Intravesical valrubicin in patients with bladder carcinoma in situ and contraindication to or failure after bacillus Calmette-Guérin

Developments in conservative treatment for BCG-unresponsive non-muscle invasive bladder cancer

INTRODUCTION

To reduce the risk of disease recurrence and progression of intermediate and high-risk Non-Muscle Invasive Bladder Cancers (NMIBCs), intravesical adjuvant treatment with Bacillus Calmette-Guerin (BCG) represents the standard of care, although up to 50% of patients will eventually recur and up to 20% of them will progress to Muscle Invasive Bladder Cancer (MIBC). Radical Cystectomy (RC) is the treatment of choice in this setting; however, this represents a major and morbid surgery, thus meaning that not all NMIBCs patient could undergo or may refuse this procedure or may refuse. The search for effective bladder sparing strategies in NMIBCs BCG-unresponsive patients is a hot topic in the urologic field.

AREAS COVERED

We aimed to review the most important bladder-preserving strategies for BCG unresponsive disease, from those used in the past, even though rarely used nowadays (intravesical chemotherapy with single agents), to current available therapies (e.g. intravesical instillation with Gemcitabine-Docetaxel), and to future upcoming treatments (Oportuzumab Monatox).

EXPERT OPINION

At present, bladder-preserving treatments in BCG-unresponsive patients are represented by the use of intravesical instillations, systemic immunotherapies, both with good short-term and modest mid-term efficacy, and numerous clinical trials ongoing, with encouraging initial results, in which patients could be recruited.

Valrubicin-loaded immunoliposomes for specific vesicle-mediated cell death in the treatment of hematological cancers

We created valrubicin-loaded immunoliposomes (Val-ILs) using the antitumor prodrug valrubicin, a hydrophobic analog of daunorubicin. Being lipophilic, valrubicin readily incorporated Val-lLs that were loaded with specific antibodies. Val-ILs injected intravenously rapidly reached the bone marrow and spleen, indicating their potential to effectively target cancer cells in these areas. Following the transplantation of human pediatric B-cell acute lymphoblastic leukemia (B-ALL), T-cell acute lymphoblastic leukemia (T-ALL), or acute myeloid leukemia (AML) in immunodeficient NSG mice, we generated patient-derived xenograft (PDX) models, which were treated with Val-ILs loaded with antibodies to target CD19, CD7 or CD33. Only a small amount of valrubicin incorporated into Val-ILs was needed to induce leukemia cell death in vivo, suggesting that this approach could be used to efficiently treat acute leukemia cells. We also demonstrated that Val-ILs could reduce the risk of contamination of CD34+ hematopoietic stem cells by acute leukemia cells during autologous peripheral blood stem cell transplantation, which is a significant advantage for clinical applications. Using EL4 lymphoma cells on immunocompetent C57BL/6 mice, we also highlighted the potential of Val-ILs to target immunosuppressive cell populations in the spleen, which could be valuable in impairing cancer cell expansion, particularly in lymphoma cases. The most efficient Val-ILs were found to be those loaded with CD11b or CD223 antibodies, which, respectively, target the myeloid-derived suppressor cells (MDSC) or the lymphocyte-activation gene 3 (LAG-3 or CD223) on T4 lymphocytes. This study provides a promising preclinical demonstration of the effectiveness and ease of preparation of Val-ILs as a novel nanoparticle technology. In the context of hematological cancers, Val-ILs have the potential to be used as a precise and effective therapy based on targeted vesicle-mediated cell death.

Multidisciplinary consensus document on the current treatment of bacille Calmette-Guérin-unresponsive non-muscle invasive bladder tumor

Radical cystectomy is the current treatment of choice for patients with BCG-unresponsive non-muscle invasive bladder tumor (NMIBC). However, the high comorbidity of this surgery and its effects on the quality of life of patients require the investigation and implementation of bladder-sparing treatment options. These must be evaluated individually by the uro-oncology committee based on the characteristics of the BCG failure, type of tumor, patient preferences and treatment options available in each center. Based on FDA-required oncologic outcomes (6-month complete response rate for CIS: 50%; duration of response in responders for CIS and papillary: 30% at 12 months and 25% at 18 months), there is not currently a strong preference for one treatment over another, although the intravesical route seems to offer less toxicity. This work summarizes the evidence on the management of BCG-unresponsive NMIBC based on current scientific evidence and provides consensus recommendations on the most appropriate treatment.

Phase 2 Trial of Atezolizumab in Bacillus Calmette-Guérin-unresponsive High-risk Non-muscle-invasive Bladder Cancer: SWOG S1605

BACKGROUND

Although radical cystectomy (RC) is the standard of care for patients with bacillus Calmette-Guérin (BCG)-unresponsive high-risk non-muscle-invasive bladder cancer (NMIBC), many patients are ineligible for surgery or elect bladder preservation.

OBJECTIVE

To evaluate the efficacy and safety of atezolizumab in BCG-unresponsive high-risk NMIBC.

DESIGN, SETTING, AND PARTICIPANTS

This was a single-arm phase 2 trial in patients with BCG-unresponsive high-risk NMIBC who were ineligible for or declined RC.

INTERVENTION

Intravenous atezolizumab every 3 wk for 1 yr.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was the pathological complete response (CR) rate for patients with carcinoma in situ (CIS) determined via mandatory biopsy at 6 mo. Event-free survival (EFS) at 18 mo for patients with non-CIS tumors and treatment-related adverse events (TRAEs) were key secondary endpoints.

RESULTS AND LIMITATIONS

Of 172 patients enrolled in the trial, 166 received at least one dose of atezolizumab (safety analysis) and 129 were eligible (efficacy analysis). Of the 74 patients with CIS, 20 (27%) experienced a CR at 6 mo. The median duration of response was 17 mo, and 56% (95% confidence interval [CI] 34-77%) of the responses were durable to at least 12 mo. The 18-mo actuarial EFS rate among 55 patients with Ta/T1 disease was 49% (90% CI 38-60%). Twelve of 129 eligible patients experienced progression to muscle-invasive or metastatic disease. Grade 3-5 TRAEs occurred in 26 patients (16%), including three treatment-related deaths. The study was limited by the small sample size and a high rate of patient ineligibility.

CONCLUSIONS

The efficacy of atezolizumab observed among patients with BCG-unresponsive NMIBC is similar to results from similar trials with other agents, but did not meet the prespecified efficacy threshold. Modest efficacy needs to be balanced with a significant rate of TRAEs and the risk of disease progression when considering systemic immunotherapy in early-stage bladder cancer.

PATIENT SUMMARY

We tested intravenous immunotherapy (atezolizumab) in patients with high-risk non-muscle-invasive bladder cancer that recurred after BCG (bacillus Calmette-Guérin) treatment. Although we found similar outcomes to previous trials, the benefit of this therapy is modest and needs to be carefully balanced with the significant risk of side effects. This trial is registered on ClinicalTrials.gov as NCT02844816.

A Critical Analysis of the FDA's Omics-Driven Pharmacodynamic Biomarkers to Establish Biosimilarity

Demonstrating biosimilarity entails comprehensive analytical assessment, clinical pharmacology profiling, and efficacy testing in patients for at least one medical indication, as required by the U.S. Biologics Price Competition and Innovation Act (BPCIA). The efficacy testing can be waived if the drug has known pharmacodynamic (PD) markers, leaving most therapeutic proteins out of this concession. To overcome this, the FDA suggests that biosimilar developers discover PD biomarkers using omics technologies such as proteomics, glycomics, transcriptomics, genomics, epigenomics, and metabolomics. This approach is redundant since the mode-action-action biomarkers of approved therapeutic proteins are already available, as compiled in this paper for the first time. Other potential biomarkers are receptor binding and pharmacokinetic profiling, which can be made more relevant to ensure biosimilarity without requiring biosimilar developers to conduct extensive research, for which they are rarely qualified.

Recent advancements in the diagnosis and treatment of non-muscle invasive bladder cancer: Evidence update of surgical concept, risk stratification, and BCG-treated disease

In the management of non-muscle invasive bladder cancer (NMIBC), disease progression and long-term control are determined by the intensity of delivered treatment and surveillance and the cancer cells' biological nature. This requires risk stratification-based postoperative management, such as intravesical instillation of chemotherapy drugs, Bacillus Calmette-Guérin (BCG), and radical cystectomy. Advancements in mechanical engineering, molecular biology, and surgical skills have evolved the clinical management of NMIBC. In this review, we describe the updated evidence and perspectives regarding the following aspects: (1) advancements in surgical concepts, techniques, and devices for transurethral resection of the bladder tumor; (2) advancements in risk stratification tools for NMIBC; and (3) advancements in treatment strategies for BCG-treated NMIBC. Repeat transurethral resection, en-bloc transurethral resection, and enhanced tumor visualization, including photodynamic diagnosis and narrow-band imaging, help reduce residual cancer cells, provide accurate diagnosis and staging, and sensitive detection, which are the first essential steps for cancer cure. Risk stratification should always be updated and improved because the treatment strategy changes over time. The BCG-treated disease concept has recently diversified to include BCG failure, resistance, refractory, unresponsiveness, exposure, and intolerance. A BCG-unresponsive disease is an extremely aggressive subset unlikely to respond to a rechallenge with BCG. Numerous ongoing clinical trials aim to develop a future bladder-sparing approach for very high-risk BCG-naïve NMIBC and BCG-unresponsive NMIBC. The key to improving the quality of patient care lies in the continuous efforts to overcome the clinical limitations of bedside management.

A Phase II Study of Durvalumab for Bacillus Calmette-Guerin (BCG) Unresponsive Urothelial Carcinoma In Situ of the Bladder

PURPOSE

Immune checkpoint blockade holds promise for treating bacillus Calmette-Guerin (BCG)-unresponsive non-muscle-invasive bladder cancer (NMIBC). In this phase II study, we investigated the safety and efficacy of durvalumab, a human IgG1 monoclonal antibody, against BCG-unresponsive carcinoma in situ (CIS).

PATIENTS AND METHODS

Patients with BCG-unresponsive CIS-containing NMIBC received durvalumab IV at 1,500 mg every 4 weeks for up to 12 months. The primary endpoint was complete response (CR) rate at month 6, defined by negative cystoscopy, urine cytology, and absence of high-grade recurrence on bladder mapping biopsy. The null hypothesis specified a CR rate of 18% and alternative hypothesis of 40%. According to the Simon two-stage design, if ≤3/13 patients achieved CR during stage 1, the trial is stopped due to futility.

RESULTS

Between March 8, 2017, and January 24, 2020, 17 patients were accrued whereas 4 withdrew from study treatment after bladder biopsy at month 3 was positive for CIS. Two of 17 (12%) achieved a CR at month 6, with duration of response of 10 and 18 months, respectively. A single grade 3 lipase elevation was attributed to durvalumab, and immune-related adverse events were observed in 7/17 (41%) patients. Only 1/17 patients had high programmed death-ligand 1 expression pretreatment. On RNA sequencing, complement activation genes were elevated posttreatment, along with enrichment of tumor-associated macrophage signature.

CONCLUSIONS

Durvalumab monotherapy conferred minimal efficacy in treating BCG-unresponsive CIS of the bladder, with 6-month CR of 12%. Complement activation is a potential mechanism behind treatment resistance.

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.

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.

Cost-Effectiveness of Nadofaragene Firadenovec and Pembrolizumab in Bacillus Calmette-Guérin Immunotherapy Unresponsive Non-Muscle Invasive Bladder Cancer

OBJECTIVES

Nadofaragene firadenovec is a gene therapy for bacillus Calmette-Guérin (BCG)-unresponsive non-muscle-invasive bladder cancer (NMIBC) undergoing Food and Drug Administration review. Pembrolizumab is approved for treating patients with BCG-unresponsive NMIBC with carcinoma in situ (CIS). We evaluated the cost-effectiveness of these treatments compared with a hypothetical therapeutic alternative, at a willingness-to-pay threshold of $150 000 per quality-adjusted life-year (QALY) gained, in CIS and non-CIS BCG-unresponsive NMIBC populations.

METHODS

We developed a Markov cohort simulation model with a 3-month cycle length and lifetime horizon to estimate the total costs, QALYs, and cost per additional QALY from the health sector perspective. Clinical inputs were informed by results of single-arm clinical trials evaluating the treatments, and systematic literature reviews were conducted to obtain other model inputs. Sensitivity analyses were conducted to assess uncertainty in model results.

RESULTS

Nadofaragene firadenovec, at a placeholder price 10% higher than the price of pembrolizumab, had an incremental cost-effectiveness ratio of $263 000 and $145 000 per QALY gained in CIS and non-CIS populations, respectively. Pembrolizumab had an incremental cost-effectiveness ratio of $168 000 per QALY gained for CIS. A 5.4% reduction in pembrolizumab's price would make it cost-effective. The model was sensitive to many inputs, especially to the probabilities of disease progression, initial treatment response and durability, and drug price.

CONCLUSIONS

The cost-effectiveness of nadofaragene firadenovec will depend upon its price. Pembrolizumab, although not cost-effective in our base-case analysis, is an important alternative in this population with an unmet medical need. Comparative trials of these treatments are warranted to better estimate cost-effectiveness.

Lentiviral interferon: A novel method for gene therapy in bladder cancer

Interferon alpha (IFNα) gene therapy is emerging as a new treatment option for patients with non-muscle invasive bladder cancer (NMIBC). Adenoviral vectors expressing IFNα have shown clinical efficacy treating bacillus Calmette-Guerin (BCG)-unresponsive bladder cancer (BLCA). However, transient transgene expression and adenoviral immunogenicity may limit therapeutic activity. Lentiviral vectors can achieve stable transgene expression and are less immunogenic. In this study, we evaluated lentiviral vectors expressing murine IFNα (LV-IFNα) and demonstrate IFNα expression by transduced murine BLCA cell lines, bladder urothelium, and within the urine following intravesical instillation. Murine BLCA cell lines (MB49 and UPPL1541) were sensitive to IFN-mediated cell death after LV-IFNα, whereas BBN975 was inherently resistant. Upregulation of interleukin-6 (IL-6) predicted sensitivity to IFN-mediated cell death mediated by caspase signaling, which when inhibited abrogated IFN-mediated cell killing. Intravesical therapy with LV-IFNα/Syn3 in a syngeneic BLCA model significantly improved survival, and molecular analysis of treated tumors revealed upregulation of apoptotic and immune-cell-mediated death pathways. In particular, biomarker discovery analysis identified three clinically actionable targets, PD-L1, epidermal growth factor receptor (EGFR), and ALDHA1A, in murine tumors treated with LV-IFNα/Syn3. Our findings warrant the comparison of adenoviral and LV-IFNα and the study of novel combination strategies with IFNα gene therapy for the BLCA treatment.

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.

Real-world treatment patterns and oncological outcomes in early relapse and refractory disease after bacillus Calmette-Guérin failure in non-muscle-invasive bladder cancer

OBJECTIVE

To assess real-world oncological outcomes between the radical cystectomy (RC) group and non-RC group for early relapse and refractory disease.

METHODS

We retrospectively analyzed 953 patients with recurrent non-muscle-invasive bladder cancer (NMIBC) who received bacillus Calmette-Guérin (BCG) at 31 affiliated hospitals from 2000 to 2019. Patients with missing data on the timing of failure were excluded and 871 patients remained eligible, of whom 447, 357, and 67 were classified as early relapse/refractory disease, intermediate/late relapse disease, and intolerant disease, respectively. For early relapse/refractory disease, patients were divided into two salvage treatment groups: RC and non-RC. The clinicopathological variables of each group were examined using Kaplan-Meier plots and proportional Cox hazard ratios with matched score analyses to compare oncological outcomes between the two groups.

RESULTS

Significantly worse progression-free survival and cancer-specific survival (CSS) were confirmed in the early relapse/refractory disease group compared to the intermediate/late relapse group. Of the 88 salvage patients in the RC group with early relapse/refractory disease, ≤pT1 was observed in 47, pT2 in 11, and ≥pT3 in 28 (two patients with unknown pT category). In early relapse/refractory disease, the RC group showed significantly high-risk tumor compared to the non-RC group. However, no significant difference was observed in CSS after matched score analyses (p = 0.45) between the RC and non-RC groups.

CONCLUSIONS

This study found that the RC group showed no significant superiority compared to the non-RC group in CSS for early relapse/refractory disease in terms of first salvage therapy.

Emerging treatment landscape of non-muscle invasive bladder cancer

INTRODUCTION

Non-muscle invasive bladder cancer (NMIBC) accounts for 70-75% of all bladder cancers and is a heterogeneous disease characterized by a wide spectrum of recurrences and progression. Adjuvant treatment for intermediate- and high-risk NMIBC is mainly represented by Bacillus Calmette Guerin (BCG). However, 20%-40% of patients develop disease recurrences or persistence following BCG treatment and are classified as "BCG unresponsive' (BCGu), thus representing a therapeutic challenge due to their worse prognosis and unavailability of effective intravesical treatments.

AREAS COVERED

We provide an overview of completed and ongoing clinical trials assessing the role of innovative immunological and target agents in patients with BCGu and BCG naive (BCGn) NMIBCs. New treatment options are emerging, demonstrating promising clinical activity, namely, pembrolizumab, atezolizumab, oportuzumab monatox, nadofaragene firadenovec, and N-803.

EXPERT OPINION

The increasing number of newer therapeutic agents for patients with NMIBC poses challenges regarding the choice of the most suited treatment option for each patient and the best treatment sequence, given their diverse mechanisms of action and varying degrees of activity. Tailored treatment approaches are advocated, based on a deeper comprehension of disease features, available therapies, patient's characteristics, and consequently, on the identification and validation of prognostic and predictive biomarkers.

Oncofid-P-B: a novel treatment for BCG unresponsive carcinoma in situ (CIS) of the bladder: Results of a prospective European Multicentre study at 15 months from treatment start

PURPOSE

This study reports the safety and efficacy of Oncofid^-P-B, a novel compound under development by Fidia Farmaceutici S.p.A. with specific binding to CD44 receptor, in patients with CIS unresponsive or intolerant to BCG.

MATERIALS AND METHODS

This is a phase 1 open-label, single arm, multicenter European study to assess safety, tolerability and efficacy of Oncofid-P-B administered in 20 patients with CIS ± Ta-T1, unresponsive or intolerant to BCG, unwilling or unfit for cystectomy. Oncofid-P-B was administered by intravesical instillation for 12 consecutive weeks (intensive phase) followed, in CR patients, by 12 monthly instillations (maintenance phase). The primary objective was the overall safety profile. Secondary objectives included: i) any evidence of antitumor activity, ii) patient's compliance, iii) systemic absorption. The CR was defined as a negative cystoscopy, negative biopsy of the urothelium and negative cytology.

RESULTS

At the end of the intensive phase, 15 of the 20 enrolled patients (75%), achieved the CR. Patients still in CR after 3, 6, 9 and 12 months of maintenance phase were 13 (65%), 12 (60%), 9 (45%) and 8 (40%), respectively. Only seven (5 mild and 2 moderate) drug-related AEs were reported in three patients. No drug related serious AEs and no drug related withdrawals have been reported. In all plasma samples, the drug concentratiosn was below the LLOQ (1ng/ml).

CONCLUSIONS

Oncofid-P-B is very safe, well tolerated and highly effective (75% CR) when administered weekly for up to 12 consecutive weeks (75% CR), with 40% CR still after 15 months from treatment start.

Novel and emerging approaches in the management of non-muscle invasive urothelial carcinoma

Non-muscle invasive bladder cancer (NMIBC) has traditionally been managed with transurethral resection followed by intravesical chemotherapy and/or bacillus Calmette-Guerin (BCG) in a risk-adapted manner. These tumors commonly recur and can progress potentially to lethal muscle invasive disease. A major unmet need in the field of NMIBC is bladder preserving therapy for recurrent high-grade NMIBC after adequate intravesical BCG therapy. The current gold standard treatment for these BCG-unresponsive patients is radical cystectomy, which is associated with considerable morbidity and mortality, particularly in older and frailer patients. It is therefore critical to provide alternative treatment options with acceptable oncological outcomes. In this review we explore novel bladder-sparing treatment options including combination intravesical therapy, enhanced instillation methods, immunotherapy, gene therapy, targeted therapy, photodynamic therapy and BCG variants across the spectrum of NMIBC disease states, ranging from low grade BCG-naïve patients through to high-grade BCG-unresponsive NMIBC.

Contemporary outcomes of bladder carcinoma in situ treated with an adequate bacille Calmette-Guérin immunotherapy

OBJECTIVE

To assess whether bacillus Calmette-Guérin (BCG) responsiveness after initiation of an adequate BCG treatment (at least five of six instillations of induction and at least two of three instillations of maintenance) impacts oncological outcomes in patients with carcinoma in situ (CIS) of the bladder treated with BCG immunotherapy.

PATIENTS AND METHODS

Data were available for 193 patients with bladder CIS with or without associated cTa/cT1 disease who received an adequate BCG treatment between 2008 and 2015. Bladder biopsies were taken at 6 months and patients were then stratified as either BCG responsive (negative biopsies) or BCG unresponsive (positive biopsies). Inverse probability weighting (IPW)-adjusted Kaplan-Meier and IPW-adjusted Cox regression were performed to compare progression-free survival (PFS), radical cystectomy-free survival (RCFS), overall survival OS, and cancer-specific survival (CSS) in the two groups.

RESULTS AND LIMITATIONS

Comparing the BCG-responsive and BCG-unresponsive groups, IPW-adjusted Kaplan-Meier analysis revealed, respectively, a median (interquartile range) of PFS of 9 (5-15) vs 48.5 (28-77) months (P = 0.001), a RCFS of 11 (9-15) vs 49 (24-76) months (P < 0.001), and a CSS of 25 (13-60) vs 109 (78-307) months (P = 0.004). On IPW-adjusted Cox regression analysis, BCG-unresponsive patients had a worse PFS (hazard ratio [HR] 3.40, 95% confidence interval [CI] 1.59-7.27), RCFS (HR 3.52, 95% CI 1.77-7), and CSS (HR 4.42, 95% CI 1.95-10.01). We found no significant differences for OS.

CONCLUSION

Using an IPW method we found that lack of response after initiation of an adequate BCG treatment has prognostic implications beyond identification of complete response in patients with CIS. BCG-unresponsive patients, satisfying the novel definition of BCG unresponsive, showed a poor PFS, RCFS, and CSS. In this setting, the patients should be counselled regarding RC as a first option or enrolled in a clinical trial if they refuse RC or are unfit for surgery.

A 25-year perspective on advances in an understanding of the biology, evaluation, treatment and future directions/challenges of urothelial cancer

The Urologic Oncology Journal was founded 25 years ago and we reviewed the literature since that time in the area of urothelial cancer to see the progress and pitfalls we have made over this time period. A comprehensive literature search was conducted by the authors involved who are all actively involved in research, clinical trials, and treatment for urothelial cancer and the results were summarized over the past 25 years. The field of urothelial cancer has evolved tremendously in the last 25 years with the incorporation of molecular subtyping, novel imaging, immunotherapy, and robotic surgery. However, treatments such as BCG and radical cystectomy have remained steadfast over the last 25 years. Although we have a better understanding of the biology of bladder cancer, we still have a long way from being able to cure patients with bladder cancer and eliminate morbidity from treatments. Nevertheless, considerable progress has been made since the founding of the Urologic Oncology Journal 25 years ago.

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.

Pembrolizumab monotherapy for the treatment of high-risk non-muscle-invasive bladder cancer unresponsive to BCG (KEYNOTE-057): an open-label, single-arm, multicentre, phase 2 study

BACKGROUND

Standard treatment for high-risk non-muscle-invasive bladder cancer is transurethral resection of bladder tumour followed by intravesical BCG immunotherapy. However, despite high initial responses rates, up to 50% of patients have recurrence or become BCG-unresponsive. PD-1 pathway activation is implicated in BCG resistance. In the KEYNOTE-057 study, we evaluated pembrolizumab, a PD-1 inhibitor, in BCG-unresponsive non-muscle-invasive bladder cancer.

METHODS

We did this open-label, single-arm, multicentre, phase 2 study in 54 sites (hospitals and cancer centres) in 14 countries. In cohort A of the trial, adults aged 18 years or older with histologically confirmed BCG-unresponsive carcinoma in situ of the bladder, with or without papillary tumours, with an Eastern Cooperative Oncology Group performance status of 0-2, and who were ineligible for or declined radical cystectomy were enrolled. All enrolled patients were assigned to receive pembrolizumab 200 mg intravenously every 3 weeks for up to 24 months or until centrally confirmed disease persistence, recurrence, or progression; unacceptable toxic effects; or withdrawal of consent. The primary endpoint was clinical complete response rate (absence of high-risk non-muscle-invasive bladder cancer or progressive disease), assessed by cystoscopy and urine cytology approximately 3 months after the first dose of study drug. Patient follow-ups were done every 3 months for the first 2 years and every 6 months thereafter for up to 5 years. Efficacy was assessed in all patients who received at least one dose of the study drug and met BCG-unresponsive criteria. Safety was assessed in all patients who received at least one dose of the study drug. This trial is registered with ClinicalTrials.gov number, NCT02625961, and is ongoing.

FINDINGS

Between Dec 9, 2015, and April 1, 2018, we screened 334 patients for inclusion. 186 patients did not meet inclusion criteria, and 47 patients were assigned to cohort B (patients with BCG-unresponsive high grade Ta or any grade T1 papillary disease without carcinoma in situ; results will be reported separately). 101 eligible patients were enrolled and assigned to receive pembrolizumab. All 101 patients received at least one dose of the study drug and were included in the safety analysis. Five patients had disease that did not meet the US Food and Drug Administration definition of BCG-unresponsive non-muscle-invasive bladder cancer and were therefore not included in the efficacy analysis (n=96). Median follow-up was 36·4 months (IQR 32·0-40·7). 39 (41%; 95% CI 30·7-51·1) of 96 patients with BCG-unresponsive carcinoma in situ of the bladder with or without papillary tumours had a complete response at 3 months. Grade 3 or 4 treatment-related adverse events occurred in 13 (13%) patients; the most common were arthralgia (in two [2%] patients) and hyponatraemia (in three [3%] patients). Serious treatment-related adverse events occurred in eight (8%) patients. There were no deaths that were considered treatment related.

INTERPRETATION

Pembrolizumab monotherapy was tolerable and showed promising antitumour activity in patients with BCG-unresponsive non-muscle-invasive bladder cancer who declined or were ineligible for radical cystectomy and should be considered a a clinically active non-surgical treatment option in this difficult-to-treat population.

FUNDING

Merck Sharp & Dohme.

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.

BCG-unresponsive high-grade non-muscle invasive bladder cancer: what does the practicing urologist need to know?

Purpose

Bacille Calmette-Guérin (BCG) is a well-established treatment for preventing or delaying tumour recurrence following high-grade nonmuscle invasive bladder cancer (NMIBC) resection. However, many patients will experience recurrence or progression during or following BCG. This scenario has been one of the most challenging in urologic oncology for several decades since BCG implementation. Finally, significant progress has occurred lately. The aim of this review was to summarize for the practising urologist the current treatment options available in 2020 or expected to be ready for routine use in the near future for patients with high-risk NMIBC who experience BCG failure.

Methods

Narrative review using data through the end of 2020.

Results

First, the definition of BCG unresponsive disease which is critical in counseling and managing patients has finally reached a consensus. Second, some promising options other than radical cystectomy are finally available and many other should be in a near future. The options can be categorized as chemotherapy, device-assisted therapy, check-point inhibitors, new intravesical and systemic agents and sequential combinations of these newer modalities with conventional therapy.

Conclusions

Considering the options that are currently under scrutiny, many of which in phase III trials, clinicians should have at their disposal several new treatment options in the next five years.

Current treatments for BCG failure in non-muscle invasive bladder cancer (NMIBC)

The treatment of choice for high-risk non-muscle invasive bladder cancer (NMIBC) is bacillus Calmette-Guérin (BCG). However, when this fails, the indicated treatment is radical cystectomy. In recent years, trials are being developed with various drugs to avoid this surgery in patients with BCG failure. The aim of this article is to update the treatments under study for bladder preservation in this patient population. Non-systematic review, searching PubMed with the terms "Bladder cancer", "Non-muscle invasive bladder cancer", "NMIBC", "BCG", "BCG-refractory", "Mitomycin C", "MMC", "Hyperthermia", "Electromotive Drug Administration", "EMDA". We used the search engines clinicaltrials.gov and clinicaltrialsregister.eu to find clinical trials. The only intravesical drug approved by the Food and Drug Administration (FDA) for carcinoma in situ (CIS) after failure to BCG is Valrubicin. Recently, the FDA has approved intravenous Pembrolizumab, following the publication of preliminary data from the KEYNOTE-057 study. Atezolizumab has demonstrated similar preliminary efficacy results. Only microwave-induced chemohyperthermia and EMDA-MMC (Electromotive Drug Administration) are recognized as alternatives in European guidelines. Other options under investigation are taxanes and gemcitabine, alone or in combination, recombinant viruses and device-assisted intravesical chemohyperthermia. The results of new drugs are promising, with a large number of trials underway. Knowing the mechanisms of resistance to BCG is essential to explore new therapeutic options.

The association of salvage intravesical therapy following BCG with pathologic outcomes and survival after radical cystectomy for patients with high-grade non-muscle invasive bladder cancer: A multi-institution analysis

INTRODUCTION

While numerous current clinical trials are testing novel salvage therapies (ST) for patients with recurrent nonmuscle invasive bladder cancer (NMIBC) after bacillus Calmette-Guérin (BCG), the natural history of this disease state has been poorly defined to date. Herein, we evaluated oncologic outcomes in patients previously treated with BCG and ST who subsequently underwent radical cystectomy (RC).

METHODS

We identified 378 patients with high-grade NMIBC who received at least one complete induction course of BCG (n = 378) with (n = 62) or without (n = 316) additional ST and who then underwent RC between 2000 and 2018. Oncologic outcomes were compared using the Kaplan-Meier method and Cox proportional hazards models. Sensitivity analyses were conducted stratifying by presenting tumor stage, matched 1:3 for receipt vs. no receipt of ST.

RESULTS

Patients receiving ST were more likely to initially present with CIS (26% vs. 17%) and less likely with T1 disease (34% vs. 50%, P = 0.06) compared to patients not treated with ST. Receipt of ST was not associated with increased risk of adverse pathology (≥pT2 or pN+) at RC (31% vs. 41%, P = 0.14). Likewise, 5-year cancer-specific survival did not significantly differ between groups on univariable Kaplan-Meier analysis (73% for ST and 74% for no ST, P = 0.7). Moreover, on multivariable analysis, receipt of ST was not significantly associated the risk of death from bladder cancer (HR 1.12; 95% CI 0.60-2.09, P = 0.7). Results were unchanged on sensitivity analysis.

CONCLUSIONS

These data suggest that, in carefully selected patients, ST following BCG for high grade NMIBC does not compromise oncologic outcomes for patients who ultimately undergo RC.

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.

Carcinoma in situ of the bladder: why is it underdetected?

PURPOSE OF REVIEW

The standard diagnosis of carcinoma in situ (CIS) of the bladder, based on white light cystoscopy and urine cytology, is limited because CIS can vary from normal-appearing mucosa to a lesion indistinguishable from an inflammatory process. Intravesical instillation of Bacillus Calmette-Guerin (BCG) remains first-line therapy; however, a significant proportion of cases persist or recur after BCG treatment. This review summarizes recent improvements in the detection and treatment of CIS.

RECENT FINDINGS

The new optical technologies improve CIS detection, with a potential positive impact on oncological outcomes. The usefulness of MRI-photodynamic diagnosis fusion transurethral resection in CIS detection is unclear and further studies are needed. BCG instillation remains the first-line therapy in CIS patients and seems to improve recurrence and progression rates, especially with the use of maintenance. Intravesical device-assisted therapies could be effective in both BCG-naïve and BCG-unresponsive CIS patients, but further studies are ongoing to clarify their clinical benefit. A phase II clinical trial with pembrolizumab has shown the potential effectiveness of immune checkpoint inhibitors in BCG-unresponsive CIS patients and further trials are ongoing.

SUMMARY

New optical techniques increase the CIS detection rate. BCG instillation remains the first-line treatment. Immune checkpoint inhibitors could be a future alternative in BCG-naïve and BCG-unresponsive CIS patients.

Midterm follow-up (3 years) confirms and extends short-term results of intravesical gemcitabine as bladder-preserving treatment for non-muscle-invasive bladder cancer after BCG failure

BACKGROUND

There is a high demand for bladder sparing therapies in patients who do not respond to bacillus Calmette-Guérin (BCG).

OBJECTIVE

To report the mid-term results of intravesical gemcitabine in non-muscle-invasive bladder cancer (NMIBC) patients, who failed BCG and who were unwilling to undergo radical cystectomy (RC).

MATERIAL & METHODS

This is an extended confirmatory open-label, single-arm study, which enrolled consecutive patients who failed BCG or were BCG intolerant and unwilling to undergo the RC (histologically confirmed Tis (CIS), T1 high grade or multifocal Ta high grade of the urinary bladder). Intravesical gemcitabine was administered once a week for 6 consecutive weeks and once a month for 12 months. The primary outcome was disease-free survival (DFS) defined as the lack of tumor on cystoscopy and negative urine cytology. The secondary endpoint was safety, defined according a grading of side effects. overall survival, progression-free survival and DFS were described with Kaplan-Meier method at 12, 24, and 36 months.

RESULTS AND LIMITATIONS

Overall 46 patients were enrolled. The mean follow-up was 40 months. The DFS was 69.05% at the end of induction phase and 32.69% at 36 months. The progression-free survival at 36 months was 65.38%. The overall survival and cancer specific survival were 66.97% (95% confidence interval 47.25%-80.70%) and 78.71% (95% confidence interval 59.16%-89.66%), respectively. There was no life-threatening event or treatment related death (grade 4 or 5). The most common mild and moderate adverse events reported were urinary symptoms (lower urinary tract symptoms) and fatigue (G1-G2).

CONCLUSION

Intravesical gemcitabine seemed to represent a valid and safe alternative at 3 years follow-up for patients who failed BCG and were unwilling to undergo RC.

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.

Intravesical gemcitabine as bladder‐preserving treatment for BCG unresponsive non‐muscle‐invasive bladder cancer. Results from a single‐arm, open‐label study

Background

There is an unmet alternative medical therapy for BCG unresponsive patients.

Objective

To report efficacy of intravesical gemcitabine in NMIBC patients, who failed a previous course of BCG, or intolerant, and unwilling to undergo radical cystectomy (RC).

Material and methods

This is an open‐label, single‐arm study, which enrolled patients showing a failure or were intolerant to BCG and unwilling to undergo the RC. Intravesical gemcitabine was administered once a week for six consecutive weeks and once a month for 12 months. The primary outcome was DFS defined as the lack of a tumor on cystoscopy and negative urine cytology. Secondary endpoint was safety defined according a grading of side effects. OS, PFS, and DFS were described with Kaplan–Meier method at 12 and 24 months.

Results and limitations

Overall 36 patients were enrolled. The median follow‐up was 27 months. The DFS was 68.75% at the end of induction phase and 44.44% and 31.66% at 12 and 24 months of, respectively. The PFS was 43.75%. The OS and CSS were 77.9% (95% CI 58.78%‐88.92%) and 80.68% (95% CI 61.49%‐90.96%), respectively. There was no life threatening event or treatment‐related death (grade 4 or 5). The most common mild and moderate adverse events reported were urinary symptoms (LUTS) and fatigue (G1‐G2).

Conclusion

Patients who presented an unresponsive‐BCG recurrent NMIBC and unwilling to receive a RC, could benefit from intravesical gemcitabine as salvage organ‐sparing treatment.

Antitumour Anthracyclines: Progress and Perspectives

Anthracyclines are ranked among the most effective chemotherapeutics against cancer. They are glycoside drugs comprising the amino sugar daunosamine linked to a hydroxy anthraquinone aglycone, and act by DNA intercalation, oxidative stress generation and topoisomerase II poisoning. Regardless of their therapeutic value, multidrug resistance and severe cardiotoxicity are important limitations of anthracycline treatment that have prompted the discovery of novel analogues. This review covers the most clinically relevant anthracyclines and their development over decades, since the first discovered natural prototypes to recent semisynthetic and synthetic derivatives. These include registered drugs, drug candidates undergoing clinical trials, and compounds under pre-clinical investigation. The impact of the structural modifications on antitumour activity, toxicity and resistance profile is addressed.

Evidence-based Assessment of Current and Emerging Bladder-sparing Therapies for Non-muscle-invasive Bladder Cancer After Bacillus Calmette-Guerin Therapy: A Systematic Review and Meta-analysis

CONTEXT

Currently, there is no standard of care for patients with non-muscle-invasive bladder cancer (NMIBC) who recur despite bacillus Calmette-Guerin (BCG) therapy. Although radical cystectomy is recommended, many patients decline to undergo or are ineligible to receive it. Multiple agents are being investigated for use in this patient population.

OBJECTIVE

To systematically synthesize and describe the efficacy and safety of current and emerging treatments for NMIBC patients after treatment with BCG.

EVIDENCE ACQUISITION

A systematic literature search of MEDLINE, Embase, and the Cochrane Controlled Register of Trials (period limited to January 2007-June 2019) was performed. Abstracts and presentations from major conference proceedings were also reviewed. Randomized controlled trials were assessed using the Cochrane risk of bias tool. Data for single-arm trials were pooled using a random-effect meta-analysis with the proportions approach. Trials were grouped based on the minimum number of prior BCG courses required before enrollment and further stratified based on the proportion of patients with carcinoma in situ (CIS).

EVIDENCE SYNTHESIS

Thirty publications were identified with data from 23 trials for meta-analysis, of which 17 were single arm. Efficacy and safety outcomes varied widely across studies. Heterogeneity across trials was reduced in subgroup analyses. The pooled 12-mo response rates were 24% (95% confidence interval [CI]: 16-32%) for trials with two or more prior BCG courses and 36% (95% CI: 25-47%) for those with one or more prior BCG courses. In a subgroup analysis, inclusion of ≥50% of patients with CIS was associated with a lower response.

CONCLUSIONS

The variability in efficacy and safety outcomes highlights the need for consistent endpoint reporting and patient population definitions. With promising emerging treatments currently in development, efficacious and safe therapeutic options are urgently needed for this difficult-to-treat patient population.

PATIENT SUMMARY

We examined the efficacy and safety outcomes of treatments for non-muscle-invasive bladder cancer after bacillus Calmette-Guerin therapy. Outcomes varied across studies and patient populations, but emerging treatments currently in development show promising efficacy.

Required efficacy for novel therapies in BCG-unresponsive non-muscle invasive bladder cancer: Do current recommendations really reflect clinically meaningful outcomes?

Background

Single‐arm trials are currently an accepted study design to investigate the efficacy of novel therapies (NT) in non‐muscle invasive bladder cancer (NMIBC) unresponsive to intravesical Bacillus Calmette‐Guérin (BCG) immunotherapy as randomized controlled trials are either unfeasible (comparator: early radical cystectomy; ERC), or unethical (comparator: placebo). To guide the design of such single‐arm trials, expert groups published recommendations for clinically meaningful outcomes. The aim of this study was to quantitatively verify the appropriateness of these recommendations.

Methods

We used a discrete event simulation framework in combination with a supercomputer to find the required efficacy at which a NT can compete with ERC when it comes to quality‐adjusted life expectancy (QALE). In total, 24 different efficacy thresholds (including the recommendations) were investigated.

Results

After ascertaining face validity with content experts, repeated verification, external validation, and calibration we considered our model valid. Both recommendations rarely showed an incremental benefit of the NT over ERC. In the most optimistic scenario, an increase in the IBCG recommendation by 10% and an increase in the FDA/AUA recommendation by 5% would yield results at which a NT could compete with ERC from a QALE perspective.

Conclusions

This simulation study demonstrated that the current recommendations regarding clinically meaningful outcomes for single‐arm trials evaluating the efficacy of NT in BCG‐unresponsive NMIBC may be too low. Based on our quantitative approach, we propose increasing these thresholds to at least 45%‐55% at 6 months and 35% at 18‐24 months (complete response rates/recurrence‐free survival) to promote the development of clinically truly meaningful NT.

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.

Intravesical Gene Therapy

Non-muscle-invasive bladder cancer is a challenging disease to treat, with few effective salvage intravesical options available for patients who develop bacillus Calmette-Guerin-unresponsive disease. Although radical cystectomy with pelvic lymphadenectomy remains the gold standard treatment for these patients, there remains an unmet need for other options for those who are unable or unwilling to undergo surgery. To this end, intravesical gene therapy is emerging as a potential alternative with promising early data and ongoing efforts to better understand the mechanisms of action to optimize therapy.

Bacillus Calmette-Guérin Salvage Therapy: Definitions and Context

High-risk non-muscle invasive bladder cancer is marked by frequent disease recurrences and risk of stage progression, contributing to high surveillance, treatment-related costs, and patient anxiety. Although the mainstay of high-risk non-muscle invasive bladder cancer clinical management remains transurethral resection followed by intravesical bacillus Calmette-Guérin (BCG), patients who develop BCG-unresponsive disease have few salvage options outside of a radical cystectomy with pelvic lymphadenectomy. This article provides a historical context relevant to the development of the BCG-unresponsive definition, an overview of current clinical trial expectations, and an introduction to this issue of Urologic Clinics.

Salvage Therapy Using Bacillus Calmette-Guérin Derivatives or Single Agent Chemotherapy

Despite therapy with intravesical Bacillus Calmette-Guérin, roughly 50% of patients with high-risk non-muscle-invasive bladder cancer will recur. Although cystectomy is the oncologic gold standard in BCG unresponsive disease, salvage intravesical therapies are valuable treatment options that aim to preserve quality of life while decreasing the risk of cancer recurrence and progression. Single-agent intravesical chemotherapy has been a mainstay salvage treatment and foundational to future trials of combination therapy. Treatment with Bacillus Calmette-Guérin derivative therapies has shown promise with response rates comparable with those of single agent chemotherapy and may warrant further investigation in the continued climate of Bacillus Calmette-Guérin shortages.