Diminished Short-Term Efficacy of Reduced-Dose Induction BCG in the Treatment of Non-Muscle Invasive Bladder Cancer

The ongoing Bacillus Calmette-Guérin (BCG) shortage has created challenges for the treatment of non-muscle invasive bladder cancer (NMIBCa). Our objective was to evaluate the efficacy of reduced-dose induction BCG (RD-iBCG) compared to full-dose induction BCG (FD-iBCG) regarding recurrence rates. We hypothesized that patients receiving RD-iBCG may recur at a higher rate compared to those who received FD-iBCG therapy. A retrospective review of all patients with NMIBCa treated with intravesical therapy at our institution between 2015-2020 was conducted. Inclusion criteria consisted of having a diagnosis of AUA intermediate or high-risk NMIBCa with an indication for a six-week induction course of FD or RD-BCG with at least 1 year of documented follow up. The data were censored at one year. Propensity score matching for age, sex, tumor pathology, and initial vs. recurrent disease was performed. The primary endpoint was bladder cancer recurrence, reported as recurrence-free survival. A total of 254 patients were reviewed for this study. Our final cohort was 139 patients after exclusion. Thirty-nine percent of patients had HGT1 disease. 38.6% of patients receiving RD-BCG developed a recurrence of bladder cancer within a one-year follow-up as compared to 33.7% of patients receiving FD therapy. After propensity matching, this value remained statistically significant (p = 0.03). In conclusion, RD-iBCG for NMIBCa is associated with a significantly greater risk of recurrence than full-dose induction therapy, suggesting that RD-iBCG may not be equivalent or non-inferior to full-dose administration in the short term.

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.

Adjuvant therapies for non-muscle-invasive bladder cancer: advances during BCG shortage

Non-muscle-invasive bladder cancer (NMIBC) represents a significant global therapeutic challenge, particularly in the era of Bacillus Calmette-Guérin (BCG) shortage. High-risk NMIBC can progress to muscle invasive or metastatic disease in 25% of patients. Optimal treatment selection, according to risk stratification, is imperative. International guidelines slightly differ in their categorisation of low, intermediate and high-risk NMIBC. Nonetheless, a single post-operative instillation of chemotherapy with Mitomycin C (MMC) or Gemcitabine improves relapse-free survival (RFS) in low-risk NMIBC. Induction and maintenance intravesical BCG remains the historical gold standard for patients with intermediate or high-risk NMIBC. However, clinicians may be forced to consider alternatives given the current BCG shortage. Both intravesical MMC and Gemcitabine have been associated with similar efficacy to BCG, albeit in smaller studies. MMC may also be manipulated using a variety of methods to potentiate its effects. BCG treatment delivery may also be modified without affecting efficacy through dose reduction and abbreviation or omission of maintenance therapy. Preliminary data also highlight that directly proceeding to radical cystectomy may not adversely affect long-term quality of life measures. Access to new systemic and intravesical therapies must be prioritised for patients with BCG recurrent or unresponsive disease. When used in conjunction with molecularly defined biomarkers, these agents herald the potential for improved survival outcomes and alleviation of the current BCG shortage.

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.

Checkpoint inhibitors in BCG-unresponsive nonmuscle invasive bladder cancer: can they help spare the bladder?

Intravesical BCG therapy has been for years, the standard of care in nonmuscle-invasive bladder cancer. But upon recurrence/relapse, radical cystectomy is imposed, due to the paucity of other therapeutic options. Immunotherapy has been revolutionizing cancer treatment, and its indications continue to broaden. It has been approved for the treatment of advanced urothelial cancer of the bladder, mainly as a second-line therapy. Its activity is being studied in nonmuscle-invasive bladder cancer that is not responsive to BCG; we herein report the trials investigating these checkpoint inhibitors (pembrolizumab, nivolumab, atezolizumab, durvalumab and avelumab) in this particular setting.

New immunotherapies for high-risk non-muscle invasive bladder cancer: Current state and future perspectives

BACKGROUND

The standard treatment for high-risk non-muscle invasive bladder tumors (NMIBT) is transurethral resection of the bladder and BCG instillations. However, responses are limited, and new therapeutic alternatives for these patients are required. The results of checkpoint inhibitors in advanced tumors have led to interest in the use of these molecules in NMIBT.

METHODS

We conducted a search on PubMed using the terms «bladder cancer» and «check point inhibitors». We have used the search engines clinicaltrials.gov and clinicaltrialsregister.eu for the search of clinical trials.

RESULTS

There are currently 5 trials in progress on BCG untreated patients. There are no results available. As for BCG non-responders, there are 15 ongoing trials, two of them with preliminary results: Keynote 057, with promising results with pembrolizumab, which has led the FDA to approve its use in January 2020, and SWOG S1605, which has shown similar results with atezolizumab. Other trials are using intravesical administration of these drugs, which is an attractive option if it is effective for cancer control.

CONCLUSIONS

Checkpoint inhibitors offer a new possibility for patients who do not respond to BCG. These will probably be used in the future for previously BCG untreated patients. Preliminary data from clinical trials show promising results. A good understanding of these molecules by urologists and the creation of multidisciplinary teams are crucial in order to offer the best therapeutic alternatives to these patients.