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.

Exploring membranous NECTIN-4 expression patterns and enfortumab vedotin response in prostate cancer.

Antibody-drug conjugates (ADCs) represent a novel type of targeted cancer therapy combining the specificity of monoclonal antibodies with the cytotoxicity of conventional chemotherapy. Recently, ADCs have demonstrated practice-changing efficacy across diverse solid cancers. The anti-NECTIN-4 ADC enfortumab vedotin (EV) has just been approved for patients with urothelial cancer and is currently under investigation for patients with castration-resistant prostate cancer (CRPC e.g. Phase II ENCORE trial). Our objective was to evaluate the efficacy of EV in established prostate cancer (PCa) cell lines and to examine the membranous NECTIN-4 expression in primary tumours (PRIM) and distant metastases (MET). NECTIN-4 was heterogeneously expressed in the panel of PCa cell lines. EV led to growth inhibition in NECTIN-4 expressing PCa cells (22Rv1 and LNCaP), whereas the NECTIN-4-negative PC-3 cells were significantly less responsive to EV, emphasizing the dependence of EV response on its target expression. Immunohistochemical staining revealed moderate membranous NECTIN-4 expression only in a small subgroup of CRPC patients with lung and peritoneal MET [n = 3/22 with H-score ≥100, median H-score 140 (IQR 130-150)], while 100% of PRIM (n = 48/48) and 86.4% of common MET sites (n = 19/22), including lymph node, bone and liver MET, were NECTIN-4 negative. In summary, EV may be effective in NECTIN-4-positive PCa. However, our findings demonstrate that the tumoural NECTIN-4 expression is predominantly low in metastatic PCa, which suggests that EV may only be effective in a biomarker-stratified subgroup.

The Double Antibody Drug Conjugate (DAD) phase I trial: sacituzumab govitecan plus enfortumab vedotin for metastatic urothelial carcinoma.

BACKGROUND: The antibody-drug conjugates sacituzumab govitecan (SG) and enfortumab vedotin (EV) are standard monotherapies for metastatic urothelial carcinoma (mUC). Given the different targets and payloads, we evaluated the safety and efficacy of SG + EV in a phase I trial in mUC (NCT04724018). PATIENTS AND METHODS: Patients with mUC and Eastern Cooperative Oncology Group performance status ≤1 who had progressed on platinum and/or immunotherapy were enrolled. SG + EV were administered on days 1 + 8 of a 21-day cycle until progression or unacceptable toxicity. Primary endpoint was the incidence of dose-limiting toxicities during cycle 1. The number of patients treated at each of four pre-specified dose levels (DLs) and the maximum tolerated doses in combination (MTD) were determined using a Bayesian Optimal Interval design. Objective response, progression-free survival, and overall survival were secondary endpoints. RESULTS: Between May 2021 and April 2023, 24 patients were enrolled; 1 patient never started therapy and was excluded from the analysis. Median age was 70 years (range 41-88 years); 11 patients received ≥3 lines of therapy. Seventy-eight percent (18/23) of patients experienced grade ≥3 adverse event (AE) regardless of attribution at any DL, with one grade 5 AE (pneumonitis possibly related to EV). The recommended phase II doses are SG 8 mg/kg with EV 1.25 mg/kg with granulocyte colony-stimulating factor support; MTDs are SG 10 mg/kg with EV 1.25 mg/kg. The objective response rate was 70% (16/23, 95% confidence interval 47% to 87%) with three complete responses; three patients had progressive disease as best response. With a median follow-up of 14 months, 9/23 patients have ongoing response including 6 responses lasting over 12 months. CONCLUSIONS: The combination of SG + EV was assessed at different DLs and a safe dose for phase II was identified. The combination had encouraging activity in patients with mUC with high response rates, including clinically significant complete responses. Additional study of this combination is warranted.

A plain language summary exploring a new treatment combination for untreated locally advanced or metastatic urothelial cancer: enfortumab vedotin plus pembrolizumab.

WHAT IS THIS SUMMARY ABOUT?: This summary provides the results of a study of two treatments for cancer, enfortumab vedotin and pembrolizumab, that were studied together against locally advanced or metastatic urothelial cancer (la/mUC), a cancer that occurs most commonly in the bladder. WHAT WERE THE RESULTS?: In the 45 patients studied, around 16% did have serious side effects, but most side effects were manageable. Twenty-four percent of patients, however, stopped the study treatment because of their side effects. Within about 2 months of starting treatment, most patients' (73%) tumors were smaller and stayed smaller, on average, for more than 2 years. WHAT DO THE RESULTS MEAN?: The combination of enfortumab vedotin plus pembrolizumab is a new treatment option for patients with locally advanced or metastatic urothelial cancer when they cannot receive the typical treatment, cisplatin. Advanced or metastatic urothelial cancer is a type of cancer where the cancer has already spread outside of the bladder or urinary tract.

Nectin-4 expression in a subset of cutaneous adnexal carcinomas: A potential target for therapy with enfortumab vedotin.

BACKGROUND: Enfortumab vedotin (EV) is an antibody-drug conjugate directed against Nectin-4 that is used to treat urothelial carcinoma. Nectin-4 is inherently expressed in the skin and adnexal structures. Since therapeutic options for cutaneous adnexal carcinomas are limited, we sought to evaluate Nectin-4 expression in adnexal carcinomas and benign adnexal neoplasms to identify tumors that are potentially targetable with EV. METHODS: Eight sebaceous carcinomas (seven periocular and one lymph node metastasis), eight digital papillary adenocarcinomas, seven squamoid eccrine ductal carcinomas, eight poromas, eight trichilemmomas, and seven sebaceous adenomas were subjected to immunohistochemical staining for anti-Nectin-4 antibody. H-scores for Nectin-4 expression were calculated. RESULTS: Benign adnexal neoplasms had a significantly lower mean (±SD) Nectin-4 H-score (142.6 ± 39.1) than did the adnexal carcinomas (198 ± 90.8; p = 0.006). Nectin-4 was expressed in 91% (21/23) of adnexal carcinomas. Sebaceous carcinomas frequently exhibited high expression of Nectin-4 (88% [7/8]), with a mean (±SD) H-score (258.1 ± 58.4) significantly higher than those for digital papillary adenocarcinomas (197.5 ± 52.5; p = 0.035) and squamoid eccrine ductal carcinomas (131.4 ± 114.1; p = 0.031). Sebaceous carcinomas also had significantly higher H-scores than did sebaceous adenomas (186.4 ± 25.0; p = 0.013). CONCLUSIONS: Increased Nectin-4 expression in a subset of cutaneous adnexal carcinomas, particularly sebaceous carcinomas, reveals that EV is a potential therapeutic option for these tumors.

Trend in overall survival from the start of first-line chemotherapy in patients with metastatic urothelial carcinoma.

New approaches involving immune checkpoint inhibitors and antibody-drug conjugates prolong overall survival in patients with metastatic urothelial carcinoma. However, the access to such systemic therapy in clinical practice is suboptimal, and whether these agents improve overall survival in patients with metastatic urothelial carcinoma over time remains unclear. Hence, we investigated the overall survival trend from the initiation of first-line therapy with these agents to identify changes due to the medication and time of treatment initiation. We retrospectively evaluated 195 patients from a single center. They were treated with chemotherapy, pembrolizumab, or avelumab or enfortumab vedotin. The treatment was categorized into chemotherapy, pembrolizumab or avelumab/enfortumab vedotin period. The new agents prolonged overall survival from the start of first-line therapy. Furthermore, sequential treatment with these agents in real-world clinical practice has been reported to prolong overall survival. These study results will have major implications when a new first-line therapy is approved in the future.

Association between response to enfortumab vedotin and peripheral neuropathy in urothelial carcinoma patients: a multicenter retrospective study.

BACKGROUND: Enfortumab vedotin (EV) was approved for patients with metastatic urothelial carcinoma (mUC) who progressed after anticancer therapy on September 2021 in Japan. The association between the occurrence of EV-related side effects and clinical outcome remains to be elucidated. METHODS: We identified 97 mUC patients treated with EV therapy at our five institutions from the date of approval to March 2023. The median follow-up period was 7.0 months. We retrospectively analyzed the efficacy and safety of EV. RESULTS: The median age of the patients was 71 years old, 39% had PS of 1 or more, and 56.7% had primary tumor in upper urinary tract. Overall response rate (ORR) to EV therapy, median progression-free survival (PFS), and overall survival (OS) were 43.3%, 7.52 months, and 12.78 months, respectively. Any grade of treatment-related skin disorder, dysgeusia, peripheral neuropathy, gastrointestinal disorder, and hyperglycemia occurred in 61 (62.9%), 36 (37.1%), 34 (35.1%), 29 (29.9%), and 18 (18.6%) patients, respectively. The patients with EV-associated peripheral neuropathy had significantly higher ORR (58.8% vs. 34.9%, P = .032) and longer median PFS (8.05 vs. 6.31 months, P = .017) and OS (not reached vs. 11.57 months, P = .008, respectively) than those without. The occurrence of peripheral neuropathy after EV treatment and the presence of peritoneal dissemination were factors independently associated with PFS (hazard ratio = 0.46, P = .008 and hazard raito = 3.83, P = .004, respectively) and OS (hazard ratio = 0.30, P = .005 and hazard raito = 4.53, P = .002, respectively). CONCLUSIONS: The occurrence of EV-related peripheral neuropathy might be associated with the efficacy of EV therapy in mUC patients.

Latest evidence on clinical outcomes and prognostic factors of advanced urothelial carcinoma in the era of immune checkpoint inhibitors: a narrative review.

The management of advanced (locally advanced or metastatic) urothelial carcinoma has been revolutionized since pembrolizumab was introduced in 2017. Several prognostic factors for advanced urothelial carcinoma treated with pembrolizumab have been reported, including conventional parameters such as performance status and visceral (especially liver) metastasis, laboratory markers such as the neutrophil-to-lymphocyte ratio, sarcopenia, histological/genomic markers such as programmed cell death ligand 1 immunohistochemistry and tumor mutational burden, variant histology, immune-related adverse events, concomitant medications in relation to the gut microbiome, primary tumor site (bladder cancer versus upper tract urothelial carcinoma) and history/combination of radiotherapy. The survival time of advanced urothelial carcinoma has been significantly prolonged (or 'doubled' from 1 to 2 years) after the advent of pembrolizumab, which will be further improved with novel agents such as avelumab and enfortumab vedotin. This review summarizes the latest evidence on clinical outcomes and prognostic factors of advanced urothelial carcinoma in the contemporary era of immune checkpoint inhibitors.

Enfortumab vedotin following platinum-based chemotherapy and immune checkpoint inhibitors for advanced urothelial carcinoma: response, survival and safety analysis from a multicentre real-world Japanese cohort.

OBJECTIVE: Real-world evidence regarding enfortumab vedotin for unresectable or metastatic urothelial carcinoma is scarce, particularly in Japan. We investigated real-world data focusing on patient background, previous treatments, response, survival and adverse events in patients receiving enfortumab vedotin. METHODS: A multicentre database was used to register 556 patients diagnosed with metastatic urothelial carcinoma from 2008 to 2023; 34 patients (6.1%) treated with enfortumab vedotin were included. Best radiographic objective responses were evaluated using the Response Evaluation Criteria in Solid Tumors (v1.1) during treatments. Overall survival and progression-free survival were estimated (Kaplan-Meier method). Toxicities were reported according to the Common Terminology Criteria for Adverse Events, version 5.0. The relative dose intensity, which could impact oncological outcomes, was calculated. RESULTS: The median number of enfortumab vedotin therapy cycles was 5. The best objective response to enfortumab vedotin was partial response, stable disease and progressive disease in 19 (56%), 5 (15%) and 10 (29%) patients, respectively. The median overall survival and progression-free survival after the first enfortumab vedotin dose were 16 and 9 months, respectively. No significant relationship was observed between survival outcomes after enfortumab vedotin initiation and the enfortumab vedotin relative dose intensity. The median overall survival from first-line platinum-based chemotherapy initiation was 42 months. Twenty-six (76%) patients experienced any grade of enfortumab vedotin-related toxicities; eight (24%) experienced Grades 3-4 toxicities, the most common being skin toxicity (any grade, 47%; Grades 3-4, 12%). CONCLUSIONS: Here, we report real-world evidence for enfortumab vedotin therapy in Japan. Tumour responses and safety profiles were comparable with those of clinical trials on this novel treatment.

Therapeutic efficacy and safety of biweekly administration of enfortumab vedotin for urothelial carcinoma.

OBJECTIVES: Enfortumab vedotin (EV) is an established pharmacotherapy for metastatic urothelial carcinoma (mUC); however, its adverse events (AEs) cannot be overlooked. The study investigated the efficacy and safety of biweekly EV administration. METHODS: Patients with mUC who received EV at our institution were included in the study. Eligible patients were classified into two groups as follows: those who received EV on a standard schedule (standard group) and those who received EV on a biweekly schedule (biweekly group); the treatment outcomes and AEs between the two groups were compared. RESULTS: Nine and 19 patients were in the standard group and biweekly groups, respectively. The progression-free survival, overall survival, and overall response rate were not significantly different between the two groups. AEs following EV administration, such as decreased appetite (P < .01), pruritus (P < .01), rash maculopapular (P < .01), anemia (P = .04), and liver dysfunction (P = .04), were significantly more frequent in the standard group. Grade 3 or higher AEs, such as pruritus (P = .03) and rash maculopapular (P < .01), were significantly more frequent in the standard group. Furthermore, significantly more patients in the standard group had to be given a reduced dose due to adverse events (P = .02). CONCLUSIONS: Biweekly administration of EV may be safer without compromising therapeutic efficacy than the standard schedule.

Peripheral neuropathy and nerve electrophysiological changes with enfortumab vedotin in patients with advanced urothelial carcinoma: a prospective multicenter cohort study.

BACKGROUND: Enfortumab vedotin is a novel antibody-drug conjugate used as a third-line therapy for the treatment of urothelial cancer. We aimed to elucidate the effect of enfortumab vedotin-related peripheral neuropathy on its efficacy and whether enfortumab vedotin-induced early electrophysiological changes could be associated with peripheral neuropathy onset. METHODS: Our prospective multicenter cohort study enrolled 34 patients with prior platinum-containing chemotherapy and programmed cell death protein 1/ligand 1 inhibitor-resistant advanced urothelial carcinoma and received enfortumab vedotin. The best overall response, progression-free survival, overall survival, and safety were assessed. Nerve conduction studies were also performed in 11 patients. RESULTS: The confirmed overall response rate and disease control rate were 52.9% and 73.5%, respectively. The median overall progression-free survival and overall survival were 6.9 and 13.5 months, respectively, during a median follow-up of 8.6 months. The patients with disease control had significantly longer treatment continuation and overall survival than did those with uncontrolled disease. Peripheral neuropathy occurred in 12.5% of the patients. The overall response and disease control rates were 83.3% and 100%, respectively: higher than those in patients without peripheral neuropathy (p = 0.028 and p = 0.029, respectively). Nerve conduction studies indicated that enfortumab vedotin reduced nerve conduction velocity more markedly in sensory nerves than in motor nerves and the lower limbs than in the upper limbs, with the sural nerve being the most affected in the patients who developed peripheral neuropathy (p = 0.011). CONCLUSION: Our results indicated the importance of focusing on enfortumab vedotin-induced neuropathy of the sural nerve to maximize efficacy and improve safety.

Enfortumab-vedotin use for urothelial carcinoma in two patients on hemodialysis.

Enfortumab vedotin (EV) is a novel treatment option for patients with advanced/metastatic urothelial carcinoma who have progressed after chemotherapy and immunotherapy. Two patients at two different New England tertiary cancer care centers were treated with EV while concurrently receiving hemodialysis (HD), where a complete response to EV in both patients was noted. The use of EV in patients requiring HD is extrapolated from the available pharmacokinetic and pharmacodynamic literature on monoclonal antibodies in patients requiring HD. There is a paucity of data for the use of antibody-drug conjugates like EV in patients needing dialysis.

Enfortumab vedotin prolongs overall survival in metastatic urothelial carcinoma following pembrolizumab therapy in real-world data.

OBJECTIVE: In December 2021, enfortumab vedotin (EV), an antibody-drug conjugate directed against nectin-4, was approved in Japan as a new treatment after platinum-containing chemotherapy and PD-1/PD-L1 inhibitors. This study evaluated, using real-world data, the efficacy and safety of EV therapy in patients with metastatic urothelial carcinoma (mUC). MATERIALS AND METHODS: Fifty-five patients with mUC who discontinued pembrolizumab therapy due to disease progression between June 2018 and April 2023 at Yokohama City University Hospital were evaluated retrospectively. Of the 55 patients, 25 received EV therapy (EV group) and 30 did not (non-EV group). All patients who underwent EV therapy were diagnosed with disease progression after the approval of EV in Japan. RESULTS: The median (range) follow-up period after pembrolizumab discontinuation was 6.3 (0.7-31.1) months. There were eight (32.0%) deaths due to cancer in the EV group and 27 (90.0%) in the non-EV group. The overall survival (OS) after pembrolizumab discontinuation was not reached in the EV group versus 2.6 months in the non-EV group (p < 0.001). A multivariate analysis revealed that EV therapy (EV vs. non-EV group; hazard ratio 0.26; 95% confidence interval 0.16-0.41; p < 0.001) was an independent prognostic factor for OS. CONCLUSION: EV prolonged OS in mUC following pembrolizumab therapy in real-world data.

Real world evidence of enfortumab vedotin in patients with advanced urothelial cancer: A multicenter observational study.

OBJECTIVES: To explore the characteristics of patients and assess the effectiveness of enfortumab vedotin (EV) in those with treatment-resistant advanced urothelial cancer in a real-world setting. PATIENTS AND METHODS: A multicenter observational study was conducted on 103 evaluable patients with advanced urothelial cancer who received EV. Outcomes were assessed by radiographic response, progression-free survival (PFS), and overall survival (OS), with treatment-related adverse events (trAEs). Radiographic response was assessed using Response Evaluation Criteria in Solid Tumors version 1.1, while trAEs were studied in line with Common Terminology Criteria for Adverse Events version 5.0. RESULTS: The median follow-up was 8.9 months (range, 0.1-16.4). The observed objective response rate was 50.5%. The median PFS was 6.0 months (95% CI: 4.7-9.8), and the median OS was 14.5 months (95% CI: 12.4-not reached). Out of the 103 patients, 19 (18.4%) had an Eastern Cooperative Oncology Group performance status of 2 or more, 14 (14.7%) had an non-urothelial carcinoma histology, and 40 (38.3%) had at least one pre-existing comorbidity. There were 26 (25.2%) patients who reported 49 trAEs, with 9 (18.3%) being grade 3 or higher. The most common trAEs included rash, occurring in 18.4%. CONCLUSIONS: This study describes the characteristics and outcomes of patients with previously treated advanced urothelial cancer receiving EV. The findings demonstrate that EV showed robust anti-tumor activity and had manageable safety profiles outside the clinical trial setting.

Real-world sequential treatment patterns and clinical outcomes among patients with advanced urothelial carcinoma in Japan.

OBJECTIVES: Immune checkpoint inhibitors and enfortumab vedotin have opened new avenues for sequential treatment strategies for locally advanced/metastatic urothelial carcinoma (la/mUC). In the pre-enfortumab vedotin era, many patients could not receive third-line treatment owing to rapid disease progression and poor general status. This study aimed to analyze real-world sequential treatment practices for la/mUC in Japan, with a focus on patients who do not receive third-line treatment. METHODS: We analyzed data for 1023 la/mUC patients diagnosed between January 2020 and December 2021 at 54 institutions from a Japanese nationwide cohort. RESULTS: At the median follow-up of 28.5 months, the median overall survival from first-line initiation for 905 patients who received systemic anticancer treatment was 19.1 months. Among them, 81% and 32% received second- and third-line treatment. Notably, 52% had their treatment terminated before the opportunity for third-line treatment. Multivariate logistic regression analysis revealed that low performance status (≥1), elevated neutrophil-to-lymphocyte ratio (≥3), and low body mass index (<21 kg/m2) at the start of first-line treatment were independent risk factors for not proceeding to third-line treatment (p = 0.0024, 0.0069, and 0.0058, respectively). In this cohort, 33% had one of these factors, 36% had two, and 15% had all three. CONCLUSIONS: This study highlights the high frequency of factors associated with poor tolerance to anticancer treatment in la/mUC patients. The findings suggest the need to establish optimal sequential treatment strategies, maximizing efficacy within time and tolerance constraints, while concurrently providing strong supportive care, considering immunological and nutritional aspects.

Drug extravasation with Enfortumab vedotin.

INTRODUCTION: Enfortumab vedotin is an antibody drug conjugate approved for management of pretreated locally advanced or metastatic urothelial carcinoma, which is associated with a rare risk of drug extravasation and soft tissue reactions. CASE REPORT: We report two cases of EV extravasation with subsequent development of bullae and cellulitis. MANAGEMENT AND OUTCOME: They were both treated for cellulitis and had conservative management without surgical intervention and were able to resume treatment with Enfortumab vedotin without subsequent adverse events. DISCUSSION: We propose that EV acts as a vesicant upon extravasation, highlight measures to prevent extravasation events, and encourage appropriate measures when dealing such as attempt of aspiration, removal of catheter, application of compresses, and thorough documentation with photographic evidence.

Physiologically based pharmacokinetic model to predict drug-drug interactions with the antibody-drug conjugate enfortumab vedotin.

Enfortumab vedotin is an antibody-drug conjugate (ADC) comprised of a Nectin-4-directed antibody and monomethyl auristatin E (MMAE), which is primarily eliminated through P-glycoprotein (P-gp)-mediated excretion and cytochrome P450 3A4 (CYP3A4)-mediated metabolism. A physiologically based pharmacokinetic (PBPK) model was developed to predict effects of combined P-gp with CYP3A4 inhibitor/inducer (ketoconazole/rifampin) on MMAE exposure when coadministered with enfortumab vedotin and study enfortumab vedotin with CYP3A4 (midazolam) and P-gp (digoxin) substrate exposure. A PBPK model was built for enfortumab vedotin and unconjugated MMAE using the PBPK simulator ADC module. A similar model was developed with brentuximab vedotin, an ADC with the same valine-citrulline-MMAE linker as enfortumab vedotin, for MMAE drug-drug interaction (DDI) verification using clinical data. The DDI simulation predicted a less-than-2-fold increase in MMAE exposure with enfortumab vedotin plus ketoconazole (MMAE geometric mean ratio [GMR] for maximum concentration [Cmax], 1.15; GMR for area under the time-concentration curve from time 0 to last quantifiable concentration [AUClast], 1.38). Decreased MMAE exposure above 50% but below 80% was observed with enfortumab vedotin plus rifampin (MMAE GMR Cmax, 0.72; GMR AUClast, 0.47). No effect of enfortumab vedotin on midazolam or digoxin systemic exposure was predicted. Results suggest that combination enfortumab vedotin, P-gp, and a CYP3A4 inhibitor may result in increased MMAE exposure and patients should be monitored for potential adverse effects. Combination P-gp and a CYP3A4 inducer may result in decreased MMAE exposure. No exposure change is expected for CYP3A4 or P-gp substrates when combined with enfortumab vedotin.ClinicalTrials.gov identifier Not applicable.

Enfortumab vedotin versus platinum rechallenge in post-platinum, post-pembrolizumab advanced urothelial carcinoma: A multicenter propensity score-matched study.

OBJECTIVE: Enfortumab vedotin (EV) was approved for advanced urothelial carcinoma (UC) in 2021 after the EV-301 trial showed its superiority to non-platinum-based chemotherapy as later-line treatment after platinum-based chemotherapy and immune checkpoint inhibitors including pembrolizumab. However, no study has compared EV with rechallenging platinum-based chemotherapy (i.e., "platinum rechallenge") in that setting. METHODS: In total, 283 patients received pembrolizumab for advanced UC after platinum-based chemotherapy between 2018 and 2023. Of them, 41 and 25 patients received EV and platinum rechallenge, respectively, as later-line treatment after pembrolizumab. After excluding two patients with EV without imaging evaluation, we compared oncological outcomes, including progression-free survival (PFS) and overall survival (OS), between the EV (n = 39) and platinum rechallenge groups (n = 25) using propensity score matching (PSM). RESULTS: Analyses on crude data (n = 64) showed no significant differences between the two groups regarding patients' baseline characteristics. PFS (5 months) and OS (11 months) in the EV group were comparable to those (8 and 12 months, respectively) in the platinum rechallenge group. After PSM (n = 36), the baseline characteristics between the two groups became more balanced, and PFS (not reached) and OS (not reached) in the EV group were comparable to those (8 and 11 months, respectively) in the platinum rechallenge group. CONCLUSIONS: EV and platinum rechallenge showed equivalent oncological outcomes, even after PSM, and both treatments should therefore be effective treatment options for post-platinum, post-pembrolizumab advanced UC.

Mechanisms of Resistance to Antibody-Drug Conjugates.

The treatment of cancer patients has dramatically changed over the past decades with the advent of monoclonal antibodies, immune-checkpoint inhibitors, bispecific antibodies, and innovative T-cell therapy. Antibody-drug conjugates (ADCs) have also revolutionized the treatment of cancer. Several ADCs have already been approved in hematology and clinical oncology, such as trastuzumab emtansine (T-DM1), trastuzumab deruxtecan (T-DXd), and sacituzumab govitecan (SG) for the treatment of metastatic breast cancer, and enfortumab vedotin (EV) for the treatment of urothelial carcinoma. The efficacy of ADCs is limited by the emergence of resistance due to different mechanisms, such as antigen-related resistance, failure of internalization, impaired lysosomal function, and other mechanisms. In this review, we summarize the clinical data that contributed to the approval of T-DM1, T-DXd, SG, and EV. We also discuss the different mechanisms of resistance to ADCs, as well as the ways to overcome this resistance, such as bispecific ADCs and the combination of ADCs with immune-checkpoint inhibitors or tyrosine-kinase inhibitors.

First experience in treating advanced urothelial cancer with enfortumab vedotin. Single-centre retrospective study of patients qualified for a rescue access procedure.

Introduction: Urothelial carcinoma is the most common type of urinary tract malignancy. Current treatment options, including platinum-based chemotherapy or immunotherapy, present significant challenges, ranging from limited efficacy to severe toxicities. Recent developments in antibody-drug conjugates (ADC), such as enfortumab vedotin (EV), promise to significantly improve overall survival. The study aims to evaluate the efficacy and tolerability of EV. In addition, we highlight the observed benefits of next-line treatment after progression. Material and methods: This retrospective study involved 16 patients with advanced urothelial cancer treated with EV at the Department of Genitourinary Oncology, Maria Sklodowska- Curie National Research Institute of Oncology between November 2022 and November 2023. The study evaluated patients' medical history, response to EV treatment, and side effects. Notably, the study included patients who had already exhausted standard treatment options and who were treated with EV through a rescue access procedure. Results: Partial response was observed in 4 out of 9 (44%) patients with available imaging. Common terminology criteria for adverse events (AE) grade 3 and 4 were observed in 3 out of 16 patients, which subsequently required dose reduction. Conclusions: Enfortumab vedotin demonstrates effectiveness in real-world settings in treating advanced urothelial cancer. Proper management of AE in experienced centres may further prolong survival. Personalized treatment and the development of new ADC represent the future for improved patient outcomes.