Phase II trial of intravesical nanoparticle albumin bound paclitaxel for the treatment of nonmuscle invasive urothelial carcinoma of the bladder after bacillus Calmette-Guérin treatment failure

Potential bladder cancer therapeutic delivery systems: a recent update

INTRODUCTION

Bladder Cancer is one of the most expensive cancers to treat due to its high cost of therapy as well as the surveillance expenses incurred to prevent disease recurrence and progression. Thus, there is a strong need to develop safe, efficacious drug formulations with controlled drug release profiles and tumor-targeting potential, for improved therapeutic outcomes of bladder cancer patients.

AREAS COVERED

This review aims to provide an overview of drug formulations that have been studied for potential bladder cancer treatment in the last decade; highlight recent trends in bladder cancer treatment; mention ongoing clinical trials on bladder cancer chemotherapy; detail recently FDA-approved drug products for bladder cancer treatment and identify constraints that have prevented the translation of promising drug formulations from the research laboratory to the clinics.

EXPERT OPINION

This work revealed that surface functionalization of particulate drug delivery systems and incorporating the nanoparticles into in situ gelling systems could facilitate controlled drug release for extended periods, and improve the prognosis of bladder cancer treatment. Future research directions could incorporate multiple drugs into the drug delivery systems to treat advanced stages of the disease. In addition, smart nanomaterials, including photothermal therapies, could be exploited to improve the therapeutic outcomes of bladder cancer patients.

A systematic review of nanocarriers for treatment of urologic cancers

Nanocarriers (NCs) are a form of nanotechnology widely investigated in cancer treatment to improve the safety and efficacy of systemic therapies by increasing tumor specificity. Numerous clinical trials have explored the use of NCs in urologic cancers since the approval of the first NCs for cancer treatment over 20 years ago. The objective of this systematic review is to examine the effectiveness and safety of NCs in treating urological cancers. This paper summarizes the state of the field by investigating peer-reviewed, published results from 43 clinical trials involving the use of NCs in bladder, prostate, and kidney cancer patients with a focus on safety and efficacy data. Among the 43 trials, 16 were phase I, 20 phase II, and 4 phase I/II. No phase III trials have been reported. While both novel and classic NCs have been explored in urologic cancers, NCs already approved for the treatment of other cancers were more widely represented. Trials in prostate cancer and mixed trials involving both urologic and non-urologic cancer patients were the most commonly reported trials. Although NCs have demonstrable efficacy with adequate safety in non-urologic cancer patient populations, current clinical stage NC options appear to be less beneficial in the urologic cancer setting. For example, nab-paclitaxel and liposomal doxorubicin have proven ineffective in the treatment of urologic cancers despite successes in other cancers. However, several ongoing pre-clinical studies using targeted and locally applied improved NCs may eventually improve their utility.

Local Drug Delivery in Bladder Cancer: Advances of Nano/Micro/Macro-Scale Drug Delivery Systems

Treatment of bladder cancer remains a critical unmet need and requires advanced approaches, particularly the development of local drug delivery systems. The physiology of the urinary bladder causes the main difficulties in the local treatment of bladder cancer: regular voiding prevents the maintenance of optimal concentration of the instilled drugs, while poor permeability of the urothelium limits the penetration of the drugs into the bladder wall. Therefore, great research efforts have been spent to overcome these hurdles, thereby improving the efficacy of available therapies. The explosive development of nanotechnology, polymer science, and related fields has contributed to the emergence of a number of nanostructured vehicles (nano- and micro-scale) applicable for intravesical drug delivery. Moreover, the engineering approach has facilitated the design of several macro-sized depot systems (centimeter scale) capable of remaining in the bladder for weeks and months. In this article, the main rationales and strategies for improved intravesical delivery are reviewed. Here, we focused on analysis of colloidal nano- and micro-sized drug carriers and indwelling macro-scale devices, which were evaluated for applicability in local therapy for bladder cancer in vivo.

Sequential intravesical gemcitabine/docetaxel provides a durable remission in recurrent high-risk NMIBC following BCG therapy

PURPOSE

Bacillus Calmette-Guerin (BCG) is the standard of care for high-risk nonmuscle invasive bladder cancer (NMIBC), but half of patients develop disease recurrence. Intravesical regimens for BCG unresponsive NMIBC are limited. We report the safety, efficacy, and differential response of sequential gemcitabine/docetaxel (gem/doce) depending on BCG failure classification.

METHODS

Multi-institutional retrospective analysis of patients treated with induction intravesical gem/doce (≥5/6 instillations) for recurrent high-risk NMIBC after BCG therapy from May 2018 to December 2021. Maintenance therapy was provided to those without high-grade (HG) recurrence on surveillance cystoscopy. Kaplan-Meier curves and Cox regression analyses were utilized to assess survival and risk factors for disease recurrence.

RESULTS

Our cohort included 102 patients with BCG-unresponsive NMIBC. Median age was 72 years and median follow-up was 18 months. Six-, 12-, and 24-month high-grade recurrence-free survival was 78%, 65%, and 49%, respectively. Twenty patients underwent radical cystectomy (median 15.5 months from induction). Six patients progressed to muscle invasive disease. Fifty-seven percent of patients experienced mild/moderate adverse effects (AE), but only 6.9% experienced a delay in treatment schedule. Most common AE were urinary frequency/urgency (41%) and dysuria (21%). Patients with BCG refractory disease were more likely to develop HG recurrence when compared to patients with BCG relapsing disease (HR 2.14; 95% CI 1.02-4.49).

CONCLUSIONS

In patients with recurrence after BCG therapy, sequential intravesical gem/doce is an effective and well-tolerated alternative to early cystectomy. Patients with BCG relapsing disease are more likely to respond to additional intravesical gem/doce. Further investigation with a prospective trial is imperative.

New Intravesical Agents for BCG-Unresponsive High-Risk Non-Muscle Invasive Bladder Cancer

BACKGROUND

With the exception of the FDA-approved valrubicin and pembrolizumab, there are no standard second-line treaments for BCG-unresponsive high-risk non-muscle invasive bladder cancer (NMIBC).

OBJECTIVES

To provide a systematic review of the novel intravesically administered therapeutic agents for the salvage treatment of BCG-unresponsive NMIBC.

METHODS

Online search of the PubMed, EMBASE and Web of Science databases was performed. The endpoints of this review were to evaluate the efficacy of the agents in terms of complete response rates (CR) and durability of CR, overall survival, recurrence-free survival and cancer-specific survival and to report on their toxicity profile. A search on Clinicaltrials.gov was performed to identify ongoing clinical trials.

RESULTS

14 studies were included in this review. The critical clinical need for the development of an effective, safe and durable intravesical drug for the salvage treatment of high-risk NMIBC seems to be met mainly by intravesical gene therapy; in fact, data support the FDA-approved nadofaragene firadenovec as a potentially important therapeutic advancement in this context. Promising results are also being obtained by the combination of N-803/BCG and by innovative drug delivery systems.

CONCLUSIONS

Considering the plethora of novel intravesical treatments that have completed phase II evaluation, one can reasonably expect that clinicians will soon have at their disposal new agents and treatment options for BCG-unresponsive NMIBC. In the near future, it will be up to the urologist to identify, for each specific patient, the right agent to use, based on safety, results and cost-effectiveness.

Nanoprobe-based molecular imaging for tumor stratification

The responses of patients to tumor therapies vary due to tumor heterogeneity. Tumor stratification has been attracting increasing attention for accurately distinguishing between responders to treatment and non-responders. Nanoprobes with unique physical and chemical properties have great potential for patient stratification. This review begins by describing the features and design principles of nanoprobes that can visualize specific cell types and biomarkers and release inflammatory factors during or before tumor treatment. Then, we focus on the recent advancements in using nanoprobes to stratify various therapeutic modalities, including chemotherapy, radiotherapy (RT), photothermal therapy (PTT), photodynamic therapy (PDT), chemodynamic therapy (CDT), ferroptosis, and immunotherapy. The main challenges and perspectives of nanoprobes in cancer stratification are also discussed to facilitate probe development and clinical applications.

BCG-Unresponsive Non-Muscle-Invasive Bladder Cancer: Current Treatment Landscape and Novel Emerging Molecular Targets

Urothelial carcinoma (UC), the sixth most common cancer in Western countries, includes upper tract urothelial carcinoma (UTUC) and bladder carcinoma (BC) as the most common cancers among UCs (90-95%). BC is the most common cancer and can be a highly heterogeneous disease, including both non-muscle-invasive (NMIBC) and muscle-invasive (MIBC) forms with different oncologic outcomes. Approximately 80% of new BC diagnoses are classified as NMIBC after the initial transurethral resection of the bladder tumor (TURBt). In this setting, intravesical instillation of Bacillus Calmette-Guerin (BCG) is the current standard treatment for intermediate- and high-risk patients. Unfortunately, recurrence occurs in 30% to 40% of patients despite adequate BCG treatment. Radical cystectomy (RC) is currently considered the standard treatment for NMIBC that does not respond to BCG. However, RC is a complex surgical procedure with a recognized high perioperative morbidity that is dependent on the patient, disease behaviors, and surgical factors and is associated with a significant impact on quality of life. Therefore, there is an unmet clinical need for alternative bladder-preserving treatments for patients who desire a bladder-sparing approach or are too frail for major surgery. In this review, we aim to present the strategies in BCG-unresponsive NMIBC, focusing on novel molecular therapeutic targets.

Novel Delivery Mechanisms for Existing Systemic Agents and Emerging Therapies in Bladder Cancer

Systemic agents including immune checkpoint inhibitors, antibody-drug conjugates, and targeted therapies play a critical role in the management of bladder cancer. Novel localized delivery mechanisms for existing systemic agents explore solutions to improve treatment response without compromising safety. Herein, we review the contemporary innovations in modern intravesical agents, hyperthermic drug delivery, reverse-thermal gels, nanocarriers, gene therapy, and subcutaneous therapies.

Novel intravesical therapeutics in the treatment of non-muscle invasive bladder cancer: Horizon scanning

Introduction

Non-muscle-invasive bladder cancer (NMIBC) is a common and heterogeneous disease; many patients develop recurrent or progress to muscle-invasive disease. Intravesical drug therapy is a pillar in the current management of NMIBC; notwithstanding, Mitomycin C (MMC) and Bacillus Calmette-Guérin (BCG) have numerous limitations including international supply issues, and local and systemic toxicity. Here we review novel intravesical therapeutic options and drug delivery devices with potential for clinical use in the treatment of NMIBC.

Methods

PubMed, ClinicalTrials.gov and Cochrane Library searches were undertaken. Systematic reviews, meta-analyses, randomised controlled trials, single-arm clinical trials and national/international conference proceedings were included.

Results

Novel intravesical drugs, including chemotherapeutic agents, immune checkpoint inhibitors, monoclonal antibodies and gene therapies, have demonstrated varying efficacy in the treatment of NMIBC. Current evidence for the majority of treatments is mostly limited to single-arm trials in patients with recurrent NMIBC. Various novel methods of drug delivery have also been investigated, with encouraging preliminary results supporting the intravesical delivery of hyperthermic MMC and MMC hydrogel formulations.

Conclusions

Novel therapeutic agents and drug delivery systems will be important in the future intravesical management of NMIBC. As our understanding of the molecular diversity of NMIBC develops, molecular subtyping will become fundamental in the personalisation of intravesical treatments. Further randomised studies are urgently required to investigate the efficacy of novel intravesical treatments and novel regimens, in comparison to current standards-of-care, particularly in the context of international BCG shortages.

Nanomedicine for urologic cancers: diagnosis and management

Urologic cancers accounted for more than 2 million new cases and around 0.8 million deaths in 2020. Although surgery, chemotherapy, and radiotherapy, as well as castration for prostate cancer, remain the cornerstones for managing urologic neoplasms, they can result in severe adverse effects, poor patient compliance, and unsatisfactory survival rates, thus, it is essential to develop novel options that enable the early detection of these malignancies, together with providing accurate diagnoses, and more efficient treatment strategies. Nanomedicine represents an emerging approach that can deliver formulations or drugs across traditional biological barriers in the body and be directed to specific cell types within target organs via active targeting or passive targeting, thus, showing potential to improve the management of urologic cancers. In this review, we discussed the most recent updates on the application of nanomedicines in the diagnosis and treatment of urologic cancers, with focus on prostate, bladder and kidney tumors. We also presented the anti-tumor molecular mechanisms of newly designed nanomedicine for treating urologic cancers, mainly including image-guided surgery, chemotherapy, radiotherapy, gene therapy, immunotherapy, and their synergetic therapy. Current studies have demonstrated the potential advantages of nanomedicine over conventional approaches. However, most developments and new findings in this area have not been validated in clinical trials yet, and therefore, efforts shall be made to translate these research insights into clinical practices for urologic cancers.

New Perspectives in the Medical Treatment of Non-Muscle-Invasive Bladder Cancer: Immune Checkpoint Inhibitors and Beyond

Non-muscle-invasive bladder cancer (NMIBC) is characterized by a high rate of cure, but also by a non-negligible probability of recurrence and risk progression to muscle-invasive disease. NMIBC management requires a proper local resection and staging, followed by a risk-based treatment with intravesical agents. For many years, the current gold standard treatment for patients with intermediate or high-risk disease is transurethral resection of the bladder (TURB) followed by intravesical bacillus Calmette-Guérin (BCG) instillations. Unfortunately, in about half of high-risk patients, intravesical BCG treatment fails and NMIBC persists or recurs early. While radical cystectomy remains the gold standard for these patients, new therapeutic targets are being individuated and studied. Radical cystectomy in fact can provide an excellent long-term disease control, but can deeply interfere with quality of life. In particular, the enhanced immune checkpoints expression shown in BCG-unresponsive patients and the activity of immune checkpoints inhibitors (ICIs) in advanced bladder cancer provided the rationale for testing ICIs in NMIBC. Recently, pembrolizumab has shown promising activity in BCG-unresponsive NMIBC patients, obtaining FDA approval. Meanwhile multiple novel drugs with alternative mechanisms of action have proven to be safe and effective in NMIBC treatment and others are under investigation. The aim of this review is to analyse and describe the clinical activity of new emerging drugs in BCG-unresponsive NMIBC focusing on immunotherapy results.

Application of nanotechnology in the diagnosis and treatment of bladder cancer

Bladder cancer (BC) is a common malignancy in the genitourinary system and the current theranostic approaches are unsatisfactory. Sensitivity and specificity of current diagnosis methods are not ideal and high recurrence and progression rates after initial treatment indicate the urgent need for management improvements in clinic. Nanotechnology has been proposed as an effective method to improve theranosis efficiency for both non-muscle invasive bladder cancer (NMIBC) and muscle invasive bladder cancer (MIBC). For example, gold nanoparticles (AuNPs) have been developed for simple, fast and sensitive urinary sample test for bladder cancer diagnosis. Nanoparticles targeting bladder cancers can facilitate to distinguish the normal and abnormal bladder tissues during cystoscopy and thus help with the complete removal of malignant lesions. Both intravenous and intravesical agents can be modified by nanotechnology for targeted delivery, high anti-tumor efficiency and excellent tolerability, exhibiting encouraging potential in bladder cancer treatment. Photosensitizers and biological agents can also be delivered by nanotechnology, intermediating phototherapy and targeted therapy. The management of bladder cancer remained almost unchanged for decades with unsatisfactory effect. However, it is likely to change with the fast-developed nanotechnology. Herein we summarized the current utility of nanotechnology in bladder cancer diagnosis and treatment, providing insights for the future designing and discovering novel nanoparticles for bladder cancer management.

Emerging treatments for bacillus Calmette-Guérin-unresponsive non-muscle-invasive bladder cancer

Intravesical bacillus Calmette–Guérin (BCG) immunotherapy has been the gold standard adjuvant treatment for intermediate- and high-risk non-muscle-invasive bladder cancer (NMIBC) after transurethral resection of bladder tumor (TURBT). BCG immunotherapy prevents disease recurrence and progression to muscle-invasive disease following TURBT. Although most patients initially respond well to intravesical BCG, considerable concern has been raised for patients with BCG failure who are refractory or recur in 6 months after their last BCG, which implies ‘BCG-unresponsiveness’. Based on current clinical guidelines, early radical cystectomy (RC) is recommended to treat BCG-unresponsive NMIBC. However, due to the high risk of morbidity and mortality of RC and patients' desire to preserve their own bladder, there is a critical unmet need for alternative conservative treatments as bladder-sparing strategies in BCG-unresponsive patients. Trials for effective bladder-sparing treatments are ongoing, and several novel agents have been recently tested in the NMIBC setting. The goal of this review is to introduce and summarize recently reported novel and emerging drugs and ongoing clinical trials for BCG-unresponsive NMIBC.

The current landscape of salvage therapies for patients with bacillus Calmette-Guérin unresponsive nonmuscle invasive bladder cancer

PURPOSE OF REVIEW

Although radical cystectomy represents the gold standard treatment for patients with high-risk nonmuscle invasive bladder cancer (NMIBC) whose disease does not respond to bacillus Calmette-Guérin (BCG), many patients are unable or unwilling to undergo surgery. The need remains for effective bladder-preserving therapies. This review aims to describe existing treatments, contemporary research in this field and ongoing trials of salvage therapies for patients with BCG-unresponsive NMIBC.

RECENT FINDINGS

Intravesical chemotherapy has been utilized frequently in this setting. Emerging data on combination regimens such as intravesical gemcitabine and docetaxel and intravesical cabazitaxel, gemcitabine and cisplatin are promising; nevertheless, larger, prospective trials are needed. Meanwhile, the intravenous checkpoint inhibitor pembrolizumab was recently FDA-approved for patients BCG-unresponsive NMIBC. Encouraging clinical trial results for intravesical nadofaragene firadenovec, oportuzumab monatox and ALT-803 + BCG have been released, while data from trials of other treatment strategies, including novel chemotherapy and drug delivery, augmented BCG immunotherapy, adenoviral and gene therapy, targeted therapy, and combination systemic immunotherapy with intravesical agents, are eagerly awaited.

SUMMARY

Several novel salvage therapies offer promise for patients with BCG-unresponsive NMIBC. Patient selection, efficacy, safety, cost and ease of administration must be carefully considered to determine the optimal treatment approach.

Advances in bladder cancer biology and therapy

The field of research in bladder cancer has seen significant advances in recent years. Next-generation sequencing has identified the genes most mutated in bladder cancer. This wealth of information allowed the definition of driver mutations, and identification of actionable therapeutic targets, as well as a clearer picture of patient prognosis and therapeutic direction. In a similar vein, our understanding of the cellular aspects of bladder cancer has grown. The identification of the cellular geography and the populations of different cell types and quantifications of normal and abnormal cell types in tumours provide a better prediction of therapeutic response. Non-invasive methods of diagnosis, including liquid biopsies, have seen major advances as well. These methods will likely find considerable utility in assessing minimal residual disease following treatment and for early-stage diagnosis. A significant therapeutic impact on patients with bladder cancer is found in the use of immune checkpoint inhibitor therapeutics. These therapeutics have been shown to cure some patients with bladder cancer and significantly decrease adverse events. These developments provide patients with better monitoring opportunities, unique therapeutic options and greater hope for prolonged survival.

Intravesical nadofaragene firadenovec gene therapy for BCG-unresponsive non-muscle-invasive bladder cancer: a single-arm, open-label, repeat-dose clinical trial

BACKGROUND

BCG is the most effective therapy for high-risk non-muscle-invasive bladder cancer. Nadofaragene firadenovec (also known as rAd-IFNa/Syn3) is a replication-deficient recombinant adenovirus that delivers human interferon alfa-2b cDNA into the bladder epithelium, and a novel intravesical therapy for BCG-unresponsive non-muscle-invasive bladder cancer. We aimed to evaluate its efficacy in patients with BCG-unresponsive non-muscle-invasive bladder cancer.

METHODS

In this phase 3, multicentre, open-label, repeat-dose study done in 33 centres (hospitals and clinics) in the USA, we recruited patients aged 18 years or older, with BCG-unresponsive non-muscle-invasive bladder cancer and an Eastern Cooperative Oncology Group status of 2 or less. Patients were excluded if they had upper urinary tract disease, urothelial carcinoma within the prostatic urethra, lymphovascular invasion, micropapillary disease, or hydronephrosis. Eligible patients received a single intravesical 75 mL dose of nadofaragene firadenovec (3 × 1011 viral particles per mL). Repeat dosing at months 3, 6, and 9 was done in the absence of high-grade recurrence. The primary endpoint was complete response at any time in patients with carcinoma in situ (with or without a high-grade Ta or T1 tumour). The null hypothesis specified a complete response rate of less than 27% in this cohort. Efficacy analyses were done on the per-protocol population, to include only patients strictly meeting the BCG-unresponsive definition. Safety analyses were done in all patients who received at least one dose of treatment. The study is ongoing, with a planned 4-year treatment and monitoring phase. This study is registered with ClinicalTrials.gov, NCT02773849.

FINDINGS

Between Sept 19, 2016, and May 24, 2019, 198 patients were assessed for eligibility. 41 patients were excluded, and 157 were enrolled and received at least one dose of the study drug. Six patients did not meet the definition of BCG-unresponsive non-muscle-invasive bladder cancer and were therefore excluded from efficacy analyses; the remaining 151 patients were included in the per-protocol efficacy analyses. 55 (53·4%) of 103 patients with carcinoma in situ (with or without a high-grade Ta or T1 tumour) had a complete response within 3 months of the first dose and this response was maintained in 25 (45·5%) of 55 patients at 12 months. Micturition urgency was the most common grade 3-4 study drug-related adverse event (two [1%] of 157 patients, both grade 3), and there were no treatment-related deaths.

INTERPRETATION

Intravesical nadofaragene firadenovec was efficacious, with a favourable benefit:risk ratio, in patients with BCG-unresponsive non-muscle-invasive bladder cancer. This represents a novel treatment option in a therapeutically challenging disease state.

FUNDING

FKD Therapies Oy.

Side Effects of Intravesical BCG and Chemotherapy for Bladder Cancer: What They Are and How to Manage Them

Intravesical therapy for nonmuscle invasive bladder cancer decreases recurrence and progression but carries a high risk of side effects, which limit patient adherence. Appropriate management of the toxicities from intravesical therapy requires consideration of the agent used, the side effects experienced, and the timing of those side effects. Management strategies for intravesical toxicities ideally improve patient tolerance without sacrificing oncologic outcomes. This review aims to provide a comprehensive overview of the available evidence regarding the side effects of intravesical therapies for nonmuscle invasive bladder cancer and to propose practical strategies for toxicity management.

Novel anticancer therapy in BCG unresponsive non-muscle-invasive bladder cancer

INTRODUCTION

Many patients with non-muscle-invasive bladder cancer (NMIBC) failed intravesical BCG therapy. Currently, radical cystectomy is the recommended standard of care for those patients. There is unfortunately no effective other second-line therapy recommended.

AREAS COVERED

In this review, we present the topics of BCG unresponsive NMIBC; definition, prognosis, and further treatment options: immunotherapy, intravesical chemotherapy, gene therapy, and targeted individualized therapy.

EXPERT OPINION

There are major challenges of the management of NMIBC who failed BCG therapy as many patients refuse or are unfit for radical cystectomy. Multiple new modalities currently under investigation in ongoing clinical trials to better treat this category of patients. Immunotherapy, especially PD-1/PD-L1 inhibitors, offers exciting and potentially effective strategies for the treatment of BCG unresponsive NMIBC. As the data expands, it is sure that soon there will be established new guidelines for NMIBC.

Sequential administration of Bacillus Calmette-Guerin (BCG) and Electromotive Drug Administration (EMDA) of mitomycin C (MMC) for the treatment of high-grade nonmuscle invasive bladder cancer after BCG failure

BACKGROUND

There is a need for effective nonsurgical treatment options in patients with nonmuscle invasive bladder cancer (NMIBC) in whom Bacillus Calmette-Guerin (BCG) therapy has failed.

OBJECTIVE

We aimed to determine the efficacy of Electromotive Drug Administration (EMDA) of mitomycin C (MMC) with NMIBC after BCG failure.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective review of 26 NMIBC patients in whom BCG therapy failed who received BCG/EMDA-MMC between 2013 and 2017 was performed. All but 4 patients fulfilled the FDA criteria for BCG unresponsive disease. Progression and recurrence-free survival (RFS)were calculated using Kaplan-Meier curves. Progression was defined as development of muscle invasive disease, presence of metastasis on imaging or treatment. We used FDA-defined criteria as complete response (CR) for single-arm trials of BCG-unresponsive patients.

RESULTS AND LIMITATIONS

Twenty-six patients were included. Initial pathology was carcinoma in situ (CIS) in 53.8% (14/26), pT1 in 34.6% (9/26), and pTa HG disease in 11.6% (3/26). Twelve of 26 patients progressed (46.2%). Following BCG/EMDA-MMC treatment, progression-free survival rates were 58.3% (95% confidence interval [CI] 41.1-82.1) at 1 year and 48.9% (95% CI 48.9) at 2 years from the date of induction of BCG/EMDA-MMC, respectively. RFS was 41.9% (95% CI 25.9-67.8) at 1 year and 27.2% (95% CI 13.6-54.4) at 2 years. CR at 6, 12, and 18 months was observed in 16 (61.5%), 11 (44.0%), and 7 patients (30.4%), respectively. Side effects included dysuria (19.2%), hematuria (19.2%), and frequency (11.5%). Three patients were admitted for side effects but managed conservatively. Four patients (15.4%) died of bladder cancer over the course of the study.

CONCLUSIONS

EMDA-MMC BCG represents a viable option in patients with BCG unresponsive NMIBC with close to 50% progression-free survival at 2 years. However, these patients have a high risk of death from bladder cancer (15% in our cohort at 2 years) thus warranting extremely close surveillance.

Salvage therapeutic strategies for bacillus Calmette-Guerin failure

PURPOSE OF REVIEW

To give an overview of current options for conservative treatment of patients failing intravesical bacillus Calmette-Guerin (BCG) and to discuss emerging approaches with potential future clinical applications.

RECENT FINDINGS

Radical cystectomy is the standard-of-care for patients failing BCG therapy. In patients unfit or unwilling to undergo surgery, salvage therapy options could be proposed with the aim to offer local cancer control and prevent progression to muscle-invasive disease. Salvage treatments have been conducted using intravesical chemotherapy regimens, chemoradiation or chemohyperthermia. Intravesical agents such as valrubicin, gemcitabine or docetaxel showed response rates varying between 16 and 40%, whereas combination treatments of gemcitabine with docetaxel or mitomycin reported response rates in up to 50% of all patients with durable responses in about one out of three patients. For chemohyperthermia, 2-year recurrence rates between 41 and 56% have been reported. Ongoing clinical trials are evaluating chemoradiation as well as novel approaches such as systemic immunotherapy, viral gene therapy, targeted therapy or vaccination strategies with promising preliminary outcomes.

SUMMARY

Salvage therapeutic bladder-sparing strategies for BCG failure such as intravesical chemotherapy or chemoradiation should currently only be considered in patients unfit for or refusing surgery. Innovative concepts such as chemohyperthermia, checkpoint inhibitors, targeted therapy or viral gene therapy could lead to major changes in clinical management of BCG failures in the future.

Systematic Review of the Therapeutic Efficacy of Bladder-preserving Treatments for Non-muscle-invasive Bladder Cancer Following Intravesical Bacillus Calmette-Guérin

CONTEXT

There is a critical need for effective bladder-sparing therapies for bacillus Calmette-Guérin (BCG)-unresponsive non-muscle-invasive bladder cancer (NMIBC). Owing to the current lack of effective agents that can be used as a control, the US Food and Drug Administration began to accept single-arm trials for patients with carcinoma in situ (CIS), using complete response rate (CRR) and duration of response as the primary endpoints to support marketing applications. Despite the ensuing growth of clinical trials in this space, no consensus exists on a clinically relevant benchmark for CRR.

OBJECTIVE

To elucidate the CRR and recurrence-free rate (RFR) using bladder-sparing agents after BCG failure in order to provide a frame of reference for future clinical trial results.

EVIDENCE ACQUISITION

We performed a systematic review of clinical trials utilizing bladder-sparing therapeutics for NMIBC recurring after intravesical BCG (PROSPERO CRD42019130553). The search was performed in MEDLINE, EMBASE, and Cochrane Library. Relevant studies identified from bibliography search and conference abstracts were searched to complement the systematic review. A total of 42 studies utilizing 24 treatment options and consisting of 2254 patients were included for final analysis.

EVIDENCE SYNTHESIS

Median CRRs in the treatment of CIS-containing tumors were 26% at 6 mo, 17% at 12 mo, and 8% at 24 mo after treatment. In comparison, median RFRs in the papillary-only studies were 67% at 6 mo, 44% at 12 mo, and 10% at 24 mo. Specifically in the BCG-unresponsive population, 6- and 12-mo CRRs in CIS-containing patients treated with Mycobacterium phlei cell wall-nucleic acid complex were 45% and 27%, respectively, and the median 6-, 12-, and 24-mo disease-free rates in the other studies were 43%, 35%, and 18%, respectively. The median progression-free rate was 91%: 95% in the CIS-containing studies and 89% in studies restricted to papillary-only recurrences. Toxicities of intravesical agents were generally mild, with very few dose limiting toxicities.

CONCLUSIONS

We demonstrate that, to date, bladder-sparing therapies achieved modest efficacy in patients with NMIBC after BCG. Results from the current study will serve as a frame of reference for emerging trial results in the BCG-unresponsive space.

PATIENT SUMMARY

In this study, we found that bladder-sparing therapies achieved modest efficacy in patients with non-muscle-invasive bladder cancer after bacillus Calmette-Guérin (BCG). These results will serve to inform future clinical trial results for salvage agents used to treat BCG-unresponsive bladder cancer.

Optimizing pharmacokinetics of intravesical chemotherapy for bladder cancer

Non-muscle-invasive bladder cancer (NMIBC) remains one of the most common malignancies and is associated with considerable treatment costs. Patients with intermediate-risk or high-risk disease can be treated with intravesical BCG, but many of these patients will experience tumour recurrence, despite adequate treatment. Standard of care in these patients is radical cystectomy with urinary diversion, but this approach is associated with considerable morbidity and lifestyle modification. As an alternative, perioperative intravesical chemotherapy is recommended for low-risk papillary NMIBC, and induction intravesical chemotherapy is an option for patients with intermediate-risk NMIBC and BCG-unresponsive NMIBC. However, poor pharmaceutical absorption and drug washout during normal voiding can limit sustained drug concentrations in the urothelium, which reduces efficacy, and small-molecule chemotherapeutic agents can be absorbed through the urothelium into the bloodstream, leading to systemic adverse effects. Several novel drug delivery methods - including hyperthermia, mechanical sustained released devices and nanoparticle drug conjugation - have been developed to overcome these limitations. These novel methods have the potential to be combined with established chemotherapeutic agents to change the paradigm of NMIBC treatment.

Current advances in BCG-unresponsive non-muscle invasive bladder cancer

Introduction: The current first line therapy for high grade (HG) non-muscle invasive bladder cancer (NMIBC) is intravesical Bacillus Calmette-Guerin (BCG). Patients who recur or progress despite BCG are recommended to undergo radical cystectomy or participate in clinical trials. There is an urgent need for alternative therapies in the BCG-unresponsive NMIBC realm. Areas covered: We queried clinicaltrials.gov and pubmed.gov for current and recently completed early clinical trials pertaining to investigational agents used for the treatment of BCG-unresponsive NMIBC. These included intravesical chemotherapy, immunotherapy, vaccines, gene therapy, viruses, and agents used with novel drug delivery methods. In this article, we discuss the treatment guidelines for non-muscle invasive bladder cancer and therapeutic approaches under investigation in clinical trials. Expert opinion: The FDA is currently allowing single-arm studies as a pathway for approval in BCG-refractory patients with CIS. Although many agents are currently undergoing testing, none have been approved since Valrubicin. Hopefully, we will identify therapies sufficiently effective and durable to achieve FDA approval. Other considerations in this realm include the use of biomarkers in NMIBC to identify patients who will most likely respond to specific interventions. In addition, as systemic agents such as checkpoint inhibitors, are studied further, a multidisciplinary approach may be needed to treat this subset of patients.

Current Therapeutic Strategies in Clinical Urology

The field of urology encompasses all benign and malignant disorders of the urinary tract and the male genital tract. Urological disorders convey a huge economic and patient quality-of-life burden. Hospital acquired urinary tract infections, in particular, are under scrutiny as a measure of hospital quality. Given the prevalence of these pathologies, there is much progress still to be made in available therapeutic options in order to minimize side effects and provide effective care. Current drug delivery mechanisms in urological malignancy and the benign urological conditions of overactive bladder (OAB), interstitial cystitis/bladder pain syndrome (IC/BPS), and urinary tract infection (UTI) will be reviewed herein. Both systemic and local therapies will be discussed including sustained release formulations, nanocarriers, hydrogels and other reservoir systems, as well as gene and immunotherapy. The primary focus of this review is on agents which have passed the preclinical stages of development.

Advances in risk stratification of bladder cancer to guide personalized medicine

Bladder cancer is a heterogeneous disease that poses unique challenges to the treating clinician. It can be limited to a relatively indolent papillary tumor with low potential for progression beyond this stage to muscle-invasive disease prone to distant metastasis. The former is best treated as conservatively as possible, whereas the latter requires aggressive surgical intervention with adjuvant therapies in order to provide the best clinical outcomes. Risk stratification traditionally uses clinicopathologic features of the disease to provide prognostic information that assists in choosing the best therapy for each individual patient. For bladder cancer, this informs decisions regarding the type of intravesical therapy that is most appropriate for non-muscle-invasive disease or whether or not to administer neoadjuvant chemotherapy prior to radical cystectomy. More recently, tumor genetic sequencing data have been married to clinical outcomes data to add further sophistication and personalization. In the next generation of risk classification, we are likely to see the inclusion of molecular subtyping with specific treatment considerations based on a tumor’s mutational profile.

Lumbrokinase/paclitaxel nanoparticle complex: potential therapeutic applications in bladder cancer

Background

Lumbrokinase (LK) is an enzyme complex with antithrombotic, antioxidant, antitumor, and immunomodulatory effects. It has been extensively studied and used in clinical anti-tumor therapy. However, its half-life is short, its bioavailability is low, and its toxicity and side effects are great, which greatly limit its clinical application. Therefore, LK is often combined with other drugs (such as immune agents, hormones, or Chinese herbal medicine) to reduce its dosage and side effects and to improve its anti-tumor effects.

Methods and results

Here, we described an LK/paclitaxel (PTX) nanocarrier based on poly(ethylene glycol)-b-(poly(ethylenediamine l-glutamate)-g-poly(ε-benzyoxycarbonyl-l-lysine)-r-poly(l-lysine)) (PEG-b-(PELG-g-(PZLL-r-PLL))). In the present study, LK and PTX were loaded by electrostatic and/or hydrophobic effects under mild conditions, thereby increasing the half-life and bioavailability of the drugs via the sustained release and enhancement of tumor site enrichment by the LK/PTX/PEG-b-(PELG-g-(PZLL-r-PLL)) complex through passive targeting. In this study, using bladder cancer cells (J82 cells) and rat bladder cancer model as the object, the structure of the nanocarrier, the relationship between drugs composition and antitumor properties were systematically studied.

Conclusion

We propose that the block copolymer PEG-b-(PELG-g-(PZLL-r-PLL)) may function as a potent nanocarrier for augmenting anti-bladder cancer pharmacotherapy, with unprecedented clinical benefits.

Current clinical trials in non-muscle invasive bladder cancer

BACKGROUND

The treatment options for non-muscle invasive bladder cancer (NMIBC) remain limited. Bacillus Calmette-Guerin (BCG) was the last major breakthrough in bladder cancer therapy almost 4 decades ago. There have been improvements in the understanding of immune therapies and cancer biology, leading to the development of novel agents. This has led to many clinical trials that are currently underway to find the next generation of therapies for NMIBC.

METHOD

We reviewed clinicaltrials.org and pubmed.gov to find the recently completed and ongoing clinical trials in NIMBC. Included in this review are clinical trials that are currently active and trials that were completed in and after 2014.

RESULT

Many trials with BCG-naive and BCG-unresponsive/recurrent/refractory/failure patients with NMIBC are either currently underway or have been recently completed. A wide variety of novel therapeutic agents are being investigated that range from cytotoxic agents to immunomodulatory agents to targeted molecular therapies. Other approaches include cancer vaccines, gene therapies, and chemoradiation potentiation agents. Novel drug-delivery methods are also being tested.

CONCLUSION

This comprehensive update of current trials provides researchers an overview of the current clinical trial landscape for patients with NMIBC.

Nano-BCG: A Promising Delivery System for Treatment of Human Bladder Cancer

Mycobacterium bovis bacillus Calmette–Guerin (BCG) remains at the forefront of immunotherapy for treating bladder cancer patients. However, the incidence of recurrence and progression to invasive cancer is commonly observed. There are no established effective intravesical therapies available for patients, whose tumors recur following BCG treatment, representing an important unmet clinical need. In addition, there are very limited options for patients who do not respond to or tolerate chemotherapy due to toxicities, resulting in poor overall treatment outcomes. Within this context, nanotechnology is an emergent and promising tool for: (1) controlling drug release for extended time frames, (2) combination therapies due to the ability to encapsulate multiple drugs simultaneously, (3) reducing systemic side effects, (4) increasing bioavailability, (5) and increasing the viability of various routes of administration. Moreover, bladder cancer is often characterized by high mutation rates and over expression of tumor antigens on the tumor cell surface. Therapeutic targeting of these biomolecules may be improved by nanotechnology strategies. In this mini-review, we discuss how nanotechnology can help overcome current obstacles in bladder cancer treatment, and how nanotechnology can facilitate combination chemotherapeutic and BCG immunotherapies for the treatment of non-muscle invasive urothelial bladder cancer.

Alternative therapies in patients with non-muscle invasive bladder cancer

Bladder cancer (BC) is one of the leading causes of cancer-related deaths worldwide. Despite, the majority of the cases were diagnosed as non-muscle invasive bladder cancer (NMIBC) with favorable prognosis, it has tendency to recur or progress to a higher grade or stage. The first line treatment of patients with NMIBC is transurethral resection with adjuvant therapies primarily intravesical Bacillus Calmette-Guérin (BCG) immunotherapy. However, in a portion of patients whose BCG treatment failed, alternative treatments may be required. Furthermore, intravesical BCG may be contraindicated in or untolerated by a group of patients. For these patients, some treatment options are readily available and a variety of them are currently under clinical investigation. In this review, these alternative therapies have been summarized.

An open label, single-arm, phase II multicenter study of the safety and efficacy of CG0070 oncolytic vector regimen in patients with BCG-unresponsive non-muscle-invasive bladder cancer: Interim results

OBJECTIVES

CG0070 is a replication-competent oncolytic adenovirus that targets bladder tumor cells through their defective retinoblastoma pathway. Prior reports of intravesical CG0070 have shown promising activity in patients with high-grade non-muscle invasive bladder cancer (NMIBC) who previously did not respond to bacillus Calmette-Guérin (BCG). However, limited accrual has hindered analysis of efficacy, particularly for pathologic subsets. We evaluated interim results of a phase II trial for intravesical CG0070 in patients with BCG-unresponsive NMIBC who refused cystectomy.

PATIENTS AND METHODS

At interim analysis (April 2017), 45 patients with residual high-grade Ta, T1, or carcinoma-in-situ (CIS) ± Ta/T1 had evaluable 6-month follow-up in this phase II single-arm multicenter trial (NCT02365818). All patients received at least 2 prior courses of intravesical therapy for CIS, with at least 1 being a course of BCG. Patients had either failed BCG induction therapy within 6 months or had been successfully treated with BCG with subsequent recurrence. Complete response (CR) at 6 months was defined as absence of disease on cytology, cystoscopy, and random biopsies.

RESULTS

Of 45 patients, there were 24 pure CIS, 8 CIS + Ta, 4 CIS + T1, 6 Ta, 3 T1. Overall 6-month CR (95% CI) was 47% (32%-62%). Considering 6-month CR for pathologic subsets, pure CIS was 58% (37%-78%), CIS ± Ta/T1 50% (33%-67%), and pure Ta/T1 33% (8%-70%). At 6 months, the single patient that progressed to muscle-invasive disease had Ta and T1 tumors at baseline. No patients with pure T1 had 6-month CR. Treatment-related adverse events (AEs) at 6 months were most commonly urinary bladder spasms (36%), hematuria (28%), dysuria (25%), and urgency (22%). Immunologic treatment-related AEs included flu-like symptoms (12%) and fatigue (6%). Grade III treatment-related AEs included dysuria (3%) and hypotension (1.5%). There were no Grade IV/V treatment-related AEs.

CONCLUSIONS

This phase II study demonstrates that intravesical CG0070 yielded an overall 47% CR rate at 6 months for all patients and 50% for patients with CIS, with an acceptable level of toxicity for patients with high-risk BCG-unresponsive NMIBC. There is a particularly strong response and limited progression in patients with pure CIS.

Tackling non-muscle invasive bladder cancer in the clinic

INTRODUCTION

Non-muscle invasive bladder cancer (NMIBC) is a common disease process with a high propensity for recurrence and risk of progression to muscle-invasive or systemic disease. Optimal management of NMIBC depends on appropriate resection and staging, risk-based use of intravesical therapy and tailored surveillance. Current challenges include compliance with guideline recommendations and cancers which are refractory to standard therapies. Areas covered: This review summarizes the conventional management of NMIBC - which relies on strict cystoscopic surveillance and intravesical therapies with chemotherapy and/or immunotherapy in the form of bacillus Calmette-Guerin (BCG). As many patients will be resistant to conventional treatment, investigational therapies and novel prognostic models will also be discussed. Expert commentary: For decades, the management of NMIBC has been predicated on intravesical therapies, most often through the instillation of BCG which has proven clinical efficacy over transurethral resection alone. Despite this, many patients will recur or progress after BCG therapy. While radical cystectomy remains the standard for such patients, suitable alternatives are being actively investigated. An increased interest in immunotherapy for malignancy has reinvigorated this field and on-going advances in disease prognostication are likely to improve upon the existing treatment paradigms for NMIBC.

Efficacy of Mycobacterium Phlei Cell Wall-Nucleic Acid Complex (MCNA) in BCG-Unresponsive Patients

Background: We have previously reported the results of a prospective multi-institutional study on the efficacy of MCNA in patients who recurred after intravesical BCG treatment [1]. Since that publication, a new standardized definition for BCG-unresponsiveness has been established [2]. Objective: We re-analyzed the oncologic outcomes following intravesical MCNA in patients classified as BCG-unresponsive according to the new definition. Methods: For this analysis, we focused on the enrolled patients who satisfied the requirements for BCG Unresponsiveness: i.e. adequate BCG treatment (at least 5/6 induction and 2/3 maintenance instillations) and high grade tumor within 6 months of prior BCG. Treatment course included 6 weekly intravesical instillations of 8 mg MCNA followed by 3 weekly instillations at months 3, 6, 12, 18, and 24. Followup assessments included cystoscopy, urine cytology and biopsy. Patients absent of high grade disease confirmed by central review of biopsy were deemed disease-free. Results: Of the 129 patients enrolled, 94 (68 CIS with/without papillary tumors, 26 papillary only tumors) fit the criteria for the new BCG Unresponsive definition. Overall, disease free survival (DFS) for all BCG unresponsive patients was 48.9% (95% CI 38.0-59.0%) at 6 months, 34.8% (95% CI 24.7-45%) at 1 year and 28.3% (15.7-34.3%) at 2 years post induction. In the group with papillary tumors, DFS measured at months 6, 12, and 24 were: 61.2% (38.2-77.8%), 61.2(38.2-77.8%), and 50.1% (27.5-69%). In the CIS-containing group, the corresponding DFS were: 44.8% (32.3-56.4%), 26.5% (16.3-37.9%), and 16.6% (8.6-26.9%), respectively. Conclusions: For patients who are BCG Unresponsive, MCNA has the potential to render 26.5% of patients with CIS and 61.2% of patients with papillary tumors disease-free for at least 1 year with an intact bladder. The higher efficacy noted in the true BCG-unresponsive cohort than was previously reported with all-comers emphasizes the importance of having clearly defined criteria for clinical trials investigating new intravesical therapies after BCG failure.

Non-muscle-invasive bladder cancer: Intravesical treatments beyond Bacille Calmette-Guérin

An unmet need exists for patients with high-risk non-muscle-invasive bladder cancer for whom bacille Calmette-Guérin (BCG) has failed and who seek further bladder-sparing approaches. This shortcoming poses difficult management dilemmas. This review explores previously investigated first-line intravesical therapies and discusses emerging second-line treatments for the heterogeneous group of patients for whom BCG has failed. The myriad of recently published and ongoing trials assessing novel salvage intravesical treatments offer promise to patients who both seek an effective cure and want to avoid radical surgery. However, these trials must carefully be contextualized by specific patient, tumor, and recurrence characteristics. As data continue to accumulate, there will potentially be a role for these agents as second-line or even first-line intravesical therapies. Cancer 2017;123:390-400. © 2016 American Cancer Society.

The Future of Intravesical Drug Delivery for Non-Muscle Invasive Bladder Cancer

Despite being the fifth most common cancer in the United States, minimal progress has been made in the treatment of bladder cancer in over a decade. Intravesical instillation of Bacillus Calmette-Guerin (BCG) for the treatment of non-muscle invasive bladder cancer (NMIBC) has been in use for over 30 years and remains the standard treatment in cases of intermediate and high risk disease. Despite the relative success of intravesical BCG, unmet needs in the treatment of NMIBC persist. These challenges include disease recurrence and progression even with treatment with BCG, as well as issues regarding its availability and patient tolerability. The inherent properties of the bladder pose the biggest obstacle to developing effective intravesical treatments for NMIBC. Current research is now focusing on methods to improve the delivery of intravesical therapies. The objective of this review is to discuss novel intravesical drug delivery systems and how they are addressing these challenges in the treatment of NMIBC.

The role of mycobacterial cell wall nucleic acid complex in the treatment of bacillus Calmette-Guérin failures for non-muscle-invasive bladder cancer

INTRODUCTION

The treatment of high-risk non-muscle-invasive bladder cancer (NMIBC) utilizes transurethral resection followed by adjuvant intravesical immunotherapy or chemotherapy. Intravesical bacillus Calmette-Guérin (BCG) is the mainstay of adjuvant immunotherapy, but there are limited nonsurgical options for patients that fail this treatment. Mycobacterial cell wall nucleic acid complex (MCNA) is an immunotherapeutic agent utilized primarily after failure of intravesical BCG. The purpose of this paper is to provide a comprehensive review of the published literature regarding MCNA.

METHODS

A literature review was performed and identified studies indexed in MEDLINE(®) related to utilization of MCNA for patients with NMIBC.

RESULTS

Two trials assessed the efficacy of MCNA in patients with NMIBC, comprising a total of 184 patients. Most patients had carcinoma in situ (CIS) with (26%) or without (52%) concomitant papillary tumors. A minority of patients had only papillary tumors (22%). Most patients (95%) previously received BCG or other intravesical therapy prior to receiving MCNA. In the largest available trial, 25% and 19% of patients had no evidence of residual cancer in 1 and 2 years following initiation of MCNA. A total of 2.3% of patients had adverse events (AEs) leading to delay or discontinuation of therapy and 66% of patients had mild drug-related AEs.

CONCLUSION

Based on analysis of available published data, MCNA offers a durable response for a small proportion of patients that have failed prior intravesical therapy. There still exists a large unmet need for nonsurgical treatment options for patients with NMIBC who have failed adjuvant intravesical therapies.

Bacille-Calmette-Guerin non-responders: how to manage

Intravesical immunotherapy with bacille-Calmette-Guerin (BCG) is indicated in the treatment of high-risk and intermediate-risk non-muscle invasive bladder cancer (NMIBC). Our goal is to describe the various disease states following induction and maintenance BCG and to describe contemporary treatment options and the current and projected clinical trial landscape for patients who recur following BCG therapy.

Intravesical and alternative bladder-preservation therapies in the management of non-muscle-invasive bladder cancer unresponsive to bacillus Calmette-Guérin

Intravesical Bacillus Calmette-Guérin (BCG) remains the standard of care in the treatment of bladder carcinoma in situ and as adjuvant therapy after thorough transurethral resection of high-grade non-muscle-invasive bladder cancer. Despite BCG therapy, in up to 40% of patients it would recur and 60% to 70% of those would fail repeat BCG induction be deemed BCG unresponsive. For such patients, cystectomy remains the preferred treatment option per the American Urological Association and European Association of Urology, though some patients would be medically unfit or refuse radical surgery. Further intravesical therapy for bladder-preservation therapies may preserve quality of life in these patients and in some cases can be curative. There are numerous non-BCG intravesical salvage options available, including immunotherapy, single-agent chemotherapy, combination chemotherapy, and device-assisted chemotherapy. In addition, investigation of radiation-based treatment and other novel therapies including checkpoint inhibitors (programmed death-1/programmed death ligand-1), are currently underway. In this review, we examine the current status of alternatives to BCG in salvage therapy for bladder preservation.