Intravesical Ad-IFNalpha causes marked regression of human bladder cancer growing orthotopically in nude mice and overcomes resistance to IFN-alpha protein

The Evolution of Nadofaragene Firadenovec: A Review and the Path Forward

BACKGROUND

The intravesical gene therapy nadofaragene firadenovec (rAd-IFNα/Syn3) was FDA approved in 2022 for non-muscle invasive bladder cancer (NMIBC) unresponsive to frontline treatment with BCG, and the first gene therapy developed for bladder cancer. This non-replicating recombinant adenovirus vector delivers a copy of the human interferon alpha-2b gene into urothelial and tumor cells, causing them to express this pleotropic cytokine with potent antitumor effects.

OBJECTIVE

To provide a historical overview describing how several decades of preclinical and clinical studies investigating the role of interferon in the treatment of bladder cancer ultimately led to the development of gene therapy with nadofaragene for NMIBC.

METHODS

We conducted a review of the literature using PubMed, Google Scholar, and ClinicalTrials.gov to summarize our knowledge of the evolution of interferon-based therapy in NMIBC.

RESULTS

The FDA approval of this therapy represents an important landmark in urologic oncology and several decades of research dedicated to the study of interferon's direct and indirect antitumor properties in NMIBC. The data gathered from the phase 1, 2, and 3 clinical trials continue to provide additional insights into the precise mechanisms underlying both the efficacy of and resistance to nadofaragene.

CONCLUSIONS

Nadofaragene leverages the cytotoxic, anti-angiogenic, and immune-modulatory roles of interferon to effectively treat NMIBC that is resistant to BCG. Ongoing studies of resistance mechanisms and prognostic biomarkers have been promising; these will ultimately improve patient selection and allow for the modulation of factors in the tumor or immune microenvironment to further increase therapeutic response.

An evaluation of nadofaragene firadenovec-vncg for the treatment of high-risk BCG-unresponsive non-muscle-invasive bladder cancer

INTRODUCTION

BCG-unresponsive non-muscle invasive bladder cancer (NMIBC) represent a significant therapeutic challenge in the treatment of bladder cancer. Nadofaragene firadenovec, represents a breakthrough in this area, offering a novel approach for the treatment of BCG-unresponsive NMIBC.

AREAS COVERED

This overview explores the historical development of nadofaragene firadenovec, assessing its efficacy and safety, and discusses future NMIBC therapy directions.

EXPERT OPINION

Patients with high grade NMIBC who are BCG unresponsive will have a growing number of treatment alternatives to bladder removal. Nadofaragene firadenovec offers good short-term efficacy but lacks significant durability for most patients. Its strengths include ease of administration and low risk of adverse events. This will need to balance with risk of progression and cost. Furthermore, the likely approval of other agents will require consideration of which therapy to use and for which patient. The need for biomarkers to tailor treatment choices to individual patient needs is becoming more critical. The treatment field is rapidly advancing, with several Phase 3 single-arm trials underway, indicating a potential broader range of treatment options for NMIBC. Further research will be necessary to determine the optimal choice for patients.

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.

Experimental and New Approaches for Bladder Preservation in Intermediate and High-Risk Non-Muscle-Invasive Bladder Cancer (NMIBC)

About 75% of bladder cancers are detected as non-muscle invasive. High-risk patients have high progression risk. Although the standard is transurethral resection of bladder tumor plus full dose intravesical BCG for one to 3 years, due to the high risk of progression, radical cystectomy may be considered in specific cases. Although radical cystectomy is still the best approach for high-grade NMIBC from an oncological perspective, its high morbidity and impact on quality of life motivate studies of new strategies that may reduce the need for cystectomy. We carried out a mini-review whose objectives were: 1 - to identify bladder-sparing alternatives that are being studied as possible treatment for patients with intermediate and high-risk NMIBC; 2 - understand the evidence that exists regarding success rate, follow-up, and side effects of different strategies. Several studies have sought alternatives for bladder preservation, including immunotherapy, intravesical chemotherapy, chemo-hyperthermia, antibody-drug conjugates, viral genetic therapy, and others with promising results. The selection of an optimal therapy for high-risk NMIBC that can reduce the need for cystectomy, with low toxicity and high efficacy, is of paramount importance and remains an issue, however, several known medications are being tested as bladder-preserving alternatives in this scenario and have shown promise in studies.

Mechanism of action of nadofaragene firadenovec-vncg

Effective bladder-preserving therapeutic options are needed for patients with bacillus Calmette-Guérin unresponsive non-muscle-invasive bladder cancer. Nadofaragene firadenovec-vncg (Adstiladrin®) was approved by the US Food and Drug Administration as the first gene therapy in urology and the first intravesical gene therapy indicated for the treatment of adult patients with high-risk bacillus Calmette-Guérin-unresponsive non-muscle-invasive bladder cancer with carcinoma in situ with or without papillary tumors. The proposed mechanism of action underlying nadofaragene firadenovec efficacy is likely due to the pleiotropic nature of interferon-α and its direct and indirect antitumor activities. Direct activities include cell death and the mediation of an antiangiogenic effect, and indirect activities are those initiated through immunomodulation of the innate and adaptive immune responses. The sustained expression of interferon-α that results from this treatment modality contributes to a durable response. This review provides insight into potential mechanisms of action underlying nadofaragene firadenovec efficacy.

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.

Targeting microRNA-145-mediated progressive phenotypes of early bladder cancer in a molecularly defined in vivo model

A progressive subclass of early-stage non-muscle-invasive bladder cancer (NMIBC) frequently recurs and progress into invasive carcinoma, thus decreasing the overall survival rate of NMIBC. However, therapeutic development for progressive NMIBC has been challenging due to the lack of molecularly validated in vivo models and agents targeting its genetic vulnerability. We herein molecularly characterized an interventional model of progressive NMIBC and revealed the principal functions and therapeutic potential of microRNA-145 (miR-145) in early bladder tumorigenesis. N-butyl-N-(4-hydroxybutyl)nitrosamine-induced premalignant lesions (BiPLs) in rats exhibited downregulated expression of miR-145 as well as highly similar mutation/expression profiles to those of the human progressive NMIBC subclass with the worst prognosis. The expression patterns of miR-145 inversely correlated with those of BC-related oncogenes in BiPLs. We also demonstrated that miR-145 dominantly regulated interferon pathways and c-Myc expression, which play a crucial role in the pathogenesis of progressive NMIBC. Furthermore, we demonstrated that miR-145 replacement with a novel miR-145-based intravesical agent (miR-145S1) significantly inhibited the progression of BiPLs in vivo. These results provide insights into the essential role of miR-145 as the earliest-acting oncogenic driver of bladder tumorigenesis as well as a validated interventional model and novel miR-145-based nucleic acid therapeutic agent for progressive NMIBC.

Interferon gene therapy with nadofaragene firadenovec for bladder cancer: from bench to approval

Bladder cancer is a prevalent malignancy with limited therapeutic options, particularly for patients who are unresponsive to Bacillus Calmette-Guérin (BCG). The approval of interferon-α (IFNα) gene therapy with nadofaragene firadenovec (Adstiladrin®), the first gene therapy for genitourinary malignancies, has provided a promising alternative. This article reviews the research and milestones that led to the development and approval of nadofaragene firadenovec. Bladder cancer is well-suited for gene therapy due to direct access to the bladder and the availability of urine and tissue samples for monitoring. Early challenges included effective gene transfer across the urothelium, which was overcome initially by modulating the expression of coxsackie/adenovirus receptor (CAR) and, ultimately, by disrupting the urothelial barrier with Syn3. Nadofaragene firadenovec is a modified adenoviral vector carrying the IFNα gene. Clinical trials have shown promising results, with high response rates and manageable adverse events. Ongoing research focuses on improving patient selection, identifying biomarkers for response prediction, exploring alternative vectors for enhanced transfection efficiency, and developing combination strategies targeting resistance mechanisms. The approval of nadofaragene firadenovec marks a significant milestone in the field of gene therapy for bladder cancer, and future developments hold promise for further enhancing its efficacy and impact.

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.

Adenoviral gene therapy for bladder cancer

Enhanced by polyamide surfactant Syn3, intravesical administration of rAd-IFNα2b results in transduction of the virus into the bladder epithelium, resulting in the synthesis and expression of local IFNα2b cytokine. Upon secretion, IFNα2b binds to the IFNα receptor on bladder cancer and other cells, resulting in signaling via the JAK-STAT pathway. A plethora of induced IFN-stimulated genes containing IFN-sensitive response elements that contribute to activation of pathways restrict cancer growth.

A Bayesian design for finding optimal biological dose with mixed types of responses of toxicity and efficacy

For molecularly targeted therapy and immunotherapy, the targeted dose in the early phase clinical trial has been shifted from the maximum tolerated dose for the cytotoxic drug to the optimal biological dose where both toxicity and efficacy are considered. In this paper, we consider the situation that the responses of toxicity and efficacy are mixed in binary and continuous types, respectively, where the continuous endpoint bears more magnitude information than the binary endpoint after dichotomization. We propose combining two model-based designs to sequentially identify the most efficacious and tolerably safe dose. The employed designs both take the dose level information into account to achieve high estimation efficiency. We demonstrate the superiority of the proposed method to some existing methods by simulation.

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.

Recurrence mechanisms of non-muscle-invasive bladder cancer - a clinical perspective

Non-muscle-invasive bladder cancer (NMIBC) is an early-stage cancer without invasion into the detrusor muscle layer. Transurethral resection of bladder tumour (TURBT) is a diagnostic and potentially curative procedure for NMIBC, but has some limitations, including difficulties in ascertaining complete tumour removal upon piecemeal resection and the possibility of tumour re-implantation after the procedure. The oncological control of NMIBC is far from satisfactory, with a 1-year recurrence rate of 15-61%, and a 5-year recurrence rate of 31-78%. Various recurrence mechanisms have been described for NMIBC, such as undetected tumours upon cystoscopy, incomplete resection during TURBT, tumour re-implantation after TURBT, drop metastasis from upper tract urothelial carcinoma and field change cancerization. Understanding the recurrence mechanisms from a clinical perspective has strong implications for the optimization of NMIBC oncological outcomes, as a cure for patients with NMIBC can only be achieved by tackling all possible recurrence mechanisms in a comprehensive manner.

Evolution of immunotherapy in the treatment of non-muscle-invasive bladder cancer

INTRODUCTION

Immunotherapy with intravesical bacillus Calmette-Guérin (BCG) has been the gold standard treatment for intermediate- and high-risk non-muscle-invasive bladder cancer (NMIBC) for nearly half a century. Yet, many patients with high-risk disease will experience recurrence, including those who progress and eventually become unresponsive to BCG. For decades, apart from radical cystectomy, few therapeutic options existed for this at-risk population. However, the advent of novel immunotherapeutic agents has transformed treatment in a range of tumour types, including urothelial carcinoma. These immunotherapies have yielded promising results in the treatment of metastatic urothelial carcinoma and, as such, are also being investigated for use in NIMIBC.

AREAS COVERED

This article provides an overview of the evolution of immunotherapy for NMIBC, beginning from the original immunotherapy- BCG - to current agents including checkpoint inhibitors, IL-15 agonists, viral gene therapies and therapeutic cancer vaccines.

EXPERT OPINION

The KEYNOTE-057 trial represented a pivotal moment for immunotherapy in NMIBC, but patient selection and the development of biomarkers to guide the identification of patients who will benefit most from a particular immunotherapy remains critical. As research efforts come to fruition, novel immunotherapies may become integrated into the standard treatment paradigm for intermediate- and high-risk NMBIC.

Molecular characterization of type I IFN-induced cytotoxicity in bladder cancer cells reveals biomarkers of resistance

Although anti-tumor activities of type I interferons (IFNs) have been recognized for decades, the molecular mechanisms contributing to clinical response remain poorly understood. The complex functions of these pleiotropic cytokines include stimulation of innate and adaptive immune responses against tumors as well as direct inhibition of tumor cells. In high-grade, Bacillus Calmette-Guérin (BCG)-unresponsive non-muscle-invasive bladder cancer, nadofaragene firadenovec, a non-replicating adenovirus administered locally to express the IFNα2b transgene, embodies a novel approach to deploy the therapeutic activity of type I IFNs while minimizing systemic toxicities. Deciphering which functions of type I IFN are required for clinical activity will bolster efforts to maximize the efficacy of nadofaragene firadenovec and other type I IFN-based therapies, and inform strategies to address resistance. As such, we characterized the phenotypic and molecular response of human bladder cancer cell lines to IFNα delivered in multiple contexts, including adenoviral delivery. We found that constitutive activation of the type I IFN signaling pathway is a biomarker for resistance to both transcriptional response and direct cytotoxic effects of IFNα. We present several genes that discriminate between sensitive and resistant tumor cells, suggesting they should be explored for utility as biomarkers in future clinical trials of type I IFN-based anti-tumor therapies.

Immunotherapy for non-muscle-invasive bladder cancer: from the origins of BCG to novel therapies

Supplies of intravesical Bacillus Calmette-Guérin (BCG), the first-line treatment for most intermediate- and high-risk non-muscle-invasive bladder cancers (NMIBC), have proven unreliable over the past decade. This review considers the evolution of BCG immunotherapy for NMIBC: from the discovery of the antitumour side effects of tuberculosis and subsequently the BCG vaccine, to recent advances in novel immunotherapeutic agents. We summarize the evidence for alternative options to standard intravesical BCG therapy regimens and describe the potential for immune response manipulating drugs in the treatment of NMIBC. These new agents, including immune checkpoint inhibitors, toll-like receptor agonists and recombinant viral vectors, may provide better options in the management of NMIBC in the future.

Emerging roles of autophagy in the development and treatment of urothelial carcinoma of the bladder

INTRODUCTION

High recurrence rates, frequent surveillance strategies, and current multidisciplinary treatment approaches make urothelial carcinoma of bladder (UCB) one of the most expensive cancers to clinically manage. Recent studies have demonstrated a role for autophagy in bladder tumorigenesis. It serves as a tumor suppressor by maintaining genomic integrity and preventing tumor proliferation during initial stages of tumor development. Nevertheless, once established, cancer cells may utilize protective autophagy to endure cellular stress and survive in the adverse environment. Its excessive stimulation supports cancer cells' resistance to therapeutic modalities.

AREAS COVERED

PubMed and Google Scholar electronic databases were searched for recently published studies. This review summarizes emerging roles of autophagy in development/progression of UCB and treatment resistance and explores novel therapeutic targets for prevention of cancer invasion, metastatic spread', and disease relapse.

EXPERT OPINION

The development of novel therapies via targeting of autophagy may augment current treatment regimens and improve clinical outcomes. Synthetic compounds or plant-based metabolites are reported to enhance cancer therapies by modulating autophagic flux. Successful autophagy-focused therapeutic intervention requires a mechanistic understanding of autophagic effects on tumor initiation and progression and the development of efficient biomarkers to monitor it in tumor tissues.

Immunotherapy of high risk non-muscle invasive bladder cancer

INTRODUCTION

Bladder cancer remains a prevalent and often lethal cancer. Fortunately, recent clinical trials using immunotherapeutics demonstrate promise to improve treatment outcomes. Several of these immunotherapies have already established their value in the metastatic space and likely will soon have indications in the non-metastatic space.

AREAS COVERED

This review will cover immunotherapies ranging for well-studied BCG administration to more novel medications such as PD-L1/PD-1 inhibitors, CTLA-4 inhibitors, IL-15 super agonists, and immune modulating gene therapies. Specifically, the article will address the mechanisms of actions, clinical evidence supporting their use, and the presence of any FDA regulatory approval for these medications in the treatment of high-risk non-muscle invasive bladder cancer.

EXPERT OPINION

With the publication of clinical data supporting the use of immunotherapies, these novel medications are likely to be adopted for treatment of high grade non-metastatic bladder cancer. While BCG is likely to remain a primary medication for high grade bladder cancer for the near future, BCG will likely be co-administered with immunomodulatory medications in some patients to enhance the medications effect in the future. Clinical trials are still ongoing and will demonstrate which of these multiple treatment options yield results worthy of a modification in our current treatment paradigm.

The effectiveness and value of nadofaragene firadenovec, oportuzumab monatox, and pembrolizumab for BCG-unresponsive non-muscle-invasive bladder cancer

DISCLOSURES: Funding for this summary was contributed by Arnold Ventures, California Health Care Foundation, The Donaghue Foundation, Harvard Pilgrim Health Care, and Kaiser Foundation Health Plan to the Institute for Clinical and Economic Review (ICER), an independent organization that evaluates the evidence on the value of health care interventions. ICER's annual policy summit is supported by dues from AbbVie, Aetna, America's Health Insurance Plans, Anthem, Alnylam, AstraZeneca, Biogen, Blue Shield of CA, Boehringer-Ingelheim, Cambia Health Services, CVS, Editas, Evolve Pharmacy, Express Scripts, Genentech/Roche, GlaxoSmithKline, Harvard Pilgrim, Health Care Service Corporation, HealthFirst, Health Partners, Humana, Johnson & Johnson (Janssen), Kaiser Permanente, LEO Pharma, Mallinckrodt, Merck, Novartis, National Pharmaceutical Council, Pfizer, Premera, Prime Therapeutics, Regeneron, Sanofi, Spark Therapeutics, uniQure, and United Healthcare. Beinfeld, McKenna, Rind, and Pearson are employed by ICER. Touchette received funding from ICER for work on this report and has also received fees from Monument Analytics and AstraZeneca, unrelated to this work. The University of Illinois at Chicago (UIC) and Touchette hold a patent for the model described in this report. The model is included in ICER's Interactive Modeler, for which a fee is paid to UIC and Touchette. Atlas also received funding from ICER for work on this report.

Treating Bladder Cancer: Engineering of Current and Next Generation Antibody-, Fusion Protein-, mRNA-, Cell- and Viral-Based Therapeutics

Bladder cancer is a frequent malignancy and has a clinical need for new therapeutic approaches. Antibody and protein technologies came a long way in recent years and new engineering approaches were applied to generate innovative therapeutic entities with novel mechanisms of action. Furthermore, mRNA-based pharmaceuticals recently reached the market and CAR-T cells and viral-based gene therapy remain a major focus of biomedical research. This review focuses on the engineering of biologics, particularly therapeutic antibodies and their application in preclinical development and clinical trials, as well as approved monoclonal antibodies for the treatment of bladder cancer. Besides, newly emerging entities in the realm of bladder cancer like mRNA, gene therapy or cell-based therapeutics are discussed and evaluated. As many discussed molecules exhibit unique mechanisms of action based on innovative protein engineering, they reflect the next generation of cancer drugs. This review will shed light on the engineering strategies applied to develop these next generation treatments and provides deeper insights into their preclinical profiles, clinical stages, and ongoing trials. Furthermore, the distribution and expression of the targeted antigens and the intended mechanisms of action are elucidated.

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.

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.

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.

Distinct Roles of Direct Transduction Versus Exposure to the Tumor Secretome on Murine Endothelial Cells After Melanoma Gene Therapy with Interferon-β and p19Arf

Tumor vasculature plays a central role in tumor progression, making it an attractive therapeutic target. In this study, we explore the antiangiogenic potential of our melanoma gene therapy approach combining interferon β (IFNβ) and p19Arf gene transfer. Since these proteins are modulators of tumor vasculature, we explore the impact of IFNβ and p19Arf gene transfer on murine endothelial cells (tEnd). Adenovirus-mediated gene transfer of p19Arf to tEnd cells inhibited proliferation, tube formation, migration, and led to increased expression of genes related to the p53 cell death pathway, yet IFNβ gene transfer had no significant impact on tEnd viability. Alternatively, tEnd cells were exposed to the factors generated by transduced B16 (mouse melanoma) cells using either coculture or conditioned medium. In either case, transduction of B16 cells with the IFNβ vector, whether alone or in combination with p19Arf, resulted in endothelial cell death. Strikingly, treatment of tEnd cells with recombinant IFNβ did not induce death, demonstrating that additional factors produced by B16 cells contributed to the demise of tEnd cells. In this work, we have shown that our melanoma gene therapy strategy produces desirable negative effects on endothelial cells, possibly correlating with antiangiogenic activity.

Inhibition of urothelial carcinoma through targeted type I interferon-mediated immune activation

Type I interferon (IFN-I) has potent anti-tumor effects against urothelial carcinoma (UC) and may be an alternative treatment option for patients who do not respond to Bacillus Calmette-Guerin. However, the mechanisms that mediate the IFN-I-stimulated immune responses against UC have yet to be elucidated. Herein, we evaluated the anti-tumor mechanisms of IFN-I in UC in human patients and in mice. Patient tumors from a Phase I clinical trial with adenoviral interferon-α (Ad-IFNα/Syn3) showed increased expression of T cell and checkpoint markers following treatment with Ad-IFNα/Syn3 by RNAseq and immunohistochemistry analysis in 25% of patients. In mice, peritumoral injections of poly(I:C) into MB49 UC tumors was used to incite an IFN-driven inflammatory response that significantly inhibited tumor growth. IFN-I engaged both innate and adaptive cells, seen in increased intratumoral CD8 T cells, NK cells, and CD11b+Ly6G+ cells, but tumor inhibition was not reliant on any one immune cell type. Nonetheless, poly(I:C)-mediated tumor regression and change in the myeloid cell landscape was dependent on IL-6. Mice were also treated with poly(I:C) in combination with anti-PD-1 monoclonal antibody (mAb) to assess for additional benefit to tumor growth and animal survival. When used in combination with anti-PD-1 mAb, IFN-I stimulation prolonged survival, coinciding with inhibition of angiogenesis and enriched gene signatures of metabolism, extracellular matrix organization, and MAPK/AKT signaling. Altogether, these findings suggest IFN-I's immune-driven antitumor response in UC is mediated by IL-6 and a collaboration of immune cells, and its use in combination with checkpoint blockade therapy can increase clinical benefit.

The development of interferon-based gene therapy for BCG unresponsive bladder cancer: from bench to bedside

BACKGROUND AND PURPOSE

BCG unresponsive bladder cancer is an inherently resistant disease state for which the preferred treatment is radical cystectomy. To date, no effective intravesical therapies exist for patients who possess these resistant tumors. For this reason, many research groups are actively investigating/testing novel therapeutic agents to aid in bladder preservation for this patient population. This review article describes our 15-year experience developing and testing IFN-based gene therapy.

METHODS

A comprehensive review was performed of all studies pertaining to IFN-based gene therapy for non-muscle invasive bladder cancer from 2003 to 2018.

RESULTS AND CONCLUSIONS

Over the past two decades, gene therapy has evolved into a powerful tool in our fight against cancer. After overcoming the initial barriers associated with gene delivery to the bladder, we have made significant strides forward in developing this novel therapeutic strategy for the treatment of this inherently resistant disease state. Our results to date are very encouraging; however, much work lies ahead to better understand and optimize this novel approach for treating non-muscle invasive bladder.

Electrostatic interaction of tumor-targeting adenoviruses with aminoclay acquires enhanced infectivity to tumor cells inside the bladder and has better cytotoxic activity

In a previous report, 3-aminopropyl functionalized magnesium phyllosilicate (aminoclay) improved adenovirus transduction efficiency by shielding the negative surface charges of adenovirus particles. The present study analyzed the physicochemical characterization of the electrostatic complex of adenoviruses with aminoclay and explored whether it could be utilized for enhancing tumor suppressive activity in the bladder. As a result of aminoclay-adenovirus nanobiohybridization, its transduction was enhanced in a dose-dependent manner, increasing transgene expression in bladder cancer cells and in in vivo animal models. Physicochemical studies demonstrated that positively charged aminoclay led to the neutralization of negative surface charges of adenoviruses, protection of adenoviruses from neutralizing antibodies and lowered transepithelial electrical resistance (TEER). As expected from the physicochemical properties, the aminoclay enabled tumor-targeting adenoviruses to be more potent in killing bladder cancer cells and suppressing tumor growth in orthotopic bladder tumors, suggesting that aminoclay would be an efficient, versatile and biocompatible delivery carrier for intravesical instillation of adenoviruses.

Intravesical rAd-IFNα/Syn3 for Patients With High-Grade, Bacillus Calmette-Guerin-Refractory or Relapsed Non-Muscle-Invasive Bladder Cancer: A Phase II Randomized Study

Purpose Many patients with high-risk non-muscle-invasive bladder cancer (NMIBC) are either refractory to bacillus Calmette-Guerin (BCG) treatment or may experience disease relapse. We assessed the efficacy and safety of recombinant adenovirus interferon alfa with Syn3 (rAd-IFNα/Syn3), a replication-deficient recombinant adenovirus gene transfer vector, for patients with high-grade (HG) BCG-refractory or relapsed NMIBC. Methods In this open-label, multicenter (n = 13), parallel-arm, phase II study ( ClinicalTrials.gov identifier: NCT01687244), 43 patients with HG BCG-refractory or relapsed NMIBC received intravesical rAd-IFNα/Syn3 (randomly assigned 1:1 to 1 × 10¹¹ viral particles (vp)/mL or 3 × 10¹¹ vp/mL). Patients who responded at months 3, 6, and 9 were retreated at months 4, 7, and 10. The primary end point was 12-month HG recurrence-free survival (RFS). All patients who received at least one dose were included in efficacy and safety analyses. Results Forty patients received rAd-IFNα/Syn3 (1 × 10¹¹ vp/mL, n = 21; 3 × 10¹¹ vp/mL, n = 19) between November 5, 2012, and April 8, 2015. Fourteen patients (35.0%; 90% CI, 22.6% to 49.2%) remained free of HG recurrence 12 months after initial treatment. Comparable 12-month HG RFS was noted for both doses. Of these 14 patients, two experienced recurrence at 21 and 28 months, respectively, after treatment initiation, and one died as a result of an upper tract tumor at 17 months without a recurrence. rAd-IFNα/Syn3 was well tolerated; no grade four or five adverse events (AEs) occurred, and no patient discontinued treatment because of an adverse event. The most frequently reported drug-related AEs were micturition urgency (n = 16; 40%), dysuria (n = 16; 40%), fatigue (n = 13; 32.5%), pollakiuria (n = 11; 28%), and hematuria and nocturia (n = 10 each; 25%). Conclusion rAd-IFNα/Syn3 was well tolerated. It demonstrated promising efficacy for patients with HG NMIBC after BCG therapy who were unable or unwilling to undergo radical cystectomy.

Showing the Way: Oncolytic Adenoviruses as Chaperones of Immunostimulatory Adjuncts

Oncolytic adenoviruses (OAds) are increasingly recognized as vectors for immunotherapy in the treatment of various solid tumors. The myriads of advantages of using adenovirus include targeted specificity upon infection and selective replication, which lead to localized viral burst, exponential spread of OAds, and antitumor effect. OAds can also induce a strong immune reaction due to the massive release of tumor antigens upon cytolysis and the presence of viral antigens. This review will highlight recent advances in adenoviral vectors expressing immunostimulatory effectors, such as GM-CSF (granulocyte macrophage colony-stimulating factor), interferon-α, interleukin-12, and CD40L. We will also discuss the combination of OAds with other immunotherapeutic strategies and describe the current understanding of how adenoviral vectors interact with the immune system to eliminate cancer cells.

Phase 1b Trial to Evaluate Tissue Response to a Second Dose of Intravesical Recombinant Adenoviral Interferon α2b Formulated in Syn3 for Failures of Bacillus Calmette-Guerin (BCG) Therapy in Nonmuscle Invasive Bladder Cancer

BACKGROUND

A phase 1b trial was conducted to evaluate the duration of interferon-alpha (IFNα) production after intravesical administration of recombinant adenovirus-mediated interferon α2b (Ad-IFN) formulated with the excipient Syn3. The primary aim was to determine whether a second instillation 3 days after initial treatment produced prolonged urinary IFN production.

METHODS

The study enrolled seven patients who experienced recurrent non-muscle invasive bladder cancer after bacillus Calmette-Guerin therapy. Each treatment consisted of intravesical instillation of SCH721015 (Syn3) and Ad-IFN at a concentration of 3 × 10¹¹ particles/mL to a total volume of 75 mL given on days 1 and 4. The patients were followed for 12 weeks, during which the magnitude and duration of gene transfer were determined by urine INFα levels. Drug efficacy was determined by cystoscopy and biopsy, and patients who had no recurrence at 12 weeks were eligible for a second course of treatment.

RESULTS

Seven patients were treated with an initial course (instillation on days 1 and 4). Two of the patients had a complete response at 12 weeks and received a second course of treatment. One patient remained without evidence of recurrence after a second course (total 24 weeks). One patient experienced a non-treatment-associated adverse event. Despite a transient rise in IFNα levels, sustained production was not demonstrated.

CONCLUSION

Previously, Ad-IFNα intravesical therapy has shown promising drug efficacy. A prior phase 1 trial with a single instillation compared similarly with the current study, suggesting that a second instillation is not necessary to achieve sufficient urinary IFNα levels.

Autophagy and urothelial carcinoma of the bladder: A review

The incidence of urothelial carcinoma of the urinary bladder (bladder cancer) remains high. While other solid organ malignancies have seen significant improvement in morbidity and mortality, there has been little change in bladder cancer mortality in the past few decades. The mortality is mainly driven by muscle invasive bladder cancer, but the cancer burden remains high even in nonmuscle invasive bladder cancer due to high recurrence rates and risk of progression. While apoptosis deregulation has long been an established pathway for cancer progression, nonapoptotic pathways have gained prominence of late. Recent research in the role of autophagy in other malignancies, including its role in treatment resistance, has led to greater interest in the role of autophagy in bladder cancer. Herein, we summarize the literature regarding the role of autophagy in bladder cancer progression and treatment resistance. We address it by systematically reviewing treatment modalities for nonmuscle invasive and muscle invasive bladder cancer.

A Multimodal Imaging Approach for Longitudinal Evaluation of Bladder Tumor Development in an Orthotopic Murine Model

Bladder cancer is the fourth most common malignancy amongst men in Western industrialized countries with an initial response rate of 70% for the non-muscle invasive type, and improving therapy efficacy is highly needed. For this, an appropriate, reliable animal model is essential to gain insight into mechanisms of tumor growth for use in response monitoring of (new) agents. Several animal models have been described in previous studies, but so far success has been hampered due to the absence of imaging methods to follow tumor growth non-invasively over time. Recent developments of multimodal imaging methods for use in animal research have substantially strengthened these options of in vivo visualization of tumor growth. In the present study, a multimodal imaging approach was addressed to investigate bladder tumor proliferation longitudinally. The complementary abilities of Bioluminescence, High Resolution Ultrasound and Photo-acoustic Imaging permit a better understanding of bladder tumor development. Hybrid imaging modalities allow the integration of individual strengths to enable sensitive and improved quantification and understanding of tumor biology, and ultimately, can aid in the discovery and development of new therapeutics.

Management of carcinoma in situ of the bladder: best practice and recent developments

Management of carcinoma in situ of the bladder remains a complex and challenging endeavor due to its high rate of recurrence and progression. Although it is typically grouped with other nonmuscle invasive bladder cancers, its higher grade and aggressiveness make it a unique clinical entity. Intravesical bacillus Calmette-Guérin is the standard first-line treatment given its superiority to other agents. However, high rates of bacillus Calmette-Guérin failure highlight the need for additional therapies. Radical cystectomy has traditional been the standard second-line therapy, but additional intravesical therapies may be more appealing for non-surgical candidates and patients refusing cystectomy. The subject of this review is the treatment strategies and available therapies currently available for carcinoma in situ of the bladder. It discusses alternative intravesical treatment options for patients whose condition has failed to respond to bacillus Calmette-Guérin therapy and who are unfit or unwilling to undergo cystectomy.

Interferon-β gene transfer inhibits melanoma cells adhesion and migration

We evaluated the effects of expression of interferon-β (IFNβ) after lipofection on melanoma cells adhesion and migration. Three canine mucosal (Ak, Br and Ol) and one human dermal (SB2) melanomas were assayed. By means of the wound healing assay, we found a significant inhibitory effect of canine IFNβ gene expression on cells migration in Br and Ol monolayers. This effect could be reproduced on unlipofected Ol cells with conditioned culture media obtained from canine IFNβ gene-lipofected Ol cells, and with recombinant human IFNβ on unlipofected SB2 cells. Furthermore, IFNβ gene expression of the four tested tumor cells significantly inhibited their adhesion to extracellular matrix (ECM) proteins and their spreading from multicellular spheroids onto gelatin coating. The addition of catalase reverted the increase of reactive oxygen species (ROS) in Ol cells and the inhibition of cell migration in monolayers (Ol) and spheroids (Ol an SB2) produced by canine and human IFNβ expression, suggesting the involvement of ROS as mediators of IFNβ action on the cells interactions with ECM. Together with its known immune, antiangiogenic and cytotoxic effects, the present data strongly support more studies exploring the clinical potential of IFNβ for cancer therapy.

Interferon-β gene transfer induces a strong cytotoxic bystander effect on melanoma cells

A local gene therapy scheme for the delivery of type I interferons could be an alternative for the treatment of melanoma. We evaluated the cytotoxic effects of interferon-β (IFNβ) gene lipofection on tumor cell lines derived from three human cutaneous and four canine mucosal melanomas. The cytotoxicity of human IFNβ gene lipofection resulted higher or equivalent to that of the corresponding addition of the recombinant protein (rhIFNβ) to human cells. IFNβ gene lipofection was not cytotoxic for only one canine melanoma cell line. When cultured as monolayers, three human and three canine IFNβ-lipofected melanoma cell lines displayed a remarkable bystander effect. As spheroids, the same six cell lines were sensitive to IFNβ gene transfer, two displaying a significant multicell resistance phenotype. The effects of conditioned IFNβ-lipofected canine melanoma cell culture media suggested the release of at least one soluble thermolabile cytotoxic factor that could not be detected in human melanoma cells. By using a secretion signal-free truncated human IFNβ, we showed that its intracellular expression was enough to induce cytotoxicity in two human melanoma cell lines. The lower cytoplasmatic levels of reactive oxygen species detected after intracellular IFNβ expression could be related to the resistance displayed by one human melanoma cell line. As IFNβ gene transfer was effective against most of the assayed melanomas in a way not limited by relatively low lipofection efficiencies, the clinical potential of this approach is strongly supported.

Novel therapeutic approaches for recurrent nonmuscle invasive bladder cancer

This article summarizes strategies being investigated in patients with nonmuscle invasive bladder cancer. Progress has been made toward improving the delivery method of intravesical agents. Intravesical therapy is limited by the amount of time that the agent remains in contact with the bladder. Bladder cancer is considered to be responsive to immune therapy. Thus, many novel approaches are immune-based therapies and include cancer vaccines, use of Bacillus Calmette-Guérin (BCG) subcomponents, and checkpoint inhibitors. Finally, access to bladder mucosa via direct catheterization into the bladder via the urethra has enabled unique strategies for delivery of cancer therapy including viral- or plasmid-based gene therapy.

Oncolytic adenovirus expressing interferon alpha in a syngeneic Syrian hamster model for the treatment of pancreatic cancer

BACKGROUND

The addition of interferon (IFN) alpha to adjuvant chemoradiotherapy regimens resulted in remarkable improvements in survival for pancreatic cancer patients. However, systemic toxicities and insufficient levels of IFN at the tumor sites have limited its widespread adoption in treatment schemes. We have previously developed an IFN-expressing conditionally replicative oncolytic adenovirus and demonstrated its therapeutic effects both in vitro and in vivo. Here, the same vectors were tested in a syngeneic and immunocompetent Syrian hamster model to better understand the roles of adenoviral replication and of the pleiotropic effects of IFN on pancreatic tumor growth suppression.

METHODS

Oncolytic adenoviruses expressing human or hamster IFN were designed and generated. Viral vectors were tested in vitro to determine qualitative and quantitative cell viability, cyclooxygenase 2 (Cox2) promoter activity, and IFN production. For the in vivo studies, subcutaneous hamster pancreatic cancer tumors were treated with 1 intratumoral dose of virus. Similarly, 1 intraperitoneal dose of virus was used to prolong survival in a carcinomatosis model.

RESULTS

All cell lines tested demonstrated Cox2 promoter activity. The oncolytic potential of a replication competent adenovirus expressing the IFN cytokine was clearly demonstrated. These viruses resulted in significant tumor growth suppression and survival increases compared with controls in a hamster model.

CONCLUSION

The profound therapeutic potential of an IFN-expressing oncolytic adenovirus for the treatment of pancreatic cancer was demonstrated in a syngeneic Syrian hamster model. These results strongly suggest the potential application of our viruses as part of combination regimens with other therapeutics.

Use of monitoring levels of soluble forms of cytokeratin 18 in the urine of patients with superficial bladder cancer following intravesical Ad-IFNα/Syn3 treatment in a phase l study

A phase l study using intravesical Ad-IFNα/Syn3 for patients with BCG resistant superficial bladder cancer showed a complete remission (CR) of 43% at 90 days after treatment with high levels of IFNα being produced. Ad-IFNα kills bladder cancer cells by two apoptotic and one necrotic mechanism that can be measured by soluble forms of cytokeratin 18 (CK 18) using M30 and M65 ELISAs, assays for caspase –cleaved (apoptotic) and uncleaved (necrotic) cell death, respectively. Therefore we determined whether M30 and M65 levels in the urine after treatment could document all three mechanisms of cancer cell kill and also predict having a CR. High levels of both M30 and M65 were found in all patients within 24 hours after treatment with all three types of cancer cell death occuring. Moreover, the return of both M30 and M65 levels in the urine to normal levels within 5 days or more after treatment was strongly associated with obtaining a CR (p=0.003). This is the first time that such assays have been used to study response to therapy in the urine of patients with bladder cancer and in the future may prove valuable in predicting clinical outcome.

Phase I trial of intravesical recombinant adenovirus mediated interferon-α2b formulated in Syn3 for Bacillus Calmette-Guérin failures in nonmuscle invasive bladder cancer

PURPOSE

A phase I trial of intravesical recombinant adenovirus mediated interferon-α2b gene therapy (rAd-IFNα) formulated with the excipient SCH Syn3 was conducted in patients with nonmuscle invasive bladder cancer who had disease recurrence after treatment with bacillus Calmette-Guérin. The primary objective was to determine the safety of rAd-IFNα/Syn3. Secondary end points were demonstrated effective rAd-IFNα gene expression and preliminary evidence of clinical activity at 3 months.

MATERIALS AND METHODS

A total of 17 patients with recurrent nonmuscle invasive bladder cancer after bacillus Calmette-Guérin treatment were enrolled in the study. A single treatment of rAd-IFNα (3 × 10(9) to 3 × 10(11) particles per ml) formulated with the excipient Syn3 was administered. Patient safety was evaluated for 12 or more weeks. Efficacy of gene transfer was determined by urine IFNα protein concentrations. Preliminary drug efficacy was determined at 3 months.

RESULTS

Intravesical rAd-IFNα/Syn3 was well tolerated as no dose limiting toxicity was encountered. Urgency was the most common adverse event and all cases were grade 1 or 2. rAd-IFNα DNA was not detected in the blood. However, transient low serum IFNα and Syn3 levels were measured. High and prolonged dose related urine IFNα levels were achieved with the initial treatment. Of the 14 patients treated at doses of 10(10) or more particles per ml with detectable urine IFNα, 6 (43%) experienced a complete response at 3 months and 2 remained disease-free at 29.0 and 39.2 months, respectively.

CONCLUSIONS

Intravesical rAd-IFNα/Syn3 was well tolerated with no dose limiting toxicity encountered. Dose dependent urinary IFNα concentrations confirmed efficient gene transfer and expression. Intravesical rAd-IFNα/Syn3 demonstrated clinical activity in nonmuscle invasive bladder cancer recurring after bacillus Calmette-Guérin.

Hiding in plain view: genetic profiling reveals decades old cross contamination of bladder cancer cell line KU7 with HeLa

PURPOSE

KU7 is a popular urothelial carcinoma cell line that was isolated from the bladder of a patient at Keio University in 1980. It has subsequently been widely used in laboratories around the world. We describe how routine cell line authentication revealed that KU7 was cross contaminated almost 30 years ago with HeLa, a cervical carcinoma cell line.

MATERIALS AND METHODS

Presumed KU7 clones dating from 1984 to 1999 were provided by M.D. Anderson Cancer Center, Vancouver Prostate Centre, Kyoto University, Tokyo Medical University and Keio University. HeLa was obtained from ATCC. Genomic DNA was isolated and short tandem repeat analysis was performed at the M.D. Anderson Cancer Center Characterized Cell Line Core Facility, Johns Hopkins University Fragment Analysis Facility and RIKEN BioResource Center, Ibaraki, Japan. Comparative genomic hybridization was performed on a platform (Agilent Technologies, Santa Clara, California) at Vancouver Prostate Centre.

RESULTS

The short tandem repeat profile of all KU7 clones was an exact match with that of HeLa. Comparative genomic hybridization of all samples revealed an abundance of shared chromosomal aberrations. Slight differences in some genomic areas were explained by genomic drift in different KU7 clones separated by many years.

CONCLUSIONS

Our analysis identified that cross contamination of KU7 with HeLa occurred before 1984 at the source institution. All KU7 clones in the urological literature should be considered HeLa and experimental results should be viewed in this light. Our results emphasize the need to authenticate cell lines in oncological research.

PMN and anti-tumor immunity--the case of bladder cancer immunotherapy

Urothelial carcinoma of the bladder accounts for ∼5% of all cancer deaths in humans. The majority of bladder tumors are non-muscle invasive at diagnosis, and there is a high rate of tumor recurrence and progression even after local surgical therapy. Thus, many patients require lifelong follow-up examinations that include additional prophylactic treatments in the event of recurrence. Since its first use in 1976, Mycobacterium bovis bacillus Calmette-Guerin (BCG) has been the treatment of choice for non-muscle invasive bladder cancer. Despite nearly 40 years of clinical use, the mechanism(s) by which intravesical administration of BCG results in elimination of bladder tumors remains undefined. Granulocytes (polymorphonuclear neutrophils (PMN)) are the predominant immune cell (in number) that enters the bladder after BCG installation, and a number of studies have highlighted the importance of PMN in the antitumor activity of BCG. Studies from our laboratory demonstrated presence of intracellular stores of the apoptosis-inducing protein TNF-related apoptosis-inducing ligand (TRAIL) in PMN that are rapidly released after interaction with BCG cell wall components, along with a correlation between increased urinary levels of TRAIL and BCG responsiveness. Mature PMN in circulation are terminally differentiated cells with limited biosynthetic capacity, so the proteins located in the distinct PMN granule populations are compartmentalized concomitant with their synthesis during myelopoiesis. Thus, understanding PMN production, localization, and release of TRAIL is important in the design of future BCG-based bladder tumor immunotherapy protocols.

Syngeneic hematopoietic stem cell transplantation enhances the antitumor immunity of intratumoral type I interferon gene transfer for sarcoma

Sarcoma at advanced stages remains a clinically challenging disease. Interferons (IFNs) can target cancer cells by multiple antitumor activities, including the induction of cancer cell death and enhancement of immune response. However, the development of an effective cancer immunotherapy is often difficult, because cancer generates an immunotolerant microenvironment against the host immune system. An autologous hematopoietic stem cell transplantation (HSCT) is expected to reconstitute a fresh immune system, and expand tumor-specific T cells through the process of homeostatic proliferation. Here we examined whether a combination of autologous HSCT and IFNs could induce an effective tumor-specific immune response against sarcoma. First, we found that a type I IFN gene transfer significantly suppressed the cell growth of various sarcoma cell lines, and that IFN-β gene transfer was more effective in inducing cell death than was IFN-α in sarcoma cells. Then, to examine the antitumor effect in vivo, human sarcoma cells were inoculated in immune-deficient mice, and a lipofection of an IFN-β-expressing plasmid was found to suppress the growth of subcutaneous tumors significantly. Finally, the IFN gene transfer was combined with syngeneic HSCT in murine osteosarcoma models. Intratumoral IFN-β gene transfer markedly suppressed the growth of vector-injected tumors and inhibited formation of spontaneous lung and liver metastases in syngeneic HSCT mice, and an infiltration of many immune cells was recognized in metastatic tumors of the treated mice. The treated mice showed no significant adverse events. A combination of intratumoral IFN gene transfer with autologous HSCT could be a promising therapeutic strategy for patients with sarcoma.

Direct cytotoxicity produced by adenoviral-mediated interferon α gene transfer in interferon-resistant cancer cells involves ER stress and caspase 4 activation

Over the past several years we have obtained considerable evidence indicating that adenoviruses-expressing interferon α (Ad-IFNα) can overcome resistance to the IFNα protein itself. Since cancer cells infected with Ad-IFNα also show high perinuclear cytoplasmic IFNα expression, we were interested in whether endoplasmic reticulum (ER) stress and cleavage of caspase 4 could have a major role in Ad-IFNα-produced cancer cell death. Indeed, procaspase 4 was upregulated and cleaved as early as 12 h after Ad-IFNα infection of the cancer cells, which co-localized with IFNα staining and ER tracker. In contrast, immortalized normal human urothelial cells, although exhibiting similar perinuclear IFNα staining, showed no cleaved caspase 4. Caspase 4 cleavage was not blocked by the caspase 8 specific inhibitor zIETD, indicating that caspase 4 activation was independent of caspase 8 activation. Blocking caspase 4 also inhibited activation of caspase 3 in Ad-IFNα containing cells. Finally, the cleaved form of caspase 4 (p10) was detected in Ad-IFNα-positive cancer cells from the urine of a patient following intravesical Ad-IFNα/Syn3 treatment. Therefore, ER stress and activation of caspase 4 appears to be an important mechanism involved in the direct cancer cell death produced by Ad-IFNα and also occurs in the clinical setting.

Direct gene transfer of adenoviral-mediated interferon α into human bladder cancer cells but not the bystander factors produced induces endoplasmic reticulum stress-related cytotoxicity

We have previously shown that adenoviral-mediated interferon α (Ad-IFNα) is cytotoxic both to cells that are sensitive to recombinant interferon α (IFNα) and to cells which are resistant to IFNα. The cancer cell-specific cytotoxic effects of Ad-IFNα involve three different mechanisms: 1. The direct effect of IFNα production causing cancer cell death in IFNα sensitive cells (1); 2. The direct effect of Ad-IFNα infection and high levels of IFNα expression in IFNα resistant cancer cells (2); and 3. The indirect effect of the Ad-IFNα bystander factors produced (2-4). After Ad-IFNα infection, the cells produce a large amount of perinuclear localized IFN protein. This protein over-load could be a major factor in the direct cancer cell death of those cells infected with Ad-IFNα compared with the indirect cytotoxic effects of the bystander factors produced. Here, we investigated whether a component of Ad-IFN-induced cell death involves protein overload-induced endoplasmic reticulum (ER) stress, using an IFNα-resistant human bladder cancer cell line (KU7), and the normal human urothelial cell line, TERT-NHUC, as preclinical models. We found that the two ER stress response pathways examined were activated in KU7 cells. In contrast, following treatment of the normal TERT-NHUC cells with Ad-IFNα, no ER stress signals were observed. In addition, no ER stress related changes were seen, when KU7 cells were exposed to conditioned medium from Ad-IFNα-treated KU7 cells, indicating that bystander produced cytotoxicity did not involve ER stress. After 24 h of Ad-IFNα infection, the KU7 cancer cells produced spliced X-box binding protein 1 and activating transcription factor 6 protein (ATF6), evoking an ER stress response that could contribute to Ad-IFNα induced apoptosis in these cancer cells. In addition, GADD153/CHOP, GADD34 and BAX were also subsequently modified following activation of the ER stress pathways, thereby signaling downstream effectors in a pro-apoptotic manner.

Bladder cancer: can we move beyond chemotherapy?

Since the advent of cisplatin-based chemotherapy, cytotoxic combination chemotherapy remains the mainstay of treatment for locally advanced and metastatic urothelial malignancies. The current paradigm of combining novel agents with cytotoxic chemotherapy without any understanding of the underlying biology of urothelial cancer has limited the impact of developing novel agents for this disease. Current research investigating the biology of bladder cancer, including the role of p53, EMT, EGFR-related pathways, and anti-angiogenic pathways, may potentially impact the future development of novel agents targeting urothelial malignancies. Additionally, the use of novel gene therapy to mediate enhanced interferon expression in the bladder using adenoviral vectors, and enhancing tumor recognition strategies using the immune system with vaccines and anti-CTLA4 antibodies, are of interest. It is hoped that through these efforts we may soon move beyond the traditional cytotoxic chemotherapy paradigm, developing combinations that are more active and less toxic for all patients with urothelial cancer.

Down-regulation of type I interferon receptor sensitizes bladder cancer cells to vesicular stomatitis virus-induced cell death

The intrinsic oncolytic specificity of vesicular stomatitis virus (VSV) is currently being exploited to develop alternative therapeutic strategies for bladder cancer and other cancers. Previously we reported that oncolytic VSV is a potent agent for intravesical treatment of high risk bladder cancer. We observed that VSV preferentially targeted bladder cancer cells resistant to type I interferon (IFN) treatment. The goal of the current study was to further elucidate the nature of the molecular defect of IFN signaling by which bladder cancer cells become susceptible to VSV infection. Using a tissue microarray composed of human bladder cancer cores, we observed that expression of type I IFN receptor (IFNAR) was decreased relative to normal bladder tissue. Advanced bladder cancers had even lower expression of IFNAR. We found that bladder cancer cells susceptible to VSV-induced lysis had low expression of IFNAR as well. We hypothesized that down-regulation of IFNAR in bladder cancer cells may be a molecular mechanism responsible for resistance to type I IFN treatment and sensitivity to VSV oncolysis. SiRNA knockdown of IFNAR indeed facilitated replication of VSV in cells previously resistant to VSV treatment. Blocking IFNAR with a neutralizing antibody showed a similar effect. Hence down-regulation of IFNAR in bladder cancer may be one of the primary molecular mechanisms for clinical IFN resistance. However, this also facilitates VSV replication and oncolysis in high risk bladder cancers and provides a basis for selecting bladder cancer patients for IFN or oncolytic VSV therapy in future clinical trials.