Sir Peter MacCallum Department of Oncology - Research Publications
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ItemNo Preview AvailableAberrations in circulating ceramide levels are associated with poor clinical outcomes across localised and metastatic prostate cancer(SPRINGERNATURE, 2021-09)BACKGROUND: Dysregulated lipid metabolism is associated with more aggressive pathology and poorer prognosis in prostate cancer (PC). The primary aim of the study is to assess the relationship between the plasma lipidome and clinical outcomes in localised and metastatic PC. The secondary aim is to validate a prognostic circulating 3-lipid signature specific to metastatic castration-resistant PC (mCRPC). PATIENTS AND METHODS: Comprehensive lipidomic analysis was performed on pre-treatment plasma samples from men with localised PC (N = 389), metastatic hormone-sensitive PC (mHSPC)(N = 44), or mCRPC (validation cohort, N = 137). Clinical outcomes from our previously published mCRPC cohort (N = 159) that was used to derive the prognostic circulating 3-lipid signature, were updated. Associations between circulating lipids and clinical outcomes were examined by Cox regression and latent class analysis. RESULTS: Circulating lipid profiles featuring elevated levels of ceramide species were associated with metastatic relapse in localised PC (HR 5.80, 95% CI 3.04-11.1, P = 1 × 10-6), earlier testosterone suppression failure in mHSPC (HR 3.70, 95% CI 1.37-10.0, P = 0.01), and shorter overall survival in mCRPC (HR 2.54, 95% CI 1.73-3.72, P = 1 × 10-6). The prognostic significance of circulating lipid profiles in localised PC was independent of standard clinicopathological and metabolic factors (P < 0.0002). The 3-lipid signature was verified in the mCRPC validation cohort (HR 2.39, 95% CI 1.63-3.51, P = 1 × 10-5). CONCLUSIONS: Elevated circulating ceramide species are associated with poorer clinical outcomes across the natural history of PC. These clinically actionable lipid profiles could be therapeutically targeted in prospective clinical trials to potentially improve PC outcomes.
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ItemPHASE 1/2 STUDY OF THOR-707 (SAR444245), A PEGYLATED RECOMBINANT NON-ALPHA IL-2, AS MONOTHERAPY AND IN COMBINATION WITH PEMBROLIZUMAB OR CETUXIMAB IN PATIENTS (PTS) WITH ADVANCED SOLID TUMORS(BMJ PUBLISHING GROUP, 2021-11)Background THOR-707 (SAR444245) is a recombinant human IL-2 molecule irreversibly bound to a PEG chain to block alpha-binding while retaining near-native affinity for beta/gamma IL-2 receptor subunits. We report updated results from the ongoing HAMMER phase 1/2 trial. Methods SAR444245 was given via IV infusion as monotherapy Q2W [A] or Q3W [B], with pembrolizumab 200mg IV Q3W [C], or Q3W with cetuximab 400mg/m2 IV on D1 then 250mg/m2 IV QW [D] after pre-medication and peri-infusion hydration. A 3+3 design was used to identify the MTD/RP2D in pts with advanced solid tumors. Key objectives included assessments of safety, efficacy, pharmacokinetics (PK) and pharmacodynamics (PD). Results 68 pts, median age 61.5 (37–78) yrs with median 3 (1–10) prior therapies enrolled. Most common tumors: melanoma (n=10), colorectal (n=11). Doses tested by cohort: [A]: 8–16 µg/kg (n=9); [B]: 8–40 µg/kg (n=29); [C]: 8–32 µg/kg (n=20); [D]: 16–24 µg/kg (n=10). The most common (>30%) AEs included pyrexia (52.5%), nausea (50.0%), flu-like symptoms (44.1%), vomiting (36.8%), chills (32.4%), fatigue (32.4%), AST elevation (30.9%). AEs generally resolved promptly with supportive care. Grade(G) 3/4 (>5%) related AEs included ALT/AST elevation (5.9%), and decreased lymphocyte count (26.5% within first 24 hrs, recovering by 48–72 hrs, this lymphocyte migration is mechanistically consistent with immune cell margination). G3/4 CRS was observed in 2 pts. Two DLTs occurred: G3 infusion reaction (32 µg/kg [B]) and G3 AST/ALT/G2 bilirubin elevation with G2 CRS (24 µg/kg [C]). No vascular leak syndrome, QTc prolongation, cardiac, or end organ toxicity was observed. Half-life was ~10 h. Sustained increases in CD8 T and NK cells were observed (fold relative to baseline): monotherapy (1–9.4x and 2–43.3x); with pembrolizumab (0.5–5.78x and 1.5–26.9x); with cetuximab (1.3–7.57x and 3.6–45.4x). Max CD4 and eosinophils increased to 136 cell/µL and 1078 cell/µL. No IL-5 elevation or ADAs were observed. Transient IL-6 increases in 4 pts (500, 627, 1000, 1100 pg/mL) were not associated with AEs. Four pts had confirmed PRs (1 PD1-treated SCC, unknown primary [B]; 2 PD1-naïve BCC and 1 PD1-treated HNSCC [C]); 3 pts had minor responses -- prostate (-24%) and PD1-treated melanoma (-17%) [B]; PD1-treated NSCLC (¬-29%) [C] -- after ≥2 scans. 23 pts completed ≥5 cycles. Conclusions SAR444245 was well tolerated and demonstrated antitumor activity in heavily pretreated patients, including prior checkpoint inhibitor therapy. Clinical safety, efficacy and PD suggest a wide therapeutic window. Combination with pembrolizumab and cetuximab leveraged SAR44245’s effects on CD8 T and NK cells. Trial Registration NCT04009681 Ethics Approval The clinical trial was approved by each institutions ethics’ and review board prior to beginning study enrollment.
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ItemRelationship between Circulating Lipids and Cytokines in Metastatic Castration-Resistant Prostate Cancer(MDPI, 2021-10)Circulating lipids or cytokines are associated with prognosis in metastatic castration-resistant prostate cancer (mCRPC). This study aimed to understand the interactions between lipid metabolism and immune response in mCRPC by investigating the relationship between the plasma lipidome and cytokines. Plasma samples from two independent cohorts of men with mCRPC (n = 146, 139) having life-prolonging treatments were subjected to lipidomic and cytokine profiling (290, 763 lipids; 40 cytokines). Higher baseline levels of sphingolipids, including ceramides, were consistently associated with shorter overall survival in both cohorts, whereas the associations of cytokines with overall survival were inconsistent. Increasing levels of IL6, IL8, CXCL16, MPIF1, and YKL40 correlated with increasing levels of ceramide in both cohorts. Men with a poor prognostic 3-lipid signature at baseline had a shorter time to radiographic progression (poorer treatment response) if their lipid profile at progression was similar to that at baseline, or their cytokine profile at progression differed to that at baseline. In conclusion, baseline levels of circulating lipids were more consistent as prognostic biomarkers than cytokines. The correlation between circulating ceramides and cytokines suggests the regulation of immune responses by ceramides. The association of treatment response with the change in lipid profiles warrants further research into metabolic interventions.
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ItemOvercoming enzalutamide resistance in metastatic prostate cancer by targeting sphingosine kinase(ELSEVIER, 2021-10)BACKGROUND: Intrinsic resistance to androgen receptor signalling inhibitors (ARSI) occurs in 20-30% of men with metastatic castration-resistant prostate cancer (mCRPC). Ceramide metabolism may have a role in ARSI resistance. Our study's aim is to investigate the association of the ceramide-sphingosine-1-phosphate (ceramide-S1P) signalling axis with ARSI resistance in mCRPC. METHODS: Lipidomic analysis (∼700 lipids) was performed on plasma collected from 132 men with mCRPC, before commencing enzalutamide or abiraterone. AR gene aberrations in 77 of these men were identified by deep sequencing of circulating tumour DNA. Associations between circulating lipids, radiological progression-free survival (rPFS) and overall survival (OS) were examined by Cox regression. Inhibition of ceramide-S1P signalling with sphingosine kinase (SPHK) inhibitors (PF-543 and ABC294640) on enzalutamide efficacy was investigated with in vitro assays, and transcriptomic and lipidomic analyses of prostate cancer (PC) cell lines (LNCaP, C42B, 22Rv1). FINDINGS: Men with elevated circulating ceramide levels had shorter rPFS (HR=2·3, 95% CI=1·5-3·6, p = 0·0004) and shorter OS (HR=2·3, 95% CI=1·4-36, p = 0·0005). The combined presence of an AR aberration with elevated ceramide levels conferred a worse prognosis than the presence of only one or none of these characteristics (median rPFS time = 3·9 vs 8·3 vs 17·7 months; median OS time = 8·9 vs 19·8 vs 34·4 months). SPHK inhibitors enhanced enzalutamide efficacy in PC cell lines. Transcriptomic and lipidomic analyses indicated that enzalutamide combined with SPHK inhibition enhanced PC cell death by SREBP-induced lipotoxicity. INTERPRETATION: Ceramide-S1P signalling promotes ARSI resistance, which can be reversed with SPHK inhibitors. FUNDING: None.
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ItemCurrent treatment options for newly diagnosed metastatic hormone-sensitive prostate cancer-a narrative review(AME PUBL CO, 2021-10)Prostate cancer continues to be one of the most commonly diagnosed cancers in men globally and a leading cause of male cancer deaths. The landscape of metastatic hormone-sensitive prostate cancer has significantly changed over the past decade. For many years, androgen deprivation therapy alone through surgical or chemical castration was the mainstay of treatment yielding limited 5-year survival rates. New treatment approaches using Docetaxel chemotherapy or androgen receptor pathway inhibitors to intensify upfront systemic therapy have resulted in significantly improved survival rates compared to androgen deprivation therapy alone. Clinicians are now equipped with an arsenal of drugs capable of prolonging life for metastatic hormone-sensitive prostate cancer patients. Furthermore, new treatment modalities are being tested in clinical trials making treatment of metastatic hormone-sensitive prostate cancer an extremely dynamic space. In this narrative review, we provide an overview of the key systemic treatments for metastatic hormone-sensitive prostate cancer, namely androgen deprivation therapy, novel androgen receptor pathway inhibitors and Docetaxel. We summarise a series of landmark trials that have led to the integration of novel androgen receptor pathway inhibitors and docetaxel into the treatment paradigm for metastatic hormone-sensitive prostate cancer. Lastly, we discuss nursing, financial and side-effect considerations pertaining to the use of these drugs. This article aims to give its readers an understanding of the evidence and clinical aspects of novel therapies in metastatic hormone-sensitive prostate cancer as they become increasingly available for use around the world.
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ItemClinical Effectiveness of Second-line Sunitinib Following Immuno-oncology Therapy in Patients with Metastatic Renal Cell Carcinoma: A Real-world Study(CIG MEDIA GROUP, LP, 2021-08)BACKGROUND: Limited data exist on the clinical effectiveness of second-line (2L) vascular endothelial growth factor (receptor) targeted inhibitor (VEGF(R)i) sunitinib after first-line (1L) immuno-oncology (IO) therapy for patients with metastatic renal cell carcinoma (mRCC) in real-world settings. METHODS: A retrospective cohort study among adult patients with mRCC treated with 2L sunitinib following 1L IO was conducted from select International mRCC Database Consortium (IMDC) centers. All analyses were performed overall and by 1L ipilimumab + nivolumab (IPI+NIVO) or 1L IO+VEGF(R)i. Median overall survival (mOS) and time-to-treatment discontinuation (mTTD) in 2L were estimated using Kaplan-Meier analysis. The 2L objective response rate (ORR) (complete/partial response) was reported. RESULTS: Among 102 patients on 2L sunitinib, mean age was 61.3 years. IMDC risk scores at 2L initiation was available for 83 patients: 8 (9.6%) were favorable, 45 (54.2%) were intermediate, and 30 (36.1%) were poor risk. The 1L consisted of IPI+NIVO in 62 (60.8%), IO+VEGF(R)i therapy in 27 (26.5%), and IO monotherapy in 13 (12.7%) patients. Among all patients, mOS was 15.6 months (95% confidence interval [CI], 9.8-21.7), with a 1-year OS rate of 57.5% (95% CI, 45.2-68.0). mTTD was 5.4 months (95% CI, 4.2-7.2) and ORR was 22.5%. CONCLUSION: Despite availability of effective 1L therapies in recent years, 2L sunitinib continues to have clinical activity after failure of 1L IO. Further studies on optimal treatment sequencing after 1L IO progression are needed.
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ItemThe MURAL collection of prostate cancer patient-derived xenografts enables discovery through preclinical models of uro-oncology(NATURE PORTFOLIO, 2021-08-19)Preclinical testing is a crucial step in evaluating cancer therapeutics. We aimed to establish a significant resource of patient-derived xenografts (PDXs) of prostate cancer for rapid and systematic evaluation of candidate therapies. The PDX collection comprises 59 tumors collected from 30 patients between 2012-2020, coinciding with availability of abiraterone and enzalutamide. The PDXs represent the clinico-pathological and genomic spectrum of prostate cancer, from treatment-naïve primary tumors to castration-resistant metastases. Inter- and intra-tumor heterogeneity in adenocarcinoma and neuroendocrine phenotypes is evident from bulk and single-cell RNA sequencing data. Organoids can be cultured from PDXs, providing further capabilities for preclinical studies. Using a 1 x 1 x 1 design, we rapidly identify tumors with exceptional responses to combination treatments. To govern the distribution of PDXs, we formed the Melbourne Urological Research Alliance (MURAL). This PDX collection is a substantial resource, expanding the capacity to test and prioritize effective treatments for prospective clinical trials in prostate cancer.
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ItemAndrogens alter the heterogeneity of small extracellular vesicles and the small RNA cargo in prostate cancer(WILEY, 2021-08)Proliferation and survival of prostate cancer cells are driven by the androgen receptor (AR) upon binding to androgen steroid hormones. Manipulating the AR signalling axis is the focus for prostate cancer therapy; thus, it is crucial to understand the role of androgens and AR on extracellular vesicle (EV) secretion and cargo. In this study, we report that plasma-derived circulating vesicles consisting of CD9 and double-positive for CD9 and Prostate Specific Membrane Antigen (PSMA) are increased in patients with advanced metastatic prostate cancer, whereas double positives for CD9 and CD63 small extracellular vesicles (S-EVs) are significantly higher in patients with localised prostate cancer. Androgen manipulation by dihydrotestosterone (DHT) and the clinical antagonist enzalutamide (ENZ) altered the heterogeneity and size of CD9 positive S-EVs in AR expressing prostate cancer cells, while assessment of the total number and protein cargo of total S-EVs was unaltered across different treatment groups. Furthermore, hormone stimulation caused strong and specific effects on the small RNA cargo of S-EVs. A total of 543 small RNAs were found to be regulated by androgens including miR-19-3p and miR-361-5p. Analysis of S-EVs heterogeneity and small RNA cargo may provide clinical utility for prostate cancer and be informative to understand further the mechanism of resistance to androgen targeted therapy in castration-resistant prostate cancer.
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ItemNo Preview AvailablePreclinical Evidence of the Efficacy of Lewis Y Car T Cells in Patient-Derived Models of Prostate Cancer(The Endocrine Society, 2021-05-03)Abstract Chimeric antigen receptor T (CAR T) cell therapy is an adoptive immunotherapy that has led to new treatments for lymphoma, leukemia, and other blood cancers; however, its efficacy for prostate cancer remains unproven. Here we report pre-clinical evidence of the efficacy of CAR T cell therapy against the Lewis Y antigen (LeY) using patient-derived models of prostate cancer. To assess the expression of LeY on prostate tumours, we performed immunohistochemistry on a cohort of 41 patient-derived xenografts (PDXs). Cytoplasmic and membrane expression were separately assessed and quantified, for each patient. Overall, 61% (25/41) of PDXs were positive for membrane LeY expression, of which 18 PDXs had greater than 50% membrane-positive cells, and considered most suitable to detection and stable binding by anti-LeY CAR T’s. To determine the in vitro sensitivity to CAR T cytotoxicity, we selected 4 PDXs with high and 2 PDXs with low LeY expression using 3 androgen receptor (AR)-positive adenocarcinomas and 3 AR-negative tumors expressing neuroendocrine markers. Next we established organoids for in vitro co-culture assays where organoids were co-incubated with an equal number of anti-LeY+ CAR T cells or Empty vector control CAR T cells (Ev CAR T). Using time-lapse microscopy we reported destruction of organoids by LeY+ CAR T cells as indicated by their morphological collapse and uptake of propidium iodide from the culture medium; control Ev CAR T cells produced no cytotoxicity. Over the 48h assay, the level of target cell death of the LeY+ organoids was correlated to the intensity LeY surface expression. Target cell death mediated by the CAR T cells required perforin and granzyme B, as potent and highly specific small molecule inhibitors of perforin (SN34960) and granzyme B (C20) applied alone or in combination greatly decreased PI uptake, indicating organoid survival. Neither inhibitor adversely affected CAR T cell viability as measured by PI and Annexin V staining. This demonstrated canonical activation of granule exocytosis pathway by the CAR T cells, leading to organoid cell death. To assess CAR T cell efficacy in vivo, we selected one PDX with high LeY expression. Monotherapy with CAR T cells failed to decrease tumour volume compared to vehicle control. However, CAR T cells given after a single dose of the chemotherapeutic agent carboplatin greatly and durably reduced tumour burden, with residual tumour mass being less than 1% of their original size (0.56 ± 0.23% of tumour volume at the start of treatment). Overall, these data provide preclinical evidence that: i) high membrane expression of LeY correlates with in vitro and in vivo CAR T cell-induced tumour cell death via the canonical perforin/granzyme B mechanism; and, ii) membrane LeY can be used as a biomarker for patient selection.