[Advanced bladder cancer : From chemo- to immunotherapy]

In November 2016, the results of a phase III clinical trial with the protein cell death (PD)-1 inhibitor pembrolizumab for second-line treatment of metastatic urothelial carcinoma were published and showed an overall survival benefit in comparison with conventional chemotherapy with vinflunine, docetaxel, or paclitaxel. In a similar trial the PD-L1 antibody atezolizumab showed no significant benefit in comparison to chemotherapy in the subgroup of PD-L1-positive patients and, thus, missed its primary endpoint. For other PD-1/PD-L1 directed substances, large phase I/II trials reported data concerning response rates and overall survival. This substance class will most likely become the new treatment standard in second-line treatment of metastatic urothelial cancer. Currently, PD-1/PD-L1 inhibitors are also being tested within randomized phase III trials for first-line treatment using different approaches either as a monotherapy or a combination with conventional chemotherapy or cytotoxic T‑lymphocyte-associated protein (CTLA)-4 inhibitors. Whereas data from single-arm phase II clinical trials have already been published, preliminary phase III data are expected in 2018.

[Immunotherapy with checkpoint inhibitors in local advanced and metastatic urothelial carcinoma]

The approval of immune checkpoint inhibitors has started a new era in the treatment of urothelial carcinoma, which, so far, has been a disease with limited treatment options. However, in the current German S3 guideline for bladder cancer the remarkable improvements provided by immune checkpoint inhibitors have not been reflected. As cancer immunotherapy is a novel approach, there are several questions related to the daily clinical routine: What clinical data was used as the basis for the approval of the individual substances? What does this mean for previous treatment algorithms? What issues must be considered in the management of adverse events? What side-effects may occur and how can they be recognised and treated? The present paper provides an overview of the new treatment options regarding their relevance as well as recommendations for their application in clinical practice.

Atezolizumab (atezo) vs. chemotherapy (chemo) in platinum-treated locally advanced or metastatic urothelial carcinoma (mUC): Immune biomarkers, tumor mutational burden (TMB), and clinical outcomes from the phase III IMvigor211 study

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Background: IMvigor211 is a global study of atezo vs chemo in platinum-treated mUC. The study did not meet its primary endpoint of overall survival (OS) in programmed death-ligand 1 (PD-L1)–selected patients (pts),1 but exploratory analyses showed improved OS for atezo in the intent-to-treat (ITT) population. Here we compare clinical outcomes in ITT and prespecified PD-L1 subgroups with those in subgroups defined by immune transcriptional gene expression (tGE) signatures and TMB. Methods: Pts with ≤ 2 prior lines of therapy for mUC who progressed during or following platinum treatment were randomized 1:1 to atezo or chemo (vinflunine, paclitaxel or docetaxel, per physician). The primary endpoint was OS, hierarchically compared between treatment arms in PD-L1–selected and ITT pts. Planned exploratory biomarker analyses included tGE (RNA-seq) and TMB (FoundationOne). Results: The ITT population included 931 pts (atezo arm, 467; chemo arm, 464), and biomarker-evaluable subgroups were representative of the ITT population. PD-L1 expression positively correlated with tGE (R = 0.61) but not TMB (R = 0.13). OS and hazard ratios (HRs) are listed in the Table. Conclusions: In this randomized Phase III study, we show that high PD-L1 and high tGE are associated with improved outcomes with both chemo and atezo. In contrast, higher TMB predicted OS in favor of atezo; however, clinical benefit with atezo was also seen in the ITT population. Clinical trial information: NCT02302807. [Table: see text]

Clinical experience with 100 consecutive patients treated with Lu-177-labeled PSMA-I&T radioligand therapy for metastatic castration-resistant prostate cancer

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Background: To report our clinical experience with 177Lutetium-labeled prostate-specific membrane antigen-ligand (177Lu-PSMA-I&T) for systemic radioligand therapy in 100 consecutive patients with metastatic castration-resistant prostate cancer (mCRPC). Methods: All patients were treated under a review board-approved compassionate use protocol. Eligibility criteria for 177Lu-PSMA-I&T therapy included previous treatment with abiraterone or enzalutamide, previous taxane-based chemotherapy or unsuitability for taxanes as well as positive 68Ga-PSMA tracer uptake of metastases in a prior PET-scan. Intravenous treatment with 177Lu-PSMA-I&T was given 6- to 8-weekly with an activity of 7.4GBq up to 6 cycles in patients without clinical or radiographic progression. We report prostate-specific antigen (PSA) decline, PSA progression-free survival (PSA-PFS), clinical progression-free survival (cPFS) and overall survival (OS) as well as toxicity. Results: Median age was 72 years (range 46-85) and median PSA level was 164 ng/ml (range 0-6178). Bone, lymph node and visceral metastases were present in 94%, 85% and 33% of patients, respectively. The median number of previous treatment regimens for mCRPC was 3 (range 1-6) and 84% of patients were pretreated with chemotherapy. At the time of evaluation, 286 cycles with 177Lu-PSMA-I&T were applied (median 2 cycles per patient, range 1-6), while treatment was still ongoing in 27% of patients. Overall, 4 and 6 cycles were applied in 33 and 15 patients, respectively. PSA decline ≥30%, ≥50% and ≥90% was achieved in 40%, 32% and 9% of patients, respectively. Median PSA-PFS was 3.4 months (95%CI 2.7-4.0), median cPFS was 4.1 months (95%CI 2.5-5.7) and median OS was 12.2 months (95%CI 8.8-15.7). Treatment-emergent hematologic grade 3/4 toxicities were anemia in 7%, thrombocytopenia in 5% and neutropenia in 4% of patients. Grade 3/4-non-hematologic toxicities were not observed. The main non-hematologic grade 1/2 toxicities were dry mouth in 18%, fatigue in 16% and loss of appetite in 9/% of patients. Conclusions: Radioligand therapy with 177Lu-PSMA I&T appears to be safe and active in late-stage mCRPC.

Vinflunine in the Treatment of Upper Tract Urothelial Carcinoma - Subgroup Analysis of an Observational Study

BACKGROUND/AIM

Despite an expected prognostic disadvantage for upper tract versus lower tract metastatic urothelial carcinomas (UTUC/LTUC), only few studies have been conducted to elucidate potential differences in chemotherapy treatment.

PATIENTS AND METHODS

A post-hoc subgroup analysis of a non-interventional study investigating vinflunine after failure of a platinum-based chemotherapy in metastatic/locally advanced UC patients was performed.

RESULTS

A total of 18 and 59 out of 77 patients had UTUC and LTUC, respectively. The effectiveness of vinflunine treatment was comparable with an overall response rate of 22.2% and 23.7% respectively and a median progression-free survival of 2.76 months in both groups. Median overall survival was 5.0 months in UTUC compared to 8.2 months in the LTUC group (p=0.478). The safety profile was in accordance with previous vinflunine experiences, with a comparable frequency of adverse events in both groups.

CONCLUSION

Vinflunine can be applied in the 2nd line for UC regardless of the primary tumor localization.

[PSMA-targeted radioligand therapy in prostate cancer]

Radioligand therapy (RLT) directed against prostate-specific membrane antigen (PSMA) enables tumor-specific treatment directed against PSMA-overexpressing prostate cancer cells. Several PSMA ligands such as PSMA-617 or PSMA-I&T have been developed that can be labeled with β‑radiating lutetium-177. These are currently applied in compassionate use programs to treat metastatic castration-resistant prostate cancer (mCRPC). PSMA-directed RLT is currently being offered in several nuclear medicine departments throughout Germany. Several retrospective case series demonstrate its activity with a prostate-specific antigen (PSA) decrease >50% in 30-60% of mCRPC patients. The toxicity seems to be low. Hematologic grade 4 toxicity has not been observed and grade 3 toxicities rarely occur. The main nonhematologic adverse events are intermittent dry mouth because of unspecific PSMA expression in the salivary glands as well as fatigue and nausea. Currently there are no prospective studies available for evaluation of PSMA-targeted RLT and a survival benefit over approved standard therapies such as abiraterone, enzalutamide, radium-223-dichloride, docetaxel or cabazitaxel has not been shown. PSMA-targeted RLT should therefore currently only be offered after critical evaluation in patients who exhausted the approved standard therapies.

AR-V7 in Peripheral Whole Blood of Patients with Castration-resistant Prostate Cancer: Association with Treatment-specific Outcome Under Abiraterone and Enzalutamide

BACKGROUND

It has been demonstrated that androgen receptor splice variant 7 (AR-V7) expression in circulating tumor cells (CTCs) predicts poor treatment response in metastatic castration-resistant prostate cancer (mCRPC) patients treated with abiraterone or enzalutamide.

OBJECTIVE

To develop a practical and robust liquid profiling approach for direct quantification of AR-V7 in peripheral whole blood without the need for CTC capture and to determine its potential for predicting treatment response in mCRPC patients.

DESIGN, SETTING, AND PARTICIPANTS

Whole blood samples from a prospective biorepository of 85 mCRPC patients before treatment initiation with abiraterone (n=56) or enzalutamide (n=29) were analyzed via droplet digital polymerase chain reaction.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The association of AR-V7 status with prostate-specific antigen (PSA) response defined by PSA decline ≥50% and with PSA-progression-free survival (PSA-PFS), clinical PFS, and overall survival (OS) was assessed.

RESULTS AND LIMITATIONS

High AR-V7 expression levels in whole blood were detectable in 18% (15/85) of patients. No patient with high AR-V7 expression achieved a PSA response, and AR-V7 status was an independent predictor of PSA response in multivariable logistic regression analysis (p=0.03). High AR-V7 expression was associated with shorter PSA-PFS (median 2.4 vs 3.7 mo; p<0.001), shorter clinical PFS (median 2.7 vs 5.5 mo; p<0.001), and shorter OS (median 4.0 vs. 13.9 mo; p<0.001). On multivariable Cox regression analysis, high AR-V7 expression remained an independent predictor of shorter PSA-PFS (hazard ratio [HR] 7.0, 95% confidence interval [CI] 2.3-20.7; p<0.001), shorter clinical PFS (HR 2.3, 95% CI 1.1-4.9; p=0.02), and shorter OS (HR 3.0, 95% CI 1.4-6.3; p=0.005).

CONCLUSIONS

Testing of AR-V7 mRNA levels in whole blood is a simple and promising approach to predict poor treatment outcome in mCRPC patients receiving abiraterone or enzalutamide.

PATIENT SUMMARY

We established a method for determining AR-V7 status in whole blood. This test predicted treatment resistance in patients with metastatic castration-resistant prostate cancer undergoing treatment with abiraterone or enzalutamide. Prospective validation is needed before application to clinical practice.

[The role of immunooncology in the treatment of urothelial cancer]

Data published in November 2016 showed a significant survival benefit for the PD-1 antibody Pembrolizumab in the second-line treatment of metastatic urothelial cancer in comparison to standard chemotherapy. Other PD-1/PD-L1 antibodies are being tested in advanced clinical trials. This class of substances will become standard of care from the time of their approval which is expected for 2017 and will replace vinflunine, which is currently recommended in the German guideline. PD-1/PD-L1 directed substances are also being tested as a first line treatment of metastatic urothelial carcinoma. Monotherapy is evaluated as well as combination treatments with CTLA-4 inhibitors of conventional chemotherapy. First data are expected at the end of 2017.A new strategy is the application of PD-1/PD-L1 directed substances in the perioperative treatment of patients with a muscle-invasive urothelial carcinoma after complete surgical resection (cystectomy or nephroureterectomy). Two international phase III trials evaluate an adjuvant immunotherapy with nivolumab and atezolizumab. Recruitment will be completed in 2018.

Exploring New Multimodal Quantitative Imaging Indices for the Assessment of Osseous Tumor Burden in Prostate Cancer Using 68Ga-PSMA PET/CT

PET combined with CT and prostate-specific membrane antigen (PSMA) ligands has gained significant interest for staging prostate cancer (PC). In this study, we propose 2 multimodal quantitative indices as imaging biomarkers for the assessment of osseous tumor burden using ⁶⁸Ga-PSMA PET/CT and present preliminary clinical data. Methods: We defined 2 bone PET indices (BPIs) that incorporate anatomic information from CT and functional information from ⁶⁸Ga-PSMA PET: BPI_VOL is the percentage of bone volume affected by tumor and BPI_SUV additionally considers the level of PSMA expression. We describe a semiautomatic computation method based on segmentation of bones in CT and of lesions in PET. Data from 45 patients with castration-resistant PC and bone metastases during ²²³Ra-dichloride were retrospectively analyzed. We evaluated the computational stability and reproducibility of the proposed indices and explored their relation to the prostate-specific antigen blood value, the bone scan index (BSI), and disease classification using PERCIST. Results: On the technical side, BPI_VOL and BPI_SUV showed an interobserver maximum difference of 3.5%, and their computation took only a few minutes. On the clinical side, BPI_VOL and BPI_SUV showed significant correlations with BSI (r = 0.76 and 0.74, respectively, P < 0.001) and prostate-specific antigen values (r = 0.57 and 0.54, respectively, P < 0.01). When the proposed indices were compared against expert rating using PERCIST, BPI_VOL and BPI_SUV showed better agreement than BSI, indicating their potential for objective response evaluation. Conclusion: We propose the evaluation of BPI_VOL and BPI_SUV as imaging biomarkers for ⁶⁸Ga-PSMA PET/CT in a prospective study exploring their potential for outcome prediction in patients with bone metastases from PC.

Health-related quality of life as a marker of treatment benefit with nivolumab in platinum-refractory patients with metastatic or unresectable urothelial carcinoma from CheckMate 275

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Background: CheckMate 275 (NCT02387996), a phase II, single-arm study of nivolumab (3 mg/kg every 2 weeks) treatment in platinum-refractory patients (pts) with metastatic urothelial carcinoma, showed an objective response rate of 19.6% (95% CI, 15.0%–24.9%) with manageable toxicity. The objective of this analysis was to examine the impact of nivolumab on health-related quality of life (HRQoL) in the study. Methods: HRQoL was measured using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) and three-level EQ-5D (EQ-5D-3L) and visual analog scale (VAS). Questionnaires were completed at baseline and every 8 weeks thereafter for the first 48 weeks. The analysis cohort included pts with scores recorded at baseline and ≥1 postbaseline assessments while on treatment. Data were analyzed using mixed models, adjusting for baseline score. Results: Of the 270 patients treated with nivolumab, 168 (62%) had an assessment at baseline and ≥1 postbaseline assessment and were included in HRQoL analyses. Completion rates at baseline were 97% for both questionnaires. Statistically significant ( P< 0.05) improvements in mean scores for the EORTC QLQ-C30 subscales measuring role, emotional, and social functioning; global health status/quality of life; nausea/vomiting; pain; dyspnea; insomnia; appetite loss; constipation; and diarrhea were observed at ≥1 time points. With the exception of cognitive functioning, no significant worsening in subscale scores was observed in the EORTC QLQ-C30. Statistically significant and clinically meaningful improvement (based on a minimally important difference of 7) in EQ-5D VAS was noted between weeks 17 and 41. EQ-5D-3L utility index scores based on the UK tariff remained stable during treatment. Conclusions: Results of CheckMate 275 indicate that pts with metastatic or unresectable urothelial carcinoma whose disease progressed or recurred after treatment with a platinum agent exhibited stable, or in some cases statistically significantly improved, HRQoL while being treated with nivolumab, as measured by EORTC QLQ-C30 and EQ-5D-3L. Clinical trial information: NCT02387996.

Wntless promotes bladder cancer growth and acts synergistically as a molecular target in combination with cisplatin

PURPOSE

To analyze the contribution of Wnt signaling pathway to bladder cancer growth in order to identify suitable target molecules for therapy.

MATERIAL AND METHODS

Expression of Wnt 2/4/7, LRP5/6, TCF1/2/4, LEF-1, and β-actin was detected by reverse transcription polymerase chain reaction in a panel of 9 and for Wntless (WLS) in 17 bladder cancer cell lines. Protein expression of WLS was detected in 6 cell lines. Wnt/β-catenin activity was analyzed using the TOPflash/FOPflash luciferase reporter assay. Expression level of β-catenin, WIF1, Dickkopf proteins (DKK), HSulf-2, sFRP4, and WLS was modulated by transfecting or infecting cells transiently or stably with respective shRNAs, siRNAs, or cDNAs. For protein detection, whole cell lysates were applied to sodium dodecyl sulfate polyacrylamide gel electrophoresis followed by immunoblots. Effects on cell growth were determined by cell viability assays and BrdU/APC incorporation/staining. For 3-dimensional tumor growth, the chicken chorioallantoic membrane model was used. Tumor growth was characterized by weight.

RESULTS

Expression of molecular components and activation of the Wnt signaling pathway could be detected in all cell lines. Expression level of β-catenin, WIF1, DKK, WLS, and HSulf-2 influenced Wnt activity. Expression of WLS was confirmed in 17 cell lines by reverse transcription polymerase chain reaction and in 6 cell lines by immunoblotting. WLS positively regulates Wnt signaling, cell proliferation, and tumor growth in vitro and in vivo. These effects could be reversed by the expression of the Wnt antagonist WIF1 and DKK. Synergistic activity of cisplatin and WLS inactivation by genetic silencing could be observed on cell viability.

CONCLUSION

The Wnt signaling pathway is ubiquitously activated in bladder cancer and regulates tumor growth. WLS might be a target protein for novel therapies in combination with established chemotherapy regimens.

Atezolizumab (atezo) in platinum-treated locally advanced or metastatic urothelial carcinoma (mUC): Outcomes by prior therapy

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Background: Atezo is approved in the US for mUC and non-small cell lung cancer after prior treatment with chemotherapy. > 40% of mUC pts in the Phase 2 IMvigor210 study received ≥ 2prior metastatic regimens (Rosenberg, Lancet 2016). This analysis was performed to assess the impact of prior therapy on atezo outcomes in mUC. Methods: mUC pts in the platinum-pretreated IMvigor210 cohort (NCT02108652) received atezo 1200 mg IV q3w until loss of clinical benefit. Study endpoints analyzed by the number of prior treatment regimens included RECIST v1.1 ORR (central review), complete response (CR) rate, median durations of response (mDOR) and survival (mOS) and adverse event rate. Results: Evaluable pts (N = 310) had a median age of 66 years, and 78% had visceral mets (31% liver). 82% of pts had prior systemic treatment for mUC; number of prior regimens ranged from 1 to ≥ 4 (Table). 73% of pts received prior cisplatin, and 26% had carboplatin (no cisplatin). Objective responses, including CRs, occurred regardless of the number of prior therapies and were ongoing in 65% of responders at the July 4, 2016 data cut off (median follow-up, 21 mo [range, 0.2+-24.5]). mDOR was not reached in any subgroup based on number of treatments, except in pts who received only perioperative chemotherapy (mDOR, 16 mo [95% CI: 6.2, NE]). Similarly, mOS was generally consistent despite number of prior regimens (Table). Atezo remained generally well tolerated with similar overall safety and tolerability by line of therapy. Conclusions: Clinically meaningful benefit was observed in pts treated with atezo notwithstanding number of prior systemic mUC regimens. Minimally and heavily pre-treated pts had durable responses, encouraging OS and no major differences in safety signals. Clinical trial information: NCT02108652. [Table: see text]

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.

The Role of PD-L1 Expression and Intratumoral Lymphocytes in Response to Perioperative Chemotherapy for Urothelial Carcinoma

Introduction: Immunological pathways are relevant for the effectiveness of conventional cytotoxic chemotherapy. Recently, checkpoint inhibition of the PD-1/PD-L1 axis has been shown to be therapeutically relevant in urothelial carcinoma. Objective: To monitor PD-L1 expression on tumor cells and intratumoral infiltration with CD8 positive lymphocytes during perioperative chemotherapy for urothelial cancer and to evaluate their use as potential predictive markers for chemotherapy. Patients and Methods: Sixty-four patients with muscle-invasive urothelial cancer were included in the analysis. Twenty-two patients received preoperative chemotherapy and 42 were treated in an adjuvant setting for locally advanced disease or lymph node metastases. PD-L1 status and the density of infiltration with CD8-positive cells were assessed by immunohistochemistry and analysed for their association with survival (adjuvant group) and response to chemotherapy (preoperative group). For PD-L1 positivity we used a cutoff of 10% positive tumor cells. Results: In the adjuvant group, 11 of 42 patients (26.2%) had PD-L1 positive tumor cells. Twenty-six of 42 (61.9%) patients were highly infiltrated with CD8 + lymphocytes. There was no significant evidence of an association with overall survival for PD-L1 status nor for CD8 infiltration density (p = 0.63 and 0.71). In the preoperative group, eight of the 22 (36.4%) patients were PD-L1 positive and 13 (59%) were highly infiltrated with CD8 + lymphocytes before chemotherapy. There was no evidence of associations with response or survival. Eight patients showed a pathological response to preoperative treatment. These had a significantly longer overall survival than non-responders (p = 0.01). In the preoperative group the pre-treatment expression of the immunologic markers could be compared to the post-treatment status. Only one patient showed a changed PD-L1 status and three patients a changed CD8 status. Conclusions: The tumoral expression of PD-L1 in urothelial carcinoma does not seem to be largely influenced by chemotherapy. Our data do not provide evidence that tumoral expression of PD-L1 and CD8 are useful as prognostic or predictive markers. Small sample size is the major limitation of our study.