Punctuated evolution of prostate cancer genomes.

The analysis of exonic DNA from prostate cancers has identified recurrently mutated genes, but the spectrum of genome-wide alterations has not been profiled extensively in this disease. We sequenced the genomes of 57 prostate tumors and matched normal tissues to characterize somatic alterations and to study how they accumulate during oncogenesis and progression. By modeling the genesis of genomic rearrangements, we identified abundant DNA translocations and deletions that arise in a highly interdependent manner. This phenomenon, which we term "chromoplexy," frequently accounts for the dysregulation of prostate cancer genes and appears to disrupt multiple cancer genes coordinately. Our modeling suggests that chromoplexy may induce considerable genomic derangement over relatively few events in prostate cancer and other neoplasms, supporting a model of punctuated cancer evolution. By characterizing the clonal hierarchy of genomic lesions in prostate tumors, we charted a path of oncogenic events along which chromoplexy may drive prostate carcinogenesis.

ArCH: improving the performance of clonal hematopoiesis variant calling and interpretation.

MOTIVATION: The acquisition of somatic mutations in hematopoietic stem and progenitor stem cells with resultant clonal expansion, termed clonal hematopoiesis (CH), is associated with increased risk of hematologic malignancies and other adverse outcomes. CH is generally present at low allelic fractions, but clonal expansion and acquisition of additional mutations leads to hematologic cancers in a small proportion of individuals. With high depth and high sensitivity sequencing, CH can be detected in most adults and its clonal trajectory mapped over time. However, accurate CH variant calling is challenging due to the difficulty in distinguishing low frequency CH mutations from sequencing artifacts. The lack of well-validated bioinformatic pipelines for CH calling may contribute to lack of reproducibility in studies of CH. RESULTS: Here, we developed ArCH, an Artifact filtering Clonal Hematopoiesis variant calling pipeline for detecting single nucleotide variants and short insertions/deletions by combining the output of four variant calling tools and filtering based on variant characteristics and sequencing error rate estimation. ArCH is an end-to-end cloud-based pipeline optimized to accept a variety of inputs with customizable parameters adaptable to multiple sequencing technologies, research questions, and datasets. Using deep targeted sequencing data generated from six acute myeloid leukemia patient tumor: normal dilutions, 31 blood samples with orthogonal validation, and 26 blood samples with technical replicates, we show that ArCH improves the sensitivity and positive predictive value of CH variant detection at low allele frequencies compared to standard application of commonly used variant calling approaches. AVAILABILITY AND IMPLEMENTATION: The code for this workflow is available at: https://github.com/kbolton-lab/ArCH.

Inhibition of EZH2 transactivation function sensitizes solid tumors to genotoxic stress.

Drugs that block the activity of the methyltransferase EZH2 are in clinical development for the treatment of non-Hodgkin lymphomas harboring EZH2 gain-of-function mutations that enhance its polycomb repressive function. We have previously reported that EZH2 can act as a transcriptional activator in castration-resistant prostate cancer (CRPC). Now we show that EZH2 inhibitors can also block the transactivation activity of EZH2 and inhibit the growth of CRPC cells. Gene expression and epigenomics profiling of cells treated with EZH2 inhibitors demonstrated that in addition to derepressing gene expression, these compounds also robustly down-regulate a set of DNA damage repair (DDR) genes, especially those involved in the base excision repair (BER) pathway. Methylation of the pioneer factor FOXA1 by EZH2 contributes to the activation of these genes, and interaction with the transcriptional coactivator P300 via the transactivation domain on EZH2 directly turns on the transcription. In addition, CRISPR-Cas9-mediated knockout screens in the presence of EZH2 inhibitors identified these BER genes as the determinants that underlie the growth-inhibitory effect of EZH2 inhibitors. Interrogation of public data from diverse types of solid tumors expressing wild-type EZH2 demonstrated that expression of DDR genes is significantly correlated with EZH2 dependency and cellular sensitivity to EZH2 inhibitors. Consistent with these findings, treatment of CRPC cells with EZH2 inhibitors dramatically enhances their sensitivity to genotoxic stress. These studies reveal a previously unappreciated mechanism of action of EZH2 inhibitors and provide a mechanistic basis for potential combination cancer therapies.

SLCO1B3 and SLCO2B1 genotypes, androgen deprivation therapy, and prostate cancer outcomes: a prospective cohort study and meta-analysis.

Solute carrier organic anion (SLCO) transporters (OATP transporters) are involved in cellular uptake of drugs and hormones. Germline variants in SLCO1B3 and SLCO2B1 have been implicated in prostate cancer progression and therapy response, including to androgen deprivation and statin medications, but results have appeared heterogeneous. We conducted a cohort study of five single-nucleotide polymorphisms (SNPs) in SLCO1B3 and SLCO2B1 with prior evidence among 3208 men with prostate cancer who participated in the Health Professionals Follow-up Study or the Physicians' Health Study, following participants prospectively after diagnosis over 32 years (median, 14 years) for development of metastases and cancer-specific death (lethal disease, 382 events). Results were suggestive of, but not conclusive for, associations between some SNPs and lethal disease and differences by androgen deprivation and statin use. All candidate SNPs were associated with SLCO mRNA expression in tumor-adjacent prostate tissue. We also conducted a systematic review and harmonized estimates for a dose-response meta-analysis of all available data, including 9 further studies, for a total of 5598 patients and 1473 clinical events. The A allele of the exonic SNP rs12422149 (14% prevalence), which leads to lower cellular testosterone precursor uptake via SLCO2B1, was associated with lower rates of prostate cancer progression (hazard ratio per A allele, 0.80; 95% confidence interval, 0.69-0.93), with little heterogeneity between studies (I2, 0.27). Collectively, the totality of evidence suggests a strong association between inherited genetic variation in SLCO2B1 and prostate cancer prognosis, with potential clinical use in risk stratification related to androgen deprivation therapy.

Development and Optimization of a Subtraction-Normalized Immunocyte Profiling Signature for Prostate Cancer Active Surveillance Risk Stratification.

PURPOSE: Less invasive decision support tools are desperately needed to identify occult high-risk disease in men with prostate cancer (PCa) on active surveillance (AS). For a variety of reasons, many men on AS with low- or intermediate-risk disease forgo the necessary repeat surveillance biopsies needed to identify potentially higher-risk PCa. Here, we describe the development of a blood-based immunocyte transcriptomic signature to identify men harboring occult aggressive PCa. We then validate it on a biopsy-positive population with the goal of identifying men who should not be on AS and confirm those men with indolent disease who can safely remain on AS. This model uses subtraction-normalized immunocyte transcriptomic profiles to risk-stratify men with PCa who could be candidates for AS. MATERIALS AND METHODS: Men were eligible for enrollment in the study if they were determined by their physician to have a risk profile that warranted prostate biopsy. Both training (n = 1017) and validation cohort (n = 1198) populations had blood samples drawn coincident to their prostate biopsy. Purified CD2+ and CD14+ immune cells were obtained from peripheral blood mononuclear cells, and RNA was extracted and sequenced. To avoid overfitting and unnecessary complexity, a regularized regression model was built on the training cohort to predict PCa aggressiveness based on the National Comprehensive Cancer Network PCa guidelines. This model was then validated on an independent cohort of biopsy-positive men only, using National Comprehensive Cancer Network unfavorable intermediate risk and worse as an aggressiveness outcome, identifying patients who were not appropriate for AS. RESULTS: The best final model for the AS setting was obtained by combining an immunocyte transcriptomic profile based on 2 cell types with PSA density and age, reaching an AUC of 0.73 (95% CI: 0.69-0.77). The model significantly outperforms (P < .001) PSA density as a biomarker, which has an AUC of 0.69 (95% CI: 0.65-0.73). This model yields an individualized patient risk score with 90% negative predictive value and 50% positive predictive value. CONCLUSIONS: While further validation in an intended-use cohort is needed, the immunocyte transcriptomic model offers a promising tool for risk stratification of individual patients who are being considered for AS.

Androgen receptor regulates a distinct transcription program in androgen-independent prostate cancer.

The evolution of prostate cancer from an androgen-dependent state to one that is androgen-independent marks its lethal progression. The androgen receptor (AR) is essential in both, though its function in androgen-independent cancers is poorly understood. We have defined the direct AR-dependent target genes in both androgen-dependent and -independent cancer cells by generating AR-dependent gene expression profiles and AR cistromes. In contrast to what is found in androgen-dependent cells, AR selectively upregulates M-phase cell-cycle genes in androgen-independent cells, including UBE2C, a gene that inactivates the M-phase checkpoint. We find that epigenetic marks at the UBE2C enhancer, notably histone H3K4 methylation and FoxA1 transcription factor binding, are present in androgen-independent cells and direct AR-enhancer binding and UBE2C activation. Thus, the role of AR in androgen-independent cancer cells is not to direct the androgen-dependent gene expression program without androgen, but rather to execute a distinct program resulting in androgen-independent growth.

Experience with the US health care system for Black and White patients with advanced prostate cancer.

OBJECTIVE: The purpose of this study was to assess differences in reported information about treatment, integration into care, and respect by self-identified Black and White individuals with advanced prostate cancer in the United States. PATIENTS AND METHODS: This is a prospective cohort study of 701 participants (20% identifying as Black) enrolled in the International Registry for Men with Advanced Prostate Cancer at 37 US sites from 2017 to 2022. Participants were asked six questions from the Cancer Australia National Cancer Control Indicators about their experience with care at study enrollment. Prevalence differences by self-reported race were estimated using marginal standardization of logistic-normal mixed effects models (adjusted for age at enrollment and disease state at enrollment), and 95% CIs were estimated using parametric bootstrapping. RESULTS: Most participants reported a high quality of care for each question. Black participants generally reported higher care quality compared with White participants. Black participants reported more frequently that they were offered a written assessment and care plan (71%) compared with White participants (58%; adjusted difference, 13 percentage points; 95% CI, 4-23). Black participants also reported more frequently being given the name of nonphysician personnel who would support them (64%) than White participants (52%; adjusted difference, 10; 95% CI, 1-20). Prevalence differences did not differ by disease state at enrollment. CONCLUSIONS: Black participants generally reported a higher quality of care compared with White participants. This study calls attention to the need to study potential mediating factors and interpersonal aspects of care in this population to improve survivorship.

Quality of life in the year after new diagnosis with advanced prostate cancer for Black and White individuals living in the US.

PURPOSE: To assess differences in baseline and longitudinal quality of life among Black and White individuals in the US with advanced prostate cancer. METHODS: Secondary analysis of data from the International Registry for Men with Advanced Prostate Cancer (IRONMAN) including US participants newly diagnosed with advanced prostate cancer and identifying their race as Black or White from 2017 to 2023. Participants completed the EORTC QLQ-C30 Quality of Life (QoL) Survey at study enrollment and every 3 months thereafter for up to 1 year of follow-up reporting 15 scale scores ranging from 0 to 100 (higher functioning and lower symptom scores represent better quality of life). Linear mixed effects models with race and month of questionnaire completion were fit for each scale, and model coefficients were used to assess differences in baseline and longitudinal QoL by race. RESULTS: Eight hundred and seventy-nine participants were included (20% identifying as Black) at 38 US sites. Compared to White participants at baseline, Black participants had worse constipation (mean 6.3 percentage points higher; 95% CI 2.9-9.8), financial insecurity (5.7 (1.4-10.0)), and pain (5.1 (0.9-9.3)). QoL decreased over time similarly by race; most notably, role functioning decreased by 0.7 percentage points (95% CI -0.8, -0.5) per month. CONCLUSION: There are notable differences in quality of life at new diagnosis of advanced prostate cancer for Black and White individuals, and quality of life declines similarly in the first year for both groups. Interventions that address specific aspects of quality of life in these patients could meaningfully improve the overall survivorship experience.

Clinical annotations for prostate cancer research: Defining data elements, creating a reproducible analytical pipeline, and assessing data quality.

BACKGROUND: Routine clinical data from clinical charts are indispensable for retrospective and prospective observational studies and clinical trials. Their reproducibility is often not assessed. We developed a prostate cancer-specific database for clinical annotations and evaluated data reproducibility. METHODS: For men with prostate cancer who had clinical-grade paired tumor-normal sequencing at a comprehensive cancer center, we performed team-based retrospective data collection from the electronic medical record using a defined source hierarchy. We developed an open-source R package for data processing. With blinded repeat annotation by a reference medical oncologist, we assessed data completeness, reproducibility of team-based annotations, and impact of measurement error on bias in survival analyses. RESULTS: Data elements on demographics, diagnosis and staging, disease state at the time of procuring a genomically characterized sample, and clinical outcomes were piloted and then abstracted for 2261 patients (with 2631 samples). Completeness of data elements was generally high. Comparing to the repeat annotation by a medical oncologist blinded to the database (100 patients/samples), reproducibility of annotations was high; T stage, metastasis date, and presence and date of castration resistance had lower reproducibility. Impact of measurement error on estimates for strong prognostic factors was modest. CONCLUSIONS: With a prostate cancer-specific data dictionary and quality control measures, manual clinical annotations by a multidisciplinary team can be scalable and reproducible. The data dictionary and the R package for reproducible data processing are freely available to increase data quality and efficiency in clinical prostate cancer research.

Aneuploidy drives lethal progression in prostate cancer.

Aneuploidy, defined as chromosome gains and losses, is a hallmark of cancer. However, compared with other tumor types, extensive aneuploidy is relatively rare in prostate cancer. Thus, whether numerical chromosome aberrations dictate disease progression in prostate cancer patients is not known. Here, we report the development of a method based on whole-transcriptome profiling that allowed us to identify chromosome-arm gains and losses in 333 primary prostate tumors. In two independent cohorts (n = 404) followed prospectively for metastases and prostate cancer-specific death for a median of 15 years, increasing extent of tumor aneuploidy as predicted from the tumor transcriptome was strongly associated with higher risk of lethal disease. The 23% of patients whose tumors had five or more predicted chromosome-arm alterations had 5.3 times higher odds of lethal cancer (95% confidence interval, 2.2 to 13.1) than those with the same Gleason score and no predicted aneuploidy. Aneuploidy was associated with lethality even among men with high-risk Gleason score 8-to-10 tumors. These results point to a key role of aneuploidy in driving aggressive disease in primary prostate cancer.

Genomic correlates of clinical outcome in advanced prostate cancer.

Heterogeneity in the genomic landscape of metastatic prostate cancer has become apparent through several comprehensive profiling efforts, but little is known about the impact of this heterogeneity on clinical outcome. Here, we report comprehensive genomic and transcriptomic analysis of 429 patients with metastatic castration-resistant prostate cancer (mCRPC) linked with longitudinal clinical outcomes, integrating findings from whole-exome, transcriptome, and histologic analysis. For 128 patients treated with a first-line next-generation androgen receptor signaling inhibitor (ARSI; abiraterone or enzalutamide), we examined the association of 18 recurrent DNA- and RNA-based genomic alterations, including androgen receptor (AR) variant expression, AR transcriptional output, and neuroendocrine expression signatures, with clinical outcomes. Of these, only RB1 alteration was significantly associated with poor survival, whereas alterations in RB1, AR, and TP53 were associated with shorter time on treatment with an ARSI. This large analysis integrating mCRPC genomics with histology and clinical outcomes identifies RB1 genomic alteration as a potent predictor of poor outcome, and is a community resource for further interrogation of clinical and molecular associations.

Prostate-specific antigen nadir and testosterone level at prostate-specific antigen failure following radiation and androgen suppression therapy for unfavorable-risk prostate cancer and the risk of all-cause and prostate cancer-specific mortality.

BACKGROUND: Although both PSA nadir (PSAn) and testosterone levels at PSA failure are known prognostic factors in men undergoing radiation therapy (RT) and androgen deprivation therapy (ADT) for unfavorable-risk prostate cancer (PC), it is unclear whether their prognostic significance is independent or overlapping. METHODS: Seventy-five men treated with RT with or without 6 months of ADT for unfavorable-risk nonmetastatic PC enrolled in 2 prospective clinical trials between 1986 and 2001 formed the study cohort. Competing risks and Cox multivariable regression were used to assess whether low versus normal serum testosterone at the time of PSA failure and higher PSAn after initial therapy were independently associated with the risk of PC-specific (PCSM) and all-cause mortality (ACM) adjusting for PC prognostic factors. RESULTS: After a median follow-up of 15.34 years (interquartile range, 6.66-16.88 years), there were 53 deaths (73.3%): 30 (56.6%) were from PC. Low testosterone at PSA failure was significantly associated with an increased risk of PCSM (adjusted HR [AHR], 7.77; 95% CI, 1.14-52.99; P = .04) and ACM (AHR, 3.01; 95% CI, 1.01-8.96; P = .05), as was higher PSAn (PCSM AHR, 1.03; 95% CI, 1.01-1.05; P < .01; ACM AHR, 1.04; 95% CI, 1.02-1.07; P < .01), although the prognostic significance of PSAn was only noted in men with a normal testosterone at PSA failure. CONCLUSIONS: Low testosterone level at PSA failure in high-risk patients with PC treated with RT is associated with increased PCSM and ACM risk. In men with normal testosterone levels at the time of PSA failure, an elevated PSAn was associated with worse PCSM and ACM risk. LAY SUMMARY: This study investigates whether the prostate-specific antigen (PSA) nadir and normal versus low testosterone at the time of PSA failure provide mutually exclusive or overlapping prognostic information following treatment with radiation and androgen deprivation therapy for unfavorable-risk patients with prostate cancer using data from 2 prospective clinical trials. It was found that both provided prognostic information; however, higher PSA nadir was only found to be of prognostic significance in men with normal testosterone levels at PSA failure.

Treatment of Advanced Prostate Cancer.

The therapeutic landscape of prostate cancer has been transformed over the last decade by new therapeutics, advanced functional imaging, next-generation sequencing, and better use of existing therapies in early-stage disease. Until 2004, progression on androgen deprivation therapy for metastatic disease was treated with the addition of secondary hormonal manipulation; in the last decade, six systemic agents have been approved for the treatment of castration-resistant prostate cancer. We review clinical trials and survival benefit for these therapies and assess how the understanding of the disease shifted as these therapies were developed. We also discuss advances in noncastrate disease states, identification of biomarkers for prognosis and treatment selection, and opportunities in locoregional therapy to delay androgen deprivation therapy.

Tumor protein expression of the DNA repair gene BRCA1 and lethal prostate cancer.

DNA repair genes are commonly altered in metastatic prostate cancer, but BRCA1 mutations are rare. Preliminary studies suggest that higher tumor expression of the BRCA1 protein may be associated with worse prognosis. We undertook a prospective study among men with prostate cancer in the Health Professionals Follow-up Study and evaluated BRCA1 via immunohistochemical staining on tissue microarrays. BRCA1 was expressed in 60 of 589 tumors. Prevalence of BRCA1 positivity was 43% in the 14 men with metastases at diagnosis compared with 9% in non-metastatic tumors [difference, 33 percentage points; 95% confidence interval (CI), 7-59]. BRCA1-positive tumors had 2.16-fold higher Ki-67 proliferative indices (95% CI, 1.18-3.95), higher tumor aneuploidy as predicted from whole-transcriptome profiling, and higher Gleason scores. Among the 575 patients with non-metastatic disease at diagnosis, we evaluated the association between BRCA1 expression and development of lethal disease (metastasis or cancer-specific death, 69 events) during long-term follow-up (median, 18.3 years). A potential weak association of BRCA1 positivity with lethal disease (hazard ratio, 1.61; 95% CI, 0.82-3.15) was attenuated when adjusting for age, Gleason score and clinical stage (hazard ratio, 1.11; 95% CI, 0.54-2.29). In summary, BRCA1 protein expression is a feature of more proliferative and more aneuploid prostate tumors and is more common in metastatic disease. While not well suited as a prognostic biomarker in primary prostate cancer, BRCA1 protein expression may be most relevant in advanced disease.

Family history of prostate cancer and the incidence of ERG- and phosphatase and tensin homolog-defined prostate cancer.

Family history is among the strongest known risk factors for prostate cancer (PCa). Emerging data suggest molecular subtypes of PCa, including two somatic genetic aberrations: fusions of androgen-regulated promoters with ERG and, separately, phosphatase and tensin homolog (PTEN) loss. We examined associations between family history and incidence of these subtypes in 44,126 men from the prospective Health Professionals Follow-up Study. ERG and PTEN status were assessed by immunohistochemistry. Multivariable competing risks models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for associations between self-reported family history of PCa and molecular subtypes of disease. Thirteen percent of men had a positive family history of PCa at baseline. During a median follow-up of 18.5 years, 5,511 PCa cases were diagnosed. Among them, 888 were assayed for ERG status (47% ERG-positive) and 715 were assayed for PTEN loss (14% PTEN null). Family history was more strongly associated with risk of ERG-negative (HR: 2.15; 95% CI: 1.71-2.70) than ERG-positive (HR: 1.49; 95% CI: 1.13-1.95) disease (pheterogeneity : 0.04). The strongest difference was among men with an affected father (HRERG-negative : 2.09; 95% CI: 1.64-2.66; HRERG-positive : 1.30; 95% CI: 0.96-1.76; pheterogeneity : 0.01). Family history of PCa was positively associated with both PTEN null (HR: 2.10; 95% CI: 1.26-3.49) and PTEN intact (HR: 1.72; 95% CI: 1.39-2.13) PCa (pheterogeneity : 0.47). Our results indicate that PCa family history may be positively associated with PCa in all ERG and PTEN subtypes, suggesting a role of genetic susceptibility in their development. It is possible that ERG-negative disease could be especially associated with positive family history.

Effects of acupuncture versus cognitive behavioral therapy on cognitive function in cancer survivors with insomnia: A secondary analysis of a randomized clinical trial.

BACKGROUND: Cancer-related cognitive impairment is a prevalent, disruptive condition potentially exacerbated by sleep disturbances. The current study was performed to evaluate the effects of acupuncture versus cognitive behavioral therapy for insomnia (CBT-I) on objective and subjective cognitive function in cancer survivors with insomnia. METHODS: Using data from a randomized clinical trial (160 survivors) that compared acupuncture versus CBT-I for insomnia occurring in cancer survivors, the authors analyzed cognitive outcomes and their relationship to insomnia symptoms. Analysis was limited to 99 patients who reported baseline cognitive difficulties. Interventions were delivered over 8 weeks. Objective attention, learning, and memory were evaluated using the Buschke Selective Reminding Test. Subjective cognitive function was assessed using the Brown Attention-Deficit Disorder Scales. Insomnia symptoms were assessed using the Insomnia Severity Index. All outcomes were collected at baseline, week 8, and week 20. RESULTS: From baseline to week 8, acupuncture produced statistically significant within-group improvements in objective attention (Cohen D, 0.29), learning (Cohen D, 0.31), and memory (Cohen D, 0.33) that persisted to week 20 (all P < .05), whereas CBT-I produced a statistically significant within-group improvement in objective attention from baseline to week 20 (Cohen D, 0.50; P < .05); between-group differences were not statistically significant. Both interventions produced statistically significant within-group improvements in subjective cognitive function at weeks 8 and 20 compared with baseline (all P < .001); between-group differences were not statistically significant. In the acupuncture group, patients with clinically meaningful responses with regard to insomnia symptoms demonstrated a significantly greater improvement in subjective cognitive function compared with those without clinically meaningful insomnia responses (P = .006). CONCLUSIONS: Among cancer survivors with insomnia, both acupuncture and CBT-I produced significant improvements in objective and subjective cognitive function. However, the effect sizes varied and only survivors in the acupuncture group demonstrated a significant relationship between cognitive and sleep outcomes. These preliminary findings warrant further investigation to guide the personalized management of patients with cancer-related cognitive impairment.

Association of genetic variation of the six gene prognostic model for castration-resistant prostate cancer with survival.

BACKGROUND: We previously identified a blood RNA transcript-based model consisting of six immune or inflammatory response genes (ABL2, SEMA4D, ITGAL, C1QA, TIMP1, and CDKN1A) that was prognostic for survival in cohorts of men with castration-resistant prostate cancer (CRPC). We investigated whether inherited variation in these six genes was associated with overall survival (OS) in men with CRPC. METHODS: The test cohort comprised 600 patients diagnosed with CRPC between 1996 and 2011 at Dana-Farber Cancer Institute. Genotyping of 66 tagging single nucleotide polymorphisms (SNPs) spanning the six genes was performed on blood derived DNAs. For the top four SNPs (P < 0.05), validation was conducted in an independent cohort of 223 men diagnosed with CRPC between 2000 and 2014. Multivariable Cox regression adjusting for known prognostic factors estimated hazard ratios (HR) and 95% confidence intervals (CI) of the association of genetic variants with OS. RESULTS: Two thirds of patients in both cohorts had metastases at CRPC diagnosis. Median OS from CRPC diagnosis was 3.6 (95%CI 3.3-4.0) years in the test cohort and 4.6 (95%CI 3.8-5.2) years in the validation cohort. Fifty-nine SNPs in Hardy-Weinberg equilibrium were analyzed. The major alleles of rs1318056 and rs1490311 in ABL2, and the minor alleles of rs2073917 and rs3764322 in ITGAL were associated with increased risk of death in the test cohort (adjusted-HRs 1.27-1.39; adjusted-p <0.05; false discovery rate <0.35). In the validation cohort, a similar association with OS was observed for rs1318056 in ABL2 (adjusted-HR 1.44; 95%CI 0.89-2.34) and rs2073917 in ITGAL (adjusted-HR 1.41; 95%CI 0.82-2.42). The associations did not reach statistical significance most likely due to the small sample size of the validation cohort (adjusted-p = 0.142 and 0.209, respectively). Additional eQTL analysis indicated that minor alleles of rs1318056 and rs1490311 in ABL2 are associated with a lower ABL2 expression in blood. CONCLUSIONS: These findings corroborate our initial work on the RNA expression of genes involved in immunity and inflammation from blood and clinical outcome and suggest that germline polymorphisms in ABL2 and ITGAL may be associated with the risk of death in men with CRPC. Further studies are needed to validate these findings and to explore their functional mechanisms.

Phase 1 study of PSMA ADC, an antibody-drug conjugate targeting prostate-specific membrane antigen, in chemotherapy-refractory prostate cancer.

BACKGROUND: Prostate-specific membrane antigen (PSMA) is a well-characterized target that is overexpressed selectively on prostate cancer cells. PSMA antibody-drug conjugate (ADC) is a fully human IgG1 monoclonal antibody conjugated to the microtubule disrupting agent monomethyl auristatin E (MMAE), which is designed to specifically bind PSMA-positive cells, internalize, and then release its cytotoxic payload into the cells. PSMA ADC has demonstrated potent and selective antitumor activity in preclinical models of advanced prostate cancer. A Phase 1 study was conducted to assess the safety, pharmacokinetics, and preliminary antitumor effects of PSMA ADC in subjects with treatment-refractory prostate cancer. METHODS: In this first-in-man dose-escalation study, PSMA ADC was administered by intravenous infusion every three weeks to subjects with progressive metastatic castration-resistant prostate cancer (mCRPC) who were previously treated with docetaxel chemotherapy. The primary endpoint was to establish a maximum tolerated dose (MTD). The study also examined the pharmacokinetics of the study drug, total antibody, and free MMAE. Antitumor effects were assessed by measuring changes in serum prostate-specific antigen (PSA), circulating tumor cells (CTCs), and radiologic imaging. RESULTS: Fifty-two subjects were administered doses ranging from 0.4 to 2.8 mg/kg. Subjects had a median of two prior chemotherapy regimens and prior treatment with abiraterone and/or enzalutamide. Neutropenia and peripheral neuropathy were identified as important first-cycle and late dose-limiting toxicities, respectively. The dose of 2.5 mg/kg was determined to be the MTD. Pharmacokinetics were approximately dose-proportional with minimal drug accumulation. Reductions in PSA and CTCs in subjects treated with doses of ≥1.8 mg/kg were durable and often concurrent. CONCLUSIONS: In an extensively pretreated mCRPC population, PSMA ADC demonstrated acceptable toxicity. Antitumor activity was observed over dose ranges up to and including 2.5 mg/kg. The observed anti-tumor activity supported further evaluation of this novel agent for the treatment of advanced metastatic prostate cancer.

A phase 2 trial of abiraterone acetate without glucocorticoids for men with metastatic castration-resistant prostate cancer.

BACKGROUND: Abiraterone acetate suppresses adrenal androgens and glucocorticoids through the inhibition of CYP17; however, given the risk of mineralocorticoid excess, it is administered with glucocorticoids. Herein, the authors performed a phase 2, single-arm study that was designed to assess the safety of abiraterone acetate without steroids in patients with castration-resistant prostate cancer. METHODS: Eligible patients had castration-resistant prostate cancer with controlled blood pressure and normal potassium. Patients initially received abiraterone acetate at a dose of 1000 mg daily alone. Those with persistent or severe mineralocorticoid toxicity received treatment with prednisone initiated at a dose of 5 mg twice daily. Therapy was continued until radiographic progression, toxicity, or withdrawal. The primary objective of the current study was to determine the percentage of men requiring prednisone to manage mineralocorticoid toxicity. Toxicity was graded according to Common Terminology Criteria for Adverse Events, version 4.0. RESULTS: A total of 58 patients received at least 1 dose of abiraterone acetate; the majority had metastases (53 patients; 91.4%). Sixteen patients (27.6%) received prior chemotherapy, 6 patients (10.3%) received prior enzalutamide, and 4 patients (7%) received prior ketoconazole. Grade 3 to 4 adverse events of interest included hypertension (9 patients; 15.5%) and hypokalemia (4 patients; 7%). There was no grade ≥3 edema. Seven patients (12%) initiated prednisone therapy for mineralocorticoid toxicity, 3 patients for hypertension (5%), and 4 patients for hypokalemia (7%). Two patients initiated prednisone therapy for fatigue (3%). Forty patients (68%) experienced a decline in prostate-specific antigen of ≥50% with the use of abiraterone acetate alone. Patients with lower baseline levels of androstenedione (P = .04), androsterone (P = .01), dehydroepiandrosterone (P = .03), and 17-hydroxyprogesterone (P = .03) were found to be more likely to develop mineralocorticoid toxicity. CONCLUSIONS: Treatment with abiraterone acetate without steroids is feasible, although clinically significant adverse events can occur in a minority of patients. The use of abiraterone acetate without prednisone should be balanced with the potential for toxicity and requires close monitoring.

Real-world outcomes of sipuleucel-T treatment in PROCEED, a prospective registry of men with metastatic castration-resistant prostate cancer.

BACKGROUND: The large registry, PROVENGE Registry for the Observation, Collection, and Evaluation of Experience Data (PROCEED)(NCT01306890), evaluated sipuleucel-T immunotherapy for asymptomatic/minimally symptomatic metastatic castration-resistant prostate cancer (mCRPC). METHODS: PROCEED enrolled patients with mCRPC receiving 3 biweekly sipuleucel-T infusions. Assessments included overall survival (OS), serious adverse events (SAEs), cerebrovascular events (CVEs), and anticancer interventions (ACIs). Follow-up was for ≥3 years or until death or study withdrawal. RESULTS: In 2011-2017, 1976 patients were followed for 46.6 months (median). The median age was 72 years, and the baseline median prostate-specific antigen level was 15.0 ng/mL; 86.7% were white, and 11.6% were African American. Among the patients, 1902 had 1 or more sipuleucel-T infusions. The median OS was 30.7 months (95% confidence interval [CI], 28.6-32.2 months). Known prognostic factors were independently associated with OS in a multivariable analysis. Among the 1255 patients who died, 964 (76.8%) died of prostate cancer (PC) progression. The median time from the first infusion to PC death was 42.7 months (95% CI, 39.4-46.2 months). The incidence of sipuleucel-T-related SAEs was 3.9%. The incidence of CVEs was 2.8%, and the rate per 100 person-years was 1.2 (95% CI, 0.9-1.6). The CVE incidence among 11,972 patients with mCRPC from the Surveillance, Epidemiology, and End Results-Medicare database was 2.8%; the rate per 100 person-years was 1.5 (95% CI, 1.4-1.7). One or more ACIs (abiraterone, enzalutamide, docetaxel, cabazitaxel, or radium 223) were received by 77.1% of the patients after sipuleucel-T; 32.5% and 17.4% of the patients experienced 1- and 2-year treatment-free intervals, respectively. CONCLUSIONS: PROCEED provides contemporary survival data for sipuleucel-T-treated men in a real-world setting of new life-prolonging agents, which will be useful in discussing treatment options with patients and in powering future trials with sipuleucel-T. The safety and tolerability of sipuleucel-T in PROCEED were consistent with previous findings.