A phase 2 trial of buparlisib in patients with platinum-resistant metastatic urothelial carcinoma.

BACKGROUND: The phosphatidyl 3-inositol kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR) pathway frequently is activated in patients with urothelial carcinoma (UC). In the current study, the authors performed a phase 2 study evaluating the efficacy of the pan-isoform class I PI3K inhibitor buparlisib in patients with platinum-refractory metastatic UC. METHODS: Two cohorts were recruited: an initial genetically unselected cohort and a subsequent expansion cohort of patients with PI3K/Akt/mTOR pathway-altered tumors. The primary endpoint was the 2-month progression-free survival rate. A rate of ≥80% was considered promising using a Simon 2-stage minimax design. Secondary endpoints included safety and correlation of markers of PI3K pathway activation with outcome. RESULTS: Six of 13 evaluable patients within the initial cohort demonstrated stable disease and 1 demonstrated a partial response, which was below the cutoff of 9 patients required to proceed to stage 2. Three of the patients with stable disease and the patient with a partial response harbored somatic TSC1 alterations. Four patients subsequently were recruited onto an expansion cohort: 3 patients with TSC1 alterations and 1 patient with a PIK3CA-activating mutation. No patient achieved disease control at 8 weeks and accrual was halted. Of the 19 patients evaluable for toxicity, 17 demonstrated treatment-related toxicities, 2 of whom had to discontinue therapy. CONCLUSIONS: Buparlisib was found to demonstrate modest activity in patients with metastatic UC whose tumors harbored TSC1 loss of function alterations; however, this was not a robust predictor of response to buparlisib. The pattern of genetic coalterations likely influences drug sensitivity. Given the modest clinical activity and substantial toxicity of buparlisib, future trials of PI3K inhibitors in patients with UC should focus on isoform-selective PI3K inhibitors in genomically selected patients. LAY SUMMARY: The phosphatidyl 3-inositol kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR) signaling pathway frequently is upregulated in patients with metastatic urothelial carcinoma (UC). This trial explored buparlisib, an inhibitor of the pathway, in patients with heavily pretreated metastatic UC. Although the drug was found to have modest efficacy, with 6 patients experiencing stable disease and 1 patient achieving a partial response at 8 weeks on therapy, significant side effects also were observed. Patients with specific genetic alterations responded to treatment. Further studies of PI3K pathway inhibition are warranted using newer agents that have superior toxicity profiles and are more selective inhibitors of the pathway.

Real-world progression, treatment, and survival outcomes during rapid adoption of immunotherapy for advanced non-small cell lung cancer.

BACKGROUND: Despite the rapid adoption of immunotherapies in advanced non-small cell lung cancer (advNSCLC), knowledge gaps remain about their real-world (rw) performance. METHODS: This retrospective, observational, multicenter analysis used the Flatiron Health deidentified electronic health record-derived database of rw patients with advNSCLC who received treatment with PD-1 and/or PD-L1 (PD-[L]1) inhibitors before July 1, 2017 (N = 5257) and had ≥6 months of follow-up. The authors investigated PD-(L)1 line of treatment and PD-L1 testing rates and the relationship between overall survival (OS) and rw intermediate endpoints: progression-free survival (rwPFS), rw time to progression (rwTTP), rw time to next treatment (rwTTNT), and rw time to discontinuation (rwTTD). RESULTS: First-line PD-(L)1 inhibitor use increased from 0% (in the third quarter of 2014 [Q3 2014]) to 42% (Q2 2017) over the study period. PD-L1 testing also increased (from 3% in Q3 2015 to 70% in Q2 2017). The estimated median OS was 9.3 months (95% CI, 8.9-9.8 months), and the estimated rwPFS was 3.2 months (95% CI, 3.1-3.3 months). Longer OS and rwPFS were associated with ≥50% PD-L1 percentage staining results. Correlations (⍴) between OS and intermediate endpoints were ⍴ = 0.75 (95% CI, 0.73-0.76) for rwPFS and ⍴ = 0.60 (95% CI, 0.57-0.63) for rwTTP, and, for treatment-based intermediate endpoints, correlations were ⍴ = 0.60 (95% CI, 0.56-0.64) for rwTTNT (N = 856) and ⍴ = 0.81 (95% CI, 0.80-0.82) for rwTTD. CONCLUSIONS: The use of first-line PD-(L)1 inhibitors and PD-L1 testing has substantially increased, with better outcomes for patients who have ≥50% PD-L1 percentage staining. Intermediate rw tumor-dynamics estimates were moderately correlated with OS in patients with advNSCLC who received immunotherapy, highlighting the need for optimizing and standardizing rw endpoints to enhance the understanding of patient outcomes outside clinical trials.

Contribution of systemic and somatic factors to clinical response and resistance to PD-L1 blockade in urothelial cancer: An exploratory multi-omic analysis.

BACKGROUND: Inhibition of programmed death-ligand 1 (PD-L1) with atezolizumab can induce durable clinical benefit (DCB) in patients with metastatic urothelial cancers, including complete remissions in patients with chemotherapy refractory disease. Although mutation load and PD-L1 immune cell (IC) staining have been associated with response, they lack sufficient sensitivity and specificity for clinical use. Thus, there is a need to evaluate the peripheral blood immune environment and to conduct detailed analyses of mutation load, predicted neoantigens, and immune cellular infiltration in tumors to enhance our understanding of the biologic underpinnings of response and resistance. METHODS AND FINDINGS: The goals of this study were to (1) evaluate the association of mutation load and predicted neoantigen load with therapeutic benefit and (2) determine whether intratumoral and peripheral blood T cell receptor (TCR) clonality inform clinical outcomes in urothelial carcinoma treated with atezolizumab. We hypothesized that an elevated mutation load in combination with T cell clonal dominance among intratumoral lymphocytes prior to treatment or among peripheral T cells after treatment would be associated with effective tumor control upon treatment with anti-PD-L1 therapy. We performed whole exome sequencing (WES), RNA sequencing (RNA-seq), and T cell receptor sequencing (TCR-seq) of pretreatment tumor samples as well as TCR-seq of matched, serially collected peripheral blood, collected before and after treatment with atezolizumab. These parameters were assessed for correlation with DCB (defined as progression-free survival [PFS] >6 months), PFS, and overall survival (OS), both alone and in the context of clinical and intratumoral parameters known to be predictive of survival in this disease state. Patients with DCB displayed a higher proportion of tumor-infiltrating T lymphocytes (TIL) (n = 24, Mann-Whitney p = 0.047). Pretreatment peripheral blood TCR clonality below the median was associated with improved PFS (n = 29, log-rank p = 0.048) and OS (n = 29, log-rank p = 0.011). Patients with DCB also demonstrated more substantial expansion of tumor-associated TCR clones in the peripheral blood 3 weeks after starting treatment (n = 22, Mann-Whitney p = 0.022). The combination of high pretreatment peripheral blood TCR clonality with elevated PD-L1 IC staining in tumor tissue was strongly associated with poor clinical outcomes (n = 10, hazard ratio (HR) (mean) = 89.88, HR (median) = 23.41, 95% CI [2.43, 506.94], p(HR > 1) = 0.0014). Marked variations in mutation loads were seen with different somatic variant calling methodologies, which, in turn, impacted associations with clinical outcomes. Missense mutation load, predicted neoantigen load, and expressed neoantigen load did not demonstrate significant association with DCB (n = 25, Mann-Whitney p = 0.22, n = 25, Mann-Whitney p = 0.55, and n = 25, Mann-Whitney p = 0.29, respectively). Instead, we found evidence of time-varying effects of somatic mutation load on PFS in this cohort (n = 25, p = 0.044). A limitation of our study is its small sample size (n = 29), a subset of the patients treated on IMvigor 210 (NCT02108652). Given the number of exploratory analyses performed, we intend for these results to be hypothesis-generating. CONCLUSIONS: These results demonstrate the complex nature of immune response to checkpoint blockade and the compelling need for greater interrogation and data integration of both host and tumor factors. Incorporating these variables in prospective studies will facilitate identification and treatment of resistant patients.

Multicenter Prospective Phase II Trial of Neoadjuvant Dose-Dense Gemcitabine Plus Cisplatin in Patients With Muscle-Invasive Bladder Cancer.

Purpose Neoadjuvant chemotherapy followed by radical cystectomy (RC) is a standard of care for the management of muscle-invasive bladder cancer (MIBC). Dose-dense cisplatin-based regimens have yielded favorable outcomes compared with standard-dose chemotherapy, yet the optimal neoadjuvant regimen remains undefined. We assessed the efficacy and tolerability of six cycles of neoadjuvant dose-dense gemcitabine and cisplatin (ddGC) in patients with MIBC. Patients and Methods In this prospective, multicenter phase II study, patients received ddGC (gemcitabine 2,500 mg/m2 on day 1 and cisplatin 35 mg/m2 on days 1 and 2) every 2 weeks for 6 cycles followed by RC. The primary end point was pathologic downstaging to non-muscle-invasive disease (< pT2N0). Patients who did not undergo RC were deemed nonresponders. Pretreatment tumors underwent next-generation sequencing to identify predictors of chemosensitivity. Results Forty-nine patients were enrolled from three institutions. The primary end point was met, with 57% of 46 evaluable patients downstaged to < pT2N0. Pathologic response correlated with improved recurrence-free survival and overall survival. Nineteen patients (39%) required toxicity-related dose modifications. Sixty-seven percent of patients completed all six planned cycles. No patient failed to undergo RC as a result of chemotherapy-associated toxicities. The most frequent treatment-related toxicity was anemia (12%; grade 3). The presence of a presumed deleterious DNA damage response (DDR) gene alteration was associated with chemosensitivity (positive predictive value for < pT2N0 [89%]). No patient with a deleterious DDR gene alteration has experienced recurrence at a median follow-up of 2 years. Conclusion Six cycles of ddGC is an active, well-tolerated neoadjuvant regimen for the treatment of patients with MIBC. The presence of a putative deleterious DDR gene alteration in pretreatment tumor tissue strongly predicted for chemosensitivity, durable response, and superior long-term survival.

DNA Damage Response and Repair Gene Alterations Are Associated with Improved Survival in Patients with Platinum-Treated Advanced Urothelial Carcinoma.

Purpose: Platinum-based chemotherapy remains the standard treatment for advanced urothelial carcinoma by inducing DNA damage. We hypothesize that somatic alterations in DNA damage response and repair (DDR) genes are associated with improved sensitivity to platinum-based chemotherapy.Experimental Design: Patients with diagnosis of locally advanced and metastatic urothelial carcinoma treated with platinum-based chemotherapy who had exon sequencing with the Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) assay were identified. Patients were dichotomized based on the presence/absence of alterations in a panel of 34 DDR genes. DDR alteration status was correlated with clinical outcomes and disease features.Results: One hundred patients were identified, of which 47 harbored alterations in DDR genes. Patients with DDR alterations had improved progression-free survival (9.3 vs. 6.0 months, log-rank P = 0.007) and overall survival (23.7 vs. 13.0 months, log-rank P = 0.006). DDR alterations were also associated with higher number mutations and copy-number alterations. A trend toward positive correlation between DDR status and nodal metastases and inverse correlation with visceral metastases were observed. Different DDR pathways also suggested variable impact on clinical outcomes.Conclusions: Somatic DDR alteration is associated with improved clinical outcomes in platinum-treated patients with advanced urothelial carcinoma. Once validated, it can improve patient selection for clinical practice and future study enrollment. Clin Cancer Res; 23(14); 3610-8. ©2017 AACR.

Phase I Study of Everolimus in Combination with Gemcitabine and Split-Dose Cisplatin in Advanced Urothelial Carcinoma.

BACKGROUND: Cisplatin-based combination chemotherapy is standard first-line treatment for patients with advanced urothelial carcinoma (UC). Molecular profiling studies reveal that the PI3K/AKT/mTOR pathway is altered in a significant percentage of UCs. OBJECTIVE: We conducted a phase I trial to evaluate the feasibility of combining the mTOR inhibitor everolimus with gemcitabine and split-dose cisplatin (GC) in advanced UC in the first-line setting. METHODS: Patients received gemcitabine 800 mg/m2 and cisplatin 35 mg/m2 on days 1 and 8 of 21-day cycles for a total of 6 cycles in combination with everolimus at increasing dose levels (DL1:5 mg QOD, DL2:5 mg daily, DL3:10 mg daily) following a standard 3+3 design. Responses were assessed every 2 cycles. Patients with at least stable disease (SD) continued everolimus until progression. Goals were to establish dose-limiting toxicities (DLTs) and maximum tolerated dose (MTD) for the combination. RESULTS: 12 patients were enrolled, 3 at DL1, 3 at DL2, and an additional 6 at DL1 *(DL1 following de-escalation). 3/3 patients at DL2 had DLTs during cycle 1. 2/8 evaluable patients at DL1/DL1 * had DLTs during cycle 1. DLTs were primarily hematologic. Further toxicities, also primarily hematologic, were observed during later treatment cycles, leading to 8 chemotherapy dose reductions overall. Partial responses were observed in 4/10 evaluable patients, and SD in 5/10. Median overall survival was 10.8 months (95% CI 6.9, not reached). CONCLUSIONS: The maximum tolerated dose was reached at the lowest dose level, 5 mg QOD, for everolimus in combination with gemcitabine and split-dose cisplatin in advanced UC. The regimen was limited by hematologic toxicity.