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.

Efficacy and safety of neoadjuvant PD-1 inhibitors or PD-L1 inhibitors for muscle invasive bladder cancer: a systematic review and meta-analysis

Introduction

This meta-analysis aims to evaluate the efficacy and safety of neoadjuvant PD-1 inhibitors or PD-L1 inhibitors [PD-(L)1 inhibitors] for muscle-invasive bladder carcinoma (MIBC).

Materials and methods

Four databases (Medline, Embase, Web of Science, and 21 CENTRAL) were searched for articles studying neoadjuvant PD-(L)1 inhibitors for MIBC. The search time period was from the establishment of each database to 21 July 2023. Meta-analyses of pCR, pPR, Grade≥ 3 irAEs rate, RFS, and OS were performed.

Results

In total, 22 studies were included for meta-analysis. The overall pooled pCR of neoadjuvant PD-(L)1 inhibitors was 0.36 (95%CI=0.30-0.42, p=0.00). In subgroup meta-analysis, the pooled PCR of PD-(L)1 inhibitors alone, PD-(L)1 inhibitors plus other ICI, and PD-(L)1 inhibitors plus chemotherapy was 0.27 (95%CI=0.19-0.35, p=0.1), 0.41 (95%CI=0.21-0.62, p=0.01), 0.43 (95%CI=0.35-0.50, p=0.06), respectively. The overall pooled pPR of neoadjuvant PD-(L)1 inhibitors was 0.53 (95%CI=0.46-0.60, p=0.00). In subgroup meta-analysis, the pooled pPR of PD-(L)1 inhibitors alone, PD-(L)1 inhibitors plus other ICI, and PD-(L)1 inhibitors plus chemotherapy was 0.36 (95%CI=0.22-0.51, p=0.01), 0.51 (95%CI=0.39-0.62, p=0.43), and 0.61 (95%CI=0.53-0.69, p=0.01), respectively. Kaplan-Meier curves for OS and RFS were reconstructed, but there was no significant difference among three groups in terms of OS or RFS. The pooled result of Grade≥ 3 irAEs rate for neoadjuvant PD-(L)1 inhibitors was 0.15 (95%CI=0.09-0.22, p=0.00%). In subgroup analysis, the pooled result of Grade≥ 3 irAEs rate for PD-(L)1 inhibitors alone, PD-(L)1 inhibitors plus other ICI, and PD-(L)1 inhibitors plus chemotherapy was 0.07 (95%CI=0.04-0.11, p=0.84), 0.31 (95%CI=0.16-0.47, p=0.06), and 0.17 (95%CI=0.06-0.31, I2 = 71.27%, p=0.01), respectively.

Conclusion

Neoadjuvant PD-(L)1 inhibitors were feasible and safe for muscle invasive bladder cancer. Compared with PD-(L)1 inhibitors alone, PD-(L)1 inhibitors plus other ICI and PD-(L)1 inhibitors plus chemotherapy were associated with higher pCR and pPR, but higher Grade≥3 irAEs. Kaplan-Meier curves for OS and RFS indicated that neoadjuvant PD-(L)1 inhibitors had an acceptable long-term prognostic, but it was not possible to discern statistical differences between the three neoadjuvant subgroups.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023452437, identifier PROSPERO (CRD42023452437).

The promise and challenges of combination therapies with antibody-drug conjugates in solid tumors

Antibody-drug conjugates (ADCs) represent an important class of cancer therapies that have revolutionized the treatment paradigm of solid tumors. To date, many ongoing studies of ADC combinations with a variety of anticancer drugs, encompassing chemotherapy, molecularly targeted agents, and immunotherapy, are being rigorously conducted in both preclinical studies and clinical trial settings. Nevertheless, combination therapy does not always guarantee a synergistic or additive effect and may entail overlapping toxicity risks. Therefore, understanding the current status and underlying mechanisms of ADC combination therapy is urgently required. This comprehensive review analyzes existing evidence concerning the additive or synergistic effect of ADCs with other classes of oncology medicines. Here, we discuss the biological mechanisms of different ADC combination therapy strategies, provide prominent examples, and assess their benefits and challenges. Finally, we discuss future opportunities for ADC combination therapy in clinical practice.

Immuno-Oncology Advances in Genitourinary Cancers

Immuno-oncology (IO) has made monumental gains in the past decade in the genitourinary space. In this review, we highlight advances with IO in renal cell carcinoma where it now has become standard-of-care frontline therapy in the metastatic setting but also discuss challenges with the initial approach. In urothelial carcinoma, we discuss the growing use of IO including exciting recent updates with IO-based regimens that may soon become the new standard of care. We further discuss difficulties with IO in prostate cancer, germ cell tumors, and penile squamous cell carcinoma. Finally, we highlight advances in IO approaches beyond checkpoint inhibition including the role of the gut microbiome and T-cell redirecting therapies.

[Antibody-drug conjugates as new therapeutic agents in uro-oncology]

Antibody-drug conjugates represent a new class of therapeutic agents that are already being used in the field of uro-oncology. They consist of an antibody directed against a specific tumour antigen linked to a cytotoxic substance ("payload") which acts after internalisation into the tumour cell and its release. Currently, approval in the European Union is restricted to enfortumab vedotin which is directed against nectin‑4 and carries the microtubule-inhibiting active ingredient monomethyl auristatin E (MMAE). Enfortumab vedotin is approved for locally advanced or metastatic urothelial carcinoma in the third line of therapy after platinum-based chemotherapy and after therapy with a programmed cell death (ligand) 1 (PD-[L]1) immune checkpoint inhibitor. However, an expansion of the indication of enfortumab vedotin as monotherapy and in combination with PD-(L)1 immune checkpoint inhibitors, as well as approval of other antibody-drug conjugates is expected in the future. This could sustainably change the therapy sequence in urothelial carcinoma. Currently, several clinical trials are recruiting in different therapeutic settings. This article presents the new substance class of antibody-drug conjugates, their mechanism of action, their representatives and clinical studies, and points out practice-relevant side effects and how to deal with them.

Antibody-Drug Conjugates in the Treatment of Urothelial Cancer

Antibody-drug conjugates (ADCs) have transformed the treatment landscape in oncology and become an essential therapeutic modality. In urothelial carcinoma (UC), the two ADCs that have been especially successful in clinical practice are enfortumab vedotin and sacituzumab govitecan. These drugs are currently approved as monotherapy for later lines of treatment in locally advanced or metastatic UC and have had a significant impact for patients with limited treatment options. Combinational trials, as well as additional ADCs, are currently being investigated in the treatment of UC for subsequent lines of therapy as overall survival rates remain dismal.

Somatic alterations of TP53 and MDM2 associated with response to enfortumab vedotin in patients with advanced urothelial cancer

Background

Enfortumab vedotin (EV) is an antibody-drug conjugate approved for patients with treatment-refractory advanced urothelial carcinoma (aUC), however data on biomarkers of response is lacking.

Methods

We retrospectively identified all aUC patients at our institution who received EV monotherapy and had next-generation sequencing (NGS) data available. Patients were considered responders if they had a complete response or partial response on restaging scans during treatment. Observed response rate (ORR) was evaluated by local investigator and compared between responders and non-responders using Chi-squared test. A univariable analysis was conducted using the Cox proportional hazard test to assess for associations between baseline characteristics and most common somatic alterations (in ≥10% of patients) with patient survival outcomes [progression-free survival (PFS) and overall survival (OS)]. Somatic alterations were then individually evaluated in separate multivariate models while accounting for patient and clinical characteristics using Cox regression models.

Results

Among 29 patients treated with EV monotherapy, 27 had available NGS data. Median age was 70, 24 (83%) were men, 19 (62%) were Caucasian, 15 (52%) had pure urothelial histology and 22 (76%) had primary tumor in the bladder. ORR was 41%, and PFS and OS for the overall cohort were 5.1 months and 10.2 months. Responders were enriched among patients with TP53, KDM6A and MDM2 alterations. Patients with these alterations, as well as those with composite TP53/MDM2 alterations (alterations in either TP53 or MDM2), also had increased ORR with EV treatment compared to patients without these alterations. In the univariable analysis, baseline albumin level ≥ 3.0g/dL and presence of composite TP53/MDM2 alterations were associated with a prolonged OS. Baseline ECOG 0/1, TP53 alterations and TP53/MDM2 alterations were associated with a prolonged PFS. In the multivariable analysis, TP53 and TP53/MDM2 alterations were genomic markers predictive of improved PFS after accounting for the relevant clinical characteristics.

Conclusion

In this single-center retrospective analysis of aUC patients treated with EV, presence of TP53 or MDM2 somatic alterations, lower ECOG PS scores (ECOG 0 or 1) and higher albumin levels (≥3 g/dL) were associated with improved outcomes with EV treatment. Prospective and external validation of these findings in larger cohorts is warranted.

Current Status of Perioperative Therapy in Muscle-Invasive Bladder Cancer and Future Directions

PURPOSE OF REVIEW

Cisplatin-based combination chemotherapy has been a standard of care in the perioperative management of muscle-invasive bladder cancer for years, but several novel therapies are under active investigation. This review aims to provide an update on recent relevant literature and a forward look at the future landscape of adjuvant and neoadjuvant therapy in muscle-invasive bladder cancer patients who opt for radical cystectomy.

RECENT FINDINGS

The recent approval of nivolumab as adjuvant therapy established a new treatment option for high-risk patients with muscle-invasive bladder cancer after radical cystectomy. Several phase II studies of chemo-immunotherapy combinations and immunotherapy alone have reported pathological complete responses in the 26-46% range, including studies in cisplatin-ineligible patients. Randomized studies of perioperative chemo-immunotherapy, immunotherapy alone, and enfortumab vedotin are ongoing. Muscle-invasive bladder cancer remains a challenging disease associated with significant morbidity and mortality; however, increasing options in systemic therapy and an increasingly personalized approach to cancer treatment suggest continued future improvements in patient care.

[Value of immunotherapy in the perioperative treatment of localized muscle invasive bladder cancer]

Immune checkpoint inhibitors are standard of care in the treatment of metastatic and locally advanced urothelial cancer. Their use in perioperative treatment is currently under investigation as monotherapy as well as in combination with chemotherapy or radiation regimens. This article provides an overview of recent trials, current data as well as an outlook on future developments in the perioperative management of urothelial cancer.

Enfortumab Vedotin Plus Pembrolizumab in Previously Untreated Advanced Urothelial Cancer

PURPOSE

Cisplatin-based combination chemotherapy remains the standard of care for locally advanced or metastatic urothelial cancer (la/mUC); however, toxicity is substantial, responses are rarely durable, and many patients with la/mUC are ineligible. Each enfortumab vedotin and pembrolizumab have shown a survival benefit versus chemotherapy in UC, are not restricted by cisplatin eligibility, and warrant investigation as a first-line (1L) combination therapy in patients ineligible for cisplatin.

METHODS

In this ongoing phase Ib/II, multicenter, open-label study, 1L cisplatin-ineligible patients with la/mUC received enfortumab vedotin 1.25 mg/kg once daily on days 1 and 8 and pembrolizumab 200 mg (day 1) intravenously once daily in 3-week cycles. The primary end point was safety. Key secondary end points included confirmed objective response rate, duration of response (DOR), and overall survival (OS).

RESULTS

Forty-five patients received enfortumab vedotin plus pembrolizumab. The most common treatment-related adverse events (TRAEs) were peripheral sensory neuropathy (55.6%), fatigue (51.1%), and alopecia (48.9%). Twenty-nine patients (64.4%) had grade 3 or higher TRAEs; the most common were increased lipase (17.8%), maculopapular rash (11.1%), and fatigue (11.1%). One death (2.2%) was classified as a TRAE. The confirmed objective response rate after a median of nine cycles was 73.3% with a complete response rate of 15.6%. The median DOR and median OS were 25.6 months and 26.1 months, respectively.

CONCLUSION

Enfortumab vedotin plus pembrolizumab showed a manageable safety profile. Most patients experienced tumor shrinkage. The median DOR and median OS exceeding 2 years in a cisplatin-ineligible patient population make this a promising combination currently under investigation in a phase III study (ClinicalTrials.gov identifier: NCT04223856).

Neoadjuvant Pembrolizumab and Radical Cystectomy in Patients with Muscle-Invasive Urothelial Bladder Cancer: 3-Year Median Follow-Up Update of PURE-01 Trial

PURPOSE

The PURE-01 study (NCT02736266) pioneered the neoadjuvant immune-checkpoint inhibitor (ICI) therapy before radical cystectomy (RC) in patients with muscle-invasive urothelial bladder carcinoma (MIBC). We herein present the survival outcomes after a median follow-up of three years.

PATIENTS AND METHODS

The intention-to-treat (ITT) population included 155 patients. Event-free survival (EFS) was defined as the time from pembrolizumab initiation until radiographic disease progression precluding RC, initiation of neoadjuvant chemotherapy, recurrence after RC, or death. Further outcomes were recurrence-free survival (RFS) post-RC and overall survival (OS). Multivariable Cox regression analyses for EFS were performed. Kaplan-Meier analyses compared EFS outcomes according with baseline programmed cell-death-ligand-1 (PD-L1) combined positive score (CPS) and according to the molecular subtypes.

RESULTS

After a median (interquartile range, IQR) follow-up of 39 (30-47) months, 36-month EFS and OS were 74.4% [95% confidence interval (CI), 67.8-81.7] and 83.8% (95% CI, 77.8-90.2) in the ITT population, respectively. Overall, 143 (92.3%) patients underwent RC. Within the cohort of patients who did not receive additional chemotherapy (N = 125), 36-month RFS was 96.3% (95% CI, 91.6-100) for patients achieving a ypT0N0, 96.1% (95% CI, 89-100) for ypT1/a/isN0, 74.9% (95% CI, 60.2-93) for ypT2-4N0, and 58.3% (95% CI, 36.2-94.1) for ypTanyN1-3 response. EFS was significantly stratified among PD-L1 tertiles (lower tertile: 59.7% vs. medium tertile: 76.7% vs. higher tertile: 89.8%, P = 0.0013). The claudin-low and basal/squamous subtypes displayed the lowest rates of events.

CONCLUSIONS

At a median follow-up of three years, PURE-01 results further confirm the sustained efficacy of neoadjuvant pembrolizumab before RC. PD-L1 expression was the strongest predictor of sustained response post-RC.

Advanced Bladder Cancer: Changing the Treatment Landscape

Bladder cancer is the 10th most common cancer type in the world. There were more than 573,000 new cases of bladder cancer in 2020. It is the 13th most common cause of cancer death with an estimated more than 212,000 deaths worldwide. Low-grade non-muscle-invasive bladder cancer (NMIBC) is usually successfully managed with transurethral resection (TUR) and overall survival for NMIBC reaches 90% according to some reports. However, long-term survival for muscle-invasive bladder cancer (MIBC) and metastatic bladder cancer remains low. Treatment options for bladder cancer have undergone a rapid change in recent years. Immune checkpoint inhibitors (ICI), targeted therapies, and antibody-drug conjugates are available now. As bladder cancer is genetically heterogeneous, the optimization of patient selection to identify those most likely to benefit from a specific therapy is an urgent issue in the treatment of patients with bladder cancer.

Disparities in access to novel systemic therapies in patients with urinary tract cancer: Propagating access, policies and resources uniformly

After several decades of therapeutic stagnation, the treatment of patients with urothelial carcinoma has met a revolutionary wave, anticipated by the advent of immune-checkpoint inhibitors (ICI) and followed by newer therapeutic options in the post-ICI setting. These achievements were made in a very short time-frame, thus making the treatment of this disease particularly susceptible to geographical health disparity due to the differences in healthcare systems and approval processes of the regulatory authorities. Furthermore, additional barriers to access innovative care are represented by a limited coverage of clinical trials availability, that is consistent in focusing on selected geographical areas, across trials and clinical settings. Here, we present the current picture of new drug approvals in urothelial carcinoma worldwide, and we also focus our considerations onto the spectrum of ongoing trial inclusion possibilities, trying to understand what are the current gaps in clinical research and routine practice, identifying a way to move forward.

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

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

Evolving Role of Adjuvant Systemic Therapy for Kidney and Urothelial Cancers

The role of adjuvant therapy in renal cell carcinoma and urothelial carcinoma is rapidly evolving. To date, the U.S. Food and Drug Administration has approved sunitinib and pembrolizumab in the adjuvant setting for renal cell carcinoma and nivolumab for urothelial carcinoma based on disease-free survival benefit. The U.S. Food and Drug Administration held a joint workshop with the National Cancer Institute and the Society of Urologic Oncology in 2017 to harmonize design elements, including eligibility and radiologic assessments across adjuvant trials in renal cell carcinoma and urothelial carcinoma. Considerations from the discussion at these workshops led the U.S. Food and Drug Administration to draft guidances to help inform subsequent adjuvant trial design for renal cell carcinoma and urothelial carcinoma. Patient-centered decision-making is crucial when determining therapeutic choices in the adjuvant setting; utility functions can be used to help quantify each patient's goals, values, and risk/benefit trade-offs to ensure that the decision regarding adjuvant therapy is informed by their preferences and the evolving outcomes data.

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

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

Adjuvant immunotherapy for muscle-invasive urothelial carcinoma of the bladder

INTRODUCTION

There are substantial unmet needs with regards to adjuvant therapy for muscle-invasive urothelial carcinoma (UC) of the bladder, including patients with persistent disease histologically following neoadjuvant platinum-based therapy and radical resection, as well as patients who are not eligible for or refuse cytotoxic chemotherapy. As such, increased interest has been developed in advancing the use of systemic immunotherapy in the postoperative setting.

AREAS COVERED

We begin by examining current uses of systemic immunotherapy in the treatment of advanced UC. We also review emerging neoadjuvant data and describe current adjuvant approaches. We then report and analyze data on adjuvant immunotherapy, including the recent randomized trials on adjuvant nivolumab and atezolizumab, and conclude with a discussion on the available evidence and likely directions of the field.

EXPERT OPINION

Systemic immunotherapy can serve to enhance postoperative therapies for muscle-invasive bladder UC, as exemplified by the recent approval of nivolumab. Further research will serve to define optimal immunotherapy timing and combinations with other systemic therapies, as well as identify predictive biomarkers to allow effective tailoring of therapy for each patient.