Medicine (St Vincent's) - Research Publications

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    Utility of 68Ga-DOTA-Exendin-4 positron emission tomography-computed tomography imaging in distinguishing between insulinoma and nesidioblastosis in patients with confirmed endogenous hyperinsulinaemic hypoglycaemia
    Kalff, V ; Iravani, A ; Akhurst, T ; Pattison, DA ; Eu, P ; Hofman, MS ; Hicks, RJ (WILEY, 2021-10)
    BACKGROUND: Because management is very different, it is important to differentiate between small focal insulinomas and diffuse pancreatic dysplasia (nesidioblastosis) in patients with confirmed endogenous hyperinsulinaemic hypoglycaemia (EHH). Most insulinomas highly express glucagon-like peptide-1 receptors enabling positron emission tomography-computed tomography imaging with its radiolabelled analogue; 68 Ga-DOTA-Exendin-4 (Exendin). AIM: To determine: (i) the utility of Exendin in EHH patients in a clinical setting; and (ii) whether the degree of Exendin uptake differentiates non-insulinoma pancreatogenous hypoglycaemia syndrome (NIPHS) from post-gastric bypass hypoglycaemia (PGBH). METHODS: This retrospective study reviewed the clinical, biochemistry and prior imaging findings in confirmed EHH patients referred for Exendin. Accuracy of Exendin was based on surgical findings and treatment outcomes. Finally, average Exendin uptake (SUVmax) of five PGBH studies was compared with the SUVmax of a key NIPHS case report. RESULTS: Twenty of 25 consecutive patients had confirmed EHH. Exendin located insulinomas in eight of nine patients enabling successful surgical excision with rapid and durable cure. Exendin correctly identified diffuse nesidioblastosis in two of three cases requiring partial pancreatectomy for hypoglycaemia control. All three relapsed within 1.7 years with one needing completion pancreatectomy. Establishing the cause in the remainder relied on other investigations, clinical correlation and response to empirical treatment. Finally, Exendin SUVmax could not distinguish between NIPHS and PGBH. CONCLUSION: In EHH patients, Exendin accurately identifies the site of insulinoma and thereby differentiates it from nesidioblastosis but negative findings should not be ignored. Exendin is unlikely to differentiate between normal pancreatic uptake, NIPHS and PGBH.
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    ImmunoPET: IMaging of cancer imMUNOtherapy targets with positron Emission Tomography: a phase 0/1 study characterising PD-L1 with 89Zr-durvalumab (MEDI4736) PET/CT in stage III NSCLC patients receiving chemoradiation study protocol.
    Hegi-Johnson, F ; Rudd, SE ; Wichmann, C ; Akhurst, T ; Roselt, P ; Trinh, J ; John, T ; Devereux, L ; Donnelly, PS ; Hicks, R ; Scott, AM ; Steinfort, D ; Fox, S ; Blyth, B ; Parakh, S ; Hanna, GG ; Callahan, J ; Burbury, K ; MacManus, M (BMJ Publishing Group, 2022-11-18)
    BACKGROUND: ImmunoPET is a multicentre, single arm, phase 0-1 study that aims to establish if 89Zr-durvalumab PET/CT can be used to interrogate the expression of PD-L1 in larger, multicentre clinical trials. METHODS: The phase 0 study recruited 5 PD-L1+ patients with metastatic non-small cell lung cancer (NSCLC). Patients received 60MBq/70 kg 89Zr-durva up to a maximum of 74 MBq, with scan acquisition at days 0, 1, 3 or 5±1 day. Data on (1) Percentage of injected 89Zr-durva dose found in organs of interest (2) Absorbed organ doses (µSv/MBq of administered 89Zr-durva) and (3) whole-body dose expressed as mSv/100MBq of administered dose was collected to characterise biodistribution.The phase 1 study will recruit 20 patients undergoing concurrent chemoradiotherapy for stage III NSCLC. Patients will have 89Zr-durva and FDG-PET/CT before, during and after chemoradiation. In order to establish the feasibility of 89Zr-durva PET/CT for larger multicentre trials, we will collect both imaging and toxicity data. Feasibility will be deemed to have been met if more than 80% of patients are able complete all trial requirements with no significant toxicity. ETHICS AND DISSEMINATION: This phase 0 study has ethics approval (HREC/65450/PMCC 20/100) and is registered on the Australian Clinical Trials Network (ACTRN12621000171819). The protocol, technical and clinical data will be disseminated by conference presentations and publications. Any modifications to the protocol will be formally documented by administrative letters and must be submitted to the approving HREC for review and approval. TRIAL REGISTRATION NUMBER: Australian Clinical Trials Network ACTRN12621000171819.
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    Single-nuclei and bulk-tissue gene-expression analysis of pheochromocytoma and paraganglioma links disease subtypes with tumor microenvironment
    Zethoven, M ; Martelotto, L ; Pattison, A ; Bowen, B ; Balachander, S ; Flynn, A ; Rossello, FJ ; Hogg, A ; Miller, JA ; Frysak, Z ; Grimmond, S ; Fishbein, L ; Tischler, AS ; Gill, AJ ; Hicks, RJ ; Dahia, PLM ; Clifton-Bligh, R ; Pacak, K ; Tothill, RW (NATURE PORTFOLIO, 2022-10-21)
    Pheochromocytomas (PC) and paragangliomas (PG) are rare neuroendocrine tumors associated with autonomic nerves. Here we use single-nuclei RNA-seq and bulk-tissue gene-expression data to characterize the cellular composition of PCPG and normal adrenal tissues, refine tumor gene-expression subtypes and make clinical and genotypic associations. We confirm seven PCPG gene-expression subtypes with significant genotype and clinical associations. Tumors with mutations in VHL, SDH-encoding genes (SDHx) or MAML3-fusions are characterized by hypoxia-inducible factor signaling and neoangiogenesis. PCPG have few infiltrating lymphocytes but abundant macrophages. While neoplastic cells transcriptionally resemble mature chromaffin cells, early chromaffin and neuroblast markers are also features of some PCPG subtypes. The gene-expression profile of metastatic SDHx-related PCPG indicates these tumors have elevated cellular proliferation and a lower number of non-neoplastic Schwann-cell-like cells, while GPR139 is a potential theranostic target. Our findings therefore clarify the diverse transcriptional programs and cellular composition of PCPG and identify biomarkers of potential clinical significance.
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    Perspectives on joint EANM/SNMMI/ANZSNM practice guidelines/procedure standards for [18F]FDG PET/CT imaging during immunomodulatory treatments in patients with solid tumors
    Lopci, E ; Aide, N ; Dimitrakopoulou-Strauss, A ; Dercle, L ; Iravani, A ; Seban, RD ; Sachpekidis, C ; Humbert, O ; Gheysens, O ; Glaudemans, AWJM ; Weber, WA ; Van den Abbeele, AD ; Wahl, RL ; Scott, AM ; Pandit-Taskar, N ; Hicks, RJ (BMC, 2022-12-20)
    Response assessment in the context of immunomodulatory treatments represents a major challenge for the medical imaging community and requires a multidisciplinary approach with involvement of oncologists, radiologists, and nuclear medicine specialists. There is evolving evidence that [18F]FDG PET/CT is a useful diagnostic modality for this purpose. The clinical indications for, and the principal aspects of its standardization in this context have been detailed in the recently published "Joint EANM/SNMMI/ANZSNM practice guidelines/procedure standards on recommended use of [18F]FDG PET/CT imaging during immunomodulatory treatments in patients with solid tumors version 1.0". These recommendations arose from a fruitful collaboration between international nuclear medicine societies and experts in cancer treatment. In this perspective, the key elements of the initiative are reported, summarizing the core aspects of the guidelines for radiologists and nuclear medicine physicians. Beyond the previous guidelines, this perspective adds further commentary on how this technology can advance development of novel therapeutic approaches and guide management of individual patients.
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    Alpelisib Monotherapy for PI3K-Altered Pretreated Advanced Breast Cancer A Phase II Study
    Savas, P ; Lo, LL ; Luen, SJ ; Blackley, EF ; Callahan, J ; Moodie, K ; van Geelen, CT ; Ko, Y-A ; Weng, C-F ; Wein, L ; Silva, MJ ; Bujak, AZ ; Yeung, MM ; Ftouni, S ; Hicks, RJ ; Francis, PA ; Lee, CK ; Dawson, S-J ; Loi, S (AMER ASSOC CANCER RESEARCH, 2022-09)
    UNLABELLED: There is limited knowledge on the benefit of the α-subunit-specific PI3K inhibitor alpelisib in later lines of therapy for advanced estrogen receptor-positive (ER+) HER2- and triple-negative breast cancer (TNBC). We conducted a phase II multicohort study of alpelisib monotherapy in patients with advanced PI3K pathway mutant ER+HER2- and TNBC. In the intention-to-treat ER+ cohort, the overall response rate was 30% and the clinical benefit rate was 36%. A decline in PI3K pathway mutant circulating tumor DNA (ctDNA) levels from baseline to week 8 while on therapy was significantly associated with a partial response, clinical benefit, and improved progression-free-survival [HR 0.24; 95% confidence interval (CI), 0.083-0.67, P = 0.0065]. Detection of ESR1 mutations at baseline in plasma was also associated with clinical benefit and improved progression-free survival (HR 0.22; 95% CI, 0.078-0.60, P = 0.003). SIGNIFICANCE: Alpelisib monotherapy displayed efficacy in heavily pretreated ER+ breast cancer with PIK3CA mutations. PIK3CA mutation dynamics in plasma during treatment and ESR1 mutations detected in plasma at baseline were candidate biomarkers predictive of benefit from alpelisib, highlighting the utility of ctDNA assays in this setting. This article is highlighted in the In This Issue feature, p. 2007.
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    [18F]FDG-PET-CT compared with CT for persistent or recurrent neutropenic fever in high-risk patients (PIPPIN): a multicentre, open-label, phase 3, randomised, controlled trial
    Douglas, A ; Thursky, K ; Spelman, T ; Szer, J ; Bajel, A ; Harrison, S ; Tio, SY ; Bupha-Intr, O ; Tew, M ; Worth, L ; Teh, B ; Chee, L ; Ng, A ; Carney, D ; Khot, A ; Haeusler, G ; Yong, M ; Trubiano, J ; Chen, S ; Hicks, R ; Ritchie, D ; Slavin, M (ELSEVIER SCI LTD, 2022-08)
    BACKGROUND: Management of neutropenic fever in high-risk haematology patients is challenging; there are often few localising clinical features, and diagnostic tests have poor sensitivity and specificity. We aimed to compare how [18F]flurodeoxyglucose ([18F]FDG)-PET-CT scans and conventional CT scans affected the guidance of antimicrobial management and the outcomes of patients with persistent or recurrent neutropenic fever. METHODS: We did a multicentre, open-label, phase 3, randomised, controlled trial in two tertiary referral hospitals in Australia. We recruited adults aged 18 years or older who were receiving conditioning chemotherapy for haematopoietic stem-cell transplantation or chemotherapy for acute leukaemia and had persistent (>72 h) or recurrent (new fever beyond 72 h of initial onset interspersed with >48 h defervescence) neutropenic fever. Exclusion criteria were pregnancy, allergy to iodinated contrast, or estimated glomerular filtration rate of less than 30 mL/min. Patients were randomly assigned by computer-generated randomisation chart (1:1) to [18F]FDG-PET-CT or conventional CT. Masking was not possible because of the nature of the investigation. Scans were done within 3 days of random assignment. The primary endpoint was a composite of starting, stopping, or changing the spectrum (broadening or narrowing) of antimicrobial therapy-referred to here as antimicrobial rationalisation-within 96 h of the assigned scan, analysed per protocol. This trial is registered with clinicaltrials.gov, NCT03429387, and is complete. FINDINGS: Between Jan 8, 2018, and July 23, 2020, we assessed 316 patients for eligibility. 169 patients were excluded and 147 patients were randomly assigned to either [18F]FDG-PET-CT (n=73) or CT (n=74). Nine patients did not receive a scan per protocol, and two participants in each group were excluded for repeat entry into the study. 65 patients received [18F]FDG-PET-CT (38 [58%] male; 53 [82%] White) and 69 patients received CT (50 [72%] male; 58 [84%] White) per protocol. Median follow up was 6 months (IQR 6-6). Antimicrobial rationalisation occurred in 53 (82%) of 65 patients in the [18F]FDG-PET-CT group and 45 (65%) of 69 patients in the CT group (OR 2·36, 95% CI 1·06-5·24; p=0·033). The most frequent component of antimicrobial rationalisation was narrowing spectrum of therapy, in 28 (43%) of 65 patients in the [18F]FDG-PET-CT group compared with 17 (25%) of 69 patients in the CT group (OR 2·31, 95% CI 1·11-4·83; p=0·024). INTERPRETATION: [18F]FDG-PET-CT was associated with more frequent antimicrobial rationalisation than conventional CT. [18F]FDG-PET-CT can support decision making regarding antimicrobial cessation or de-escalation and should be considered in the management of patients with haematological diseases and persistent or recurrent high-risk neutropenic fever after chemotherapy or transplant conditioning. FUNDING: National Health and Medical Research Council Centre of Research Excellence (APP1116876), Melbourne Health foundation, Gilead Research Fellowship grants supported this study.
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    Imaging immunity in patients with cancer using positron emission tomography
    Hegi-Johnson, F ; Rudd, S ; Hicks, RJ ; De Ruysscher, D ; Trapani, JA ; John, T ; Donnelly, P ; Blyth, B ; Hanna, G ; Everitt, S ; Roselt, P ; MacManus, MP (NATURE PORTFOLIO, 2022-04-07)
    Immune checkpoint inhibitors and related molecules can achieve tumour regression, and even prolonged survival, for a subset of cancer patients with an otherwise dire prognosis. However, it remains unclear why some patients respond to immunotherapy and others do not. PET imaging has the potential to characterise the spatial and temporal heterogeneity of both immunotherapy target molecules and the tumor immune microenvironment, suggesting a tantalising vision of personally-adapted immunomodulatory treatment regimens. Personalised combinations of immunotherapy with local therapies and other systemic therapies, would be informed by immune imaging and subsequently modified in accordance with therapeutically induced immune environmental changes. An ideal PET imaging biomarker would facilitate the choice of initial therapy and would permit sequential imaging in time-frames that could provide actionable information to guide subsequent therapy. Such imaging should provide either prognostic or predictive measures of responsiveness relevant to key immunotherapy types but, most importantly, guide key decisions on initiation, continuation, change or cessation of treatment to reduce the cost and morbidity of treatment while enhancing survival outcomes. We survey the current literature, focusing on clinically relevant immune checkpoint immunotherapies, for which novel PET tracers are being developed, and discuss what steps are needed to make this vision a reality.
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    FDG-PET/CT imaging for evaluating durable responses to immune check point inhibitors in patients with advanced cutaneous squamous cell carcinoma
    McLean, LS ; Cavanagh, K ; Hicks, RJ ; Callahan, J ; Xie, J ; Cardin, A ; Lim, AM ; Rischin, D (BMC, 2021-10-13)
    BACKGROUND: The role of FDG-PET/CT imaging in assessing response to immunotherapy in advanced cutaneous squamous cell carcinoma (CSCC) is unknown. This study compared complete metabolic response (CMR) rates by FDG-PET and RECIST1.1 via CT or MRI in patients on cemiplimab for > 10 months. METHODS: This was a single-centre retrospective study of 15 patients treated with cemiplimab for advanced CSCC who had CT/MRI and FDG-PET/CT at > 10 months to assess metabolic treatment response. The median age was 73 years (range 55-84) and 93% were male. RECIST1.1 and PERCIST1.0 tumor responses were evaluated by blinded readers. RESULTS: Seventy-three percent (11/15) (95%CI 44.9, 92.2%) achieved a CMR on PET. Of these 11, on RECIST1.1 there was one complete response, 9 partial responses and one stable disease. CONCLUSIONS: In patients on cemiplimab for > 10 months, there was discordance between CR rates on FDG-PET versus RECIST1.1. FDG-PET/CT may have utility for clarifying depth of response in patients treated with immunotherapy for CSCC.
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    Intratumoral T-cell receptor repertoire is predictive of interim PET scan results in patients with diffuse large B-cell lymphoma treated with rituximab/cyclophosphamide/doxorubicin/prednisolone/vincristine (R-CHOP) chemoimmunotherapy
    Shanavas, M ; Law, S-C ; Hertzberg, M ; Hicks, RJ ; Seymour, JF ; Li, Z ; Merida de Long, L ; Nath, K ; Sabdia, MB ; Gunawardana, J ; Gandhi, MK ; Keane, C (WILEY, 2021)
    OBJECTIVES: A diverse intratumoral T-cell receptor (TCR) repertoire is associated with improved survival in diffuse large B-cell lymphoma (DLBCL) treated with rituximab/cyclophosphamide/doxorubicin/prednisolone/vincristine (R-CHOP) chemoimmunotherapy. We explored the impact of intratumoral TCR repertoire on interim PET (iPET) done after four cycles of R-CHOP, the relationships between intratumoral and circulating repertoire, and the phenotypes of expanded clonotypes. METHODS: We sequenced the third complementarity-determining region of TCRβ in tumor samples, blood at pre-therapy and after four cycles of R-CHOP in 35 patients enrolled in ALLGNHL21 trial in high-risk DLBCL. We correlated the TCR diversity metrics with iPET status, gene expression profiles and HLA-class I genotypes. We then sequenced the FACS-sorted peripheral blood T cells in six patients, and pentamer-sorted EBV-specific CD8+ T cells in one patient from this cohort. RESULTS: Compared with iPET- patients, the intratumoral TCR repertoire in iPET+ patients was characterised by higher cumulative frequency of abundant clonotypes and higher productive clonality. There was a variable overlap between circulating and intratumoral repertoires, with the dominant intratumoral clonotypes more likely to be detected in the blood. The majority of shared clonotypes were CD8+ PD-1HI T cells, and CD8+ T cells had the largest clonal expansions in tumor and blood. In a patient with EBV+ DLBCL, EBV-specific intratumoral clonotypes were trackable in the blood. CONCLUSION: This study demonstrates that clonally expanded intratumoral TCR repertoires are associated with iPET+ and that the blood can be used to track tumor-associated antigen-specific clonotypes. These findings assist the rationale design and therapeutic monitoring of immunotherapeutic strategies in DLBCL.
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    Automated preparation of 2-[18F]fluoropropionate labeled peptides using a flexible, multi-stage synthesis platform (iPHASE Flexlab)
    Haskali, MB ; Roselt, PD ; Hicks, RJ ; Hutton, CA (WILEY, 2018-02)
    Radiolabelled peptides are vital tools used in positron emission tomography imaging for the diagnosis of disease, drug discovery, and biomedical research. Peptides are typically labeled through conjugation to a radiolabelled prosthetic group, which usually necessitates complex, multi-step procedures, especially for fluorine-18 labeled peptides. Herein, we describe the automated synthesis and formulation of 2-[18 F]fluoropropionate labeled RGD-peptides through use of the iPHASE Flexlab as an effective dual-stage radiochemical synthesis module. The fully automated preparation of the monomeric RGD-peptides, [18 F]FP-GalactoRGD and [18 F]FP-c(RGDy(SO3 )K), was accomplished in under 90 minutes with n.d.c. radiochemical yields ca. 7% from fluoride. Similarly, the automated preparation of the dimeric RGD-peptides, [18 F]F-PRGD2 and [18 F]FP-E(RGDy(SO3 )K)2 , was accomplished in under 105 minutes with n.d.c. yields ca. 4% from fluoride.