resistance, designing allosteric fourth-generationEGFR inhibitors is vital. Covalent, allosteric, or combinationaltherapies, along with PROTAC degraders, are key methods to addressresistance and toxicity in KRAS and BRAF inhibitors.

Research Progress of PD 1/PD L1 Inhibitors in the Treatment of Urological Tumors

Immune checkpoint inhibitors (ICIs) offer significant advantages for the treatment of urologic tumors, enhancing the immune function of anti-tumor T cells by inhibiting PD-1 and PDL1 binding. They have been shown to be well tolerated and remarkably effective in clinical practice, offering hope to many patients who are not well treated with conventional drugs. Clinical trials in recent years have shown that anti-PD-1 and PD-L1 antibodies have good efficacy and safety in the treatment of urologic tumors. These antibodies can be applied to a variety of urologic tumors, such as bladder cancer, renal cell carcinoma, and prostate cancer. They have been approved for the first-line treatment or as an option for follow-up therapy. By blocking the PD-1/PD-L1 signaling pathway, ICIs can release immune functions that are suppressed by tumor cells and enhance T-cell killing, thereby inhibiting tumor growth and metastasis. This therapeutic approach has achieved encouraging efficacy and improved survival for many patients. Although ICIs have shown remarkable results in the treatment of urologic tumors, some problems remain, such as drug resistance and adverse effects in some patients. Therefore, further studies remain important to optimize treatment strategies and improve clinical response in patients. In conclusion, PD-1/PD-L1 signaling pathway blockers have important research advances for the treatment of urologic tumors. Their emergence brings new hope for patients who have poor outcomes with traditional drug therapy and provides new options for immunotherapy of urologic tumors. The purpose of this article is to review the research progress of PD-1 and PD-L1 signaling pathway blockers in urologic tumors in recent years.

Efficacy and safety analysis of a HER2-targeting antibody-drug conjugate combined with immune checkpoint inhibitors in solid tumors: a real-world study

BACKGROUND

Disitamab Vedotin is a novel antibody-drug conjugate (ADC) drug targeting HER2, which has shown a potential synergistic effect between Disitamab Vedotin and immune checkpoint inhibitors (ICIs). Therefore, we plan to conduct a retrospective real-world study to evaluate the efficacy and safety of Disitamab Vedotin monotherapy or combined with ICIs in the treatment of advanced or metastatic solid tumors.

METHODS

This retrospective study involved patients with locally advanced or metastatic solid tumors who were treated with Disitamab Vedotin monotherapy or combined with ICIs at West China Hospital of Sichuan University from July 2019 to June 2023. The observation items included progression-free survival (PFS), overall survival (OS), objective response rate (ORR), disease control rate (DCR), and treatment-related adverse events (TRAEs).

RESULTS

This study included 49 patients, out of which 34 patients were treated with Disitamab Vedotin plus ICIs and 15 patients received Disitamab Vedotin alone. In all patients, the median PFS was 10 months. The 6-month and 1-year OS rates were 91.1% and 82.3%, respectively. Eighteen (36.7%) patients achieved a partial response, and sixteen (32.7%) patients had stable disease. The combination therapy of Disitamab Vedotin plus ICIs showed a higher ORR (44.1% vs. 20.0%) and a longer median PFS (14 vs. 8 months) compared to Disitamab Vedotin alone. The median PFS for patients expressed with HER2 2+/3+ was 10 months and was not reached for patients expressed with HER2 0/1+. Grade 3-4 TRAEs occurred in 14.7% of patients who received the combination treatment and in 26.7% of patients who received Disitamab Vedotin alone.

CONCLUSIONS

Our study showed that Disitamab-Vedotin-based treatment, alone or in combination with ICIs, exerted considerable prognosis and good tolerance in patients with locally advanced or metastatic solid tumors, regardless of the HER2 expression levels. Whether combination therapy with ICIs provides greater therapeutic benefits compared to monotherapy needs to be further explored through randomized controlled trials.

Real-world effectiveness and safety of RC48-ADC alone or in combination with PD-1 inhibitors for patients with locally advanced or metastatic urothelial carcinoma: A multicenter, retrospective clinical study

INTRODUCTION

Previous RC48 (Disitamab Vedotin) studies established that the safety and efficacy of RC48-antibody-drug conjugate (ADC), either alone or combined with toripalimab, for metastatic urothelial carcinoma (mUC) patients exhibiting human epidermal growth factor receptor 2 (HER2)-positive or even HER2-negative status after standard chemotherapy failure.

METHODS

With locally advanced or metastatic urothelial carcinoma (la/mUC), patients who received RC48-ADC monotherapy or a combination with programmed cell death protein 1 (PD-1) inhibitors between August 2021 and October 2022 were enrolled in this retrospective observational study to evaluate the real-world antitumor effectiveness and safety.

RESULTS

Among the 38 enrolled patients (29 males; median age 67.5 years [38-93]), 8 received RC48-ADC monotherapy, while 30 received combination therapy. Initially, 63.2% (24/38) of the patients had received ≥1 line of prior treatment, and 63.2% (24/38) had visceral metastasis. UC of the bladder represented the majority type in 68.4% (26/38) of cases. By the data cutoff in March 2023, the overall objective response rate (ORR) was 63.2% (95% CI, 47.1%-79.2%), with a disease control rate (DCR) of 89.5% (95% CI, 79.3%-99.7%). Median follow-up time was 10.6 months. The median progression-free survival (PFS) was 8.2 months (95% CI, 5.9-10.5), with a 6-month PFS rate of 63.2% and a 12-month PFS rate of 34.1%. Median overall survival (OS) was not reached, with a 12-month OS rate of 76.7%. The median duration of response was 7.3 months (95% CI, 4.6-10.0) among 24 patients evaluated as partial response (PR). The most common treatment-related adverse events (TRAEs) included anemia (71.1%), anorexia (57.9%), asthenia (52.6%), hypoesthesia (52.6%), bone marrow suppression (47.4%), alopecia (47.4%), nausea (44.7%), proteinuria (36.8%), vomiting (34.2%), and hypoalbuminemia (31.6%). No patient experienced TRAEs of Grade ≥3. One patient had an immune-related adverse event (irAE) of rash related to toripalimab.

CONCLUSIONS

Both as monotherapy and in combination with PD-1 inhibitors, RC48-ADC exhibits promising effectiveness and manageable safety profile for mUC patients in real-world settings.

The Evolving Landscape of Antibody-Drug Conjugates: In Depth Analysis of Recent Research Progress

Antibody-drug conjugates (ADCs) are targeted immunoconjugate constructs that integrate the potency of cytotoxic drugs with the selectivity of monoclonal antibodies, minimizing damage to healthy cells and reducing systemic toxicity. Their design allows for higher doses of the cytotoxic drug to be administered, potentially increasing efficacy. They are currently among the most promising drug classes in oncology, with efforts to expand their application for nononcological indications and in combination therapies. Here we provide a detailed overview of the recent advances in ADC research and consider future directions and challenges in promoting this promising platform to widespread therapeutic use. We examine data from the CAS Content Collection, the largest human-curated collection of published scientific information, and analyze the publication landscape of recent research to reveal the exploration trends in published documents and to provide insights into the scientific advances in the area. We also discuss the evolution of the key concepts in the field, the major technologies, and their development pipelines with company research focuses, disease targets, development stages, and publication and investment trends. A comprehensive concept map has been created based on the documents in the CAS Content Collection. We hope that this report can serve as a useful resource for understanding the current state of knowledge in the field of ADCs and the remaining challenges to fulfill their potential.

Disitamab Vedotin plus anti-PD-1 antibody show good efficacy in refractory primary urethral cancer with low HER2 expression: a case report

Primary urethral carcinoma (PUC) has a low incidence, but with high aggressiveness. Most of the patients are found in late stage, with poor prognosis. At present, chemotherapy is still the main treatment for metastatic PUC, but it has limited effect. Here, we report a case of metastatic PUC with low HER2 expression that developed disease progression after multiline therapy including chemotherapy, programmed death-1 (PD-1) inhibitors and multi-targeted receptor tyrosine kinase (RTK) inhibitor. After receiving Disitamab Vedotin(a novel antibody drug conjugate, ADC) and toripalimab (a PD-1 inhibitor), the patient achieved persistent PR, and the PFS exceeded 12 months up to now. Our report indicates that, despite the patient of metastatic PUC has low expression of HER2, it is still possible to benefit from Disitamab Vedotin combined with PD-1 inhibitor, which may reverse the drug resistance of PD-1 inhibitor and chemotherapy to a certain extent. But larger sample studies are needed to determine the efficacy of this treatment strategy and its impact on survival.