HER2 Expression Associated with Clinical Characteristics and Prognosis of Urothelial Carcinoma in a Chinese Population

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.

Phytochemicals as Chemo-Preventive and Therapeutic Agents Against Bladder Cancer: A Comprehensive Review

Bladder cancer has a high incidence worldwide and is characterized by a high recurrence rate, metastatic potential, and a significant socioeconomic burden. Conventional treatment modalities usually exhibit serious adverse complications, which also negatively affect patients' quality of life. In the context of exploring new treatment approaches with fewer side effects, the utilization of natural compounds as alternative and/or complementary therapeutic options seems appealing. In the present study, the potential use and effects of various bioactive phytochemicals, including curcumin, resveratrol, epigallocatechin, genistein, and several others, in bladder cancer treatment are thoroughly reviewed. A special focus is given to their potential to beneficially modulate important molecular signaling pathways and mechanisms affecting cell survival, proliferation, migration, and apoptosis, which play a crucial role in the pathogenesis of bladder cancer, such as the PI3K/AKT/mTOR, Ras/Raf/MEK/MAPK, Wnt/β-Catenin, Notch, Hedgehog, Hippo, JAK2/STAT3, and PAF/PAF-receptor pathways. Nevertheless, most studies have been conducted in cell cultures and animal models. Due to differences in genetics and metabolism, more clinical trials are needed to ensure the bio-efficacy of these phytochemicals in humans.

Efficacy and safety of disitamab vedotin in combination with immune checkpoint inhibitors in patients with locally advanced or metastatic urothelial carcinoma

INTRODUCTION

Disitamab Vedotin (DV, RC48, or RC48-ADC) is a novel humanized antibody-drug conjugate (ADC), which is based on human epidermal growth factor receptor 2 antibody (anti-HER2, or hertuzumab) coupled with monomethyl auristatin E (MMAE). This study aims to evaluate the efficacy and safety of RC48-ADC in combination with programmed cell death protein 1 (PD-1) inhibitors for treatment of locally advanced or metastatic urothelial carcinoma (la/mUC) patients.

PATIENTS AND METHODS

This is a retrospective and real-world investigation originated from an enrollment of locally advanced or mUC patients underwent treatments with RC48-ADC in combination with PD-1 inhibitors in two hospitals, between August 2022 and July 2024. The overall objective response rate (ORR), disease control rate (DCR), median overall survival (mOS), median Progression Free Survival (mPFS) and safety were assessed.

RESULTS

Totally 51 locally advanced or mUC patients were included in this study, with the following background: age range (39-86 years old), gender (39 (76.5%) male, 12 (23.5%) female). Treatment outcomes included complete remission (27.5%), partial remission (33.3%), stable disease (13.7%), and disease progression (25.5%), yielding an ORR of 61% (95% CI:47-73%) and DCR of 75% (95% CI:61-84%). Until July 2024, the median overall survival (mOS) for all patients was not reached, the median progression-free survival (mPFS) for all patients was 9 months (95% CI:5.8-12.1).Treatment-related adverse events occurred in all patients and the most common side effects were anorexia, asthenia, rash, and pruritus. These adverse symptoms were readily manageable and could be relieved by symptomatic treatment.

CONCLUSION

RC48-ADC in combination with PD-1 immunotherapy has promising efficacy and manageable safety for locally advanced or mUC patients in real-world settings.

Disitamab vedotin plus toripalimab in patients with locally advanced or metastatic urothelial carcinoma (RC48-C014): a phase Ib/II dose-escalation and dose-expansion study

BACKGROUND

Human epidermal growth factor receptor 2 (HER2)-targeted antibody-drug conjugates (ADCs) such as disitamab vedotin (DV) and trastuzumab deruxtecan (T-DXd) have emerged as effective treatment options and received regulatory approvals for HER2-expressing locally advanced or metastatic urothelial carcinoma (la/mUC). In addition, ADCs in combination with immunotherapy have demonstrated antitumor activity. The current study aimed to evaluate the combination of DV and toripalimab in patients with la/mUC.

PATIENTS AND METHODS

This open-label phase Ib/II study enrolled patients with untreated or chemo-refractory la/mUC. During the dose-escalation phase, DV was administered at escalating doses of 1.5 and 2.0 mg/kg in combination with toripalimab 3.0 mg/kg once every 2 weeks. Primary endpoints were safety and the recommended phase II dose (RP2D). Secondary endpoints included objective response rate (ORR), progression-free survival (PFS), and overall survival (OS).

RESULTS

From August 2020 to December 2021, a total of 41 patients were enrolled, including 6 in the dose-escalation phase and 35 in the dose-expansion phase. Sixty-one percent of patients were treatment naive. No dose-limiting toxicity was observed. The RP2D was determined as DV (2.0 mg/kg) plus toripalimab (3.0 mg/kg). By the data cut-off date of 1 March 2024, the confirmed ORR was 73.2%. The median PFS was 9.3 months, and the median OS was 33.1 months. The most common treatment-related adverse events (TRAEs) were aspartate aminotransferase increased (65.9%), alanine aminotransferase increased (63.4%), and peripheral sensory neuropathy (63.4%). Grade 3 or higher TRAEs occurred in 51.2% of patients, with the most common being γ-glutamyltransferase increased (12.2%), asthenia (9.8%), and alanine aminotransferase increased (7.3%). One treatment-related death (due to pneumonitis) was reported.

CONCLUSIONS

The combination of DV and toripalimab demonstrated promising response rate and OS results with a manageable safety profile in HER2-unselected la/mUC patients. This combination represents a promising first-line option for la/mUC. Randomized phase III study is currently ongoing.

Disitamab vedotin vs. gemcitabine-cisplatin regimen with immunotherapy: a comparative analysis of efficacy and safety in muscle-invasive bladder cancer

Introduction

Muscle-invasive bladder cancer (MIBC) is an aggressive bladder cancer characterized by invasion of the muscular bladder wall, often necessitating a multimodal treatment approach for optimal outcomes. This study aimed to compare the real-world efficacy and safety of disitamab vedotin (RC48), an antibody-drug conjugate (ADC), combined immunotherapy targeting programmed cell death protein-1 (PD-1), against the gemcitabine and cisplatin (GC) regimen with PD-1 immunotherapy in the treatment of MIBC.

Methods

This single-center, retrospective study was conducted at the First Affiliated Hospital of Soochow University and included 38 patients with MIBC treated with either RC48 plus immunotherapy or GC regimen plus immunotherapy, between January 2022 and December 2023. Patients were divided into two groups: the RC48 with immunotherapy (ADC + PD-1) group and the GC regimen with immunotherapy (GC + PD-1) group. Efficacy was evaluated based on their pathological complete response rates (PCRR) and pathological downstaging rates (PDR). Adverse events (AEs) were assessed to compare safety profiles.

Results

Of the 38 patients, 17 were in the ADC + PD-1 group and 21 were in the GC + PD-1 group. The PCRR was significantly higher in the ADC + PD-1 group (82.35%, 14/17) compared to the GC + PD-1 group (47.62%, 10/21; P = 0.043). The PDR was also higher in the ADC + PD-1 group (94.12%, 16/17) than in the GC + PD-1 group (80.95%, 17/21), although the difference was not statistically significant (P = 0.355). No serious allergic reactions or fatal AEs were reported in either group. No Grade 4 AEs were reported, while Grade 3 AEs occurred at a rate of 5.71% in the ADC + PD-1 group and 12.20% in the GC + PD-1 group (P = 0.260).

Conclusion

RC48 combined with immunotherapy demonstrated a significantly higher PCRR compared to the GC regimen with immunotherapy, while maintaining a comparable safety profile. These findings highlight the potential of RC48 combined with immunotherapy as an effective treatment option for MIBC in clinical practice.

Noninvasive identification of HER2 status by integrating multiparametric MRI-based radiomics model with the vesical imaging-reporting and data system (VI-RADS) score in bladder urothelial carcinoma

PURPOSE

HER2 expression is crucial for the application of HER2-targeted antibody-drug conjugates. This study aims to construct a predictive model by integrating multiparametric magnetic resonance imaging (mpMRI) based multimodal radiomics and the Vesical Imaging-Reporting and Data System (VI-RADS) score for noninvasive identification of HER2 status in bladder urothelial carcinoma (BUC).

METHODS

A total of 197 patients were retrospectively enrolled and randomly divided into a training cohort (n = 145) and a testing cohort (n = 52). The multimodal radiomics features were derived from mpMRI, which were also utilized for VI-RADS score evaluation. LASSO algorithm and six machine learning methods were applied for radiomics feature screening and model construction. The optimal radiomics model was selected to integrate with VI-RADS score to predict HER2 status, which was determined by immunohistochemistry. The performance of predictive model was evaluated by receiver operating characteristic curve with area under the curve (AUC).

RESULTS

Among the enrolled patients, 110 (55.8%) patients were demonstrated with HER2-positive and 87 (44.2%) patients were HER2-negative. Eight features were selected to establish radiomics signature. The optimal radiomics signature achieved the AUC values of 0.841 (95% CI 0.779-0.904) in the training cohort and 0.794 (95%CI 0.650-0.938) in the testing cohort, respectively. The KNN model was selected to evaluate the significance of radiomics signature and VI-RADS score, which were integrated as a predictive nomogram. The AUC values for the nomogram in the training and testing cohorts were 0.889 (95%CI 0.840-0.938) and 0.826 (95%CI 0.702-0.950), respectively.

CONCLUSION

Our study indicated the predictive model based on the integration of mpMRI-based radiomics and VI-RADS score could accurately predict HER2 status in BUC. The model might aid clinicians in tailoring individualized therapeutic strategies.

Clinical significance of HER2 in urothelial carcinoma and analysis of its correlation with glycolytic metabolic characteristics

Objective

This study aimed to explore the clinical relevance of Human Epidermal Growth Factor Receptor 2 (HER2) in urothelial carcinoma (UC) and its association with glycolytic metabolic markers, insulin resistance, and beta-cell function, shedding light on potential therapies targeting both HER2 pathways and cancer metabolism.

Methods

In this retrospective analysis, 237 UC patients from the Departments of Urology and Pathology at Shandong Provincial Hospital were examined. From 1 January 2023, to 1 October 2024, patients underwent HER2 testing using immunohistochemistry (IHC). We investigated the relationships between HER2 expression and metabolic indicators such as the Homeostatic Model Assessment for insulin resistance (HOMA-IR), beta-cell function (HOMA-β), the triglyceride-glucose (TyG) index, and lactate dehydrogenase (LDH) levels. HER2 status was determined using a standardized scoring system from the 2021 Clinical Pathological Expert Consensus on HER2 Testing in UC, China. Statistical analysis followed CDC guidelines, using multivariate logistic regression to assess the independent impacts of HER2 on metabolic traits.

Results

Of the 237 evaluated UC samples, 87.76% exhibited positive HER2 expression. A significant correlation was found between positive HER2 status, advanced tumor stages, and increased LDH levels, suggesting a link between HER2 expression and heightened glycolytic activity. No significant relationships were observed between HER2 status and TyG levels, HOMA-IR, or HOMA-B. Subgroup analyses confirmed the consistency of the relationship between HER2 expression and LDH levels across different demographics and lifestyle factors.

Conclusion

Our findings confirm the significant role of HER2 as a prognostic marker and therapeutic target in UC. The association of HER2 positivity with advanced tumor stages and high LDH levels underscores its complex involvement in disease progression. This study highlights the need to explore HER2's biological mechanisms further and pursue combined therapeutic strategies.

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.

Phase 2 Trial of Enfortumab Vedotin in Patients With Previously Treated Locally Advanced or Metastatic Urothelial Carcinoma in China

BACKGROUND

Enfortumab vedotin, a fully human monoclonal antibody-drug conjugate (ADC) directed to Nectin-4, prolonged overall survival (OS) versus standard chemotherapy in patients with previously treated locally advanced or metastatic urothelial carcinoma (mUC) previously receiving a programmed cell death protein 1/ligand 1 (PD-1/L1) inhibitor and platinum-based chemotherapy in the pivotal, phase 3 EV-301 clinical trial, supporting global approvals of enfortumab vedotin monotherapy. This bridging study was the first to evaluate enfortumab vedotin monotherapy in previously treated Chinese patients with locally advanced or mUC.

METHODS

EV-203 was a multicenter, open-label, phase 2 study (NCT04995419) assessing efficacy, safety/tolerability, pharmacokinetics (PK), and immunogenicity of enfortumab vedotin in 40 Chinese patients (PK analysis set, n = 13) with previously treated locally advanced or mUC. Patients received enfortumab vedotin 1.25 mg/kg (Days 1, 8, and 15). Primary endpoints included confirmed objective response rate (ORR) by the independent review committee (IRC) and PK parameters of ADC, total antibody (TAb), and free monomethyl auristatin E (MMAE). Secondary endpoints included investigator-assessed confirmed ORR; investigator-/IRC-assessed duration of response (DOR), disease control rate (DCR), and progression-free survival (PFS); OS; immunogenicity; and safety/tolerability.

RESULTS

As of May 13, 2022, the median follow-up was 6.5 months. Confirmed ORR was 37.5% (n/N = 15/40; 95% CI: 22.7%-54.2%) by IRC and 42.5% (n/N = 17/40; 95% CI: 27.0%-59.1%) by investigator assessment. By IRC, DCR was 72.5% (n = 29), median DOR was not reached, and median PFS was 4.7 months. Median OS was not reached. Endpoints assessed by investigators were consistent with IRC assessments. Two patients discontinued treatment for treatment-related adverse events. No new safety signals were identified. ADC, TAb, and free MMAE were characterized in Chinese patients and consistent with previously characterized populations. The incidence of positive antitherapeutic antibodies postbaseline was 0%.

CONCLUSION

Enfortumab vedotin demonstrated meaningful clinical activity with a manageable safety profile in Chinese patients with previously treated locally advanced or mUC.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04995419.

Disitamab vedotin (RC48) long-term regimen in a post-nephroureterectomy patient with metastases: a case report

Background

For patients with metastatic upper tract urothelial carcinoma (UTUC), the preferred first-line treatment is platinum-based chemotherapy. Immunotherapy can be considered a subsequent treatment if the chemotherapy is ineffective or the disease progresses. However, how should treatment be administered if immunotherapy is useless and the patient cannot take chemotherapy? Especially in patients who have metastasized after radical nephroureterectomy (RNU).

Case presentation

A 68-year-old woman was admitted to the hospital due to left flank pain for two weeks and was diagnosed with metastatic UTUC after RNU. The patient underwent systemic chemotherapy with gemcitabine and cisplatin (GC), as well as reduced-dose GC, but developed myelosuppression. Immunotherapy was ineffective, so Disitamab vedotin (RC48) was chosen.

Results

Disitamab vedotin (RC48) monotherapy was administered for 13 cycles, during which thyroid function remained normal, the patient responded well to the treatment, and the disease was controlled well. In the subsequent two years of follow-up, there was no disease recurrence.

Conclusion

The long-term treatment regimen with RC48 is feasible for metastatic UTUC after RNU, and RC48 monotherapy is suitable as first-line therapy for selected patients.

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.

Effects of trastuzumab emtansine on canine urothelial carcinoma cells in vitro and in vivo

Urothelial carcinoma (UC) is the most common malignancy of the urinary tract in dogs and has aggressive behaviour. Although human epidermal growth factor receptor 2 (HER2) is a known therapeutic target with evidence in canine UC, the efficacy of anti-HER2 antibody drugs remains unknown. This study aimed to investigate the effects of anti-HER2 antibody drugs including trastuzumab and trastuzumab emtansine (T-DM1) on canine UC cell lines in vitro and in vivo. Four canine UC cell lines (Nene, TCCUB, Love, and Sora) were used. In western blotting, HER2 protein expression was observed in all the cell lines. Although both trastuzumab and T-DM1 showed dose-dependent growth inhibitory activity in the cell lines, T-DM1 showed much stronger activity than that of trastuzumab. In flow cytometry analyses with the canine UC cell line (Sora), T-DM1 but not trastuzumab significantly increased the percentages of early and late apoptotic cells in annexin V apoptotic assays and the sub-G1 phase fraction in cell cycle analyses. For the in vivo experiment, the canine UC cells (Sora) were subcutaneously injected into nude mice. Four days after inoculation, trastuzumab, T-DM1, or vehicle was administered intraperitoneally once a week for three times. Tumour volumes were significantly smaller in the T-DM1 group compared to the trastuzumab and vehicle control groups. These findings indicate that T-DM1 exerts a stronger antitumour effect than that of trastuzumab on canine UC cells in vitro and in vivo, possibly by inducing apoptosis due to DM1.

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.

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.