Second-line systemic therapy for metastatic urothelial carcinoma of the bladder

Myeloid-derived suppressor cells are essential partners for immune checkpoint inhibitors in the treatment of cisplatin-resistant bladder cancer

Myeloid-derived suppressor cells (MDSCs) are one of the key players that contribute to immune evasion. The purpose of the present study was to investigate whether MDSCs could be a novel target for the treatment of cisplatin-resistant bladder cancer. We established cisplatin-resistant bladder cancer cell lines (MB49R, MBT-2R, and T24R) and evaluated chemokine expression and MDSC expansion. We also assessed the antitumor effect by depleting MDSCs with or without a α-PD-L1 antibody using MB49R xenograft models. The chemokine expression of CXCL1, CXCL2, and CCL2 increased in cisplatin-resistant cells compared to those in their parent strains. Monocytic MDSCs (Mo-MDSCs) were observed more frequently compared to polymorphonuclear MDSCs (PMN-MDSCs) in MB49R tumors. The immunosuppressive genes arginase 1 and iNOS were comparably expressed in each MDSC subtype. In vivo, combination therapy targeting both PMN- and Mo-MDSCs using α-Gr1 and α-Ly6C antibodies significantly reduced tumor volume with increased infiltration of CD8 T cells in the tumor. Finally, co-targeting pan-MDSCs and PD-L1 remarkably reduced the tumor growth. These findings suggest that targeting MDSCs might enhance the therapeutic effect of immune checkpoint inhibitors in cisplatin-resistant bladder cancers.

Development of immunotherapy in bladder cancer: present and future on targeting PD(L)1 and CTLA-4 pathways

PURPOSE

Over the past 3 decades, no major treatment breakthrough has been reported for advanced bladder cancer. Recent Food and Drug Administration (FDA) approval of five immune checkpoint inhibitors in the management of advanced bladder cancer represent new therapeutic opportunities. This review examines the available data of the clinical trials leading to the approval of ICIs in the management of metastatic bladder cancer and the ongoing trials in advanced and localized settings.

METHODS

A literature search was performed on PubMed and ClinicalTrials.gov combining the MeSH terms: 'urothelial carcinoma' OR 'bladder cancer', and 'immunotherapy' OR 'CTLA-4' OR 'PD-1' OR 'PD-L1' OR 'atezolizumab' OR 'nivolumab' OR 'ipilimumab' OR 'pembrolizumab' OR 'avelumab' OR 'durvalumab' OR 'tremelimumab'. Prospectives studies evaluating anti-PD(L)1 and anti-CTLA-4 monoclonal antibodies were included.

RESULTS

Evidence-data related to early phase and phase III trials evaluating the 5 ICIs in the advanced urothelial carcinoma are detailed in this review. Anti-tumour activity of the 5 ICIs supporting the FDA approval in the second-line setting are reported. The activity of PD(L)1 inhibitors in the first-line setting in cisplatin-ineligible patients are also presented. Ongoing trials in earlier disease-states including non-muscle-invasive and muscle-invasive bladder cancer are discussed.

CONCLUSIONS

Blocking the PD-1 negative immune receptor or its ligand, PD-L1, results in unprecedented rates of anti-tumour activity in patients with metastatic urothelial cancer. However, a large majority of patients do not respond to anti-PD(L)1 drugs monotherapy. Investigations exploring the potential value of predictive biomarkers, optimal combination and sequences are ongoing to improve such treatment strategies.

Comparison of efficacy and toxicity of second-line combination chemotherapy regimens in patients with advanced urothelial carcinoma

BACKGROUND

The aim of this study was to evaluate the efficacy and toxicities of second-line chemotherapy regimens with docetaxel and gemcitabine (GD), or paclitaxel and gemcitabine (GP) for advanced or metastatic urothelial carcinoma (UC) that did not respond to first-line platinum-based chemotherapy.

METHODS

From 2002 to 2017, 78 patients with metastatic UCs that progressed after platinum-based chemotherapy were treated with either GD (n = 41) or GP (n = 37). We compared these two different regimens by analyzing their efficacy and toxicities in a retrospective manner.

RESULTS

Of the 78 patients enrolled in this study, it was possible to determine treatment efficacy in 70; the proportion of patients with objective response and disease control were 8.6 (9/70) and 54.3% (38/70), respectively. The median progression-free survival and overall survival in the total population (GP and GD) were 3.5 (95% CI 0.6-53.3) and 9.6 months (95% CI 1.2-53.3), respectively. There was no significant difference between the two regimens (GD or GP) regarding survival outcomes. Treatment-related adverse events were mostly manageable, but one patient died as a result of febrile neutropenia. The presence of liver metastasis and anemia (Hb < 10.0 g/dl) was prognostic factors for worse survival.

CONCLUSIONS

Combination chemotherapy with either GP or GD was a favorable and well-tolerated second-line treatment regimen for patients with advanced or metastatic UC following the failure of a platinum-based regimen. Further study using a large prospective cohort is needed to identify patients who will benefit from second-line combination therapy.

Pharmacogenomic considerations in the treatment of muscle-invasive bladder cancer

Recent advances in next-generation sequencing techniques have greatly improved our understanding of the genomic alterations in bladder cancer. Cisplatin-based chemotherapy provides a viable treatment option in the neoadjuvant, adjuvant and metastatic setting in a selected group of patients, but chemoresistance is a major problem. The underlying mechanisms of treatment resistance are poorly understood and elucidating these pathways will subsequently lead to improved patient selection, less unnecessary drug-related toxicity, improved patient outcome and decreased healthcare costs. This review provides an overview of mechanisms of chemoresistance and describes the current knowledge on how the genomic landscape influences therapy outcome in muscle-invasive bladder cancer patients.

Spotlight on atezolizumab and its potential in the treatment of advanced urothelial bladder cancer

Metastatic urothelial carcinoma of the bladder is an aggressive malignancy with poor prognosis, reflecting a lack of effective systemic therapies. The current standard of care includes multiagent platinum-based chemotherapy; however a majority of patients do not respond to treatment and most eventually succumb to disease. Recently, renewed interest in immunotherapy in the form of immune-checkpoint inhibition has gained widespread attention for a number of malignancies. Atezolizumab, an anti-PDL1 antibody, has been shown to be effective in a subset of patients previously treated with or unfit for platinum-based chemotherapy, and has shown durable responses with a good tolerability profile. We review the mechanism of action and clinical evidence of atezolizumab for metastatic urothelial bladder cancer, and discuss this drug within the context of ongoing developments in this dynamic field of immunooncology.

Nivolumab in metastatic urothelial carcinoma after platinum therapy (CheckMate 275): a multicentre, single-arm, phase 2 trial

BACKGROUND

Patients with metastatic urothelial carcinoma have a dismal prognosis and few treatment options after first-line chemotherapy. Responses to second-line treatment are uncommon. We assessed nivolumab, a fully human IgG4 PD-1 immune checkpoint inhibitor antibody, for safety and activity in patients with metastatic or surgically unresectable urothelial carcinoma whose disease progressed or recurred despite previous treatment with at least one platinum-based chemotherapy regimen.

METHODS

In this multicentre, phase 2, single-arm study, patients aged 18 years or older with metastatic or surgically unresectable locally advanced urothelial carcinoma, measurable disease (according to Response Evaluation Criteria In Solid Tumors v1.1), Eastern Cooperative Oncology Group performance statuses of 0 or 1, and available tumour samples for biomarker analysis received nivolumab 3 mg/kg intravenously every 2 weeks until disease progression and clinical deterioration, unacceptable toxicity, or other protocol-defined reasons. The primary endpoint was overall objective response confirmed by blinded independent review committee in all treated patients and by tumour PD-L1 expression (≥5% and ≥1%). This trial is registered with ClinicalTrials.gov, number NCT02387996, and is completed. Follow-up is still ongoing.

FINDINGS

Between March 9, 2015, and Oct 16, 2015, 270 patients from 63 sites in 11 countries received nivolumab, and 265 were evaluated for activity. Median follow-up for overall survival was 7·00 months (IQR 2·96-8·77). Confirmed objective response was achieved in 52 (19·6%, 95% CI 15·0-24·9) of 265 patients. Confirmed objective response was achieved in 23 (28·4%, 95% CI 18·9-39·5) of the 81 patients with PD-L1 expression of 5% or greater, 29 (23·8%, 95% CI 16·5-32·3) of the 122 patients with PD-L1 expression of 1% or greater, and 23 (16·1%, 95% CI 10·5-23·1) of the 143 patients with PD-L1 expression of less than 1%. Grade 3-4 treatment-related adverse events occurred in 48 (18%) of 270 patients-most commonly grade 3 fatigue and diarrhoea, which each occurred in five patients. Three deaths were attributed to treatment (pneumonitis, acute respiratory failure, and cardiovascular failure).

INTERPRETATION

Nivolumab monotherapy provided meaningful clinical benefit, irrespective of PD-L1 expression, and was associated with an acceptable safety profile in previously treated patients with metastatic or surgically unresectable urothelial carcinoma.

FUNDING

Bristol-Myers Squibb.

Second-Line Chemotherapy for Metastatic Urothelial Carcinoma: Importance of Lymph Node-Only Metastasis as a Prognostic Factor and Construction of a Prognostic Model

BACKGROUND

A prognostic model for patients with metastatic urothelial carcinoma (UC) progressing after platinum-based therapy was constructed from data from the phase III vinflunine trial. However, prognostic information for patients treated with other regimens is limited.

MATERIALS AND METHODS

We pooled individual patient data from 7 second-line studies and analyzed the influence of factors of interest on overall survival (OS) through univariate and multivariate analysis. A prognostic model was constructed, and data from an independent series were used for validation.

RESULTS

The data from 193 patients were pooled. The second-line chemotherapy regimen was single-agent taxane in 54 patients (28%), a platinum-based combination in 47 (24%), and a non-platinum combination in 92 (48%). On multivariate analysis, Eastern Cooperative Oncology Group performance status ≥ 1, hemoglobin < 10 g/dL, and metastatic patterns other than lymph node-only metastasis emerged as independent adverse prognostic factors. Patients with all 3 factors (poor risk), 1 to 2 factors (intermediate risk), and no factors (good risk) had a median OS of 3.1, 8.7, and 16.5 months, respectively (P < .0001). The corresponding median OS for the validation series (n = 44) was 3.3, 8.1, and 13.3 months (P = .023). Furthermore, platinum-based regimens were independently associated with an OS benefit compared with other regimens (hazard ratio, 0.31; 95% confidence interval, 0.18-0.53; P < .0001).

CONCLUSION

We have proposed and validated a prognostic model for patients with metastatic UC who were eligible for second-line therapy. The proposed model could prove helpful for risk stratification. Furthermore, our data suggest that testing second-line platinum-based regimens in randomized trials is warranted.

The role of genomics in the management of advanced bladder cancer

OPINION STATEMENT

Advanced bladder cancer (ABC) is an aggressive malignancy with a poor prognosis. For the last 30 years, the standard of care for this disease has consisted of combination chemotherapy with a platinum-containing regimen as first-line therapy. Cisplatin is the most active cytotoxic agent against bladder cancer, but because of competing comorbidities, many patients are ineligible for this agent and instead receive carboplatin. The two-drug regimen of cisplatin and gemcitabine was found to be better tolerated and have comparable efficacy as the four-drug regimen of methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC) in a randomized study of patients with advanced disease. Therefore, cisplatin (or carboplatin) and gemcitabine is the most commonly used first-line regimen in this setting. No agents have been approved by the Food and Drug Administration (FDA) for second-line therapy in ABC. If patients are eligible for additional systemic treatment at the time of progression, options include single-agent therapy such as a taxane or pemetrexed, though given the lack of standard approaches participation in a clinical trial should be strongly encouraged. Recent molecular characterization of ABC reveals significant genetic heterogeneity and actionable genomic alterations in the majority of tumors. Emerging therapies may effectively target known molecular drivers of ABC, including the FGFR2, EGFR/HER2, VEGF, MET, and PI3/AKT/mTOR pathways. Reports of dramatic and prolonged responses to targeted therapy provide additional support for the use of genome sequencing in the rationale selection of treatment for subsets of patients. The current focus of clinical trial development is to design molecularly driven studies that "match" tumors with driver mutations and appropriate targeted therapies rather than a "one-size-fits-all" approach based on clinical and pathologic parameters of disease. The hope of patients and clinicians alike is that this therapeutic approach combined with novel agents may usher in a new era of effective treatments for patients with ABC.

Elevating the Horizon: Emerging Molecular and Genomic Targets in the Treatment of Advanced Urothelial Carcinoma

Despite recent advances in the identification of genomic alterations that lead to urothelial oncogenesis in vitro, patients with advanced urothelial carcinomas continue to have poor clinical outcomes. In the present review, we focus on targeted therapies that have yielded the most promising results alone or combined with traditional chemotherapy, including the antiangiogenesis agent bevacizumab, the human epidermal growth factor receptor 2 antibody trastuzumab, and the tyrosine kinase inhibitor cabozantinib. We also describe ongoing and developing clinical trials that use innovative approaches, including dose-dense scheduling of singular chemotherapy combinations, prospective screening of tumor tissues for mutational targets and biomarkers to predict chemosensitivity before the determination of the therapeutic regimen, and novel agents that target proteins in the immune checkpoint regulation pathway (programmed cell death protein 1 [PD-1] and anti-PD-ligand 1) that have shown significant potential in preclinical models and early clinical trials. New agents and targeted therapies, alone or combined with traditional chemotherapy, will only be validated through accrual to developing clinical trials that aim to translate these therapies into individualized treatments and improved survival rates in urothelial carcinoma.

Lentinan reduces tumor progression by enhancing gemcitabine chemotherapy in urothelial bladder cancer

It has been shown that chemotherapy has limited antitumor activity against advanced urothelial bladder cancer (UBC). Consequently, there is an urgent need to develop effective therapeutic methods for patients with advanced UBC. In the present study, the inhibitory effects of lentinan alone, gemcitabine alone, or lentinan combined with gemcitabine on the proliferation of the UBC cell line, T24, were investigated. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, annexin V fluorescein isothiocyanate/propidium iodide staining, and flow cytometry were used to determine the proliferation and apoptosis of T24 cells in each treatment group. Survival-related protein expression was analyzed by western blotting. Increased concentrations of lentinan, or lentinan combined with gemcitabine, positively correlated with decreased T24 cell proliferation. Lentinan combined with gemcitabine chemotherapy significantly inhibited UBC cell proliferation. Gemcitabine has the ability to induce T24 cell apoptosis, and this effect is enhanced when it is combined with lentinan.

Targeted therapies in urothelial carcinoma

PURPOSE OF REVIEW

Greater understanding of the biology and genetics of urothelial carcinoma is helping to identify and define the role of molecules and pathways appropriate for novel-targeted therapies. Here, we review the targeted therapies that have been reported or are in ongoing urothelial carcinoma clinical trials, and highlight molecular targets characterized in preclinical and clinical studies.

RECENT FINDINGS

Trials in nonmuscle-invasive bladder cancer are evaluating the role of immunotherapy and agents targeting vascular endothelial growth factor (VEGF) or fibroblast growth factor receptor-3. In muscle-invasive bladder cancer, neoadjuvant studies have focused on combining VEGF agents with chemotherapy; adjuvant studies are testing vaccines and agents targeting the human epidermal growth factor receptor 2, p53, and Hsp27. In the first-line treatment of metastatic urothelial carcinoma, tubulin, cytotoxic T-lymphocyte antigen 4, Hsp27, and p53 are novel targets in clinical trials. The majority of targeted agents studied in urothelial carcinoma are in the second-line setting; new targets include CD105, polo-like kinase-1, phosphatidylinositide 3-kinases (PI3K), transforming growth factor β receptor/activin receptor-like kinase β, estrogen receptor, and the hepatocyte growth factor receptor (HGFR or MET).

SUMMARY

Development of targeted therapies for urothelial carcinoma is still in early stages, consequently there have been no major therapeutic advances to date. However, greater understanding of urothelial carcinoma and solid tumor biology has resulted in a proliferation of clinical trials that could lead to significant advances in treatment strategies.

Microtubule-targeting agents in oncology and therapeutic potential in hepatocellular carcinoma

In mammalian cells, microtubules are present both in interphase and dividing cells. In the latter, microtubules forming the mitotic spindle are highly dynamic and exquisitely sensitive to therapeutic inhibitors. Developed to alter microtubule function, microtubule-binding agents have been proven to be highly active as an anticancer treatment. Significant development of microtubule-binding agents has taken place in recent years, with newer anti-tubulin agents now showing novel properties of enhanced tumor specificity, reduced neurotoxicity, and insensitivity to chemoresistance mechanisms. Hepatocellular carcinoma remains one of the most difficult cancers to treat, with chemotherapies being relatively ineffective. There is now evidence to suggest that microtubule-binding agents may be effective in the treatment of hepatocellular carcinoma, especially when used in combination with mammalian target of rapamycin inhibitors. Preclinical models have suggested that the latter may be able to overcome resistance to microtubule binding agents. In this review article, recent developments of novel microtubule binding agents and their relevance to the treatment of hepatocellular carcinoma will be discussed.