Summary Background Patients with metastatic urothelial carcinoma have limited treatment options after failure of platinum-based chemotherapy. This multicenter, single-arm phase 2 trial evaluated atezolizumab, an engineered humanized IgG1 monoclonal antibody that binds selectively to programmed death–ligand 1 (PD-L1), in this population. Methods Three hundred and ten patients received atezolizumab (1200 mg, every 3 weeks). PD-L1 expression on tumor-infiltrating immune cells (IC) was prospectively assessed by immunohistochemistry. The co-primary endpoints were the objective response rate by RECIST v1.1 and immune modified RECIST. A hierarchical testing procedure was used to test whether the objective response rate was significantly higher than the historical control of 10% at alpha level of 0·05. Exploratory analyses included assessing the association between The Cancer Genome Atlas (TCGA) molecular subtypes, CD8+ T cell infiltration, mutation load, and clinical outcomes. Findings By independent review, objective response rates were 26% (95% CI 18 to 36) in the IC2/3 group, 18% (95% CI 13 to 24) in the IC1/2/3 group and 15% (95% CI 11 to 19) in all patients. With a median follow-up of 11·7 months, ongoing responses were observed in 84% of responders. The median duration of response was not reached (range 2·0*, 13·7* months, *censored). The median overall survival was 11·4 months (95% CI 9·0 to not estimable) in the IC2/3 group, 8·8 months (95% CI 7·1 to 10·6) in the IC1/2/3, and 7·9 months (95% CI 6·6 to 9·3) in all patients. Grade 3–4 related treatment-related adverse events occurred in 16% and grade 3–4 immune-mediated adverse events occurred in 5% of treated patients. Exploratory analyses showed TCGA subtypes and mutation load to be independently predictive for response to atezolizumab. Interpretation Atezolizumab demonstrated durable activity and good tolerability in this population. PD-L1 expression on immune cells was associated with response. This is the first report to show the association of TCGA subtypes with response to immune checkpoint inhibition and demonstrate the importance of mutation load as a biomarker of response to this class of agents in advanced urothelial carcinoma. Funding F. Hoffmann-La Roche Ltd.

Summary Background First-line chemotherapy for patients with cisplatin-ineligible locally-advanced or metastatic urothelial carcinoma (mUC) is associated with short response duration, poor survival, and high toxicity. This multicenter, 2-cohort phase 2 study evaluated atezolizumab (anti–programmed death-ligand 1 [PD-L1]) as treatment for mUC in this setting, as well as in later lines. Methods In a cohort of previously untreated patients who were cisplatin ineligible, atezolizumab was given 1200 mg every 3 weeks until progression. The primary endpoint was independently confirmed objective response rate per Response Evaluation Criteria In Solid Tumors v1.1 (central review), evaluated in pre-specified subgroups based on PD-L1 expression and in all patients. Secondary endpoints included response duration, progression-free survival, overall survival, and safety. Exploratory analyses included biomarker correlates of response and survival. This study is registered with ClinicalTrials.gov, number NCT02108652. Findings Of 119 patients who received atezolizumab in the first-line setting, 83 (70%) had baseline renal impairment, and 24 (20%) had Eastern Cooperative Oncology Group performance status 2. At 17·2 months’ median follow-up, the objective response rate was 23% (95% CI 16–31), the complete response rate was 9%, and 19 of 27 responses were ongoing. Median response duration was not reached. Responses occurred across all PD-L1 and poor prognostic factor subgroups. Median progression-free survival was 2·7 months. Median overall survival was 15·9 months. Tumour mutation load was associated with response. Treatment-related adverse events ≥10% were fatigue, diarrhoea, and pruritus. One treatment-related death (sepsis) occurred. Nine patients (8%) had an adverse event leading to treatment discontinuation. Immune-mediated events occurred in 14 (12%) patients. Interpretation Atezolizumab demonstrated encouraging durable response rates, survival, and tolerability, supporting its therapeutic use in untreated mUC. Funding F. Hoffmann-La Roche Ltd./Genentech, Inc., a member of the Roche Group.

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PURPOSE Locally advanced or metastatic urothelial carcinoma is an incurable disease with limited treatment options, especially for patients who were previously treated with platinum and anti–programmed death 1 or anti–programmed death ligand 1 (PD-1/L1) therapy. Enfortumab vedotin is an antibody–drug conjugate that targets Nectin-4, which is highly expressed in urothelial carcinoma. METHODS EV-201 is a global, phase II, single-arm study of enfortumab vedotin 1.25 mg/kg (intravenously on days 1, 8, and 15 of every 28-day cycle) in patients with locally advanced or metastatic urothelial carcinoma who were previously treated with platinum chemotherapy and anti–PD-1/L1 therapy. The primary end point was objective response rate per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 by blinded independent central review. Key secondary end points were duration of response, progression-free survival, overall survival, safety, and tolerability. RESULTS Enfortumab vedotin was administered to 125 patients with metastatic urothelial carcinoma. Median follow-up was 10.2 months (range, 0.5 to 16.5 months). Confirmed objective response rate was 44% (95% CI, 35.1% to 53.2%), including 12% complete responses. Similar responses were observed in prespecified subgroups, such as those patients with liver metastases and those with no response to prior anti–PD-1/L1 therapy. Median duration of response was 7.6 months (range, 0.95 to 11.30+ months). The most common treatment-related adverse events were fatigue (50%), any peripheral neuropathy (50%), alopecia (49%), any rash (48%), decreased appetite (44%), and dysgeusia (40%). No single treatment-related adverse events grade 3 or greater occurred in 10% or more of patients. CONCLUSION Enfortumab vedotin demonstrated a clinically meaningful response rate with a manageable and tolerable safety profile in patients with locally advanced or metastatic urothelial carcinoma who were previously treated with platinum and anti–PD-1/L1 therapies.

Immunotherapy has moved to the center stage of cancer treatment with the recent success of trials in solid tumors with PD-1/PD-L1 axis blockade. Programmed death-1 or PD-1 is a checkpoint molecule on T cells that plays a vital role in limiting adaptive immune responses and preventing autoimmune and auto-inflammatory reactivity in the normal host. In cancer patients, PD-1 expression is very high on T cells in the tumor microenvironment, and PD-L1, its primary ligand, is variably expressed on tumor cells and antigen-presenting cells within tumors, providing a potent inhibitory influence within the tumor microenvironment. While PD-L1 expression on tumors is often regarded as a negative prognostic factor, it is clearly associated with a positive outcome for treatment with PD-1/PD-L1 blocking antibodies, and has been used to select patients for this therapy. Responses of long duration, a minority of patients with atypical responses in which progression may precede tumor shrinkage, and a pattern of autoimmune side effects often seen with this class of drugs characterize therapy with PD-1/PD-L1 blocking drugs. While excellent efficacy has been seen with a limited number of tumor types, most epithelial cancers do not show responses of long duration with these agents. In the current review, we will briefly summarize the scientific background data supporting the development of PD-1/PD-L1 blockade, and then describe the track record of these antibodies in multiple different histologies ranging from melanoma and lung cancer to less common tumor types as well as discuss biomarkers that may assist in patient selection.

PURPOSE Patients with metastatic urothelial carcinoma (mUC) who progress on platinum-based combination chemotherapy (PLT) and checkpoint inhibitors (CPIs) have limited options that offer objective response rates (ORRs) of approximately 10% with a median overall survival (OS) of 7-8 months. Sacituzumab govitecan (SG) is a TROP-2–directed antibody-drug conjugate with an SN-38 payload that has shown preliminary activity in mUC. METHODS TROPHY-U-01 (ClinicalTrials.gov identifier: NCT03547973 ) is a multicohort, open-label, phase II, registrational study. Cohort 1 includes patients with locally advanced or unresectable or mUC who had progressed after prior PLT and CPI. Patients received SG 10 mg/kg on days 1 and 8 of 21-day cycles. The primary outcome was centrally reviewed ORR; secondary outcomes were progression-free survival, OS, duration of response, and safety. RESULTS Cohort 1 included 113 patients (78% men; median age, 66 years; 66.4% visceral metastases; median of three [range, 1-8] prior therapies). At a median follow-up of 9.1 months, the ORR was 27% (31 of 113; 95% CI, 19.5 to 36.6); 77% had decrease in measurable disease. Median duration of response was 7.2 months (95% CI, 4.7 to 8.6 months), with median progression-free survival and OS of 5.4 months (95% CI, 3.5 to 7.2 months) and 10.9 months (95% CI, 9.0 to 13.8 months), respectively. Key grade ≥ 3 treatment-related adverse events included neutropenia (35%), leukopenia (18%), anemia (14%), diarrhea (10%), and febrile neutropenia (10%), with 6% discontinuing treatment because of treatment-related adverse events. CONCLUSION SG is an active drug with a manageable safety profile with most common toxicities of neutropenia and diarrhea. SG has notable efficacy compared with historical controls in pretreated mUC that has progressed on both prior PLT regimens and CPI. The results from this study supported accelerated approval of SG in this population.

A B S T R A C T PurposeWe sought to define the prevalence and co-occurrence of actionable genomic alterations in patients with high-grade bladder cancer to serve as a platform for therapeutic drug discovery. Patients and MethodsAn integrative analysis of 97 high-grade bladder tumors was conducted to identify actionable drug targets, which are defined as genomic alterations that have been clinically validated in another cancer type (eg, BRAF mutation) or alterations for which a selective inhibitor of the target or pathway is under clinical investigation. DNA copy number alterations (CNAs) were defined by using array comparative genomic hybridization. Mutation profiling was performed by using both mass spectroscopy-based genotyping and Sanger sequencing. ResultsSixty-one percent of tumors harbored potentially actionable genomic alterations. A core pathway analysis of the integrated data set revealed a nonoverlapping pattern of mutations in the RTK-RAS-RAF and phosphoinositide 3-kinase/AKT/mammalian target of rapamycin pathways and regulators of G 1 -S cell cycle progression. Unsupervised clustering of CNAs defined two distinct classes of bladder tumors that differed in the degree of their CNA burden. Integration of mutation and copy number analyses revealed that mutations in TP53 and RB1 were significantly more common in tumors with a high CNA burden (P Ͻ .001 and P Ͻ .003, respectively). ConclusionHigh-grade bladder cancer possesses substantial genomic heterogeneity. The majority of tumors harbor potentially tractable genomic alterations that may predict for response to target-selective agents. Given the genomic diversity of bladder cancers, optimal development of target-specific agents will require pretreatment genomic characterization.

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