First-in-human Intravesical Delivery of Pembrolizumab Identifies Immune Activation in Bladder Cancer Unresponsive to Bacillus Calmette-Guérin

Advancements in Urothelial Cancer Care: Optimizing Treatment for Your Patient

The standard treatment paradigm for muscle invasive bladder cancer has been neoadjuvant cisplatin-based chemotherapy followed by radical cystectomy. However, efforts are ongoing to personalize treatment by incorporating biomarkers to better guide treatment selection. In addition, bladder preservation strategies are aimed at avoiding cystectomy in well-selected patients. Similarly, in the metastatic urothelial cancer space, the standard frontline treatment option of platinum-based chemotherapy has changed with the availability of data from EV-302 trial, making the combination of enfortumab vedotin (EV) and pembrolizumab the preferred first-line treatment option. Here, we examine the optimization of treatment intensity and sequencing, focusing on the challenges and opportunities associated with EV/pembrolizumab therapy, including managing toxicities and exploring alternative dosing approaches. Together, these articles provide a comprehensive overview of contemporary strategies in bladder cancer management, highlighting the importance of individualized treatment approaches, ongoing research, and multidisciplinary collaboration to improve patient outcomes in this complex disease landscape.

Enhancing Therapeutic Efficacy and Safety of Immune Checkpoint Inhibition for Bladder Cancer: A Comparative Analysis of Injectable vs. Intravesical Administration

Bladder cancer (BC) presents a significant global health burden, characterized by high recurrence rates post-initial treatment. Gender differences in BC prevalence and response to therapy emphasize the importance of personalized treatment strategies. While Bacillus Calmette-Guérin (BCG) remains a cornerstone of BC therapy, resistance poses a challenge, necessitating alternative strategies. Immune checkpoint inhibitors (ICIs) have shown promise, yet systemic toxicity raises concern. Intravesical administration of ICIs offers a potential solution, with recent studies demonstrating the feasibility and efficacy of intravesical pembrolizumab. Although systemic toxicity remains a concern, its localized administration may mitigate adverse events. Additionally, liposomal delivery of ICIs exhibits promises in enhancing drug penetration and reducing toxicity. Novel imaging modalities compatible with Vesical Imaging-Reporting and Data System (VI-RADS) and capable of predicting high-grade bladder cancer can aid the pre-operative shared decision making of patient and surgeon. Future research should focus on refining treatment approaches, optimizing dosing regimens, and leveraging advanced imaging techniques to improve patient outcomes. In conclusion, intravesical immunotherapy presents a promising avenue for BC treatment, offering enhanced therapeutic effectiveness while minimizing systemic toxicity. Continued research efforts are essential to validate these findings and optimize intravesical immunotherapy's role in BC management, ultimately improving patient outcomes.

HIVEC as an alternative option in non-muscle-invasive bladder cancer: Experiences from a high-volume center

BACKGROUND

High risk non-muscle invasive bladder cancer (NMIBC) is usually treated with intravesical BCG-therapy. In case of BCG failure radical cystectomy (RC) is the treatment of choice. Nevertheless, many patients are unfit for or unwilling to undergo RC. Hyperthermic intravesical chemotherapy (HIVEC) is a promising bladder sparing therapy in such cases. It was the purpose of the study to evaluate the efficacy of HIVEC in patients with BCG failure as well as in BCG naïve patients in case of BCG shortage or given contra-indications for BCG.

METHODS

We analyzed the first 60 patients who received hyperthermic intravesical chemotherapy (HIVEC) at our department. The therapy regimen consisted of an induction course of 6 weekly sessions, followed by a maintenance course with 6 monthly sessions. Fluorescence cystoscopy with urine cytology and bladder mapping was performed after completion of induction and maintenance therapy at 3 and 12 months. About 68.6 % had received a recurrence after or during BCG treatment, 55% of the subjects were BCG-unresponsive NMIBC according to EAU guidelines.

RESULTS

The median follow up was 12 months with 12 cycles of HIVEC therapy being administered on average, representing completion of induction and maintenance therapy with 6 cycles each. The 1- and 2-year recurrence-free-survival (RFS) was 67% and 40% respectively. Only one out of 60 patients developed progression to muscle invasion with progression-free-survival (PFS) of 98% at 2 years. No statistical differences were found in RFS for patients failure to BCG compared to patients that were BCG-naïve (BCG unresponsive vs. BCG-naïve) and patients that carried carcinoma in situ (CIS) compared to patients without CIS (CIS vs. no CIS).

CONCLUSION

Chemohyperthermia using HIVEC results in high recurrence-free survival and a 2-year progression-free survival rate of 98% with a bladder preservation rate of almost 80%. Comparing our data, HIVEC shows better oncological results together with better tolerability and safety making HIVEC a good alternative for patients who refuse radical cystectomy or who are ineligible for radical cystectomy.

Global real-world experiences with pembrolizumab in advanced urothelial carcinoma after platinum-based chemotherapy: the ARON-2 study

BACKGROUND

Immune checkpoint inhibitors have changed previous treatment paradigm of advanced urothelial carcinoma (UC). The ARON-2 study (NCT05290038) aimed to assess the real-world effectiveness of pembrolizumab in patients recurred or progressed after platinum-based chemotherapy.

PATIENTS AND METHODS

Medical records of patients with documented metastatic UC treated by pembrolizumab as second-line therapy were retrospectively collected from 88 institutions in 23 countries. Patients were assessed for overall survival (OS), progression-free survival (PFS) and overall response rate (ORR). Cox proportional hazards models were adopted to explore the presence of prognostic factors.

RESULTS

In total, 836 patients were included: 544 patients (65%) received pembrolizumab after progression to first-line platinum-based chemotherapy in the metastatic setting (cohort A) and 292 (35%) after recurring within < 12 months since the completion of adjuvant or neoadjuvant chemotherapy (cohort B). The median follow-up time was 15.3 months. The median OS and the ORR were 10.5 months and 31% in the overall study population, 9.1 months and 29% in cohort A and 14.6 months and 37% in cohort B. At multivariate analysis, ECOG-PS ≥ 2, bone metastases, liver metastases and pembrolizumab setting (cohort A vs B) proved to be significantly associated with worst OS and PFS. Stratified by the presence of 0, 1-2 or 3-4 prognostic factors, the median OS was 29.4, 12.5 and 4.1 months (p < 0.001), while the median PFS was 12.2, 6.4 and 2.8 months, respectively (p < 0.001).

CONCLUSIONS

Our study confirms that pembrolizumab is effective in the advanced UC real-world context, showing outcome differences between patients recurred or progressed after platinum-based chemotherapy.

Spatial comparison of molecular features associated with resistance to pembrolizumab in BCG unresponsive bladder cancer

Intravenous immune checkpoint inhibition achieves a 40% 3-month response in BCG-unresponsive non-muscle invasive bladder cancer (NMIBC) with carcinoma in situ. Yet, only half of the early responders will continue to be disease-free by 12 months, and resistance mechanisms are poorly defined. We performed spatial profiling of BCG-unresponsive tumors from patients responsive or resistant to intravenous pembrolizumab treatment, analyzing samples both before initiating and 3 months post-intravenous pembrolizumab treatment. We analyzed 119 regions of interest, which included 59 pairs of epithelial and adjacent stromal segments across five patients: two responders and three non-responders. We demonstrate that BCG unresponsive tumors with an inflamed PanCK+ tumor area and an infiltrated stromal segment respond better to intravenous pembrolizumab. Furthermore, using segment-specific gene signatures generated from a cohort of BCG unresponsive NMIBC treated with intravesical BCG+pembrolizumab, we find that non-inflamed, immune-cold tumors that do not respond to intravenous pembrolizumab exhibit a favorable outcome to the combined application of BCG and pembrolizumab. For the first time, we have identified molecular features of tumors associated with response and resistance to intravenous pembrolizumab in BCG unresponsive NMIBCs. Further research with more patients and alternative checkpoint inhibitors is essential to validate our findings. We anticipate that using a transcriptomics signature like the one described here can help identify tumors with a higher possibility of responding to intravenous pembrolizumab.

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.

Revolutionizing Treatment: Breakthrough Approaches for BCG-Unresponsive Non-Muscle-Invasive Bladder Cancer

Bladder cancer is the 10th most popular cancer in the world, and non-muscle-invasive bladder cancer (NMIBC) is diagnosed in ~80% of all cases. Treatments for NMIBC include transurethral resection of the bladder tumor (TURBT) and intravesical instillations of Bacillus Calmette-Guérin (BCG). Treatment of BCG-unresponsive tumors is scarce and usually leads to Radical Cystectomy. In this paper, we review recent advancements in conservative treatment of BCG-unresponsive tumors. The main focus of the paper is FDA-approved medications: Pembrolizumab and Nadofaragene Firadenovec (Adstiladrin). Other, less researched therapeutic possibilities are also included, namely: N-803 immunotherapy, TAR-200 and TAR-210 intravesical delivery systems and combined Cabazitaxel, Gemcitabine and Cisplatin chemotherapy. Conservative treatment and delaying radical cystectomy would greatly benefit patients' quality of life; it is undoubtedly the future of BCG-unresponsive NMIBC.

The SUB-urothelial DUrvalumab InjEction-1 (SUBDUE-1) trial: first-in-human trial in patients with bladder cancer

OBJECTIVES

To assess the safety of sub-urothelial injection of durvalumab and examine the impact on tissue and circulating immune cell populations.

PATIENTS AND METHODS

The patients were chemotherapy and immunotherapy naïve (bacille Calmette-Guérin allowed) with non-metastatic muscle-invasive bladder cancer or non-muscle-invasive bladder cancer planned for radical cystectomy (RC). The study was a Phase Ib 3 + 3 dose-escalation design with sub-urothelial injection of durvalumab at three pre-determined doses (25, 75, 150 mg) diluted in 25 mL normal saline, injected at 25 locations (25 × 1 mL injections), at least 2 weeks before RC.

RESULTS

A total of 11 patients were recruited (10 male, one female). No significant changes were reported on American Urological Association Symptom Score or O'Leary Interstitial Cystitis Scale. In all, 14 adverse events (AEs) were reported (10 Grade 1, three Grade 2, one Grade 3), none considered immune-related. No Grade 4 or 5 AEs were recorded. All the patients underwent RC. Tissue immune populations changed following durvalumab injection (P = 0.012), with a statistically significant increase in M2-macrophage (CD163) when comparing the 25-150 mg dose (P = 0.021). Basal/mixed cancers showed a larger CD163 increase than luminal cancers (P = 0.033).

CONCLUSION

Sub-urothelial injection of durvalumab is feasible and safe without immune-related AEs and shows local immunological effects.

Urinary bother, Urinalysis, and Two-Year Efficacy Follow-Up Results of Phase I Trial of Intravesical Bacillus Calmette-Guérin Combined with Intravenous Pembrolizumab in Recurrent or Persistent High-Grade Non-Muscle-Invasive Bladder Cancer after Previous Bacillus Calmette-Guérin Treatment

OBJECTIVE

To report urinary bother, urinalysis changes, disease-free survival (DFS), and overall survival (OS) over 2 years for subjects enrolled in a phase I dose-escalation trial (NCT02324582) of intravesical Bacillus Calmette-Guérin (BCG) in combination with systemic pembrolizumab for recurrent or persistent high-grade non-muscle invasive bladder cancer (HGNMIBC).

METHODS

Eighteen patients consented to the study. Five were screen failures. Clinical activity was determined using cystoscopy and cytology with a biopsy of suspicious lesions. Urinalysis and International Prostate symptom score were assessed at pre-treatment, Week 10 (during combined BCG and pembrolizumab treatment), and 3 and 6 months from treatment completion. IPSS was analyzed using a mixed-model repeated measures analysis. A Chi-square test was used to compare urinalysis results at each interval.

RESULTS

The pathologic disease stage after restaging transurethral resection and before treatment was pTa in 6 (46.2%), CIS in 6 (46.2%), and pT1 in 1 (7.7%). There was no increase in reported urinary bother throughout treatment. Quality of life measurements demonstrated no change in subjective burden. On urinalysis, we did not observe significant differences at 3 months compared to baseline evaluation. At 12 months, the DFS and OS were 69.23% and 92.31%, respectively. At 24 months, the DFS and OS were 38.46% and 92.31%, respectively.

CONCLUSIONS

Treatment with BCG combined with intravenous pembrolizumab is not showing increased urinary bother or adverse urinalysis changes. Two-year response data is promising and await confirmation in the phase III study (Keynote 676).

Targeted therapies in bladder cancer: signaling pathways, applications, and challenges

Bladder cancer (BC) is one of the most prevalent malignancies in men. Understanding molecular characteristics via studying signaling pathways has made tremendous breakthroughs in BC therapies. Thus, targeted therapies including immune checkpoint inhibitors (ICIs), antibody-drug conjugates (ADCs), and tyrosine kinase inhibitor (TKI) have markedly improved advanced BC outcomes over the last few years. However, the considerable patients still progress after a period of treatment with current therapeutic regimens. Therefore, it is crucial to guide future drug development to improve BC survival, based on the molecular characteristics of BC and clinical outcomes of existing drugs. In this perspective, we summarize the applications and benefits of these targeted drugs and highlight our understanding of mechanisms of low response rates and immune escape of ICIs, ADCs toxicity, and TKI resistance. We also discuss potential solutions to these problems. In addition, we underscore the future drug development of targeting metabolic reprogramming and cancer stem cells (CSCs) with a deep understanding of their signaling pathways features. We expect that finding biomarkers, developing novo drugs and designing clinical trials with precisely selected patients and rationalized drugs will dramatically improve the quality of life and survival of patients with advanced BC.

Novel immunotherapeutic options for BCG-unresponsive high-risk non-muscle-invasive bladder cancer

BACKGROUND

High-risk non-muscle-invasive bladder cancer (HR-NMIBC) presents a challenge to many physicians due to its ability to resist Bacillus Calmette-Guérin (BCG) intravesical therapy and the substantial rate of progression into muscle-invasive bladder cancer (MIBC). Patients who are BCG-unresponsive have worse prognosis and thus require further management including radical cystectomy (RC), which significantly impacts quality of life. Moreover, the ongoing worldwide shortage of BCG warrants the need for policies that prioritize drug use and utilize alternative treatment strategies. Hence, there is a significant unmet need for bladder preserving therapy in this subset of patients.

METHODS

To address this issue, we searched the relevant literature in PUBMED for articles published from 2019 through May of 2023 using appropriate keywords. All clinical trials of patients with HR-NMIBC treated with immune-related agents were retrieved from clinicaltrials.gov.

FINDINGS AND FUTURE PERSPECTIVES

Exploratory treatments for BCG-Unresponsive HR-NMIBC included immune checkpoint inhibitors (ICI), oncolytic viral therapy, cytokine agonists, and other immunomodulators targeting TLR, EpCaM, FGFR, MetAP2, and IDO1. Some combination therapies have been found to work synergistically and are preferred therapeutically over monotherapy. Three drugs-pembrolizumab, valrubicin, and most recently, nadofaragene firadenovec-vncg-have been FDA approved for the treatment of BCG-unresponsive NMIBC in patients who are ineligible for or decline RC. However, all explored treatment options tend to postpone RC rather than provide long-term disease control. Additional combination strategies need to be studied to enhance the effects of immunotherapy. Despite the challenges faced in finding effective therapies, many potential treatments are currently under investigation. Addressing the landscape of biomarkers, mechanisms of progression, BCG resistance, and trial design challenges in HR-NMIBC is essential for the discovery of new targets and the development of effective treatments.

Optimizing outcomes for high-risk, non-muscle-invasive bladder cancer: The evolving role of PD-(L)1 inhibition

Transurethral resection of bladder tumor followed by intravesical Bacillus Calmette-Guérin (BCG) is the standard of care in high-risk, non-muscle-invasive bladder cancer (NMIBC). Although many patients respond, recurrence and progression are common. In addition, patients may be unable to receive induction + maintenance due to intolerance or supply issues. Therefore, alternative treatment options are urgently required. Programmed cell death (ligand) 1 (PD-[L]1) inhibitors show clinical benefit in phase 1/2 trials in BCG-unresponsive NMIBC patients. This review presents the status of PD-(L)1 inhibition in high-risk NMIBC and discusses future directions. PubMed and Google scholar were searched for articles relating to NMIBC immunotherapy and ClinicalTrials.gov for planned and ongoing clinical trials. Preclinical and early clinical studies show that BCG upregulates PD-L1 expression in bladder cancer cells and, when combined with a PD-(L)1 inhibitor, a potent antitumor response is activated. Based on this mechanism, several PD-(L)1 inhibitors are in phase 3 trials in BCG-naïve, high-risk NMIBC in combination with BCG. Whereas PD-(L)1 inhibitors are well characterized in patients with advanced malignancies, the impact of immune-related adverse events (irAE) on the benefit/risk ratio in NMIBC should be determined. Alternative routes to intravenous administration, like subcutaneous and intravesical administration, may facilitate adherence and access. The outcomes of combination of PD-(L)1 inhibitors and BCG in NMIBC are highly anticipated. There will be a need to address treatment resources, optimal management of irAEs and education and training related to use of this therapy in clinical practice.

A Spatial Comparison of Molecular Features Associated with Resistance to Pembrolizumab in BCG Unresponsive Bladder Cancer

Background

Intravenous immune checkpoint inhibition achieves a 40% three-month response in BCG-unresponsive non-muscle invasive bladder cancer (NMIBC) with carcinoma in situ (CIS). Yet only half of early responders will continue to be disease free by 12 months, and resistance mechanisms are poorly defined.

Objective

We assessed the molecular features associated with response to immunotherapy in BCG unresponsive non-muscle invasive bladder cancers treated with pembrolizumab.

Design Setting and Participants

We performed digital spatial profiling (DSP) of BCG unresponsive NMIBC tumors before and after IV pembrolizumab therapy.

Intervention

Pembrolizumab was administered intravenously in patients with NMIBC at the time of recurrence after BCG therapy. Biopsies were obtained before starting IV pembrolizumab and three months post-treatment.

Outcomes and Statistical Analysis

Spatial gene expression profiling of the tumor niche pre- and post IV pembrolizumab.

Results and Limitations

We evaluated 119 regions of interest (ROIs) from five patients, which included 60 epithelial (PanCK+) and 59 stromal segments (PanCK-). ROIs from responders had distinct expression signatures from non-responders for both the tumor and TME. Responders were more likely to have a dynamic change in expression after pembrolizumab than non-responders. A major limitation of this study was the number of patients evaluated.

Conclusion

For the first time, we have identified distinct expression signatures associated with response and resistance to IV pembrolizumab in NMIBCs. Further research with more patients and alternative checkpoint inhibitors is essential to validate our findings.

Patient Summary

We identify the molecular features of tumors associated with response to pembrolizumab for patients with BCG unresponsive NMIBCs.

From mucosal infection to successful cancer immunotherapy

The clinical management of advanced malignancies of the upper and lower urinary tract has been revolutionized with the advent of immune checkpoint blockers (ICBs). ICBs reinstate or bolster pre-existing immune responses while creating new T cell specificities. Immunogenic cancers, which tend to benefit more from immunotherapy than cold tumours, harbour tumour-specific neoantigens, often associated with a high tumour mutational burden, as well as CD8+ T cell infiltrates and ectopic lymphoid structures. The identification of beneficial non-self tumour antigens and natural adjuvants is the focus of current investigation. Moreover, growing evidence suggests that urinary or intestinal commensals, BCG and uropathogenic Escherichia coli influence long-term responses in patients with kidney or bladder cancer treated with ICBs. Bacteria infecting urothelium could be a prominent target for T follicular helper cells and B cells, linking innate and cognate CD8+ memory responses. In the urinary tract, commensal flora differ between healthy and tumoural mucosae. Although antibiotics can affect the prognosis of urinary tract malignancies, bacteria can have a major influence on cancer immunosurveillance. Beyond their role as biomarkers, immune responses against uropathogenic commensals could be harnessed for the design of future immunoadjuvants that can be advantageously combined with ICBs.

Leveraging cryoablation and checkpoint inhibitors for high-risk triple negative breast cancer

Breast cancer is the second most common cancer among women in the United States in which the standard of care treatment is surgery with adjunctive therapy. Cryoablation, which destroys the tumor using extremely cold temperatures while preserving the potential tumor antigens, is a promising alternative to surgical resection. It is less invasive, cosmetically appeasing, cost-effective, and capable of contributing to the abscopal effect - the immune response targeting potential distant metastasis. However, to maximize the immunologic benefit of cryoablation in biologically high-risk breast cancers, combination with therapies that enhance immune activation, such as immune checkpoint inhibitors (ICIs) may be necessary. This mini review describes the fundamentals of cryoablation and treatment with ICIs, as well as discuss the caveats in both strategies and current clinical trials aimed to improve this approach to benefit patients.

Immunotherapy in the Treatment of Localized Genitourinary Cancers

Importance

A true revolution in the management of advanced genitourinary cancers has occurred with the discovery and adoption of immunotherapy (IO). The therapeutic benefits of IO were recently observed not to be solely confined to patients with disseminated disease but also in select patients with localized and locally advanced genitourinary neoplasms.

Observations

KEYNOTE-057 demonstrated the benefit of pembrolizumab monotherapy for treating high-risk nonmuscle invasive bladder cancer unresponsive to bacillus Calmette-Guérin (BCG), resulting in recent US Food and Drug Administration approval. Furthermore, a current phase 3 trial (Checkmate274) demonstrated a disease-free survival benefit with the administration of adjuvant nivolumab vs placebo in muscle-invasive urothelial carcinoma after radical cystectomy. In addition, the recent highly publicized phase 3 KEYNOTE 564 trial demonstrated a recurrence-free survival benefit of adjuvant pembrolizumab in patients with high-risk localized/locally advanced kidney cancer.

Conclusions and Relevance

The adoption and integration of IO in the management of localized genitourinary cancers exhibiting aggressive phenotypes are becoming an emerging therapeutic paradigm. Clinical oncologists and scientists should become familiar with these trials and indications because they are likely to dramatically change our treatment strategies in the months and years to come.

Intravesical oncolytic virotherapy and immunotherapy for non-muscle-invasive bladder cancer mouse model

OBJECTIVES

To test if intravesical instillation of both an anti-programmed cell death protein 1 (PD-1) inhibitor and an oncolytic reovirus would demonstrate a greater effect than either treatment alone, as non-muscle-invasive bladder cancer that is refractory to intravesical bacillus Calmette-Guérin can be treated by systemic anti-PD-1 immunotherapy and we previously demonstrated improved overall survival (OS) with six once-weekly instillations of intravesical anti-PD-1 in a murine model.

MATERIALS AND METHODS

Using an orthotopic syngeneic C3H murine model of MBT2 urothelial bladder cancer, groups of 10 mice were compared between no treatment, intravesical anti-PD-1, intravesical oncolytic reovirus, or intravesical reovirus + anti-PD-1. A single intravesical treatment session was given. The primary outcome was OS, and the secondary outcomes included long-term immunity and tumour-immune profile.

RESULTS

With a median follow-up of 9 months, all mice that received no treatment died with a median survival of 41 days, while the comparison median OS was not reached for reovirus (hazard ratio [HR] 14.4, 95% confidence interval [CI] 3.9-32.6; P < 0.001), anti-PD-1 (HR 28.4, 95% CI 7.0-115.9; P < 0.001), and reovirus + anti-PD-1 (HR 28.4, 95% CI 7.0-115.9; P < 0.001). Monotherapy with anti-PD-1 or reovirus demonstrated no significant differences in survival (P = 0.067). Mass cytometry showed that reovirus + anti-PD-1 treatment enriched monocytes and decreased myeloid-derived suppressor cells, generating an immuno-responsive tumour microenvironment. Depletion of CD8+ T cells eliminated the survival advantage provided by the intravesical treatment.

CONCLUSIONS

Treatment of murine orthotopic bladder tumours with a single instillation of intravesical reovirus, anti-PD-1 antibody, or the combination confers superior survival compared to controls. Tumour-immune microenvironment differences indicated myeloid-derived suppressor cells and CD8+ T cells mediate the treatment response.

The bladder cancer immune micro-environment in the context of response to immune checkpoint inhibition

Treatment with neoadjuvant cisplatin-based chemotherapy followed by radical cystectomy is the default treatment for muscle-invasive bladder cancer (BC). However, with the encouraging results of immune checkpoint inhibitiors (ICI) directed against PD-1/PD-L1 and CTLA-4 in recent years, the treatment landscape of BC is rapidly changing. In addition, it is becoming clear that the effect of ICI is highly dependent on the interaction between tumor cells and the tumor immune micro-environment (TIME). Different immune cells are involved in an anti-tumor response in BC. Cytotoxic CD8+ T-cells are the main effector cells, aided by other immune cells including other T-cells, B-cells and pro-inflammatory macrophages. As part of the ongoing anti-tumor immune response, lymphocytes aggregate in clusters called tertiary lymphoid structures (TLS). Tumor mutational burden (TMB) and infiltration of immune cells into the tumor are both important factors for establishing an anti-tumor immune response. In contrast, transforming growth factor beta (TGF-β) signaling in cancer-associated fibroblasts (CAFs) prevents infiltration of lymphocytes and potentially has an immunosuppressive effect. In conclusion, the effect of ICI seems to be reliant on a combination of tumor-intrinsic and TIME-related parameters. More research is needed to fully understand the underlying biological mechanisms to further improve patient care.

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.

Neo-Adjuvant immunotherapies: Bladder cancer as a platform for drug development targeting mucosal immunity

Bacillus Calmette-Guerin (BCG) is a live attenuated Mycobacterium bovis strain, originally developed as a vaccine against tuberculosis. It is also the only bacterial cancer therapy approved by the US Food & Drug Administration for clinical use. BCG is delivered in the bladder, shortly after tumour resection, for patients with high-risk non-muscle invasive bladder cancer (NMIBC). Modulating mucosal immunity by exposing the urothelium to intravesical BCG has been the main therapeutic strategy for high-risk NMIBC over the last three decades. Thus, BCG provides a benchmark for the clinical development of bacteria-or other live attenuated pathogens-as cancer therapy. Currently, a myriad of immuno-oncology compounds is under clinical evaluation in BCG-unresponsive and BCG-naïve patients as an alternative therapy in the context of worldwide BCG shortages. For patients with non-metastatic muscle-invasive bladder cancer (MIBC), studies investigating neoadjuvant immunotherapy with either anti-PD-1/PD-L1 monoclonal antibodies in monotherapy or in combination with anti-CTLA-4 monoclonal antibodies have shown overall efficacy and acceptable safety profiles prior to radical cystectomy. Emerging clinical investigations are testing synergistic approaches by combining intravesical delivery of drugs with systemic immune checkpoint blockades in the neoadjuvant setting for patients with MIBC. Such novel strategy aims to prime a local anti-tumour immunity and reduce distant metastatic relapses by enhancing a systemic adaptive anti-tumour immune response. Here, we present and discuss some of the most promising clinical trials developing such novel therapeutic approaches.

Sequential intravesical gemcitabine and docetaxel therapy in patients with nonmuscle invasive bladder cancer: a systematic review and meta-analysis

PURPOSE OF REVIEW

Shortages in intravesical Bacillus Calmette-Guérin (BCG) immunotherapy represent a challenge in the management of high-risk nonmuscle invasive bladder cancer (HR-NMIBC). This study aimed to review the efficacy and safety of intravesical gemcitabine (GEM) and docetaxel (DOCE) for BCG-naive and unresponsive HR-NMIBC.

RECENT FINDINGS

We identified six studies eligible for quantitative analysis through a systematic search according to the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA) statement. In the two studies in the BCG-naive setting, 1-year and 2-year pooled recurrence-free survival (RFS) were 86 and 84%, respectively. In the two studies in the BCG unresponsive setting, 6-month, 1-year and 2-year pooled high-grade recurrence-free survival (HG-RFS) were 80, 66 and 51%, respectively. Cumulative data from four studies revealed that 2.3% of patients could not complete induction therapy and 6.9% experienced treatment delay or dose reduction due to adverse events.

SUMMARY

Despite the preliminary data and based on a small sample size, intravesical GEM/DOCE therapy is a highly promising combination yielding an effective and well tolerated alternative to BCG when indicated. Further large, well designed comparative studies with BCG are needed.

Novel technologies for applying immune checkpoint blockers

Cancer cells develop several ways to subdue the immune system among others via upregulation of inhibitory immune checkpoint (ICP) proteins. These ICPs paralyze immune effector cells and thereby enable unfettered tumor growth. Monoclonal antibodies (mAbs) that block ICPs can prevent immune exhaustion. Due to their outstanding effects, mAbs revolutionized the field of cancer immunotherapy. However, current ICP therapy regimens suffer from issues related to systemic administration of mAbs, including the onset of immune related adverse events, poor pharmacokinetics, limited tumor accessibility and immunogenicity. These drawbacks and new insights on spatiality prompted the exploration of novel administration routes for mAbs for instance peritumoral delivery. Moreover, novel ICP drug classes that are adept to novel delivery technologies were developed to circumvent the drawbacks of mAbs. We therefore review the state-of-the-art and novel delivery strategies of ICP drugs.

Novel Therapies for High-Risk Non-Muscle Invasive Bladder Cancer

PURPOSE OF REVIEW

The treatment options for high-risk non-muscle invasive bladder cancer (NMIBC), particularly following BCG, remain limited. We highlight recent, promising therapies for high-risk NMIBC.

RECENT FINDINGS

Several therapies utilizing different mechanisms of action have demonstrated favorable results in the BCG-naïve and BCG-unresponsive settings. These treatments include intravenous and intravesical immunotherapy, viral- and bacterial-based intravesical therapies, combination intravesical chemotherapy regimens, and novel intravesical chemotherapy administration. Overall, the efficacy and tolerability of emerging treatments for NMIBC appear promising and provide potential alternatives to radical cystectomy. As the landscape of managing BCG-unresponsive disease evolves, clinical trials will explore future options and determine effective alternatives.

The Efficacy and Safety of Tislelizumab as Adjuvant Treatment for Advanced or Metastatic Bladder Cancer in People Living With HIV: A Retrospective Multi-Center Study

BACKGROUND

People living with HIV (PLWH) have a worse prognosis than the general population. Locally advanced or metastatic bladder cancer (BCa) in PLWH has gradually been increasing in recent years. Immune checkpoint inhibitors can improve antitumor activity in the general population, but relevant data in PLWH are unknown. We thus evaluated the efficacy and safety of tislelizumab in PLWH with locally advanced or metastatic BCa.

METHODS

This retrospective study included 24 patients with locally advanced or metastatic BCa, both HIV positive or negative who underwent tislelizumab treatment (200 mg i.v. every 3 weeks, Q3W) from the multi-centers between December 2019 and March 2022. Demographic details, clinical data, and cancer status were collected. The overall survival (OS), progression-free survival (PFS), overall response rate (ORR), disease control rate (DCR), clinical benefit rate (CBR), and treatment-related adverse events (TRAEs) were recorded and evaluated.

RESULTS

A total of 24 individuals were chosen for this study, 10 had HIV and the other 14 did not. The median OS in the HIV-negative group was 62.3 (95% CI, 52.6 to 72.2) was no longer than that of the PLWH group 41.9 (95% CI, 32.9 to 51.0) weeks (HR .7, [95% CI, .17 to 3.30], P = .70). Furthermore, the median PFS in the HIV-negative group was 50.0 (95% CI, 36.2 to 63.9) was also no longer than that of the PLWH group 35.9 (95% CI, 25.5 to 46.3) (HR, 1.34, [95% CI, .38 to 4.69], P = .63). Of 24 patients, treatment-related adverse events, grade 3 or 4 occurred in 2 in the PLWH group and 3 in the HIV-negative group.

CONCLUSION

This retrospective multi-center study suggested that tislelizumab may provide encouraging antitumor activity and could be generally well tolerated. In this retrospective analysis of patients with locally advanced or metastatic BCa, it seems that PLWH may have similar overall and progression-free survival compared to HIV-negative cases.

Tumor-Microenvironment Characterization of the MB49 Non-Muscle-Invasive Bladder-Cancer Orthotopic Model towards New Therapeutic Strategies

Bacillus Calmette-Guérin (BCG) instillations for the treatment of non-muscle-invasive bladder cancer patients can result in significant side effects and treatment failure. Immune checkpoint blockade and/or decreasing tumor-infiltrating myeloid suppressor cells may be alternative or complementary treatments. Here, we have characterized immune cell infiltration and chemoattractant molecules in mouse orthotopic MB49 bladder tumors. Our data show a 100-fold increase in CD45⁺ immune cells from day 5 to day 9 tumors including T cells and mainly myeloid cells. Both monocytic myeloid-derived suppressor-cells (M-MDSC) and polymorphonuclear (PMN)-MDSC were strongly increased in day 9 tumors, with PMN-MDSC representing ca. 70% of the myeloid cells in day 12 tumors, while tumor associated macrophages (TAM) were only modestly increased. The kinetic of PD-L1 tumor expression correlated with published data from patients with PD-L1 expressing bladder tumors and with efficacy of anti-PD-1 treatment, further validating the orthotopic MB49 bladder-tumor model as suitable for designing novel therapeutic strategies. Comparison of chemoattractants expression during MB49 bladder tumors grow highlighted CCL8 and CCL12 (CCR2-ligands), CCL9 and CCL6 (CCR-1-ligands), CXCL2 and CXCL5 (CXCR2-ligands), CXCL12 (CXCR4-ligand) and antagonist of C5/C5a as potential targets to decrease myeloid suppressive cells. Data obtained with a single CCR2 inhibitor however showed that the complex chemokine crosstalk would require targeting multiple chemokines for anti-tumor efficacy.