Repeat Next-Generation Sequencing Testing on Progression in Men With Metastatic Prostate Cancer Can Identify New Actionable Alterations

PURPOSE

There are limited data available on the real-world patterns of molecular testing in men with advanced prostate cancer. We thus sought to evaluate next-generation sequencing (NGS) testing in the United States, focused on single versus serial NGS testing, the different disease states of testing (hormone-sensitive v castration-resistant, metastatic vs nonmetastatic), tissue versus plasma circulating tumor DNA (ctDNA) assays, and how often actionable data were found on each NGS test.

METHODS

The Prostate Cancer Precision Medicine Multi-Institutional Collaborative Effort clinical-genomic database was used for this retrospective analysis, including 1,597 patients across 15 institutions. Actionable NGS data were defined as including somatic alterations in homologous recombination repair genes, mismatch repair deficiency, microsatellite instability (MSI-high), or a high tumor mutational burden ≥10 mut/MB.

RESULTS

Serial NGS testing (two or more NGS tests with specimens collected more than 60 days apart) was performed in 9% (n = 144) of patients with a median of 182 days in between test results. For the second NGS test and beyond, 82.1% (225 of 274) of tests were from ctDNA assays and 76.1% (217 of 285) were collected in the metastatic castration-resistant setting. New actionable data were found on 11.1% (16 of 144) of second NGS tests, with 3.5% (5 of 144) of tests detecting a new BRCA2 alteration or MSI-high. A targeted therapy (poly (ADP-ribose) polymerase inhibitor or immunotherapy) was given after an actionable result on the second NGS test in 31.3% (5 of 16) of patients.

CONCLUSION

Repeat somatic NGS testing in men with prostate cancer is infrequently performed in practice and can identify new actionable alterations not present with initial testing, suggesting the utility of repeat molecular profiling with tissue or blood of men with metastatic castration-resistant prostate cancer to guide therapy choices.

Phase II Study of Erdafitinib in Patients With Tumors With FGFR Amplifications: Results From the NCI-MATCH ECOG-ACRIN Trial (EAY131) Subprotocol K1

PURPOSE

Despite fibroblast growth factor receptor (FGFR) inhibitors being approved in tumor types with select FGFR rearrangements or gene mutations, amplifications of FGFR represent the most common FGFR alteration across malignancies. Subprotocol K1 (EAY131-K1) of the National Cancer Institute-MATCH platform trial was designed to evaluate the antitumor efficacy of the oral FGFR1-4 inhibitor, erdafitinib, in patients with tumors harboring FGFR1-4 amplification.

METHODS

EAY131-K1 was an open-label, single-arm, phase II study with central confirmation of presence of FGFR1-4 amplification in tumors. Patients with urothelial carcinoma were excluded. Enrolled patients received oral erdafitinib at a starting dose of 8 mg once daily continuously with escalation to 9 mg once daily continuously, on the basis of predefined time point assessments of phosphate levels, until disease progression or intolerable toxicity. The primary end point was centrally assessed objective response rate (ORR), with key secondary end points being 6-month progression-free survival (PFS6), PFS, overall survival (OS), and safety.

RESULTS

Thirty-five patients were enrolled into this study with 18 included in the prespecified primary efficacy analysis. The median age of the 18 patients was 60 years, and 78% had received ≥3 previous lines of therapy. There were no confirmed responses to erdafitinib; however, five patients experienced stable disease (SD) as best response. One patient with an FGFR1-amplified breast cancer had a prolonged PFS >168 days (5.5 months). The median PFS was 1.7 months (90% CI, 1.1 to 1.8 months) and the median OS was 4.2 months (90% CI, 2.3 to 9.3 months). The estimated PFS6 rate was 13.8% (90% CI, 3.3 to 31.6). The majority of toxicities were grade 1 to 2 in nature, although there was one grade 5 treatment-related adverse event.

CONCLUSION

Erdafitinib did not meet its primary end point of efficacy as determined by ORR in treatment-refractory solid tumors harboring FGFR1-4 amplifications. Our findings support that rearrangements and gene mutations, but not amplifications, of FGFR remain the established FGFR alterations with approved indications for FGFR inhibition.

Novel Approaches with HIF-2α Targeted Therapies in Metastatic Renal Cell Carcinoma

Germline inactivation of the Von Hippel-Lindau (VHL) tumor suppressor is the defining hallmark in hereditary VHL disease and VHL-associated renal cell carcinoma (RCC). However, somatic VHL mutations are also observed in patients with sporadic RCC. Loss of function VHL mutations result in constitutive activation of hypoxia-inducible factor-2 alpha (HIF-2α), which leads to increased expression of HIF target genes that promote angiogenesis and tumor growth. As of 2023, belzutifan is currently the only approved HIF-2α inhibitor for both VHL-associated and sporadic metastatic RCC (mRCC). However, there is potential for resistance with HIF-2α inhibitors which warrants novel HIF-2α-targeting strategies. In this review, we discuss the potential resistance mechanisms with belzutifan and current clinical trials evaluating novel combinations of belzutifan with other targeted therapies and immune checkpoint inhibitors which may enhance the efficacy of HIF-2α targeting. Lastly, we also discuss newer generation HIF-2α inhibitors that are currently under early investigation and outline future directions and challenges with HIF-2α inhibitors for mRCC.

Pembrolizumab in Patients With Tumors With High Tumor Mutational Burden: Results From the Targeted Agent and Profiling Utilization Registry Study

PURPOSE

The Targeted Agent and Profiling Utilization Registry (TAPUR) Study is a pragmatic basket trial evaluating antitumor activity of approved targeted agents in patients with advanced cancers harboring potentially actionable genomic alterations. Data from cohorts of patients with high tumor mutational burden (HTMB, defined as ≥9 mutations per megabase) with advanced colorectal cancer (CRC) and other advanced cancers treated with pembrolizumab are reported.

METHODS

Eligible patients were 18 years and older with measurable tumors and a lack of standard treatment options, an Eastern Cooperative Oncology Group performance status of 0-1, and adequate organ function. The primary end point was disease control (DC), defined as complete or partial response or stable disease (SD) of at least 16-weeks duration. For the CRC cohort, Simon's two-stage design with a null DC rate of 15% versus 35% (power = 0.85; α = .10) was used. Low accruing histology-specific cohorts were collapsed into one histology-pooled (HP) cohort. For the HP cohort, the null hypothesis of a DC rate of 15% was rejected if the lower limit of a one-sided 90% CI was >15%. Secondary end points included objective response (OR), safety, progression-free survival, overall survival, duration of response, and duration of SD.

RESULTS

Seventy-seven patients with HTMB with CRC (n = 28) or advanced cancers (n = 49) were treated with pembrolizumab. For the CRC cohort, the DC rate was 31% (P = .04) and the OR rate was 11%. For the HP cohort, the DC rate was 45% (one-sided 90% CI, 35 to 100) and the OR rate was 26%. The null hypothesis of a 15% DC rate was rejected for both cohorts. Twelve of 77 patients experienced treatment-related grade 3 adverse events (AEs) or serious AEs, including two deaths.

CONCLUSION

Pembrolizumab demonstrated antitumor activity in pretreated patients with advanced cancers and HTMB.

Adjuvant everolimus after surgery for renal cell carcinoma (EVEREST): a double-blind, placebo-controlled, randomised, phase 3 trial

BACKGROUND

Patients undergoing resection of renal cell carcinoma are at risk of disease relapse. We evaluated the effectiveness of the mammalian target of rapamycin inhibitor everolimus administered after surgery.

METHODS

In this randomised, double-blind, phase 3 trial, we enrolled adults with histologically confirmed renal cell carcinoma who had undergone a full surgical resection and were at intermediate-high or very high risk of recurrence at 398 academic and community institution centres in the USA. After nephrectomy, patients were randomly assigned (1:1) via a central web-based application using a dynamic balancing algorithm to receive 10 mg oral everolimus daily or placebo for 54 weeks. The primary endpoint was recurrence-free survival. Efficacy analyses included all eligible, randomly assigned patients; safety analysis included all patients who received treatment. This trial is registered with ClinicalTrials.gov, NCT01120249 and is closed to new participants.

FINDINGS

Between April 1, 2011, and Sept 15, 2016, a total of 1545 patients were randomly assigned to receive everolimus (n=775) or placebo (n=770), of whom 755 assigned to everolimus and 744 assigned to placebo were eligible for inclusion in the efficacy analysis. With a median follow-up of 76 months (IQR 61-92), recurrence-free survival was longer with everolimus than with placebo (5-year recurrence-free survival 67% [95% CI 63-70] vs 63% [60-67]; stratified log-rank p=0·050; stratified hazard ratio [HR] 0·85, 95% CI 0·72-1·00; p=0·051) but did not meet the prespecified p value for statistical significance of 0·044. Recurrence-free survival was longer with everolimus than with placebo in the very-high-risk group (HR 0·79, 95% CI 0·65-0·97; p=0·022) but not in the intermediate-high-risk group (0·99, 0·73-1·35; p=0·96). Grade 3 or higher adverse events occurred in 343 (46%) of 740 patients who received everolimus and 79 (11%) of 723 who received placebo.

INTERPRETATION

Postoperative everolimus did not improve recurrence-free survival compared with placebo among patients with renal cell carcinoma at high risk of recurrence after nephrectomy. These results do not support the adjuvant use of everolimus for renal cell carcinoma after surgery.

FUNDING

US National Institutes of Health, National Cancer Institute, National Clinical Trials Network, Novartis Pharmaceuticals Corporation, and The Hope Foundation.

Biomarker-Directed Therapy in Black and White Men With Metastatic Castration-Resistant Prostate Cancer

Importance

Black men have higher incidence and mortality from prostate cancer. Whether precision oncology disparities affect Black men with metastatic castration-resistant prostate cancer (mCRPC) is unknown.

Objective

To compare precision medicine data and outcomes between Black and White men with mCRPC.

Design, Setting, and Participants

This retrospective cohort study used data collected by the Prostate Cancer Precision Medicine Multi-Institutional Collaborative Effort (PROMISE) consortium, a multi-institutional registry with linked clinicogenomic data, from April 2020 to December 2021. Participants included Black and White patients with mCRPC with molecular data. Data were analyzed from December 2021 to May 2023.

Exposures

Database-reported race and ethnicity.

Main Outcomes and Measures

The primary outcome was the frequency of actionable molecular data, defined as the presence of mismatch repair deficiency (MMRD) or high microsatellite instability (MSI-H), homologous recombination repair deficiency, or tumor mutational burden of 10 mutations per megabase or greater. Secondary outcomes included the frequency of other alterations, the type and timing of genomic testing performed, and use of targeted therapy. Efficacy outcomes were prostate-specific antigen response rate, site-reported radiographic response, and overall survival.

Results

A total of 962 eligible patients with mCRPC were identified, including 204 Black patients (21.2%; median [IQR] age at diagnosis, 61 [55-67] years; 131 patients [64.2%] with Gleason scores 8-10; 92 patients [45.1%] with de novo metastatic disease) and 758 White patients (78.8%; median [IQR] age, 63 [57-69] years; 445 patients [58.7%] with Gleason scores 8-10; 310 patients [40.9%] with de novo metastatic disease). Median (IQR) follow-up from mCRPC was 26.6 (14.2-44.7) months. Blood-based molecular testing was more common in Black men (111 men [48.7%]) than White men (317 men [36.4%]; P < .001). Rates of actionable alterations were similar between groups (65 Black men [32.8%]; 215 White men [29.1%]; P = .35), but MMRD or MSI-H was more common in Black men (18 men [9.1]) than White men (36 men [4.9%]; P = .04). PTEN alterations were less frequent in Black men than White men (31 men [15.7%] vs 194 men [26.3%]; P = .003), as were TMPRSS alterations (14 men [7.1%] vs 155 men [21.0%]; P < .001). No other differences were seen in the 15 most frequently altered genes, including TP53, AR, CDK12, RB1, and PIK3CA. Matched targeted therapy was given less frequently in Black men than White men (22 men [33.5%] vs 115 men [53.5%]; P = .008). There were no differences in response to targeted therapy or survival between the two cohorts.

Conclusions and Relevance

This cohort study of men with mCRPC found higher frequency of MMRD or MSI-H and lower frequency of PTEN and TMPRSS alterations in Black men compared with White men. Although Black men received targeted therapy less frequently than White men, no differences were observed in clinical outcomes.

Pathogenic Germline Mutational Landscape in Patients With Renal Cell Carcinoma and Associated Clinicopathologic Features

PURPOSE

A subset of renal cell carcinoma (RCC) cases occur because of a hereditary predisposition. However, the prevalence and profiling of germline alterations in RCC have not been fully characterized. Additionally, clinicopathologic factors associated with pathogenic or likely pathogenic (P/LP) germline variants in patients with RCC remain poorly understood.

METHODS

A retrospective analysis of patients with RCC who underwent genetic evaluation was performed. The frequency of P/LP germline variants and genes was evaluated in this cohort. The association between genetic testing outcomes and clinicopathologic features was also assessed.

RESULTS

A total of 321 patients with RCC who had germline testing were identified. Within this cohort, 42 patients (13.1%) had P/LP variants. Genes with the most frequent germline mutations were FLCN (n = 10, 3.1%), SDHB (n = 4, 1.2%), VHL (n = 4, 1.2%), MLH1 (n = 3, 0.9%), and CHEK2 (n = 4, 1.2%). Among patients with P/LP variants, 19 (45.2%) had a potentially targetable mutation. The presence of bilateral or multifocal tumors was associated with P/LP variants (P = .0012 and P = .0098, respectively). Patients who had targeted gene testing had higher rates of P/LP variants compared with multigene panel testing (P = .015). Age and family history of cancers (RCC and non-RCC) did not have any statistically significant association with germline testing outcomes.

CONCLUSION

Among patients with RCC, unselected for a known familial predisposition, 13.4% had P/LP variants. Almost half of patients with P/LP variants had a potentially targetable mutation. Targeted gene panel testing is a feasible option for patients, particularly if syndromic features are present. Age and family history were not associated with P/LP variants. Future studies are needed to optimize current genetic evaluation criteria to expand the detection of patients with RCC who may have germline mutations.

Characterization of Patients With Metastatic Renal Cell Carcinoma Experiencing Complete Response to First-line Therapies: Results From the International Metastatic Renal Cell Carcinoma Database Consortium

PURPOSE

Clinical trials have demonstrated higher complete response rates in the immuno-oncology-based combination arms than in the tyrosine kinase inhibitor arms in patients with metastatic renal cell carcinoma. We aimed to characterize real-world patients who experienced complete response to the contemporary first-line therapies.

MATERIALS AND METHODS

Using the International Metastatic Renal Cell Carcinoma Database Consortium, response-evaluable patients who received frontline immuno-oncology-based combination therapy or tyrosine kinase inhibitor monotherapy were analyzed. Baseline characteristics of patients and post-landmark overall survival were compared based on best overall response, as per RECIST 1.1.

RESULTS

A total of 52 (4.6%) of 1,126 and 223 (3.0%) of 7,557 patients experienced complete response to immuno-oncology-based and tyrosine kinase inhibitor therapies, respectively (P = .005). An adjusted odds ratio for complete response achieved by immuno-oncology-based combination therapy (vs tyrosine kinase inhibitor monotherapy) was 1.56 (95% CI 1.11-2.17; P = .009). Among patients who experienced complete response, the immuno-oncology-based cohort had a higher proportion of non-clear cell histology (15.9% and 4.7%; P = .016), sarcomatoid dedifferentiation (29.8% and 13.5%; P = .014), and multiple sites of metastases (80.4% and 50.0%; P < .001) than the tyrosine kinase inhibitor cohort. Complete response was independently associated with post-landmark overall survival benefit in both the immuno-oncology-based and tyrosine kinase inhibitor cohorts, giving respective adjusted hazard ratios of 0.17 (95% CI 0.04-0.72; P = .016) and 0.28 (95% CI 0.21-0.38; P < .001).

CONCLUSIONS

The complete response rate was not as high in the real-world population as in the clinical trial population. Among those who experienced complete response, several adverse clinicopathological features were more frequently observed in the immuno-oncology-based cohort than in the tyrosine kinase inhibitor cohort. Complete response was an indicator of favorable overall survival.

Differential responses to taxanes and PARP inhibitors in ATM- versus BRCA2-mutated metastatic castrate-resistant prostate cancer

BACKGROUND

PARP (poly(ADP-ribose) polymerase) inhibitors (PARPi) are now standard of care in metastatic castrate-resistant prostate cancer (mCRPC) patients with select mutations in DNA damage repair (DDR) pathways, but patients with ATM- and BRCA2 mutations may respond differently to PARPi. We hypothesized that differences may also exist in response to taxanes, which may inform treatment sequencing decisions.

METHODS

mCRPC patients (N = 158) with deleterious ATM or BRCA2 mutations who received taxanes, PARPi, or both were retrospectively identified from 11 US academic centers. Demographic, treatment, and survival data were collected. Kaplan-Meier analyses were performed and Cox hazard ratios (HR) were calculated for progression-free survival (PFS) as well as overall survival (OS), from time of first taxane or PARPi therapy.

RESULTS

Fifty-eight patients with ATM mutations and 100 with BRCA2 mutations were identified. Fourty-four (76%) patients with ATM mutations received taxane only or taxane before PARPi, while 14 (24%) received PARPi only or PARPi before taxane. Patients with ATM mutations had longer PFS when taxane was given first versus PARPi given first (HR: 0.74 [95% confidence interval [CI]: 0.37-1.50]; p = 0.40). Similarly, OS was longer in patients with ATM mutations who received taxane first (HR: 0.56 [CI: 0.20-1.54]; p = 0.26). Among patients with BRCA2 mutations, 51 (51%) received taxane first and 49 (49%) received PARPi first. In contrast, patients with BRCA2 mutations had longer PFS when PARPi was given first versus taxane given first (HR: 0.85 [CI: 0.54-1.35]; p = 0.49). Similarly, OS was longer in patients with BRCA2 mutations who received PARPi first (HR: 0.75 [CI: 0.41-1.37]; p = 0.35).

CONCLUSIONS

Our retrospective data suggest differential response between ATM and BRCA2 mutated prostate cancers in terms of response to PARPi and to taxane chemotherapy. When considering the sequence of PARPi versus taxane chemotherapy for mCRPC with DDR mutations, ATM, and BRCA2 mutation status may be helpful in guiding choice of initial therapy.

Case report: Immune-mediated meibomian gland dysfunction following pembrolizumab therapy for advanced urothelial carcinoma

Ocular immune-related adverse events are a relatively rare complication of immune checkpoint inhibitors. Common ocular toxicities range from dry eyes to inflammatory uveitis and ocular myasthenia gravis. Here, we present the case of a 55-year-old woman with recurrent urothelial carcinoma of the ureter after initially being managed with neoadjuvant cisplatin-based chemotherapy and surgical resection. She was treated with pembrolizumab which was complicated by immune-mediated pneumonitis after the eighth cycle, which was managed with a prolonged steroid course. The patient also developed red eyes along with recurrent styes. Eye examination revealed decreased tear breakup time, expression of thick and turbid meibum, and meibomian gland atrophy on infrared meibography. The patient was diagnosed with suspected immune-mediated meibomian gland dysfunction (MGD) as a result of pembrolizumab, a previously unreported complication of immunotherapy. The goal of MGD therapy is to stabilize the tear film and minimize evaporation with lipid-based lubricants and other conservative treatments.

Efficacy of enfortumab vedotin in advanced urothelial cancer: Analysis from the Urothelial Cancer Network to Investigate Therapeutic Experiences (UNITE) study

BACKGROUND

Enfortumab vedotin (EV) is a novel antibody-drug conjugate approved for advanced urothelial cancer (aUC) refractory to prior therapy. In the Urothelial Cancer Network to Investigate Therapeutic Experiences (UNITE) study, the authors looked at the experience with EV in patient subsets of interest for which activity had not been well defined in clinical trials.

METHODS

UNITE was a retrospective study of patients with aUC treated with recently approved agents. This initial analysis focused on patients treated with EV. Patient data were abstracted from chart reviews by investigators at each site. The observed response rate (ORR) was investigator-assessed for patients with at least 1 post-baseline scan or clear evidence of clinical progression. ORRs were compared across subsets of interest for patients treated with EV monotherapy.

RESULTS

The initial UNITE analysis included 304 patients from 16 institutions; 260 of these patients were treated with EV monotherapy and included in the analyses. In the monotherapy cohort, the ORR was 52%, and it was >40% in all reported subsets of interest, including patients with comorbidities previously excluded from clinical trials (baseline renal impairment, diabetes, and neuropathy) and patients with fibroblast growth factor receptor 3 (FGFR3) alterations. Progression-free survival and overall survival were 6.8 and 14.4 months, respectively. Patients with a pure urothelial histology had a higher ORR than patients with a variant histology component (58% vs 42%; P = .06).

CONCLUSIONS

In a large retrospective cohort, responses to EV monotherapy were consistent with data previously reported in clinical trials and were also observed in various patient subsets, including patients with variant histology, patients with FGFR3 alterations, and patients previously excluded from clinical trials with an estimated glomerular filtration rate < 30 mL/min and significant comorbidities.

LAY SUMMARY

Enfortumab vedotin, approved by the Food and Drug Administration in 2019, is an important new drug for the treatment of patients with advanced bladder cancer. This study looks at the effectiveness of enfortumab vedotin as it has been used at multiple centers since approval, and focuses on important patient populations previously excluded from clinical trials. These populations include patients with decreased kidney function, diabetes, and important mutations. Enfortumab vedotin is effective for treating these patients. Previously reported clinical trial data have been replicated in this real-world setting, and support the use of this drug in broader patient populations.

Differential Activity of PARP Inhibitors in BRCA1- Versus BRCA2-Altered Metastatic Castration-Resistant Prostate Cancer

Two poly (ADP-ribose) polymerase (PARP) inhibitors (olaparib and rucaparib) are US Food and Drug Administration-approved for patients with metastatic castration-resistant prostate cancer (mCRPC) harboring BRCA1/2 mutations, but the relative efficacy of PARP inhibition in BRCA1- versus BRCA2-altered mCRPC is understudied.

METHODS

We conducted a multicenter retrospective analysis involving 12 sites. We collected genomic and clinical data from 123 patients with BRCA1/2-altered mCRPC who were treated with PARP inhibitors. The primary efficacy end point was the prostate-specific antigen (PSA) response (≥ 50% PSA decline) rate. Secondary end points were PSA progression-free survival (PSA-PFS), clinical or radiographic PFS, and overall survival. We compared clinical outcomes, and other genomic characteristics, among BRCA1- versus BRCA2-altered mCRPC.

RESULTS

A total of 123 patients (13 BRCA1 and 110 BRCA2) were included. PARP inhibitors used were olaparib (n = 116), rucaparib (n = 3), talazoparib (n = 2), and veliparib (n = 2). At diagnosis, 72% of patients had Gleason 8-10 disease. BRCA1 patients were more likely to have metastatic disease at presentation (69% v 37%; P = .04). Age, baseline PSA, metastatic distribution, and types of previous systemic therapies were similar between groups. There were equal proportions of germline mutations (51% v 46%; P = .78) in both groups. BRCA1 patients had more monoallelic (56% v 41%; P = .49) and concurrent TP53 (55% v 36%; P = .32) mutations. PSA₅₀ responses in BRCA1- versus BRCA2-altered patients were 23% versus 63%, respectively (P = .01). BRCA2 patients achieved longer PSA-PFS (HR, 1.94; 95% CI, 0.92 to 4.09; P = .08), PFS (HR, 2.08; 95% CI, 0.99 to 4.40; P = .05), and overall survival (HR, 3.01; 95% CI, 1.32 to 6.83; P = .008). Biallelic (compared with monoallelic) mutations, truncating (compared with missense) mutations, and absence of a concurrent TP53 mutation were associated with PARP inhibitor sensitivity.

CONCLUSION

PARP inhibitor efficacy is diminished in BRCA1- versus BRCA2-altered mCRPC. This is not due to an imbalance in germline mutations but might be related to more monoallelic mutations and/or concurrent TP53 alterations in the BRCA1 group.

Pembrolizumab in Patients With Metastatic Breast Cancer With High Tumor Mutational Burden: Results From the Targeted Agent and Profiling Utilization Registry (TAPUR) Study

PURPOSE

The TAPUR Study is a phase II basket trial that aims to identify signals of antitumor activity of commercially available targeted agents in patients with advanced cancers harboring genomic alterations known to be drug targets. Results in a cohort of patients with metastatic breast cancer (mBC) with high tumor mutational burden (HTMB) treated with pembrolizumab are reported.

METHODS

Patients with advanced mBC received standard doses of either 2 mg/kg or 200 mg infusions of pembrolizumab every 3 weeks. Simon's two-stage design was used with a primary study end point of disease control (DC) defined as objective response or stable disease of at least 16 weeks duration. If two or more patients in stage I achieved DC, the cohort would enroll 18 additional patients in stage II. Secondary end points include progression-free survival (PFS), overall survival, and safety.

RESULTS

Twenty-eight patients were enrolled from October 2016 to July 2018. All patients' tumors had HTMB ranging from 9 to 37 mutations/megabase. DC and objective response were noted in 37% (95% CI, 21 to 50) and 21% of patients (95% CI, 8 to 41), respectively. Median PFS was 10.6 weeks (95% CI, 7.7 to 21.1); median overall survival was 30.6 weeks (95% CI, 18.3 to 103.3). No relationship was observed between PFS and tumor mutational burden. Five patients experienced ≥ 1 serious adverse event or grade 3 adverse event at least possibly related to pembrolizumab consistent with the product label.

CONCLUSION

Pembrolizumab monotherapy has antitumor activity in heavily pretreated patients with mBC characterized by HTMB. Our findings support the recent US Food and Drug Administration approval of pembrolizumab for treatment of patients with unresectable or metastatic solid tumors with HTMB without alternative treatment options.

Differential treatment outcomes in BRCA1/2-, CDK12-, and ATM-mutated metastatic castration-resistant prostate cancer

BACKGROUND

DNA damage repair mutations (DDRm) are common in patients with metastatic castration-resistant prostate cancer (mCRPC). The optimal standard therapy for this population is not well described.

METHODS

A multi-institutional, retrospective study of patients with mCRPC and DDRm was conducted. Patient data, including systemic therapies and responses, were collected. The decline in prostate-specific antigen ≥ 50% from baseline (PSA50) and overall survival (OS) from the treatment start were compared by mutation and treatment type. A multivariable Cox proportional hazards model for OS was created that controlled for DDRm, first-line treatment received for mCRPC, and clinical factors.

RESULTS

The most common DDRm observed among 149 men with mCRPC were BRCA1/2 (44%), CDK12 (32%), and ATM (15%). The majority received first-line abiraterone (40%) or enzalutamide (30%). The PSA50 rate with first-line abiraterone was lower for CDK12 (52%) than BRCA1/2 (89%; P = .02). After first-line abiraterone or enzalutamide, the median OS was longest with second-line carboplatin-chemotherapy (38 months) in comparison with abiraterone or enzalutamide (33 months), docetaxel (17 months), or cabazitaxel (11 months; P = .02). PSA50 responses to carboplatin-based chemotherapy were higher for BRCA1/2 (79%) than ATM (14%; P = .02) or CDK12 (38%; P = .08). In a multivariable analysis, neither the specific DDRm type nor the first-line treatment was associated with improved OS.

CONCLUSIONS

Responses to standard therapies were generally superior in patients with BRCA1/2 mutations and inferior in patients with ATM or CDK12 mutations. The DDRm type did not independently predict OS. After progression on first-line abiraterone or enzalutamide, carboplatin-based chemotherapy was associated with the longest OS. These findings may inform treatment discussions and clinical trial design and require prospective validation.

Characterization of outcomes in patients with advanced genitourinary malignancies treated with immune checkpoint inhibitors

PURPOSE

Several immune checkpoint inhibitors (ICIs) are FDA approved for treatment of genitourinary (GU) malignancies. We aim to determine demographic and clinicopathologic characteristics that significantly affect clinical outcomes in patients with advanced stage GU malignancies treated with ICIs.

MATERIALS AND METHODS

We performed a single-center, consecutive, retrospective cohort analysis on patients with metastatic or unresectable GU malignancies who were treated with ICIs at the University of Michigan. Immune-related adverse events (irAEs), putative immune-mediated allergies, and overall response rates (ORR) were assessed. Comorbidity index scores were calculated. Survival analysis was performed to evaluate progression-free survival (PFS) and overall survival (OS), stratifying and controlling for a variety of clinicopathologic baseline factors including site of metastases.

RESULTS

A total of 160 patients were identified with advanced renal cell carcinoma (RCC) or urothelial carcinoma. Median PFS and OS were 5.0 and 23.6 months for RCC, and 2.8 and 9.6 months for urothelial carcinoma, respectively. Patients who experienced increased frequency and higher grade irAEs had better ICI treatment response (P < 0.0001). Presence of liver metastases was associated with poor response to ICI therapy (P = 0.001). Multivariable modeling demonstrates that patients with urothelial carcinoma and liver metastases had statistically worse PFS and OS compared to patients with RCC or other sites of metastases, respectively.

CONCLUSION

Greater frequency and higher grades of irAEs are associated with better treatment response in patients with RCC and urothelial malignancy receiving ICI therapy. The presence of liver metastases denotes a negative predictive marker for immunotherapy efficacy.

SUMMARY

Immune checkpoint inhibitors (ICI) are increasingly used to treat genitourinary (GU) malignancies. However, clinical data regarding patients with advanced-stage GU malignancies treated with ICI is lacking. Thus, we performed a single-center, retrospective cohort study on patients with metastatic and unresectable renal cell carcinoma (RCC) and urothelial carcinoma who were treated with ICIs at the University of Michigan to provide demographic and clinicopathologic data regarding this population. We specifically focused on immune-related adverse events (irAEs), immune-mediated allergies, and the associated overall response rates (ORR). To better assess performance status, we calculated comorbidity scores for all patients. Finally, survival analyses for progression-free survival (PFS) and overall survival (OS) were performed using Kaplan-Meier analysis and Cox proportional hazards modeling, stratifying and controlling for clinicopathologic baseline factors, including sites of metastases, in our multivariable analysis. A total of 160 patients were identified with advanced RCC or urothelial carcinoma. We found decreased PFS (2.8 vs. 5.0 months) and decreased OS (9.8 vs. 23.6 months) for urothelial carcinoma compared to RCC patients. We noted that patients who experienced increased frequency and higher grades of irAEs had better treatment ORR with ICI therapy (P ≤ 0.0001). The presence of liver metastases was associated with worse ORR (P = 0.001), PFS (P = 0.0014), and OS (P = 0.0028) compared to other sites of metastases including lymph node, lung, and CNS/bone. The poor PFS and OS associated with urothelial carcinoma and liver metastases were preserved in our multivariable modeling after controlling for pertinent clinical factors. We conclude that greater frequency and higher grades of irAEs are associated with better treatment response in GU malignancy patients receiving ICI, a finding that is consistent with published studies in other cancers. The presence of liver metastases represents a significantly poor predictive marker in GU malignancy treated with ICI. Our findings contribute to the growing body of literature that seeks to understand the clinicopathologic variables and outcomes associated with ICI therapy.

American Society of Clinical Oncology Road to Recovery Report: Learning From the COVID-19 Experience to Improve Clinical Research and Cancer Care

This report presents the American Society of Clinical Oncology's (ASCO's) evaluation of the adaptations in care delivery, research operations, and regulatory oversight made in response to the coronavirus pandemic and presents recommendations for moving forward as the pandemic recedes. ASCO organized its recommendations for clinical research around five goals to ensure lessons learned from the COVID-19 experience are used to craft a more equitable, accessible, and efficient clinical research system that protects patient safety, ensures scientific integrity, and maintains data quality. The specific goals are: (1) ensure that clinical research is accessible, affordable, and equitable; (2) design more pragmatic and efficient clinical trials; (3) minimize administrative and regulatory burdens on research sites; (4) recruit, retain, and support a well-trained clinical research workforce; and (5) promote appropriate oversight and review of clinical trial conduct and results. Similarly, ASCO also organized its recommendations regarding cancer care delivery around five goals: (1) promote and protect equitable access to high-quality cancer care; (2) support safe delivery of high-quality cancer care; (3) advance policies to ensure oncology providers have sufficient resources to provide high-quality patient care; (4) recognize and address threats to clinician, provider, and patient well-being; and (5) improve patient access to high-quality cancer care via telemedicine. ASCO will work at all levels to advance the recommendations made in this report.

Immunotherapy in metastatic sarcomatoid renal cell carcinoma: A single institution experience

INTRODUCTION

Immune checkpoint inhibitors (CPIs) were recently approved in advanced clear cell renal cell carcinoma (RCC) and could be a promising option for metastatic RCC with sarcomatoid differentiation (sRCC) which otherwise carry a poor prognosis. We sought to compare outcomes between patients who received immunotherapy (IO) including CPIs or high dose interleukin-2 (HD IL2) for metastatic sRCC versus those who did not.

PATIENTS AND METHODS

We performed a single-center retrospective data analysis of 44 consecutive sRCC patients with any percentage of sarcomatoid differentiation from our institutional RCC database of whom 34 received IO and 10 patients did not.

RESULTS

Baseline variables between the two groups were not significantly different except for a greater percentage of patients with ≥40% sarcomatoid differentiation in the non-IO cohort. At a median follow-up of 27.6 months, patients treated with IO had a median overall survival of 57.6 months compared to 6.6 months in patients not treated with IO (p = 0.0002). Overall response rates (ORR) between the IO and non-IO group were 35.3% and 0% respectively (p = 0.06). When IO was given in the 1st line setting, the ORR was 25.0%, as compared to 44.4% in the 2nd line setting and beyond though limitations of small sample sizes apply. Immune-related adverse events (IRAE) occurred in 38.2% of patients in the IO group, with grade 3 events (mostly gastrointestinal) in 20.6% with no grade 4 or 5 events. IRAEs led to interruption or discontinuation of immunotherapy in 26.5%.

CONCLUSION

Our results support IO as an effective therapeutic option for patients with metastatic sarcomatoid RCC. Further study of various IO regimens, including those affecting the interleukin-2 signaling pathway, and their efficacy in neoadjuvant and adjuvant settings are warranted in sRCC.

The impact of BRAF mutation status on clinical outcomes with anti-PD-1 monotherapy versus combination ipilimumab/nivolumab in treatment-naïve advanced stage melanoma

Nearly half of all metastatic melanoma patients possess the BRAF V600 mutation. Several therapies are approved for advanced stage melanoma, but it is unclear if there is a differential outcome to various immunotherapy regimens based on BRAF mutation status. We retrospectively analyzed a cohort of metastatic or unresectable melanoma patients who were treated with combination ipilimumab/nivolumab (ipi/nivo) or anti-PD-1 monotherapy, nivolumab, or pembrolizumab, as first-line treatment. 235 previously untreated patients were identified in our study. Our univariate analysis showed no statistical difference in progression-free survival (PFS) or overall survival (OS) with ipi/nivo versus anti-PD-1 monotherapy in the BRAF V600 mutant cohort, but there was improved PFS [HR: 0.48, 95% CI, 0.28-0.80] and OS [HR: 0.50, 95% CI, 0.26-0.96] with ipi/nivo compared to anti-PD-1 monotherapy in the BRAF WT group. After adjusting for known prognostic variables in our multivariable analysis, the BRAF WT cohort continued to show PFS and OS benefit with ipi/nivo compared to anti-PD-1 monotherapy. Our single-institution analysis suggests ipi/nivo should be considered over anti-PD-1 monotherapy as the initial immunotherapy regimen for metastatic melanoma patients regardless of BRAF mutation status, but possibly with greater benefit in BRAF WT.

A randomized phase 2 trial of pembrolizumab versus pembrolizumab and acalabrutinib in patients with platinum-resistant metastatic urothelial cancer

Background

Inhibition of the programmed cell death protein 1 (PD‐1) pathway has demonstrated clinical benefit in metastatic urothelial cancer (mUC); however, response rates of 15% to 26% highlight the need for more effective therapies. Bruton tyrosine kinase (BTK) inhibition may suppress myeloid‐derived suppressor cells (MDSCs) and improve T‐cell activation.

Methods

The Randomized Phase 2 Trial of Acalabrutinib and Pembrolizumab Immunotherapy Dual Checkpoint Inhibition in Platinum‐Resistant Metastatic Urothelial Carcinoma (RAPID CHECK; also known as ACE‐ST‐005) was a randomized phase 2 trial evaluating the PD‐1 inhibitor pembrolizumab with or without the BTK inhibitor acalabrutinib for patients with platinum‐refractory mUC. The primary objectives were safety and objective response rates (ORRs) according to the Response Evaluation Criteria in Solid Tumors, version 1.1. Secondary endpoints included progression‐free survival (PFS) and overall survival (OS). Immune profiling was performed to analyze circulating monocytic MDSCs and T cells.

Results

Seventy‐five patients were treated with pembrolizumab (n = 35) or pembrolizumab plus acalabrutinib (n = 40). The ORR was 26% with pembrolizumab (9% with a complete response [CR]) and 20% with pembrolizumab plus acalabrutinib (10% with a CR). The grade 3/4 adverse events (AEs) that occurred in ≥15% of the patients were anemia (20%) with pembrolizumab and fatigue (23%), increased alanine aminotransferase (23%), urinary tract infections (18%), and anemia (18%) with pembrolizumab plus acalabrutinib. One patient treated with pembrolizumab plus acalabrutinib had high MDSCs at the baseline, which significantly decreased at week 7. Overall, MDSCs were not correlated with a clinical response, but some subsets of CD8+ T cells did increase during the combination treatment.

Conclusions

Both treatments were generally well tolerated, although serious AE rates were higher with the combination. Acalabrutinib plus pembrolizumab did not improve the ORR, PFS, or OS in comparison with pembrolizumab alone in mUC. Baseline and on‐treatment peripheral monocytic MDSCs were not different in the treatment cohorts. Proliferating CD8+ T‐cell subsets increased during treatment, particularly in the combination cohort. Ongoing studies are correlating these peripheral immunome findings with tissue‐based immune cell infiltration.

In this randomized phase 2 study of metastatic urothelial cancer, a combination of pembrolizumab and a Bruton tyrosine kinase inhibitor (acalabrutinib) does not improve clinical outcomes in comparison with pembrolizumab alone. Comprehensive flow cytometry is used to evaluate circulating immune cells during treatment.

Nivolumab versus everolimus in patients with advanced renal cell carcinoma: Updated results with long-term follow-up of the randomized, open-label, phase 3 CheckMate 025 trial

BACKGROUND

CheckMate 025 has shown superior efficacy for nivolumab over everolimus in patients with advanced renal cell carcinoma (aRCC) along with improved safety and tolerability. This analysis assesses the long-term clinical benefits of nivolumab versus everolimus.

METHODS

The randomized, open-label, phase 3 CheckMate 025 trial (NCT01668784) included patients with clear cell aRCC previously treated with 1 or 2 antiangiogenic regimens. Patients were randomized to nivolumab (3 mg/kg every 2 weeks) or everolimus (10 mg once a day) until progression or unacceptable toxicity. The primary endpoint was overall survival (OS). The secondary endpoints were the confirmed objective response rate (ORR), progression-free survival (PFS), safety, and health-related quality of life (HRQOL).

RESULTS

Eight hundred twenty-one patients were randomized to nivolumab (n = 410) or everolimus (n = 411); 803 patients were treated (406 with nivolumab and 397 with everolimus). With a minimum follow-up of 64 months (median, 72 months), nivolumab maintained an OS benefit in comparison with everolimus (median, 25.8 months [95% CI, 22.2-29.8 months] vs 19.7 months [95% CI, 17.6-22.1 months]; hazard ratio [HR], 0.73; 95% CI, 0.62-0.85) with 5-year OS probabilities of 26% and 18%, respectively. ORR was higher with nivolumab (94 of 410 [23%] vs 17 of 411 [4%]; P < .001). PFS also favored nivolumab (HR, 0.84; 95% CI, 0.72-0.99; P = .0331). The most common treatment-related adverse events of any grade were fatigue (34.7%) and pruritus (15.5%) with nivolumab and fatigue (34.5%) and stomatitis (29.5%) with everolimus. HRQOL improved from baseline with nivolumab but remained the same or deteriorated with everolimus.

CONCLUSIONS

The superior efficacy of nivolumab over everolimus is maintained after extended follow-up with no new safety signals, and this supports the long-term benefits of nivolumab monotherapy in patients with previously treated aRCC.

LAY SUMMARY

CheckMate 025 compared the effects of nivolumab (a novel immunotherapy) with those of everolimus (an older standard-of-care therapy) for the treatment of advanced kidney cancer in patients who had progressed on antiangiogenic therapy. After 5 years of study, nivolumab continues to be better than everolimus in extending the lives of patients, providing a long-lasting response to treatment, and improving quality of life with a manageable safety profile. The results demonstrate that the clinical benefits of nivolumab versus everolimus in previously treated patients with advanced kidney cancer continue in the long term.

A mutation-specific, single-arm, phase 2 study of dovitinib in patients with advanced malignancies

Background: Receptor tyrosine kinases (RTKs) play key roles in tumorigenesis. The multi-RTK inhibitor dovitinib has demonstrated promising antitumor activity in multiple cancers.

Patients and Methods: In this phase 2, open-label, single-arm study, patients with advanced malignancies with RTK-pathway genetic aberrations whose disease progressed on/following standard treatment received dovitinib (500 mg/day; 5-days-on/2-days-off). The primary endpoint was clinical benefit rate (CBR; complete response, partial response [PR], or stable disease [SD] for ≥ 16 weeks).

Results: Of 80 patients enrolled, common tumors included gastrointestinal stromal tumors (GIST; 20.0%), colorectal cancer (CRC; 18.8%), and ovarian cancer (10.0%). Patients were heavily pretreated (median prior lines = 4; 67.5% had ≥ 3 prior lines). Genetic aberrations included cKIT (28.8%), FGFR3 (15.0%), and RET (15.0%). The CBR was 13.8%; one PR (GIST) and 10 SD (adenoid cystic [n = 3]; ovarian [n = 3]; GIST [n = 2]; CRC [n = 1]; gastroesophageal junction [n = 1]). The most common treatment-related adverse events were fatigue, diarrhea, nausea, and vomiting.

Conclusions: In this heterogeneous patient population, the safety profile was acceptable for dovitinib therapy. A subset of patients with RTK pathway-activated tumors experienced clinical benefit. However, the primary endpoint was not met, suggesting further refinement of predictive biomarkers is required.

Phase Ib/II Clinical Trial of Pembrolizumab With Bevacizumab for Metastatic Renal Cell Carcinoma: BTCRC-GU14-003

PURPOSE

We hypothesized that bevacizumab will potentiate activity of pembrolizumab. We conducted a phase Ib/II, single-arm, multisite clinical trial of the combination in metastatic renal cell carcinoma (RCC).

PATIENTS AND METHODS

Patients with metastatic clear cell RCC who experienced progression after at least one systemic therapy (phase Ib) or were treatment naïve (phase II) were enrolled. In phase Ib, pembrolizumab (200 mg) and bevacizumab (10 or 15 mg/kg) were given intravenously every 3 weeks. The primary end point for phase II was overall response rate (ORR). With an 80% statistical power and a type I error probability of 0.1, 48 patients were to be accrued to detect an ORR of 42%.

RESULTS

Thirteen patients (ages 33-68 years; median, 55 years) were enrolled in the phase Ib study. No dose-limiting toxicities were reported. Pembrolizumab 200 mg and bevacizumab 15 mg/kg were chosen for phase II. Forty-eight patients (ages 42-84 years; median age, 61 years; 33 males) were accrued for the phase II study. The primary end point was met, with the ORR reaching 60.9% (95% CI, 45.4% to 74.9%), consisting of 1 complete response (CR), 2 CRs in target lesions, 25 partial responses, 18 responses of stable disease, 2 unevaluable responses. Median progression-free survival was 20.7 months (95% CI, 11.3 to 27.4 months). Median overall survival was not reached at the median follow-up of 28.3 months. The most common treatment-related grade 3 toxicities were hypertension and proteinuria. There were two grade 4 toxicities: duodenal ulcer and hyponatremia. Presence of tumor-infiltrating T cells, but not programmed death-ligand 1 expression, in tumor tissue correlated with response.

CONCLUSION

The combination of 200 mg of pembrolizumab and a 15 mg/kg dose of bevacizumab given every 3 weeks is safe and active in metastatic RCC.

Clinical Outcomes in Cyclin-dependent Kinase 12 Mutant Advanced Prostate Cancer

BACKGROUND

Cyclin-dependent kinase 12 (CDK12) loss occurs in 3-7% of metastatic prostate cancer patients and is characterized by a genomic instability signature, but the clinical implications of CDK12 loss are not well established.

OBJECTIVE

To determine the clinical course of patients with CDK12 mutant advanced prostate cancer compared with other genomic subtypes.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective analysis of data from three academic medical centers, including 317 patients with advanced prostate cancer and prior next-generation sequencing from tumor tissue (n = 172) or circulating tumor DNA (n = 145), was performed. Forty-six patients had CDK12 mutations; 34 had biallelic CDK12 loss (79%).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Patients were stratified by mutation status (CDK12, homologous recombination deficiency [HRD; BRCA1/2 and ATM], TP53, and other cohort). The Kaplan-Meier method was used to evaluate time to event outcomes: time to development of metastatic disease, time to development of castration resistance, and time to prostate-specific antigen (PSA) progression after first-line androgen receptor pathway inhibitor (ARPI) therapy in a patient subset.

RESULTS AND LIMITATIONS

The median follow-up was 66.6 mo. Patients with CDK12 mutant prostate cancer exhibited shorter time to metastasis (median = 34.9 mo, p =  0.004) and development of castration-resistant disease (median = 32.7 mo, p <  0.001), compared with other genomic subtypes, with shorter time to PSA progression on first-line ARPI treatment of metastatic castration-resistant disease (median = 3.6 mo, p =  0.0219). CDK12 mutant patients did not have overall shorter time on treatment compared with other mutation subgroups, and CDK12 status did not demonstrate statistical significance in multivariate analysis. Limitations include variable center-dependent practice patterns and heterogeneity due to combining tumor and liquid biopsy data.

CONCLUSIONS

Our data suggest that advanced prostate cancers harboring CDK12 mutations display aggressive clinical behavior, underscoring the need to fully delineate the molecular and clinical characteristics, and appropriate therapeutic approaches for distinct subtypes of advanced prostate cancers.

PATIENT SUMMARY

In this report, we evaluate the clinical characteristics and outcomes of patients with prostate cancer and CDK12 mutation in their tumors. These patients seem to have more aggressive disease, with more high-grade Gleason ≥8 cancers and shorter time to developing metastatic cancer. Cases of advanced CDK12-mutated prostate cancer may warrant consideration of therapy intensification or combination approaches.

Real-world outcomes of nivolumab and cabozantinib in metastatic renal cell carcinoma: results from the International Metastatic Renal Cell Carcinoma Database Consortium

Objectives

In the present study, we explored the real-world efficacy of the immuno-oncology checkpoint inhibitor nivolumab and the tyrosine kinase inhibitor cabozantinib in the second-line setting.

Methods

Using the International Metastatic Renal Cell Carcinoma Database Consortium (imdc) dataset, a retrospective analysis of patients with metastatic renal cell carcinoma (mrcc) treated with nivolumab or cabozantinib in the second line after prior therapy targeted to the vascular endothelial growth factor receptor (vegfr) was performed. Baseline characteristics and imdc risk factors were collected. Overall survival (os) and time to treatment failure (ttf) were calculated using Kaplan-Meier curves. Overall response rates (orrs) were determined for each therapy. Multivariable Cox regression analysis was performed to determine survival differences between cabozantinib and nivolumab treatment.

Results

The analysis included 225 patients treated with nivolumab and 53 treated with cabozantinib. No significant difference in median os was observed: 22.10 months [95% confidence interval (ci): 17.18 months to not reached] with nivolumab and 23.70 months (95% ci: 15.52 months to not reached) with cabozantinib (p = 0.61). The ttf was also similar at 6.90 months (95% ci: 4.60 months to 9.20 months) with nivolumab and 7.39 months (95% ci: 5.52 months to 12.85 months) with cabozantinib (p = 0.20). The adjusted hazard ratio (hr) for nivolumab compared with cabozantinib was 1.30 (95% ci: 0.73 to 2.3), p = 0.38. When adjusted by imdc criteria and age, the hr was 1.32 (95% ci: 0.74 to 2.38), p = 0.35.

Conclusions

Real-world imdc data indicate comparable os and ttf for nivolumab and cabozantinib. Both agents are reasonable therapeutic options for patients progressing after initial first-line vegfr-targeted therapy.

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.

Pazopanib with low fat meal (PALM) in advanced renal cell carcinoma

Background Pazopanib is approved for metastatic renal cell carcinoma (RCC). We assessed the safety and efficacy of pazopanib with a low fat meal (LFM): <400 cal and < 20% fat or 10 g per meal. Methods A single arm study of pazopanib with a LFM in 16 adult patients with metastatic RCC with a clear cell component, RECIST 1.1 measurable disease, ECOG PS ≤ 2, and ≤ 3 prior therapies. Pazopanib at 400 mg daily given with LFM for 12 weeks. Incremental dose increases up to 800 mg, or irreversible decreases to 200 mg, allowed every 2 weeks. Primary study endpoint was safety; adverse events (AE) measured per CTCAE version 4.0. Secondary endpoints of RECIST 1.1 response with assessment as 12 weeks; pharmacokinetic (PK) analysis at nine time points, and CYP3A4 polymorphism evaluation. Results Pazopanib with a LFM was well tolerated; 13 of 16 subjects completed all 12 weeks. Three patients withdrew due to adverse events (AEs), with five occurrences of grade 3 AEs. Conclusions Pazopanib with a LFM has acceptable safety and comparable efficacy to fasting administration. Total median pazopanib dose per subject for the study duration was 63.5% of maximum possible conventional dose. A larger study is warranted. Clinical Trial Registration Number: NCT02729194.

Phase II trial of palbociclib in patients with metastatic urothelial cancer after failure of first-line chemotherapy

Background

The majority of urothelial cancers (UC) harbor alterations in retinoblastoma (Rb) pathway genes that can lead to loss of Rb tumour suppressor function. Palbociclib is an oral, selective inhibitor of CDK 4/6 that restores Rb function and promotes cell cycle arrest.

Methods

In this phase II trial, patients with metastatic platinum-refractory UC molecularly selected for p16 loss and intact Rb by tumour immunohistochemistry received palbociclib 125 mg p.o. daily for 21 days of a 28-day cycle. Primary endpoint was progression-free survival at 4 months (PFS4) using a Simon’s two-stage design. Next-generation sequencing including Rb pathway alterations was conducted.

Results

Twelve patients were enrolled and two patients (17%) achieved PFS4 with insufficient activity to advance to stage 2. No responses were seen. Median PFS was 1.9 months (95% CI 1.8–3.7 months) and median overall survival was 6.3 months (95% CI 2.2–12.6 months). Fifty-eight percent of patients had grade ≥3 hematologic toxicity. There were no CDKN2A alterations found and no correlation of Rb pathway alterations with clinical outcome.

Conclusions

Palbociclib did not demonstrate meaningful activity in selected patients with platinum-refractory metastatic UC. Further development of palbociclib should only be considered with improved integral biomarker selection or in rational combination with other therapies.

Epigenetic Reprogramming with Antisense Oligonucleotides Enhances the Effectiveness of Androgen Receptor Inhibition in Castration-Resistant Prostate Cancer

Advanced prostate cancer initially responds to androgen deprivation therapy (ADT), but the disease inevitably recurs as castration-resistant prostate cancer (CRPC). Although CRPC initially responds to abiraterone and enzalutamide, the disease invariably becomes nonresponsive to these agents. Novel approaches are required to circumvent resistance pathways and to extend survival, but the mechanisms underlying resistance remain poorly defined. Our group previously showed the histone lysine-N-methyltransferase EZH2 to be overexpressed in prostate cancer and quantitatively associated with progression and poor prognosis. In this study, we screened a library of epigenetic inhibitors for their ability to render CRPC cells sensitive to enzalutamide and found that EZH2 inhibitors specifically potentiated enzalutamide-mediated inhibition of proliferation. Moreover, we identified antisense oligonucleotides (ASO) as a novel drug strategy to ablate EZH2 and androgen receptor (AR) expression, which may have advantageous properties in certain settings. RNA-seq, chromatin immunoprecipitation sequencing, and assay for transposase-accessible chromatin using sequencing demonstrated that EZH2 inhibition altered the AR cistrome to significantly upregulate AR signaling, suggesting an enhanced dependence of CRPC cells on this pathway following inhibition of EZH2. Combination treatment with ASO targeting EZH2 and AR transcripts inhibited prostate cancer cell growth in vitro and in vivo better than single agents. In sum, this study identifies EZH2 as a critical epigenetic regulator of ADT resistance and defines ASO-based cotargeting of EZH2 and AR as a promising strategy for the treatment of CRPC.Significance: Simultaneous targeting of lysine methyltransferase EZH2 and the AR with ASO proves a novel and effective therapeutic strategy in patients with CRPC. Cancer Res; 78(20); 5731-40. ©2018 AACR.

Use of Bone-Modifying Agents in Myeloma and Bone Metastases: How Recent Dosing Interval Studies Have Affected Our Practice

The management of bone lesions from advanced solid tumors and multiple myeloma typically includes use of a bone-modifying agent to reduce the risk of skeletal-related events. Recent data demonstrate that when using zoledronic acid to reduce the risk of skeletal-related events in metastatic breast cancer, metastatic prostate cancer, and multiple myeloma, the dosing interval of zoledronic acid may be extended from every 4 weeks to every 12 weeks. The ASCO guidelines on the role of bone-modifying agents in metastatic breast cancer and multiple myeloma address zoledronic acid dosing intervals. Herein, we discuss how new data on dosing of bone-modifying agents influence our clinical practice.

Rapid, ultra low coverage copy number profiling of cell-free DNA as a precision oncology screening strategy

Current cell-free DNA (cfDNA) next generation sequencing (NGS) precision oncology workflows are typically limited to targeted and/or disease-specific applications. In advanced cancer, disease burden and cfDNA tumor content are often elevated, yielding unique precision oncology opportunities. We sought to demonstrate the utility of a pan-cancer, rapid, inexpensive, whole genome NGS of cfDNA approach (PRINCe) as a precision oncology screening strategy via ultra-low coverage (~0.01x) tumor content determination through genome-wide copy number alteration (CNA) profiling. We applied PRINCe to a retrospective cohort of 124 cfDNA samples from 100 patients with advanced cancers, including 76 men with metastatic castration-resistant prostate cancer (mCRPC), enabling cfDNA tumor content approximation and actionable focal CNA detection, while facilitating concordance analyses between cfDNA and tissue-based NGS profiles and assessment of cfDNA alteration associations with mCRPC treatment outcomes. Therapeutically relevant focal CNAs were present in 42 (34%) cfDNA samples, including 36 of 93 (39%) mCRPC patient samples harboring AR amplification. PRINCe identified pre-treatment cfDNA CNA profiles facilitating disease monitoring. Combining PRINCe with routine targeted NGS of cfDNA enabled mutation and CNA assessment with coverages tuned to cfDNA tumor content. In mCRPC, genome-wide PRINCe cfDNA and matched tissue CNA profiles showed high concordance (median Pearson correlation = 0.87), and PRINCe detectable AR amplifications predicted reduced time on therapy, independent of therapy type (Kaplan-Meier log-rank test, chi-square = 24.9, p < 0.0001). Our screening approach enables robust, broadly applicable cfDNA-based precision oncology for patients with advanced cancer through scalable identification of therapeutically relevant CNAs and pre-/post-treatment genomic profiles, enabling cfDNA- or tissue-based precision oncology workflow optimization.

Dorsal Muscle Attenuation May Predict Failure to Respond to Interleukin-2 Therapy in Metastatic Renal Cell Carcinoma

RATIONALE AND OBJECTIVES

To explore whether the sarcopenia body type can help predict response to interleukin-2 (IL-2) therapy in metastatic renal cell carcinoma (RCC).

MATERIALS AND METHODS

Institutional review board approval was obtained for this Health Insurance Portability and Accountability Act-compliant retrospective cohort study of 75 subjects with metastatic RCC who underwent pretreatment contrast-enhanced computed tomography within 1 year of initiating IL-2 therapy. Cross-sectional area and attenuation of normal-density (31-100 Hounsfield units [HU]) and low-density (0-30 HU) dorsal muscles were obtained at the T11 vertebral level. The primary outcome was partial or complete response to IL-2 using RECIST 1.1 criteria at 6 weeks. A conditional inference tree was used to determine an optimal HU cutoff for predicting outcome. Bonferroni-adjusted multivariate logistic regression was conducted to investigate the independent associations between imaging features and response after controlling for demographics, doses of IL-2, and RCC prognostic scales (eg, Heng and the Memorial Sloan Kettering Cancer Center [MSKCC]).

RESULTS

Most subjects had intermediate prognosis by Heng (65% [49 of 75]) and the MSKCC (63% [47 of 75]) criteria; 7% had complete response and 12% had partial response. Mean attenuation of low-density dorsal muscles was a significant univariate predictor of IL-2 response after Bonferroni correction (P = 0.03). The odds of responding to treatment were 5.8 times higher for subjects with higher-attenuation low-density dorsal muscles (optimal cutoff: 18.1 HU). This persisted in multivariate analysis (P = 0.02). Body mass index (P = 0.67) and the Heng (P = 0.22) and MSKCC (P = 0.08) clinical prognostic scales were not significant predictors of response.

CONCLUSIONS

Mean cross-sectional attenuation of low-density dorsal muscles (ie, sarcopenia) may predict IL-2 response in metastatic RCC. Clinical variables are poor predictors of response.

Venous Thromboembolism Risk in Patients With Locoregional Urothelial Tract Tumors

BACKGROUND

Venous thromboembolism (VTE) is common in cancer patients, but there is limited data on patients with urothelial tract tumors (UTT). We previously identified several associative factors for increased VTE rates in patients with metastatic UTT. In this study, we assessed the frequency, associative factors, and impact on survival of VTE in patients with locoregional UTT.

METHODS

Patients with locoregional bladder, upper urinary tract, or urethral cancer were included in this multi-center study from 29 academic institutions. Patients with < cT2, > N1, or M1 disease at diagnosis were excluded. Patients with incomplete clinical staging or miscoded/missing data were excluded. Cumulative, unadjusted VTE incidence was calculated from time of diagnosis of muscle-invasive disease, excluding VTEs diagnosed in the metastatic setting. χ2 statistics tested differences in VTE rates across baseline and treatment-related factors. Significant covariates were incorporated into a multivariate, logistic regression model. Overall survival stratified by VTE was estimated using Kaplan-Meier methods and evaluated using the log-rank test.

RESULTS

A total of 1732 patients were eligible. There were 132 (7.6%) VTEs. On multivariate analysis, non-urothelial histology (P < .001), clinical Nx stage (P < .001), cardiovascular disease (P = .01), and renal dysfunction (P = .04) were statistically significant baseline factors associated with VTE. Using surgery alone as reference, surgery with perioperative chemotherapy (P = .04) and radiation with concurrent chemotherapy (P = .04) also were significant.

CONCLUSIONS

The VTE incidence of 7.6% in locoregional disease is comparable with our previously reported rate in the metastatic setting (8.2%). Similar to our findings in metastatic UTT, non-urothelial histology, renal dysfunction, and CVD was associated with increased VTE risk.

Mechanistic Support for Combined MET and AR Blockade in Castration-Resistant Prostate Cancer

A recent phase III trial of the MET kinase inhibitor cabozantinib in men with castration-resistant prostate cancer (CRPC) failed to meet its primary survival end point; however, most men with CRPC have intact androgen receptor (AR) signaling. As previous work supports negative regulation of MET by AR signaling, we hypothesized that intact AR signaling may have limited the efficacy of cabozantinib in some of these patients. To assess the role of AR signaling on MET inhibition, we first performed an in silico analysis of human CRPC tissue samples stratified by AR signaling status ((+) or (-)), which identified MET expression as markedly increased in AR(-) samples. In vitro, AR signaling inhibition in AR(+) CRPC models increased MET expression and resulted in susceptibility to ligand (HGF) activation. Likewise, MET inhibition was only effective in blocking cancer phenotypes in cells with MET overexpression. Using multiple AR(+) CRPC in vitro and in vivo models, we showed that combined cabozantinib and enzalutamide (AR antagonist) treatment was more efficacious than either inhibitor alone. These data provide a compelling rationale to combine AR and MET inhibition in CRPC and may explain the negative results of the phase III cabozantinib study in CRPC. Similarly, the expression of MET in AR(-) disease, whether due to AR inhibition or loss of AR signaling, suggests potential utility for MET inhibition in select patients with AR therapy resistance and in AR(-) prostate cancer.

The Khorana Score in Predicting Venous Thromboembolism for Patients With Metastatic Urothelial Carcinoma and Variant Histology Treated With Chemotherapy

BACKGROUND

The Khorana score is a predictive risk model for venous thromboembolism (VTE) in patients with cancer planning to receive chemotherapy. Urothelial carcinoma and variant histologies (UC/VH) were underrepresented in the model. We sought to evaluate whether the Khorana score predicts for VTE in a retrospective multinational data set of patients with metastatic UC/VH.

METHODS

Patients diagnosed with metastatic UC/VH who received chemotherapy were eligible. Those with incomplete or miscoded data were excluded. Khorana scores were calculated based on the pretreatment data and categorized into high (≥3) or intermediate (1-2) VTE risk. Other patient-, tumor-, and therapy-related factors were also analyzed. The χ² and logistic regression analyses were used to assess differences in VTE rates based on the clinical characteristics. Subgroup analyses were performed to evaluate the Khorana score and associated variables for early (<3 months) and late (>3 months) VTE.

RESULTS

A total of 943 patients were eligible for analysis. The cumulative VTE rate was 9.9%. There was no statistical difference in overall VTE rate between Khorana high- and intermediate-risk groups ( P = .16). In the multivariate analysis, nonurothelial histology (odds ratio [OR] = 2.56; P = .002) and the presence of cardiovascular disease (CVD) or CVD risk factors (OR = 2.14; P = .002) were associated with increased VTE risk. In the first 3 months from initiation of chemotherapy, Khorana high risk (OR = 2.08; P = .04) was associated with higher VTE rates. White blood cell (WBC) count (OR = 1.05; P = .04) was the only significant Khorana variable for early VTE.

CONCLUSIONS

The Khorana score stratifies early but not overall VTE risk in patients with metastatic UC/VH. The WBC count drives the increased early VTE risk seen with the Khorana score.

Genomic Profiling of Penile Squamous Cell Carcinoma Reveals New Opportunities for Targeted Therapy

Penile squamous cell carcinoma (PeSCCA) is a rare malignancy for which there are limited treatment options due to a poor understanding of the molecular alterations underlying disease development and progression. Therefore, we performed comprehensive, targeted next-generation sequencing to identify relevant somatic genomic alterations in a retrospective cohort of 60 fixed tumor samples from 43 PeSCCA cases (including 14 matched primary/metastasis pairs). We identified a median of two relevant somatic mutations and one high-level copy-number alteration per sample (range, 0-5 and 0-6, respectively). Expression of HPV and p16 was detectable in 12% and 28% of patients, respectively. Furthermore, advanced clinical stage, lack of p16 expression, and MYC and CCND1 amplifications were significantly associated with shorter time to progression or PeSCCA-specific survival. Notably, four cases harbored EGFR amplifications and one demonstrated CDK4 amplification, genes for which approved and investigational targeted therapies are available. Importantly, although paired primary tumors and lymph node metastases were largely homogeneous for relevant somatic mutations, we identified heterogeneous EGFR amplification in primary tumor/lymph node metastases in 4 of 14 cases, despite uniform EGFR protein overexpression. Likewise, activating HRAS mutations occurred in 8 of 43 cases. Taken together, we provide the first comprehensive molecular PeSCCA analysis, which offers new insight into potential precision medicine approaches for this disease, including strategies targeting EGFR.

IL-4 induces proliferation in prostate cancer PC3 cells under nutrient-depletion stress through the activation of the JNK-pathway and survivin up-regulation

Interleukin (IL)-4 plays a critical role in the regulation of immune responses and has been detected at high levels in the tumor microenvironment of cancer patients where it correlates with the grade of malignancy. The direct effect of IL-4 on cancer cells has been associated with increased cell survival; however, its role in cancer cell proliferation and related mechanisms is still unclear. Here it was shown that in a nutrient-depleted environment, IL-4 induces proliferation in prostate cancer PC3 cells. In these cells, under nutrient-depletion stress, IL-4 activates mitogen-activated protein kinases (MAPKs), including Erk, p38, and JNK. Using MAP-signaling-specific inhibitors, it was shown that IL-4-induced proliferation is mediated by JNK activation. In fact, JNK-inhibitor-V (JNKi-V) stunted IL-4-mediated cell proliferation. Furthermore, it was found that IL-4 induces survivin up-regulation in nutrient-depleted cancer cells. Using survivin-short-hairpin-RNAs (shRNAs), it was demonstrated that in this milieu survivin expression above a threshold limit is critical to the mechanism of IL-4-mediated proliferation. In addition, the significance of survivin up-regulation in a stressed environment was assessed in prostate cancer mouse xenografts. It was found that survivin knockdown decreases tumor progression in correlation with cancer cell proliferation. Furthermore, under nutrient depletion stress, IL -4 could induce proliferation in cancer cells from multiple origins: MDA-MB-231 (breast), A253 (head and neck), and SKOV-3 (ovarian). Overall, these findings suggest that in a tumor microenvironment under stress conditions, IL-4 triggers a simultaneous activation of the JNK-pathway and the up-regulation of survivin turning on a cancer proliferation mechanism.

Hypomethylating agents for urologic cancers

Silencing of tumor suppressor genes by promoter-region methylation as an epigenetic mechanism of gene regulation is increasingly recognized as beneficial in cancer. Initially developed as cytotoxic high-dose therapies, azacitidine and decitabine are now being reinvestigated in lower-dose cancer treatment regimens with a different paradigm - hypomethylation. Recent evidence for benefit in myelodysplastic syndromes and acute myeloid leukemias has renewed interest in hypomethylation as a therapeutic option in epithelial cancers. In this article, we describe the mechanistic aspects of DNA methylation, which alters gene expression, and review the evidence for hypomethylation as a therapeutic option in urologic cancers. Potential correlative studies that may assist in developing tailored therapy with hypomethylating agents are reviewed. Given that the population with urologic cancers is typically elderly with multiple comorbidities, the excellent tolerability of lower-dose hypomethylating agents provides a high therapeutic index and rational development is warranted, bearing in mind that the cytostatic and delayed activity present challenges in the choice of appropriate trial end points.

Abstract 1345: Interleukin-4 promotes cancer cell proliferation through the activation of the p38-mitotic activated protein kinase (MAPK) signaling pathway

Introduction

There is increasing data supporting the idea that tumor cells take advantage of the signaling molecules of the immune system to proliferate, survive, and invade other tissues. The cytokine, interleukin (IL)-4 plays a critical role in the regulation of immune responses and has been observed at high levels in the tumor microenvironment and in the peripheral blood mononuclear cells of cancer patients, correlating with the grade of malignancy. IL-4 has been associated with increased cell survival in tumor development; however, its effect on cancer cell proliferation has not been thoroughly explored. Here we investigated the signaling pathways activated by IL-4 that induce cancer cell proliferation.

Experimental Procedures

Prostate cancer PC3 cells, breast cancer MDA-MB-231 and salivary gland carcinoma A-253 cells were synchronized by serum starvation and plated in media containing 0.5% FBS alone or in combination with IL-4 (100 ng/ml). Proliferation was assessed using the WST-1 cell viability assay (Roche) and the activated pathways were analyzed with phosphospecific antibodies. Proliferation was also evaluated in PC3 cells treated with MAP kinase kinase (MEK1/2) inhibitor, U0126 (10 µM) or p38 MAPK-specific inhibitor, SB 220025 (0.5 µM) (Calbiochem), alone or in the presence of IL-4.

Results

A time course analysis of cancer cells (PC3, MDA-MB-231 and A-253) stimulated with IL-4 demonstrated an enhanced cell proliferation compared to the untreated cells. To analyze the signaling pathways induced by IL-4 that caused proliferation, PC3 and A253 cells were stimulated with IL-4 and subsequently evaluated by Western blot for the activation of common signaling molecules. It was found that IL-4 significantly enhanced the activation of MAPK/Erk1/2 and the p38 MAPK pathways in both cell types. In contrast, IL-4-dependent activation of Akt signaling was only induced in the PC3 cells. It was further demonstrated that the specific p38-MAPK inhibitor significantly affected the IL-4 induced cell proliferation in PC3 cells. Meanwhile, the MEK1/2 inhibitor (U0126) did not show a significant effect on the proliferation of IL-4 stimulated cells. Inhibition of phospho-p38 by using SB 220025 (0.5 µM) was confirmed by Western Blot.

Conclusions

Increased levels of IL-4 and phosphorylated p38 have been correlated with malignancy in several cancer types. Our results suggest that hyperactivation of p38-MAPK by IL-4 induces a potent proliferation response in various cancer cells from different origins. In addition to its important role in cancer cell survival, we propose that IL-4 enhances cell proliferation via potent activation of p38-MAPK, which is essential in the neoplastic progression. Currently, investigations are underway to further elucidate the interaction of the p38-MAPK signaling with other pathways that could play a critical role in this mechanism.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1345.