Actinium-225-PSMA radioligand therapy of metastatic castration-resistant prostate cancer (WARMTH Act): a multicentre, retrospective study.

BACKGROUND: Actinium-225 (225Ac) prostate-specific membrane antigen (PSMA) radioligand therapy (RLT) is a novel therapy for metastatic castration-resistant prostate cancer (mCRPC). We aimed to report the safety and antitumour activity of 225Ac-PSMA RLT of mCRPC in a large cohort of patients treated at multiple centres across the world. METHODS: This retrospective study included patients treated at seven centres in Australia, India, Germany, and South Africa. We pooled data of consecutive patients of any age and Eastern Cooperative Oncology Group performance status with histopathologically confirmed adenocarcinoma of the prostate who were treated with one or more cycles of 8 MBq 225Ac-PSMA RLT administered intravenously for mCRPC. Previous lines of mCRPC treatment included taxane-based chemotherapy, androgen-receptor-axis inhibitors, lutetium-177 (177Lu) PSMA RLT, and radium-223 dichloride. The primary outcomes were overall survival and progression-free survival. FINDINGS: Between Jan 1, 2016, and May 31, 2023, 488 men with mCRPC received 1174 cycles of 225Ac-PSMA RLT (median two cycles, IQR 2-4). The mean age of the patients was 68·1 years (SD 8·8), and the median baseline prostate-specific antigen was 169·5 ng/mL (IQR 34·6-519·8). Previous lines of treatment were docetaxel in 324 (66%) patients, cabazitaxel in 103 (21%) patients, abiraterone in 191 (39%) patients, enzalutamide in 188 (39%) patients, 177Lu-PSMA RLT in 154 (32%) patients, and radium-223 dichloride in 18 (4%) patients. The median follow-up duration was 9·0 months (IQR 5·0-17·5). The median overall survival was 15·5 months (95% CI 13·4-18·3) and median progression-free survival was 7·9 months (6·8-8·9). In 347 (71%) of 488 patients, information regarding treatment-induced xerostomia was available, and 236 (68%) of the 347 patients reported xerostomia after the first cycle of 225Ac-PSMA RLT. All patients who received more than seven cycles of 225Ac-PSMA RLT reported xerostomia. Grade 3 or higher anaemia occurred in 64 (13%) of 488 patients, leukopenia in 19 (4%), thrombocytopenia in 32 (7%), and renal toxicity in 22 (5%). No serious adverse events or treatment-related deaths were recorded. INTERPRETATION: 225Ac-PSMA RLT shows a substantial antitumour effect in mCRPC and represents a viable therapy option in patients treated with previous lines of approved agents. Xerostomia is a common side-effect. Severe bone marrow and renal toxicity are less common adverse events. FUNDING: None.

Dosimetry and pharmacokinetics of [177Lu]Lu-satoreotide tetraxetan in patients with progressive neuroendocrine tumours.

PURPOSE: To evaluate the dosimetry and pharmacokinetics of the novel radiolabelled somatostatin receptor antagonist [177Lu]Lu-satoreotide tetraxetan in patients with advanced neuroendocrine tumours (NETs). METHODS: This study was part of a phase I/II trial of [177Lu]Lu-satoreotide tetraxetan, administered at a median cumulative activity of 13.0 GBq over three planned cycles (median activity/cycle: 4.5 GBq), in 40 patients with progressive NETs. Organ absorbed doses were monitored at each cycle using patient-specific dosimetry; the cumulative absorbed-dose limits were set at 23.0 Gy for the kidneys and 1.5 Gy for bone marrow. Absorbed dose coefficients (ADCs) were calculated using both patient-specific and model-based dosimetry for some patients. RESULTS: In all evaluated organs, maximum [177Lu]Lu-satoreotide tetraxetan uptake was observed at the first imaging timepoint (4 h after injection), followed by an exponential decrease. Kidneys were the main route of elimination, with a cumulative excretion of 57-66% within 48 h following the first treatment cycle. At the first treatment cycle, [177Lu]Lu-satoreotide tetraxetan showed a median terminal blood half-life of 127 h and median ADCs of [177Lu]Lu-satoreotide tetraxetan were 5.0 Gy/GBq in tumours, 0.1 Gy/GBq in the bone marrow, 0.9 Gy/GBq in kidneys, 0.2 Gy/GBq in the liver and 0.8 Gy/GBq in the spleen. Using image-based dosimetry, the bone marrow and kidneys received median cumulative absorbed doses of 1.1 and 10.8 Gy, respectively, after three cycles. CONCLUSION: [177Lu]Lu-satoreotide tetraxetan showed a favourable dosimetry profile, with high and prolonged tumour uptake, supporting its acceptable safety profile and promising efficacy. TRIAL REGISTRATION: NCT02592707. Registered October 30, 2015.

A phase I/II study of the safety and efficacy of [177Lu]Lu-satoreotide tetraxetan in advanced somatostatin receptor-positive neuroendocrine tumours.

PURPOSE: We present the results of an open-label, phase I/II study evaluating the safety and efficacy of the novel somatostatin receptor (SSTR) antagonist [177Lu]Lu-satoreotide tetraxetan in 40 patients with previously treated, progressive neuroendocrine tumours (NETs), in which dosimetry was used to guide maximum administered activity. METHODS: This study was conducted in two parts. Part A consisted of 15 patients who completed three cycles of [177Lu]Lu-satoreotide tetraxetan at a fixed administered activity and peptide amount per cycle (4.5 GBq/300 µg). Part B, which included 25 patients who received one to five cycles of [177Lu]Lu-satoreotide tetraxetan, evaluated different administered activities (4.5 or 6.0 GBq/cycle) and peptide amounts (300, 700, or 1300 µg/cycle), limited to a cumulative absorbed radiation dose of 23 Gy to the kidneys and 1.5 Gy to the bone marrow. RESULTS: Median cumulative administered activity of [177Lu]Lu-satoreotide tetraxetan was 13.0 GBq over three cycles (13.1 GBq in part A and 12.9 GBq in part B). Overall, 17 (42.5%) patients experienced grade ≥ 3 treatment­related adverse events; the most common were lymphopenia, thrombocytopenia, and neutropenia. No grade 3/4 nephrotoxicity was observed. Two patients developed myeloid neoplasms considered treatment related by the investigator. Disease control rate for part A and part B was 94.7% (95% confidence interval [CI]: 82.3-99.4), and overall response rate was 21.1% (95% CI: 9.6-37.3). CONCLUSION: [177Lu]Lu-satoreotide tetraxetan, administered at a median cumulative activity of 13.0 GBq over three cycles, has an acceptable safety profile with a promising clinical response in patients with progressive, SSTR-positive NETs. A 5-year long-term follow-up study is ongoing. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02592707. Registered October 30, 2015.

Potential utility of B-type natriuretic peptides in secondary prevention following percutaneous coronary intervention in remote communities of Western Australia.

INTRODUCTION: A third of all acute coronary events that present in the Australian population occur in patients with established coronary heart disease. This study assessed the prognostic value of combined B-type natriuretic peptides (BNP) measurement and quantitative myocardial perfusion scan (MPS) data for cardiac events (CE). MATERIAL AND METHODS: This retrospective cohort study involved 133 patients from rural Western Australia. The cut-off for normality was 6.0 for qualitative summed difference scores (SDS) of MPS and 400 pg/mL for BNP. RESULTS: Patients with no CE had a mean SDS and BNP (1.52 with a 95% CI of 0.34 to 2.69), (175.9 with a 95% CI of 112.7-239.1) that was lower than patients with CE (6.54 with 95% CI 4.18-9.89) (P = 0.0003), (669.1 with 95% CI 543.9-794.3) (P < 0.0001). The sensitivity and specificity of combined testing for predicting CE respectively were 79.6% and 86.3% for SDS, 84.6% and 94.1% for BNP, and 100% and 92.7% for SDS and BNP combined. DISCUSSION AND CONCLUSION: Elevated BNP is marginally superior to MPS in predicting CEs in patients who have previously undergone percutaneous coronary intervention (PCI); however, MPS can identify the region of myocardium most at risk. Routine BNP monitoring in this subgroup may serve as secondary prevention by identifying subclinical disease.

Rural communities are disproportionately affected by preventable coronary heart disease-related deaths and access to cardiac imaging techniques can be infrequent or unavailable.Secondary prevention strategies can reduce hospital readmissions and contribute to improving the management of chronic conditions.This study demonstrated that elevated B-type natriuretic peptides levels were marginally superior to myocardial perfusion scans in predicting cardiac events in patients with prior percutaneous coronary intervention.Monitoring BNP levels in rural patients with prior percutaneous coronary interventions is a relatively non-invasive and inexpensive, and may lead to improved risk estimation, identify the subclinical disease and provoke further investigation as clinically appropriate.

Lutetium-177 Labelled Anti-PSMA Monoclonal Antibody (Lu-TLX591) Therapy for Metastatic Prostate Cancer: Treatment Toxicity and Outcomes.

INTRODUCTION: Whilst prostate cancer is the fourth most common cancer globally, effective therapies for patients with advanced disease are lacking. In recent years, interest in using theranostic agents to treat castrate-resistant prostate cancer (CRPC) and metastatic prostate cancer has emerged. Lu-TLX591 monoclonal antibody is a potential agent of significance; however, to date, reports on its toxicity and efficacy have been limited to small clinical trials in heavily pretreated patients. This retrospective study describes the real-world toxicity and efficacy profile of Lu-TLX591. METHODS: Eighteen patients received Lu-TLX591 at two private oncology centres in Australia. Patients were eligible if they had CRPC or metastatic prostate cancer and prostate-specific membrane antigen (PSMA)-avid disease confirmed by PSMA-positron emission tomography (PET). Patients received two cycles of Lu-TLX591 monoclonal antibody (177 Lu-DOTA-rosopatamab) each dosed from 1.01-2.85 GBq, 14 days apart. Patient side effects, blood test results and radiology reports were recorded on the patient's electronic medical record (eMR). RESULTS: Prominent side effects included fatigue (55.6%), anorexia (16.7%), nausea (11.1%), and transfusion reactions (11.1%). All-grade haematological toxicities included lymphopenia (61.1%), anaemia (22.2%), leukopenia (27.8%), neutropenia (27.8%), and thrombocytopenia (27.8%). Grade 4 toxicity included lymphopenia (6.7%) and thrombocytopenia (6.7%). Patients' prostate-specific antigen (PSA) responses were as follows; ≥ 30% PSA decline (27.8%), ≥ 50% PSA decline (11.4%) and any PSA decline (38.9%). Follow-up radiology revealed 54.5% stable disease, 45.4% disease progression and 9.1% disease regression. CONCLUSION: Lu-TLX591 was safely administered at acceptable toxicity and its efficacy reflects previous clinical trials. Larger studies are required and are underway (NCT04786847; NCT05146973; NCT04876651) to determine Lu-TLX591 effectiveness amongst different prostate cancer populations and compare its efficacy against peptide-based radiopharmaceutical agents.

Efficacy and Haematologic Toxicity of Palliative Radioligand Therapy of Metastatic Castrate-Resistant Prostate Cancer with Lutetium-177-Labeled Prostate-Specific Membrane Antigen in Heavily Pre-Treated Patients.

BACKGROUND: Metastatic castration-resistant prostate cancer (mCRPC) remains a significant contributor to the global cancer burden. lutetium-177-prostate-specific membrane antigen radioligand therapy (177Lu-PSMA RLT) is an effective salvage treatment. However, studies have highlighted haematologic toxicity as an adverse event of concern. We report our single-centre experience of compassionate access palliative 177Lu-DOTAGA-(I-y)fk(Sub-KuE) (177Lu-PSMA I&T) with respect to efficacy and haematologic safety. METHODS: Patients with mCRPC and adequate bone marrow/liver function were included. All patients included underwent baseline and response assessment by Gallium-68-PSMA-11 positron emission tomography/computed tomography (68Ga-PSMA-11 PET/CT). Prescribed activity of therapy was a median 6.24 GBq per patient per cycle (IQR1.29 GBq), administered in 8-week intervals, up to four cycles. Response was assessed by prostate specific antigen (PSA) and a week-12 PET/CT. Incidence of grade ≥ 3 haematologic toxicity, including association with risk factors (age ≥ 70 years, prior/concurrent therapy, presence of metastases, and number of cycles completed), was analysed. RESULTS: One hundred patients completed one cycle of 177Lu PSMA I&T and underwent response assessment by both PSA and PET/CT. Two patients had an uninterpretable week-12 PET/CT. Median age was 70 (50-89), median number of prior therapies was three (1-6), and median follow up was 12-months. Fifty-four percent achieved a PSA response. Disease control rate (DCR) by PET/CT was 64% (29% SD, 34% PR, and 1% CR). Disease control by PET/CT was associated with an improved one-year overall survival (OS) compared to non-responders, median OS not-reached vs 10-months (p < 0.0001; 95% CI: 0.08-0.44). Regarding haematologic toxicity, 11% experienced a grade ≥ 3 cytopenia (self-limiting). No cases of myelodysplasia/acute leukaemia (MDS/AL) have been recorded. No association with risk factors was demonstrated. CONCLUSION: 177Lu-PSMA I&T is a safe and effective palliative outpatient treatment for mCRPC. 68Ga-PSMA-11 PET/CT response is associated with an improved one-year OS and may be used to adapt therapy.

Gallium-68 prostate-specific membrane antigen positron emission tomography/computed tomography compared with diagnostic computed tomography in relapsed prostate cancer.

The aim of this study was to evaluate if prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) has a higher detection rate compared to standard contrast CT imaging for patients with a rising prostate-specific antigen (PSA) following definitive treatment (i.e., curative radical prostatectomy, radiotherapy, and brachytherapy) for prostate cancer in a private hospital setting. A retrospective single-site clinical audit was conducted on 150 PSMA PET/CT scans done for patients with a rising PSA after definitive treatment for prostate cancer. All studies were performed using I and T Ga-68 PSMA produced on a Scintomics radiopharmaceutical unit (Munich). All scans were performed on a GE 710 PET/CT scanner. All studies were compared to standard CT and other imaging. Of the 150 patients who had a 68Gallium (Ga)-PSMA PET/CT for a rise in their PSA levels, 102/150 (68%) of patients had PSMA-avid scans compared to the conventional imaging group which had an overall detection rate of 42% (63/150). The rates of detection were 100%, 90%, 92%, 67%, and 25% at PSA levels of >10 µg/L, 5-10 µg/L, >1.5 µg/L, 0.5-1.5 µg/L, and <0.5 µg/L, respectively. PSMA PET/CT also solely picked up 39/102 (38%) of prostate cancer relapses compared to the conventional imaging group. In our study of 150 patients with biochemical recurrence of prostate cancer, 68Ga-PSMA PET/CT demonstrated a superior detection rate (P < 0.05) compared to conventional imaging, including patients with low PSA levels (<0.5 µg/L).

Fluoro-2-deoxy-D-glucose (FDG)-PET in APOEepsilon4 carriers in the Australian population.

Apolipoprotein E-epsilon4 (APOEepsilon4) has been associated with increased risk of developing Alzheimer's disease (AD) and regional cerebral glucose hypometabolism, as measured by fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET). We report here preliminary data from studies that aim to determine whether cerebral glucose hypometabolism is observed in APOEepsilon4 positive, cognitively intact individuals between the ages of 50 and 80, and whether there is an additional impact of subjective memory complainer (SMC) status on glucose metabolism determined by NeuroStat analysis. FDG-PET was conducted in 30 community dwelling, APOE-epsilon4 carriers without clinical evidence of dementia and objective cognitive impairment as assessed using a neuropsychological battery. Neurological soft-signs (NSS) were also assessed. Glucose hypometabolism was demonstrated in the anterior and posterior cingulate cortex and in the temporal association cortices in APOEepsilon4 carriers compared to the normative NeuroStat database. This pattern was particularly evident in APOEepsilon4 heterozygous individuals. SMC showed hypometabolism in the aforementioned brain regions, whereas non-SMC showed no significant pattern of glucose hypometabolism. FDG-PET with NeuroStat analysis showed that APOEepsilon4 carriers have mild glucose hypometabolism in areas associated with AD. SMC may be associated with AD-related differences in regional cerebral glucose metabolism. These findings are currently being investigated in a larger group of APOEepsilon4 carriers.

Review of Gallium-68 PSMA PET/CT Imaging in the Management of Prostate Cancer.

Over 90% of prostate cancers over-express prostate specific membrane antigen (PSMA) and these tumor cells may be accurately targeted for diagnosis by 68Ga-PSMA-positron emission tomography/computed tomography (68Ga-PSMA-PET/CT) imaging. This novel molecular imaging modality appears clinically to have superseded CT, and appears superior to MR imaging, for the detection of metastatic disease. 68Ga-PSMA PET/CT has the ability to reliably stage prostate cancer at presentation and can help inform an optimal treatment approach. Novel diagnostic applications of 68Ga-PSMA PET/CT include guiding biopsy to improve sampling accuracy, and guiding surgery and radiotherapy. In addition to facilitating the management of metastatic castrate resistant prostate cancer (mCRPC), 68Ga-PSMA can select patients who may benefit from targeted systemic radionuclide therapy. 68Ga-PSMA is the diagnostic positron-emitting theranostic pair with the beta emitter Lutetium-177 PSMA (177Lu-PSMA) and alpha-emitter Actinium-225 PSMA (225Ac-PSMA) which can both be used to treat PSMA-avid metastases of prostate cancer in the molecular tumor-targeted approach of theranostic nuclear oncology.

Salvage Radiopeptide Therapy of Advanced Castrate-Resistant Prostate Cancer with Lutetium-177-Labeled Prostate-Specific Membrane Antigen: Efficacy and Safety in Routine Practice.

BACKGROUND: Prostate-specific membrane antigen (PSMA)-based radiopeptide/radioligand therapy represents a rapidly expanding field in the management of metastatic castrate-resistant prostate cancer (mCRPC). However, there remains concern for the development of significant toxicities in heavily pretreated patients. In this study, the authors present their local experience, with respect to efficacy and toxicity, of 22 consecutive patients treated with lutetium-177-DOTAGA-(I-y)fk(Sub-KuE) or 177Lu-PSMA I&T radioimmunotherapy for progressive mCRPC, followed up over 1 year. MATERIALS AND METHODS: All patients had progressive mCRPC, an European Cooperative Oncology Group (ECOG) ≤2 with adequate bone marrow and liver function. 177Lu-PSMA I&T therapy was administered at 8-week intervals with a mean prescribed activity of 5.5 GBq (gigabecquerel) per patient. RESULTS: Twenty patients had evaluable results, median age of 71 years, and median duration of follow-up of 17 months. Three patients (15%) experienced a G1/2 myelotoxicity and four (20%) G3/4. No incidences of myelodysplasia/acute leukemia have been identified. All toxicities were self-limiting. Baseline cytopenia was predictive of the development of subsequent G3/4 myelotoxicity (p = 0.0035). Eight patients (40%) experienced an objective PSA response, with a median time to response of 15 weeks. The median time to PSA progression was not reached. Patients receiving three cycles of therapy were statistically more likely to experience a disease response when compared to those treated with one, two, or four cycles (p < 0.0001). CONCLUSIONS: 177Lu-PSMA I&T radioimmunotherapy of progressive mCRPC is safe and effective with three cycles being the potential optimal number for determining long-term disease response.

The role of 68Ga-PSMA-I&T PET/CT in the pretreatment staging of primary prostate cancer.

OBJECTIVES: This retrospective study aimed to evaluate the role of Ga-PSMA-I&T PET/CT in the primary staging of newly diagnosed prostate cancer (PCa), with a focus on the detection of metastatic nodal disease. Correlation of the rate of detection of metastatic disease by Ga-PSMA-I&T PET/CT with the Gleason score (GS) and serum prostate-specific antigen (PSA) was performed to determine the GS and PSA criteria defining patients who would benefit from Ga-PSMA-I&T PET/CT imaging for staging, risk stratification and therapy optimization. PATIENTS AND METHODS: Patient data and images from 70 patients with a recent diagnosis of prostate cancer who had undergone Ga-PSMA-I&T PET/CT were analysed retrospectively. Data and images were analysed for the rate of detection of primary and metastatic PCa, and correlation with PSA and GS. RESULTS: The rate of detection of primary tumour by Ga-PSMA-I&T for patients with serum PSA less than 5 ng/ml was 73%. The corresponding rate was 90% for patients with PSA 5-10 ng/ml and 97% for patients with PSA more than 10 ng/ml. Metastatic PCa and/or infiltrative disease was detected in 24/70 study patients in total: 1/11 patients with PSA less than 5 ng/ml and 23/59 patients with serum PSA at least 5 ng/ml. The rate of detection of metastatic PCa was greater in patients with GS 9 or more (48%) relative to those with GS 8 (32%) or GS ≤7 (18%). CONCLUSION: A role for Ga-PSMA-I&T PET/CT in primary PCa staging of high-grade disease (GS 8 or more and PSA >10 ng/ml) has been shown. There was a low rate of detection of PSMA-avid metastases in low-grade disease (GS 7 or less and PSA <5 ng/ml), suggesting that there is a limited role for this modality in such cases.

Epidemiology of ductal carcinoma in situ in Western Australia: implications for surgical margins and management.

BACKGROUND: In 2010, the Australian Institute of Health and Welfare published a report examining the characteristics of Australian women diagnosed with ductal carcinoma in situ (DCIS). This study identified the characteristics of women who were diagnosed with DCIS in Western Australia (WA) 1996-2005, and built on a national study by determining the rate of second operation and breast cancer events (BCE) in WA. METHODS: A retrospective analysis of data from the WA Cancer Registry and the Hospital Morbidity Database was undertaken. The main outcome measures were histological characteristics, second operation rate, breast cancer events. RESULTS: A total of 1356 cases of DCIS were diagnosed in WA between 1996 and 2005, with a minimum 5-year follow-up. The age-standardised incidence rate in 2005 was 15.4 per 100,000 women. 72 % of patients received breast-conserving therapy for primary treatment, 18 % of patients requiring a second operation to obtain adequate margins and 35 % of patients received postoperative radiotherapy. 17.3 % of cases had a subsequent BCE, with the 5- and 10-year probabilities being 4.36 and 8.27 %, respectively. A BCE was significantly associated with age (p < 0.001), no second operation (p < 0.001) and no radiotherapy (p = 0.049 recurrence, p = 0.043 invasion). CONCLUSION: This study supports the need to ensure adequate margins during primary surgery for DCIS is obtained to reduce the need for a second operation or the risk of a subsequent BCE. The consideration of mastectomy versus radiotherapy should be made in conjunction with the identified risk factors, specifically age and whether a second operation was performed.

Ectopic parathyroid adenoma localised with sestamibi SPECT and image-fused computed tomography.

Confident localisation of ectopic parathyroid adenomas, particularly those outside the neck, can be difficult. Even preoperative radiological imaging may not be helpful, as there are few characteristic findings. We report a case in which hyperfunctioning ectopic parathyroid tissue in the mediastinum was detected with technetium-99m-sestamibi single-photon emission computed tomography and accurately localised non-invasively with image-fused computed tomography. This technique directly modified management.