The gut microbiome-prostate cancer crosstalk is modulated by dietary polyunsaturated long-chain fatty acids

The gut microbiota modulates response to hormonal treatments in prostate cancer (PCa) patients, but whether it influences PCa progression remains unknown. Here, we show a reduction in fecal microbiota alpha-diversity correlating with increase tumour burden in two distinct groups of hormonotherapy naïve PCa patients and three murine PCa models. Fecal microbiota transplantation (FMT) from patients with high PCa volume is sufficient to stimulate the growth of mouse PCa revealing the existence of a gut microbiome-cancer crosstalk. Analysis of gut microbial-related pathways in mice with aggressive PCa identifies three enzymes responsible for the metabolism of long-chain fatty acids (LCFA). Supplementation with LCFA omega-3 MAG-EPA is sufficient to reduce PCa growth in mice and cancer up-grading in pre-prostatectomy PCa patients correlating with a reduction of gut Ruminococcaceae in both and fecal butyrate levels in PCa patients. This suggests that the beneficial effect of omega-3 rich diet is mediated in part by modulating the crosstalk between gut microbes and their metabolites in men with PCa.

The estrogen signaling pathway reprograms prostate cancer cell metabolism and supports proliferation and disease progression

Just as the androgen receptor (AR), the estrogen receptor α (ERα) is expressed in the prostate and is thought to influence prostate cancer (PCa) biology. Yet, the incomplete understanding of ERα functions in PCa hinders our ability to fully comprehend its clinical relevance and restricts the repurposing of estrogen-targeted therapies for the treatment of this disease. Using two human PCa tissue microarray cohorts, we first demonstrated that nuclear ERα expression was heterogeneous among patients, being only detected in half of tumors. Positive nuclear ERα levels were correlated with disease recurrence, progression to metastatic PCa, and patient survival. Using in vitro and in vivo models of the normal prostate and PCa, bulk and single-cell RNA-Seq analyses revealed that estrogens partially mimic the androgen transcriptional response and induce specific biological pathways linked to proliferation and metabolism. Bioenergetic flux assays and metabolomics confirmed the regulation of cancer metabolism by estrogens, supporting proliferation. Using cancer cell lines and patient-derived organoids, selective estrogen receptor modulators, a pure anti-estrogen, and genetic approaches impaired cancer cell proliferation and growth in an ERα-dependent manner. Overall, our study revealed that, when expressed, ERα functionally reprograms PCa metabolism, is associated with disease progression, and could be targeted for therapeutic purposes.

A phase IIb randomized placebo-controlled trial testing the effect of MAG-EPA long-chain omega-3 fatty acid dietary supplement on prostate cancer proliferation

BACKGROUND

High prostate eicosapentaenoic fatty acid (EPA) levels were associated with a significant reduction of upgrading to grade group (GG) ≥ 2 prostate cancer in men under active surveillance. We aimed to evaluate the effect of MAG-EPA long-chain omega-3 fatty acid dietary supplement on prostate cancer proliferation.

METHODS

A phase II double-blind randomized placebo-controlled trial was conducted in 130 men diagnosed with GG ≥ 2 prostate cancer and undergoing radical prostatectomy between 2015-2017 (Clinicaltrials.gov: NCT02333435). Participants were randomized to receive 3 g daily of either MAG-EPA (n = 65) or placebo (n = 65) for 7 weeks (range 4-10) prior to radical prostatectomy. The primary outcome was the cancer proliferation index quantified by automated image analysis of tumor nuclear Ki-67 expression using standardized prostatectomy tissue microarrays. Additional planned outcomes at surgery are reported including plasma levels of 27 inflammatory cytokines and fatty acid profiles in circulating red blood cells membranes and prostate tissue.

RESULTS

Cancer proliferation index measured by Ki-67 expression was not statistically different between the intervention (3.10%) and placebo (2.85%) groups (p = 0.64). In the per protocol analyses, the adjusted estimated effect of MAG-EPA was greater but remained non-significant. Secondary outcome was the changes in plasma levels of 27 cytokines, of which only IL-7 was higher in MAG-EPA group compared to placebo (p = 0.026). Men randomized to MAG-EPA prior to surgery had four-fold higher EPA levels in prostate tissue compared to those on placebo.

CONCLUSIONS

This MAG-EPA intervention did not affect the primary outcome of prostate cancer proliferation according to nuclear Ki-67 expression. More studies are needed to decipher the effects of long-chain omega-3 fatty acid dietary supplementation in men with prostate cancer.

Salvage therapy for BCG failure with intravesical sequential gemcitabine and docetaxel in patients with recurrent NMIBC

INTRODUCTION

Bacillus Calmette-Guérin (BCG) failure occurs in approximately 40% of patients with non-muscle-invasive bladder cancer (NMIBC) within two years. We describe our institutional experience with sequential intravesical gemcitabine and docetaxel (gem/doce) as salvage therapy post-BCG failure in patients who were not candidates for or declined radical cystectomy (RC).

METHODS

We retrospectively reviewed NMIBC patients with BCG failure who received gem/doce from April 2019 through October 2022 at the CHU de Québec-Université Laval. Patients received at least five weekly intravesical instillations according to published protocols. Patients who responded to gem/doce had maintenance instillations monthly for up to two years. Primary outcome was progression-free survival (PFS). Secondary outcomes included recurrence-free survival (RFS), cystectomy-free survival (CFS), cancer-specific survival (CSS), overall survival (OS), and treatment adverse events. Survival probabilities were estimated using the Kaplan-Meier method from the first gem/doce instillation.

RESULTS

Thirty-five patients with a median age of 78 years old were included in the study. The median followup time was 21 months (interquartile range 10-29). More than 25% of patients received two or more prior BCG induction treatments. Overall and MIBC PFS estimates at one year were 85% and 88%, and at two years, 60% and 70%, respectively. Adverse events occurred in 37% of the patients, but only two patients didn't complete the treatment due to intolerance. Three patients underwent RC due to cancer progression. OS was 94% at two years.

CONCLUSIONS

With 60% of PFS at two years, gem/doce appears to be a safe and well-tolerated option for BCG failure patients. Further studies are needed to justify widespread use.

Effects of omega-3 supplementation on psychological symptoms in men with prostate cancer: Secondary analysis of a double-blind placebo-controlled randomized trial

BACKGROUND

In the general population, a higher omega-3 polyunsaturated fatty acids intake is associated with lower levels of several psychological symptoms, especially depression. However, the existing evidence in cancer is equivocal.

METHODS

This phase IIB double-blind, placebo-controlled trial was aimed at comparing the effects of eicosapentaenoic acid monoacylglyceride (MAG-EPA) supplementation and high oleic acid sunflower oil (HOSO; placebo) on depression levels (primary outcome) and other symptoms (anxiety, fear of cancer recurrence, fatigue, insomnia, perceived cognitive impairments; secondary outcomes). Participants, recruited in a prostate cancer clinic, were randomized to MAG-EPA (3.75 g daily; n = 65) or HOSO (3.75 g daily; n = 65) for 1 year post-radical prostatectomy (RP), starting 4-10 weeks before surgery. Patients completed self-report scales at baseline (before RP) and 3, 6, 9, and 12 months after: Hospital Anxiety and Depression Scale (HADS), Fear of Cancer Recurrence Inventory (FCRI), Insomnia Severity Index (ISI), Fatigue Symptom Inventory (FSI), and Functional Assessment of Cancer Therapy-Cognitive Function (FACT-Cog).

RESULTS

Analyses showed significant reductions in HADS-depression, HADS-anxiety, FCRI, ISI, FSI-number of days, and FACT-Cog-impact scores over time. A significant group-by-time interaction was obtained on FACT-Cog-Impact scores only; yet, the temporal change was significant in HOSO patients only.

CONCLUSIONS

Several symptoms significantly decreased over time, mainly within the first months of the study. However, MAG-EPA did not produce greater reductions than HOSO. Omega-3 supplementation does not seem to improve psychological symptoms of men treated with RP.

Isocitrate dehydrogenase 1 sustains a hybrid cytoplasmic-mitochondrial tricarboxylic acid cycle that can be targeted for therapeutic purposes in prostate cancer

The androgen receptor (AR) is an established orchestrator of cell metabolism in prostate cancer (PCa), notably by inducing an oxidative mitochondrial program. Intriguingly, AR regulates cytoplasmic isocitrate dehydrogenase 1 (IDH1), but not its mitochondrial counterparts IDH2 and IDH3. Here, we aimed to understand the functional role of IDH1 in PCa. Mouse models, in vitro human PCa cell lines, and human patient-derived organoids (PDOs) were used to study the expression and activity of IDH enzymes in the normal prostate and PCa. Genetic and pharmacological inhibition of IDH1 was then combined with extracellular flux analyses and gas chromatography-mass spectrometry for metabolomic analyses and cancer cell proliferation in vitro and in vivo. In PCa cells, more than 90% of the total IDH activity is mediated through IDH1 rather than its mitochondrial counterparts. This profile seems to originate from the specialized prostate metabolic program, as observed using mouse prostate and PDOs. Pharmacological and genetic inhibition of IDH1 impaired mitochondrial respiration, suggesting that this cytoplasmic enzyme contributes to the mitochondrial tricarboxylic acid cycle (TCA) in PCa. Mass spectrometry-based metabolomics confirmed this hypothesis, showing that inhibition of IDH1 impairs carbon flux into the TCA cycle. Consequently, inhibition of IDH1 decreased PCa cell proliferation in vitro and in vivo. These results demonstrate that PCa cells have a hybrid cytoplasmic-mitochondrial TCA cycle that depends on IDH1. This metabolic enzyme represents a metabolic vulnerability of PCa cells and a potential new therapeutic target.

High infiltration of CD209+ dendritic cells and CD163+ macrophages in the peritumor area of prostate cancer is predictive of late adverse outcomes

Introduction

Prostate cancer (PCa) shows considerable variation in clinical outcomes between individuals with similar diseases. The initial host-tumor interaction as assessed by detailed analysis of tumor infiltrating immune cells within the primary tumor may dictate tumor evolution and late clinical outcomes. In this study, we assessed the association between clinical outcomes and dendritic cell (DC) or macrophage (MΦ) tumor infiltration as well as with expression of genes related to their functions.

Methods

Infiltration and localization of immature DC, mature DC, total MΦ and M2-type MΦ was analyzed by immunohistochemistry in 99 radical prostatectomy specimens from patients with 15.5 years median clinical follow-up using antibodies against CD209, CD83, CD68 and CD163, respectively. The density of positive cells for each marker in various tumor areas was determined. In addition, expression of immune genes associated with DC and MΦ was tested in a series of 50 radical prostatectomy specimens by Taqman Low-Density Array with similarly long follow-up. Gene expression was classified as low and high after unsupervised hierarchical clustering. Numbers and ratio of positive cells and levels of gene expression were correlated with endpoints such as biochemical recurrence (BCR), need for definitive androgen deprivation therapy (ADT) or lethal PCa using Cox regression analyses and/or Kaplan-Meier curves.

Results

Positive immune cells were observed in tumor, tumor margin, and normal-like adjacent epithelium areas. CD209⁺ and CD163⁺ cells were more abundant at the tumor margin. Higher CD209⁺/CD83⁺ cell density ratio at the tumor margin was associated with higher risk of ADT and lethal PCa while higher density of CD163⁺ cells in the normal-like adjacent epithelium was associated with a higher risk of lethal PCa. A combination of 5 genes expressed at high levels correlated with a shorter survival without ADT and lethal PCa. Among these five genes, expression of IL12A and CD163 was correlated to each other and was associated with shorter survival without BCR and ADT/lethal PCa, respectively.

Conclusion

A higher level of infiltration of CD209⁺ immature DC and CD163⁺ M2-type MΦ in the peritumor area was associated with late adverse clinical outcomes.

Leukocytic Infiltration of Intraductal Carcinoma of the Prostate: An Exploratory Study

Intraductal carcinoma of the prostate (IDC-P) is an aggressive histological subtype of prostate cancer (PCa) detected in approximately 20% of radical prostatectomy (RP) specimens. As IDC-P has been associated with PCa-related death and poor responses to standard treatment, the purpose of this study was to explore the immune infiltrate of IDC-P. Hematoxylin- and eosin-stained slides from 96 patients with locally advanced PCa who underwent RP were reviewed to identify IDC-P. Immunohistochemical staining of CD3, CD8, CD45RO, FoxP3, CD68, CD163, CD209 and CD83 was performed. For each slide, the number of positive cells per mm² in the benign tissues, tumor margins, cancer and IDC-P was calculated. Consequently, IDC-P was found in a total of 33 patients (34%). Overall, the immune infiltrate was similar in the IDC-P-positive and the IDC-P-negative patients. However, FoxP3⁺ regulatory T cells (p < 0.001), CD68⁺ and CD163⁺ macrophages (p < 0.001 for both) and CD209⁺ and CD83⁺ dendritic cells (p = 0.002 and p = 0.013, respectively) were less abundant in the IDC-P tissues compared to the adjacent PCa. Moreover, the patients were classified as having immunologically "cold" or "hot" IDC-P, according to the immune-cell densities averaged in the total IDC-P or in the immune hotspots. The CD68/CD163/CD209-immune hotspots predicted metastatic dissemination (p = 0.014) and PCa-related death (p = 0.009) in a Kaplan-Meier survival analysis. Further studies on larger cohorts are necessary to evaluate the clinical utility of assessing the immune infiltrate of IDC-P with regards to patient prognosis and the use of immunotherapy for lethal PCa.

Abstract 3700: Isocitrate dehydrogenase 1 sustains a hybrid cytoplasmic-mitochondrial tricarboxylic acid cycle in prostate cancer

Background: The androgen receptor (AR) is an established orchestrator of cell metabolism in prostate cancer (PCa), notably by inducing an oxidative mitochondrial program. Intriguingly, AR regulates cytoplasmic isocitrate dehydrogenase 1 (IDH1) but not its mitochondrial counterparts IDH2 and IDH3. Here, we aimed to understand the functional role of IDH1 in PCa.

Methods: Mouse models, in vitro human PCa cell lines, and human prostate organoids were used to study the expression and activity of IDH enzymes in the normal prostate and PCa. Genetic and pharmacological inhibition of IDH1 was then combined with extracellular flux analysis and gas chromatography-mass spectrometry for metabolomic analyses and cancer cell proliferation in vitro and in vivo.

Results: In PCa cells, more than 90% of the total IDH activity is mediated through IDH1 rather than its mitochondrial counterparts. This profile seems to originate from the specialized prostate metabolic program, as observed using mouse prostate and human patient-derived organoids. Pharmacological and genetic inhibition of IDH1 impaired mitochondrial respiration, suggesting that this cytoplasmic enzyme contributes to the mitochondrial tricarboxylic acid cycle (TCA) in PCa. Mass spectrometry-based metabolomics confirmed this hypothesis, showing that inhibition of IDH1 impairs carbon flux into the TCA cycle. Consequently, inhibition of IDH1 decreased PCa cell proliferation in vitro and in vivo.

Conclusions: These results demonstrate that PCa cells have a hybrid cytoplasmic-mitochondrial TCA cycle that depends on IDH1. This metabolic enzyme represents a metabolic vulnerability of PCa cells and a potential new therapeutic target.

Citation Format: Kevin Gonthier, Cindy Weidmann, Line Berthiaume, Cynthia Jobin, Aurélie Lacouture, Camille Lafront, Mario Harvey, Bertrand Neveu, Jérémy Loehr, Alain Bergeron, Yves Fradet, Louis Lacombe, Julie Riopel, Éva Latulippe, Chantal Atallah, Michael Shum, Jean-Philippe Lambert, Frédéric Pouliot, Martin Pelletier, Étienne Audet-Walsh. Isocitrate dehydrogenase 1 sustains a hybrid cytoplasmic-mitochondrial tricarboxylic acid cycle in prostate cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3700.

Effects of Concentrated Long-Chain Omega-3 Polyunsaturated Fatty Acid Supplementation on Quality of Life after Radical Prostatectomy: A Phase II Randomized Placebo-Controlled Trial (RCT-EPA)

Prostate cancer (PCa) and associated treatments incur symptoms that may impact patients’ quality of life. Studies have shown beneficial relationships between diet, especially omega-3 fatty acids, and these symptoms. Unfortunately, only few data describing the relationship between long-chain omega-3 fatty acids (LCn3) and PCa-related symptoms in patients are available. The purpose of this study was to evaluate the effects of LCn3 supplementation on PCa-specific quality of life in 130 men treated by radical prostatectomy. Men were randomized to receive a daily dose of either 3.75 g of fish oil or a placebo starting 7 weeks before surgery and for up to one-year post-surgery. Quality of life was assessed using the validated EPIC-26 and IPSS questionnaires at randomization, at surgery, and every 3 months following surgery. Between-group differences were assessed using linear mixed models. Intention-to-treat analyses showed no significant difference between the two groups. However, at 12-month follow-up, per-protocol analyses showed a significantly greater increase in the urinary irritation function score (better urinary function) (MD = 5.5, p = 0.03) for the LCn3 group compared to placebo. These results suggest that LCn3 supplementation may improve the urinary irritation function in men with PCa treated by radical prostatectomy and support to conduct of larger-scale studies.

Efficacy and safety of pembrolizumab in metastatic urothelial carcinoma: results from KEYNOTE-045 and KEYNOTE-052 after up to 5 years of follow-up

BACKGROUND

Immune checkpoint inhibitors are a standard therapy in metastatic urothelial carcinoma (UC). Long-term follow-up is necessary to confirm durability of response and identify further safety concerns.

PATIENTS AND METHODS

In KEYNOTE-045, patients with metastatic UC that progressed on platinum-containing chemotherapy were randomly assigned 1:1 to receive pembrolizumab or investigator's choice of paclitaxel, docetaxel, or vinflunine. Primary endpoints were progression-free survival per RECIST version 1.1 by blinded independent central review (BICR) and overall survival. In KEYNOTE-052, cisplatin-ineligible patients with metastatic UC received first-line pembrolizumab. The primary endpoint was objective response rate per RECIST version 1.1 by BICR.

RESULTS

A total of 542 patients (pembrolizumab, n = 270; chemotherapy, n = 272) were randomly assigned in KEYNOTE-045. The median follow-up was 62.9 months (range 58.6-70.9 months; data cut-off 1 October 2020). At 48 months, overall survival rates were 16.7% for pembrolizumab and 10.1% for chemotherapy; progression-free survival rates were 9.5% and 2.7%, respectively. The median duration of response (DOR) was 29.7 months (range 1.6+ to 60.5+ months) for pembrolizumab and 4.4 months (range 1.4+ to 63.1+ months) for chemotherapy; 36-month DOR rates were 44.4% and 28.3%, respectively. A total of 370 patients were enrolled in KEYNOTE-052. The median follow-up was 56.3 months (range 51.2-65.3 months; data cut-off 26 September 2020). The confirmed objective response rate was 28.9% (95% confidence interval 24.3-33.8), and the median DOR was 33.4 months (range 1.4+ to 60.7+ months); the 36-month DOR rate was 44.8%. Most treatment-related adverse events for pembrolizumab in either study were grade 1 or 2 and manageable, which is consistent with prior reports.

CONCLUSION

With ∼5 years of follow-up, pembrolizumab monotherapy continued to demonstrate durable efficacy with no new safety signals in patients with platinum-resistant metastatic UC and as first-line therapy in cisplatin-ineligible patients.

CLINICAL TRIAL REGISTRY AND ID

With ClinicalTrials.gov NCT02256436 (KEYNOTE-045); https://clinicaltrials.gov/ct2/show/NCT02256436 and NCT02335424 (KEYNOTE-052); https://clinicaltrials.gov/ct2/show/NCT02335424.

UGT2B28 accelerates prostate cancer progression through stabilization of the endocytic adaptor protein HIP1 regulating AR and EGFR pathways

The androgen inactivating UGT2B28 pathway emerges as a predictor of progression in prostate cancer (PCa). However, the clinical significance of UGT2B28 tumoral expression and its contribution to PCa progression remain unclear. Using the Canadian Prostate Cancer Biomarker Network biobank (CPCBN; n = 1512), we analyzed UGT2B28 tumor expression in relation to clinical outcomes in men with localized PCa. UGT2B28 was overexpressed in tumors compared to paired normal adjacent prostatic tissue and was associated with inferior outcomes. Functional analyses indicated that UGT2B28 promoted cell proliferation, and its expression was regulated by the androgen receptor (AR)/ARv7. Mechanistically, UGT2B28 was shown to be a protein partner of the endocytic adaptor protein huntingtin-interacting protein 1 (HIP1), increasing its stability and priming AR/epidermal growth factor receptor (EGFR) pathways, leading to ERK1/2 activation triggering cell proliferation and epithelial-to-mesenchymal transition (EMT). HIP1 knockdown in UGT2B28 positive cells, and dual pharmacological targeting of AR and EGFR pathways, abolished cell proliferative advantages conferred by UGT2B28. In conclusion, UGT2B28 is a prognosticator of progression in localized PCa, regulates both AR and EGFR oncogenic signaling pathways via HIP1, and therefore can be therapeutically targeted by using combination of existing AR/EGFR inhibitors.

Analysis of sex-based differences to Bacillus Calmette-Guérin for non-muscle invasive bladder cancer

OBJECTIVE

To evaluate whether differences exist between men and women in response to intravesical BCG treatments. The incidence of urothelial carcinoma of the bladder is lower in women but they tend to present with more aggressive and advanced disease. Some prior studies also suggest there are sex-based differences in response to treatment for non-muscle invasive bladder tumors.

METHODS

In this retrospective study, we reviewed all consecutive patients who received BCG at the CHU de Québec - Laval University from 2009-2019. Men and women were treated with intravesical BCG therapy following pathologic confirmation of urothelial carcinoma. Outcomes evaluated include recurrence, progression, and treatment tolerability. Recurrence was defined as a pathology confirmed cancer whereas progression was the new development of high-grade (recurrence) pathology or an increase of stage. Tolerability was defined according to the proportion of prescribed BCG received. All clinical details were obtained through review of the medical records, collaborated by pharmacy records for BCG administration. Competing-risk analysis was used to compare outcomes.

RESULTS

Among 613 patients who received BCG at our institution between 2009-2019, 472 (77.0%) were men and 141 (23.0%) were women. The recurrence rate was not different between sexes, with a 5-year recurrence risk of 52% (95% CI: 36.93-65.4) among women compared to 57.5% (CI 95%: 51.9-62.6) among men. The overall non-progression rate at 1,3 and 5 years was 97.3% (95% CI: 95.6%-98.3%), 93.6% (95% CI: 91.2%-95.4%), and 91.7% (95% CI: 88.4%-94.1%), respectively. The completion of ≥5 induction BCG instillations and maintenance BCG use was similar in both genders.

CONCLUSIONS

We report a contemporary NMIBC cohort treated with BCG and find no clear evidence for sex-based differences in response to BCG treatment in regard of progression, recurrence, and tolerability.

Perception and satisfaction of patients after telemedicine urology consultations: A matched analysis with physicians' perspective

INTRODUCTION

During the first regional COVID-19 lockdown in March 2020, we conducted a study aimed at evaluating completeness of telemedicine consultation in urology. Of 1679 consultations, 67% were considered completely managed by phone. The aim of the present study was to assess patients' experience and satisfaction with telemedicine and to compare them with urologists' perceptions about quality and completeness of the telemedicine consultation.

METHODS

We contacted a randomly selected sample of patients (n=356) from our previous study to enquire about their experience. We used a home patient experience questionnaire, inspired by the Patient Experiences Questionnaire for Out-of-Hours Care (PEQOHC) and the Consumer Assessment Health Profile Survey (CAHPS).

RESULTS

Of 356 patients contacted, 315 agreed to complete the questionnaire. Urological consultations were for non-oncological (104), oncological (121), cancer suspicion (41), and pediatric (49) indications. Mean patient satisfaction score after telemedicine consultation was 8.8/10 (median 9/10) and 86.3% of patients rated the quality of the consultation as either excellent (54.6%) or very good (31.7%). Consultations regarding cancer suspicion had the lowest score (8.3/10). Overall, 46.7% of all patients would have preferred an in-person visit outside of the pandemic situation. Among patients whose consultations were rated suboptimal by urologists, almost a third more (31.2%) would have preferred an in-person visit (p=0.03).

CONCLUSIONS

Despite high reported patient satisfaction rates with telemedicine, it is noteworthy that nearly half of the patients would have preferred an in-person visit. Post-pandemic, it will be important to incorporate telemedicine as an alternative, while retaining and offering in-person visits.

Putative Biomarkers of Clinical Benefit With Pembrolizumab in Advanced Urothelial Cancer: Results from the KEYNOTE-045 and KEYNOTE-052 Landmark Trials

PURPOSE

In an exploratory analysis, we investigated the association between programmed death ligand 1 (PD-L1), tumor mutational burden (TMB), T-cell-inflamed gene expression profile (TcellinfGEP), and stromal signature with outcomes of pembrolizumab in urothelial carcinoma (UC).

PATIENTS AND METHODS

Patients with advanced UC received first-line pembrolizumab 200 mg every 3 weeks in the single-arm phase II KEYNOTE-052 trial (NCT02335424) and salvage pembrolizumab 200 mg every 3 weeks or chemotherapy (paclitaxel/docetaxel/vinflunine) in the randomized phase III KEYNOTE-045 trial (NCT02256436). The association of each biomarker (continuous variable) with objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) was evaluated using logistic regression (ORR) and Cox PH (PFS, OS), adjusted for ECOG PS; nominal P values were calculated without multiplicity adjustment (one-sided, pembrolizumab; two-sided, chemotherapy). Significance was prespecified at α = 0.05.

RESULTS

In KEYNOTE-052, PD-L1, TMB, and TcellinfGEP were significantly associated with improved outcomes; stromal signature was significantly associated with worse outcomes. In KEYNOTE-045, although findings for TMB and TcellinfGEP with pembrolizumab were consistent with those of KEYNOTE-052, PD-L1 was not significantly associated with improved outcomes, nor was stromal signature associated with worse outcomes with pembrolizumab; chemotherapy was not associated with outcomes in a consistent manner for any of the biomarkers. Hazard ratio (HR) estimates at prespecified cutoffs showed an advantage for pembrolizumab versus chemotherapy regardless of PD-L1 or TMB, with a trend toward lower HRs in the combined positive score ≥10 and the TMB ≥175 mutation/exome subgroup. For TcellinfGEP, PFS and OS HRs were lower in the TcellinfGEP-nonlow subgroup regardless of treatment.

CONCLUSIONS

Multiple biomarkers characterizing the tumor microenvironment may help predict response to pembrolizumab monotherapy in UC, and potential clinical utility of these biomarkers may be context-dependent.

Multiple metabolic pathways fuel the truncated tricarboxylic acid cycle of the prostate to sustain constant citrate production and secretion

Objective

The prostate is metabolically unique: it produces high levels of citrate for secretion via a truncated tricarboxylic acid (TCA) cycle to maintain male fertility. In prostate cancer (PCa), this phenotype is reprogrammed, making it an interesting therapeutic target. However, how the truncated prostate TCA cycle works is still not completely understood.

Methods

We optimized targeted metabolomics in mouse and human organoid models in ex vivo primary culture. We then used stable isotope tracer analyses to identify the pathways that fuel citrate synthesis.

Results

First, mouse and human organoids were shown to recapitulate the unique citrate-secretory program of the prostate, thus representing a novel model that reproduces this unusual metabolic profile. Using stable isotope tracer analysis, several key nutrients were shown to allow the completion of the prostate TCA cycle, revealing a much more complex metabolic profile than originally anticipated. Indeed, along with the known pathway of aspartate replenishing oxaloacetate, glutamine was shown to fuel citrate synthesis through both glutaminolysis and reductive carboxylation in a GLS1-dependent manner. In human organoids, aspartate entered the TCA cycle at the malate entry point, upstream of oxaloacetate. Our results demonstrate that the citrate-secretory phenotype of prostate organoids is supported by the known aspartate–oxaloacetate–citrate pathway, but also by at least three additional pathways: glutaminolysis, reductive carboxylation, and aspartate–malate conversion.

Conclusions

Our results add a significant new dimension to the prostate citrate-secretory phenotype, with at least four distinct pathways being involved in citrate synthesis. Better understanding this distinctive citrate metabolic program will have applications in both male fertility as well as in the development of novel targeted anti-metabolic therapies for PCa.

•

Targeted metabolomics and stable isotope tracer analysis were optimized in mouse and human prostate organoids.

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Organoids recapitulate the unique citrate-secretory phenotype of the prostate.

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Glutamine fuels citrate synthesis for secretion by glutaminolysis and reductive carboxylation.

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Aspartate enters the TCA cycle at different entry points in mouse and human prostate organoids for citrate production.

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We revealed a much more complex TCA cycle in the prostate than originally anticipated.

Sex steroid modulation of macrophages within the prostate tumor microenvironment

BACKGROUND

The role of androgens and other sex steroids is known to influence the prognosis and progression of prostate cancer through different disease states. While androgens are generally regarded as immunosuppressive and estrogens as inflammatory, the specific influence of sex steroids on the immune microenvironment of prostate tumors remains incompletely understood.

MATERIAL AND METHODS

In this study, we evaluate the link between sex steroids and prostate cancer immune cells, particularly macrophages. Using in vitro and in vivo models, as well as ex vivo culture of patient prostate tissue, we evaluated the influence of androgen, estrogen, and progesterone on immune cells of the prostate microenvironment.

RESULTS

In vitro, we observed sex steroids induced indirect changes on prostate cancer cell proliferation via THP-1 derived macrophages, but no clear changes were induced using human monocyte derived macrophages. Comparing immunohistochemistry for immunosuppressive macrophage marker CD163 with concomitant circulating sex steroids from the same patients, we observed a correlation with higher dehydroepiandrosterone (DHEA)-sulfate and estrone-sulfate levels associated with higher prostate CD163 expression. Similar relationships between DHEA and CD163 levels were observed in ex vivo cultured prostate biopsies. Finally, in a murine prostate cancer model of long-term sex steroids we observed significant differences in tumor growth in mice implanted with estrogen and DHEA diffusion tubes.

CONCLUSIONS

Our results highlight the complex influence of sex steroids on the immune cell composition of prostate tumors. Understanding this biology may help to further personalized therapy and improve patient outcomes.

A Natural Polyphenol Exerts Antitumor Activity and Circumvents Anti-PD-1 Resistance through Effects on the Gut Microbiota

Several approaches to manipulate the gut microbiome for improving the activity of cancer immune-checkpoint inhibitors (ICI) are currently under evaluation. Here, we show that oral supplementation with the polyphenol-rich berry camu-camu (CC; Myrciaria dubia) in mice shifted gut microbial composition, which translated into antitumor activity and a stronger anti-PD-1 response. We identified castalagin, an ellagitannin, as the active compound in CC. Oral administration of castalagin enriched for bacteria associated with efficient immunotherapeutic responses (Ruminococcaceae and Alistipes) and improved the CD8+/FOXP3+CD4+ ratio within the tumor microenvironment. Moreover, castalagin induced metabolic changes, resulting in an increase in taurine-conjugated bile acids. Oral supplementation of castalagin following fecal microbiota transplantation from ICI-refractory patients into mice supported anti-PD-1 activity. Finally, we found that castalagin binds to Ruminococcus bromii and promoted an anticancer response. Altogether, our results identify castalagin as a polyphenol that acts as a prebiotic to circumvent anti-PD-1 resistance.

SIGNIFICANCE

The polyphenol castalagin isolated from a berry has an antitumor effect through direct interactions with commensal bacteria, thus reprogramming the tumor microenvironment. In addition, in preclinical ICI-resistant models, castalagin reestablishes the efficacy of anti-PD-1. Together, these results provide a strong biological rationale to test castalagin as part of a clinical trial. This article is highlighted in the In This Issue feature, p. 873.

Association of TMB and PD-L1 with efficacy of first-line pembrolizumab (pembro) or pembro + chemotherapy (chemo) versus chemo in patients (pts) with advanced urothelial carcinoma (UC) from KEYNOTE-361

540

Background: The 3-arm, open-label, phase 3 KEYNOTE-361 study (NCT02853305) evaluated first-line pembro ± chemo vs chemo in advanced UC regardless of PD-L1 status. The trial did not meet its primary end points of superior PFS and OS with pembro + chemo vs chemo and thus analysis of pembro monotherapy (mono) vs chemo was exploratory. We explored the association of TMB status and PD-L1 combined positive score (CPS) with clinical outcomes in KEYNOTE-361. Methods: In pts with TMB and/or PD-L1 data, the association between TMB (via whole exome sequencing) and PD-L1 (via PD-L1 IHC 22C3 pharmDx) and clinical outcomes (ORR, PFS, and OS) was evaluated. In each treatment arm, the hypotheses regarding the associations were evaluated using logistic regression (ORR) and Cox proportional hazards regression (PFS; OS), and 1-sided (pembro; pembro + chemo) and 2-sided (chemo) P values were calculated; significance was prespecified at α = 0.05 without multiplicity adjustment. Clinical utility was assessed using prespecified cutoffs of 175 mut/exome (TMB) and CPS 10 (PD-L1). Clinical data cutoff was April 29, 2020. Results: 820/993 pts (82.6%) had evaluable TMB data (pembro, 252; pembro + chemo, 282; chemo, 286). TMB (log10) was significantly positively associated with ORR, PFS, and OS for pembro ( P < 0.001, < 0.001, and 0.007, respectively) and PFS and OS for pembro + chemo ( P= 0.007 and 0.010, respectively). The area under the receiver operating characteristics (AUROC) curve (95% CI) for discriminating response was 0.64 (0.56-0.71) for pembro, 0.53 (0.46-0.60) for pembro + chemo, and 0.52 (0.45-0.59) for chemo. Efficacy by TMB cutoff is reported in the Table. All 993 pts had PD-L1 data (pembro, 302; pembro + chemo, 349; chemo, 342). PD-L1 was significantly positively associated with PFS for pembro ( P= 0.006) and ORR for pembro + chemo ( P= 0.042) but not chemo. Efficacy by PD-L1 CPS is reported in the Table. Conclusions: Strong associations were observed between TMB and all 3 clinical outcomes (ORR, PFS, and OS) with pembro mono in the first-line setting and a reduced association was observed between TMB and clinical outcomes with pembro + chemo. No consistent associations were observed between PD-L1 and clinical outcomes with pembro mono or pembro + chemo. Clinical trial information: NCT02853305. [Table: see text]

Post hoc pooled analysis of first-line (1L) pembrolizumab (pembro) for advanced urothelial carcinoma (UC): Outcomes by response at week nine in KEYNOTE-052 and KEYNOTE-361

519

Background: Pembro is a 1L treatment for cisplatin-ineligible pts with UC. This post hoc landmark analysis evaluated clinical outcomes by response at 9 wk to 1L pembro monotherapy in pts with advanced/unresectable or metastatic UC from the single-arm phase 2 KEYNOTE-052 (NCT02335424) and the randomized phase 3 KEYNOTE-361 (NCT02853305) trials. Methods: Cisplatin-ineligible pts with advanced UC were enrolled in KEYNOTE-052 and received pembro (200 mg Q3W for ≤2 y). Platinum-eligible pts with advanced UC who had not previously received systemic chemotherapy (chemo) were enrolled in KEYNOTE-361 and randomly assigned 1:1:1 to receive pembro (200 mg Q3W for ≤2 y), pembro + chemo (1000 mg/m2 gemcitabine on d1 and d8 + cisplatin [70 mg/m2] or carboplatin [AUC 5] on d1 of each 3-wk cycle), or chemo. The primary analysis group included pembro monotherapy–treated pts; the sensitivity analysis group included pembro monotherapy–treated pts from KEYNOTE-052 and the choice of carboplatin subpopulation of pembro monotherapy–treated pts from KEYNOTE-361. Landmark analyses of OS by pts with CR, PR, SD, or PD per RECIST v1.1 by BICR at first imaging assessment (wk 9) were pooled for the ITT populations. Duration of CR/PR/SD and OS were estimated using the Kaplan-Meier method. Data cutoffs were Sep 26, 2020 (KEYNOTE-052) and Apr 29, 2020 (KEYNOTE-361). Results: The primary analysis group included 681 pembro-treated pts (KEYNOTE-052, N = 374; KEYNOTE-361, N = 307); the sensitivity analysis group included 544 pembro-treated pts (KEYNOTE-052, N = 374; KEYNOTE-361, N = 170). Median time from randomization to cutoff was 51.9 mo (range, 22.0-65.3) and 53.7 mo (range, 22.0-65.3) for the primary and sensitivity analysis groups, respectively. Twenty-five pts (4.6%) had CR and 135 (24.6%) had PR (primary group); 17 pts (3.9%) had CR and 105 (24.1%) had PR (sensitivity group). Median DOR was 25.9 mo for pts with CR/PR at wk 9; pts with CR/PR or SD at wk 9 had longer OS than pts with PD at wk 9 (Table). Conclusions: In this post hoc analysis, pts with advanced UC in KEYNOTE-052 and KEYNOTE-361 with CR/PR at wk 9 had better clinical outcomes with pembro monotherapy than pts with SD or PD; 1L pembro monotherapy continues to show efficacy in advanced UC. Clinical trial information: NCT02335424 and NCT02853305. [Table: see text]

Impact of primary tumor location on efficacy and safety of pembrolizumab (pembro) in patients (pts) with locally advanced or metastatic urothelial carcinoma (UC) enrolled in the phase 2 KEYNOTE-052 and phase 3 KEYNOTE-045 trials

516

Background: Pembro showed antitumor activity in 1L and 2L for pts with UC in the single-arm, phase 2 KEYNOTE-052 study (NCT02335424) and the randomized phase 3 KEYNOTE-045 (NCT02256436) study, respectively. This post hoc exploratory analysis evaluated whether primary tumor location affected efficacy and safety of pembro (KEYNOTE-052; KEYNOTE-045) and chemotherapy (chemo; KEYNOTE-045). Methods: KEYNOTE-052 enrolled cisplatin-ineligible pts with advanced/metastatic UC who had not previously received systemic therapy; they received pembro (200 mg IV Q3W). KEYNOTE-045 enrolled pts with advanced/metastatic UC who had received platinum-containing chemo; pts were randomly assigned 1:1 to receive pembro (200 mg IV Q3W) or investigator’s choice of chemo (paclitaxel, docetaxel, or vinflunine). Both studies required pts to have measurable disease per RECIST v1.1. Upper tract (UT) UC included primary tumors in the renal pelvis or ureter; lower tract (LT) UC included primary tumors in the bladder or urethra. Pts with UT and LT disease (UT/LT) were classified as LT. Pts receiving pembro were treated until disease progression, unacceptable toxicity, or withdrawal of consent, for up to 2y. End points were PFS, ORR, and DOR per RECIST v1.1 by central radiology assessment and OS. Results: A total of 369 pembro-treated pts (68 UT; 301 LT [79 UT/LT]) from KEYNOTE-052 plus 270 pembro-treated pts (93 UT; 177 LT [33 UT/LT]) and 272 chemo-treated pts (94 UT; 178 LT) from KEYNOTE-045 were evaluated. Median follow-up from randomization to data cutoff (09/26/20 and 10/1/20, respectively) was ≥56 mo. Both studies enrolled a similar percentage of pts with PD-L1–positive tumors (25%-30%). PFS, ORR, DOR, and OS for pembro were consistent regardless of tumor location, although ORR for KEYNOTE-045 was lower for the UT group (Table). In the chemo arm of KEYNOTE-045, similar efficacy was observed regardless of tumor location or regimen. Grade 3-5 TRAEs occurred at similar rates in KEYNOTE-052 (19.1% UT; 21.6% LT) and KEYNOTE-045 (17.2% UT; 16.8% LT). Conclusions: In this exploratory analysis, pembro showed similar clinical activity and manageable safety regardless of primary UC tumor location. Clinical trial information: NCT02256436 and NCT02335424. [Table: see text]

Post hoc analysis of the efficacy of pembrolizumab retreatment after progression of advanced urothelial carcinoma (UC) in KEYNOTE-045 and KEYNOTE-052

512

Background: Pembrolizumab (pembro) has shown efficacy in advanced/unresectable and metastatic UC (mUC). There is interest in determining whether pts should be treated subsequently with checkpoint inhibitors such as anti–PD-1 therapy if mUC responds then later progresses. Pembro retreatment after disease progression has shown efficacy in melanoma and NSCLC. This post hoc exploratory analysis investigated the efficacy of pembro retreatment for pts with advanced UC or mUC enrolled in KEYNOTE-045 and KEYNOTE-052 with a best overall response (BOR) of SD or better and whose disease progressed after discontinuation or completion of 2 y of therapy. Methods: The phase 3 KEYNOTE-045 trial (NCT02256436) was designed to compare the efficacy and safety of pembro vs chemotherapy (chemo) in pts with mUC that recurred/progressed on platinum containing chemo; ≤2 prior lines of systemic chemo for mUC were permitted. The phase 2 KEYNOTE-052 trial (NCT02335424) was designed to evaluate the efficacy and safety of first-line pembro in cisplatin-ineligible pts with advanced UC. In both studies, pembro was administered for up to 2 y; pts were eligible for retreatment if they stopped pembro after CR or had a BOR of CR, PR, or SD and completed 2 y of treatment. Pts must have investigator-confirmed radiographic PD after therapy cessation, have ECOG PS score 0-1, and not have received anticancer treatment after the last pembro dose. BOR to retreatment is reported. Results: At data cutoff for KEYNOTE-045 (Oct 1, 2020), 11 pts were retreated: 5 (45%) achieved objective response to retreatment (3 CR; 2 PR; Table) and 6 had SD, for a disease control rate (DCR; CR+PR+SD) of 100%. Median treatment-free interval was 7.7 mo (IQR, 3.6-16.5); median duration of retreatment was 11.4 mo (IQR, 7.6-12.0). Seven pts (64%) were alive at cutoff. At data cutoff for KEYNOTE-052 (Sep 26, 2020), 10 pts were retreated; 5 (50%) had objective response to retreatment (1 CR; 4 PR) and 4 had SD, for a DCR of 90%. Retreatment BOR was PD for 1 pt (10%). Median treatment-free interval was 13.0 mo (9.2-16.6); median duration of retreatment was 6.0 mo (IQR, 4.9-9.2). Four pts (40%) were alive at cutoff. Conclusions: Although the number of pts who received retreatment was small, objective responses were observed. The findings are generally consistent with observations from retreatment in other tumor types (e.g., melanoma). Clinical trial information: NCT02256436 and NCT02335424. [Table: see text]

Abstract P001: The gut microbiome-prostate tumor crosstalk is modulated by dietary polyunsaturated fatty acids

Introduction and Objective: Recently, gut microbiota emerged as an important factor for success of immunity-based cancer treatments. However, its steady-state interaction and contribution to developing tumors is largely unexplored in non-intestinal cancers. Our objective was to investigate the connection between prostate tumor and the gut microbiota independently of cancer therapies.

Methods: Human fecal samples were obtained from men participating into a phase IIb double-blind randomized controlled trial testing 3g/day of monoglyceride-eicosapentaenoic acid (MAG-EPA) versus placebo for a 4-10 week period before their radical prostatectomy (NCT02333435). A second set of samples were from men taking the same intervention of MAG-EPA or placebo after a PSA increase following their radical prostatectomy (NCT03753334). Short chain fatty acids (SCFA) analysis of patient stool samples between baseline and surgery was performed by gas chromatography coupled with flame ionization detection. 16srRNA libraries were amplified by targeting a fragment of the V3-V4 hypervariable region of the bacterial 16S rRNA gene. High-throughput sequencing of the bar-coded amplicons was performed on a MiSeq apparatus and the bioinformatics analysis was conducted using Mothur pipeline. In addition to human fecal samples, fully immunocompetent C57BL/6 mice were injected subcutaneously with TRAMP-C2 or PTEN−/− or PTEN−/− RB1−/− mouse prostate cancer cells to measure changes in the gut microbiota during tumor growth. We also recapitulated the MAG-EPA intervention in our TRAMP-C2 mice model and fed by gavage four different fatty acids (omega-9 (high oleic sunflower oil), omega-6 (MAG-arachidonic acid) and two omega-3 (MAG-docosahexaenoic and MAG-EPA).

Results: In human fecal samples from prostate cancer patients, we observed a reduced gut microbiota diversity correlating with tumor stage. We also found that tumor growth was sufficient to modulate the microbiota in three independent prostate cancer syngeneic mouse models. We showed that transplanted human gut flora was sufficient to modulate ectopic prostate tumor growth, supporting the causal impact of gut microbiota for prostate cancer. The analysis of SCFA in patient stool samples between baseline and surgery showed that MAG-EPA prebiotic intervention was associated with a decrease of fecal butyric acid levels in prostate cancer patients with downgrade at surgery. We finally investigated this gut-tumor connection using purified polyunsaturated fatty acids prebiotics in patients and mice. We observed a reduction in the levels of Ruminococcaceae following dietary omega-3 supplementation that correlated with prostate cancer downgrade in patients and reduced tumor growth in mice.

Conclusion: Overall our findings suggest that diet-actionable components of the gut microbiome can regulate prostate cancer growth.

Citation Format: Jalal Laaraj, Gabriel Lachance, Nikunj Gevariya, Thibaut Varin, Andrei Feldiorean, Fanny Gaignier, Isabelle Boudreau Julien, Hui Wen Xu, Tarek Hallal, Jean-François Pelletier, Sidki Bouslama, Nadia Boufaied, Nicolas Derome, Yves Fradet, Leigh Ellis, Ciriaco A. Piccirillo, Frédéric Raymond, David P. Labbé, Alain Bergeron, André Marette, Karine Robitaille, Vincent Fradet. The gut microbiome-prostate tumor crosstalk is modulated by dietary polyunsaturated fatty acids [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2021 Oct 5-6. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(1 Suppl):Abstract nr P001.

Subversion of infiltrating prostate macrophages to a mixed immunosuppressive tumor-associated macrophage phenotype

Tumor-associated macrophages (TAMs) support tumor progression within the tumor microenvironment (TME). Many questions remain as to the origin, development, and function of TAMs within the prostate TME. Evaluation of TAMs in prostate cancer (PCa) patients identified the immunosuppressive TAM marker CD163 in adjacent normal epithelium as an independent predictor of metastases or PCa death. Flow cytometry analyses identified prostate TAMs as frequently expressing both proinflammatory M1 (CCR7+) and immunosuppressive M2 (CD163+) markers. In vitro, we demonstrate PCa cells similarly subvert human M1 macrophages toward a mixed M1/M2 macrophage phenotype favoring tumor growth. Further the cytokine milieu-induced transition between immunosuppressive M2 to proinflammatory M1 (M2→M1) macrophages is abrogated by the presence of PCa cells. RNA sequencing suggests alterations in chemokine expression in prostate TAMs due to the presence of PCa cells. Together, our results suggest that prostate TAMs originate from inflammatory infiltrating macrophages, which are then reprogrammed mainly by PCa cells, but also the cytokine milieu. A better understanding of this subversion of macrophages within the prostate may lead to novel treatment strategies.

Identification of Morphologic Criteria Associated with Biochemical Recurrence in Intraductal Carcinoma of the Prostate

Intraductal carcinoma of the prostate (IDC-P) is an aggressive subtype of prostate cancer strongly associated with an increased risk of biochemical recurrence (BCR). However, approximately 40% of men with IDC-P remain BCR-free five years after radical prostatectomy. In this retrospective multicenter study, we aimed to identify histologic criteria associated with BCR for IDC-P lesions. A total of 108 first-line radical prostatectomy specimens were reviewed. In our test cohort (n = 39), presence of larger duct size (>573 µm in diameter), cells with irregular nuclear contours (CINC) (≥5 CINC in two distinct high-power fields), high mitotic score (>1.81 mitoses/mm2), blood vessels, and comedonecrosis were associated with early BCR (<18 months) (p < 0.05). In our validation cohort (n = 69), the presence of CINC or blood vessels was independently associated with an increased risk of BCR (hazard ratio [HR] 2.32, 95% confidence interval [CI] 1.09-4.96, p = 0.029). When combining the criteria, the presence of any CINC, blood vessels, high mitotic score, or comedonecrosis showed a stronger association with BCR (HR 2.74, 95% CI 1.21-6.19, p = 0.015). Our results suggest that IDC-P can be classified as low versus high-risk of BCR. The defined morphologic criteria can be easily assessed and should be integrated for clinical application following validation in larger cohorts.

Abstract LBA030: DPX-SurMAGE, a novel dual-targeted immunotherapy for bladder cancer, induces target-specific T cells with a favorable safety profile in preclinical model

Thirty to forty percent of high-risk non-muscle invasive bladder cancer (NMIBC) fail standard of care, leaving radical cystectomy as the most recommended option for these patients. Therefore, new efficient and tolerable treatments are required to prevent or delay cystectomy. The DPX platform is a unique, water-free, lipid-based formulation that can deliver peptides, proteins, and small molecules specifically to antigen presenting cells (APCs), eliciting a targeted, robust, and sustained T cell-based immune response. Peptides that are packaged in DPX are specifically taken up by APCs. Maveropepimut-S (MVP-S, formerly known as DPX-Survivac) incorporates 5 HLA-restricted peptides derived from the anti-apoptotic protein survivin and is the first DPX-based immunotherapy. MVP-S demonstrated survivin-specific and sustained T cell response along with clinical activity and limited adverse events in patients with solid and hematologic tumors. Survivin and MAGE-A9 are well characterized tumor-associated antigens (TAAs) frequently overexpressed in bladder tumours. The DPX platform was leveraged to develop a new dual-targeted T cell activating immunotherapy, DPX-SurMAGE, incorporating HLA-A2 restricted peptides of both survivin and MAGE-A9. The feasibility of packaging peptides targeting two different TAAs into the DPX platform was assessed by performing comparative immunogenicity evaluation between 2 MVP-S peptides and DPX-SurMAGE in HLA-A2 transgenic mice. The magnitude of peptide-specific T cell responses against the shared HLA-A2 survivin peptide was similar in animals immunized with either DPX-SurMAGE or MVP-S indicating that the presence of MAGE-A9 peptides did not affect the immunogenicity of the MVP-S-based survivin peptide in the DPX-SurMAGE formulation. Immunogenicity and toxicity of DPX-SurMAGE with and without metronomic cyclophosphamide (mCPA) was further evaluated. IFN-γ ELISPOT assessment demonstrated robust induction of peptide-specific T cell responses to survivin and MAGE-A9 peptide pools. These strong responses were maintained at similar levels in the long-term chronic phase of the assessments both with and without mCPA. Preliminary safety observations including Detailed Clinical Examination (DCE), body weights and organ weights showed no sign of toxicity nor significant changes in mice treated with DPX-SurMAGE with or without mCPA. There were no significant differences in injection site reactions between DPX-SurMAGE groups (with and without mCPA). The local injection site reactions for DPX-SurMAGE groups were comparable to that of DPX-Empty control group. This study demonstrates the unique ability of the DPX delivery platform to deliver multiple antigenic TAA peptides without compromising the immunogenicity of each peptide. Furthermore, the DPX-SurMAGE treatment was well tolerated and was shown to induce robust and sustained target-specific T cell responses against both survivin and MAGE-A9 antigens, supporting the impending phase 1 clinical trial in high risk NMIBC patients.

Citation Format: Valérie Picard, Valarmathy Kaliaperumal, Fanny Gaignier, Marjorie Besançon, Yogesh Bramhecha, Olga Hrytsenko, Alecia McKay, Stephan Fiset, Alain Bergeron, Yves Fradet. DPX-SurMAGE, a novel dual-targeted immunotherapy for bladder cancer, induces target-specific T cells with a favorable safety profile in preclinical model [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr LBA030.

Dimensional reduction based on peak fitting of Raman micro spectroscopy data improves detection of prostate cancer in tissue specimens

SIGNIFICANCE

Prostate cancer is the most common cancer among men. An accurate diagnosis of its severity at detection plays a major role in improving their survival. Recently, machine learning models using biomarkers identified from Raman micro-spectroscopy discriminated intraductal carcinoma of the prostate (IDC-P) from cancer tissue with a ≥85  %   detection accuracy and differentiated high-grade prostatic intraepithelial neoplasia (HGPIN) from IDC-P with a ≥97.8  %   accuracy.

AIM

To improve the classification performance of machine learning models identifying different types of prostate cancer tissue using a new dimensional reduction technique.

APPROACH

A radial basis function (RBF) kernel support vector machine (SVM) model was trained on Raman spectra of prostate tissue from a 272-patient cohort (Centre hospitalier de l'Université de Montréal, CHUM) and tested on two independent cohorts of 76 patients [University Health Network (UHN)] and 135 patients (Centre hospitalier universitaire de Québec-Université Laval, CHUQc-UL). Two types of engineered features were used. Individual intensity features, i.e., Raman signal intensity measured at particular wavelengths and novel Raman spectra fitted peak features consisting of peak heights and widths.

RESULTS

Combining engineered features improved classification performance for the three aforementioned classification tasks. The improvements for IDC-P/cancer classification for the UHN and CHUQc-UL testing sets in accuracy, sensitivity, specificity, and area under the curve (AUC) are (numbers in parenthesis are associated with the CHUQc-UL testing set): +4  %   (+8  %  ), +7  %   (+9  %  ), +2  %   (6%), +9 (+9) with respect to the current best models. Discrimination between HGPIN and IDC-P was also improved in both testing cohorts: +2.2  %   (+1.7  %  ), +4.5  %   (+3.6  %  ), +0  %   (+0  %  ), +2.3 (+0). While no global improvements were obtained for the normal versus cancer classification task [+0  %   (-2  %  ), +0  %   (-3  %  ), +2  %   (-2  %  ), +4 (+3)], the AUC was improved in both testing sets.

CONCLUSIONS

Combining individual intensity features and novel Raman fitted peak features, improved the classification performance on two independent and multicenter testing sets in comparison to using only individual intensity features.

Identification of Abundant and Functional dodecaRNAs (doRNAs) Derived from Ribosomal RNA

Using a modified RNA-sequencing (RNA-seq) approach, we discovered a new family of unusually short RNAs mapping to ribosomal RNA 5.8S, which we named dodecaRNAs (doRNAs), according to the number of core nucleotides (12 nt) their members contain. Using a new quantitative detection method that we developed, we confirmed our RNA-seq data and determined that the minimal core doRNA sequence and its 13-nt variant C-doRNA (doRNA with a 5' Cytosine) are the two most abundant doRNAs, which, together, may outnumber microRNAs. The C-doRNA/doRNA ratio is stable within species but differed between species. doRNA and C-doRNA are mainly cytoplasmic and interact with heterogeneous nuclear ribonucleoproteins (hnRNP) A0, A1 and A2B1, but not Argonaute 2. Reporter gene activity assays suggest that C-doRNA may function as a regulator of Annexin II receptor (AXIIR) expression. doRNAs are differentially expressed in prostate cancer cells/tissues and may control cell migration. These findings suggest that unusually short RNAs may be more abundant and important than previously thought.

Follicle-stimulating hormone (FSH) levels prior to prostatectomy are not related to long-term oncologic or cardiovascular outcomes for men with prostate cancer

Prior research suggests a link between circulating levels of follicle-stimulating hormone (FSH) and prostate cancer outcomes. FSH levels may also explain some of the observed differences in cardiovascular events among men treated with gonadotropin-releasing hormone (GnRH) antagonists compared to GnRH agonists. This study evaluates the association between preoperative FSH and long-term cardiovascular and oncologic outcomes in a cohort of men with long follow-up after radical prostatectomy. We performed a cohort study utilizing an institutional biobank with annotated clinical data. FSH levels were measured from cryopreserved plasma and compared with sex steroids previously measured from the same samples. Differences in oncologic outcomes between tertiles of FSH levels were compared using adjusted cox regression models. Major adverse cardiovascular events (MACE) were similarly assessed using hospital admission diagnostic codes. A total of 492 patients were included, with a median follow-up of 13.1 (interquartile range: 8.9–15.9) years. Dehydroepiandrosterone sulfate (DHEA-S) levels, but not other androgens, negatively correlated with FSH levels on linear regression analysis (P = 0.03). There was no association between FSH tertile and outcomes of biochemical recurrence, time to castrate-resistant prostate cancer, or time to metastasis. MACEs were identified in 50 patients (10.2%), with a mean time to first event of 8.8 years. No association with FSH tertile and occurrence of MACE was identified. Our results do not suggest that preoperative FSH levels are significantly associated with oncologic outcomes among prostate cancer patients treated with radical prostatectomy, nor do these levels appear to be predictors of long-term cardiovascular risk.

Pembrolizumab alone or combined with chemotherapy versus chemotherapy as first-line therapy for advanced urothelial carcinoma (KEYNOTE-361): a randomised, open-label, phase 3 trial

BACKGROUND

PD-1 and PD-L1 inhibitors are active in metastatic urothelial carcinoma, but positive randomised data supporting their use as a first-line treatment are lacking. In this study we assessed outcomes with first-line pembrolizumab alone or combined with chemotherapy versus chemotherapy for patients with previously untreated advanced urothelial carcinoma.

METHODS

KEYNOTE-361 is a randomised, open-label, phase 3 trial of patients aged at least 18 years, with untreated, locally advanced, unresectable, or metastatic urothelial carcinoma, with an Eastern Cooperative Oncology Group performance status of up to 2. Eligible patients were enrolled from 201 medical centres in 21 countries and randomly allocated (1:1:1) via an interactive voice-web response system to intravenous pembrolizumab 200 mg every 3 weeks for a maximum of 35 cycles plus intravenous chemotherapy (gemcitabine [1000 mg/m²] on days 1 and 8 and investigator's choice of cisplatin [70 mg/m²] or carboplatin [area under the curve 5] on day 1 of every 3-week cycle) for a maximum of six cycles, pembrolizumab alone, or chemotherapy alone, stratified by choice of platinum therapy and PD-L1 combined positive score (CPS). Neither patients nor investigators were masked to the treatment assignment or CPS. At protocol-specified final analysis, sequential hypothesis testing began with superiority of pembrolizumab plus chemotherapy versus chemotherapy alone in the total population (all patients randomly allocated to a treatment) for the dual primary endpoints of progression-free survival (p value boundary 0·0019), assessed by masked, independent central review, and overall survival (p value boundary 0·0142), followed by non-inferiority and superiority of overall survival for pembrolizumab versus chemotherapy in the patient population with CPS of at least 10 and in the total population (also a primary endpoint). Safety was assessed in the as-treated population (all patients who received at least one dose of study treatment). This study is completed and is no longer enrolling patients, and is registered at ClinicalTrials.gov, number NCT02853305.

FINDINGS

Between Oct 19, 2016 and June 29, 2018, 1010 patients were enrolled and allocated to receive pembrolizumab plus chemotherapy (n=351), pembrolizumab monotherapy (n=307), or chemotherapy alone (n=352). Median follow-up was 31·7 months (IQR 27·7-36·0). Pembrolizumab plus chemotherapy versus chemotherapy did not significantly improve progression-free survival, with a median progression-free survival of 8·3 months (95% CI 7·5-8·5) in the pembrolizumab plus chemotherapy group versus 7·1 months (6·4-7·9) in the chemotherapy group (hazard ratio [HR] 0·78, 95% CI 0·65-0·93; p=0·0033), or overall survival, with a median overall survival of 17·0 months (14·5-19·5) in the pembrolizumab plus chemotherapy group versus 14·3 months (12·3-16·7) in the chemotherapy group (0·86, 0·72-1·02; p=0·0407). No further formal statistical hypothesis testing was done. In analyses of overall survival with pembrolizumab versus chemotherapy (now exploratory based on hierarchical statistical testing), overall survival was similar between these treatment groups, both in the total population (15·6 months [95% CI 12·1-17·9] with pembrolizumab vs 14·3 months [12·3-16·7] with chemotherapy; HR 0·92, 95% CI 0·77-1·11) and the population with CPS of at least 10 (16·1 months [13·6-19·9] with pembrolizumab vs 15·2 months [11·6-23·3] with chemotherapy; 1·01, 0·77-1·32). The most common grade 3 or 4 adverse event attributed to study treatment was anaemia with pembrolizumab plus chemotherapy (104 [30%] of 349 patients) or chemotherapy alone (112 [33%] of 342 patients), and diarrhoea, fatigue, and hyponatraemia (each affecting four [1%] of 302 patients) with pembrolizumab alone. Six (1%) of 1010 patients died due to an adverse event attributed to study treatment; two patients in each treatment group. One each occurred due to cardiac arrest and device-related sepsis in the pembrolizumab plus chemotherapy group, one each due to cardiac failure and malignant neoplasm progression in the pembrolizumab group, and one each due to myocardial infarction and ischaemic colitis in the chemotherapy group.

INTERPRETATION

The addition of pembrolizumab to first-line platinum-based chemotherapy did not significantly improve efficacy and should not be widely adopted for treatment of advanced urothelial carcinoma.

FUNDING

Merck Sharp and Dohme, a subsidiary of Merck, Kenilworth, NJ, USA.

Pembrolizumab plus enzalutamide for enzalutamide-resistant metastatic castration-resistant prostate cancer (mCRPC): Updated analyses after one additional year of follow-up from cohorts 4 and 5 of the KEYNOTE-199 study

5042

Background: KEYNOTE-199 (NCT02787005) is a multicohort phase 2 study to evaluate pembrolizumab (pembro) in mCRPC. A previous analysis of patients with RECIST-measurable (cohort 4 [C4]) or bone-predominant nonmeasurable (cohort 5 [C5]) disease who were chemotherapy-naive and had progression while on enzalutamide (enza) found that pembro + enza showed antitumor activity and manageable safety. Long-term outcomes are of interest with immunotherapy; hence, updated efficacy and safety data after an additional 1 year of follow-up are presented. Methods: Pts were eligible if they had resistance to enza after prior response. Prior treatment with abiraterone was allowed. Pts received pembro 200 mg Q3W for up to 35 cycles + enza QD until progression, unacceptable toxicity, or withdrawal. Primary end point was ORR per RECIST v1.1 by blinded independent central review (BICR) in C4. Secondary end points were DOR (C4), and DCR, rPFS, OS and safety (both cohorts). Results: 126 pts (C4, 81; C5, 45) were treated. Median age was 72 years (range 43-92), 32.5% had visceral disease and 87.3% previously received ≥6 mo of enzalutamide; 121 pts (96.0%) discontinued, most because of progressive disease. Median (range) time from enrollment to data cutoff was 31.7 mo (23.1-37.1) in C4 and 35.5 mo (22.9-37.3) in C5. In C4, confirmed ORR was 12.3% (95% CI 6.1-21.5) (2 CRs, 8 PRs); median (range) DOR was 8.1 mo (2.5+ to 15.2), and 62.5% had a response ≥6 mo (Kaplan-Meier estimate). Additional efficacy analyses are outlined in the table. A total of 27.2% and 28.9% of pts in C4 and C5, respectively, experienced grade ≥3 treatment-related adverse events. Two pts in C4 died of immune-related AEs (Miller Fisher syndrome and myasthenia gravis). Incidence of any-grade (34.1%) and grade 3 or 4 (5.6%) rash, regardless of relatedness to treatment, was higher than previously reported for individual agents but manageable with standard-of-care treatments; 2 pts discontinued because of rash. Conclusions: After an additional 1 year of follow-up, pembro + enza continued to show antitumor activity and a manageable safety profile in pts with mCRPC who became resistant to enza. The treatment combination is being further evaluated in the ongoing phase 3 KEYNOTE-641 trial (NCT03834493). Clinical trial information: NCT02787005. [Table: see text]

Pembrolizumab (pembro) versus investigator’s choice of paclitaxel, docetaxel, or vinflunine in recurrent, advanced urothelial cancer (UC): 5-year follow-up from the phase 3 KEYNOTE-045 trial

4532

Background: Pembro was approved for the treatment of locally advanced or metastatic UC that progressed during or after a platinum-containing regimen, based on the phase 3 KEYNOTE-045 (NCT02256436) trial that showed significantly improved OS with use of pembro. Updated results are presented from KEYNOTE-045 after >5 y of follow-up since the last patient (pt) was randomized. Methods: KEYNOTE-045 is a randomized, multisite, open-label, phase 3 trial. Pts with histologically or cytologically confirmed UC, progression after platinum-containing chemo, ECOG PS 0-2, measurable disease per RECIST v1.1, and ≤2 prior lines of systemic therapy were eligible. Pts were randomly assigned 1:1 to receive pembro 200 mg Q3W or investigator’s choice of paclitaxel 175 mg/m2 Q3W, docetaxel 75 mg/m2 Q3W, or vinflunine 320 mg/m2 Q3W. Primary end points are PFS (RECIST v1.1, blinded central review) and OS. ORR and duration of response (DOR) were key secondary end points. Results: As of Oct 1, 2020, among 542 enrolled pts, median time from randomization to data cutoff was 62.9 mo (range 58.6-70.9). 9.4% and 0% of pts in the pembro and chemo arms, respectively, completed 2 years of therapy. Median OS was longer for pembro vs chemo (10.1 vs 7.2 mo; HR, 0.71 [95% CI, 0.59-0.86]) overall and in pts with CPS ≥10 (8.0 vs 4.9 mo; HR, 0.59 [95% CI, 0.40-0.86]). For pts with CR or PR, median OS was not reached and 16.4 (95% CI, 11.3-25.1) mo in the pembro and chemo arms, respectively (Table). OS rates at 48 mo were 16.7% for pembro and 10.1% for chemo; 60-mo OS rates were 14.9% and 8.7%, respectively. OS benefit with pembro vs chemo continued regardless of age, ECOG PS, prior therapy, liver metastases, baseline hemoglobin, time from last chemo, histology, risk factors, and chemo choice. Median DOR for responders was longer for pembro vs chemo (29.7 mo [1.6+ to 60.5+] vs 4.4 mo [1.4+ to 63.1+]), and a greater proportion of responses lasted ≥48 mo (40.9% vs 28.3%, Kaplan-Meier) and ≥60 mo (32.8% vs 28.3%). ORR was higher for pembro vs chemo (21.9% vs 11.0%; difference 10.8% [95% CI, 4.6-17.0]). Fewer pts given pembro vs chemo experienced a treatment-related AE of any grade (62.0% vs 90.6%) or grade ≥3 (16.9% vs 50.2%). Conclusions: After 5 y, pembro maintained clinically meaningful OS benefit vs chemo in pts with locally advanced or metastatic UC that progressed during or after platinum-based chemo. Pts who responded to pembro experienced a durable response (median >2 y). Clinical trial information: NCT02256436 .[Table: see text]

18F-Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) is accurate for high-grade prostate cancer bone staging when compared to bone scintigraphy

INTRODUCTION

In this study, we compared ¹⁸F-FDG-postron emission tomography/computed tomography (PET/CT) and bone scintigraphy accuracies for the detection of bone metastases for primary staging in high-grade prostate cancer (PCa) patients to determine if ¹⁸F-FDG-PET/CT could be used alone as a staging modality.

METHODS

Men with localized high-grade PCa (n=256, Gleason 8-10, International Society of Urological Pathology [ISUP] grades 4 or 5) were imaged with bone scintigraphy and ¹⁸F-FDGPET/CT. We compared on a per-patient basis the accuracy of the two imaging modalities, taking intermodality agreement as the standard of truth (SOT).

RESULTS

¹⁸F-FDG-PET/CT detected at least one bone metastasis in 33 patients compared to only 26 with bone scan. Of the seven false-negative bone scintigraphies, four (57.1%) were solitary metastases (monometastatic), three (42.9%) were oligometastatic (2-4 lesions), and none were plurimetastatic (>4 lesions). Compared to SOT, ¹⁸F-FDG-PET/CT showed higher sensitivity and accuracy than bone scintigraphy (100% vs. 78.8%, and 98.7% vs. 98.2%) for the detection of skeletal lesions.

CONCLUSIONS

¹⁸F-FDG-PET/CT appears similar or better than conventional bone scans to assess for bone metastases in patients newly diagnosed with high-grade PCa. Since intraprostatic FDG-uptake is also a biomarker of failure to radical prostatectomy and that FDG-PET/CT has been shown to be accurate in detecting PCa lymph node metastasis, FDG-PET/CT has the potential to be used as the sole preoperative staging modality in high-grade PCa.

Impact of subsequent therapy on survival in KEYNOTE-361: Pembrolizumab (pembro) plus chemotherapy (chemo) or pembro alone versus chemo as first-line therapy for advanced urothelial carcinoma (UC)

439

Background: The phase III KEYNOTE-361 study examined the efficacy and safety of 1L pembro + chemo or pembro alone vs chemo for pts with advanced UC. The PFS and OS benefit of pembro + chemo vs chemo did not reach statistical significance; no further formal tesing was done. We present an exploratory analysis of OS by subsequent therapy in KEYNOTE-361 (NCT02853305) to assess how 1L and 2L therapy selection affected survival outcomes; no formal comparisons were conducted. Methods: OS was estimated for pts by whether they received subsequent therapy, and by whether subsequent therapy included an anti–PD-(L)1 agent. Results: 351 pts were randomized to pembro + chemo, 307 pts to pembro, and 352 pts to chemo. As of Apr 29, 2020, the median (range) time from randomization to data cutoff was 31.7 (22.0-42.3) mo. 124/351 pts (35%) in the pembro + chemo arm, 126/307 pts (41%) in the pembro arm, and 215/352 pts (61%) in the chemo arm received any subsequent therapy. Similar rates of subsequent therapy (pembro + chemo: 32%; pembro: 43%; chemo: 59%) were observed for pts who experienced progressive disease (PD) by blinded independent central review (BICR). A higher rate of pts (169/352 [48%]) in the chemo arm received subsequent anti–PD-(L)1 therapy than in either the pembro + chemo arm (23/351 [7%]) or pembro arm (14/307 [5%]). Due to the small pt numbers, pts in the pembro + chemo or pembro arms who received subsequent anti−PD-(L)1 were not considered further. This analysis included all pts who received 2L therapy (465/1010 pts [46%]); the rate of 2L therapy was similar in pts with PD by BICR (274/615 [45%]). Chemo agents alone or in combination, specifically carboplatin, cisplatin, docetaxel, doxorubicin, gemcitabine, and paclitaxel, were the most commonly received subsequent therapies for pts who did not receive anti–PD-(L)1 in 2L. Pts who received 1L chemo followed by subsequent anti–PD-(L)1 had longer mOS (19.1 mo [95% CI 16.2-22.2]) than pts with 1L pembro followed by 2L therapy not including an anti−PD-(L)1 agent (16.0 mo [95% CI 11.8-19.2]) (Table). Conclusions: In this exploratory analysis, favorable survival outcomes were observed for pts who received 1L chemo followed by anti–PD-(L)1 compared with pts who received 1L pembro followed by 2L therapy not including an anti–PD-(L)1 agent. These data underline the continued importance of immunotherapy as 2L therapy for advanced UC. Clinical trial information: NCT02853305 . Research Sponsor: Merck & Co., Inc[Table: see text]

Analysis of PFS2 by subsequent therapy in KEYNOTE-361: Pembrolizumab (pembro) plus chemotherapy (chemo) or pembro alone versus chemo as 1L therapy for advanced urothelial carcinoma (UC)

448

Background: 1L pembro + chemo did not show statistically superior PFS and OS vs chemo for pts with advanced UC in the phase III KEYNOTE-361 study; OS for pembro vs chemo was not formally tested. We analyzed PFS2 (time from randomization to progressive disease [PD] on first subsequent therapy, or death from any cause, whichever occurs first) by study treatment and subsequent therapy in KEYNOTE-361 (NCT02853305) to determine the effects, if any, of therapy sequence on PFS2. Methods: PFS2 was estimated for pts in each treatment arm, who received any subsequent therapy including any anti–PD-(L)1, any therapy other than anti–PD-(L)1, or no therapy. These were exploratory analyses; no formal comparisons were done. Results: 1010 pts were randomized: 351 pts to receive pembro + chemo, 307 to pembro, and 352 to chemo. As of Apr 29, 2020, the median (range) time from randomization to data cutoff was 31.7 (22.0-42.3) mo. Subsequent therapy was received by 124/351 (35%), 126/307 (41%), and 215/352 (61%) pts in the pembro + chemo, pembro, and chemo arms, respectively. Subsequent anti–PD-(L)1 therapy was received by 169/352 (48%) pts in the chemo arm vs 23/351 (7%) in the pembro + chemo arm and 14/307 (5%) in the pembro arm. Of pts in the pembro arm who received subsequent therapy, >90% received 2L cisplatin-based or carboplatin-based treatment. Median (m) PFS2 (95% CI) for all pts by treatment arm was 14.1 mo (12.6-16.2) with pembro + chemo, 10.9 mo (9.5-12.9) with pembro, and 10.4 mo (9.8-11.2) with chemo. Across treatment arms, pts in the pembro + chemo arm had the longest mPFS2 with any subsequent therapy (14.5 mo [95% CI 13.1-16.6]) (Table). Pts in the pembro arm who received no subsequent therapy had a longer mPFS2 (12.9 mo [95% CI 8.1-17.9]) vs pts in the chemo arm who received no subsequent therapy (9.4 mo [95% CI 7.6-10.6]). Finally, pts treated with 1L pembro in the trial followed by 2L therapy other than anti−PD-(L)1 had comparable mPFS2 (10.2 mo [95% CI 8.6-12.1]) to pts treated with 1L chemo in the trial followed by 2L anti−PD-(L)1 (11.1 mo [95% CI 10.2-12.9]). Conclusions: In this exploratory analysis, treatment sequence of chemo followed by anti−PD-(L)1 upon PD vs anti–PD-(L)1 followed by chemo upon PD did not appear to impact mPFS2. Among pts who did not receive 2L therapy, 1L pembro appeared to be associated with longer mPFS2 than chemo, potentially driven by long-term responders to pembro. Clinical trial information: NCT02853305 . [Table: see text]

1L pembrolizumab (pembro) versus chemotherapy (chemo) for choice-of-carboplatin patients with advanced urothelial carcinoma (UC) in KEYNOTE-361

450

Background: 1L pembro is approved in advanced UC for cisplatin-ineligible pts with PD-L1 combined positive score (CPS) ≥10 and any platinum-ineligible pts regardless of CPS in the United States based on single-arm trial data. In the phase III KEYNOTE-361 study, 1L pembro + chemo did not statistically significantly improve PFS or OS vs chemo for pts with advanced UC; formal testing of 1L pembro vs chemo was not performed. We present an exploratory analysis of outcomes with pembro vs chemo for choice-of-carboplatin (carbo) pts in KEYNOTE-361 (NCT02853305). Methods: At randomization, choice of platinum agent (cisplatin or carbo) plus gemcitabine for each pt was selected based on investigator’s assessment of cisplatin ineligibility. ORR/DOR per RECIST v1.1 by blinded independent central review and OS were determined for all pts selected for carbo (“choice-of-carbo”) and also choice-of-carbo pts with CPS ≥10. Risk difference assessment for select AEs for pembro vs chemo was conducted in choice-of-carbo pts who received ≥1 dose study treatment. Results: As of Apr 29, 2020, the median (range) time from randomization to data cutoff in the full study cohort was 31.7 (22.0-42.3) mo. At randomization, renal impairment was the most common reason for choice of carbo by investigators (36% of all pts). 170 choice-of-carbo pts were randomized to the pembro arm, and 196 choice-of-carbo pts to the chemo arm. Median OS in this subgroup was 14.6 mo with pembro vs 12.3 mo with chemo (HR 0.83 [95% CI 0.65-1.06]). 18-mo OS rate was 42% with pembro vs 40% with chemo. ORR to pembro vs chemo was 27.6% vs 41.8%. Median (range) DOR with pembro vs chemo was not reached (NR) (3.2+-36.1+ mo) vs 6.3 (1.8+-33.8+) mo. 84/170 (49%) and 89/196 (45%) choice-of-carbo pts in the pembro and chemo arms, respectively, had CPS ≥10. In this subgroup, median OS was 15.6 mo with pembro vs 13.5 mo with chemo (HR 0.82 [95% CI 0.57-1.17]). 18-mo OS rate was 44% with pembro vs 43% with chemo. ORR to pembro vs chemo was 29.8% vs 46.1%. Median (range) DOR with pembro vs chemo was NR (4.2-36.1+ mo) vs 8.3 (2.1+-33.8+) mo. Among treated pts (N=166 for pembro, N=190 for chemo), 112 pts (68%) in the pembro arm and 163 pts (86%) in the chemo arm had grade 3-5 AEs of any cause. Pembro was associated with a higher risk of pruritus, while chemo was associated with a higher risk of decreased white blood cell, neutrophil, and platelet counts, nausea, thrombocytopenia, neutropenia, and anemia. Conclusions: Due to the trial design, this subset was not statistically tested and is exploratory. Median OS and 18-mo OS rates did not appear markedly different in the two arms; some parameters such as DOR favored pembro, although longer follow-up is needed to determine median DOR for pembro. The PD-L1 CPS ≥10 did not clearly enrich for responders to pembro in choice-of-carbo pts. Pembro was associated with a lower rate of grade 3-5 AEs of any cause than chemo. Clinical trial information: NCT02853305.

Post-hoc analysis of long-term outcomes in patients with CR, PR, or SD to pembrolizumab (pembro) or platinum-based chemotherapy (chemo) as 1L therapy for advanced urothelial carcinoma (UC) in KEYNOTE-361

435

Background: The phase III KEYNOTE-361 study compared efficacy and safety of 1L pembro + chemo or pembro vs chemo in pts with advanced UC. The trial did not meet its primary endpoints of PFS or OS superiority for pembro + chemo vs chemo; formal testing for OS for pembro vs chemo was not performed. We present a post hoc landmark analysis to examine the durability of CR/PR/SD and long-term survival in pts with CR, PR, or SD to pembro vs chemo at week 9 in KEYNOTE-361 (NCT02853305). Methods: Landmark analyses of OS by CR/PR/SD at 9 weeks after randomization in the ITT population were performed. Pts were included if they had a best response of CR/PR/SD per RECIST v1.1 by blinded independent central review at the landmark date of week 9 (first imaging assessment per study protocol). Duration of CR/PR/SD and OS were estimated by the Kaplan-Meier method. No formal comparisons were performed. Results: 307 pts were randomized to receive pembro and 352 pts to receive chemo in the KEYNOTE-361 study. As of Apr 29, 2020, the median (range) time from randomization to data cutoff was 32.5 (22.0-42.4) mo for the pembo arm and 31.4 (22.1-41.6) mo for the chemo arm. In the landmark analysis, fewer pts had CR/PR/SD at week 9 with pembro (n=137 [45%]) than with chemo (n=253 [72%]). Median (range) duration of response for pembro vs chemo was 18.7 (4.4+-35.4+) vs 12.3 (0.0+-29.7+) mo for pts with CR, and 35.0 (1.1-36.1+) vs 6.1 (0.0+-36.3+) mo for pts with PR. Median (range) duration of SD was 4.8 mo (0.0-38.2+) with pembro and 4.6 mo (0.0-16.1+) with chemo. Median OS (95% CI) for pembro vs chemo was not reached (NR) (25.5-NR) vs NR (19.1-NR) for pts with CR; NR (NR-NR) vs 14.8 mo (12.1-21.0) for pts with PR; and 18.5 mo (13.8-28.8) vs 11.1 mo (8.1-14.6) for pts with SD, respectively. Long-term OS rates were higher with pembro vs chemo across all groups (CR/PR/SD) at week 9 (Table). Conclusions: In this post hoc landmark analysis, chemo was associated with more initial responses than pembro, whereas pembro was associated with longer median duration of CR and PR, and generally longer median OS than chemo. Among pts who achieved CR/PR/SD at week 9, the relative OS benefit for pembro vs chemo increased over time. Clinical trial information: NCT02853305. [Table: see text]

Long chain omega-3 fatty acids and their oxidized metabolites are associated with reduced prostate tumor growth

INTRODUCTION

Cancer has been associated with increased oxidative stress and deregulation of bioactive oxylipins derived from long-chain polyunsaturated fatty acids (LC-PUFA) like arachidonic acid (AA). There is a debate whether ω-3 LC-PUFA could promote or prevent prostate tumor growth through immune modulation and reduction of oxidative stress. Our aim was to study the association between enzymatically or non-enzymatically produced oxidized-LC-PUFA metabolites and tumor growth in an immune-competent eugonadal and castrated C57BL/6 male mice injected with TRAMP-C2 prostate tumor cells, fed with ω-3 or ω-6 LC-PUFA-rich diets.

MATERIALS AND METHODS

Tumor fatty acids were profiled by gas chromatography and 26 metabolites derived from either AA, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were assessed by liquid chromatography-mass spectrometry.

RESULTS

The enriched ω-3 diet did not reduce oxidative stress overall in tumors but favored the formation of ω-3 rather than ω-6 derived isoprostanoids. We discovered that EPA and its oxidized-derivatives like F₃-isoprostanes and prostaglandin (PG)F_3α, were inversely correlated with tumor volume (spearman correlations and T-test, p<0.05). In contrast, F₂-isoprostanes, adrenic acid, docosapentaenoic acid (DPA_ω-6) and PGE₂ were positively correlated with tumor volume. Interestingly, F₄-neuroprostanes, PGD₂, PGF_2α, and thromboxane were specifically increased in TRAMP-C2 tumors of castrated mice compared to those of eugonadal mice.

DISCUSSION

Decreasing tumor growth under ω-3 diet could be attributed in part to increased levels of EPA and its oxidized-derivatives, a reduced level of pro-angiogenic PGE₂ and increased levels of F₄-neuroprostanes and resolvins content in tumors, suspected of having anti-proliferative and anti-inflammatory effects.

Identification of a Transcriptomic Prognostic Signature by Machine Learning Using a Combination of Small Cohorts of Prostate Cancer

Determining which treatment to provide to men with prostate cancer (PCa) is a major challenge for clinicians. Currently, the clinical risk-stratification for PCa is based on clinico-pathological variables such as Gleason grade, stage and prostate specific antigen (PSA) levels. But transcriptomic data have the potential to enable the development of more precise approaches to predict evolution of the disease. However, high quality RNA sequencing (RNA-seq) datasets along with clinical data with long follow-up allowing discovery of biochemical recurrence (BCR) biomarkers are small and rare. In this study, we propose a machine learning approach that is robust to batch effect and enables the discovery of highly predictive signatures despite using small datasets. Gene expression data were extracted from three RNA-Seq datasets cumulating a total of 171 PCa patients. Data were re-analyzed using a unique pipeline to ensure uniformity. Using a machine learning approach, a total of 14 classifiers were tested with various parameters to identify the best model and gene signature to predict BCR. Using a random forest model, we have identified a signature composed of only three genes (JUN, HES4, PPDPF) predicting BCR with better accuracy [74.2%, balanced error rate (BER) = 27%] than the clinico-pathological variables (69.2%, BER = 32%) currently in use to predict PCa evolution. This score is in the range of the studies that predicted BCR in single-cohort with a higher number of patients. We showed that it is possible to merge and analyze different small and heterogeneous datasets altogether to obtain a better signature than if they were analyzed individually, thus reducing the need for very large cohorts. This study demonstrates the feasibility to regroup different small datasets in one larger to identify a predictive genomic signature that would benefit PCa patients.

Omega-3 Eicosapentaenoic Acid Reduces Prostate Tumor Vascularity

The impact of omega (ω)-3 fatty acids on prostate cancer is controversial in epidemiological studies but experimental studies suggest a protective effect. However, little is known about the mechanism of action. Here, we studied the effects of purified fatty acid molecules on prostate tumor progression using the TRAMP-C2 syngeneic immunocompetent mouse model. Compared with ω-6 or ω-9-supplemented animals, we observed that late-stage prostate tumor growth was reduced with a monoacylglyceride (MAG)-conjugated form of eicosapentaenoic acid (EPA) supplementation, whereas docosahexanenoic acid (DHA) caused an early reduction. MAG-EPA significantly decreased tumor blood vessel diameter (P < 0.001). RNA sequencing analysis revealed that MAG-EPA downregulated angiogenesis- and vascular-related pathways in tumors. We also observed this tissue vascular phenotype in a clinical trial testing MAG-EPA versus a high oleic sunflower oil placebo. Using anti-CD31 IHC, we observed that MAG-EPA reduced blood vessel diameter in prostate tumor tissue (P = 0.03) but not in normal adjacent tissue. Finally, testing autocrine and paracrine effects in an avascular tumor spheroid growth assay, both exogenous MAG-EPA and endogenous ω3 reduced VEGF secretion and in vitro endothelial cell tube formation and blocked tumor spheroid growth, suggesting that ω3 molecules can directly hinder prostate cancer cell growth. Altogether, our results suggest that fatty acids regulate prostate cancer growth and that a tumor-specific microenvironment is required for the anti-vascular effect of MAG-EPA in patients with prostate cancer. IMPLICATIONS: Increasing the amount of ingested EPA omega-3 subtype for patients with prostate cancer might help to reduce prostate tumor progression by reducing tumor vascularization.

Immune-focused multi-omics analysis of prostate cancer: leukocyte Ig-Like receptors are associated with disease progression

Prostate cancer (PCa) immunotherapy has shown limited efficacy so far, even in advanced-stage cancers. The success rate of PCa immunotherapy might be improved by approaches more adapted to the immunobiology of the disease. The objective of this study was to perform a multi-omics analysis to identify immune genes associated with PCa progression to better characterize PCa immunobiology and propose new immunotherapeutic targets. mRNA, miRNA, methylation, copy number aberration, and single nucleotide variant datasets from The Cancer Genome Atlas PRAD cohort were analyzed after filtering for genes associated with immunity. Sparse partial least squares-discriminant analyses were performed to identify features associated with biochemical recurrence (BCR) in each type of omics data. Selected features predicted BCR with a balanced error rate (BER) of 0.20 to 0.51 in single-omics and of 0.05 in multi-omics analyses. Amongst features associated with BCR were genes from the Immunoglobulin Ig-like Receptor (LILR) family which are immune checkpoints with immunotherapeutic potential. Using Multivariate INTegrative (MINT) analysis, the association of five LILR genes with BCR was quantified in a combination of three RNA-seq datasets and confirmed with Kaplan-Meier analysis in both these and in an independent RNA-seq dataset. Finally, immunohistochemistry showed that a high number of LILRB1 positive cells within the tumors predicted long-term adverse outcomes. Thus, tumors characterized by abnormal expression of LILR genes have an elevated risk of recurring after definitive local therapy. The immunotherapeutic potential of these regulators to stimulate the immune response against PCa should be evaluated in pre-clinical models.

Building a Canadian Translational Bladder Cancer Research Network

Bladder cancer research has historically lagged behind efforts in other disease sites with substantial underfunding relative to the heavy morbidity and mortality suffered by patients. Alongside increasing advocacy however, more recent advances in our understanding of the molecular biology of bladder cancer has ushered in a period of renaissance with exciting prospects for novel, precise diagnostics and therapeutics. Given significant and diverse assets within the research community across Canada, an inaugural translational research forum was convened to identify research gaps and strengths, and to formalize investigational themes that would be apposite for multi-institutional collaboration. The virtual meeting brought together a multi-disciplinary network of genitourinary cancer researchers, including clinicians and basic scientists, and entailed detailed environmental scans of the Canadian clinical and translational research landscape as well as selected “elevator pitches” of potential research themes. The results of these discussions are detailed herein and have provided the impetus to formalize the Canadian Bladder Cancer Research Network (CBCRN). Working groups have been created to focus future multi-institutional collaborations in four inter-related initiatives: biomarker development, epigenetic targeting, immuno-oncology and the microbiome.

A prospective, multisite study analyzing the percentage of urological cases that can be completely managed by telemedicine

INTRODUCTION

The COVID-19 pandemic has accelerated the development of telemedicine due to confinement measures. However, the percentage of outpatient urological cases that could be managed completely by telemedicine outside of the COVID-19 pandemic remains to be determined. We conducted a prospective, multisite study involving all urologists working in the region of Quebec City.

METHODS

During the first four weeks of the regional confinement, 18 pediatric and adult urologists were asked to determine, after each telemedicine appointment, if it translated into a complete (CCM), incomplete (ICM), or suboptimal case management (SCM, adequate only in the context of the pandemic).

RESULTS

A total of 1679 appointments representing all urological areas were registered. Overall, 67.6% (95% confidence interval [CI] 65.3; 69.8), 27.1% (25.0; 29.3), and 4.3% (3.5; 5.4) were reported as CCM, SCM, and ICM, respectively. The CCM ratio varied according to the reason for consultation, with cancer suspicion (52.9% [42.9; 62.8]) and pediatric reasons (38.0% [30.0; 46.6]) showing the lowest CCM percentages. CCM percentages also varied significantly based on the setting where it was performed, ranging from 61.1% (private clinic) to 86.8% (endourology and general hospital).

CONCLUSIONS

We show that two-thirds of all urological outpatient cases could be completely managed by telemedicine outside of the pandemic. After the pandemic, it will be important to incorporate telemedicine as an alternative for a patient's first or followup visit, especially those with geographical, pathological, and socioeconomic considerations.