Despite extensive investigation over the past three decades, cancer immunotherapy has produced limited success, with few agents achieving approval by the Food and Drug Administration and even the most effective helping only a minority of patients, primarily with melanoma or renal cancer. In recent years, immune checkpoints that maintain physiologic self-tolerance have been implicated in the down-regulation of anti-tumor immunity. Efforts to restore latent anti-tumor immunity have focused on antibody-based interventions targeting CTL antigen 4 (CTLA-4) and programmed cell death protein 1 (PD-1) on T lymphocytes and its principal ligand (PD-L1) on tumor cells. Ipilimumab, an antibody targeting CTLA-4, appears to restore tumor immunity at the priming phase, whereas anti-PD-1/PD-L1 antibodies restore immune function in the tumor microenvironment. Although ipilimumab can produce durable long-term responses in patients with advanced melanoma, it is associated with significant immune-related toxicities. By contrast, antibodies targeting either PD-1 or PD-L1 have produced significant anti-tumor activity with considerably less toxicity. Activity was seen in patients with melanoma and renal cancer, as well as those with non-small-cell lung, bladder and head and neck cancers, tumors not previously felt to be sensitive to immunotherapy. The tolerability of PD-1-pathway blockers and their unique mechanism of action have made them ideal backbones for combination regimen development. Combination approaches involving cytotoxic chemotherapy, anti-angiogenic agents, alternative immune-checkpoint inhibitors, immunostimulatory cytokines and cancer vaccines are currently under clinical investigation. Current efforts focus on registration trials of single agents and combinations in various diseases and disease settings and identifying predictive biomarkers of response.

Background: Recent studies have shown that minichromosome maintenance (MCM) proteins (Mcm2-7) may be useful proliferation markers in dysplasia and cancer in various tissues. Aims: To investigate the use of Mcm7 as a proliferation marker in 79 lymph node negative prostate cancers and compare it with Ki-67, a commonly used cell proliferation marker. Methods: The percentage of proliferating cells (proliferation index; PI) was calculated for basal and luminal epithelial cells in benign prostate tissue, prostatic intraepithelial neoplasia (PIN), and epithelial cells in adenocarcinoma. The PI for each biomarker was correlated with the preoperative prostate specific antigen concentration, the Gleason score, surgical resection margin status, and the AJCC pT stage for each patient. Results: The mean PIs for Ki-67 and Mcm7 were: benign luminal epithelium 0.7 and 1.2 and benign basal epithelium 0.8 and 8.2; PIN non-basal epithelium 4.9 and 10.6 and PIN basal epithelium 0.7 and 3.1; adenocarcinoma 9.8 and 22.7, respectively. Mcm7 had a significantly higher mean PI (p,0.0001) than Ki-67 for all cell categories except benign luminal epithelial cells. Mcm7 was a better discriminatory marker of proliferation between benign epithelium, PIN, and invasive adenocarcinoma (p,0.0001) than Ki-67. The drop in Mcm7 mean basal cell PI from benign epithelium to PIN epithelium was significantly larger than for Ki-67 (p,0.0001). Mcm7 had a significantly higher PI than Ki-67 at each risk level. Conclusion: Mcm7 may be a useful proliferation marker in prostatic neoplasia and warrants further evaluation as a complementary tool in the diagnosis of PIN and prostate carcinoma.

PURPOSE Platinum-based chemotherapy for first-line treatment of metastatic urothelial cancer is typically administered for a fixed duration followed by observation until progression. “Switch maintenance” therapy with PD-1 blockade at the time of chemotherapy cessation may be attractive for mechanistic and pragmatic reasons. PATIENTS AND METHODS Patients with metastatic urothelial cancer achieving at least stable disease on first-line platinum-based chemotherapy were enrolled. Patients were randomly assigned double-blind 1:1 to switch maintenance pembrolizumab 200 mg intravenously once every 3 weeks versus placebo for up to 24 months. Patients with disease progression on placebo could cross over to pembrolizumab. The primary objective was to determine the progression-free survival. Secondary objectives included determining overall survival as well as treatment outcomes according to PD-L1 combined positive score (CPS). RESULTS Between December 2015 and November 2018, 108 patients were randomly assigned to pembrolizumab (n = 55) or placebo (n = 53). The objective response rate was 23% with pembrolizumab and 10% with placebo. Treatment-emergent grade 3-4 adverse events occurred in 59% receiving pembrolizumab and 38% of patients receiving placebo. Progression-free survival was significantly longer with maintenance pembrolizumab versus placebo (5.4 months [95% CI, 3.1 to 7.3 months] v 3.0 months [95% CI; 2.7 to 5.5 months]; hazard ratio, 0.65; log-rank P = .04; maximum efficiency robust test P = .039). Median overall survival was 22 months (95% CI, 12.9 months to not reached) with pembrolizumab and 18.7 months (95% CI, 11.4 months to not reached) with placebo. There was no significant interaction between PD-L1 CPS ≥ 10 and treatment arm for progression-free survival or overall survival. CONCLUSION Switch maintenance pembrolizumab leads to additional objective responses in patients achieving at least stable disease with first-line platinum-based chemotherapy and prolongs progression-free survival in patients with metastatic urothelial cancer.

Background: This phase II trial (Cancer and Leukemia Group B 90102) sought to determine the efficacy of cisplatin, standard infusion of gemcitabine and gefitinib in patients with advanced urothelial carcinoma.Patients and methods: Eligible patients had previously untreated measurable disease, Eastern Cooperative Oncology Group (ECOG) performance status of zero to two and creatinine clearance >50 ml/min. Treatment consisted of cisplatin 70 mg/m 2 day 1 and gemcitabine 1000 mg/m 2 on days 1 and 8 given every 3 weeks concurrent with gefitinib 500 mg/day orally for six cycles. Maintenance gefitinib 500 mg/day was continued for responding or stable disease.Results: Fifty-four of 58 patients were assessable. Twelve patients (22%) had node-only disease, and 25 (46%) had an ECOG performance status of zero. There were 23 objective responses for an overall response rate of 42.6% [95% confidence interval (CI) 29.2% to 56.8%]. The median survival time was 15.1 months (95% CI 11.1-21.7 months) and the median time to progression was 7.4 months (95% CI 5.6-9.2 months). Conclusions:The combination of cisplatin, gemcitabine and gefitinib is well tolerated and active in advanced transitional cell carcinoma. The addition of gefitinib does not appear to improve response rate or survival in comparison to historical controls of cisplatin and gemcitabine alone.

A prognostic model that predicts overall survival (OS) for metastatic urothelial cancer (MetUC) patients treated with cisplatin-based chemotherapy was developed, validated, and compared with a commonly used Memorial Sloan-Kettering Cancer Center (MSKCC) risk-score model. Data from 7 protocols that enrolled 308 patients with MetUC were pooled. An external multi-institutional dataset was used to validate the model. The primary measurement of predictive discrimination was Harrell's c-index, computed with 95% confidence interval (CI). The final model included four pretreatment variables to predict OS: visceral metastases, albumin, performance status, and hemoglobin. The Harrell's c-index was 0.67 for the four-variable model and 0.64 for the MSKCC risk-score model, with a prediction improvement for OS (the U statistic and its standard deviation were used to calculate the two-sided P = .002). In the validation cohort, the c-indices for the four-variable and the MSKCC risk-score models were 0.63 (95% CI = 0.56 to 0.69) and 0.58 (95% CI = 0.52 to 0.65), respectively, with superiority of the four-variable model compared with the MSKCC risk-score model for OS (the U statistic and its standard deviation were used to calculate the two-sided P = .02).