Immunotherapy Combined With Radiation Therapy for Genitourinary Malignancies

Randomized Phase II Study Evaluating the Addition of Pembrolizumab to Radium-223 in Metastatic Castration-resistant Prostate Cancer

The checkpoint immunotherapeutic pembrolizumab induces responses in a small minority of patients with metastatic castration-resistant prostate cancer (mCRPC). Radium-223 (R223) may increase immunogenicity of bone metastases and increase pembrolizumab (P) activity. In a randomized phase II study, we assessed the effect of R223+P compared with R223 on tumor immune infiltration, safety, and clinical outcomes in patients with mCRPC. The primary endpoint was differences in CD4+ and CD8+ T-cell infiltrate in 8-week versus baseline bone metastasis biopsies; secondary endpoints were safety, radiographic progression-free survival (rPFS), and overall survival (OS). Of the 42 treated patients (29 R223+P, 13 R223), 18 R223+P and 8 R223 patients had evaluable paired tumor biopsies. Median fold-change of CD4+ T cells was -0.7 (range: -9.3 to 4.7) with R223+P and 0.1 (-11.1 to 3.7) with R223 (P = 0.66); for CD8+ T cells, median fold-change was -0.6 (-7.4 to 5.3) with R223+P and -1.3 (-3.1 to 4.8) with R223 (P = 0.66). Median rPFS and OS was 6.1 (95% confidence interval: 2.7-11.0) and 16.9 months [12.7-not reached (NR)], respectively, with R223+P and 5.7 (2.6-NR) and 16.0 (9.0-NR), respectively, with R223. Although R223+P was well tolerated with no unexpected toxicity, the combination did not improve efficacy. High-dimensional flow cytometry demonstrated minimal immune modulation with R223, whereas R223+P induced CTLA-4 expression on circulating CD4+ T cells. Clinical responders possessed lower circulating frequencies of Ki67+ T and myeloid cells at baseline and higher circulating frequencies of TIM-3+ T and myeloid cells by week 9. Although R223+P did not induce T-cell infiltration into the tumor microenvironment, exhaustion of induced peripheral T-cell immune responses may dampen the combination's clinical activity.

Regenerating murine CD8+ lung tissue resident memory T cells after targeted radiation exposure

Radiation exposure occurs during medical procedures, nuclear accidents, or spaceflight, making effective medical countermeasures a public health priority. Naïve T cells are highly sensitive to radiation-induced depletion, although their numbers recover with time. Circulating memory CD8+ T cells are also depleted by radiation; however, their numbers do not recover. Critically, the impact of radiation exposure on tissue-resident memory T cells (TRM) remains unknown. Here, we found that sublethal thorax-targeted radiation resulted in the rapid and prolonged numerical decline of influenza A virus (IAV)-specific lung TRM in mice, but no decline in antigen-matched circulating memory T cells. Prolonged loss of lung TRM was associated with decreased heterosubtypic immunity. Importantly, boosting with IAV-epitope expressing pathogens that replicate in the lungs or peripheral tissues or with a peripherally administered mRNA vaccine regenerated lung TRM that was derived largely from circulating memory CD8+ T cells. Designing effective vaccination strategies to regenerate TRM will be important in combating the immunological effects of radiation exposure.

The role of radiotherapy in immunotherapy strategies in the central nervous system

The clinical efficacy and relative tolerability of adverse effects of immune checkpoint immunotherapy have led to its increasingly routine use in the management of multiple advanced solid malignancies. Radiation therapy (RT) is well-known to have both local and distant immunomodulatory effects, which has led to extensive investigation into the synergism of these 2 therapies. While the central nervous system (CNS) has historically been thought to be a sanctuary site, well-protected by the blood-brain barrier from the effects of immunotherapy, over the last several years studies have shown the benefits of these drugs, particularly in metastatic disease involving the CNS. This review explores current progress and the future of combination therapy with immune checkpoint inhibitors and RT.

Bladder sparing by short-course radiotherapy combined with toripalimab in high-risk/extremely high-risk non-muscle invasive bladder cancer (HOPE-04): study protocol for a single-arm, prospective, phase II trial

INTRODUCTION

Radical cystectomy remains the standard treatment for intravesical Bacille Calmette-Guerin (BCG) unresponsive non-muscle invasive bladder cancer (NMIBC) because potential bladder-preserving therapies are not well established. Combination of radiotherapy with programmed death-1 (PD-1) antibody may offer an optional bladder preservation treatment for high-risk/extremely high risk NMIBC. Hence, the current study aims to investigate the safety and efficacy of short-course radiotherapy (5×5 Gy) and toripalimab (PD-1 antibody) as a novel bladder sparing treatment in this population.

METHODS AND ANALYSIS

HOPE-04 is an open-label, single-arm, phase II study, designed to evaluate the safety and efficacy of short-course radiotherapy and toripalimab in patients with high-risk/extremely high risk NMIBC. Fifty-five patients with pathological and imaging diagnosed NMIBC with or without BCG treatment will be recruited. Radiotherapy of 5×5 Gy will be given to the whole bladder followed by a focal tumour bed boost and concomitant administration of toripalimab of 240 mg intravenous infusion every 21 days for 12 cycles (about 1 year). The primary endpoints are disease-free survival and safety. The secondary endpoint is overall survival. Additional indicators include implementation rate of salvage surgery and quality of life.

ETHICS AND DISSEMINATION

This trial has been approved by the Ethics Committee of West China Hospital, Sichuan University. Trial findings will be disseminated via peer reviewed journals and conference presentations.

TRIAL REGISTRATION NUMBER

Chinese Ethics Committee of Registering Clinical Trials (ChiCTR2200059970).

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.

Survival in Metastatic Renal Cell Carcinoma Treated With Immunotherapy and Stereotactic Radiation Therapy or Immunotherapy Alone: A National Cancer Database Analysis

Purpose

Immunotherapy (IO) has significantly improved outcomes in metastatic renal cell carcinoma (mRCC). Preclinical evidence suggests that responses to IO may be potentiated via immunomodulatory effects of stereotactic radiation therapy (SRT). We hypothesized that clinical outcomes from the National Cancer Database (NCDB) would demonstrate improved overall survival (OS) in patients with mRCC receiving IO + SRT versus IO alone.

Methods and Materials

Patients with mRCC receiving first-line IO ± SRT were identified from the NCDB. Conventional radiation therapy was allowed in the IO alone cohort. The primary endpoint was OS stratified by the receipt of SRT (IO + SRT vs IO alone). Secondary endpoints included OS stratified by the presence of brain metastases (BM) and timing of SRT (before or after IO). Survival was estimated using Kaplan-Meier methodology and compared via the log-rank test.

Results

Of 644 eligible patients, 63 (9.8%) received IO + SRT, and 581 (90.2%) received IO alone. Median follow-up time was 17.7 months (range, 2-24 months). Sites treated with SRT included the brain (71.4%), lung/chest (7.9%), bones (7.9%), spine (6.3%), and other (6.3%). OS was 74.4% versus 65.0% at 1 year and 71.0% versus 59.4% at 2 years for the IO + SRT and IO alone groups, respectively, although this difference did not reach statistical significance (log-rank P = .1077). In patients with BM, however, 1-year OS (73.0% vs 54.7%) and 2-year OS (70.8% vs 51.4%) was significantly higher in those receiving IO + SRT versus IO alone, respectively (pairwise P = .0261). Timing of SRT (before or after IO) did not influence OS (log-rank P = .3185).

Conclusions

Patients with BM secondary to mRCC had prolonged OS with the addition of SRT to IO. Factors such as International mRCC Database Consortium risk stratification, oligometastatic tumor burden, SRT dose/fractionation, and utilization of doublet therapy should be considered in future analyses to better identify patients who may benefit from combined IO + SRT. Further prospective studies are warranted.

Emerging RNA-Based Therapeutic and Diagnostic Options: Recent Advances and Future Challenges in Genitourinary Cancers

Renal cell carcinoma, bladder cancer, and prostate cancer are the most widespread genitourinary tumors. Their treatment and diagnosis have significantly evolved over recent years, due to an increasing understanding of oncogenic factors and the molecular mechanisms involved. Using sophisticated genome sequencing technologies, the non-coding RNAs, such as microRNAs, long non-coding RNAs, and circular RNAs, have all been implicated in the occurrence and progression of genitourinary cancers. Interestingly, DNA, protein, and RNA interactions with lncRNAs and other biological macromolecules drive some of these cancer phenotypes. Studies on the molecular mechanisms of lncRNAs have identified new functional markers that could be potentially useful as biomarkers for effective diagnosis and/or as targets for therapeutic intervention. This review focuses on the mechanisms underlying abnormal lncRNA expression in genitourinary tumors and discusses their role in diagnostics, prognosis, and treatment.

Immune Checkpoint Inhibitors for Solid Tumors in the Adjuvant Setting: Current Progress, Future Directions, and Role in Transplant Oncology

The rationale for administering immune checkpoint inhibitors (ICIs) in the adjuvant setting is to eradicate micro-metastases and, ultimately, prolong survival. Thus far, clinical trials have demonstrated that 1-year adjuvant courses of ICIs reduce the risk of recurrence in melanoma, urothelial cancer, renal cell carcinoma, non-small cell lung cancer, and esophageal and gastroesophageal junction cancers. Overall survival benefit has been shown in melanoma while survival data are still not mature in other malignancies. Emerging data also show the feasibility of utilizing ICIs in the peri-transplant setting for hepatobiliary malignancies. While ICIs are generally well-tolerated, the development of chronic immune-related adverse events, typically endocrinopathies or neurotoxicities, as well as delayed immune-related adverse events, warrants further scrutiny regarding the optimal duration of adjuvant therapy and requires a thorough risk-benefit determination. The advent of blood-based, dynamic biomarkers such as circulating tumor DNA (ctDNA) can help detect minimal residual disease and identify the subset of patients who would likely benefit from adjuvant treatment. In addition, the characterization of tumor-infiltrating lymphocytes, neutrophil-to-lymphocyte ratio, and ctDNA-adjusted blood tumor mutation burden (bTMB) has also shown promise in predicting response to immunotherapy. Until additional, prospective studies delineate the magnitude of overall survival benefit and validate the use of predictive biomarkers, a tailored, patient-centered approach to adjuvant ICIs that includes extensive patient counseling on potentially irreversible adverse effects should be routinely incorporated into clinical practice.

An abscopal effect in a gastric cancer patient treated with combined chemoimmunotherapy and palliative radiotherapy

The prognosis of advanced gastric cancer remains poor. Palliative radiotherapy has been utilized to palliate bleeding in unresectable gastric cancer. Recent studies have described that a systemic immune response may be induced by local radiotherapy to the primary tumor lesion. Here we report a rare case of an abscopal effect in a patient with inoperable gastric cancer combined with tumor hemorrhage. A short course of radiotherapy was performed to palliate bleeding; additionally, the patient was treated with chemotherapy and immunotherapy. Complete response was achieved in the lung metastasis lesion. The observed abscopal effect suggests that there may be a synergistic effect between immunotherapy and radiotherapy. This case report supports the combination of immunotherapy and radiotherapy in patients with advanced gastric cancer.

Immunotherapy approaches for the treatment of diffuse midline gliomas

Diffuse midline gliomas (DMG) are a highly aggressive and universally fatal subgroup of pediatric tumors responsible for the majority of childhood brain tumor deaths. Median overall survival is less than 12 months with a 90% mortality rate at 2 years from diagnosis. Research into the underlying tumor biology and numerous clinical trials have done little to change the invariably poor prognosis. Continued development of novel, efficacious therapeutic options for DMGs remains a critically important area of active investigation. Given that DMGs are not amenable to surgical resection, have only limited response to radiation, and are refractory to traditional chemotherapy, immunotherapy has emerged as a promising alternative treatment modality. This review summarizes the various immunotherapy-based treatments for DMG as well as their specific limitations. We explore the use of cell-based therapies, oncolytic virotherapy or immunovirotherapy, immune checkpoint inhibition, and immunomodulatory vaccination strategies, and highlight the recent clinical success of anti-GD2 CAR-T therapy in diffuse intrinsic pontine glioma (DIPG) patients. Finally, we address the challenges faced in translating preclinical and early phase clinical trial data into effective standardized treatment for DMG patients.

Biological Mechanisms to Reduce Radioresistance and Increase the Efficacy of Radiotherapy: State of the Art

Cancer treatment with ionizing radiation (IR) is a well-established and effective clinical method to fight different types of tumors and is a palliative treatment to cure metastatic stages. Approximately half of all cancer patients undergo radiotherapy (RT) according to clinical protocols that employ two types of ionizing radiation: sparsely IR (i.e., X-rays) and densely IR (i.e., protons). Most cancer cells irradiated with therapeutic doses exhibit radio-induced cytotoxicity in terms of cell proliferation arrest and cell death by apoptosis. Nevertheless, despite the more tailored advances in RT protocols in the last few years, several tumors show a relatively high percentage of RT failure and tumor relapse due to their radioresistance. To counteract this extremely complex phenomenon and improve clinical protocols, several factors associated with radioresistance, of both a molecular and cellular nature, must be considered. Tumor genetics/epigenetics, tumor microenvironment, tumor metabolism, and the presence of non-malignant cells (i.e., fibroblast-associated cancer cells, macrophage-associated cancer cells, tumor-infiltrating lymphocytes, endothelial cells, cancer stem cells) are the main factors important in determining the tumor response to IR. Here, we attempt to provide an overview of how such factors can be taken advantage of in clinical strategies targeting radioresistant tumors.

Radiotherapy combined with immunotherapy: the dawn of cancer treatment

Radiotherapy (RT) is delivered for purposes of local control, but can also exert systemic effect on remote and non-irradiated tumor deposits, which is called abscopal effect. The view of RT as a simple local treatment has dramatically changed in recent years, and it is now widely accepted that RT can provoke a systemic immune response which gives a strong rationale for the combination of RT and immunotherapy (iRT). Nevertheless, several points remain to be addressed such as the interaction of RT and immune system, the identification of the best schedules for combination with immunotherapy (IO), the expansion of abscopal effect and the mechanism to amplify iRT. To answer these crucial questions, we roundly summarize underlying rationale showing the whole immune landscape in RT and clinical trials to attempt to identify the best schedules of iRT. In consideration of the rarity of abscopal effect, we propose that the occurrence of abscopal effect induced by radiation can be promoted to 100% in view of molecular and genetic level. Furthermore, the “radscopal effect” which refers to using low-dose radiation to reprogram the tumor microenvironment may amplify the occurrence of abscopal effect and overcome the resistance of iRT. Taken together, RT could be regarded as a trigger of systemic antitumor immune response, and with the help of IO can be used as a radical and systemic treatment and be added into current standard regimen of patients with metastatic cancer.

Immunotherapy in Genitourinary Malignancy: Evolution in Revolution or Revolution in Evolution

Immunotherapy, the 5th pillar of cancer care after surgery, radiotherapy, cytotoxic chemotherapy, and precision therapy (molecular targeted therapy), is revolutionizing the standard of care in certain patients with genitourinary malignancies. As modest clinical benefits of IL-2 for metastatic renal cell carcinoma and Bacillus Calmette-Guerin therapy for early-stage bladder cancers in the past years, immune checkpoint inhibitors therapies demonstrate meaningful survival benefit and durable clinical response in renal cell carcinoma, urothelial carcinoma, and some prostate cancer. Despite best efforts, the benefits are limited to a minority of unselected patients due to the complexities of biomarker development. Now come the next hurdles: figuring out which patients best respond to immune checkpoint inhibitors and which patients won't respond to immune checkpoint inhibitors? How best to approach immune checkpoint inhibitors therapies to extend/maximize the treatment response as long as possible? How to overcome therapeutic resistance by specific concurrent immunomodulators or targeted therapy or chemotherapy? The role of immune checkpoint inhibitors in combination or sequencing with chemotherapy or other targeted therapies or other immunomodulating therapeutics in the early disease, neoadjuvant, adjuvant, and metastatic setting is actively under exploration. Ideal strategy for cancer care is to provide not just more time, but more quality time: there remain unmet needs for novel therapies that exploit molecular or genetic pathways to extend survival without compromising health-related quality of life for patients with advanced genitourinary malignancies. Further research is needed to discover new therapeutic strategies, and validate efficacy and effectiveness in real-world settings.

Metastasis-Directed Radiation Therapy with Consolidative Intent for Oligometastatic Urothelial Carcinoma: A Systematic Review and Meta-Analysis

The management of patients with oligometastatic urothelial carcinoma (UC) represents an evolving field in uro-oncology, and the role of metastasis-directed therapies, including metastasectomy and metastasis-directed radiation therapy (MDRT), is gaining increasing attention. Herein, we summarize available evidence about the role of MDRT with consolidative intent in oligometastatic UC patients. A systematic review was performed in December 2021. Six studies involving 158 patients were identified. Most patients (n = 120, 90.2%) had a history of bladder cancer and the most frequent sites of metastases were lymph nodes (n = 61, 52.1%) followed by the lungs (n = 34, 29%). Overall, 144 metastases were treated with MDRT. Median follow-up ranged from 17.2 to 25 months. Local control rates ranged from 57% to 100%. Median Overall Survival (OS) ranged from 14.9 to 51.0 months and median progression-free survival ranged from 2.9 to 10.1 months. Rates of OS at one and two years ranged from 78.9% to 96% and from 26% to 63%, respectively. Treatment-related toxicity was recorded in few patients and in most cases a low-grade toxicity was evident. MDRT with consolidative intent represents a potential treatment option for selected patients with oligometastatic UC.

Use of immunotherapy in clinical management of genitourinary cancers - a review

Checkpoint inhibitors targeting PD-1/PD-L1 and CTLA-4 have revolutionized oncologic care delivery, including clinical management of genitourinary malignancies. Despite significant associated improvement in patient outcomes, molecular heterogeneity of tumors, variable tumor engagement with the immune response, and unique patient factors likely account for different clinical responses to immunotherapy agents. A search for predictive biomarkers of treatment response to checkpoint inhibitors is underway and several candidates, although imperfect, have been identified. Multiple checkpoint inhibitors have received approval as monotherapies or in combination with other agents in genitourinary cancers and clinical trial data continues to rapidly evolve. This review summarizes key published evidence involving use of checkpoint inhibitors in management of urothelial carcinoma, renal cell carcinoma, prostate adenocarcinoma, and penile squamous cell carcinoma. This review aims to help oncology practitioners develop an up-to-date, evidence-based approach to using these agents when managing patients with genitourinary cancers in clinical practice.