Randomized Phase II Study Evaluating the Addition of Pembrolizumab to Radium-223 in Metastatic Castration-resistant Prostate Cancer.

The checkpoint immunotherapeutic pembrolizumab induces responses in a small minority of patients with metastatic castration-resistant prostate cancer (mCRPC). Radium-223 (R223) may increase immunogenicity of bone metastases and increase pembrolizumab (P) activity. In a randomized phase II study, we assessed the effect of R223+P compared with R223 on tumor immune infiltration, safety, and clinical outcomes in patients with mCRPC. The primary endpoint was differences in CD4+ and CD8+ T-cell infiltrate in 8-week versus baseline bone metastasis biopsies; secondary endpoints were safety, radiographic progression-free survival (rPFS), and overall survival (OS). Of the 42 treated patients (29 R223+P, 13 R223), 18 R223+P and 8 R223 patients had evaluable paired tumor biopsies. Median fold-change of CD4+ T cells was -0.7 (range: -9.3 to 4.7) with R223+P and 0.1 (-11.1 to 3.7) with R223 (P = 0.66); for CD8+ T cells, median fold-change was -0.6 (-7.4 to 5.3) with R223+P and -1.3 (-3.1 to 4.8) with R223 (P = 0.66). Median rPFS and OS was 6.1 (95% confidence interval: 2.7-11.0) and 16.9 months [12.7-not reached (NR)], respectively, with R223+P and 5.7 (2.6-NR) and 16.0 (9.0-NR), respectively, with R223. Although R223+P was well tolerated with no unexpected toxicity, the combination did not improve efficacy. High-dimensional flow cytometry demonstrated minimal immune modulation with R223, whereas R223+P induced CTLA-4 expression on circulating CD4+ T cells. Clinical responders possessed lower circulating frequencies of Ki67+ T and myeloid cells at baseline and higher circulating frequencies of TIM-3+ T and myeloid cells by week 9. Although R223+P did not induce T-cell infiltration into the tumor microenvironment, exhaustion of induced peripheral T-cell immune responses may dampen the combination's clinical activity.

Circulating and Intratumoral Immune Determinants of Response to Atezolizumab plus Bevacizumab in Patients with Variant Histology or Sarcomatoid Renal Cell Carcinoma.

Renal cell carcinoma (RCC) of variant histology comprises approximately 20% of kidney cancer diagnoses, yet the optimal therapy for these patients and the factors that impact immunotherapy response remain largely unknown. To better understand the determinants of immunotherapy response in this population, we characterized blood- and tissue-based immune markers for patients with variant histology RCC, or any RCC histology with sarcomatoid differentiation, enrolled in a phase II clinical trial of atezolizumab and bevacizumab. Baseline circulating (plasma) inflammatory cytokines were highly correlated with one another, forming an "inflammatory module" that was increased in International Metastatic RCC Database Consortium poor-risk patients and was associated with worse progression-free survival (PFS; P = 0.028). At baseline, an elevated circulating vascular endothelial growth factor A (VEGF-A) level was associated with a lack of response (P = 0.03) and worse PFS (P = 0.021). However, a larger increase in on-treatment levels of circulating VEGF-A was associated with clinical benefit (P = 0.01) and improved overall survival (P = 0.0058). Among peripheral immune cell populations, an on-treatment decrease in circulating PD-L1+ T cells was associated with improved outcomes, with a reduction in CD4+PD-L1+ [HR, 0.62; 95% confidence interval (CI), 0.49-0.91; P = 0.016] and CD8+PD-L1+ T cells (HR, 0.59; 95% CI, 0.39-0.87; P = 0.009) correlated with improved PFS. Within the tumor itself, a higher percentage of terminally exhausted (PD-1+ and either TIM-3+ or LAG-3+) CD8+ T cells was associated with worse PFS (P = 0.028). Overall, these findings support the value of tumor and blood-based immune assessments in determining therapeutic benefit for patients with RCC receiving atezolizumab plus bevacizumab and provide a foundation for future biomarker studies for patients with variant histology RCC receiving immunotherapy-based combinations.

Metastatic renal cell carcinoma to the pancreas and other sites-a multicenter retrospective study.

Background: Metastatic renal cell carcinoma (mRCC) is a heterogenous disease with poor 5-year overall survival (OS) at 14%. Patients with mRCC to endocrine organs historically have prolonged OS. Pancreatic metastases are uncommon overall, with mRCC being the most common etiology of pancreatic metastases. In this study, we report the long-term outcomes of patients with mRCC to the pancreas in two separate cohorts. Methods: We performed a multicenter, international retrospective cohort study of patients with mRCC to the pancreas at 15 academic centers. Cohort 1 included 91 patients with oligometastatic disease to the pancreas. Cohort 2 included 229 patients with multiples organ sites of metastases including the pancreas. The primary endpoint for Cohorts 1 and 2 was median OS from time of metastatic disease in the pancreas until death or last follow up. Findings: In Cohort 1, the median OS (mOS) was 121 months with a median follow up time of 42 months. Patients who underwent surgical resection of oligometastatic disease had mOS of 100 months with a median follow-up time of 52.5 months. The mOS for patients treated with systemic therapy was not reached. In Cohort 2, the mOS was 90.77 months. Patients treated with first-line (1L) VEGFR therapy had mOS of 90.77 months; patients treated with IL immunotherapy (IO) had mOS of 92 months; patients on 1L combination VEGFR/IO had mOS of 74.9 months. Interpretations: This is the largest retrospective cohort of mRCC involving the pancreas. We confirmed the previously reported long-term outcomes in patients with oligometastatic pancreas disease and demonstrated prolonged survival in patients with multiple RCC metastases that included the pancreas. In this retrospective study with heterogeneous population treated over 2 decades, mOS was similar when stratified by first-line therapy. Future research will be needed to determine whether mRCC patients with pancreatic metastases require a different initial treatment strategy. Funding: Statistical analyses for this study were supported in part by the University of Colorado Cancer Center Support Grant from the NIH/NCI, P30CA046934-30.

Clinical Activity and Safety of Cabozantinib for Brain Metastases in Patients With Renal Cell Carcinoma.

IMPORTANCE: Patients with brain metastases from renal cell carcinoma (RCC) have been underrepresented in clinical trials, and effective systemic therapy is lacking. Cabozantinib shows robust clinical activity in metastatic RCC, but its effect on brain metastases remains unclear. OBJECTIVE: To assess the clinical activity and toxic effects of cabozantinib to treat brain metastases in patients with metastatic RCC. DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study included patients with metastatic RCC and brain metastases treated in 15 international institutions (US, Belgium, France, and Spain) between January 2014 and October 2020. Cohort A comprised patients with progressing brain metastases without concomitant brain-directed local therapy, and cohort B comprised patients with stable or progressing brain metastases concomitantly treated by brain-directed local therapy. EXPOSURES: Receipt of cabozantinib monotherapy at any line of treatment. MAIN OUTCOMES AND MEASURES: Intracranial radiological response rate by modified Response Evaluation Criteria in Solid Tumors, version 1.1, and toxic effects of cabozantinib. RESULTS: Of the 88 patients with brain metastases from RCC included in the study, 33 (38%) were in cohort A and 55 (62%) were in cohort B; the majority of patients were men (n = 69; 78%), and the median age at cabozantinib initiation was 61 years (range, 34-81 years). Median follow-up was 17 months (range, 2-74 months). The intracranial response rate was 55% (95% CI, 36%-73%) and 47% (95% CI, 33%-61%) in cohorts A and B, respectively. In cohort A, the extracranial response rate was 48% (95% CI, 31%-66%), median time to treatment failure was 8.9 months (95% CI, 5.9-12.3 months), and median overall survival was 15 months (95% CI, 9.0-30.0 months). In cohort B, the extracranial response rate was 38% (95% CI, 25%-52%), time to treatment failure was 9.7 months (95% CI, 6.0-13.2 months), and median overall survival was 16 months (95% CI, 12.0-21.9 months). Cabozantinib was well tolerated, with no unexpected toxic effects or neurological adverse events reported. No treatment-related deaths were observed. CONCLUSIONS AND RELEVANCE: In this cohort study, cabozantinib showed considerable intracranial activity and an acceptable safety profile in patients with RCC and brain metastases. Support of prospective studies evaluating the efficacy of cabozantinib for brain metastases in patients with RCC is critical.

Efficacy of Platinum Rechallenge in Metastatic Urothelial Carcinoma After Previous Platinum-Based Chemotherapy for Metastatic Disease.

BACKGROUND: Fit patients with metastatic urothelial carcinoma (mUC) receive first-line platinum-based combination chemotherapy (fPBC) as standard of care and may receive additional later-line chemotherapy after progression. Our study compares outcomes with subsequent platinum-based chemotherapy (sPBC) versus subsequent non-platinum-based chemotherapy (sNPBC). MATERIALS AND METHODS: Patients from 27 international centers in the Retrospective International Study of Cancers of the Urothelium (RISC) who received fPBC for mUC and at least two cycles of subsequent chemotherapy were included in this study. A multivariable Cox proportional hazards model compared overall survival (OS) and progression-free survival (PFS). RESULTS: One hundred thirty-five patients received sPBC and 161 received sNPBC. Baseline characteristics were similar between groups, except patients who received sPBC had higher baseline hemoglobin, higher disease control rate with fPBC, and longer time since fPBC. OS was superior in the sPBC group (median 7.9 vs 5.5 months) in a model adjusting for comorbidity burden, performance status, liver metastases, number of fPBC cycles received, best response to fPBC, and time since fPBC (hazard ratio, 0.72; 95% confidence interval, 0.53-0.98; p = .035). There was no difference in PFS. More patients in the sPBC group achieved disease control than in the sNPBC group (57.4% vs 44.8%; p = .041). Factors associated with achieving disease control in the sPBC group but not the sNPBC group included longer time since fPBC, achieving disease control with fPBC, and absence of liver metastases. CONCLUSION: After receiving fPBC for mUC, patients who received sPBC had better OS and disease control. This may help inform the choice of subsequent chemotherapy in patients with mUC. IMPLICATIONS FOR PRACTICE: Patients with progressive metastatic urothelial carcinoma after first-line platinum-based combination chemotherapy may now receive immuno-oncology agents, erdafitinib, enfortumab vedotin, or sacituzumab govitecan-hziy; however, those ineligible for these later-line therapies or who progress after receiving them may be considered for subsequent chemotherapy. In this retrospective study of 296 patients, survival outcomes and disease control rates were better in those receiving subsequent platinum-based rechallenge compared with non-platinum-based chemotherapy, suggesting that patients should receive platinum rechallenge if clinically able. Disease control with platinum rechallenge was more likely with prior first-line platinum having achieved disease control, longer time since first-line platinum, and absence of liver metastases.

Association of Concomitant Bone Resorption Inhibitors With Overall Survival Among Patients With Metastatic Castration-Resistant Prostate Cancer and Bone Metastases Receiving Abiraterone Acetate With Prednisone as First-Line Therapy.

Importance: Bone resorption inhibitors (BRIs) are recommended by international guidelines to prevent skeletal-related events (SREs) among patients with metastatic castration-resistant prostate cancer (mCRPC) and bone metastases. Abiraterone acetate with prednisone is currently the most common first-line therapy for the treatment of patients with mCRPC; however, the clinical impact of the addition of BRIs to abiraterone acetate with prednisone in this disease setting is unknown. Objective: To evaluate the association of the use of concomitant BRIs with overall survival (OS) and time to first SRE among patients with mCRPC and bone metastases receiving abiraterone acetate with prednisone as first-line therapy. Design, Setting, and Participants: This retrospective cohort study collected data from 745 consecutive patients who began receiving abiraterone acetate with prednisone as first-line therapy for mCRPC with bone metastases between January 1, 2013, and December 31, 2016. Data were collected from 8 hospitals in Canada, Europe, and the US from June 15 to September 15, 2019. Exposures: Patients were classified by receipt vs nonreceipt of concomitant BRIs and subclassified by volume of disease (high volume or low volume, using definitions from the Chemohormonal Therapy Vs Androgen Ablation Randomized Trial for Extensive Disease in Prostate Cancer [CHAARTED] E3805 study) at the initiation of abiraterone acetate with prednisone therapy. Main Outcomes and Measures: The primary end point was OS. The secondary end point was time to first SRE. The Kaplan-Meier method and Cox proportional hazards models were used. Results: Of the 745 men (median age, 77.6 years [interquartile range, 68.1-83.6 years]; 699 White individuals [93.8%]) included in the analysis, 529 men (71.0%) received abiraterone acetate with prednisone alone (abiraterone acetate cohort), and 216 men (29.0%) received abiraterone acetate with prednisone plus BRIs (BRI cohort). A total of 420 men (56.4%) had high-volume disease, and 276 men (37.0%) had low-volume disease. The median follow-up was 23.5 months (95% CI, 19.8-24.9 months). Patients in the BRI cohort experienced significantly longer OS compared with those in the abiraterone acetate cohort (31.8 vs 23.0 months; hazard ratio [HR], 0.65; 95% CI, 0.54-0.79; P < .001). The OS benefit in the BRI cohort was greater for patients with high-volume vs low-volume disease (33.6 vs 19.7 months; HR, 0.51; 95% CI, 0.38-0.68; P < .001). The BRI cohort also had a significantly shorter time to first SRE compared with the abiraterone acetate cohort (32.4 vs 42.7 months; HR, 1.27; 95% CI, 1.00-1.60; P = .04), and the risk of a first SRE was more than double in the subgroup with low-volume disease (HR, 2.29; 95% CI, 1.57-3.35; P < .001). In the multivariable analysis, concomitant BRIs use was independently associated with longer OS (HR, 0.64; 95% CI, 0.52-0.79; P < .001). Conclusions and Relevance: In this study, the addition of BRIs to abiraterone acetate with prednisone as first-line therapy for the treatment of patients with mCRPC and bone metastases was associated with longer OS, particularly in patients with high-volume disease. These results suggest that the use of BRIs in combination with abiraterone acetate with prednisone as first-line therapy for the treatment of mCRPC with bone metastases could be beneficial.

Safety and Clinical Activity of Atezolizumab in Patients with Metastatic Castration-Resistant Prostate Cancer: A Phase I Study.

PURPOSE: Atezolizumab [anti-programmed death-ligand 1 (anti-PD-L1)] is well tolerated and efficacious in multiple cancers, but has not been previously evaluated in metastatic castration-resistant prostate cancer (mCRPC). This study examined the safety, efficacy, and biomarkers of atezolizumab monotherapy for mCRPC. PATIENTS AND METHODS: This phase Ia, open-label, dose-escalation and dose-expansion study (PCD4989g) enrolled patients with mCRPC who had progressed on sipuleucel-T or enzalutamide. Atezolizumab was given intravenously every 3 weeks until confirmed disease progression or loss of clinical benefit. Prespecified endpoints included safety, efficacy, biomarker analyses, and radiographic assessments. RESULTS: All 35 evaluable patients [median age, 68 years (range, 45-83 years)] received atezolizumab after ≥1 prior line of therapy; 62.9% of patients had received ≥3 prior lines. Treatment-related adverse events occurred in 21 patients (60.0%), with no deaths. One patient had a confirmed partial response (PR) per RECIST 1.1, and 1 patient had a PR per immune-related response criteria. The confirmed 50% PSA response rate was 8.6% (3 patients). Median overall survival (OS) was 14.7 months [95% confidence interval (CI): 5.9-not evaluable], with a 1-year OS rate of 52.3% (95% CI: 34-70); 2-year OS was 35.9% (95% CI: 13-59). Median follow-up was 13.0 months (range, 1.2-28.1 months). Biomarker analyses showed that atezolizumab activated immune responses; however, a composite biomarker failed to reveal consistent correlations with efficacy. CONCLUSIONS: Atezolizumab was generally well tolerated in patients with mCRPC, with a safety profile consistent with other tumor types. In heavily pretreated patients, atezolizumab monotherapy demonstrated evidence of disease control; however, its limited efficacy suggests a combination approach may be needed.

Integrative molecular characterization of sarcomatoid and rhabdoid renal cell carcinoma.

Sarcomatoid and rhabdoid (S/R) renal cell carcinoma (RCC) are highly aggressive tumors with limited molecular and clinical characterization. Emerging evidence suggests immune checkpoint inhibitors (ICI) are particularly effective for these tumors, although the biological basis for this property is largely unknown. Here, we evaluate multiple clinical trial and real-world cohorts of S/R RCC to characterize their molecular features, clinical outcomes, and immunologic characteristics. We find that S/R RCC tumors harbor distinctive molecular features that may account for their aggressive behavior, including BAP1 mutations, CDKN2A deletions, and increased expression of MYC transcriptional programs. We show that these tumors are highly responsive to ICI and that they exhibit an immune-inflamed phenotype characterized by immune activation, increased cytotoxic immune infiltration, upregulation of antigen presentation machinery genes, and PD-L1 expression. Our findings build on prior work and shed light on the molecular drivers of aggressivity and responsiveness to ICI of S/R RCC.

Treatment of Metastatic Urothelial Carcinoma After Previous Cisplatin-based Chemotherapy for Localized Disease: A Retrospective Comparison of Different Chemotherapy Regimens.

BACKGROUND: Optimal chemotherapy for patients who received cisplatin for localized urothelial carcinoma (UC) and develop metastatic disease is unclear. We compared the efficacy of platinum-based (PBC) versus non-platinum-based (NPBC) first-line chemotherapy for metastasis. PATIENTS AND METHODS: Data were collected from the Retrospective International Study of Cancers of the Urothelial Tract (RISC), a database of 3024 patients from 28 international academic centers from 2005 to 2012. Patient inclusion criteria included: (1) predominant UC; (2) any primary tumor site; (3) cT2-4, cN0-N2, cM0; (4) prior receipt of perioperative/radiation cisplatin-containing chemotherapy; and (5) receipt of cytotoxic chemotherapy in the first-line metastatic setting. Multivariate Cox proportional hazards models were used to show progression-free survival (PFS) and overall survival (OS) from the first day of chemotherapy for metastatic disease to date of censor. RESULTS: Eligibility criteria was met by 132 patients (n = 74 PBC; n = 58 NPBC). The median OS was 8.13 months (interquartile range, 4.87-16.64 months) and 8.77 months (interquartile range, 4.01-13.49 months) for PBC and NPBC, respectively. Neither OS (hazard ratio [HR], 1.04; 95% confidence interval [CI], 0.64-1.69; P = .87) nor PFS (HR, 0.86; 95% CI, 0.56-1.31; P = .48) differed for PBC versus NPBC. However, for patients who received chemotherapy more than a year after perioperative/radiation chemotherapy, OS was superior for PBC over NPBC (HR, 0.31; 95% CI, 0.10-0.92; P = .03). CONCLUSIONS: There is no significant outcome difference between PBC and NPBC in patients with metastatic UC who previously received cisplatin-based chemotherapy for localized disease. However, if over a year has elapsed, return to PBC is associated with superior OS.

Prognostic significance and immune correlates of CD73 expression in renal cell carcinoma.

BACKGROUND: CD73-adenosine signaling in the tumor microenvironment is immunosuppressive and may be associated with aggressive renal cell carcinoma (RCC). We investigated the prognostic significance of CD73 protein expression in RCC leveraging nephrectomy samples. We also performed a complementary analysis using The Cancer Genome Atlas (TCGA) dataset to evaluate the correlation of CD73 (ecto-5'-nucleotidase (NT5E), CD39 (ectonucleoside triphosphate diphosphohydrolase 1 (ENTPD1)) and A2 adenosine receptor (A2AR; ADORA2A) transcript levels with markers of angiogenesis and antitumor immune response. METHODS: Patients with RCC with available archived nephrectomy samples were eligible for inclusion. Tumor CD73 protein expression was assessed by immunohistochemistry and quantified using a combined score (CS: % positive cells×intensity). Samples were categorized as CD73negative (CS=0), CD73low or CD73high (< and ≥median CS, respectively). Multivariable Cox regression analysis compared disease-free survival (DFS) and overall survival (OS) between CD73 expression groups. In the TCGA dataset, samples were categorized as low, intermediate and high NT5E, ENTPD1 and ADORA2A gene expression groups. Gene expression signatures for infiltrating immune cells, angiogenesis, myeloid inflammation, and effector T-cell response were compared between NT5E, ENTPD1 and ADORA2A expression groups. RESULTS: Among the 138 patients eligible for inclusion, 'any' CD73 expression was observed in 30% of primary tumor samples. High CD73 expression was more frequent in patients with M1 RCC (29% vs 12% M0), grade 4 tumors (27% vs 13% grade 3 vs 15% grades 1 and 2), advanced T-stage (≥T3: 22% vs T2: 19% vs T1: 12%) and tumors with sarcomatoid histology (50% vs 12%). In the M0 cohort (n=107), patients with CD73high tumor expression had significantly worse 5-year DFS (42%) and 10-year OS (22%) compared with those in the CD73negative group (DFS: 75%, adjusted HR: 2.7, 95% CI 1.3 to 5.9, p=0.01; OS: 64%, adjusted HR: 2.6, 95% CI 1.2 to 5.8, p=0.02) independent of tumor stage and grade. In the TCGA analysis, high NT5E expression was associated with significantly worse 5-year OS (p=0.008). NT5E and ENTPD1 expression correlated with higher regulatory T cell (Treg) signature, while ADORA2A expression was associated with increased Treg and angiogenesis signatures. CONCLUSIONS: High CD73 expression portends significantly worse survival outcomes independent of stage and grade. Our findings provide compelling support for targeting the immunosuppressive and proangiogenic CD73-adenosine pathway in RCC.

Optimized Management of Nivolumab and Ipilimumab in Advanced Renal Cell Carcinoma: A Response-Based Phase II Study (OMNIVORE).

PURPOSE: In this phase II response-adaptive trial, we investigated the rational application of immune checkpoint blockade in renal cell carcinoma (RCC; ClinicalTrials.gov identifier: NCT03203473). METHODS: We enrolled patients with metastatic RCC with no prior checkpoint inhibitor exposure. All patients received nivolumab alone with subsequent arm allocation based on response. Patients with a confirmed partial response (PR) or complete response (CR) within 6 months discontinued nivolumab and were observed (arm A). Patients with stable disease or progressive disease (PD) after no more than 6 months of nivolumab received two doses of ipilimumab (arm B). The primary endpoints were the proportion of patients with PR/CR at 1 year after nivolumab discontinuation (arm A) and proportion of nivolumab nonresponders who converted to PR/CR after ipilimumab (arm B). RESULTS: Overall, 83 patients initiated treatment, of whom 96% had clear-cell histology, 51% were treatment naïve, and 67% had intermediate/poor-risk disease. Median follow-up was 19.5 months. Within 6 months, induction nivolumab resulted in a confirmed PR in 12% of patients (n = 10). Fourteen patients were not allocated to a study arm (seven because of toxicity, seven because of PD). Twelve patients (14%) were allocated to arm A and discontinued nivolumab, of whom five (42%; 90% CI, 18% to 68%) remained off nivolumab at ≥ 1 year. Of 57 patients (69%) allocated to arm B, two patients converted to a confirmed PR (4%; 90% CI, 1% to 11%), and no CRs were observed. CONCLUSION: In this study, nivolumab followed by two doses of ipilimumab resulted in no CRs and a low PR/CR conversion. The number of patients evaluated for nivolumab discontinuation was too small to assess the value of this approach. Currently, our data do not support a response-adaptive strategy for checkpoint blockade in advanced RCC.

Dual Blockade of c-MET and the Androgen Receptor in Metastatic Castration-resistant Prostate Cancer: A Phase I Study of Concurrent Enzalutamide and Crizotinib.

PURPOSE: Androgen receptor (AR) inhibition can upregulate c-MET expression, which may be a resistance mechanism driving progression of castration-resistant prostate cancer (CRPC). We conducted a phase I trial investigating the safety and pharmacokinetics of a potent c-MET inhibitor, crizotinib, with the AR antagonist, enzalutamide, in CRPC. PATIENTS AND METHODS: Employing a 3+3 dose-escalation design, we tested three dose levels of crizotinib (250 mg daily, 200 mg twice a day, and 250 mg twice a day) with standard-dose enzalutamide (160 mg daily). The primary endpoint was rate of dose-limiting toxicities (DLTs). Tolerability and pharmacokinetics profile were secondary endpoints. RESULTS: Twenty-four patients were enrolled in the dose-escalation (n = 16) and dose-expansion (n = 8) phases. Two DLTs occurred in dose escalation (grade 3 alanine aminotransferase elevation). The MTD of crizotinib was 250 mg twice a day. Most frequent treatment-related adverse events were fatigue (50%), transaminitis (38%), nausea (33%), and vomiting, constipation, and diarrhea (21% each). Grade ≥3 events (25%) included transaminitis (n = 2), fatigue (n = 1), hypertension (n = 1), pulmonary embolism (n = 1), and a cardiac event encompassing QTc prolongation/ventricular arrhythmia/cardiac arrest. Median progression-free survival was 5.5 months (95% confidence interval, 2.8-21.2). Pharmacokinetics analysis at the MTD (n = 12) revealed a mean C max ss of 104 ± 45 ng/mL and AUCτ ss of 1,000 ± 476 ng•h/mL, representing a 74% decrease in crizotinib systemic exposure relative to historical data (C max ss, 315 ng/mL and AUCτ ss, 3,817 ng•h/mL). CONCLUSIONS: Concurrent administration of enzalutamide and crizotinib resulted in a clinically significant 74% decrease in systemic crizotinib exposure. Further investigation of this combination in CRPC is not planned. Our results highlight the importance of evaluating pharmacokinetics interactions when evaluating novel combination strategies in CRPC.

Impact of baseline serum IL-8 on metastatic hormone-sensitive prostate cancer outcomes in the Phase 3 CHAARTED trial (E3805).

BACKGROUND: The immunosuppressive cytokine interleukin- 8 (IL-8), produced by tumor cells and some myeloid cells, promotes inflammation, angiogenesis, and metastasis. In our discovery work, elevated serum IL-8 at androgen deprivation therapy (ADT) initiation portended worse overall survival (OS). Leveraging serum samples from the phase 3 CHAARTED trial of patients treated with ADT +/- docetaxel for metastatic hormone-sensitive prostate cancer (mHSPC), we validated these findings. METHODS: Two hundred and thirty-three patients had serum samples drawn within 28 days of ADT initiation. The samples were assayed using the same Mesoscale Multiplex ELISA platform employed in the discovery cohort. After adjusting for performance status, disease volume, and de novo/metachronous metastases, multivariable Cox proportional hazards models assessed associations between IL-8 as continuous and binary variables on OS and time to castration-resistant prostate cancer (CRPC). The median IL-8 level (9.3 pg/ml) was the a priori binary cutpoint. Fixed-effects meta-analyses of the discovery and validation sets were performed. RESULTS: Higher IL-8 levels were prognostic for shorter OS (continuous: hazard ratio [HR] 2.2, 95% confidence interval [CI]: 1.4-3.6, p = .001; binary >9.3: HR 1.7, 95% CI: 1.2-2.4, p = .007) and time to CRPC (continuous: HR 2.3, 95% CI: 1.6-3.3, p < .001; binary: HR 1.8, 95% CI: 1.3-2.5, p < .001) and independent of docetaxel use, disease burden, and time of metastases. Meta-analysis including the discovery cohort, also showed that binary IL-8 levels >9.3 pg/ml from patients treated with ADT alone was prognostic for poorer OS (HR 1.8, 95% CI: 1.2-2.7, p = .007) and shorter time to CRPC (HR 1.4, 95% CI: 0.99-1.9, p = .057). CONCLUSIONS: In the phase 3 CHAARTED study of men with mHSPC at ADT initiation, elevated IL-8 portended worse survival and shorter time to castration-resistant prostate cancer independent of docetaxel administration, metastatic burden, and metachronous versus de novo metastatic presentation. These findings support targeting IL-8 as a strategy to improve mHSPC outcomes.

Impact of timing of adjuvant chemotherapy following radical cystectomy for bladder cancer on patient survival.

BACKGROUND: Trials of adjuvant chemotherapy following radical cystectomy generally require chemotherapy to start within 90 days postoperatively. However, it is unclear, whether the interval between surgery and start of adjuvant therapy (S-AC-interval) impacts the oncological outcome. METHODS: Using the Retrospective International Study of Invasive/Advanced Cancer of the Urothelium (RISC) data base, we identified patients who underwent radical cystectomy for muscle invasive bladder cancer and subsequent adjuvant chemotherapy. Univariate analysis of patient characteristics, surgical factors and tumor characteristics regarding their impact on S-AC-interval was performed using Kruskal-Wallis testing and Fisher's exact test. Analysis of progression-free (PFS) and overall survival (OS) (follow-up time beginning with the start date of adjuvant chemotherapy) was analyzed in relation to S-AC-interval (continuous and dichotomous with a cut-off at 90 days) using Kaplan-Meier method and COX regression analysis. RESULTS: We identified 238 eligible patients (83.5% male, mean age: 63.4 years, 76.1% T3/T4, 66.4% pN+, 14.7% R+, 70.6% urothelial carcinoma, 71% cisplatin-based adjuvant chemotherapy). The majority of patients (n = 207, 87%) started chemotherapy within 90 days after surgery. Median S-AC-interval was 57 days (interquartile range 32.8). S-AC-interval did not have consistent association with any patient/tumor characteristics or surgery related factors (type of surgery, urinary diversion). Survival analysis using continuous S-AC-interval revealed a trend toward an impact of S-AC-interval on OS (hazard ratio 1.004, 95% confidence ratio 0.9997-1.0084, P = 0.071). With regards to PFS, that impact was shown to be statistically significant (hazard ratio 1.004, 95% confidence ratio 1.0003-1.0075, P = 0.032). In multivariate analysis, however, S-AC-interval was negated by tumor and patient related factors (pathological T-stage, N-stage, ECOG performance status). Accounting for eligibility criteria defined in some clinical trials, we extended our analysis dividing S-AC-interval in ≤90 and >90 days. Although we could confirm the trend toward better outcome in patients with a shorter S-AC interval in dichotomous analysis, neither differences in OS nor in PFS reached statistical significance (P = 0.438 and P = 0.056). CONCLUSIONS: In a large multi-institutional experience, 87% of patients who received adjuvant chemotherapy received it within the guideline recommended window of 90 days. While it was not possible to determine whether this is the optimal cut-off, early start of adjuvant chemotherapy seems to be reasonable. Regarding prognosis, tumor-related pathological factors abrogated the importance of the S-AC-interval in our analysis.

Activity of cabozantinib after immune checkpoint blockade in metastatic clear-cell renal cell carcinoma.

BACKGROUND: Cabozantinib is approved for the first and subsequent line treatment of metastatic clear-cell renal cell carcinoma (ccRCC) based on trials in which most patients were immune checkpoint blockade (ICB) naive. With an expanding role of ICB in earlier lines of therapy, we assessed activity of cabozantinib in patients with metastatic ccRCC after progressing on anti-PD-1/PD-L1-based ICBs. METHODS: We retrospectively analysed the clinical outcomes of 86 patients from 2 academic centres who received cabozantinib after progression on ICB alone, ICB in combination with vascular endothelial growth factor inhibitors (VEGFis) or ICB in combination with other therapies. Overall response rate (ORR, investigator assessed), time to treatment failure (TTF), overall survival (OS) and toxicities leading to dose reductions or cessation were evaluated. RESULTS: Eighty-six patients were included in the analysis; the median age was 63 years (range 33-84) and the median number of prior therapies was 2 (range 1-10). The type of prior ICB therapy was ICBs alone (64%), an ICB in combination with a VEGFi (29%) or ICBs in combination with other therapies (7%). At the time of cabozantinib treatment, 71% of patients were in the International Metastatic RCC Database Consortium good- or intermediate-risk groups. Approximately half of patients (52%) were started on cabozantinib at the full 60 mg daily dose. The ORR was 36% (95% confidence interval [CI] = 26-47%) with no complete response and 43% achieving stable disease; 21% had primary progressive disease. The median TTF was 6.5 months (95% CI = 5.3-8.5.). The median OS was 13.1 months (95% CI = 8.7-NR) with 55% (95% CI = 41-66%) OS rate at 12 months. Most common reasons for dose reductions were fatigue (27%), palmar-plantar erythrodysesthesia (16%) and diarrhoea (10%). CONCLUSIONS: Cabozantinib is active in patients treated with prior ICB-based therapies, with no new safety signals. This study supports the use of cabozantinib after ICB-based therapies.

Conditional immune toxicity rate in patients with metastatic renal and urothelial cancer treated with immune checkpoint inhibitors.

BACKGROUND: Immune checkpoint inhibitors (ICIs) are associated with immune-related adverse events (irAEs). Although the incidence and prevalence of irAEs have been well characterized in the literature, less is known about the cumulative incidence rate of irAEs. We studied the cumulative incidence of irAEs, defined as the probability of irAE occurrence over time and the risk factors for irAE development in metastatic urothelial carcinoma (mUC) and renal cell carcinoma (mRCC) patients treated with ICIs. METHODS: We identified a cohort of patients who received ICIs for mUC and mRCC. irAEs were classified using Common Terminology Criteria for Adverse Event (CTCAE) V.5.0 guidelines. The monthly incidence of irAEs over time was reported after landmark duration of therapy. Cumulative incidence of irAEs was calculated to evaluate the time to the first occurrence of an irAE accounting for the competing risk of death. Prognostic factors for irAE were assessed using the Fine and Gray method. RESULTS: A total of 470 patients were treated with ICIs between July 2013 and October 2018 (mUC: 199 (42.3%); mRCC: 271 (57.7%)). 341 (72.6%) patients received monotherapy, 86 (18.3%) received ICIs in combination with targeted therapies, and 43 (9.2%) received dual ICI therapy. Overall, 186 patients (39.5%) experienced an irAE at any time point. Common irAEs included hypothyroidism (n=42, 22.6%), rush and pruritus (n=36, 19.4%), diarrhea/colitis (n=35, 18.8%), transaminitis (n=32, 17.2%), and pneumonitis (n=14, 7.5%). Monthly incidence rates decreased over time; however, 17 of 109 (15.6%, 95% CI: 9.4% to 23.8%) experienced their first irAE at least 1 year after treatment initiation. No differences in cumulative incidence were observed based on cancer type, agent, or irAE grade. On multivariable analysis, combined ICI therapy with another ICI or with targeted therapy (p<0.001), first-line ICI therapy (p=0.011), and PD-1 inhibitor therapy (p=0.007) were all significantly associated with irAE development. CONCLUSIONS: This study quantitates the incidence of developing irAEs due to ICI conditioned on time elapsed without irAE development. Although the monthly incidence of irAEs decreased over time on therapy, patients can still develop delayed irAEs beyond ICI discontinuation, and thus, continuous vigilant monitoring is warranted.

Safety and efficacy of restarting immune checkpoint inhibitors after clinically significant immune-related adverse events in metastatic renal cell carcinoma.

BACKGROUND: Immune checkpoint inhibitors (ICI) induce a range of immune-related adverse events (irAEs) with various degrees of severity. While clinical experience with ICI retreatment following clinically significant irAEs is growing, the safety and efficacy are not yet well characterized. METHODS: This multicenter retrospective study identified patients with metastatic renal cell carcinoma treated with ICI who had >1 week therapy interruption for irAEs. Patients were classified into retreatment and discontinuation cohorts based on whether or not they resumed an ICI. Toxicity and clinical outcomes were assessed descriptively. RESULTS: Of 499 patients treated with ICIs, 80 developed irAEs warranting treatment interruption; 36 (45%) of whom were restarted on an ICI and 44 (55%) who permanently discontinued. Median time to initial irAE was similar between the retreatment and discontinuation cohorts (2.8 vs 2.7 months, p=0.59). The type and grade of irAEs were balanced across the cohorts; however, fewer retreatment patients required corticosteroids (55.6% vs 84.1%, p=0.007) and hospitalizations (33.3% vs 65.9%, p=0.007) for irAE management compared with discontinuation patients. Median treatment holiday before reinitiation was 0.9 months (0.2-31.6). After retreatment, 50% (n=18/36) experienced subsequent irAEs (12 new, 6 recurrent) with 7 (19%) grade 3 events and 13 drug interruptions. Median time to irAE recurrence after retreatment was 2.8 months (range: 0.3-13.8). Retreatment resulted in 6 (23.1%) additional responses in 26 patients whose disease had not previously responded. From first ICI initiation, median time to next therapy was 14.2 months (95% CI 8.2 to 18.9) and 9.0 months (5.3 to 25.8), and 2-year overall survival was 76% (95%CI 55% to 88%) and 66% (48% to 79%) in the retreatment and discontinuation groups, respectively. CONCLUSIONS: Despite a considerable rate of irAE recurrence with retreatment after a prior clinically significant irAE, most irAEs were low grade and controllable. Prospective studies are warranted to confirm that retreatment enhances survival outcomes that justify the safety risks.

Effect of Antibiotic Use on Outcomes with Systemic Therapies in Metastatic Renal Cell Carcinoma.

BACKGROUND: Antibiotic use alters commensal gut microbiota, which is a key regulator of immune homeostasis. OBJECTIVE: To investigate the impact of antibiotic use on clinical outcomes in metastatic renal cell carcinoma (mRCC) patients treated with systemic agents. DESIGN, SETTING, AND PARTICIPANTS: We analyzed two cohorts: an institutional cohort (n=146) receiving programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1)-based immune checkpoint inhibitors (ICIs) and a trial-database cohort (n=4144) receiving interferon-α (n=510), mammalian target of rapamycin (mTOR) inhibitors (n=660), and vascular endothelial growth factor targeted therapies (VEGF-TT; n=2974) on phase II/III clinical trials. OUTCOMES MEASUREMENTS AND STATISTICAL ANALYSIS: The association of antibiotic use (defined as use from 8 wk before to 4 wk after the initiation of anticancer therapy) with progression-free survival (PFS) and overall survival (OS) was evaluated using Cox regression, adjusted for known prognostic factors including International Metastatic RCC Database Consortium risk factors. RESULTS AND LIMITATIONS: Most patients were male, had clear cell histology, and were at an intermediate risk. Overall, in the institutional cohort, objective response rate (ORR) was 30%, PFS was 7.2 mo, and 1-yr OS was 77%. Antibiotic users (n=31, 21%) had a lower ORR (12.9% vs 34.8%, p=0.026) and shorter PFS (adjusted hazard ratio [HR]=1.96, 95% confidence interval [CI] 1.20-3.20, p=0.007) than antibiotic nonusers. In the trial-database cohort, antibiotic use (n=709, 17%) adversely impacted OS in patients treated with interferon (HR=1.62, 95% CI 1.13-2.31, p=0.008) or with VEGF-TT and prior cytokines (HR=1.65, 95% CI 1.04-2.62, p=0.033), but not patients treated with mTOR inhibitors or VEGF-TT without prior cytokines. Limitations include retrospective design, and limited details regarding concomitant medications and antibiotic indication/duration. CONCLUSIONS: Antibiotic use appears to reduce the efficacy of immunotherapy-based regimens in mRCC. The modulation of gut microbiota may play an important role in optimizing outcomes of patients treated with ICIs. PATIENT SUMMARY: We evaluated metastatic renal cell carcinoma patients and found that those who were treated with immunotherapy had worse outcomes if they also received antibiotics at the start of treatment. This study highlights the importance of judicious antibiotic use.

Incidence, Patterns, and Outcomes with Adjuvant Chemotherapy for Residual Disease After Neoadjuvant Chemotherapy in Muscle-invasive Urinary Tract Cancers.

BACKGROUND: Patients with residual muscle-invasive urinary tract cancer after neoadjuvant chemotherapy (NAC) have a high risk of recurrence. OBJECTIVE: To retrospectively evaluate whether additional adjuvant chemotherapy (AC) improves outcomes compared with surveillance in patients with significant residual disease despite NAC. DESIGN, SETTING, AND PARTICIPANTS: We identified 474 patients who received NAC from the Retrospective International Study of Cancers of the Urothelium database, of whom 129 had adverse residual disease (≥ypT3 and/or ypN+). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Time to relapse (TTR) was the primary endpoint assessed starting from 2mo after surgery to minimize immortal time bias. Secondary endpoints included overall survival (OS), incidence of AC use, and chemotherapy patterns. Kaplan-Meier and Cox regression models estimated TTR, OS, and associations with AC, adjusting for the type of NAC, age, and pathological stage in multivariable analyses. RESULTS AND LIMITATIONS: A total of 106 patients underwent surveillance, while 23 received AC. Gemcitabine-cisplatin was the most frequent regimen employed in both settings (30.4%), and the majority (82.6%) of the patients switched to a different regimen. Median follow-up was 30mo. Over 50% of patients developed a recurrence. Median TTR was 16mo (range: <1-108mo). Longer median TTR was observed with AC compared with surveillance (18 vs 10mo, p=0.06). Risk of relapse significantly decreased with AC when adjusted in multivariable analyses (p=0.01). The subgroup analyses of ypT4b/ypN+ patients (AC: 19; surveillance: 50) who received AC had significantly greater median TTR (20 vs 9mo; hazard ratio 0.43; 95% confidence interval: 0.21-0.89). No difference in OS was found. Limitations include the retrospective design. CONCLUSIONS: The utilization of AC after NAC in patients with high-risk residual disease is not frequent in clinical practice but might reduce the risk of recurrence. Further investigation is needed in this high-risk population to identify optimal therapy and to improve clinical outcomes such as the ongoing adjuvant immunotherapy trials. PATIENT SUMMARY: We found that administering additional chemotherapy in patients who had significant residual disease despite preoperative chemotherapy is not frequent in clinical practice. While it might reduce the risk of recurrence, it did not clearly increase overall survival. We encourage participation in the ongoing immunotherapy trials to see whether we can improve outcomes using a different type of therapy that stimulates the immune system.

A model combining clinical and genomic factors to predict response to PD-1/PD-L1 blockade in advanced urothelial carcinoma.

BACKGROUND: In metastatic urothelial carcinoma (mUC), predictive biomarkers that correlate with response to immune checkpoint inhibitors (ICIs) are lacking. Here, we interrogated genomic and clinical features associated with response to ICIs in mUC. METHODS: Sixty two mUC patients treated with ICI who had targeted tumour sequencing were studied. We examined associations between candidate biomarkers and clinical benefit (CB, any objective reduction in tumour size) versus no clinical benefit (NCB, no change or objective increase in tumour size). Both univariable and multivariable analyses for associations were conducted. A comparator cohort of 39 mUC patients treated with taxanes was analysed by using the same methodology. RESULTS: Nine clinical and seven genomic factors correlated with clinical outcomes in univariable analysis in the ICI cohort. Among the 16 factors, neutrophil-to-lymphocyte ratio (NLR) ≥5 (OR = 0.12, 95% CI, 0.01-1.15), visceral metastasis (OR = 0.05, 95% CI, 0.01-0.43) and single-nucleotide variant (SNV) count < 10 (OR = 0.04, 95% CI, 0.006-0.27) were identified as independent predictors of NCB to ICI in multivariable analysis (c-statistic = 0.90). None of the 16 variables were associated with clinical benefit in the taxane cohort. CONCLUSIONS: This three-factor model includes genomic (SNV count >9) and clinical (NLR <5, lack of visceral metastasis) variables predictive for benefit to ICI but not taxane therapy for mUC. External validation of these hypothesis-generating results is warranted to enable use in routine clinical care.