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.

Abstract 1137: Determination of a recommended Phase 2 dose (RP2D) for SRF388, a first-in-class IL-27-blocking antibody, in patients with advanced solid tumors

SRF388 is a first-in-class, anti-IL-27 antibody developed to enhance immune responses within the tumor microenvironment. Preclinical studies have demonstrated that IL-27 pathway blockade can inhibit tumor growth in mouse models of liver cancer and lung cancer metastases. There is also evidence that IL-27 pathway inhibition is accompanied by activation of the innate and adaptive arms of the immune system. An ongoing Phase I trial has shown good tolerability at all dose levels tested and preliminary monotherapy antitumor activity with SRF388 (NCT04374877). Here, we describe the preclinical and clinical data used to select a RP2D and characterize cytokine and chemokine changes observed in patients after treatment with SRF388. To guide selection of the RP2D, the relationship between maximal effective dose (MaxED), pharmacokinetics (PK), and whole blood inhibition of IL-27-mediated phosphorylation of STAT1 by SRF388 was evaluated in a mouse model of liver cancer. The concentration of SRF388 associated with optimal antitumor activity was ~20-fold above the concentration needed for complete inhibition (> 90%) of whole blood phosphorylated STAT1 (pSTAT1). These PK and activity relationships were also defined in patients during the dose-escalation phase of the trial and integrated with safety and efficacy data to select a monotherapy RP2D. In patients, PK were linear, no dose-limiting toxicities were reported, complete pSTAT1 inhibition was achieved throughout the first cycle at 0.3 mg/kg, and 1 patient experienced a confirmed partial response per RECIST version 1.1 at a dose of 10 mg/kg. In the MaxED mouse model, the area under the concentration versus time curve (AUC) associated with significant antitumor activity was 1720 day*μg/mL. In patients, the corresponding target AUC was achieved clinically at 10 mg/kg after a single dose of SRF388. Changes in the concentration of several serum cytokines and chemokines were observed after SRF388 treatment including an increase in IL-27, a phenomenon described for other anti-cytokine antibodies due to altered clearance of the cytokine-antibody complex. Changes in a subset of other serum cytokines/chemokines correlated with a reduction in target lesion size. Taken together, these data support the selection of a monotherapy RP2D of 10 mg/kg intravenously every 4 weeks for SRF388. These data highlight how complementary strategies utilizing preclinical and clinical biomarker evaluations can be employed to establish a monotherapy RP2D and assess biological activity of a first-in-class anti-cytokine antibody, SRF388, for patients with cancer.

Citation Format: Jonathan A. Hill, Kerry F. White, Matthew Rausch, Jou-Ku Chung, Amita Patnaik, Aung Naing, Daniel Morgensztern, Charlene M. Mantia, Nizar M. Tannir, Lon S. Smith, Beth Bowers, Alex Alika, Lauren C. Harshman, Benjamin H. Lee. Determination of a recommended Phase 2 dose (RP2D) for SRF388, a first-in-class IL-27-blocking antibody, in patients with advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1137.

First-in-human study of SRF388, a first-in-class IL-27 targeting antibody, as monotherapy and in combination with pembrolizumab in patients with advanced solid tumors

2501

Background: The immunoregulatory cytokine IL-27 upregulates inhibitory immune checkpoint receptors (eg, PD-L1, TIGIT) and downregulates proinflammatory cytokines (eg, IFNγ, TNFα). SRF388 is a fully human IgG1 blocking antibody to IL-27 with potential to promote immune activation in the tumor microenvironment. A phase 1 study was conducted to establish the preliminary safety of SRF388 and to identify recommended phase 2 doses (RP2D) suitable for monotherapy and combination expansions (NCT04374877). Methods: The dose-escalation study (accelerated single patient followed by standard 3+3) enrolled patients (pts) with advanced treatment-refractory solid tumors. Upon RP2D selection, monotherapy and combination expansions opened for treatment-refractory clear cell renal cell cancer (ccRCC), hepatocellular cancer (HCC), and non-small cell lung cancer. SRF388 was administered IV every 4 weeks (wks) as monotherapy and every 3 wks with pembrolizumab. Tumor response was assessed by RECIST1.1. Results: The monotherapy dose-escalation enrolled 29 pts with doses ranging from 0.003 to 20 mg/kg. Median age was 64 years. Most pts were female (62%) with ECOG PS of 1 (72%). Approximately 80% had prior PD-(L)1 blockade, and 48% had ≥4 prior therapies. Treatment-related adverse events (TRAEs) occurred in 21%, and all were low grade. Fatigue was the only TRAE reported in ≥10% (n = 3). No dose-limiting toxicities (DLTs) or Grade ≥3 TRAEs were observed. Median time on study was 9 wks (range 0–59). One patient with highly treatment-refractory NSCLC experienced a confirmed partial response (PR) at 8 wks that was durable for 20 wks. Nine pts (31%) experienced disease stabilization at 8 wks, with 6 of 9 exhibiting durable disease control at 6 months. Of the 7 pts with ccRCC in the dose-escalation portion of the trial, 3 (43%) experienced durable disease control for ≥20 wks (range: 20-32). With doses up to 20 mg/kg, SRF388 PK remain linear with an estimated T1/2 of 10-12 days. PK characteristics and safety profile support dosing every 3 or 4 wks. Based on safety, tolerability, PK, peripheral pSTAT1 inhibition, and preliminary efficacy, 10 mg/kg was selected as the RP2D. Both the pembrolizumab safety cohort (n = 10) and Stage 1 of the ccRCC monotherapy expansion (n = 17) have fully enrolled. Of the 10 evaluable pts with ccRCC, 1 confirmed monotherapy PR has been reported, enabling Stage 2 initiation. Changes in several serum cytokines and chemokines were observed after SRF388 administration, including expected increase in circulating IL-27 levels. Conclusions: Results of IL-27 pathway blockade with a first-in-class therapeutic demonstrates that SRF388 has good tolerability with encouraging preliminary antitumor activity as a monotherapy. Updated data, including safety and clinical outcomes as well as correlative biomarker analyses, will be presented. Clinical trial information: NCT04374877.

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.

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.

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 CD73_negative (CS=0), CD73_low or CD73_high (< 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 CD73_high tumor expression had significantly worse 5-year DFS (42%) and 10-year OS (22%) compared with those in the CD73_negative 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.

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.

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 efficacy of immune checkpoint inhibitors in advanced urological cancers with pre-existing autoimmune disorders: a retrospective international multicenter study

BACKGROUND

There is limited experience regarding the safety and efficacy of checkpoint inhibitors (CPI) in patients with autoimmune disorders (AD) and advanced urological cancers as they are generally excluded from clinical trials due to risk of exacerbations.

METHODS

This multicenter retrospective cohort analysis of patients with advanced renal cell cancer (RCC) and urothelial cancer (UC) with pre-existing AD treated with CPI catalogued the incidence of AD exacerbations, new immune-related adverse events (irAEs) and clinical outcomes. Competing risk models estimated cumulative incidences of exacerbations and new irAEs at 3 and 6 months.

RESULTS

Of 106 patients with AD (58 RCC, 48 UC) from 10 centers, 35 (33%) had grade 1/2 clinically active AD of whom 10 (9%) required corticosteroids or immunomodulators at baseline. Exacerbations of pre-existing AD occurred in 38 (36%) patients with 17 (45%) requiring corticosteroids and 6 (16%) discontinuing CPI. New onset irAEs occurred in 40 (38%) patients with 22 (55%) requiring corticosteroids and 8 (20%) discontinuing CPI. Grade 3/4 events occurred in 6 (16%) of exacerbations and 13 (33%) of new irAEs. No treatment-related deaths occurred. Median follow-up was 15 months. For RCC, objective response rate (ORR) was 31% (95% CI 20% to 45%), median time to treatment failure (TTF) was 7 months (95% CI 4 to 10) and 12-month overall survival (OS) was 78% (95% CI 63% to 87%). For UC, ORR was 40% (95% CI 26% to 55%), median TTF was 5.0 months (95% CI 2.3 to 9.0) and 12-month OS was 63% (95% CI 47% to 76%).

CONCLUSIONS

Patients with RCC and UC with well-controlled AD can benefit from CPI with manageable toxicities that are consistent with what is expected of a non-AD population. Prospective study is warranted to comprehensively evaluate the benefits and safety of CPI in patients with AD.

Results of a phase 1 study of SRF388, a first-in-human, first-in-class, high-affinity anti-IL-27 antibody in advanced solid tumors

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Background: IL-27 is an immunosuppressive cytokine, consisting of two subunits p28 and EBI3, that upregulates immune checkpoint receptors (eg, PD-L1, TIGIT) and downregulates proinflammatory cytokines such as IFNγ, TNFα, and IL-17. SRF388 is a first-in-class, fully human IgG1 antibody to IL-27 that blocks the interaction between IL-27 and its receptor, thereby promoting immune activation in the tumor microenvironment. The IL-27 pathway is activated in hepatocellular carcinoma (HCC) and renal cell carcinoma (RCC), and high circulating levels of EBI3 are associated with inferior outcomes in both. Circulating EBI3 levels may serve as a predictive biomarker of SRF388 activity. Methods: Patients with advanced solid tumors refractory to standard therapy were enrolled in a phase 1 dose-escalation study (accelerated single patient followed by standard 3+3) to establish the preliminary safety of SRF388 as a monotherapy and to identify a dose suitable for expansion (NCT04374877). SRF388 was administered intravenously every 4 weeks. Tumor response was assessed by RECIST v1.1. SRF388 pharmacokinetic (PK) and pharmacodynamic (PD) [phospho-STAT (pSTAT) inhibition] analyses were performed. Results: As of January 26, 2021, 12 patients have received SRF388 at doses ranging from 0.003 to 10 mg/kg with 2 patients undergoing intra-patient dose escalation. Median age was 68 years, 67% were female, and ECOG PS was 0/1 (42%/58%). Median number of prior therapies was 2 (range 1–9), and 75% were anti-PD-(L)1 experienced (n = 9). The only treatment-related adverse events observed across dose levels were low-grade fatigue (n = 1, 8%), nausea (n = 1, 8%) and excess salivation (n = 1, 8%). No dose-limiting toxicities (DLTs) or ≥ Grade 3 related toxicity have occurred. Mean time on study is 12.5 weeks (range 4–40). One patient with RCC who received prior anti-PD-1 has prolonged stable disease for > 9 months. SRF388 PK are linear with estimated T1/2 ranging from 6–19 days. There is evidence of accumulation and no anti-drug antibody development to date. Maximal inhibition of the IL-27 signaling pathway as measured by > 90% pSTAT inhibition in whole blood was achieved starting at 0.3 mg/kg. Given combined evidence of near-complete pathway inhibition and preclinical human equivalent dose modeling projecting biologically active doses, additional slots were opened for RCC and HCC starting at 1 mg/kg. Conclusions: Preliminary results of IL-27 pathway blockade with a first-in-class therapeutic demonstrates that SRF388 is well tolerated at doses that achieve maximal inhibition of downstream pSTAT signaling through the dosing period. Expansions are planned in HCC and RCC. Updated data including the recommended phase 2 dose, clinical outcomes, PK/PD and correlative analyses will be presented. Clinical trial information: NCT04374877.

PROSPER: Phase III RandOmized Study Comparing PERioperative nivolumab versus observation in patients with renal cell carcinoma (RCC) undergoing nephrectomy (ECOG-ACRIN EA8143)

TPS4596

Background: There is no standard adjuvant systemic therapy that increases overall survival (OS) over surgery alone for non-metastatic RCC. Anti-PD-1 nivolumab (nivo) improves OS in metastatic RCC and is well tolerated. In mouse models, priming the immune system prior to surgery with anti-PD-1 results in superior OS compared to adjuvant dosing. Remarkable pathologic responses have been seen with neoadjuvant PD-1 in multiple ph 2 studies in bladder, lung and breast cancers. Phase 2 neoadjuvant RCC trials of nivo show preliminary feasibility and safety with no surgical delays. PROSPER RCC seeks to improve clinical outcomes by priming the immune system with neoadjuvant nivo prior to nephrectomy followed by continued immune system engagement with adjuvant blockade in patients (pts) with high risk RCC compared to standard of care surgery alone. Methods: This global, unblinded, phase 3 National Clinical Trials Network study is accruing pts with clinical stage ≥T2 or TanyN+ RCC of any histology planned for radical or partial nephrectomy. Select oligometastatic disease is permitted if the pt can be rendered ‘no evidence of disease’ within 12 weeks of nephrectomy (≤3 metastases; no brain, bone or liver). In the investigational arm, nivo is administered 480mg IV q4 weeks with 1 dose prior to surgery followed by 9 adjuvant doses. The control arm is nephrectomy followed by standard of care surveillance. There is no placebo. Baseline tumor biopsy is required only in the nivo arm but encouraged in both. Randomized pts are stratified by clinical T stage, node positivity, and M stage. 805 pts provide 84.2% power to detect a 14.4% absolute benefit in recurrence-free survival at 5 years assuming the ASSURE historical control of ̃56% to 70% (HR = 0.70). The study is powered to evaluate a significant increase in OS (HR 0.67). Critical perioperative therapy considerations such as safety, feasibility, and quality of life metrics are integrated. PROSPER RCC embeds a wealth of translational studies to examine the contribution of the baseline immune milieu and neoadjuvant priming with anti-PD-1 on clinical outcomes. As of February 10, 2021, 704 patients have been enrolled (N = 805). Clinical trial information: NCT03055013.

Activity and safety of cabozantinib (cabo) in brain metastases (BM) from metastatic renal cell carcinoma (mRCC): An international multicenter study

310

Background: Cabo shows robust clinical activity in mRCC. Patients (pts) with BM have been underrepresented in clinical trials and effective systemic therapy is lacking. We retrospectively characterized the clinical activity and toxicity of cabo in pts with BM from RCC. Methods: Consecutive medical records from mRCC pts with BM treated with cabo monotherapy across 15 institutions were reviewed. Pts were grouped by radiologic presence (cohort 1) or absence (cohort 2) of progressing intracranial metastases. Brain-directed local therapy was allowed but radiological confirmation of intracranial progression at cabo start was required in cohort 1. Radiological response rate was investigator-assessed by modified RECIST 1.1 for intracranial and RECIST 1.1 for extracranial responses. Time to treatment failure (TTF) and overall survival (OS) were estimated by Kaplan-Meier. Results: We identified 69 pts with BM from RCC, 25 (36%) in cohort 1 and 44 (64%) in cohort 2. Majority were IMDC intermediate/poor (87%) and received cabo as ≥2nd line (75%). Median time from mRCC diagnosis to BM was 19.1 months (mos) (IQR 4.4-39.5). Overall, median number of BM was 3 (range 1-27) and median size of largest lesion was 1.2 cm (range 0.2-6.6) with frontal (62%) and parietal (48%) as the most frequent localizations. Prior brain directed therapy was used in 65% and 93% of pts in cohort 1 and 2 respectively. Median follow-up after cabo initiation was 11 mos (range 4-72). Twenty three percent of pts remained on therapy while 52% discontinued for progression and 9% for toxicity. Intracranial response rate was 61% (95%CI 39%-80%), with 3 complete responses, for cohort 1 and 57% (95%CI 41%-72%) for cohort 2. Only 10% (n = 7) had intracranial progression as best response. For cohort 1, extracranial response was 52% (95%CI 31%-72%), median TTF was 9.9 mos (95%CI 5.9-14.0) and OS was 14.7 mos (95%CI 7.7-23.0). For cohort 2, extracranial response was 41% (95%CI 26%-57%), TTF was 9.0 mos (95%CI 4.6-11.4) and OS was 14.1 mos (95%CI 11.0-22.0). Most common adverse events were fatigue (77%) and diarrhea (46%). Eight pts received concomitant brain-directed treatment during cabo therapy without neurological toxicities. Conclusions: Cabo shows significant intracranial activity and acceptable safety profile in pts with BM from RCC. [Table: see text]

Efficacy of platinum re-challenge in metastatic urothelial carcinoma (mUC): A retrospective comparison of chemotherapy regimens

459

Background: First-line platinum-based combination chemotherapy (fPBC) is standard of care for fit patients with mUC. Further lines of therapy include immuno-oncology agents, erdafitinib, and enfortumab vedotin, but patients ineligible for these therapies or who subsequently progress may be considered for further chemotherapy. As the choice of chemotherapy regimen is unclear for these patients, we compared the efficacy of subsequent platinum-based chemotherapy (sPBC) and subsequent non-platinum-based chemotherapy (sNPBC) in patients with mUC. Methods: Data was analyzed from the Retrospective International Study of Cancers of the Urothelium (RISC), comprising patients from 28 international centers treated 2005-2012. Inclusion criteria were diagnosis of mUC, receipt of fPBC for mUC, and receipt of ≥2 cycles of subsequent chemotherapy. Patients who had received prior platinum-based chemotherapy in the non-metastatic setting were excluded. A multivariate Cox proportional hazards model was used to compare overall survival (OS), while χ2 and student’s t-test were used for univariate analyses. A two-sided p value of <0.05 was considered statistically significant. Results: Of 296 patients, 135 received sPBC and 161 received sNPBC. Common sNPBC regimens contained gemcitabine, taxanes, or pemetrexed. Baseline characteristics were similar, including Charlson Comorbidity Index (CCI) and performance status (PS), except more patients in the sPBC group had achieved investigator-designated stable disease or response (SD/R) with fPBC (75.4% vs. 63.3%, p = 0.031) and had higher hemoglobin values (median 11.9 vs. 11.1 g/dL, p = 0.004). OS was superior for patients receiving sPBC (median 7.9 months) compared to sNPBC (median 5.5 months) after adjusting for CCI, PS, presence of liver metastases, time since fPBC, and number of fPBC cycles received (HR 0.72, 95% CI 0.53-0.98, p = 0.035). 70 patients (57.4%) achieved SD/R with sPBC and 65 (44.8%) with sNPBC (p = 0.041). Achieving SD/R with subsequent chemotherapy was not associated with number of fPBC cycles received, but for sPBC was associated with longer time since fPBC (median 5.9 vs. 2.9 months, p = 0.033); the same was not true for sNPBC (median 2.2 vs. 2.6 months, p = 0.057). Achieving SD/R with fPBC was associated with greater likelihood of SD/R with sPBC (63.2% vs. 29.6%, p = 0.002), but not sNPBC (50.5% vs. 38.8%, p = 0.185). Liver metastases were negatively associated with likelihood of SD/R with sPBC (43.8% vs. 63.6%, p = 0.038), but not sNPBC (36.2% vs 49.0%, p = 0.147). Conclusions: After treatment with fPBC for mUC, patients able to receive sPBC had better OS compared to those who received sNPBC in a multivariate model. Patients were also more likely to achieve SD/R with sPBC; factors associated with achieving SD/R with sPBC but not sNPBC included longer interim since fPBC, achieving SD/R to fPBC, and absence of liver metastases.

Biomarker-based phase II study of sapanisertib (TAK-228), an mTORC1/2 inhibitor in patients with refractory metastatic renal cell carcinoma (mRCC)

306

Background: Approved rapalogs inhibit mTORC1 and have limited activity in mRCC, possibly due to compensatory feedback loops. Sapanisertib addresses the incomplete inhibition of the mTOR pathway through targeting of both mTORC1 and mTORC2 with antitumour activity demonstrated in patients with mRCC. In this multicenter, single arm phase II trial, we evaluated the efficacy of sapanisertib in patients with mRCC progressing on standard therapies (NCT03097328). Methods: Eligible mRCC patients had an ECOG performance status of 0-2 and had progressed on standard therapies. Prior therapy with rapalogs (everolimus, temsirolimus) and variant RCC histologies were permitted. Patients had a baseline biopsy and received treatment with sapanisertib 30 mg by mouth weekly until unacceptable toxicity or disease progression. The primary endpoint was overall response rate (ORR) by RECIST 1.1. Tissue biomarkers of mTOR pathway activation were explored. Results: We enrolled 38 mRCC patients (clear cell = 28; variant histology = 10) between August 2017 and November 2019. The majority had intermediate (76%) or poor risk (11%) by IMDC criteria. Twenty (53%) had received ≥ 3 lines of therapy; 13 (34%) patients received prior rapalogs. Median follow-up was 10.4 months (range 1-27.4) and median duration of therapy was 1.6 (range 0.3-13.8) months. ORR by central review was 2 of 38 (5.3% 90%CI: 1%-15.6%). 31.6% of all patients and 30.7% of those with prior rapalog exposure had some tumor shrinkage during course of treatment. Median progression free survival (PFS) was 2.5 months (95% CI 1.8,3.7). Twelve patients (32%) developed treatment-related grade 3 adverse events (AEs) with no grade 4 or 5 toxicity reported; 6 patients (16%) required dose reduction and 4 (11%) discontinued therapy for AEs. Oncopanel tumor sequencing identified alterations in the mTOR pathway in 6 of 29 patients ( MTOR n = 2, PTEN n = 3, TSC1 n = 1.) Reduced PTEN expression by immunohistochemistry was seen in 7 of 19 patients. There was no association between mTOR pathway mutations or PTEN loss and response to sapanisertib. Conclusions: In this study we demonstrate minimal activity of sapanisertib in patients with treatment refractory mRCC with no clear benefit among patients with mTOR/PTEN pathway alterations. Additional treatment strategies are needed for patients with refractory mRCC.

Randomized phase II study evaluating the addition of pembrolizumab to radium-223 in metastatic castration-resistant prostate cancer

98

Background: Treatment (tx) options for patients (pts) with metastatic castration-resistant prostate cancer (mCRPC) to bone are limited. Radium-223 (R223) has demonstrated overall survival (OS) benefit, but objective clinical responses to R223 or the anti-PD1 checkpoint inhibitor (CPI) pembrolizumab (pem) are infrequent. As R223 may increase immunogenicity of mCRPC to bone and increase activity of CPI, we undertook a Phase 2 study to assess safety of the combination and differences in immune cell infiltrate in bone biopsies (bx) and preliminary clinical activity of R223 + pem vs. R223 alone. Methods: Eligibility required mCRPC to bone with no visceral metastases (mets) or lymph nodes > 2 cm, ECOG PS 0 or 1, Hgb ≥ 9 g/dL, and no prior R223 or CPI. Pts underwent bone bx at screening and at 8 wks. Pts were stratified by alkaline phosphatase ≥220 vs. < 220 U/L and high vs. low volume bony mets (CHAARTED criteria) and randomized 2:1 to receive R223 55 kBq/kg q4wks + pem 200 mg q3wks (Arm A) or R223 55 kBq/kg q4wks alone (Arm B). If restaging after 3 doses R223 showed at least stable disease, pts in Arm A continued pem alone until progressive disease (PD). Upon PD, R223 was resumed if no new visceral mets. Pts continued tx until clinical/radiologic PD, unacceptable toxicity or completion of 6 R223 doses. The primary endpoint was difference in CD4+ and CD8+ T-cell infiltrate in 8 wk vs. baseline bx; secondary endpoints were safety/tolerability, radiographic progression-free survival (rPFS) and OS. Exploratory endpoints included PSA response and rate of symptomatic skeletal events (SSEs). Results: Of 45 pts enrolled, 42 received study tx (29 Arm A, 13 Arm B) and were eligible for analysis. 21 pts in Arm A and 5 in Arm B had evaluable paired bone bx. Median fold-change of proportion of CD4+ T-cells/total cell count from baseline to 8 wks was 0.90 (range 0.0-26.6) in Arm A and 0.40 (0.0-13.0) in Arm B (P = 0.87); for CD8+ cells, median 0.67 (0.0-40.4) in Arm A and 0.40 (0.1-28.8) in Arm B (P = 0.77). Grade 3 treatment-related non-hematologic adverse events (AEs) occurred in 3 pts (10%) in Arm A (pneumonitis, diarrhea, AST increased); none in Arm B. Median rPFS was 6.7 mo (95% CI 2.7-11.0 mo) in Arm A and 5.7 mo (2.6-NR) in Arm B. Median OS was 16.9 mo (12.7-NR) in Arm A and 16.0 mo (9.0-NR) in Arm B. 3 pts (10%) in Arm A and 0 in Arm B had PSA reduction of ≥ 50%. SSE rate was 38% in Arm A and 54% in Arm B, with pathologic fractures in 0% of pts in Arm A and 23% in Arm B. Conclusions: In the 62% of treated pts with evaluable paired bx at baseline and after 8 wks, there was no evidence of increased CD4+ or CD8+ T-cell infiltration with R223 + pem. Additional biomarker analyses will be presented. This study revealed that R233 + pem did not result in unexpected AEs, but did not lead to prolonged rPFS or OS compared to R223 alone to support this two-drug combination in a biomarker-unselected population in this setting. Clinical trial information: NCT03093428.

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.

Sarcomatoid and rhabdoid tumours are highly aggressive forms of renal cell carcinoma that are also responsive to immunotherapy. In this study, the authors perform a comprehensive molecular characterization of these tumours discovering an enrichment of specific alterations and an inflamed phenotype.

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.

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.

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 AUC_τ ^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 AUC_τ ^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 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.

Safety and overall survival (OS) in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC) treated with radium-223 (Ra-223) plus subsequent taxane therapy

5542

Background: Ra-223, a targeted alpha therapy, showed a survival benefit and favorable safety profile over 3 years’ (yrs) follow-up in mCRPC pts (ALSYMPCA trial). REASSURE (NCT02141438) is a global, prospective, single-arm, observational study of long-term Ra-223 safety in routine clinical practice in mCRPC pts (planned 7-yr follow-up). Methods: This analysis, based on the second prespecified interim analysis (data cutoff 3-20-2019) of REASSURE (N = 1465), evaluated safety/OS in the pt subset that was chemotherapy-naïve at Ra-223 administration but received subsequent taxane therapy any time after Ra-223 completion. Results: 182 pts received taxane therapy after Ra-223. Most (58%) had unresected primary tumors, 69% had ≥6 metastases, 99% received prior systemic anticancer therapy (Table). 143 (79%) completed 5 or 6 Ra-223 injections. Subsequent anticancer therapies included docetaxel (95%), enzalutamide (25%), cabazitaxel (24%), abiraterone (12%), lutetium-177-prostate-specific membrane antigen (4%), and sipuleucel-T (1%). During/up to 30 days after taxane therapy, 15 pts (8%) had grade 3/4 hematologic adverse events: anemia (erythropenia) (n = 11, 6%), neutropenia (n = 3, 2%), and thrombocytopenia (n = 2, 1%). Median OS was 24.3 (95% CI: 20.9–27.5) months from Ra-223 initiation and 11.8 (95% CI: 10.6–14.1) months from subsequent taxane initiation. Conclusions: In this cohort where Ra-223 was integrated prior to taxane therapy, most pts received multiple subsequent anticancer therapies. It appears that sequencing of multiple treatment modalities with different mechanisms of action may contribute to improved OS. Taxane therapy in routine clinical practice in pts previously treated with Ra-223 had acceptable hematologic safety/tolerability profiles. Clinical trial information: NCT02141438 . [Table: see text]

Treatment of metastatic recurrence of urothelial carcinoma after previous cisplatin-based chemotherapy: A retrospective comparison of different chemotherapy regimens

e17005

Background: The optimal choice of first-line chemotherapy for urothelial carcinoma (UC) patients who recur after previous cisplatin-based chemotherapy for locally-advanced disease is unclear. Our objective is to compare the efficacy of platinum (PBC) versus non-platinum (NPBC) based first-line chemotherapy regimens for such patients after metastatic recurrence. Methods: Data was collected from the Retrospective International Study of Cancers of the Urothelial Tract (RISC), a database consisting of patients with muscle-invasive or advanced UC from 28 centers between 2005 and 2012. Patient inclusion criteria included: 1) UC with no initial metastases (cT2-4, cN0-N3, and cM0), 3) receipt of cisplatin in the locally advanced setting, and 4) receipt of chemotherapy in the first-line metastatic setting. Overall survival (OS) was the primary endpoint. Secondary endpoints included progression-free survival (PFS) and response to chemotherapy. Kaplan-Meier and Cox regression models estimated OS, PFS, and response, adjusting for age, gender, Eastern Cooperative Oncology Group (ECOG-PS), Charlson comorbidity index (CCI), surgery, T and N stage, albumin, creatinine clearance, number of initial cisplatin cycles, and time from last chemotherapy. Results: 152 patients with metastatic UC (88 PBC and 64 NPBC) were analyzed. Twelve (7.9%) patients received local definitive radiation and 7 of these 12 also underwent cystectomy. The most common NPBC regimens included taxanes, gemcitabine, or pemetrexed. The median OS was 8.70 (95% CI: 7.53 to 11.16) and 10.27 months (95% CI: 7.37 to 13.10) for PBC and NPBC (HR: 1.04, 95% CI: .67 – 1.61, p = 0.86), respectively. Multivariable analysis showed an independent prognostic effect on OS for number of previous chemotherapy cycles (3-4 vs. 1-2) (HR: 0.44, 95% CI 0.20 – 0.96, P = 0.03) and whether surgery was performed (HR: 0.44, 95% CI 0.26 – 0.75, P = 0.003). Time from last chemotherapy was not prognostic for OS (HR: 0.99, 95% CI: 0.99 – 1.00, p = 0.19). There were no significant differences for both investigator-designated PFS (HR: 0.84, 95% CI: 0.57 – 1.24, p = .39) and response to chemotherapy between PBC and NPBC (p = 0.57). Conclusions: There is no significant outcome difference between PBC vs. NPBC in patients with metastatic-recurrent urothelial carcinoma who previously received cisplatin-based chemotherapy for locally advanced disease. Those who previously underwent radical surgery or who received 3-4 cycles of cisplatin had better OS with PBC.

PROSPER: Phase III randomized study comparing perioperative nivolumab versus observation in patients with renal cell carcinoma (RCC) undergoing nephrectomy (ECOG-ACRIN EA8143)

TPS5101

Background: There is no standard adjuvant systemic therapy that increases overall survival (OS) over surgery alone for non-metastatic RCC. Anti-PD-1 nivolumab (nivo) improves OS in metastatic RCC and is well tolerated. In mouse models, priming the immune system prior to surgery with anti-PD-1 results in superior OS compared to adjuvant dosing. Remarkable pathologic responses have been seen with neoadjuvant PD-1 in multiple ph 2 studies in bladder, lung and breast cancers. Phase 2 neoadjuvant RCC trials of nivo show preliminary feasibility and safety with no surgical delays. PROSPER RCC seeks to improve clinical outcomes by priming the immune system with neoadjuvant nivo prior to nephrectomy followed by continued immune system engagement with adjuvant blockade in patients (pts) with high risk RCC compared to standard of care surgery alone. Methods: This global, unblinded, phase 3 National Clinical Trials Network study is accruing pts with clinical stage ≥T2 or TanyN+ RCC of any histology planned for radical or partial nephrectomy. Select oligometastatic disease is permitted if the pt can be rendered ‘no evidence of disease’ within 12 weeks of nephrectomy (≤3 metastases; no brain, bone or liver). In the investigational arm, nivo is administered 480mg IV q4 weeks with 1 dose prior to surgery followed by 9 adjuvant doses. The control arm is nephrectomy followed by standard of care surveillance. There is no placebo. Baseline tumor biopsy is required only in the nivo arm but encouraged in both. Randomized pts are stratified by clinical T stage, node positivity, and M stage. 805 pts provide 84.2% power to detect a 14.4% absolute benefit in recurrence-free survival at 5 years assuming the ASSURE historical control of ~56% to 70% (HR = 0.70). The study is powered to evaluate a significant increase in OS (HR 0.67). Critical perioperative therapy considerations such as safety, feasibility, and quality of life metrics are integrated. PROSPER RCC embeds a wealth of translational studies to examine the contribution of the baseline immune milieu and neoadjuvant priming with anti-PD-1 on clinical outcomes. As of February 2020, 396 patients have been enrolled. Clinical trial information: NCT03055013 .

Optimized management of nivolumab (Nivo) and ipilimumab (Ipi) in advanced renal cell carcinoma (RCC): A response-based phase II study (OMNIVORE)

5005

Background: Nivo + Ipi is an established first-line treatment (tx) for advanced RCC. We hypothesized that the addition of CTLA-4 blockade may not be required for all patients (pts). Furthermore, the optimal duration of Nivo maintenance in responding pts is unknown. In this phase II response-adaptive trial, we investigate the sequential addition of 2 doses of Ipi to induce response in Nivo non-responders (NR) and duration of Nivo in responding pts (NCT03203473). Methods: We enrolled pts with advanced RCC with no prior checkpoint inhibitor exposure. All pts received Nivo alone with subsequent arm allocation based on RECISTv1.1 response within 6 months (mos) of tx. Pts with a confirmed partial response (PR) or complete response (CR) within 6 months (mos) discontinued Nivo and were observed (Arm A). Arm A pts reinitiated Nivo if they developed progressive disease (PD); Ipi was added to Nivo if PD persisted or recurred. Pts with stable disease (SD) or PD after no more than 6 mos of Nivo alone received 2 doses of Ipi (Arm B). The primary endpoints were the proportion with PR/CR at 1-year (yr) after Nivo discontinuation (Arm A) and proportion of Nivo NR who convert to PR/CR after adding Ipi (Arm B). Results: 83 pts initiated tx of whom 99% had ECOG 0-1, 96% clear cell RCC, 51% tx-naïve, and 69% IMDC intermediate/poor risk. Median follow-up was 17.0 mos. 15 pts were not allocated to an arm [7 withdrew for PD, 7 withdrew for toxicity, 1 still on tx with unconfirmed PR (uPR)]. At 6 mos, induction Nivo resulted in a confirmed PR in 11% of pts (n=9/83): 12% (n=5/42) tx-naïve, 10% (4/41) prior tx, 8% (n=1/13) favorable risk, 11% (n=8/70) intermediate/poor risk (Table). 11 pts (13%: 9 PR, 1 uPR, 1 SD) were allocated to Arm A, of whom 5 (45%, 90% CI 20-73%) remained off Nivo at ≥ 1 yr. Of 57 pts (69%) allocated to Arm B, 2 pts converted to a PR (4%, 90% CI 1-11%), both of whom had prior tx and PD as best response to Nivo alone. Grade 3-4 treatment related adverse events (TrAE) occurred in 7% (n=6/83) on induction Nivo and in 23% (n=13/57) on Arm B (Nivo + Ipi). Conclusions: We cannot currently recommend a strategy of Nivo followed by response-based addition of Ipi due to the absence of CR and low PR/CR conversion rate (4%). Though a subset of pts treated with Nivo alone can maintain durable responses off tx at 1-yr, early Nivo discontinuation in the absence of toxicity cannot currently be recommended. Investigation into biomarkers to guide tx is ongoing. Clinical trial information: NCT03203473 . [Table: see text]

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.

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.

Prevalence of pathogenic germline cancer risk variants in high-risk urothelial carcinoma

Purpose

To date, there has not been a large, systematic evaluation of the prevalence of germline risk variants in urothelial carcinoma (UC).

Methods

We evaluated the frequency of germline pathogenic and likely pathogenic variants in 1038 patients with high-risk UC who underwent targeted clinical germline testing. Case–control enrichment analysis was performed to screen for pathogenic variant enrichment in 17 DNA repair genes in 1038 UC patients relative to cancer-free individuals.

Results

Among 1038 patients with UC, the cumulative frequency of patients with pathogenic variants was 24%; 18.6% of patients harbored ≥1 actionable germline variant with preventive or therapeutic utility. MSH2 (34/969, 3.5%) and BRCA1/2 (38/867, 4.4%) germline variants had the highest frequency. Germline variants in DNA damage repair genes accounted for 78% of pathogenic germline variants. Compared to the cancer-free cohort, UC patients had significant variant enrichment in MSH2 (odds ratio [OR]: 15.4, 95% confidence interval [CI]: 7.1–32.7, p < 0.0001), MLH1 (OR: 15.9, 95% CI: 4.4–67.7, p < 0.0001), BRCA2 (OR: 5.7, 95% CI: 3.2–9.6, p < 0.0001), and ATM (OR: 3.8, 95% CI: 1.8–8.3, p = 0.02).

Conclusion

In this study, 24% of UC patients harbored pathogenic germline variants and 18.6% had clinically actionable variants. MLH1 and MSH2 were validated as UC risk genes while ATM and BRCA2 were highlighted as potential UC predisposition genes. This work emphasizes the utility of germline testing in selected high-risk UC cohorts.

Results of a Multicenter Phase II Study of Atezolizumab and Bevacizumab for Patients With Metastatic Renal Cell Carcinoma With Variant Histology and/or Sarcomatoid Features

PURPOSE

In this multicenter phase II trial, we evaluated atezolizumab combined with bevacizumab in patients with advanced renal cell carcinoma (RCC) with variant histology or any RCC histology with ≥ 20% sarcomatoid differentiation.

PATIENTS AND METHODS

Eligible patients may have received previous systemic therapy, excluding prior bevacizumab or checkpoint inhibitors. Patients underwent a baseline biopsy and received atezolizumab 1,200 mg and bevacizumab 15 mg/kg intravenously every 3 weeks. The primary end point was overall response rate (ORR) by RECIST version 1.1. Additional end points were progression-free survival (PFS), toxicity, biomarkers of response as determined by programmed death-ligand 1 (PD-L1) status, and on-therapy quality-of-life (QOL) metrics using the Functional Assessment of Cancer Therapy Kidney Symptom Index-19 and the Brief Fatigue Inventory.

RESULTS

Sixty patients received at least 1 dose of either study agent; the majority (65%) were treatment naïve. The ORR for the overall population was 33% and 50% in patients with clear cell RCC with sarcomatoid differentiation and 26% in patients with variant histology RCC. Median PFS was 8.3 months (95% CI, 5.7 to 10.9 months). PD-L1 status was available for 36 patients; 15 (42%) had ≥ 1% expression on tumor cells. ORR in PD-L1-positive patients was 60% (n = 9) v 19% (n = 4) in PD-L1-negative patients. Eight patients (13%) developed treatment-related grade 3 toxicities. There were no treatment-related grade 4-5 toxicities. QOL was maintained throughout therapy.

CONCLUSION

In this study, atezolizumab and bevacizumab demonstrated safety and resulted in objective responses in patients with variant histology RCC or RCC with ≥ 20% sarcomatoid differentiation. This regimen warrants additional exploration in patients with rare RCC, particularly those with PD-L1-positive tumors.

Tumor downstaging as an intermediate endpoint to assess the activity of neoadjuvant systemic therapy in patients with muscle-invasive bladder cancer

BACKGROUND

Achieving a pathologic complete response (pCR) with neoadjuvant chemotherapy (NAC) in patients with muscle-invasive bladder cancer (MIBC) has been associated with improved overall survival (OS). This study was aimed at evaluating the impact of pathologic downstaging (pDS; ie, a pT stage at least 1 stage lower than the pre-NAC cT stage) on the OS of patients with MIBC treated with NAC.

METHODS

The Retrospective International Study of Cancers of the Urothelial Tract (RISC) and the National Cancer Database (NCDB) were queried for cT2-4N0M0 patients treated with NAC. A multivariable Cox model including either pDS or pCR was generated. A nested model was built to evaluate the added value of pDS (excluding patients achieving a pCR) to a model including pCR alone. C indices were computed to assess discrimination. NCDB was used for validation. The treatment effect of NAC versus cystectomy alone in achieving pDS was estimated through an inverse probability-weighted regression adjustment.

RESULTS

Overall, 189 and 2010 patients from the RISC and NCDB cohorts, respectively, were included; pDS and pCR were achieved by 33% and 35% and by 20% and 15% in RISC and NCDB, respectively. In both data sets, pDS and pCR were associated with better OS and C indices. Adding pDS excluding pCR to the model with pCR fit the data better (likelihood ratio, P = .019 for RISC and P < .001 for NCDB), and it yielded better discrimination (incremental C index, 4.2 for RISC and 1.6 for NCDB). The treatment effect of NAC in achieving pDS was 2.07-fold (P < .001) in comparison with cystectomy alone.

CONCLUSIONS

A decrease of at least 1 stage from the cT stage to the pT stage is associated with improved OS in patients with MIBC treated with NAC.

Anti-PD-1 Immunotherapy-Induced Flare of a Known Underlying Relapsing Vasculitis Mimicking Recurrent Cancer

Safe use of immune checkpoint blockade in patients with cancer and autoimmune disorders requires a better understanding of the pathophysiology of immunologic activation. We describe the immune correlates of reactivation of granulomatosis with polyangiitis (GPA)-an antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis-in a patient with metastatic urothelial carcinoma treated with pembrolizumab. After PD-1 blockade, an inflammatory pulmonary nodule demonstrated a granulomatous, CD4+ T-cell infiltrate, correlating with increased CD4+ and CD8+ naïve memory cells in the peripheral blood without changes in other immune checkpoint receptors. Placed within the context of the existing literature on GPA and disease control, our findings suggest a key role for PD-1 in GPA self-tolerance and that selective strategies for immunotherapy may be needed in patients with certain autoimmune disorders. We further summarize the current literature regarding reactivation of autoimmune disorders in patients undergoing immune checkpoint blockade, as well as potential immunosuppressive strategies to minimize the risks of further vasculitic reactivation upon rechallenge with anti-PD-1 blockade. KEY POINTS: Nonspecific imaging findings in patients with cancer and rheumatological disorders may require biopsy to distinguish underlying pathology.Patients with rheumatologic disorders have increased risk of reactivation with PD-(L)1 immune checkpoint blockade, requiring assessment of disease status before starting treatment.Further study is needed to evaluate the efficacy of treatment regimens in preventing and controlling disease reactivation.

The future of perioperative therapy in advanced renal cell carcinoma: how can we PROSPER?

Patients with high-risk renal cell carcinoma (RCC) experience high rates of recurrence despite definitive surgical resection. Recent trials of adjuvant tyrosine kinase inhibitor therapy have provided conflicting efficacy results at the cost of significant adverse events. PD-1 blockade via monoclonal antibodies has emerged as an effective disease-modifying treatment for metastatic RCC. There is emerging data across other solid tumors of the potential efficacy of neoadjuvant PD-1 blockade, and preclinical evidence supporting a neoadjuvant over adjuvant approach. PROSPER RCC is a Phase III, randomized trial evaluating whether perioperative nivolumab increases recurrence-free survival in patients with high-risk RCC undergoing nephrectomy. The neoadjuvant component, intended to prime the immune system for enhanced efficacy, distinguishes PROSPER from other purely adjuvant studies and permits highly clinically relevant translational studies.

Cabozantinib in advanced non-clear-cell renal cell carcinoma: a multicentre, retrospective, cohort study

BACKGROUND

Cabozantinib is approved for patients with metastatic renal cell carcinoma on the basis of studies done in clear-cell histology. The activity of cabozantinib in patients with non-clear-cell renal cell carcinoma is poorly characterised. We sought to analyse the antitumour activity and toxicity of cabozantinib in advanced non-clear-cell renal cell carcinoma.

METHODS

We did a multicentre, international, retrospective cohort study of patients with metastatic non-clear-cell renal cell carcinoma treated with oral cabozantinib during any treatment line at 22 centres: 21 in the USA and one in Belgium. Eligibility required patients with histologically confirmed non-clear-cell renal cell carcinoma who received cabozantinib for metastatic disease during any treatment line roughly between 2015 and 2018. Mixed tumours with a clear-cell histology component were excluded. No other restrictive inclusion criteria were applied. Data were obtained from retrospective chart review by investigators at each institution. Demographic, surgical, pathological, and systemic therapy data were captured with uniform database templates to ensure consistent data collection. The main objectives were to estimate the proportion of patients who achieved an objective response, time to treatment failure, and overall survival after treatment.

FINDINGS

Of 112 identified patients with non-clear-cell renal cell carcinoma treated at the participating centres, 66 (59%) had papillary histology, 17 (15%) had Xp11.2 translocation histology, 15 (13%) had unclassified histology, ten (9%) had chromophobe histology, and four (4%) had collecting duct histology. The proportion of patients who achieved an objective response across all histologies was 30 (27%, 95% CI 19-36) of 112 patients. At a median follow-up of 11 months (IQR 6-18), median time to treatment failure was 6·7 months (95% CI 5·5-8·6), median progression-free survival was 7·0 months (5·7-9·0), and median overall survival was 12·0 months (9·2-17·0). The most common adverse events of any grade were fatigue (58 [52%]), and diarrhoea (38 [34%]). The most common grade 3 events were skin toxicity (rash and palmar-plantar erythrodysesthesia; five [4%]) and hypertension (four [4%]). No treatment-related deaths were observed. Across 54 patients with available next-generation sequencing data, the most frequently altered somatic genes were CDKN2A (12 [22%]) and MET (11 [20%]) with responses seen irrespective of mutational status.

INTERPRETATION

While we await results from prospective studies, this real-world study provides evidence supporting the antitumour activity and safety of cabozantinib across non-clear-cell renal cell carcinomas. Continued support of international collaborations and prospective ongoing studies targeting non-clear-cell renal cell carcinoma subtypes and specific molecular alterations are warranted to improve outcomes across these rare diseases with few evidence-based treatment options.

FUNDING

None.

The Impact of Cisplatin- or Non-Cisplatin-Containing Chemotherapy on Long-Term and Conditional Survival of Patients with Advanced Urinary Tract Cancer

BACKGROUND

The impact of cisplatin use on long-term survival of unselected patients with advanced urinary tract cancer (aUTC) has not been adequately investigated. We used a multinational database to study long-term survival and the impact of treatment type in unselected patients with aUTC.

MATERIALS AND METHODS

A total of 1,333 patients with aUTC (cT4bN0M0, cTanyN+M0, cTanyNanyM+), transitional-cell, squamous, or adenocarcinoma histology who received systemic chemotherapy and had available survival data were selected. Long-term survival was defined as alive at 3 years following initiation of first-line chemotherapy. Conditional overall survival (COS) analysis was employed to study change in prognosis given time survived from initiation of first-line chemotherapy.

RESULTS

Median follow-up was 31.7 months. The combination of cisplatin use and cisplatin eligibility accurately predicted long-term survival. Eligible patients treated with cisplatin conferred a 31.6% probability of 3-year survival (95% confidence interval [CI]: 25.1-38.3), and 2-year COS for patients surviving 3 years after initiation of cisplatin-based chemotherapy was 83% (95% CI: 59.7-93.5). The respective probabilities for patients who were ineligible for cisplatin or not treated with cisplatin despite eligibility were 14% (95% CI: 10.8-17.6) and 49.3% (95% CI: 28.2-67.4). Two-year COS remained significantly different between these two groups up to 3 years after chemotherapy initiation.

CONCLUSION

Cisplatin-based therapy was associated with the highest likelihood of long-term survival in patients with aUTC and should be used in patients who fulfill the established eligibility criteria. Novel therapies are necessary to increase long-term survival in cisplatin-ineligible patients.

IMPLICATIONS FOR PRACTICE

Long-term, disease-free survival is possible in one in four eligible-for-cisplatin patients with advanced urinary tract cancer (aUTC) treated with cisplatin-based combination chemotherapy. Therefore, deviations from eligibility criteria should be avoided. Consolidation surgery should be considered in responders. These data provide benchmarks for the study of novel therapies in aUTC.

Impact of contemporary patterns of chemotherapy utilization on survival in patients with advanced cancer of the urinary tract: a Retrospective International Study of Invasive/Advanced Cancer of the Urothelium (RISC)

Background

Cisplatin-based combination chemotherapy is the standard treatment of advanced urinary tract cancer (aUTC), but 50% of patients are ineligible for cisplatin according to recently published criteria. We used a multinational database to study patterns of chemotherapy utilization in patients with aUTC and determine their impact on survival.

Patients and methods

This was a retrospective study of patients with: UTC (bladder, renal pelvis, ureter or urethra); advanced disease (stages T4b and/or N+ and/or M+); urothelial, squamous or adenocarcinoma histology. Primary objective was overall survival (OS). Eligibility-for-cisplatin was defined by Eastern Cooperative Oncology Group performance status ≤ 1, creatinine clearance ≥ 60 ml/min, no hearing loss, no neuropathy and no heart failure. Cox regression multivariate analyses were used to establish independent associations of cisplatin versus noncisplatin-based chemotherapy on OS.

Results

1794 patients treated between 2000 and 2013 at 29 centers were analyzed. Median follow-up was 29.1 months. About 1333 patients (74%) received first-line chemotherapy: the use of first-line chemotherapy was associated with longer OS: [hazard ratio (HR): 1.91, 95% confidence interval (CI): 1.67-2.20]. Type of first-line chemotherapy received was: cisplatin-based 669 (50%), carboplatin-based 399 (30%) and other 265 (20%). Cisplatin use was an independent favorable prognostic factor (HR: 1.54, 95% CI: 1.35-1.77). This benefit was independent of baseline characteristics or comorbidities but was associated with eligibility-for-cisplatin: eligible patients treated with cisplatin lived longer than those who were not (HR: 1.74, 95% CI: 1.36-2.21), while such benefit was not observed among ineligible patients. About 26% of patients who did not receive cisplatin were eligible for this agent. Median OS of ineligible patients was poor irrespective of the chemotherapy used.

Conclusions

The importance of applying published criteria of eligibility-for-cisplatin was confirmed in a multinational, real-world setting in aUTC. The reasons for deviations from these criteria set targets to improve adherence. Effective therapies for cisplatin-ineligible patients are needed.

Evaluation of Intense Androgen Deprivation Before Prostatectomy: A Randomized Phase II Trial of Enzalutamide and Leuprolide With or Without Abiraterone

PURPOSE

Patients with locally advanced prostate cancer have an increased risk of cancer recurrence and mortality. In this phase II trial, we evaluate neoadjuvant enzalutamide and leuprolide (EL) with or without abiraterone and prednisone (ELAP) before radical prostatectomy (RP) in men with locally advanced prostate cancer.

PATIENTS AND METHODS

Eligible patients had a biopsy Gleason score of 4 + 3 = 7 or greater, prostate-specific antigen (PSA) greater than 20 ng/mL, or T3 disease (by prostate magnetic resonance imaging). Lymph nodes were required to be smaller than 20 mm. Patients were randomly assigned 2:1 to ELAP or EL for 24 weeks followed by RP. All specimens underwent central pathology review. The primary end point was pathologic complete response or minimal residual disease (residual tumor ≤ 5 mm). Secondary end points were PSA, surgical staging, positive margins, and safety. Biomarkers associated with pathologic outcomes were explored.

RESULTS

Seventy-five patients were enrolled at four centers. Most patients had high-risk disease by National Comprehensive Cancer Network criteria (n = 65; 87%). The pathologic complete response or minimal residual disease rate was 30% (n = 15 of 50) in ELAP-treated patients and 16% (n = four of 25) in EL-treated patients (two-sided P = .263). Rates of ypT3 disease, positive margins, and positive lymph nodes were similar between arms. Treatment was well-tolerated. Residual tumors in the two arms showed comparable levels of ERG, PTEN, androgen receptor PSA, and glucocorticoid receptor expression. Tumor ERG positivity and PTEN loss were associated with more extensive residual tumors at RP.

CONCLUSION

Neoadjuvant hormone therapy followed by RP in locally advanced prostate cancer resulted in favorable pathologic responses in some patients, with a trend toward improved pathologic outcomes with ELAP. Longer follow-up is necessary to evaluate the impact of therapy on recurrence rates. The potential association of ERG and PTEN alterations with worse outcomes warrants additional investigation.

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.

Neoadjuvant vs. Adjuvant Chemotherapy in Muscle Invasive Bladder Cancer (MIBC): Analysis From the RISC Database

Background: MIBC is an aggressive disease, with 5-year survival rates ranging from 36 to 48% for p T3/p T4/p N+tumors. Perioperative treatment can improve overall survival, with more robust evidence in favor of neoadjuvant chemotherapy. Few randomized studies have compared neoadjuvant and adjuvant therapy in bladder cancer. Consequently, it has been difficult to establish the benefit of adjuvant chemotherapy (AC) in MIBC. Methods: Data from patients with muscle invasive bladder cancer (>pT2) collected from 2005 to 2012 within the RISC data base (Retrospective International Study of Cancers of the Urothelial Tract) were evaluated. Overall survival (OS), cancer specific survival (CSS), and disease-free survival (DFS) between NC and AC generated using the Kaplan-Meier method were compared for MIBC by log-rank test. All patients in this analysis received either NC or AC. Results: A total of 656 patients with MIBC (325 treated with AC and 331 with NC) were analyzed. The median DFS was 34.6 months (95% CI:25.3-43.9) for NC vs. 24.9 months (95% CI: 19.4-30.5) with AC, with a reduction in the risk of disease progression of 21% in favor of NC (HR: 0.78, 95% CI: 0.63-0.96, P = 0.02). There were no significant differences in terms of CSS (HR: 1.06, 95% CI: 0.79-1.43, P: 0.70), and OS (HR: 1.08, 95% CI: 0.83-1.39, P = 0.57). Conclusions: This study demonstrates superiority in DFS for NC compared to AC. The positive prognostic impact of complete pathological response to NC was confirmed.

Tumor fraction in cell-free DNA as a biomarker in prostate cancer

BACKGROUND

Tumor content in circulating cell-free DNA (cfDNA) is a promising biomarker, but longitudinal dynamics of tumor-derived and non-tumor-derived cfDNA through multiple courses of therapy have not been well described.

METHODS

CfDNA from 663 plasma samples from 140 patients with castration-resistant prostate cancer (CRPC) was subject to sparse whole genome sequencing. Tumor fraction (TFx) estimated using the computational tool ichorCNA was correlated with clinical features and responses to therapy.

RESULTS

TFx associated with the number of bone metastases (median TFx = 0.014 with no bone metastases, 0.047 with 1-3 bone metastases, 0.190 for 4+ bone metastases; P < 0.0001) and with visceral metastases (P < 0.0001). In multivariable analysis, TFx remained associated with metastasis location (P = 0.042); TFx was positively correlated with alkaline phosphatase (P = 0.0227) and negatively correlated with hemoglobin (Hgb) (P < 0.001), but it was not correlated with prostate specific antigen (PSA) (P = 0.75). Tumor-derived and non-tumor-derived cfDNA track together and do not increase with generalized tissue damage from chemotherapy or radiation at the time scales examined. All new treatments that led to ≥30% PSA decline at 6 weeks were associated with TFx decline when baseline TFx was >7%; however, TFx in patients being subsequently maintained on secondary hormonal therapy was quite dynamic.

CONCLUSION

TFx correlates with clinical features associated with overall survival in CRPC, and TFx decline is a promising biomarker for initial therapeutic response.

TRIAL REGISTRATION

Dana-Farber/Harvard Cancer Center (DF/HCC) protocol no. 18-135.

FUNDING

Wong Family Award in Translational Oncology, Dana Farber Cancer Institute Medical Oncology grant, Gerstner Family Foundation, Janssen Pharmaceuticals Inc., and Koch Institute Support (core) grant P30-CA14051 from the National Cancer Institute (NCI).

Adjuvant Vascular Endothelial Growth Factor-targeted Therapy in Renal Cell Carcinoma: A Systematic Review and Pooled Analysis

CONTEXT

Contradictory data exist with regard to adjuvant vascular endothelial growth factor receptor (VEGFR)-targeted therapy in surgically managed patients for localized renal cell carcinoma (RCC).

OBJECTIVE

To systematically evaluate the current evidence regarding the therapeutic benefit (disease-free survival [DFS] and overall survival [OS]) and grade 3-4 adverse events (AEs) for adjuvant VEGFR-targeted therapy for resected localized RCC.

EVIDENCE ACQUISITION

A critical review of PubMed/Medline, Embase, and the Cochrane Library in January 2018 according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement was performed. We identified reports and reviewed them according to the Consolidated Standards of Reporting Trials and Standards for the Reporting of Diagnostic Accuracy Studies criteria. Of eight full-text articles that were eligible for inclusion, five studies (two of five were updated analyses) were retained in the final synthesis. Study characteristics were abstracted and the number needed to treat (NNT) per trial was estimated.

EVIDENCE SYNTHESIS

The three randomized controlled phase III trials included the following comparisons: sunitinib versus placebo or sorafenib versus placebo (Adjuvant Sorafenib or Sunitinib for Unfavorable Renal Carcinoma [ASSURE] study, n=1943), sunitinib versus placebo (S-TRAC, n=615), and pazopanib versus placebo (Pazopanib As Adjuvant Therapy in Localized/Locally Advanced RCC After Nephrectomy study, n=1135). The NNT ranged from 10 (S-TRAC) to 137 (ASSURE study). The pooled analysis showed that VEGFR-targeted therapy was not statistically significantly associated with improved DFS (hazard ratio [HRrandom]: 0.92, 95% confidence interval [CI]: 0.82-1.03, p=0.16) or OS (HRrandom: 0.98, 95% CI: 0.84-1.15, p=0.84) compared with the control group. The adjuvant therapy group experienced significantly higher odds of grade 3-4 AEs (ORrandom: 5.89, 95% CI: 4.85-7.15, p<0.001). In exploratory analyses focusing on patients who started on the full-dose regimen, DFS was improved in patients who received adjuvant therapy (HRrandom: 0.83, 95% CI: 0.73-0.95, p=0.005).

CONCLUSIONS

This pooled analysis of reported randomized trials did not reveal a statistically significant effect between adjuvant VEGFR-targeted therapy and improved DFS or OS in patients with intermediate/high-risk local or regional fully resected RCC. Improvement in DFS may be more likely with the use of full-dose regimens, pending further results. However, adjuvant treatment was associated with high-grade AEs.

PATIENT SUMMARY

Vascular endothelial growth factor receptor-targeted therapy after nephrectomy for localized kidney cancer is not associated with consistent improvements in delaying cancer recurrence or prolonging life and comes at the expense of potentially significant side effects.

Investigating the effect of treatment at high-volume hospitals on overall survival following cytoreductive nephrectomy

PURPOSE

Data revealed the benefit of high-volume care in many complex disease processes. Among patients undergoing nephrectomy, those receiving cytoreductive nephrectomy (CN) for metastatic renal cell cancer (mRCC) constitute a unique subset. They often have a greater medical and surgical complexity. Against this backdrop, we sought to investigate the effect of hospital volume on overall survival among patients undergoing CN for mRCC.

MATERIAL AND METHODS

We identified 11,089 patients who received CN for mRCC in the National Cancer Database from 1998 to 2012. We ranked hospitals based on annual CN volume. Patients who received surgery in hospitals in the top vs. bottom deciles were compared. Inverse Probability of Treatment Weighting (IPTW)-adjusted Kaplan-Meier and Cox regression analyses were used to compare the primary endpoint of overall survival between balanced cohorts of patients. Secondary endpoints were 30-day mortality, 30-day readmissions, and receipt of subsequent systemic therapy.

RESULTS

Median follow-up was 60.39 months (interquartile range [IQR] 35.09-95.95). Median overall survival was 17.61 months (IQR 7.16-44.58). Following propensity score weighting, surgery at a high-volume hospital was associated with a decreased risk of mortality (IPTW-adjusted Cox proportional Hazard Ratio = 0.91; 95% confidence interval: 0.86-0.96). On our IPTW-adjusted Kaplan-Meier analysis, the median survival was 19.94 months (IQR 7.98-50.27) at high-volume hospitals vs. 15.97 months (IQR 6.6-41.56) at low-volume hospitals. With regard to secondary endpoints, the data did not reveal a significant advantage for treatment at a high-volume hospital.

CONCLUSION

We found a significant association between receipt of CN at high-volume hospitals and prolonged overall survival, demonstrated by a nearly 4 month survival benefit.

Everolimus and pazopanib (E/P) benefit genomically selected patients with metastatic urothelial carcinoma

BACKGROUND

Metastatic urothelial carcinoma (mUC) is a genomically diverse disease with known alterations in the mTOR pathway and tyrosine kinases including FGFR. We investigated the efficacy and safety of combination treatment with everolimus and pazopanib (E/P) in genomically profiled patients with mUC.

METHODS

mUC patients enrolled on a Phase I dose escalation study and an expansion cohort treated with E/P were included. The primary end point was objective response rate (ORR); secondary end points were safety, duration of response (DOR), progression-free survival (PFS) and overall survival (OS). Patients were assessed for mutations and copy number alterations in 300 relevant cancer-associated genes using next-generation sequencing and findings were correlated with outcomes. Time-to-event data were estimated with Kaplan-Meier methods.

RESULTS

Of the 23 patients enrolled overall, 19 had mUC. ORR was 21% (one complete response (CR), three partial responses (PR), eight with stable disease (SD). DOR, PFS and OS were 6.5, 3.6, and 9.1 months, respectively. Four patients with clinical benefit (one CR, two PR, one SD) had mutations in TSC1/TSC2 or mTOR and a 5th patient with PR had a FGFR3-TACC3 fusion.

CONCLUSIONS

Combination therapy with E/P is safe in mUC and select patients with alterations in mTOR or FGFR pathways derive significant clinical benefit.

Time of metastatic disease presentation and volume of disease are prognostic for metastatic hormone sensitive prostate cancer (mHSPC)

BACKGROUND

Currently, there is no universally accepted prognostic classification for patients (pts) with metastatic hormone sensitive prostate cancer (mHSPC) treated with androgen deprivation therapy (ADT). Subgroup analyses demonstrated that pts with low volume (LV), per CHAARTED trial definition, mHSPC, and those who relapse after prior local therapy (PLT) have longer overall survival (OS) compared to high volume (HV) and de-novo (DN), respectively. Using a hospital-based registry, we aimed to assess whether a classification based on time of metastatic disease (PLT vs DN) and disease volume (LV vs HV) are prognostic for mHSPC pts treated with ADT.

METHODS

A retrospective cohort of consecutive patients with mHSPC treated with ADT between 1990 and 2013 was selected from the prospectively collected Dana-Farber Cancer Institute database and categorized as DN or PLT and HV or LV, at time of ADT start. Primary and secondary endpoints were OS and time to castration-resistant prostate cancer (CRPC), respectively, which were measured from date of ADT start using Kaplan-Meier method. Multivariable Cox proportional hazards models using known prognostic factors was used.

RESULTS

The analytical cohort consisted of 436 patients. The median OS and time to CRPC for PLT/LV were 92.4 (95%CI: 80.4-127.2) and 25.6 (95%CI: 21-35.7) months and 43.2 (95%CI: 37.2-56.4) and 12.2 (95%CI: 9.8-14.8) months for DN/HV, respectively, whereas intermediate values were observed for PLT/HV and DN/LV. A robust gradient for both outcomes was observed (Trend test P < 0.0001) in the four groups. In a multivariable analysis, DN presentation, HV, and cancer-related pain were independent prognostic factors.

CONCLUSIONS

In our hospital-based registry, time of metastatic presentation and disease volume were prognostic for mHSPC pts treated with ADT. This simple prognostic classification system can aid patient counseling and future trial design.