Interferon alpha for the treatment of superficial bladder cancer

The role of immunotherapy in urological cancers

Immunotherapy is defined as a therapeutic approach that targets or manipulates the immune system. A deeper understanding of the cellular and molecular composition of the tumour environment, as well as the mechanisms controlling the immune system, has made possible the development and clinical investigation of many innovative cancer therapies. Historically, immunotherapy has played an essential role in treating urologic malignancies, while in the modern era, the development of immune checkpoint inhibitors (ICIs) has been critical to urology. Urothelial carcinoma is a common type of cancer in the genitourinary system, and treatment strategies in this area are constantly evolving. Intravesical and systemic immunotherapeutic agents have begun to be used increasingly frequently in treating urothelial carcinoma. These agents increase the anti-tumour response by affecting the body's defence mechanisms. Immunotherapeutic agents used in urothelial carcinoma include various options such as BCG, interferon, anti-PD-1 (pembrolizumab, nivolumab) and anti-PD-L1 (atezolizumab, avelumab, durvalumab). Renal cell carcinoma (RCC) has been known for many years as a tumour with unique sensitivity to immunotherapies. The recent emergence of ICIs that block PD-1/PD-L1 (pembrolizumab, nivolumab, atezolizumab) or CTLA4 (ipilimumab) signalling pathways has reestablished systemic immunotherapy as central to the treatment of advanced RCC. In light of randomized clinical trials conducted with increasing interest in the application of immunotherapies in the adjuvant setting, combination therapies (nivolumab/ipilimumab, nivolumab/cabozantinib, pembrolizumab/ axitinib, pembrolizumab/lenvantinib) have become the standard first-line treatment of metastatic RCC. Prostate cancer is in the immunologically "cold" tumour category; on the contrary, in recent years, immunotherapeutic agents have come to the fore as an essential area in the treatment of this disease. Especially in the treatment of castration-resistant prostate cancer, immunotherapeutic agents constitute an alternative treatment method besides androgen deprivation therapy and chemotherapy. Ipilimumab, nivolumab, pembrolizumab, atezolizumab, and Sipuleucel T (Vaccine-based) are promising alternative treatment options. Considering ongoing randomized clinical trials, immunotherapeutic agents promise to transform the uro-oncology field significantly. In this review, we aimed to summarize the role of immunotherapy in urothelial, renal and prostate cancer in the light of randomized clinical trials.

Enhancement of intravesical delivery with Syn3 potentiates interferon-alpha2b gene therapy for superficial bladder cancer

Intravesical administration of interferon alpha-2b protein (IFN) has been successfully used in the treatment of patients with superficial bladder tumors. Local dosing of IFN minimizes well-known systemic side effects of the drug, but exposure to bladder tumors is limited by the duration of instillation and transient concentrations achieved in the urothelium. Intravesical delivery of the gene encoding interferon results in an alternative strategy for IFN-based therapy of the disease, enabling sustained exposure of IFN protein that results from production by tumor and non-tumor cells in the urothelium. Efficient gene delivery and expression of IFN has been achieved using a recombinant adenovirus gene delivery system (rAd-IFN) in conjunction with the novel small molecule excipient Syn3. Studies with rAd-IFN/Syn3 in animal models result in urine concentrations of IFN that persisted for weeks and correlated with potent anti-tumor effects. The objective of this review is to communicate the rationale and preclinical findings that support ongoing clinical investigation of intravesical rAd-IFN/Syn3 in superficial bladder cancer.

Role of Th1 and Th2 cytokines in BCG-induced IFN-gamma production: cytokine promotion and simulation of BCG effect

Induction of a T-helper-type 1 (Th1) immune response is indispensable for successful treatment of superficial bladder cancer with BCG. In this study possible involvement of various cytokines in BCG action as well as their potential roles in enhancing and mimicking BCG effect were explored. In immunocompetent cell cultures, IFN-gamma, a major Th1 cytokine, appears to be a late responsive cytokine to BCG stimulation. Its induction requires involvement of various endogenously produced Th1 and Th2 cytokines. Functional abolishment of any one of these cytokines (IL-2, IL-6, IL-12, IL-18, GMCSF, TNF-alpha, or IFN-alpha, except IL-10) by neutralizing antibodies leads to reduced IFN-gamma production (19-82% inhibition in mouse and 44-77% inhibition in human systems, respectively). In mice cytokines IL-2, IL-12, IL-18, and GMCSF are observed to synergize with BCG for IFN-gamma production, whereas in human cytokines IL-2, IL-12, TNF-alpha, and IFN-alpha exhibit similar synergistic effects. Rational combinations of these Th1-stimulating cytokines (IL-12 plus IL-18 in mice and IL-2 plus IL-12 in humans, respectively) dramatically up-regulate IFN-gamma production that is incomparably superior to BCG for induction of this cytokine. These results suggest that combined Th1-stimulating cytokines and combinations of BCG plus selected Th1-stimulating cytokines are rational candidates for further study in the treatment of bladder cancer patients.

Recombinant bacille Calmette-Guérin (BCG) expressing human interferon-alpha 2B demonstrates enhanced immunogenicity

To increase its immunostimulatory properties, BCG was genetically engineered to secrete recombinant human interferon-alpha 2B (rhIFN-alpha) under control of the mycobacterial heat shock protein (hsp)60 promoter and the alpha antigen signal sequence. Expression of rhIFN-alpha was readily detectable by ELISA and on Western blotting. When compared with control BCG, rhIFN-alpha BCG was substantially more active in inducing the production of IFN-gamma and IFN-inducible protein 10 (IP-10) from human peripheral blood mononuclear cells, while IL-10 production was correspondingly decreased. These effects were reversible upon antibody neutralization of rhIFN-alpha. Among 10 patients tested, rhIFN-alpha BCG enhanced IFN-gamma production in all patients ranging from 1.4- to 23.7-fold with a general trend toward greatest enhancement among those with weakest baseline responses to control BCG. Correspondingly, rhIFN-alpha BCG decreased IL-10 production in all patients by 1.2-4.8-fold. The onset of IFN-gamma production induced by rhIFN-alpha BCG was also more rapid, occurring within 4 h after stimulation versus > 24 h with wild-type BCG. The observation that the maximum IFN-gamma induction depends on the simultaneous presence of both IFN-alpha and BCG highlights the advantages of rhIFN-alpha BCG. Taken together, these immunostimulatory properties of rhIFN-alpha BCG suggest that it may be a superior agent for immunotherapeutic protocols involving live BCG in humans.