LBA24 CG0070, AN ONCOLYTIC ADENOVIRUS, FOR BCG-UNRESPONSIVE NON-MUSCLE-INVASIVE BLADDER CANCER (NMIBC): 12 MONTH INTERIM RESULTS FROM A MULTICENTER PHASE II TRIAL

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.

Novel and emerging approaches in the management of non-muscle invasive urothelial carcinoma

Non-muscle invasive bladder cancer (NMIBC) has traditionally been managed with transurethral resection followed by intravesical chemotherapy and/or bacillus Calmette-Guerin (BCG) in a risk-adapted manner. These tumors commonly recur and can progress potentially to lethal muscle invasive disease. A major unmet need in the field of NMIBC is bladder preserving therapy for recurrent high-grade NMIBC after adequate intravesical BCG therapy. The current gold standard treatment for these BCG-unresponsive patients is radical cystectomy, which is associated with considerable morbidity and mortality, particularly in older and frailer patients. It is therefore critical to provide alternative treatment options with acceptable oncological outcomes. In this review we explore novel bladder-sparing treatment options including combination intravesical therapy, enhanced instillation methods, immunotherapy, gene therapy, targeted therapy, photodynamic therapy and BCG variants across the spectrum of NMIBC disease states, ranging from low grade BCG-naïve patients through to high-grade BCG-unresponsive NMIBC.

The current landscape of salvage therapies for patients with bacillus Calmette-Guérin unresponsive nonmuscle invasive bladder cancer

PURPOSE OF REVIEW

Although radical cystectomy represents the gold standard treatment for patients with high-risk nonmuscle invasive bladder cancer (NMIBC) whose disease does not respond to bacillus Calmette-Guérin (BCG), many patients are unable or unwilling to undergo surgery. The need remains for effective bladder-preserving therapies. This review aims to describe existing treatments, contemporary research in this field and ongoing trials of salvage therapies for patients with BCG-unresponsive NMIBC.

RECENT FINDINGS

Intravesical chemotherapy has been utilized frequently in this setting. Emerging data on combination regimens such as intravesical gemcitabine and docetaxel and intravesical cabazitaxel, gemcitabine and cisplatin are promising; nevertheless, larger, prospective trials are needed. Meanwhile, the intravenous checkpoint inhibitor pembrolizumab was recently FDA-approved for patients BCG-unresponsive NMIBC. Encouraging clinical trial results for intravesical nadofaragene firadenovec, oportuzumab monatox and ALT-803 + BCG have been released, while data from trials of other treatment strategies, including novel chemotherapy and drug delivery, augmented BCG immunotherapy, adenoviral and gene therapy, targeted therapy, and combination systemic immunotherapy with intravesical agents, are eagerly awaited.

SUMMARY

Several novel salvage therapies offer promise for patients with BCG-unresponsive NMIBC. Patient selection, efficacy, safety, cost and ease of administration must be carefully considered to determine the optimal treatment approach.