John Violet

Protocol for the ProCare Trial: a phase II randomised controlled trial of shared care for follow-up of men with prostate cancer

Introduction Men with prostate cancer require long-term follow-up to monitor disease progression and manage common adverse physical and psychosocial consequences of treatment. There is growing recognition of the potential role of primary care in cancer follow-up. This paper describes the protocol for a phase II multisite randomised controlled trial of a novel model of shared care for the follow-up of men after completing treatment for low-moderate risk prostate cancer. Methods and analysis The intervention is a shared care model of follow-up visits in the first 12 months after completing treatment for prostate cancer with the following specific components: a survivorship care plan, general practitioner (GP) management guidelines, register and recall systems, screening for distress and unmet needs and patient information resources. Eligible men will have completed surgery and/or radiotherapy for low-moderate risk prostate cancer within the previous 8 weeks and have a GP who consents to participate. Ninety men will be randomised to the intervention or current hospital follow-up care. Study outcome measures will be collected at baseline, 3, 6 and 12 months and include anxiety, depression, unmet needs, prostate cancer-specific quality of life and satisfaction with care. Clinical processes and healthcare resource usage will also be measured. The principal emphasis of the analysis will be on obtaining estimates of the treatment effect size and assessing feasibility in order to inform the design of a subsequent phase III trial. Ethics and dissemination Ethics approval has been granted by the University of Western Australia and from all hospital recruitment sites in Western Australia and Victoria. Results of this phase II trial will be reported in peer-reviewed publications and in conference presentations. Trial Registration Australian New Zealand Clinical Trial Registry ACTRN12610000938000

[177Lu]-PSMA-617 radionuclide treatment in patients with metastatic castration-resistant prostate cancer (LuPSMA trial): a single-centre, single-arm, phase 2 study

BACKGROUND Progressive metastatic castration-resistant prostate cancer is a highly lethal disorder and new effective therapeutic agents that improve patient outcomes are urgently needed. Lutetium-177 [177Lu]-PSMA-617, a radiolabelled small molecule, binds with high affinity to prostate-specific membrane antigen (PSMA) enabling beta particle therapy targeted to metastatic castration-resistant prostate cancer. We aimed to investigate the safety, efficacy, and effect on quality of life of [177Lu]-PSMA-617 in men with metastatic castration-resistant prostate cancer who progressed after standard treatments. METHODS In this single-arm, single-centre, phase 2 trial, we recruited men (aged 18 years and older) with metastatic castration-resistant prostate cancer and progressive disease after standard treatments, including taxane-based chemotherapy and second-generation anti-androgens, from the Peter MacCallum Cancer Centre, Melbourne, VIC, Australia. Patients underwent a screening PSMA and FDG-PET/CT to confirm high PSMA-expression. Eligible patients had progressive disease defined by imaging (according to Response Evaluation Criteria In Solid Tumours [RECIST] or bone scan) or new pain in an area of radiographically evident disease, and were required to have an Eastern Cooperative Oncology Group (ECOG) performance status score of 2 or lower. Eligible patients received up to four cycles of intravenous [177Lu]-PSMA-617, at six weekly intervals. The primary endpoint was PSA response according to Prostate Cancer Clinical Trial Working Group criteria defined as a greater than 50% PSA decline from baseline and toxicity according to CTCAE. Additional primary endpoints were imaging responses (as measured by bone scan, CT, PSMA, and FDG PET/CT) and quality of life (assessed with the EORTC-Q30 and Brief Pain Inventory-Short Form questionnaires), all measured up to 3 months post completion of treatment. This trial is registered with the Australian New Zealand Clinical Trials Registry, number 12615000912583. FINDINGS Between Aug 26, 2015, and Dec 8, 2016, 43 men were screened to identify 30 patients eligible for treatment. 26 (87%) had received at least one line of previous chemotherapy (80% docetaxel and 47% cabazitaxel) and 25 (83%) received prior abiraterone acetate, enzalutamide, or both. The mean administered radioactivity was 7·5 GBq per cycle. 17 (57%) of 30 patients (95% CI 37-75) achieved a PSA decline of 50% or more. There were no treatment-related deaths. The most common toxic effects related to [177Lu]-PSMA-617 were grade 1 dry mouth recorded in 26 (87%) patients, grade 1 and 2 transient nausea in 15 (50%), and G1-2 fatigue in 15 (50%). Grade 3 or 4 thrombocytopenia possibly attributed to [177Lu]-PSMA-617 occurred in four (13%) patients. Objective response in nodal or visceral disease was reported in 14 (82%) of 17 patients with measurable disease. Clinically meaningful improvements in pain severity and interference scores were recorded at all timepoints. 11 (37%) patients experienced a ten point or more improvement in global health score by the second cycle of treatment. INTERPRETATION Our findings show that radionuclide treatment with [177Lu]-PSMA-617 has high response rates, low toxic effects, and reduction of pain in men with metastatic castration-resistant prostate cancer who have progressed after conventional treatments. This evidence supports the need for randomised controlled trials to further assess efficacy compared with current standards of care. FUNDING None.

Attenuation of Resting but Not Load-Mediated Protein Synthesis in Prostate Cancer Patients on Androgen Deprivation

Context Androgen deprivation therapy (ADT) is a common prostate cancer (PCa) treatment but results in muscular atrophy. Periodic increases in muscle protein synthesis (MPS) that occur after resistance exercise or protein intake may ameliorate this muscle loss, but the impact of these anabolic stimuli during ADT is unclear. Objective To determine the acute MPS response to whey protein supplementation with and without resistance exercise during ADT. Design Acute response in PCa patients vs age-matched controls (CON). Setting Academic laboratory setting. Participants PCa patients on ADT (N = 8) and CON (N = 10). Intervention A standardized diet was consumed for 2 days prior to performing unilateral knee extension resistance exercise followed by ingestion of 40 g of whey protein. Main Outcome Measures Bilateral biopsies and stable isotope infusions were used to determine MPS rates at rest after protein ingestion with and without resistance exercise. Results Baseline MPS during ADT was suppressed relative to CON (P = 0.01). Protein consumption stimulated MPS in both groups (approximate twofold increase, both P < 0.001), but to a greater extent in CON (P = 0.003). Protein plus resistance exercise increased MPS (∼3.4-fold increase, both P < 0.001) to a greater extent than did protein alone (P < 0.001), but with no difference between groups (P = 0.380). Conclusions ADT reduces basal and protein feeding-induced rises in MPS; however, combined protein ingestion with resistance exercise stimulated MPS to a similar degree as CON. Testosterone appears to play a role in maintaining muscle mass but is not necessary to initiate a robust response in MPS following resistance exercise when combined with protein ingestion.

Stereotactic Abative Body Radiotherapy (SABR) for Oligometastatic Prostate Cancer: A Prospective Clinical Trial

BACKGROUND Stereotactic ablative body radiotherapy (SABR) is an emerging treatment option for oligometastatic prostate cancer. However, limited prospective evidence is available. OBJECTIVE To determine the safety and feasibility of single fraction SABR for patients with oligometastatic prostate cancer. Secondary endpoints were local and distant progression-free survival (LPFS and DPFS), toxicity, quality of life (QoL), and prostate-specific antigen response. DESIGN, SETTING, AND PARTICIPANTS In a prospective clinical trial, patients were screened with computed tomography, bone scan, and sodium fluoride positron emission tomography scan and had one to three oligometastases. Kaplan-Meier methods were used to determine LPFS and DPFS. Toxicity was graded using Common Terminology Criteria for Adverse Event version 4.0. QoL was assessed using European Organization for Research and Treatment of Cancer QLQ-C30 and QLQ-BM22 at 1, 3,12, and 24 mo. INTERVENTION A single fraction of 20-Gy SABR to each lesion. RESULTS AND LIMITATIONS Between 2013 and 2014, 33 consecutive patients received SABR to a total of 50 oligometastases and were followed for 2 yr. The median age was 70 yr. The Gleason score was ≥8 in 15 patients (45%). Twenty patients had bone only, 12 had node only, and one had mixed disease. SABR was feasible and delivered as planned in 97% of cases. There was one grade 3 adverse event (3.0%, vertebral fracture). No patient died. The 1 and 2-yr LPFS was 97% (95% confidence interval [CI]: 91-100) and 93% (95% CI: 84-100), and DPFS was 58% (95% CI: 43-77) and 39% (95% CI: 25-60), respectively. In those not on androgen deprivation therapy (ADT; n=22), the 2-yr freedom from ADT was 48%. There was no significant difference from baseline QoL observed. Limitations include small sample size, limited duration of follow-up, and lack of a control arm. CONCLUSIONS A single SABR session was feasible and associated with low morbidity in this cohort. Over one-third of patients did not progress and were free from ADT at 2-yr. QoL measures were maintained with this treatment strategy. PATIENT SUMMARY This clinical trial investigated single treatment stereotactic radiotherapy for low volume advanced prostate cancer. The approach was found to be safe with avoidance of hormone therapy in almost half of the participants at 2 yr.

Prostate-specific membrane antigen theranostics: therapy with lutetium-177

Purpose of review Prostate-specific membrane antigen (PSMA) theranostics offers a new approach for a personalized and targeted treatment for metastatic prostate cancer. Lutetium-177-labelled PSMA-ligands (177Lu-PSMA) is a radionuclide therapy that is directed to PSMA expressing prostate cancer. Clinical experience with 177Lu-PSMA in men with advanced prostate cancer is growing. The purpose of this review is to outline the mechanism of action of this therapy, summarize recent efficacy and toxicity data and highlight future direction and challenges in establishing 177Lu-PSMA treatment as part of routine clinical practice. Recent findings The first reports on safety and efficacy of 177Lu-PSMA have been retrospective series of men with advanced prostate cancer who previously failed conventional therapies and received 177Lu-PSMA on compassionate basis. These studies highlight promising efficacy, favourable toxicity profile and quality of life improvements. Limitation stem from the retroospective nature of these data with short follow-up. Summary Several studies suggest that radionuclide therapy with 177Lu-PSMA has high activity and is well tolerated. Crucial to establishing this treatment in routine clinical management will be the generation of high-level evidence from prospective trials that can confirm the encouraging patient outcomes reported to date.

Prostate-specific membrane antigen from diagnostic to therapeutic target: radionuclide therapy comes of age in prostate cancer

Without doubt, molecular imaging using PET/CT directed against prostate specific membrane antigen (PSMA) has generated much interest for its impressive accuracy in detecting prostate cancer, particularly for biochemical recurrence[1]. PSMA expression is up regulated in advanced prostate cancer, including metastatic castration resistant prostate cancer (mCRPC), and provides a novel therapeutic target for radionuclide therapy directed towards PSMA-avid disease. Radionuclide therapy relies on the identification of a suitable tumour associated ‘target’ and an appropriate ‘vehicle’ that can bind to this with high selectivity and specificity to allow delivery of a therapeutic radionuclide. This article is protected by copyright. All rights reserved.

Triple targeting of Auger emitters using octreotate conjugated to a DNA-binding ligand and a nuclear localizing signal.

Abstract Purpose: We investigated the effect of incorporation of a nuclear localization signal (NLS) into a conjugate comprising the DNA binding ligand para-iodoHoechst (PIH) and octreotate on its DNA binding and affinity to the somatostatin receptor (SSTR). Confirmation of these properties would support development of similar conjugates labelled with Auger emitters for their potential in Auger endoradiotherapy. Materials and methods: We synthesized conjugates of PIH and octreotate (PO) or PIH and NLS (PN) and a conjugate comprising PIH, NLS and octreotate (PNO). DNA-binding characteristics of PIH and conjugates were assessed using synthetic DNA oligonucleotides employing spectrophotometric titration of ligand solutions with DNA. We used membranes from the type 2 SSTR (SSTR2) overexpressing human non-small cell lung cancer cell line A427-7 to investigate the binding affinity of PNO. Results: We demonstrated PN and PNO retain specific high affinity DNA-binding properties observed for PIH, and acquire an additional non-specific binding capacity. No DNA binding was observed for PO. PNO retains its binding affinity for SSTR. Conclusions: The DNA-binding properties of PNO and its affinity for SSTR suggests that it could potentially be used for tumour-specific delivery of PIH labelled with an Auger emitter in SSTR expressing tumours.

Dosimetry of Lu-177 PSMA-617 in metastatic castration-resistant prostate cancer: correlations between pre-therapeutic imaging and “whole body” tumor dosimetry with treatment outcomes

177Lu-prostate-specific membrane antigen (PSMA)–617 enables targeted delivery of β-particle radiation to prostate cancer. We determined its radiation dosimetry and relationships to pretherapeutic imaging and outcomes. Methods: Thirty patients with prostate cancer receiving 177Lu-PSMA-617 within a prospective clinical trial (ACTRN12615000912583) were studied. Screening 68Ga-PSMA-11 PET/CT demonstrated high PSMA expression in all patients. After therapy, patients underwent quantitative SPECT/CT at 4, 24, and 96 h. Pharmacokinetic uptake and clearance at a voxel level were calculated and translated into absorbed dose using voxel S values. Volumes of interest were drawn on normal tissues and tumor to assess radiation dose, and a whole-body tumor dose was defined. Correlations between PSMA PET/CT parameters, dosimetry, and biochemical and therapeutic response were analyzed to identify relationships between absorbed dose, tumor burden, and patient physiology. Results: Mean absorbed dose to kidneys, submandibular and parotid glands, liver, spleen, and bone marrow was 0.39, 0.44, 0.58, 0.1, 0.06, and 0.11 Gy/MBq, respectively. Median whole-body tumor-absorbed dose was 11.55 Gy and correlated with prostate-specific antigen (PSA) response at 12 wk. A median dose of 14.1 Gy was observed in patients achieving a PSA decline of at least 50%, versus 9.6 Gy for those achieving a PSA decline of less than 50% (P < 0.01). Of 11 patients receiving a tumor dose of less than 10 Gy, only one achieved a PSA response of at least 50%. On screening PSMA PET, whole-body tumor SUVmean correlated with mean absorbed dose (r = 0.62), and SUVmax of the parotids correlated with absorbed dose (r = 0.67). There was an inverse correlation between tumor volume and mean dose to the parotids (r = −0.41) and kidneys (r = −0.43). The mean parotid dose was also reduced with increasing body mass (r = −0.41) and body surface area (r = −0.37). Conclusion: 177Lu-PSMA-617 delivers high absorbed doses to tumor, with a significant correlation between whole-body tumor dose and PSA response. Patients receiving less than 10 Gy were unlikely to achieve a fall in PSA of at least 50%. Significant correlations between aspects of screening 68Ga-PET/CT and tumor and normal tissue dose were observed, providing a rationale for patient-specific dosing. Reduced salivary and kidney doses were observed in patients with a higher tumor burden. The parotid dose also reduced with increasing body mass and body surface area.

Altered stress hormone response following acute exercise during prostate cancer treatment

Exercise training reduces the side effects of cancer treatments; however, the stress hormone response to acute exercise during prostate cancer (PCa) treatment is unclear. The study purpose was to examine the effects of acute exercise on circulating cortisol, epinephrine (Epi), and norepinephrine (NE) concentrations during PCa treatment with and without androgen deprivation therapy (ADT). Men with PCa (n = 11), with PCa on ADT (n = 11), and with non‐cancer controls (n = 8) had blood samples for stress hormones collected before and immediately (0 hour), 2 hours, and 24 hours after 45 minutes of intermittent cycling at 60% of peak wattage. NE increased by 385% (P < .001) at 0 hour and remained elevated at 2 hours (P < .05) with no group differences. Overall, cortisol significantly increased at 0 hour (36%, P < .012) and then significantly decreased below baseline at 2 hours (−24%, P < .001) before returning to resting levels at 24 hours. Cortisol levels during ADT were 32% lower than PCa (P = .006) with no differences vs controls. Epi increased immediately after exercise more in controls (817%, P < .001) than with ADT (700%) and PCa (333%) patients, and both cancer groups’ absolute levels were attenuated relative to controls (ADT: −54%, PCa: −52%, P = .004). Compared with age‐matched controls, PCa and ADT patients exhibited similar stress hormone responses with acute exercise for NE and cortisol but an attenuated EPI response that suggests altered adrenal function. Future studies should examine the physical stress of multiple exercise bouts to verify these findings and to explore the functional hormonal effects, such as immune and metabolic responses, during cancer treatment.

Effect of androgen deprivation therapy on the contractile properties of type I and type II skeletal muscle fibres in men with non-metastatic prostate cancer

The contractile properties of vastus lateralis muscle fibres were examined in prostate cancer (PrCa) patients undergoing androgen deprivation therapy (ADT) and in age‐ and activity‐matched healthy male subjects (Control). Mechanically‐skinned muscle fibres were exposed to a sequence of heavily Ca2+‐buffered solutions at progressively higher free [Ca2+] to determine their force‐Ca2+ relationship. Ca2+‐sensitivity was decreased in both type I and type II muscle fibres of ADT subjects relative to Controls (by −0.05 and −0.04 pCa units, respectively, P < .02), and specific force was around 13% lower in type I fibres of ADT subjects than in Controls (P = .02), whereas there was no significant difference in type II fibres. Treatment with the reducing agent dithiothreitol slightly increased specific force in type I and type II fibres of ADT subjects (by ~2%‐3%, P < .05) but not in Controls. Pure type IIx fibres were found frequently in muscle from ADT subjects but not in Controls, and the overall percentage of myosin heavy chain IIx in muscle samples was 2.5 times higher in ADT subjects (P < .01). The findings suggest that testosterone suppression can negatively impact the contractile properties by (i) reducing Ca2+‐sensitivity in both type I and type II fibres and (ii) reducing maximum specific force in type I fibres.