HSD3B1 Genotype and Clinical Outcomes in Metastatic Castration-Sensitive Prostate Cancer

Importance

The adrenal-restrictive HSD3B1(1245A) allele limits extragonadal dihydrotestosterone synthesis, whereas the adrenal-permissive HSD3B1(1245C) allele augments extragonadal dihydrotestosterone synthesis. Retrospective studies have suggested an association between the adrenal-permissive allele, the frequency of which is highest in white men, and early development of castration-resistant prostate cancer (CRPC).

Objective

To examine the association between the adrenal-permissive HSD3B1(1245C) allele and early development of CRPC using prospective data.

Design, Setting, and Participants

The E3805 Chemohormonal Therapy vs Androgen Ablation Randomized Trial for Extensive Disease in Prostate Cancer (CHAARTED) was a large, multicenter, phase 3 trial of castration with or without docetaxel treatment in men with newly diagnosed metastatic prostate cancer. From July 28, 2006, through December 31, 2012, 790 patients underwent randomization, of whom 527 had available DNA samples. In this study, the HSD3B1 germline genotype was retrospectively determined in 475 white men treated in E3805 CHAARTED, and clinical outcomes were analyzed by genotype. Data analysis was performed from July 28, 2006, to October 17, 2018.

Interventions

Men were randomized to castration plus docetaxel, 75 mg/m2, every 3 weeks for 6 cycles or castration alone.

Main Outcomes and Measures

Two-year freedom from CRPC and 5-year overall survival, with results stratified by disease volume. Patients were combined across study arms according to genotype to assess the overall outcome associated with genotype. Secondary analyses by treatment arm evaluated whether the docetaxel outcome varied with genotype.

Results

Of 475 white men with DNA samples, 270 patients (56.8%) inherited the adrenal-permissive genotype (≥1 HSD3B1[1245C] allele). Mean (SD) age was 63 (8.7) years. Freedom from CRPC at 2 years was diminished in men with low-volume disease with the adrenal-permissive vs adrenal-restrictive genotype: 51.0% (95% CI, 40.9%-61.2%) vs 70.5% (95% CI, 60.0%-80.9%) (P = .01). Overall survival at 5 years was also worse in men with low-volume disease with the adrenal-permissive genotype: 57.5% (95% CI, 47.4%-67.7%) vs 70.8% (95% CI, 60.3%-81.3%) (P = .03). Hazard ratios were 1.89 (95% CI, 1.13-3.14; P = .02) for CRPC and 1.74 (95% CI, 1.01-3.00; P = .045) for death. There was no association between genotype and outcomes in men with high-volume disease. There was no interaction between genotype and benefit from docetaxel.

Conclusions and Relevance

Inheritance of the adrenal-permissive HSD3B1 genotype is associated with earlier castration resistance and shorter overall survival in men with low-volume metastatic prostate cancer and may help identify men more likely to benefit from escalated androgen receptor axis inhibition beyond gonadal testosterone suppression.

Phase 3 Assessment of the Automated Bone Scan Index as a Prognostic Imaging Biomarker of Overall Survival in Men With Metastatic Castration-Resistant Prostate Cancer: A Secondary Analysis of a Randomized Clinical Trial

Importance

Prostate cancer commonly metastasizes to bone, and bone metastases are associated with pathologic fractures, pain, and reduced survival. Bone disease is routinely visualized using the technetium Tc 99m (99mTc) bone scan; however, the standard interpretation of bone scan data relies on subjective manual assessment of counting metastatic lesion numbers. There is an unmet need for an objective and fully quantitative assessment of bone scan data.

Objective

To clinically assess in a prospectively defined analysis plan of a clinical trial the automated Bone Scan Index (aBSI) as an independent prognostic determinant of overall survival (OS) in men with metastatic castration-resistant prostate cancer (mCRPC).

Design, Setting, and Participants

This investigation was a prospectively planned analysis of the aBSI in a phase 3 multicenter randomized, double-blind, placebo-controlled clinical trial of tasquinimod (10TASQ10). Men with bone metastatic chemotherapy-naïve CRPC were recruited at 241 sites in 37 countries between March 2011 and August 2015. The statistical analysis plan to clinically evaluate the aBSI was prospectively defined and locked before unmasking of the 10TASQ10 study. The analysis of aBSI was conducted between May 25, 2016, and June 3, 2017.

Main Outcomes and Measures

The associations of baseline aBSI with OS, radiographic progression-free survival (rPFS), time to symptomatic progression, and time to opiate use for cancer pain.

Results

Of the total 1245 men enrolled, 721 were evaluable for the aBSI. The mean (SD) age (available for 719 men) was 70.6 (8.0) years (age range, 47-90 years). The aBSI population was representative of the total study population based on baseline characteristics. The aBSI (median, 1.07; range, 0-32.60) was significantly associated with OS (hazard ratio [HR], 1.20; 95% CI, 1.14-1.26; P < .001). The median OS by aBSI quartile (lowest to highest) was 34.7, 27.3, 21.7, and 13.3 months, respectively. The discriminative ability of the aBSI (C index, 0.63) in prognosticating OS was significantly higher than that of the manual lesion counting (C index, 0.60) (P = .03). In a multivariable survival model, a higher aBSI remained independently associated with OS (HR, 1.06; 95% CI, 1.01-1.11; P = .03). A higher aBSI was also independently associated with time to symptomatic progression (HR, 1.18; 95% CI, 1.13-1.23; P < .001) and time to opiate use for cancer pain (HR, 1.21; 95% CI, 1.14-1.30; P < .001).

Conclusions and Relevance

To date, this investigation is the largest prospectively analyzed study to validate the aBSI as an independent prognostic imaging biomarker of survival in mCRPC. These data support the prognostic utility of the aBSI as an objective imaging biomarker in the design and eligibility of clinical trials of systemic therapies for patients with mCRPC.

Trial Registration

ClinicalTrials.gov Identifier: NCT01234311.

Genomic and clinical characterization of pulmonary-only metastatic prostate cancer: A unique molecular subtype

BACKGROUND

Isolated pulmonary involvement is uncommon in metastatic hormone-sensitive prostate cancer (mHSPC). To characterize outcomes and molecular alterations of this unique patient subset, we conducted a retrospective review of patients with hormone-naïve prostate cancer presenting with lung-only metastases.

METHODS

This was a retrospective single-institution study. Medical records of 25 patients presenting with pulmonary-only metastases before receiving androgen deprivation therapy (ADT) were analyzed. Germline and/or somatic genomic results, where available (n = 16), were documented. Tumor tissue was analyzed using clinical-grade next-generation DNA sequencing assays. Clinical endpoints included complete prostate-specific antigen (PSA) response to ADT (<0.1 ng/mL), median overall survival (OS) from time of ADT initiation, median PSA progression-free survival (PSA-PFS), and failure-free survival (FFS) at 4 years.

RESULTS

Baseline characteristics were notable for 48% of men (12 of 25) having first or second-degree relatives with prostate cancer, compared with 20% expected. Complete PSA responses to ADT were noted in 52% of men, with a median PSA-PFS of 66 months, a 4-year FFS rate of 72%, and a median OS that was not reached after 190 months. In evaluable patients, molecular drivers were enriched for mismatch repair mutations (4 of 16, 25%) and homologous-recombination deficiency mutations (4 of 16, 25%). These results are limited by the small sample size and retrospective nature of this analysis.

CONCLUSIONS

This exploratory study represents one of the largest cohorts of lung-only mHSPC patients to-date. The prevalence of actionable DNA-repair gene alterations was higher than anticipated (any DNA-repair mutation: 8 of 16, 50%). Compared to historical data, these patients appear to have exceptional and durable responses to first-line ADT. This study suggests that pulmonary-tropic mHSPC biology may be fundamentally different from nonpulmonary mHSPC.

Nivolumab plus ipilimumab versus sunitinib in first-line treatment for advanced renal cell carcinoma: extended follow-up of efficacy and safety results from a randomised, controlled, phase 3 trial

BACKGROUND

In the ongoing phase 3 CheckMate 214 trial, nivolumab plus ipilimumab showed superior efficacy over sunitinib in patients with previously untreated intermediate-risk or poor-risk advanced renal cell carcinoma, with a manageable safety profile. In this study, we aimed to assess efficacy and safety after extended follow-up to inform the long-term clinical benefit of nivolumab plus ipilimumab versus sunitinib in this setting.

METHODS

In the phase 3, randomised, controlled CheckMate 214 trial, patients aged 18 years and older with previously untreated, advanced, or metastatic histologically confirmed renal cell carcinoma with a clear-cell component were recruited from 175 hospitals and cancer centres in 28 countries. Patients were categorised by International Metastatic Renal Cell Carcinoma Database Consortium risk status into favourable-risk, intermediate-risk, and poor-risk subgroups and randomly assigned (1:1) to open-label nivolumab (3 mg/kg intravenously) plus ipilimumab (1 mg/kg intravenously) every 3 weeks for four doses, followed by nivolumab (3 mg/kg intravenously) every 2 weeks; or sunitinib (50 mg orally) once daily for 4 weeks (6-week cycle). Randomisation was done through an interactive voice response system, with a block size of four and stratified by risk status and geographical region. The co-primary endpoints for the trial were overall survival, progression-free survival per independent radiology review committee (IRRC), and objective responses per IRRC in intermediate-risk or poor-risk patients. Secondary endpoints were overall survival, progression-free survival per IRRC, and objective responses per IRRC in the intention-to-treat population, and adverse events in all treated patients. In this Article, we report overall survival, investigator-assessed progression-free survival, investigator-assessed objective response, characterisation of response, and safety after extended follow-up. Efficacy outcomes were assessed in all randomly assigned patients; safety was assessed in all treated patients. This study is registered with ClinicalTrials.gov, number NCT02231749, and is ongoing but now closed to recruitment.

FINDINGS

Between Oct 16, 2014, and Feb 23, 2016, of 1390 patients screened, 1096 (79%) eligible patients were randomly assigned to nivolumab plus ipilimumab or sunitinib (550 vs 546 in the intention-to-treat population; 425 vs 422 intermediate-risk or poor-risk patients, and 125 vs 124 favourable-risk patients). With extended follow-up (median follow-up 32·4 months [IQR 13·4-36·3]), in intermediate-risk or poor-risk patients, results for the three co-primary efficacy endpoints showed that nivolumab plus ipilimumab continued to be superior to sunitinib in terms of overall survival (median not reached [95% CI 35·6-not estimable] vs 26·6 months [22·1-33·4]; hazard ratio [HR] 0·66 [95% CI 0·54-0·80], p<0·0001), progression-free survival (median 8·2 months [95% CI 6·9-10·0] vs 8·3 months [7·0-8·8]; HR 0·77 [95% CI 0·65-0·90], p=0·0014), and the proportion of patients achieving an objective response (178 [42%] of 425 vs 124 [29%] of 422; p=0·0001). Similarly, in intention-to-treat patients, nivolumab and ipilimumab showed improved efficacy compared with sunitinib in terms of overall survival (median not reached [95% CI not estimable] vs 37·9 months [32·2-not estimable]; HR 0·71 [95% CI 0·59-0·86], p=0·0003), progression-free survival (median 9·7 months [95% CI 8·1-11·1] vs 9·7 months [8·3-11·1]; HR 0·85 [95% CI 0·73-0·98], p=0·027), and the proportion of patients achieving an objective response (227 [41%] of 550 vs 186 [34%] of 546 p=0·015). In all treated patients, the most common grade 3-4 treatment-related adverse events in the nivolumab and ipilimumab group were increased lipase (57 [10%] of 547), increased amylase (31 [6%]), and increased alanine aminotransferase (28 [5%]), whereas in the sunitinib group they were hypertension (90 [17%] of 535), fatigue (51 [10%]), and palmar-plantar erythrodysaesthesia (49 [9%]). Eight deaths in the nivolumab plus ipilimumab group and four deaths in the sunitinib group were reported as treatment-related.

INTERPRETATION

The results suggest that the superior efficacy of nivolumab plus ipilimumab over sunitinib was maintained in intermediate-risk or poor-risk and intention-to-treat patients with extended follow-up, and show the long-term benefits of nivolumab plus ipilimumab in patients with previously untreated advanced renal cell carcinoma across all risk categories.

FUNDING

Bristol-Myers Squibb and ONO Pharmaceutical.

Improved identification of patients with oligometastatic clear cell renal cell carcinoma with PSMA-targeted 18F-DCFPyL PET/CT

OBJECTIVE

Complete surgical resection of metastatic sites has been shown to prolong survival in select patients with oligometastatic RCC. This treatment strategy is dependent upon the accurate characterization of a patient's extent of disease. The objective of this study was to explore the utility of PSMA-targeted ¹⁸F-DCFPyL PET/CT in patients with presumed oligometastatic clear cell RCC.

METHODS

This is a subset analysis of a prospective study in which patients with RCC were imaged with ¹⁸F-DCFPyL PET/CT (ClinicalTrials.gov identifier NCT02687139). In the present analysis, patients with oligometastatic clear cell RCC, defined as ≤ 3 metastatic lesions on conventional imaging, were evaluated. ¹⁸F-DCFPyL PET/CT scans were reviewed for sites of disease and compared to conventional imaging.

RESULTS

The final cohort included 14 patients with oligometastatic clear cell RCC. Conventional imaging revealed 21 metastatic lesions and 3 primary tumors. ¹⁸F-DCFPyL PET/CT detected 29 sites of metastatic disease and 3 primary tumors. Of the 21 metastatic lesions detected on conventional imaging, 17 (81.0%) had radiotracer uptake. Additionally, all 3 primary tumors had radiotracer uptake. In 4 (28.6%) patients a total of 12 more lesions were identified on ¹⁸F-DCFPyL PET/CT than conventional imaging. Notably, 3 (21.4%) patients were no longer considered oligometastatic. The detection rates of conventional imaging and ¹⁸F-DCFPyL PET/CT for identifying sites of disease were 66.7% and 88.9%, respectively.

CONCLUSIONS

PSMA-targeted PET/CT appears to aid in the identification of patients with oligometastatic clear cell RCC. If borne out in future studies, this suggests that PSMA-targeted imaging has the potential to help select candidates for metastasis-directed therapy.

Molecular Characterization and Clinical Outcomes of Primary Gleason Pattern 5 Prostate Cancer After Radical Prostatectomy

PURPOSE

Very high-risk prostate cancer (PC) is associated with poor response to local and systemic treatments; however, few cases have been molecularly profiled. We studied clinical outcomes and molecular profiles of patients with clinically localized primary Gleason pattern 5 PC.

PATIENTS AND METHODS

Clinicopathologic features, targeted somatic and germline sequencing, and PTEN, TP53, and ERG status by immunohistochemistry were assessed in patients undergoing surgery from 2005 to 2015; 60 consecutive patients were identified with Gleason score 5 + 4 = 9 or 5 + 5 = 10 PC after radical prostatectomy with available tissue and clinical follow-up. Clinicopathologic and genomic parameters were correlated with biochemical relapse, metastasis-free survival, time to castration resistance, and overall survival using Cox proportional hazards models.

RESULTS

Of patients with somatic sequencing data and clinical follow-up, 34% had DNA repair gene mutations, including 22% (11 of 49) with homologous recombination and 12% (six of 49) with mismatch repair gene alterations. Homologous recombination mutations were germline in 82% (nine of 11) of patients. In addition, 33% (16 of 49) had TP53 mutation, and 51% (29 of 57) had PTEN loss. Overall, 43% developed metastasis, with a time to castration resistance of 12 months. On multivariable analysis of clinicopathologic variables, only ductal/intraductal histology (hazard ratio, 4.43; 95% CI, 1.76 to 11.15; P = .002) and seminal vesicle invasion (hazard ratio, 5.14; 95% CI, 1.83 to 14.47; P = .002) were associated with metastasis. Among genomic alterations, only TP53 mutation and PTEN loss were associated with metastasis on univariable analysis, and neither remained significant in multivariable analyses. These data are retrospective and hypothesis generating.

CONCLUSION

Potentially actionable homologous recombination and mismatch repair alterations are observed in a significant proportion of patients with very high-risk PC at the time of radical prostatectomy. These findings could inform the design of prospective trials in this patient population.

Predicting Renal Cancer Recurrence: Defining Limitations of Existing Prognostic Models With Prospective Trial-Based Validation

PURPOSE

To validate currently used recurrence prediction models for renal cell carcinoma (RCC) by using prospective data from the ASSURE (ECOG-ACRIN E2805; Adjuvant Sorafenib or Sunitinib for Unfavorable Renal Carcinoma) adjuvant trial.

PATIENTS AND METHODS

Eight RCC recurrence models (University of California at Los Angeles Integrated Staging System [UISS]; Stage, Size, Grade, and Necrosis [SSIGN]; Leibovich; Kattan; Memorial Sloan Kettering Cancer Center [MSKCC]; Yaycioglu; Karakiewicz; and Cindolo) were selected on the basis of their use in clinical practice and clinical trial designs. These models along with the TNM staging system were validated using 1,647 patients with resected localized high-grade or locally advanced disease (≥ pT1b grade 3 and 4/pTanyN1Mo) from the ASSURE cohort. The predictive performance of the model was quantified by assessing its discriminatory and calibration abilities.

RESULTS

Prospective validation of predictive and prognostic models for localized RCC showed a substantial decrease in each of the predictive abilities of the model compared with their original and externally validated discriminatory estimates. Among the models, the SSIGN score performed best (0.688; 95% CI, 0.686 to 0.689), and the UISS model performed worst (0.556; 95% CI, 0.555 to 0.557). Compared with the 2002 TNM staging system (C-index, 0.60), most models only marginally outperformed standard staging. Importantly, all models, including TNM, demonstrated statistically significant variability in their predictive ability over time and were most useful within the first 2 years after diagnosis.

CONCLUSION

In RCC, as in many other solid malignancies, clinicians rely on retrospective prediction tools to guide patient care and clinical trial selection and largely overestimate their predictive abilities. We used prospective collected adjuvant trial data to validate existing RCC prediction models and demonstrate a sharp decrease in the predictive ability of all models compared with their previous retrospective validations. Accordingly, we recommend prospective validation of any predictive model before implementing it into clinical practice and clinical trial design.

Wnt-pathway Activating Mutations Are Associated with Resistance to First-line Abiraterone and Enzalutamide in Castration-resistant Prostate Cancer

BACKGROUND

Wnt signaling is a cellular pathway involved in embryogenesis, development, and neoplasia. Wnt-pathway activation may accelerate prostate cancer androgen-independent growth and mediate antiandrogen resistance. Since 10-20% of advanced prostate cancers harbor Wnt-activating mutations, we aimed to characterize the clinical features and response to novel antiandrogens in such patients.

OBJECTIVE

To determine whether men with metastatic castration-resistant prostate cancer (mCRPC) who harbor Wnt-pathway mutations have poorer responses to first-line novel hormonal therapies: abiraterone/enzalutamide.

DESIGN, SETTING, AND PARTICIPANTS

Patients with mCRPC who received first-line abiraterone or enzalutamide were retrospectively evaluated. Using tumor DNA analyses, we queried for activating mutations in CTNNB1 or inactivating mutations in APC or RNF43, all of which are predicted to stimulate Wnt signaling. Presence or absence of at least one Wnt-activating alteration was correlated with clinical-pathologic characteristics and treatment outcomes.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Time to prostate-specific antigen (PSA) progression, overall survival (OS), and PSA response were measured. Cox regression models were used to test associations between Wnt status and clinical-pathologic outcomes; Kaplan-Meier and log-rank analyses were used to compare time-to-event endpoints.

RESULTS AND LIMITATIONS

Of 137 patients evaluated, 11% (n=15) had tumor DNA analysis showing at least one Wnt-stimulating alteration. Patients with Wnt-activating mutations had numerically fewer T3/T4 tumors than Wnt wild-type patients (31% vs 51%), but were otherwise generally balanced. Median time to PSA progression on first-line abiraterone/enzalutamide was shorter in Wnt-activated patients (6.5 vs 9.6mo, hazard ratio [HR] 2.34, p=0.003), as was OS (23.6 vs 27.7mo, HR 2.28, p=0.01). PSA responses were numerically worse in Wnt-activated patients (53% vs 75%, p=0.12). Presence of Wnt-activating alterations (adjusted HR [aHR] 2.33, p=0.007) and use of previous chemotherapy (aHR 1.83, p=0.004) were both independently associated with increased hazard of progression.

CONCLUSIONS

Patients with somatic Wnt-pathway activating mutations have worse outcomes to first-line abiraterone/enzalutamide than Wnt wild-type patients. Our data suggest that additional genomically informed therapies are needed for this relevant subset of mCRPC patients.

PATIENT SUMMARY

In this report, we retrospectively examined outcomes of metastatic prostate cancer patients with or without Wnt-pathway mutations who received abiraterone or enzalutamide for the first time, in order to examine whether these mutations affect the prognosis. Our study suggested that patients who have Wnt-pathway activating mutations derived less benefit from abiraterone and enzalutamide when compared to patients without these mutations. We conclude that Wnt-pathway mutations might decrease the effectiveness of abiraterone and enzalutamide, and we propose that the Wnt pathway might be a good therapeutic target for these patients, in order to potentially reverse or prolong resistance to abiraterone and enzalutamide in men with Wnt mutations.

Factors Affecting Combination Trial Success (FACTS): Investigator Survey Results on Early-Phase Combination Trials

Experimental therapeutic oncology agents are often combined to circumvent tumor resistance to individual agents. However, most combination trials fail to demonstrate sufficient safety and efficacy to advance to a later phase. This study collected survey data on phase 1 combination therapy trials identified from ClinicalTrials.gov between January 1, 2003 and November 30, 2017 to assess trial design and the progress of combinations toward regulatory approval. Online surveys (N = 289, 23 questions total) were emailed to Principal Investigators (PIs) of early-phase National Cancer Institute and/or industry trials; 263 emails (91%) were received and 113 surveys completed (43%). Among phase 1 combination trials, 24.9% (95%CI: 15.3%, 34.4%) progressed to phase 2 or further; 18.7% (95%CI: 5.90%, 31.4%) progressed to phase 3 or regulatory approval; and 12.4% (95%CI: 0.00%, 25.5%) achieved regulatory approval. Observations of “clinical promise” in phase 1 combination studies were associated with higher rates of advancement past each milestone toward regulatory approval (cumulative OR = 11.9; p = 0.0002). Phase 1 combination study designs were concordant with Clinical Trial Design Task Force (CTD-TF) Recommendations 79.6% of the time (95%CI: 72.2%, 87.1%). Most discordances occurred where no plausible pharmacokinetic or pharmacodynamic interactions were expected. Investigator-defined “clinical promise” of a combination is associated with progress toward regulatory approval. Although concordance between study designs of phase 1 combination trials and CTD-TF Recommendations was relatively high, it may be beneficial to raise awareness about the best study design to use when no plausible pharmacokinetic or pharmacodynamic interactions are expected.

Risk of development of visceral metastases subsequent to abiraterone vs placebo: An analysis of mode of radiographic progression in COU-AA-302

BACKGROUND

Abiraterone increases survival in prostate cancer, but tumors resistant to abiraterone can exhibit a hormonally resistant, aggressive phenotype. We hypothesized that the therapeutic pressure of abiraterone is resulting in more clinically aggressive disease at progression, characterized by increased visceral metastases. Our objective was to determine whether abiraterone increased the risk of development of visceral metastases at the time of progression compared with placebo in a randomized phase III trial.

METHODS

We performed a post hoc analysis of the COU-AA-302 trial of abiraterone plus prednisone vs placebo plus prednisone in patients with metastatic castration-resistant prostate cancer. The primary outcome was the development of visceral metastases. The cumulative incidences of visceral metastases were calculated by the Kaplan-Meier method and compared using log-rank testing. Multivariable Cox regression analysis assessed for the independent association of abiraterone with the development of visceral metastases.

RESULTS

Eighty-four of 1088 patients developed visceral metastases during study. Log-rank testing and Cox regression showed no difference in time to visceral metastases between groups (HR 1.01 [95% confidence interval (CI), 0.65-1.56]; P = .97). Abiraterone treatment was not associated with the development of visceral metastases in multivariable analysis (HR 0.89 [95% CI, 0.57-1.40]; P = .62). The study was limited by censoring of radiographic outcomes at the time of completion of primary study therapy; longer term risks were not assessed.

CONCLUSIONS

Abiraterone was not associated with increased risk of visceral metastatic disease at the time of progression compared with placebo.

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.

Genetic Alterations Detected in Cell-Free DNA Are Associated With Enzalutamide and Abiraterone Resistance in Castration-Resistant Prostate Cancer

PURPOSE

Androgen receptor (AR) gene alterations, including ligand-binding domain mutations and copy number (CN) gain, have yet to be fully established as predictive markers of resistance to enzalutamide and abiraterone in men with metastatic castration-resistant prostate cancer (mCRPC). The goal of this study was to validate AR gene alterations detected in cell-free DNA (cfDNA) as markers of enzalutamide and abiraterone resistance in patients with mCRPC.

METHODS

Patients with mCRPC (N = 62) were prospectively enrolled between 2014 and 2018. Blood was collected before therapies-enzalutamide (n = 25), abiraterone (n = 35), or enzalutamide and abiraterone (n = 2)-and at disease progression. We used deep next-generation sequencing to analyze cfDNA for sequence variants and CN status in AR and 45 additional cancer-associated genes. Primary end points were prostate-specific antigen response, progression-free survival (PFS), and overall survival (OS).

RESULTS

Elevated tumor-specific cfDNA (circulating tumor DNA) was associated with a worse prostate-specific antigen response (hazard ratio [HR], 3.17; 95% CI, 1.11 to 9.05; P = .031), PFS (HR, 1.76; 95% CI, 1.03 to 3.01; P = .039), and OS (HR, 2.92; 95% CI, 1.40 to 6.11; P = .004). AR ligand-binding domain missense mutations (HR, 2.51; 95% CI, 1.15 to 5.72; P = .020) were associated with a shorter PFS in multivariable models. AR CN gain was associated with a shorter PFS; however, significance was lost in multivariable modeling. Genetic alterations in tumor protein p53 (HR, 2.70; 95% CI, 1.27 to 5.72; P = .009) and phosphoinositide 3-kinase pathway defects (HR, 2.62; 95% CI, 1.12 to 6.10; P = .026) were associated with a worse OS in multivariable models.

CONCLUSION

These findings support the conclusion that high circulating tumor DNA burden is associated with worse outcomes to enzalutamide and abiraterone in men with mCRPC. Tumor protein p53 loss and phosphoinositide 3-kinase pathway defects were associated with worse OS in men with mCRPC. AR status associations with outcomes were not robust, and additional validation is needed.

Muscadine grape skin extract inhibits prostate cancer cells by inducing cell-cycle arrest, and decreasing migration through heat shock protein 40

Previously we demonstrated that muscadine grape skin extract (MSKE), a natural product, significantly inhibited androgen-responsive prostate cancer cell growth by inducing apoptosis through the targeting of survival pathways. However, the therapeutic effect of MSKE on more aggressive androgen-independent prostate cancer remains unknown. This study examined the effects of MSKE treatment in metastatic prostate cancer using complementary PC-3 cells and xenograft model. MSKE significantly inhibited PC-3 human prostate cancer cell tumor growth in vitro and in vivo. The growth-inhibitory effect of MSKE appeared to be through the induction of cell-cycle arrest. This induction was accompanied by a reduction in the protein expression of Hsp40 and cell-cycle regulation proteins, cyclin D1 and NF-kBp65. In addition, MSKE induced p21 expression independent of wild-type p53 induced protein expression. Moreover, we demonstrate that MSKE significantly inhibited cell migration in PC-3 prostate cancer cells. Overall, these results demonstrate that MSKE inhibits prostate tumor growth and migration, and induces cell-cycle arrest by targeting Hsp40 and proteins involved in cell-cycle regulation and proliferation. This suggests that MSKE may also be explored either as a neo-adjuvant or therapeutic for castration resistant prostate cancer.

Immune-related adverse events with immune checkpoint inhibitors affecting the skeleton: a seminal case series

Background

The use of immune checkpoint inhibitors is increasing in cancer therapy today. It is critical that treatment teams become familiar with the organ systems potentially impacted by immune-related adverse events associated with these drugs. Here, we report adverse skeletal effects of immunotherapy, a phenomenon not previously described.

Case presentations

In this retrospective case series, clinical, laboratory and imaging data were obtained in patients referred to endocrinology or rheumatology with new fractures (n = 3) or resorptive bone lesions (n = 3) that developed while on agents targeting PD-1, CTLA-4 or both. The average age of patients was 59.3 (SD 8.6), and five were male. Cancer types included melanoma, renal cell carcinoma and non-small cell lung cancer. All fracture patients had vertebral compression, and two of the three had multiple fracture sites involved. Sites of resorptive lesions included the shoulder, hand and clavicle. Biochemically, elevated or high-normal markers of bone resorption were seen in five of the six patients. Erythrocyte sedimentation rate was elevated in three of the four patients where checked.

Conclusions

This case series represents the first description of potential skeletal adverse effects related to immune checkpoint inhibitors. These findings are important for providers caring for patients who experience musculoskeletal symptoms and may merit additional evaluation.

Efficacy of Radium-223 in Bone-metastatic Castration-resistant Prostate Cancer with and Without Homologous Repair Gene Defects

BACKGROUND

Pathogenic mutations in genes mediating homologous recombination (HR) DNA repair are present in 20-30% of men with metastatic castrate-resistant prostate cancer (mCRPC). Radium-223 is a bone-seeking α-emitter that induces double-strand DNA breaks, thereby killing cancer cells in the bone microenvironment.

OBJECTIVE

To evaluate the potential impact of germline or somatic HR-deficiency (HRD) mutations on radium-223 efficacy in mCRPC with bone metastasis.

DESIGN, SETTING, AND PARTICIPANTS

This is a retrospective single-institution study. Medical records of 190 mCRPC patients for whom germline and/or somatic DNA sequencing data were available were reviewed. Of these patients, 28 had received standard-of-care radium-223 at Johns Hopkins between February 2013 and February 2018.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Alkaline phosphatase (ALP) responses and time-to-ALP-progression were the coprimary endpoints. Prostate-specific antigen (PSA) responses, overall survival (OS), and time to next systemic therapy were also evaluated.

RESULTS AND LIMITATIONS

Of the 28 patients included, 10 men (35.7%) had a germline/somatic HRD mutation (three in BRCA2, and one each in ATM, ATR, CHEK2, FANCG, FANCI, FANCL, and PALB2) and 18 (64.3%) did not. Men with HRD mutations (HRD+) had numerically lower ages (66 vs 73yr, p=0.25), more soft-tissue metastases (50% vs 38%, p=0.43), and higher baseline ALP levels (130 vs 108 U/l, p=0.84). Compared with HRD(-) men, HRD(+) patients showed greater ALP responses (80% vs 39%, p=0.04), longer time to ALP progression (median10.4 vs 5.8mo, hazard ratio [HR] 6.4, p=0.005), and a trend toward longer OS (median 36.9 vs 19.0mo, HR 3.3, p=0.11). PSA responses (0% vs 0%, p>0.99) and time to next systemic therapy (HR 1.5, p=0.39) were similar between the two groups. Results are limited by the retrospective nature of the analysis and the small sample size.

CONCLUSIONS

In this exploratory study, bone-metastatic CRPC patients with inactivating HRD mutations demonstrated significantly improved ALP responses and time to ALP progression. These results should motivate prospective validation of the "synthetic lethality" hypothesis between HRD mutations and radium-223 activity.

PATIENT SUMMARY

In this report, we retrospectively examined outcomes to metastatic prostate cancer in patients with and without DNA repair mutations who received radium-223, a therapy that kills cancer cells by causing direct DNA damage. Our study suggested that patients who have inherited or acquired DNA repair gene mutations derived greater benefit from radium-223 when compared with patients without these mutations. We concluded that radium-223 might have an important role in this setting; however, prospective studies are needed to confirm whether DNA repair mutations truly make radium-223 work better or not.

Ipilimumab plus nivolumab and DNA-repair defects in AR-V7-expressing metastatic prostate cancer

AR-V7-expressing metastatic prostate cancer is an aggressive phenotype with poor progression-free survival (PFS) and overall survival (OS). Preliminary evidence suggests that AR-V7-positive tumors may be enriched for DNA-repair defects, perhaps rendering them more sensitive to immune-checkpoint blockade. We enrolled 15 metastatic prostate cancer patients with AR-V7-expressing circulating tumor cells into a prospective phase-2 trial. Patients received nivolumab 3 mg/kg plus ipilimumab 1 mg/kg every 3 weeks for four doses, then maintenance nivolumab 3 mg/kg every 2 weeks. Targeted next-generation sequencing was performed to determine DNA-repair deficiency (DRD) status. Outcomes included PSA response rates, objective response rates (ORR), PSA progression-free survival (PSA-PFS), clinical/radiographic PFS and OS. Median age of participants was 65, median PSA was 115 ng/mL, 67% had visceral metastases, and 60% had ≥4 prior systemic therapies. Six of 15 men (40%) had DRD mutations (three in BRCA2, two in ATM, one in ERCC4; none had microsatellite instability). Overall, the PSA response rate was 2/15 (13%), ORR was 2/8 (25%) in those with measurable disease, median PSA-PFS was 3.0 (95%CI 2.1-NR) months, PFS was 3.7 (95%CI 2.8-7.5) months, and OS was 8.2 (95%CI 5.5-10.4) months. Outcomes appeared generally better in DRD+ vs. DRD- tumors with respect to PSA responses (33% vs. 0%; P=0.14, nonsignificant), ORR (40% vs. 0%; P=0.46, nonsignificant), PSA-PFS (HR 0.19; P<0.01, significant), PFS (HR 0.31; P=0.01, significant), and OS (HR 0.41; P=0.11, nonsignificant). There were no new safety concerns. Ipilimumab plus nivolumab demonstrated encouraging efficacy in AR-V7-positive prostate cancers with DRD mutations, but not in the overall study population.

Patient-reported outcomes for patients with metastatic castration-resistant prostate cancer receiving docetaxel and Atrasentan versus docetaxel and placebo in a randomized phase III clinical trial (SWOG S0421)

Background

SWOG S0421 was a large randomized trial comparing docetaxel/prednisone plus placebo (DPP) to docetaxel/prednisone plus atrasentan over 12 cycles for patients with metastatic castration-resistant prostate cancer (mCRPC). The current report presents the PRO results for this trial, an important secondary endpoint.

Methods

The trial specified two primary PRO endpoints. Palliation of worst pain was based on the Brief Pain Inventory (BPI), where a 2 point difference is defined as clinically meaningful. Improvement of functional status was based on the Functional Assessment of Cancer Therapy – Prostate Cancer Trial Outcome Index (FACT-P TOI); a 5-point difference has been defined as clinically meaningful. We compared rates by arm using chi-square tests. Longitudinal analyses using linear mixed models addressed changes by arm over time.

Results

Four-hundred eighty-nine patients on each arm were evaluable for PRO endpoint data. There were no differences by arm in clinically meaningful pain palliation (41.7% for DPP vs. 44.0% for DPA, p = .70) or functional status (24.2% for DPP vs. 28.7% for DPA, p = .13). Longitudinal comparisons indicated no differences over time by arm for BPI Worst Pain scores (0.13 points, p = .23). Patients on the DPA arm had improved functional status of 1.78 points on average, a statistically significant (p = .02) but not clinically meaningful difference.

Conclusions

The SWOG S0421 PRO data showed little evidence of clinically meaningful differences by arm in either pain palliation or functional status.

Electronic supplementary material

The online version of this article (10.1186/s41687-018-0054-5) contains supplementary material, which is available to authorized users.

Quality of Life During Treatment With Chemohormonal Therapy: Analysis of E3805 Chemohormonal Androgen Ablation Randomized Trial in Prostate Cancer

Purpose Chemohormonal therapy with docetaxel and androgen deprivation therapy (ADT+D) for metastatic hormone-sensitive prostate cancer improves overall survival as compared with androgen deprivation therapy (ADT) alone. We compared the quality of life (QOL) between patients with metastatic hormone-sensitive prostate cancer who were treated with ADT+D and those who were treated with ADT alone. Methods Men were randomly assigned to ADT+ D (six cycles) or to ADT alone. QOL was assessed by Functional Assessment of Cancer Therapy-Prostate (FACT-P), FACT-Taxane, Functional Assessment of Chronic Illness Therapy-Fatigue, and the Brief Pain Inventory at baseline and at 3, 6, 9, and 12 months. The Wilcoxon signed rank test was used to examine changes over time. Mixed-effect models compared the QOL between arms at each time point. Results Seven hundred ninety men were randomly assigned (ADT+D [n = 397] and ADT[ n = 393]) and completed FACT-P (90% at baseline, 86% at 3 months, 83% at 6 months, 78% at 9 months, and 77% at 12 months). ADT+D patients reported a statistically significant decline in FACT-P at 3 months ( P < .001) but FACT-P did not differ significantly between baseline and 12 months ( P = .38). ADT+D FACT-P scores were significantly lower at 3 months ( P = .02) but significantly higher at 12 months ( P = .04) when compared with ADT FACT-P scores. Differences did not exceed the minimal clinically important difference at any time point. ADT+D patients reported significantly lower Functional Assessment of Chronic Illness Therapy-Fatigue scores at 3 months than did ADT patients ( P < .001). Over time, both arms reported significantly poorer FACT-Taxane scores ( P < .001) when compared with baseline. Brief Pain Inventory scores were similar between arms. Conclusion Although ADT+D was associated with statistically worse QOL at 3 months, QOL was better at 12 months for ADT+D patients than for ADT patients. Both arms reported a similar minimally changed QOL over time, suggesting that ADT+D is not associated with a greater long-term negative impact on QOL.

Chemohormonal Therapy in Metastatic Hormone-Sensitive Prostate Cancer: Long-Term Survival Analysis of the Randomized Phase III E3805 CHAARTED Trial

Purpose Docetaxel added to androgen-deprivation therapy (ADT) significantly increases the longevity of some patients with metastatic hormone-sensitive prostate cancer. Herein, we present the outcomes of the CHAARTED (Chemohormonal Therapy Versus Androgen Ablation Randomized Trial for Extensive Disease in Prostate Cancer) trial with more mature follow-up and focus on tumor volume. Patients and Methods In this phase III study, 790 patients with metastatic hormone-sensitive prostate cancer were equally randomly assigned to receive either ADT in combination with docetaxel 75 mg/m2 for up to six cycles or ADT alone. The primary end point of the study was overall survival (OS). Additional analyses of the prospectively defined low- and high-volume disease subgroups were performed. High-volume disease was defined as presence of visceral metastases and/or ≥ four bone metastases with at least one outside of the vertebral column and pelvis. Results At a median follow-up of 53.7 months, the median OS was 57.6 months for the chemohormonal therapy arm versus 47.2 months for ADT alone (hazard ratio [HR], 0.72; 95% CI, 0.59 to 0.89; P = .0018). For patients with high-volume disease (n = 513), the median OS was 51.2 months with chemohormonal therapy versus 34.4 months with ADT alone (HR, 0.63; 95% CI, 0.50 to 0.79; P < .001). For those with low-volume disease (n = 277), no OS benefit was observed (HR, 1.04; 95% CI, 0.70 to 1.55; P = .86). Conclusion The clinical benefit from chemohormonal therapy in prolonging OS was confirmed for patients with high-volume disease; however, for patients with low-volume disease, no OS benefit was discerned.

Burden of Metastatic Castrate Naive Prostate Cancer Patients, to Identify Men More Likely to Benefit from Early Docetaxel: Further Analyses of CHAARTED and GETUG-AFU15 Studies

BACKGROUND

Docetaxel (D) at the time of starting androgen deprivation therapy (ADT) for metastatic castrate naive prostate cancer shows a clear survival benefit for patients with high-volume (HV) disease. It is unclear whether patients with low-volume (LV) disease benefit from early D.

OBJECTIVE

To define the overall survival (OS) of aggregate data of patient subgroups from the CHAARTED and GETUG-AFU15 studies, defined by metastatic burden (HV and LV) and time of metastasis occurrence (at diagnosis or after prior local treatment [PRLT]).

DESIGN, SETTING, AND PARTICIPANTS

Data were accessed from two independent phase III trials of ADT alone or ADT+D-GETUG-AFU15 (N=385) and CHAARTED (N=790), with median follow-ups for survivors of 83.2 and 48.2 mo, respectively. The definition of HV and LV disease was harmonized.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary end point was OS.

RESULTS AND LIMITATIONS

Meta-analysis results of the aggregate data showed significant heterogeneity in ADT+D versus ADT effect sizes between HV and LV subgroups (p=0.017), and failed to detect heterogeneity in ADT+D versus ADT effect sizes between upfront and PRLT subgroups (p=0.4). Adding D in patients with HV disease has a consistent effect in improving median OS (HV-ADT: 34.4 and 35.1 mo, HV-ADT+D: 51.2 and 39.8 mo in CHAARTED and GETUG-AFU15, respectively; pooled average hazard ratio or HR (95% confidence interval [CI]) 0.68 ([95% CI 0.56; 0.82], p<0.001). Patients with LV disease showed much longer OS, without evidence that D improved OS (LV-ADT: not reached [NR] and 83.4; LV-ADT+D: 63.5 and NR in CHAARTED and GETUG-AFU15, respectively; pooled HR (95% CI) 1.03 (95% CI 0.77; 1.38). Aggregate data showed no evidence of heterogeneity of early D in LV and HV subgroups irrespective of whether patients had PRLT or not. Post hoc subgroup analysis was based on aggregated data from two independent phase III randomized trials.

CONCLUSIONS

There was no apparent survival benefit in the CHAARTED and GETUG-AFU15 studies with D for LV. Across both studies, early D showed consistent effect and improved OS in HV patients.

PATIENT SUMMARY

Patients with a higher burden of metastatic prostate cancer starting androgen deprivation therapy (ADT) have a poorer prognosis and are more likely to benefit from early docetaxel. Low-volume patients have longer overall survival with ADT alone, and the toxicity of docetaxel may outweigh its benefits.

Seven-Month Prostate-Specific Antigen Is Prognostic in Metastatic Hormone-Sensitive Prostate Cancer Treated With Androgen Deprivation With or Without Docetaxel

Purpose We evaluated the relationship between prostate-specific antigen (PSA) and overall survival in the context of a prospectively randomized clinical trial comparing androgen-deprivation therapy (ADT) plus docetaxel with ADT alone for initial metastatic hormone-sensitive prostate cancer. Methods We performed a landmark survival analysis at 7 months using the E3805 Chemohormonal Therapy Versus Androgen Ablation Randomized Trial for Extensive Disease in Prostate Cancer (CHAARTED) database ( ClinicalTrials.gov identifier: NCT00309985). Inclusion required at least 7 months of follow-up and PSA levels at 7 months from ADT initiation. We used the prognostic classifiers identified in a previously reported trial (Southwest Oncology Group 9346) of PSA ≤ 0.2, > 0.2 to 4, and > 4 ng/mL. Results Seven hundred nineteen of 790 patients were eligible for this subanalysis; 358 were treated with ADT plus docetaxel, and 361 were treated with ADT alone. Median follow-up time was 23.1 months. On multivariable analysis, achieving a 7-month PSA ≤ 0.2 ng/mL was more likely with docetaxel, low-volume disease, prior local therapy, and lower baseline PSAs (all P ≤ .01). Across all patients, median overall survival was significantly longer if 7-month PSA reached ≤ 0.2 ng/mL compared with > 4 ng/mL (median survival, 60.4 v 22.2 months, respectively; P < .001). On multivariable analysis, 7-month PSA ≤ 0.2 and low volume disease were prognostic of longer overall survival (all P < 0.01). The addition of docetaxel increased the likelihood of achieving a PSA ≤ 0.2 ng/mL at 7 months (45.3% v 28.8% of patients on ADT alone). Patients on ADT alone who achieved a 7-month PSA ≤ 0.2 ng/mL had the best survival and were more likely to have low-volume disease (56.7%). Conclusion PSA ≤ 0.2 ng/mL at 7 months is prognostic for longer overall survival with ADT for metastatic hormone-sensitive prostate cancer irrespective of docetaxel administration. Adding docetaxel increased the likelihood of a lower PSA and improved survival.

Bipolar androgen therapy in men with metastatic castration-resistant prostate cancer after progression on enzalutamide: an open-label, phase 2, multicohort study

BACKGROUND

Prostate cancer that progresses after enzalutamide treatment is poorly responsive to further antiandrogen therapy, and paradoxically, rapid cycling between high and low serum testosterone concentrations (bipolar androgen therapy [BAT]) in this setting might induce tumour responses. We aimed to evaluate BAT in patients with metastatic castration-resistant prostate cancer that progressed after enzalutamide.

METHODS

We did this single-centre, open-label, phase 2, multicohort study in the USA. We included patients aged 18 years or older who had histologically confirmed and radiographically documented metastatic castration-resistant prostate cancer, with no more than two previous second-line hormonal therapies, and a castrate concentration of testosterone. Patients were asymptomatic, with Eastern Cooperative Oncology Group performance status of 0-2, and did not have high-risk lesions for tumour flare (eg, >5 sites of visceral disease or bone lesions with impending fracture). For the cohort reported here, we required patients to have had progression on enzalutamide with a continued prostate-specific antigen (PSA) rise after enzalutamide treatment discontinuation. Patients received BAT, which consisted of intramuscular testosterone cipionate 400 mg every 28 days until progression and continued luteinising hormone-releasing hormone agonist therapy. Upon progression after BAT, men were rechallenged with oral enzalutamide 160 mg daily. The co-primary endpoints were investigator-assessed 50% decline in PSA concentration from baseline (PSA50) for BAT (for all patients who received at least one dose) and for enzalutamide rechallenge (based on intention-to-treat analysis). These data represent the final analysis for the post-enzalutamide cohort, while two additional cohorts (post-abiraterone and newly castration-resistant prostate cancer) are ongoing. The trial is registered with ClinicalTrials.gov, number NCT02090114.

FINDINGS

Between Aug 28, 2014, and May 18, 2016, we accrued 30 eligible patients and treated them with BAT. Nine (30%; 95% CI 15-49; p<0·0001) of 30 patients achieved a PSA50 to BAT. 29 patients completed BAT and 21 proceeded to enzalutamide rechallenge, of whom 15 (52%; 95% CI 33-71; p<0·0001) achieved a PSA50 response. During BAT, the only grade 3-4 adverse event occurring in more than one patient was hypertension (three [10%] patients). Other grade 3 or worse adverse events occurring during BAT in one [3%] patient each were pulmonary embolism, myocardial infarction, urinary obstruction, gallstone, and sepsis. During enzalutamide retreatment, no grade 3-4 toxicities occurred in more than one patient. No treatment-related deaths were reported during either BAT or enzalutamide retreatment.

INTERPRETATION

BAT is a safe therapy that resulted in responses in asymptomatic men with metastatic castration-resistant prostate cancer and also resensitisation to enzalutamide in most patients undergoing rechallenge. Further studies with BAT are needed to define the potential clinical role for BAT in the management of metastatic castration-resistant prostate cancer and the optimal strategy for sequencing between androgen and antiandrogen therapies in metastatic castration-resistant prostate cancer to maximise therapeutic benefit to patients.

FUNDING

National Institutes of Health and National Cancer Institute.