Successful transurethral intralesional BCG therapy of a bladder melanoma

Exploiting bacteria for cancer immunotherapy

Immunotherapy has revolutionized the treatment of cancer but continues to be constrained by limited response rates, acquired resistance, toxicities and high costs, which necessitates the development of new, innovative strategies. The discovery of a connection between the human microbiota and cancer dates back 4,000 years, when local infection was observed to result in tumour eradication in some individuals. However, the true oncological relevance of the intratumoural microbiota was not recognized until the turn of the twentieth century. The intratumoural microbiota can have pivotal roles in both the pathogenesis and treatment of cancer. In particular, intratumoural bacteria can either promote or inhibit cancer growth via remodelling of the tumour microenvironment. Over the past two decades, remarkable progress has been made preclinically in engineering bacteria as agents for cancer immunotherapy; some of these bacterial products have successfully reached the clinical stages of development. In this Review, we discuss the characteristics of intratumoural bacteria and their intricate interactions with the tumour microenvironment. We also describe the many strategies used to engineer bacteria for use in the treatment of cancer, summarizing contemporary data from completed and ongoing clinical trials. The work described herein highlights the potential of bacteria to transform the landscape of cancer therapy, bridging ancient wisdom with modern scientific innovation.

Drug Repurposing in the Chemotherapy of Infectious Diseases

Repurposing is a universal mechanism for innovation, from the evolution of feathers to the invention of Velcro tape. Repurposing is particularly attractive for drug development, given that it costs more than a billion dollars and takes longer than ten years to make a new drug from scratch. The COVID-19 pandemic has triggered a large number of drug repurposing activities. At the same time, it has highlighted potential pitfalls, in particular when concessions are made to the target product profile. Here, we discuss the pros and cons of drug repurposing for infectious diseases and analyze different ways of repurposing. We distinguish between opportunistic and rational approaches, i.e., just saving time and money by screening compounds that are already approved versus repurposing based on a particular target that is common to different pathogens. The latter can be further distinguished into divergent and convergent: points of attack that are divergent share common ancestry (e.g., prokaryotic targets in the apicoplast of malaria parasites), whereas those that are convergent arise from a shared lifestyle (e.g., the susceptibility of bacteria, parasites, and tumor cells to antifolates due to their high rate of DNA synthesis). We illustrate how such different scenarios can be capitalized on by using examples of drugs that have been repurposed to, from, or within the field of anti-infective chemotherapy.

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.

Effects of Mycobacterium bovis Calmette et Guérin (BCG) in oncotherapy: Bladder cancer and beyond

The Mycobacterium bovis Bacillus Calmette et Guérin (BCG) vaccine was generated in 1921 with the efforts of a team of investigators, Albert Calmette and Camille Guérin, dedicated to the determination to develop a vaccine against active tuberculosis (TB) disease. Since then, BCG vaccination is used globally for protection against childhood and disseminated TB; however, its efficacy at protecting against pulmonary TB in adult and aging populations is highly variable. Due to the BCG generated immunity, this vaccine later proved to have an antitumor activity; though the standing mechanisms behind are still unclear. Recent studies indicate that both innate and adaptive cell responses may play an important role in BCG eradication and prevention of bladder cancer. Thus, cells such as natural killer (NK) cells, macrophages, dendritic cells, neutrophils but also MHC-restricted CD4 and CD8 T cells and γδ T cells may play an important role and can be one the main effectors in BCG therapy. Here, we discuss the role of BCG therapy in bladder cancer and other cancers, including current strategies and their impact on the generation and sustainability of protective antitumor immunity against bladder cancer.

100 years of Bacillus Calmette-Guérin immunotherapy: from cattle to COVID-19

Bacillus Calmette-Guérin (BCG) is the most widely used vaccine worldwide and has been used to prevent tuberculosis for a century. BCG also stimulates an anti-tumour immune response, which urologists have harnessed for the treatment of non-muscle-invasive bladder cancer. A growing body of evidence indicates that BCG offers protection against various non-mycobacterial and viral infections. The non-specific effects of BCG occur via the induction of trained immunity and form the basis for the hypothesis that BCG vaccination could be used to protect against the severity of coronavirus disease 2019 (COVID-19). This Perspective article highlights key milestones in the 100-year history of BCG and projects its potential role in the COVID-19 pandemic.

Bacteria-based immune therapies for cancer treatment

Engineered bacterial therapies that target the tumor immune landscape offer a new class of cancer immunotherapy. Salmonella enterica and Listeria monocytogenes are two species of bacteria that have been engineered to specifically target tumors and serve as delivery vessels for immunotherapies. Therapeutic bacteria have been engineered to deliver cytokines, gene silencing shRNA, and tumor associated antigens that increase immune activation. Bacterial therapies stimulate both the innate and adaptive immune system, change the immune dynamics of the tumor microenvironment, and offer unique strategies for targeting tumors. Bacteria have innate adjuvant properties, which enable both the delivered molecules and the bacteria themselves to stimulate immune responses. Bacterial immunotherapies that deliver cytokines and tumor-associated antigens have demonstrated clinical efficacy. Harnessing the diverse set of mechanisms that Salmonella and Listeria use to alter the tumor-immune landscape has the potential to generate many new and effective immunotherapies.

In situ vaccination with nanoparticles for cancer immunotherapy: understanding the immunology

FDA approval of anti-CTLA4 in 2011 for melanoma immunotherapy was paradigm shifting and dramatically accelerated cancer immunotherapy research. The investment and effort have been exceptionally large, with a commensurate impressive pace of discovery. Historical and current research has validated the following key points: tumors are recognized by the immune system; tumors develop an immunosuppressive environment which suppresses the antitumor immune response; successful immunotherapy must overcome that tumor-mediated immunosuppression. While cancer immunotherapy research expanded, a parallel effort developing nanoparticles (NP) for cancer diagnosis and therapy also received major investment and expanded. Initially the two efforts appeared to have minimal synergy. Systemically administered nanoparticles are rapidly ingested by phagocytic leukocytes, and therefore nanotechnologists developed strategies to avoid NP ingestion by leukocytes in order to accomplish nanoparticle accumulation in tumors rather than liver and spleen. Recently, nanotechnology and cancer immunotherapy have increasingly merged since phagocytic leukocytes are the key to reversing the local tumor immunosuppression and the tendency of NP to be phagocytosed can be exploited to manipulate phagocytes for immunotherapy. This review focuses on in situ vaccination (ISV), an immunotherapy approach that can utilize direct injection of immunostimulatory reagents, including NPs, into tumors to disrupt the local immunosuppression, stimulate effective immune response against the treated tumor, and most importantly, generate a systemic antitumor immune response to eliminate metastatic tumors. While there are many specific options for using NP for ISV (reviewed further in this special issue), this review focuses on immunology concepts needed to understand and design successful NP ISV approaches.

Conservative management of primary malignant melanoma of the bladder: a case report

Background

Primary malignant melanoma (PMM) of the bladder represents a very rare clinic-pathologic entity. Given the rarity of the disease, the best treatment option is not well recognized.

Case presentation

We describe a case of neoplasm of the bladder in a 74 years-old Caucasian man presenting with massive hematuria. Based on clinical, instrumental and histological findings a diagnosis of PMM was made. The patient underwent trans urethral resection of bladder tumor plus intravesical Bacillus Calmette–Guérin.

Conclusions

To make a correct diagnosis, clinical history, endoscopic evaluation, histopathological examination and immunohistochemistry, are necessary. Multidisciplinary evaluation is required to discriminate primary from metastatic malignant melanoma.

William B. Coley: His Hypothesis, His Toxin, and the Birth of Immunotherapy

In recent years, immunotherapy has been the focus of great interest to researchers, clinicians, and the general public. Traditionally cancer therapy has been thought to be limited to surgery, radiation therapy, or chemotherapy. Some clinicians have considered it the so-called fifth pillar of cancer therapy, following surgery, cytotoxic chemotherapy, radiation, and targeted therapy. However, the origins of immunotherapy in cancer treatment reach back at least into the nineteenth century. This article reviews the origins, development, and future of immunotherapy.

Immunotherapy for the Treatment of Urothelial Carcinoma

PURPOSE

We review the biological mechanisms of action, clinical safety and efficacy of immunotherapies for urothelial carcinoma. We also describe current areas of research in immunotherapy, and highlight ongoing trials and promising and novel investigational agents.

MATERIALS AND METHODS

Data were obtained by a search of PubMed®, ClinicalTrials.gov and Cochrane databases for English language articles published through February 2016. Applicable abstracts from recent Society of Urologic Oncology, European Association of Urology, American Urological Association and ASCO® meetings were used.

RESULTS

Bacillus Calmette-Guérin is one of the most successful immunotherapies in cancer treatment and remains the gold standard of care for patients with high risk, nonmuscle invasive bladder cancer, with initial response rates of approximately 70%. However, with the exception of valrubicin and standard chemotherapeutics there is a paucity of available treatment options for patients with recurrence or progression to more advanced disease. Recently there has been significant interest in novel immunotherapeutic agents in the management of cases where bacillus Calmette-Guérin fails, as well as cases of more advanced cancer. These investigational therapies can generally be classified into several broad categories, including recombinant bacillus Calmette-Guérin and cell wall derived therapies, cytokines, gene therapy, cancer vaccines, immune checkpoint inhibitors, oncolytic viruses, adoptive immunotherapies and immune agonists, as well as several additional immunomodulatory agents. The majority of these agents are currently under investigation in phase I or II clinical trials. Recently investigators reported evidence that inhibition of the PD-1/PD-L1 pathway has clinical activity in patients with advanced bladder cancer. These findings, along with successful phase III trials and U.S. Food and Drug Administration approvals of other checkpoint inhibitors in melanoma, nonsmall cell lung cancer and renal cell carcinoma, ultimately led to Food and Drug Administration approval of atezolizumab for advanced disease, the first new treatment approved for advanced urothelial carcinoma in 20 years.

CONCLUSIONS

While bacillus Calmette-Guérin has demonstrated significant clinical efficacy in the treatment of patients with bladder cancer, additional therapies are needed for those in whom bacillus Calmette-Guérin fails, as well as for those with advanced disease. Immunotherapy for urothelial carcinoma remains a promising and active area of research, and numerous agents, particularly the monoclonal antibodies targeting checkpoint inhibition pathways, are showing encouraging signs of clinical activity.

Melanoma of the urinary bladder: a review of the literature

Background. Melanomas of the urinary bladder and urethra are rare. Aims. To review the literature on the disease. Methods. Various Internet databases were used to identify reported cases of the disease. Results. Less than 30 cases of primary melanoma of the urinary bladder and urethra have been reported in the literature and they have been associated with melanosis and commonly with metastases. The lesions may be primary or metastatic with no gender preference. The diagnostic features include pigmented raised lesions which histologically exhibit spindled or epitheliod cells, necrosis, mitotic figures, and atypical melanocytes. Immunohistochemically they stain positively with S100; HMB45; and other melanocyte markers, but negatively with Keratin and Vimentin. The treatment involves excision and possibly IL-2. The prognostic factors include size and depth of invasion as well as metastatic lesions. Conclusions. Less than 30 cases (about 24 cases) of the disease have been reported. There are also reports of metastatic melanomas of the urinary bladder emanating from primary melanomas originating elsewhere. Diagnosis of the primary disease is based upon the histological appearance of the lesion, positive staining with S100 and HMB45, and evidence of absence of melanoma elsewhere. Primary melanoma of the bladder is usually a fatal lesion.

History of bacillus Calmette-Guerin and bladder cancer: an immunotherapy success story

PURPOSE

We review how the bacillus Calmette-Guerin vaccine evolved to become standard therapy for superficial bladder cancer.

MATERIALS AND METHODS

We reviewed the historical literature describing the origin of the bacillus Calmette-Guerin vaccine as an anticancer agent and its singular success as the most effective immunotherapy used against a human neoplasm.

RESULTS

The association between tuberculosis and cancer, and the demonstration that bacillus Calmette-Guerin invoked immunological reactivity, inhibiting tumor growth in experimental animal models, led to clinical trials showing that intravesical bacillus Calmette-Guerin eradicated and prevented recurrence of superficial bladder tumors.

CONCLUSIONS

For the last 3 decades bacillus Calmette-Guerin therapy has remained the most effective local therapy for superficial bladder cancer, an outstanding example of successful translational medicine in urology.

Prolonged survival of patients receiving active immunotherapy with Canvaxin therapeutic polyvalent vaccine after complete resection of melanoma metastatic to regional lymph nodes

OBJECTIVE

To determine whether adjuvant postoperative active specific immunotherapy with a therapeutic polyvalent vaccine (PV) called Canvaxin can prolong survival following complete resection of melanoma metastatic to regional nodes (American Joint Committee on Cancer [AJCC] stage III melanoma).

SUMMARY BACKGROUND DATA

Despite complete lymphadenectomy, 5-year overall survival (OS) for patients with melanoma metastatic to regional lymph nodes is only 20% to 50%, depending on the number of tumor-involved nodes. In 1984, the authors began phase II trials of Canvaxin PV as postsurgical adjuvant therapy for AJCC stage III melanoma.

METHODS

Patients who received PV between 1984 and 1998 were compared with patients who did not receive PV postsurgical therapy between 1971 and 1998. The seven covariates recently defined by the AJCC Melanoma Staging Committee (number of metastatic nodes, palpable status, ulceration, age, primary site, pT stage, and gender) were included by Cox regression in a multivariate model of OS. A computerized program matched PV and non-PV patients by these covariates.

RESULTS

Of 2,602 patients who underwent complete lymphadenectomy for AJCC stage III melanoma with regional nodal metastases and were followed up by the same team of oncologists between 1971 and 1998, 935 received PV and 1,667 did not. Median OS and 5-year OS were significantly higher in PV than non-PV patients (56.4 vs. 31.9 months and 49% vs. 37%, respectively; P =.0001). When the non-PV patients were matched by the four most significant covariates, 447 matched pairs were formed between patients seen before or after January 1, 1985, and the OS was not different between the two time periods ( P=.789). However, when the PV patients were matched with non-PV patients by six covariates forming 739 pairs, the PV patients survived longer ( P=.0001). Detailed analysis of the 1,505 patients who were seen or who began vaccine therapy within 4 months after lymphadenectomy, and who had more complete data on the seven prognostic covariates showed that median OS and 5-year OS were higher in 445 PV patients than in 1,060 non-PV patients: 70.4 versus 31 months and 52% versus 37%, respectively (P =.0001). Multivariate Cox regression analysis identified six significant prognostic factors: number of metastatic nodes, size of metastatic nodes, pT stage, ulceration, age, and PV therapy. PV therapy reduced the relative risk of death to 0.64 (95% confidence interval, 0.55-0.76) ( P=.0001); sex and site of primary were of borderline significance.

CONCLUSIONS

This large single-institution study independently confirmed the significance of prognostic covariates in the new AJCC staging system. By using modern statistical methods that controlled for all known prognostic factors, it also demonstrated PV's ability to significantly enhance OS. A multicenter phase III randomized trial is underway to validate the efficacy of PV as a postsurgical adjuvant.

Production and characterization of xenogeneic antisera to tumor-associated antigen(s)

Tumor-associated antigen(s) from a specimen of human malignant melanoma and from spent culture medium of a melanoma cell line were extracted and purified. The incidence of antibody activity to these antigens, in sera from cancer patients with neoplasms of various histologic types, was higher (65--83%) than normal donors' (19--25%) by the complement fixation assay. These purified antigens were then used to raise antisera in rabbits and sheep. After absorption with various human normal tissues, these antisera reacted against melanoma, sarcoma, and carcinoma extracts, but not against human normal liver, skin, or muscle extracts. However, the antisera showed reactivity against a human fetal homogenate. Results indicate that the xenogeneic antisera contained antibodies to fetal antigens and to tumor-associated antigen(s). Xenogeneic antisera could be used to purify tumor-associated antigens and oncofetal antigen(s) from crude extracts by affinity chromatography.