Integrating novel immunotherapeutic approaches in organ-preserving therapies for bladder cancer

Bladder cancer (BC) is a prevalent malignancy with significant morbidity and mortality. Over the years, the landscape of bladder cancer treatment has witnessed notable advancements, particularly in the realm of immunotherapy. Immunotherapy has emerged as a promising adjunct to organ-preserving approaches, harnessing the immune system's potential to target and eliminate cancer cells. Organ preservation strategies offer viable alternatives to radical cystectomy to avoid the morbidities associated with radical surgery, as well as to respond to the needs of patients unfit for or who have refused surgery. However, the challenge lies in achieving durable disease control while minimizing treatment-related toxicities. This review highlights the significance of immune checkpoint inhibitors, such as anti-programmed cell death 1 (PD-1)/programmed cell death 1 ligand 1 (PD-L1) antibodies, in the treatment of localized bladder cancer. The clinical efficacy of immune checkpoint inhibitors, as both neoadjuvant and adjuvant therapies in combination with radiation or chemotherapy, is discussed. Moreover, the potential of immunotherapies beyond immune checkpoint inhibition, including combinations with bacillus Calmette-Guérin (BCG) instillations and/or investigational gene therapies, is explored. Furthermore, the predictive value of the tumour immune microenvironment for the success of these strategies is examined. Understanding the complex interplay between tumour immunity and therapeutic interventions can aid in identifying predictive biomarkers and tailoring personalized treatment strategies. Further research and clinical trials are warranted to optimize the use of immunotherapy in conjunction with organ-preserving therapies, potentially leading to enhanced patient outcomes and quality of life.

Bladder-sparing treatment for muscle-invasive bladder carcinoma using immune checkpoint inhibitors

Multimodal bladder preservation therapy is already an alternative for patients with muscle-invasive bladder cancer (MIBC) who are unable or unwilling to undergo radical cystectomy. Various bladder-preserving strategies that employ immune checkpoint inhibitors (ICIs) for MIBC have been investigated. There are three common modes of ICI-based bladder preservation therapy, of which the most studied is ICIs combined with chemoradiotherapy. The bladder-preserving strategy of ICIs combined with radiation has been investigated in patients who poorly tolerate chemotherapy. ICIs combined with chemotherapy have also been explored in patients who responded to neoadjuvant therapy with a clinical complete response. All the above-described strategies have shown promising efficacy and manageable safety profiles. However, the value of programmed death-ligand 1 (PD-L1) expression, tumor mutation burden and gene alterations for predicting the efficacy of immune-based bladder preservation therapy is still controversial. There remain some challenges for immune-based bladder preservation therapy, and large-sample randomized trials are needed.

Muscle invasive bladder cancer: where is the field headed?

INTRODUCTION

The standard treatment for muscle-invasive bladder cancer (MIBC) is cisplatin-based neoadjuvant chemotherapy (NAC) followed by radical cystectomy or upfront radical cystectomy for cisplatin-ineligible patients. In those who are ineligible for or refuse radical cystectomy, trimodal therapy with chemoradiation is offered. However, with the success of immune checkpoint inhibitors (ICI) and antibody-drug conjugates such as enfortumab vedotin in the metastatic setting, several trials are implementing these drugs in the neoadjuvant setting for cisplatin ineligible patients. Indeed, nivolumab is approved as adjuvant therapy for high-risk muscle-invasive urothelial carcinoma.

AREAS COVERED

Clinical trials using ICI, ICI/ICI, and ICI/chemotherapy combination therapies in the perioperative setting have been completed. These clinical trials have demonstrated that neoadjuvant ICI are safe and have encouraging pCR, making them promising treatment options. Neoadjuvant enfortumab vedotin alone and in combination with pembrolizumab is also being studied, and preliminarily to have promising activity. ICI is also being combined with radiation therapy (RT) and early data indicate that ICI combined with RT or chemo-RT may be safe with promising activity.

EXPERT OPINION

Biomarkers are urgently needed to identify appropriate treatment options for individual patients. The use of novel treatment approaches and biomarkers will help shape the future of precision therapy for MIBC and enable bladder preservation.

Immunotherapy in urothelial cancer: current status and future directions

INTRODUCTION

Since 2016, the progressive use of immune checkpoint inhibitors (ICIs) starting from second-line treatment has led to an improvement in overall survival in locally advanced and metastatic urothelial cancer (UC). Clinical trials are underway testing the role of ICIs since the first stages of the disease, alone or in combination with standard therapies.

AREAS COVERED

This review summarizes the current updated evidence regarding the role of ICIs in the different stages of UC, the ongoing clinical trials exploring the potential benefit of immunotherapy alone or in combination with standard-of-care therapies, as well as the promising association of ICIs with antibody-drug conjugates (ADCs).

EXPERT OPINION

In the first-line setting, ICIs alone in platinum-unfit patients have shown unconvincing results; the ongoing EV-302 trial will probably suggest enfortumab vedotin plus pembrolizumab as a new effective option. The optimal duration of maintenance immunotherapy is still to be determined, finding a balance with the risk-benefit profile. The clinical benefit of ICIs as second-line treatment is limited to a subset of patients that cannot be definitively established yet. In the next 5 years, a lot of new ADCs will likely emerge for the treatment of UC.

Real-world retrospective study of immune checkpoint inhibitors in combination with radiotherapy or chemoradiotherapy as a bladder-sparing treatment strategy for muscle-invasive bladder urothelial cancer

Background

Recent developments in MIBC treatment suggest good efficacy of bladder sparing treatment combined with immune checkpoint inhibitor. However, there is no standard treatment mode. A retrospective analysis was conducted to reveal the efficacy and safety of PD-1 inhibitor in combination with radiotherapy or chemoradiotherapy.

Methods

We retrospectively analyzed 25 patients with MIBC T2-T3N0M0 disease who were unfit or unwilling to undergo RC. These patients underwent the maximum TURBT followed by PD-1 inhibitor (Tislelizumab or Toripalimab) in combination with radiotherapy or chemoradiotherapy (gemcitabine plus cisplatin) between April 2020 and May 2022. The primary outcome was clinical complete response (cCR) rate. The secondary outcomes were disease free survival (DFS) and overall survival (OS).

Results

Revised: Of 25 patients, 22 were T2 (88%), while 3 were T3 (12%). The median age is 65 years (51-80). Twenty-one patients had programmed cell death ligand 1 (PD-L1) combined positive score (CPS) of 1 or more, and 4 patients had CPS<1 or unknown. Sixteen patients received chemoradiotherapy. Tislelizumab and Toripalimab were administered to 19 and 6 patients, respectively. The median number of cycles of immunotherapy was 8. Twenty-three patients (92%) achieved cCR. Following a median of 13 months of follow-up (range, 5-34 months), 1-year DFS and OS rate were 92% and 96%, respectively. In the univariate analysis, T stage significantly influenced OS and ORR, and efficacy evaluation significantly influenced OS, DFS, and ORR. The expression of PD-L1 and chemotherapy had no effect on prognosis. In the multivariate analysis, no independent prognostic factors were found. Grade 3 or 4 adverse events (AE) were reported in 35.7% patients.

Conclusions

Bladder sparing therapy with PD-1 inhibitor in combination with radiotherapy or chemoradiotherapy is feasible, safe, and highly effective for patients who were unfit or unwilling to undergo RC.

Multidisciplinary Management and Radiotherapy Recommendations for Clinically and Pathologically Node-positive Bladder Cancer

There are limited data regarding the optimal management of patients with pelvic node-positive, but non-metastatic, bladder cancer. Increasing data demonstrate that this is a distinct clinical entity with outcomes bridging between bladder-confined muscle-invasive bladder cancer and metastatic advanced bladder cancer. Guidelines and staging systems have formalized the need to incorporate the unique considerations of management of pelvic node-positive bladder cancer. However, there remains an absence of a definite standard of care. Treatment options include systemic therapy alone, neoadjuvant chemotherapy followed by radical cystectomy, or bladder-preserving trimodality therapy. Furthermore, ongoing studies aim to determine the benefit of incorporating immunotherapy into these treatment paradigms. In this review article, we will discuss the key considerations for management of patients with pelvic node-positive bladder cancer.

Combination of radiation and immunotherapy in the treatment of genitourinary malignancies: A systematic review and meta-analysis

BACKGROUND

Due to possible synergistic effects, the combination of radiation therapy (RT) and immune checkpoint inhibitors (ICI) represents an interesting therapeutic option. An increasing number of clinical trials are ongoing to investigate this combination in genitourinary malignancies and the first results are available.

OBJECTIVES

To review and summarize available data on the combination of RT and ICI in genitourinary malignancies and update the evidence for this potential therapeutic approach.

EVIDENCE ACQUISITION

A study protocol was registered in the PROSPERO-Database. Terms of search were prostate cancer, bladder cancer, renal cell carcinoma, penile cancer, testicular cancer, radiotherapy, and immunotherapy in multiple literature databases and study registers. Clinical studies reporting on the combination treatment of RT and ICI were included. A systematic review of ongoing trials according to the PRISMA statement and a meta-analysis of available trials were performed.

EVIDENCE SYNTHESIS

Overall, 43 studies met the inclusion criteria examining the therapeutic effect of combined RT and ICI. For bladder cancer, renal cell carcinoma, prostate cancer, and penile cancer 28, 9, 5, and 1 trial could be identified, respectively. No study was found for testicular cancer. Three phases III trials were identified, all other trials were phase I or II. Twelve studies have been completed so far. The meta-analysis of available data indicates comparable toxicity of RT plus ICI vs. ICI alone for grade 3/4 AEs. Mature efficacy data is limited with interesting early results.

CONCLUSION

This article reviews the clinical trial landscape investigating RT and ICI in genitourinary malignancies. It provides an overview of ongoing trials and discusses available results. Actual data regarding efficacy is limited, while toxicities seem comparable to ICI alone. Especially in bladder and kidney cancer, further trial results might impact on the clinical use of the combination therapy.

Advances in the management of urothelial carcinoma: is immunotherapy the answer?

Introduction: Urothelial carcinoma (UC) is the second most common malignancy of the genitourinary system in the US, but mortality rate has not significantly improved despite advances in therapy. Over the past few years, the treatment landscape of non-muscle-invasive, muscle-invasive and metastatic UC (mUC) has evolved with the advent of immunotherapy.Areas covered: This paper summarizes current data and ongoing research into the use of immune checkpoint inhibitors (ICIs) in various settings of UC, including as maintenance therapy in chemotherapy-responsive mUC (with recent approval for avelumab in this setting) and as neoadjuvant and adjuvant therapies in localized and non-muscle-invasive disease. In addition, the authors review the combination of ICIs with chemotherapy, radiation and targeted therapies in an effort to increase response durability and efficacy.Expert opinion: While there has been a rapid expansion in clinical trials, platinum-based chemotherapy remains standard treatment in perioperative and first-line metastatic UC. The identification of biomarkers that can identify patients who will respond to ICIs has yielded conflicting results and has been largely non-generalizable to clinical practice. Further research into novel strategies and combinations with ICIs is needed to better characterize the role of immunotherapy in UC.