26 results on '"Balakrishnar B"'
Search Results
2. 213P Stage I seminoma testicular cancer: Predictors of relapse and outcomes for adjuvant carboplatin vs active surveillance
- Author
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Quah, G.T., primary, Espinoza, D., additional, Crumbaker, M., additional, Balakrishnar, B., additional, Arasaratnam, M., additional, Bariol, S., additional, Brooks, A., additional, Lau, H., additional, Patel, M., additional, and Gurney, H., additional
- Published
- 2020
- Full Text
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3. Patterns and trends in the incidence of paediatric and adult germ cell tumours in Australia, 1982–2011
- Author
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van Leeuwen, MT, Gurney, H, Turner, JJ, Turner, SL, Pearson, SA, Laaksonen, MA, Harnett, P, Balakrishnar, B, Sabanathan, D, Vajdic, CM, van Leeuwen, MT, Gurney, H, Turner, JJ, Turner, SL, Pearson, SA, Laaksonen, MA, Harnett, P, Balakrishnar, B, Sabanathan, D, and Vajdic, CM
- Abstract
Purpose Germ cell tumour (GCT) aetiology is uncertain and comprehensive epidemiological studies of GCT incidence are few. Methods Nationwide data on all malignant GCTs notified to Australian population-based cancer registries during 1982–2011 were obtained. Age- and sex-specific, and World age-standardised incidence rates were calculated for paediatric (0–14) and adult (15+) cases using the latest WHO subtype classification scheme. Temporal trends were examined using Joinpoint regression. Results There were 17,279 GCTs (552 paediatric, 16,727 adult). Age-specific incidence in males (all histologies combined) was bimodal, with peaks during infancy for most sites, and second, larger, peaks during young adulthood. Incidence of ovarian tumours peaked at age 15–19. Around half of paediatric tumours were extragonadal, whereas adult tumours were mostly gonadal. Yolk sac tumours and teratomas predominated in infants, whereas germinomas became more frequent towards adulthood. Increasing incidence trends for some adult gonadal tumours have stabilised; the trend for male extragonadal tumours is also declining. Conclusion Broad similarities in the shape of age-specific incidence curves, particularly for gonadal, central nervous system, and mediastinal tumours provide epidemiological support for commonalities in aetiology among clinically disparate GCT subtypes. Differences in peak ages reflect underlying subtype-specific biological differences. Declining incidence trends for some adult gonadal tumours accords with the global transition in GCT incidence, and supports the possibility of a reduction in prevalence of shared aetiological exposures.
- Published
- 2016
4. CONCOMITANT CYP2D6 INHIBITOR USE AND PLASMA METABOLITE LEVELS IN BREAST CANCER PATIENTS TREATED WITH TAMOXIFEN
- Author
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Fox, P., Balakrishnar, B., Menzies, A., Liddle, C., Coulter, S., Provan, P., Gebski, V., Hui, R., Richard Kefford, Wilcken, N., Balleine, R., and Howard Gurney
5. Sequential [ 177 Lu]Lu-PSMA-617 and docetaxel versus docetaxel in patients with metastatic hormone-sensitive prostate cancer (UpFrontPSMA): a multicentre, open-label, randomised, phase 2 study.
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Azad AA, Bressel M, Tan H, Voskoboynik M, Suder A, Weickhardt AJ, Guminski A, Francis RJ, Saghebi J, Dhiantravan N, Joshua AM, Emmett L, Horvath L, Murphy DG, Hsiao E, Balakrishnar B, Lin P, Redfern A, Macdonald W, Ng S, Lee ST, Pattison DA, Nadebaum D, Kirkwood ID, and Hofman MS
- Subjects
- Humans, Male, Aged, Middle Aged, Prostate-Specific Antigen blood, Radiopharmaceuticals therapeutic use, Radiopharmaceuticals administration & dosage, Radiopharmaceuticals adverse effects, Radioisotopes therapeutic use, Radioisotopes administration & dosage, Radioisotopes adverse effects, Docetaxel administration & dosage, Docetaxel therapeutic use, Lutetium therapeutic use, Dipeptides therapeutic use, Dipeptides adverse effects, Dipeptides administration & dosage, Heterocyclic Compounds, 1-Ring therapeutic use, Heterocyclic Compounds, 1-Ring administration & dosage, Heterocyclic Compounds, 1-Ring adverse effects, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Prostatic Neoplasms pathology, Prostatic Neoplasms drug therapy
- Abstract
Background: Lutetium-177 [
177 Lu]Lu-prostate-specific membrane antigen (PSMA)-617 improves survival and quality of life in patients with metastatic castration-resistant prostate cancer, but whether it confers a benefit in hormone-sensitive disease is unknown. We aimed to evaluate [177 Lu]Lu-PSMA-617 before docetaxel treatment in patients with de-novo high-volume metastatic hormone-sensitive prostate cancer., Methods: UpFrontPSMA was an investigator-initiated, multicentre, open-label, randomised, phase 2 trial done at 11 Australian hospitals. Eligible patients had prostate adenocarcinoma without clinically significant neuroendocrine differentiation or small-cell histology, were aged 18 years or older, had less than 4 weeks on androgen deprivation therapy, had an Eastern Cooperative Oncology Group performance status of 0-2, and had high-volume PSMA-avid disease on [68 Ga]Ga-PSMA-11 PET-CT with no major discordance on 2-[18 F] fluorodeoxyglucose-PET-CT. Patients were randomly assigned (1:1) to the experimental treatment ([177 Lu]Lu-PSMA-617 followed 6 weeks later by docetaxel) or standard-of-care treatment (docetaxel alone) using computer-based block randomisation with random block sizes, stratified by disease volume by conventional imaging and duration of androgen deprivation therapy at the time of registration. Neither patients nor investigators were masked to treatment assignment. Patients in the experimental group received two cycles of [177 Lu]Lu-PSMA-617 7·5 GBq every 6 weeks intravenously, followed 6 weeks later by six cycles of docetaxel 75 mg/m2 every 3 weeks intravenously, whereas patients in the standard-of-care treatment group received six cycles of docetaxel 75 mg/m2 every 3 weeks intravenously. All patients received continuous androgen deprivation therapy. The primary endpoint was undetectable prostate-specific antigen (≤0·2 ng/mL) at 48 weeks, assessed using a modified intention-to-treat analysis. The trial is registered with ClinicalTrials.gov, NCT04343885., Findings: Between May 5, 2020, and April 18, 2023, 130 patients were randomly assigned, 63 (48%) to [177 Lu]Lu-PSMA-617 plus docetaxel and 67 (52%) to docetaxel alone. All patients were male and no race or ethnicity data were collected. Median follow-up was 2·5 years (IQR 1·8-3·0). Four patients in the docetaxel alone group withdrew consent after randomisation and no data beyond screening were collected. An additional four patients were not evaluable for the primary endpoint at 48 weeks (two in each group). 25 (41%) of 61 patients (95% CI 30-54) in the [177 Lu]Lu-PSMA-617 plus docetaxel group had undetectable PSA at 48 weeks compared with ten (16%) of 61 patients (9-28) in the docetaxel alone group (OR 3·88, 95% CI 1·61-9·38; p=0·0020). The most common grade 3 or 4 treatment-related adverse events were febrile neutropenia (seven [11%] of 63 patients in the [177 Lu]Lu-PSMA-617 plus docetaxel group vs six [10%] of 63 patients in the docetaxel alone group) and diarrhoea (four [6%] of 63 patients vs none). Serious adverse events occurred in 16 (25%) patients in the [177 Lu]Lu-PSMA-617 plus docetaxel group (none were definitely related to [177 Lu]Lu-PSMA-617) and 16 (25%) patients in the docetaxel alone group. No treatment-related deaths occurred., Interpretation: [177 Lu]Lu-PSMA-617 followed by docetaxel improved antitumour activity in patients with de-novo high-volume metastatic hormone-sensitive prostate cancer compared with docetaxel alone, without increased toxic effects. Our data potentially support a role for [177 Lu]Lu-PSMA-617 in metastatic hormone-sensitive prostate cancer., Funding: Prostate Cancer Research Alliance (Movember Foundation and Australian Government Medical Research Future Fund), US Department of Defence Impact Award-Clinical Trials, Endocyte/Advanced Accelerator Applications (a Novartis company), Australian Nuclear Science and Technology Organization, Victorian Cancer Agency, University of Melbourne, and Peter MacCallum Cancer Foundation., Competing Interests: Declaration of interests AAA reports grants from Aptevo Therapeutics (institutional), Astellas (investigator), Astellas (institutional), AstraZeneca (institutional), AstraZeneca (investigator), Bionomics (institutional), Bristol Myers Squibb (institutional), Eli Lilly (institutional), Exelixis (institutional), Gilead Sciences (institutional), GlaxoSmithKline (institutional), Hinova (institutional), Ipsen (institutional), Janssen (institutional), MedImmune (institutional), Merck Serono (investigator), Merck Serono (institutional), Merck Sharpe & Dohme (institutional), Novartis (institutional), Pfizer (institutional), Sanofi Aventis (institutional), and SYNthorx (institutional); consulting fees from Astellas, Novartis, Janssen, Sanofi, AstraZeneca, Bristol Myers Squibb, Tolmar, Telix Pharma, Merck, Bayer, Ipsen, Merck Serono, Amgen, and Noxopharm; honoraria from Janssen, Astellas, Novartis, Tolmar, Amgen, Pfizer, Bayer, Telix Pharma, Bristol Myers Squibb, Merck Serono, AstraZeneca, Sanofi, Ipsen, Merck Sharp & Dohme, Noxopharm, Daiichi Sankyo, and Arvinas; speakers' bureau fees from Astellas, Novartis, Amgen, Bayer, Janssen, Ipsen, Bristol Myers Squibb, and Merck Serono; support for attending meetings from Amgen, Astellas, Bayer, Hinova, Janssen, Merck Serono, Novartis, Pfizer, and Tolmar; participation on data safety monitoring or advisory boards for Arvinas, Astellas, Novartis, Janssen, Sanofi, AstraZeneca, Bristol Myers Squibb, Tolmar, Telix Pharma, Merck Sharpe & Dohme, Bayer, Ipsen, Merck Serono, Amgen, Noxopharm, and Daiichi Sankyo. MV reports personal fees from AstraZeneca and Merck Sharpe & Dohme and grants (to their institution) from AstraZeneca, Merck Sharpe & Dohme, Alpine Immune Sciences, Virocure, Hinova, Atridia/Hengrui, Antengene, and Biogene. AJW declares grants to their institution from Merck Sharpe & Dohme; consulting fees from Merck Sharpe & Dohme, Bayer, Bristol Myers Squibb, Pfizer, Ipsen, and Astellas; honoraria from Astellas and Bristol Myers Squibb; and support for attending meetings from Bayer. AG reports grants from Sun Pharma; consulting fees from Regeneron and Bayer; support to attend meetings from Sun Pharma and Bristol Myers Squibb; and participation in a data safety monitoring or advisory board for Regeneron and Bayer. RJF reports committee involvement in the Australasian Radiopharmaceutical Trials Network (unpaid). LE reports research grant support (to their institution) from Novartis and Clarity Pharma; consulting fees for lectures or advisory boards from Astellas, Janssen, AstraZeneca, Clarity, Novartis, and Telix in the past 5 years; and philanthropic grant support from the Prostate Cancer Foundation, St Vincent's Clinic Research Foundation, and the Curran Foundation. DGM has received reimbursement for advisory board or speaker bureau activity from the following companies (in the past 36 months): Janssen, Astellas, Bayer, AstraZeneca, Mundipharma, Novartis, and Ipsen. AR has received reimbursement for advisory board or speaker bureau activity from the following companies: AstraZeneca, Daiichi Sankyo, Lily, Pfizer, Merck Sharpe & Dohme, Roche, and Novartis. DAP reports personal fees from Eisai. MSH reports grants and receipt of equipment, materials, drugs, medical writing, gifts, or other services from the Prostate Cancer Foundation, NHRMC, Movember, US Department of Defense, Medical Research Future Fund, Bayer, Peter MacCallum Foundation, Isotopia, and the Australian Nuclear Science and Technology Organisation; consulting fees from Merck Sharp & Dohme and Novartis; honoraria from Janssen, Novartis, and AstraZeneca; and support for meetings from Merck Sharp & Dohme, Novartis, Janssen, AstraZeneca, and Astellas. All other authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.)- Published
- 2024
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6. Adherence Outcomes and Risk Factors Predicting Nonadherence to Active Surveillance in Patients With Stage 1 Testicular Germ Cell Tumors.
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Liang R, Adams D, Roncolato F, Asghari R, Descallar J, Pal A, Chua W, and Balakrishnar B
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- Humans, Male, Retrospective Studies, Adult, Risk Factors, Watchful Waiting statistics & numerical data, Middle Aged, Neoplasm Recurrence, Local psychology, Neoplasm Staging, Australia, Young Adult, Testicular Neoplasms psychology, Testicular Neoplasms pathology, Neoplasms, Germ Cell and Embryonal psychology, Patient Compliance statistics & numerical data
- Abstract
Purpose: Adherence to active surveillance in patients with stage 1 testicular cancers may be influenced by factors affecting capacity and motivation to attend appointments. The aims of this study were to assess adherence to active surveillance and analyze factors which may impact adherence., Patients and Methods: A retrospective cohort study was conducted in patients diagnosed with stage 1 testicular cancer between 2005 and 2020, and managed with active surveillance at 3 institutions in South Western Sydney, Australia. Adherence with active surveillance was followed to 2023 and patients were subsequently classified into 3 groups: "Optimal," "Adequate" or "Loss to follow-up" (LTFU). Factors for adherence were analyzed using multivariable logistic regression. Disease recurrence was analyzed using multivariable Cox regression., Results: In 125 patients, adherence with active surveillance was assessed as "Optimal" in 64 (51%), "Adequate" in 14 (11%), and LTFU in 47 (38%). Multivariable analysis demonstrated that patients had higher odds of being in the "Optimal" or "Adequate" categories if they were from a culturally and linguistically diverse background (OR 4.86, P = .026), nonsmokers (OR 7.63, P = .0002), not employed (OR 4.93, P = .0085), had a partner (OR 2.74, P = .0326), or were diagnosed after June 2016 (OR 5.22, P = .0016). Recurrence occurred in 21 patients (17%). The risk of recurrence increased with the presence of multiple pathological risk factors (HR 5.77, P = .0032), if patients were unemployed (HR 2.57, P = .032), or if they had "Optimal" or "Adequate" adherence (HR 12.74, P = .0136)., Conclusion: Adherence with active surveillance was poorer in this cohort of stage 1 testicular cancer patients. Patients from culturally and linguistically diverse backgrounds and those who were nonsmokers, unemployed, with a partner, and later date of diagnosis, were more likely to be adherent with active surveillance., Competing Interests: Disclosure None., (Crown Copyright © 2024. Published by Elsevier Inc. All rights reserved.)
- Published
- 2024
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7. Review of Toxicities of PARP Inhibitors in Metastatic Castrate Resistant Prostate Cancer.
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Nindra U, Hong JH, Balakrishnar B, Pal A, and Chua W
- Subjects
- Male, Humans, Poly(ADP-ribose) Polymerase Inhibitors adverse effects, Patient Selection, Phthalazines adverse effects, Prostatic Neoplasms, Castration-Resistant drug therapy, Anemia chemically induced
- Abstract
There is emerging evidence for the use of poly (ADP-ribose) polymerase inhibitors (PARPi) in patients with mCRPC with patients harboring germline or somatic mutations deriving clinical benefit. However, the toxicity profile of PARPi in mCRPC is not well established. In March 2022 a literature search was conducted across 4 databases - Medline, PubMed, Cochrane Library and Embase. In total, 14 relevant studies were identified cumulating in 2066 patients that were treated with PARPi. The overall ORR to PARPi alone or in combination with other therapy was 37% (246/666). In 5trials that investigated PARPi alone, the ORR was 39% (141/361). Treatment emergent adverse events (TEAEs) of any grade were reported in 96% (1034/1080) in PARPi treatment arms. TEAEs of grade >= 3 were reported in 57% (611/1080). 45% (457/1006) experienced treatment interruption whilst 31% (310/989) required dose reductions. 11% (114/1006) of patients had their treatment discontinued directly as the result of toxicity associated with the trial medications. The most common hematological toxicity was anemia, reported in 490/1160 (42%) patients. and lowered white blood cell count were the next 2most common toxicities, reported in 186/655 (28%) and 133/729 (18%) respectively. The 3most common non-hematological toxicities reported were nausea, fatigue and anorexia reported in 440/1013 (43%), 340/1013 (34%) and 274/1013 (27%) patients respectively. Overall, TRAEs associated with individual PARPi are still emerging with hematological toxicities being most apparent. Further toxicities will be informed from future clinical trials to allow improved treatment selection, education and management of toxicities in prostate cancer., (Copyright © 2022. Published by Elsevier Inc.)
- Published
- 2023
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8. A Rare Case of Castrate-Resistant Prostate Adenocarcinoma with a Unilateral Testicular Metastasis Mimicking a Primary Testicular Tumour.
- Author
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Hong JH, Nindra U, Nguyen R, Gassner P, Balakrishnar B, and Rutland T
- Abstract
Prostate adenocarcinoma with testicular metastasis is rare, present in up to 4% of autopsy diagnoses, and presents symptomatically in less than 0.5% of cases. We report an unusual case of a 55-year-old male who developed a symptomatic testicular metastasis from primary prostate cancer 4 years after initial diagnosis of metastatic castrate-sensitive prostate cancer with nodal and bone-only involvement. The patient had orchidectomy, histologically confirming the metastasis and revealing sparing of the spermatic cord. Prior treatment for his metastatic castrate-sensitive prostate cancer had included androgen deprivation therapy and upfront docetaxel chemotherapy. He had received palliative radiotherapy for symptomatic bone metastasis and managed on enzalutamide for castrate-resistant disease for the preceding 22 months with ongoing PSA response at the time of diagnosis of new testicular metastasis, with a further significant PSA response following his "testicular metastasectomy." At the time of diagnosis of testicular metastasis, he did not have any evidence of other visceral metastases, and his metastatic disease otherwise remained radiologically stable. We describe his disease course, treatment and outline the rare nature of his case of testicular metastasis from prostate cancer., Competing Interests: The authors have no conflicts of interest to declare., (© 2022 The Author(s). Published by S. Karger AG, Basel.)
- Published
- 2022
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9. Choice of antibody is critical for specific and sensitive detection of androgen receptor splice variant-7 in circulating tumor cells.
- Author
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Khan T, Lock JG, Ma Y, Harman DG, de Souza P, Chua W, Balakrishnar B, Scott KF, and Becker TM
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- Cell Count, Humans, Male, Protein Isoforms genetics, Protein Isoforms metabolism, Receptors, Androgen genetics, Receptors, Androgen metabolism, Neoplastic Cells, Circulating pathology, Prostatic Neoplasms, Castration-Resistant diagnosis, Prostatic Neoplasms, Castration-Resistant drug therapy, Prostatic Neoplasms, Castration-Resistant genetics
- Abstract
Androgen receptor variant 7 (AR-V7) is an important biomarker to guide treatment options for castration-resistant prostate cancer (CRPC) patients. Its detectability in circulating tumour cells (CTCs) opens non-invasive diagnostic avenues. While detectable at the transcript level, AR-V7 protein detection in CTCs may add additional information and clinical relevance. The aim of this study was to compare commercially available anti-AR-V7 antibodies and establish reliable AR-V7 immunocytostaining applicable to CTCs from prostate cancer (PCa) patients. We compared seven AR-V7 antibodies by western blotting and immmunocytostaining using a set of PCa cell lines with known AR/AR-V7 status. The emerging best antibody was validated for detection of CRPC patient CTCs enriched by negative depletion of leucocytes. The anti-AR-V7 antibody, clone E308L emerged as the best antibody in regard to signal to noise ratio with a specific nuclear signal. Moreover, this antibody detects CRPC CTCs more efficiently compared to an antibody previously shown to detect AR-V7 CTCs. We have determined the best antibody for AR-V7 detection of CTCs, which will open future studies to correlate AR-V7 subcellular localization and potential co-localization with other proteins and cellular structures to patient outcomes., (© 2022. The Author(s).)
- Published
- 2022
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10. Patterns of care and outcomes of men with germ cell tumors in a high-volume Australian center.
- Author
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Arasaratnam M, Balakrishnar B, Crumbaker M, Turner S, Hayden AJ, Brooks A, Patel MI, Lau H, Woo H, Bariol S, and Gurney H
- Subjects
- Adult, Australia epidemiology, Humans, Male, Retrospective Studies, Neoplasms, Germ Cell and Embryonal epidemiology, Neoplasms, Germ Cell and Embryonal therapy, Seminoma diagnosis, Seminoma epidemiology, Seminoma therapy, Testicular Neoplasms diagnosis, Testicular Neoplasms epidemiology, Testicular Neoplasms therapy
- Abstract
Aim: To evaluate disease presentation, treatment practices, and outcomes of patients with germ cell tumor (GCT) treated in a high-volume cancer center in Australia., Methods: This is a retrospective analysis of 609 patients diagnosed with GCT in the Sydney West Cancer Network between 1990 and 2013. Cause and date of death, and second malignancy information was sourced from The Centre for Health Record Linkage., Results: The median age was 33 years (range, 14-85). Primary site was testis in 590 (96.9%), mediastinum in nine (1.5%), and retroperitoneum in nine (1.5%). History of undescended testis was present in 48 (7.9%). Pure seminoma was seen in 334 (54.8%), with 274 (82.0%) being stage I. There was a decline in use of adjuvant radiotherapy from 83% in 1990-1997 to 29% in 2006-2013. Nonseminoma GCT (NSGCT) was diagnosed in 275 (45.2%), with 162 (58.9%) being stage 1. Active surveillance has increased as the initial treatment, from 58% between 1990 and 1997 to 89% between 2006 and 2013. Metastatic disease at presentation was seen in 162 (26.6%): 55 (34.0%) seminoma and 107 (66.0%) NSGCT. With median of 15-year follow-up, 18 (3.0%) have died from GCT and 70 (11.5%) from all causes. Ten-year overall survival was 93% and GCT-specific survival was 97%. Forty patients developed a secondary malignancy, with 38 receiving chemotherapy, radiotherapy, or both., Conclusions: This large Australian series illustrates a changing pattern of care and outcomes and compares them favorably with other series. This serves as a basis for future comparison of outcomes for this malignancy., (© 2021 John Wiley & Sons Australia, Ltd.)
- Published
- 2022
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11. Biomarkers of Castrate Resistance in Prostate Cancer: Androgen Receptor Amplification and T877A Mutation Detection by Multiplex Droplet Digital PCR.
- Author
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Young FP, Becker TM, Nimir M, Opperman T, Chua W, Balakrishnar B, de Souza P, and Ma Y
- Abstract
Androgen Receptor (AR) alterations (amplification, point mutations, and splice variants) are master players in metastatic castration resistant prostate cancer (CRPC) progression and central therapeutic targets for patient management. Here, we have developed two multiplexed droplet digital PCR (ddPCR) assays to detect AR copy number (CN) and the key point mutation T877A. Overcoming challenges of determining gene amplification from liquid biopsies, these assays cross-validate each other to produce reliable AR amplification and mutation data from plasma cell free DNA (cfDNA) of advanced prostate cancer (PC) patients. Analyzing a mixed PC patient cohort consisting of CRPC and hormone sensitive prostate cancer (HSPC) patients showed that 19% (9/47) patients had AR CN amplification. As expected, only CRPC patients were positive for AR amplification, while interestingly the T877A mutation was identified in two patients still considered HSPC at the time. The ddPCR based analysis of AR alterations in cfDNA is highly economic, feasible, and informative to provide biomarker detection that may help to decide on the best follow-up therapy for CRPC patients.
- Published
- 2022
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12. Single-Cell Analysis of BRAF V600E and NRAS Q61R Mutation Status in Melanoma Cell Lines as Method Generation for Circulating Melanoma Cells.
- Author
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Po JW, Ma Y, Luk AWS, Lynch D, Balakrishnar B, Brungs D, Azimi F, Cooper A, Saricilar E, Murthy V, de Souza P, and Becker TM
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- Amino Acid Substitution, Cell Line, Tumor, Humans, Melanoma pathology, GTP Phosphohydrolases genetics, Melanoma genetics, Membrane Proteins genetics, Mutation, Missense, Neoplastic Cells, Circulating, Proto-Oncogene Proteins B-raf genetics, Single-Cell Analysis
- Abstract
Molecular testing of tumor biopsies allows for the identification of the key mutations driving a patient's cancer. However, this is limited to singular nodes and may not accurately reflect cancer heterogeneity. Circulating tumor cell (CTC) analyses offer a noninvasive method of interrogating the genomic profile of patient-derived tumor material. To date, molecular analysis of CTCs has relied on the characterization of bulk or pooled CTC lysates, limiting the detection of minor tumorigenic CTC subclones. Here, we show a workflow enabling BRAF
V600E /NRASQ61R mutation detection from single cultured melanoma cells by combining micromanipulation and genomic material amplification methods. This workflow can be directly integrated into circulating tumor cell analysis applications.- Published
- 2021
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13. PD-L1 Detection on Circulating Melanoma Cells.
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Po JW, Ma Y, Balakrishnar B, Brungs D, Azimi F, Cooper A, Saricilar E, Murthy V, de Souza P, and Becker TM
- Subjects
- Antibodies immunology, B7-H1 Antigen immunology, Humans, Leukocytes, Mononuclear cytology, Liquid Biopsy methods, Melanoma diagnosis, B7-H1 Antigen metabolism, Immune Checkpoint Inhibitors pharmacology, Immunomagnetic Separation methods, Melanoma blood, Neoplastic Cells, Circulating immunology
- Abstract
The advent of personalized medicines targeting cell signaling pathways has radically improved melanoma patient outcomes. More recently, immune-modulating therapies disrupting the PD-1/PD-L1 axis have become a powerful tool in the treatment of a range of melanoma, showing a profound improvement in the overall survival outcomes. However, immune checkpoint inhibitors (ICIs) are associated with considerable toxicities and appear to only be efficacious in a subset of melanoma patients. Therefore, there is an urgent need to identify biomarkers that can determine if patients will or will not respond to ICI therapy. Here, we describe an optimized method for analyzing PD-L1 expression on circulating melanoma cells following immunomagnetic enrichment from patient blood samples.
- Published
- 2021
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14. Simplified phenotyping of CYP2D6 for tamoxifen treatment using the N-desmethyl-tamoxifen/ endoxifen ratio.
- Author
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Lee CI, Low SK, Maldonado R, Fox P, Balakrishnar B, Coulter S, de Bruijn P, Koolen SLW, Gao B, Lynch J, Zdenkowski N, Hui R, Liddle C, Mathijssen RHJ, Wilcken N, Wong M, and Gurney H
- Subjects
- Adult, Aged, Alleles, Breast Neoplasms blood, Breast Neoplasms drug therapy, Cytochrome P-450 CYP2D6 genetics, Drug Monitoring methods, Female, Genotype, Humans, Middle Aged, Phenotype, Polymorphism, Single Nucleotide, Prospective Studies, Retrospective Studies, Tamoxifen blood, Antineoplastic Agents, Hormonal therapeutic use, Breast Neoplasms genetics, Cytochrome P-450 CYP2D6 classification, Tamoxifen analogs & derivatives, Tamoxifen therapeutic use
- Abstract
Introduction: CYP2D6 protein activity can be inferred from the ratio of N-desmethyl-tamoxifen (NDMT) to endoxifen (E). CYP2D6 polymorphisms are common and can affect CYP2D6 protein activity and E level. Some retrospective studies indicate that E < 16 nM may relate to worse outcome., Materials and Methods: A target NDMT/E ratio was defined as associated with an E level of 15 nM in the 161 patient Test cohort of tamoxifen-treated patients, dichotomizing them into 'Normal' (NM) and 'Slow' (SM) CYP2D6 metabolizer groups. This ratio was then tested on a validation cohort of 52 patients. Patients were phenotyped based on the standard method (ultrarapid/extensive, intermediate or poor metabolizers; UM/EM, IM, PM) or a simplified system based on whether any variant allele (V) vs wildtype (wt) was present (wt/wt, wt/V, V/V). Comprehensive CYP2D6 genotyping was undertaken on germline DNA., Results: A target NDMT/E ratio of 35 correlated with the 15 nM E level, dichotomizing patients into NM (<35; N = 117) and SM (>35; N = 44) groups. The ratio was independently validated by a validation cohort. The simplified system was better in predicting patients without slow metabolism, with specificity and sensitivity of 96% and 44% respectively, compared with the standard method - sensitivity 81% and specificity 83%., Conclusions: The simplified classification system based on whether any variant was present better identified patients who were truly not CYP2D6 slow metabolizers more accurately than the current system. However, as CYP2D6 genotype is not the only determinant of endoxifen level, we recommend that direct measurement of endoxifen should also be considered., Competing Interests: Declaration of competing interest Clara Inkyung Lee, Peter Fox, Bavanthi Balakrishnar, Bo Gao, Sally Coulter, Christopher Liddle, Mark Wong, and Nicholas Wilcken have no conflicts of interest to declare. Rina Hui has conflicts to declare including: Advisory board member for Merck Sharp and Dohme, Astra Zeneca, Novartis, Roche and Bristol-Myers Squib, speaker honorarium for Merk Sharp and Dohme. Howard Gurney has conflicts to declare including: Advisory board/consulting role for Bristol-Myers Squib, Ipsen, Merck Sharp and Dohme, Astra Zeneca, Janssen-Cilag. Honorarium for Pfizer. Ron H.J. Mathijssen has conflicts to declare including: Speakers’ Bureau: Novartis. Research Funding: Roche (Inst), Sanofi (Inst), Astellas Pharma (Inst), Bayer Holding (Inst), Boehringer Ingelheim (Inst), Pfizer (Inst), Cristal Therapeutics (Inst), Pamgene (Inst). Travel, Accommodations, Expenses: Pfizer, Astellas Pharma. Stijn L.W. Koolen has conflicts to declare including: Speakers’ Bureau: Novartis, Pfizer, Research Funding: Cristal Therapeutics (Inst), Novartis (Inst), Travel, Accommodations, Expenses: Ipsen., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2020
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15. Endocrine Resistance in Breast Cancer: The Role of Estrogen Receptor Stability.
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Jeffreys SA, Powter B, Balakrishnar B, Mok K, Soon P, Franken A, Neubauer H, de Souza P, and Becker TM
- Subjects
- Female, Humans, Breast Neoplasms genetics, Drug Resistance, Neoplasm genetics, Protein Processing, Post-Translational genetics, Receptors, Estrogen genetics
- Abstract
Therapy of hormone receptor positive breast cancer (BCa) generally targets estrogen receptor (ER) function and signaling by reducing estrogen production or by blocking its interaction with the ER. Despite good long-term responses, resistance to treatment remains a significant issue, with approximately 40% of BCa patients developing resistance to ET. Mutations in the gene encoding ERα, ESR1 , have been identified in BCa patients and are implicated as drivers of resistance and disease recurrence. Understanding the molecular consequences of these mutations on ER protein levels and its activity, which is tightly regulated, is vital. ER activity is in part controlled via its short protein half-life and therefore changes to its stability, either through mutations or alterations in pathways involved in protein stability, may play a role in therapy resistance. Understanding these connections and how ESR1 alterations could affect protein stability may identify novel biomarkers of resistance. This review explores the current reported data regarding posttranslational modifications (PTMs) of the ER and the potential impact of known resistance associated ESR1 mutations on ER regulation by affecting these PTMs in the context of ET resistance.
- Published
- 2020
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16. Tamoxifen-induced severe hot flashes and endoxifen levels: is dose reduction a safe and effective strategy?
- Author
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Lee CI, Fox P, Balakrishnar B, Balleine RL, Gao B, Provan P, Coulter S, Liddle C, Hui R, Wong M, Gurney H, and Wilcken N
- Subjects
- Adult, Antineoplastic Agents, Hormonal administration & dosage, Breast Neoplasms genetics, Cytochrome P-450 CYP2D6, Dose-Response Relationship, Drug, Female, Genotype, Humans, Middle Aged, Tamoxifen administration & dosage, Tamoxifen blood, Treatment Outcome, Antineoplastic Agents, Hormonal adverse effects, Breast Neoplasms drug therapy, Hot Flashes chemically induced, Tamoxifen adverse effects, Tamoxifen analogs & derivatives
- Abstract
Objectives: Severe hot flash (HF) toxicity due to tamoxifen can compromise compliance. We previously found that HFs did not correlate with endoxifen level or CYP2D6 genotype. In this study, we reduced tamoxifen dose in patients with severe HFs to determine whether HFs were ameliorated whilst maintaining a purported therapeutic endoxifen level of >15 nM., Materials and Methods: Twenty patients with severe HFs on 20 mg TAM had CYP2D6genotype, trough level tamoxifen and metabolites measured with Loprinzi HF scores (HFS) derived before and after DR of tamoxifen to 10 mg. Other data collected included demographics, smoking, alcohol, menstrual and breast cancer history, previous chemotherapies, concurrent medications, BMI and other tamoxifen toxicities., Results: At the 20 mg tamoxifen dose, endoxifen levels were 25.6, 0-91.9 nM (median, range) with HFS 131, 22-1482 (median, range). Upon DR to 10 mg, median endoxifen level fell to 14.1, 0.6-71.9 nM (difference in means p = 0.11, two-tailed T test) with HFS 47, 5-864 (difference in means p = 0.24, two-tailed T test). Despite lacking statistical significance, 85% of patients reported subjective improvement of HFs with DR. After DR, the proportion of patients with endoxifen level <15 nM increased from 20% to 50%. HFS did not correlate with any other parameter., Conclusion: DR of tamoxifen from 20 mg to 10 mg daily resulted in halving of endoxifen levels and subjective improvement of HF. While half the dose-reduced patients were below a potential therapeutic level of endoxifen, other recent studies suggest that low endoxifen levels may not indicate reduced effectiveness of tamoxifen., (Copyright © 2019 Elsevier Ltd. All rights reserved.)
- Published
- 2019
- Full Text
- View/download PDF
17. Patterns of immunotherapy use and management of toxicities in regional and tertiary settings.
- Author
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Hamilton B, Xu K, Honeyball F, Balakrishnar B, and Zielinski R
- Subjects
- Adult, Aged, Aged, 80 and over, Antibodies, Monoclonal, Humanized adverse effects, Antineoplastic Agents, Immunological adverse effects, CTLA-4 Antigen antagonists & inhibitors, Drug-Related Side Effects and Adverse Reactions epidemiology, Female, Humans, Immunotherapy adverse effects, Male, Melanoma secondary, Middle Aged, Neoplasm Staging, Oncology Service, Hospital, Programmed Cell Death 1 Receptor antagonists & inhibitors, Retrospective Studies, Skin Neoplasms secondary, Tertiary Care Centers, Melanoma, Cutaneous Malignant, Antibodies, Monoclonal, Humanized therapeutic use, Antineoplastic Agents, Immunological therapeutic use, Carcinoma, Non-Small-Cell Lung drug therapy, Immunotherapy methods, Lung Neoplasms drug therapy
- Abstract
Background: The introduction of the cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and programmed cell death protein 1 (PD-1) immune checkpoint inhibitors and their subsequent listing on the Pharmaceutical Benefits Scheme for use in metastatic melanomas, renal cell carcinomas and non-small-cell lung cancers has resulted in routine use of these agents in oncology practices, including in regional areas. Although immunotherapeutic agents generally have a favourable toxicity profile compared to chemotherapy, they can provoke immune-related adverse effects (irAE) caused by an unregulated and hyperstimulated immune response. Some of these effects can be serious and life-threatening., Aims: To compare the utilisation of immunotherapy and the rates, management and outcomes of irAE between a regional oncology service and a tertiary service., Methods: We reviewed the medical records for all patients treated with immunotherapy in the participating services for the 5-year period from 31 July 2012 to 31 July 2017., Results: Data demonstrated that rates of immunotherapy use are both similar and increasing across the tertiary and regional services. The rates, types and severity of irAE are equivalent and in concordance with pre-existing literature. Immune-related adverse events appear to be identified and treated earlier in the regional service with the corresponding reduction in the duration of immunosuppression and requirement for inpatient management., Conclusion: The use of immunotherapy in a regional setting is safe and equivalent to that of a tertiary centre., (© 2019 Royal Australasian College of Physicians.)
- Published
- 2019
- Full Text
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18. Detection of AR-V7 in Liquid Biopsies of Castrate Resistant Prostate Cancer Patients: A Comparison of AR-V7 Analysis in Circulating Tumor Cells, Circulating Tumor RNA and Exosomes.
- Author
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Nimir M, Ma Y, Jeffreys SA, Opperman T, Young F, Khan T, Ding P, Chua W, Balakrishnar B, Cooper A, De Souza P, and Becker TM
- Subjects
- Aged, Aged, 80 and over, Alternative Splicing, Biomarkers, Tumor genetics, Cell-Free Nucleic Acids, Exosomes, Humans, Liquid Biopsy methods, Male, Middle Aged, Prostatic Neoplasms, Castration-Resistant blood, Prostatic Neoplasms, Castration-Resistant pathology, Protein Isoforms blood, Protein Isoforms genetics, RNA, Neoplasm blood, RNA, Neoplasm genetics, Receptors, Androgen genetics, Sensitivity and Specificity, Biomarkers, Tumor blood, Neoplastic Cells, Circulating chemistry, Prostatic Neoplasms, Castration-Resistant diagnosis, Receptors, Androgen blood
- Abstract
Detection of androgen receptor (AR) variant 7 (AR-V7) is emerging as a clinically important biomarker in castrate resistant prostate cancer (CRPC). Detection is possible from tumor tissue, which is often inaccessible in the advanced disease setting. With recent progress in detecting AR-V7 in circulating tumor cells (CTCs), circulating tumor RNA (ctRNA) and exosomes from prostate cancer patients, liquid biopsies have emerged as an alternative to tumor biopsy. Therefore, it is important to clarify whether these approaches differ in sensitivity in order to achieve the best possible biomarker characterization for the patient. In this study, blood samples from 44 prostate cancer patients were processed for CTCs and ctRNA with subsequent AR-V7 testing, while exosomal RNA was isolated from 16 samples and tested. Detection of AR and AR-V7 was performed using a highly sensitive droplet digital PCR-based assay. AR and AR-V7 RNA were detectable in CTCs, ctRNA and exosome samples. AR-V7 detection from CTCs showed higher sensitivity and has proven specificity compared to detection from ctRNA and exosomes. Considering that CTCs are almost always present in the advanced prostate cancer setting, CTC samples should be considered the liquid biopsy of choice for the detection of this clinically important biomarker.
- Published
- 2019
- Full Text
- View/download PDF
19. Patterns of Presentation and Treatment Outcomes of Non-clear-cell Renal Cell Carcinoma and Sarcomatoid Renal Cell Carcinoma Patients in 2 Tertiary Referral Centers in Sydney, Australia.
- Author
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Naher S, Padinharakam S, Balakrishnar B, Chua W, Descallar J, Adams D, de Souza P, Harrison M, and Lim S
- Subjects
- Adult, Aged, Aged, 80 and over, Australia, Carcinoma, Renal Cell mortality, Carcinoma, Renal Cell therapy, Cohort Studies, Female, Humans, Kidney Neoplasms mortality, Kidney Neoplasms therapy, Male, Middle Aged, Neoplasm Recurrence, Local mortality, Neoplasm Recurrence, Local therapy, Survival Analysis, Tertiary Care Centers, Treatment Outcome, Young Adult, Carcinoma, Renal Cell epidemiology, Kidney Neoplasms epidemiology, Neoplasm Recurrence, Local epidemiology
- Abstract
Background: Non-clear-cell renal cell carcinoma (nccRCC) and renal cell carcinoma with sarcomatoid features (scRCC) are rare, and represent subtypes with less defined treatment strategies. The aim of this study is to describe the patterns of care and outcomes of these patients in 2 tertiary referral centers in South Western Sydney Local Health District over a 10-year period., Patients and Methods: Patients with RCC seen at South Western Sydney Local Health District from January 1, 2005 to December 31, 2015 were identified from electronic medical records. For each patient, we extracted details regarding demographics, tumor characteristics, treatment, recurrences, and survival, which was analyzed using the Kaplan-Meier method., Results: Of 178 patients with RCC identified between 2005 and 2015, 23% (n = 41) had nccRCC and 8% (n = 15) had scRCC. Twenty-five patients in total had de novo metastatic disease or disease recurrence. The median follow-up was 46 and 16 months for nccRCC and scRCC, respectively. The median overall survival for nccRCC with metastatic disease was 34 months (range, 14 months to not reached). Seventy percent of these patients received systemic therapy. By contrast, the median overall survival for scRCC with metastatic disease was 10 months (range, 1.6-89 months). Less than one-half of the patients with scRCC received systemic therapy in our cohort, with only 34% receiving no more than 1 line of treatment., Conclusions: Our data confirm the rapid and aggressive course of scRCC, highlighting the need for more effective therapeutic strategies in this rare patient population., (Copyright © 2019 Elsevier Inc. All rights reserved.)
- Published
- 2019
- Full Text
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20. Dose individualization of sunitinib in metastatic renal cell cancer: toxicity-adjusted dose or therapeutic drug monitoring.
- Author
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Sabanathan D, Zhang A, Fox P, Coulter S, Gebski V, Balakrishnar B, Chan M, Liddle C, and Gurney H
- Subjects
- Adult, Aged, Antineoplastic Agents adverse effects, Antineoplastic Agents pharmacokinetics, Carcinoma, Renal Cell pathology, Dose-Response Relationship, Drug, Female, Humans, Indoles adverse effects, Indoles pharmacokinetics, Kidney Neoplasms pathology, Male, Middle Aged, Neoplasm Metastasis, Prospective Studies, Pyrroles adverse effects, Pyrroles pharmacokinetics, Sunitinib, Survival Rate, Time Factors, Antineoplastic Agents administration & dosage, Carcinoma, Renal Cell drug therapy, Drug Monitoring methods, Indoles administration & dosage, Kidney Neoplasms drug therapy, Pyrroles administration & dosage
- Abstract
Purpose: Dose individualization of sunitinib has been proposed using therapeutic drug monitoring (TDM) or toxicity-adjusted dose (TAD). We prospectively studied aspects of TDM and TAD to inform future trials, namely (1) intrapatient variability (CV) of sunitinib and (2) feasibility of a TAD protocol., Methods: Sunitinib dose was adjusted to ensure grade 1 or 2 toxicity on 10-20 days of each 42-day cycle. Total trough levels (TTL) C
min of sunitinib and its active metabolite were measured every 6 weeks., Results: In 45 patients with mRCC, 283 TTL samples were assayed over a median 30 weeks (6-108 weeks). Fifteen patients (33%) had an intrapatient CV of >25% in TTL. Ninety-one percent achieved target toxicity with a final sunitinib dose of 25 mg (18%), 37.5 mg (27%), 50 mg (50%), and 62.5 or 75 mg (7%). TTL Cmin was <50, 50-100, and >100 ng/mL in 7 (15%), 31 (69%), and 7 patients (15.5%), respectively. The median overall survival was 32 months., Conclusions: Sunitinib level has minimal variability in the majority of patients on stable dose. A subset of patients had a significant intrapatient variation, so we recommend two samples 4 to 6 months apart. TAD is feasible for dosing sunitinib and showed a favourable outcome.- Published
- 2017
- Full Text
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21. CTC-mRNA (AR-V7) Analysis from Blood Samples-Impact of Blood Collection Tube and Storage Time.
- Author
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Luk AWS, Ma Y, Ding PN, Young FP, Chua W, Balakrishnar B, Dransfield DT, Souza P, and Becker TM
- Subjects
- Biomarkers, Tumor standards, Blood Preservation instrumentation, Blood Preservation standards, Blood Specimen Collection instrumentation, Blood Specimen Collection standards, Case-Control Studies, Cell Line, Tumor, Citrates chemistry, Edetic Acid chemistry, Epithelial Cell Adhesion Molecule blood, Female, Humans, Male, Neoplastic Cells, Circulating metabolism, Plastics adverse effects, Plastics chemistry, Prostatic Neoplasms blood, Time Factors, Biomarkers, Tumor blood, Blood Preservation adverse effects, Blood Specimen Collection adverse effects, Disposable Equipment standards, Receptors, Androgen blood
- Abstract
Circulating tumour cells (CTCs) are an emerging resource for monitoring cancer biomarkers. New technologies for CTC isolation and biomarker detection are increasingly sensitive, however, the ideal blood storage conditions to preserve CTC-specific mRNA biomarkers remains undetermined. Here we tested the preservation of tumour cells and CTC-mRNA over time in common anticoagulant ethylene-diamine-tetra-acetic acid (EDTA) and acid citrate dextrose solution B (Citrate) blood tubes compared to preservative-containing blood tubes. Blood samples spiked with prostate cancer cells were processed after 0, 24, 30, and 48 h storage at room temperature. The tumour cell isolation efficiency and the mRNA levels of the prostate cancer biomarkers androgen receptor variant 7 (AR-V7) and total AR, as well as epithelial cell adhesion molecule (EpCAM) were measured. Spiked cells were recovered across all storage tube types and times. Surprisingly, tumour mRNA biomarkers were readily detectable after 48 h storage in EDTA and Citrate tubes, but not in preservative-containing tubes. Notably, AR-V7 expression was detected in prostate cancer patient blood samples after 48 h storage in EDTA tubes at room temperature. This important finding presents opportunities for measuring AR-V7 expression from clinical trial patient samples processed within 48 h-a much more feasible timeframe compared to previous recommendations.
- Published
- 2017
- Full Text
- View/download PDF
22. Droplet Digital PCR Based Androgen Receptor Variant 7 (AR-V7) Detection from Prostate Cancer Patient Blood Biopsies.
- Author
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Ma Y, Luk A, Young FP, Lynch D, Chua W, Balakrishnar B, de Souza P, and Becker TM
- Subjects
- Cell Line, Tumor, Epithelial Cell Adhesion Molecule analysis, Humans, Male, Prostatic Neoplasms, Castration-Resistant pathology, RNA, Messenger analysis, Receptors, Androgen genetics, Sensitivity and Specificity, Biomarkers, Tumor blood, Microfluidics methods, Neoplastic Cells, Circulating pathology, Polymerase Chain Reaction methods, Prostatic Neoplasms, Castration-Resistant blood, Prostatic Neoplasms, Castration-Resistant diagnosis, Receptors, Androgen blood
- Abstract
Androgen receptor splice variant V7 (AR-V7) was recently identified as a valuable predictive biomarker in metastatic castrate-resistant prostate cancer. Here, we report a new, sensitive and accurate screen for AR-V7 mRNA expression directly from circulating tumor cells (CTCs): We combined EpCAM-based immunomagnetic CTC isolation using the IsoFlux microfluidic platform with droplet digital polymerase chain reaction (ddPCR) to analyze total AR and AR-V7 expression from prostate cancer patients CTCs. We demonstrate that AR-V7 is reliably detectable in enriched CTC samples with as little as five CTCs, even considering tumor heterogeneity, and confirm detection of AR-V7 in CTC samples from advanced prostate cancer (PCa) patients with AR-V7 detection limited to castrate resistant disease status in our sample set. Sensitive molecular analyses of circulating tumor cells (CTCs) or circulating tumor nucleic acids present exciting strategies to detect biomarkers, such as AR-V7 from non-invasive blood samples, so-called blood biopsies.
- Published
- 2016
- Full Text
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23. Patterns and trends in the incidence of paediatric and adult germ cell tumours in Australia, 1982-2011.
- Author
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van Leeuwen MT, Gurney H, Turner JJ, Turner SL, Pearson SA, Laaksonen MA, Harnett P, Balakrishnar B, Sabanathan D, and Vajdic CM
- Subjects
- Adolescent, Adult, Australia, Child, Child, Preschool, Female, History, 20th Century, History, 21st Century, Humans, Incidence, Infant, Male, Neoplasms, Germ Cell and Embryonal etiology, Young Adult, Neoplasms, Germ Cell and Embryonal epidemiology
- Abstract
Purpose: Germ cell tumour (GCT) aetiology is uncertain and comprehensive epidemiological studies of GCT incidence are few., Methods: Nationwide data on all malignant GCTs notified to Australian population-based cancer registries during 1982-2011 were obtained. Age- and sex-specific, and World age-standardised incidence rates were calculated for paediatric (0-14) and adult (15+) cases using the latest WHO subtype classification scheme. Temporal trends were examined using Joinpoint regression., Results: There were 17,279 GCTs (552 paediatric, 16,727 adult). Age-specific incidence in males (all histologies combined) was bimodal, with peaks during infancy for most sites, and second, larger, peaks during young adulthood. Incidence of ovarian tumours peaked at age 15-19. Around half of paediatric tumours were extragonadal, whereas adult tumours were mostly gonadal. Yolk sac tumours and teratomas predominated in infants, whereas germinomas became more frequent towards adulthood. Increasing incidence trends for some adult gonadal tumours have stabilised; the trend for male extragonadal tumours is also declining., Conclusion: Broad similarities in the shape of age-specific incidence curves, particularly for gonadal, central nervous system, and mediastinal tumours provide epidemiological support for commonalities in aetiology among clinically disparate GCT subtypes. Differences in peak ages reflect underlying subtype-specific biological differences. Declining incidence trends for some adult gonadal tumours accords with the global transition in GCT incidence, and supports the possibility of a reduction in prevalence of shared aetiological exposures., (Copyright © 2016 Elsevier Ltd. All rights reserved.)
- Published
- 2016
- Full Text
- View/download PDF
24. Dose Escalation of Tamoxifen in Patients with Low Endoxifen Level: Evidence for Therapeutic Drug Monitoring-The TADE Study.
- Author
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Fox P, Balleine RL, Lee C, Gao B, Balakrishnar B, Menzies AM, Yeap SH, Ali SS, Gebski V, Provan P, Coulter S, Liddle C, Hui R, Kefford R, Lynch J, Wong M, Wilcken N, and Gurney H
- Subjects
- Antineoplastic Agents, Hormonal administration & dosage, Breast Neoplasms pathology, Cytochrome P-450 CYP2D6 genetics, Female, Humans, Male, Middle Aged, Neoplasm Recurrence, Local drug therapy, Neoplasm Recurrence, Local pathology, Tamoxifen administration & dosage, Tamoxifen blood, Antineoplastic Agents, Hormonal therapeutic use, Breast Neoplasms drug therapy, Cytochrome P-450 CYP2D6 metabolism, Drug Monitoring methods, Tamoxifen analogs & derivatives, Tamoxifen therapeutic use
- Abstract
Purpose: Endoxifen is the major mediator of tamoxifen effect and endoxifen levels <15 nmol/L may be associated with increased risk of breast cancer recurrence. We increased tamoxifen dose in breast cancer patients with low endoxifen levels and assessed the influence of various parameters on reaching 15 nmol/L and 30 nmol/L endoxifen levels., Experimental Design: Tamoxifen dose was increased in those with endoxifen levels below 30 nmol/L. Toxicity, including hot flash score, was measured. CYP2D6 metabolizer status was classified as ultra-rapid (UM), extensive (EM), intermediate (IM), or poor (PM) based genotype of somatic DNA., Results: Dosage was escalated in 68 of 122 participants. On 20 mg tamoxifen, 24% had endoxifen levels below 15 nmol/L and this reduced to 6% following dose escalation. In over 50% of cases, there was no identified cause for low endoxifen. Low baseline endoxifen level, and not CYP2D6 metabolizer status, independently predicted reaching threshold targets for both the 15 nmol/L and 30 nmol/L targets (P = 0.04 and 0.003 respectively). The 15 nmol/L target was reached in all UM/EM and IM patients, 63% of PM patients, and 58% of those with baseline endoxifen of <10 nmol/L. There was no correlation between hot flash score and genotype or any tamoxifen metabolite level including endoxifen (R = 0.07)., Conclusions: Low endoxifen on standard dose tamoxifen was the only independent predictor of failure to achieve potentially therapeutic levels. Trials examining tamoxifen dose escalation and breast cancer outcome should be guided by endoxifen levels alone, without reference to CYP2D6 genotype or presence of hot flashes. Clin Cancer Res; 22(13); 3164-71. ©2016 AACRSee related commentary by Hertz and Rae, p. 3121., (©2016 American Association for Cancer Research.)
- Published
- 2016
- Full Text
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25. Predictive value of CYP3A and ABCB1 phenotyping probes for the pharmacokinetics of sunitinib: the ClearSun study.
- Author
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Kloth JS, Klümpen HJ, Yu H, Eechoute K, Samer CF, Kam BL, Huitema AD, Daali Y, Zwinderman AH, Balakrishnar B, Bennink RJ, Wong M, Schellens JH, Mathijssen RH, and Gurney H
- Subjects
- ATP Binding Cassette Transporter, Subfamily B chemistry, ATP Binding Cassette Transporter, Subfamily B genetics, Adult, Aged, Aged, 80 and over, Angiogenesis Inhibitors adverse effects, Antineoplastic Agents adverse effects, Biotransformation, Cytochrome P-450 CYP3A genetics, Female, Humans, Hypnotics and Sedatives pharmacokinetics, Indoles adverse effects, Male, Midazolam pharmacokinetics, Middle Aged, Phenotype, Prospective Studies, Pyrroles adverse effects, Radiopharmaceuticals pharmacokinetics, Sunitinib, Technetium Tc 99m Sestamibi pharmacokinetics, Angiogenesis Inhibitors pharmacokinetics, Antineoplastic Agents pharmacokinetics, Cytochrome P-450 CYP3A chemistry, Indoles pharmacokinetics, Pyrroles pharmacokinetics
- Abstract
Background and Objective: The wide inter-patient variability in drug exposure partly explains the toxicity and efficacy profile of sunitinib treatment. In this prospective study cytochrome P450 (CYP) 3A and adenosine triphosphate binding cassette (ABC) B1 phenotypes were correlated to the pharmacokinetics of sunitinib and its active metabolite N-desethylsunitinib., Methods: A correlation analysis was performed between sunitinib pharmacokinetics and 1'OH-midazolam/midazolam ratio and parameters derived from technetium-99m-2-methoxy isobutyl isonitrile ((99m)Tc-MIBI) scans, respectively. A population pharmacokinetic model using non-linear mixed-effects modeling software NONMEM was built, which included the phenotype tests as covariate., Results: In 52 patients, the mean trough concentration of sunitinib plus metabolite increased from 21.4 ng/mL at day 1 of a cycle to 88.1 ng/mL in the fourth week of treatment. A trend for a correlation was observed between (99m)Tc-MIBI elimination constant and trough concentrations of N-desethylsunitinib; however, this was not significant. Correlations were found between 1'OH-midazolam/midazolam ratio and sunitinib clearance (P = 0.008) and day 1 N-desethylsunitinib trough concentrations (P = 0.005), respectively. Moreover, patients suffering from grade 3 toxicities had significant lower clearance of sunitinib than patients without grade 3 toxicities (34.4 vs. 41.4 L/h; P = 0.025)., Conclusions: Phenotype tests for ABCB1 and CYP3A4 did not explain inter-individual variability of sunitinib exposure sufficiently. However, the correlation between sunitinib clearance and the occurrence of severe toxicity suggests a direct exposure-toxicity relationship.
- Published
- 2014
- Full Text
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26. Evidence for therapeutic drug monitoring of targeted anticancer therapies.
- Author
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Gao B, Yeap S, Clements A, Balakrishnar B, Wong M, and Gurney H
- Subjects
- Animals, Antibodies, Monoclonal administration & dosage, Antibodies, Monoclonal blood, Antibodies, Monoclonal, Humanized, Antibodies, Monoclonal, Murine-Derived administration & dosage, Antibodies, Monoclonal, Murine-Derived blood, Antineoplastic Agents adverse effects, Antineoplastic Agents pharmacokinetics, Area Under Curve, Benzamides, Benzenesulfonates administration & dosage, Benzenesulfonates blood, Cetuximab, Dasatinib, Everolimus, Evidence-Based Medicine, Half-Life, Humans, Imatinib Mesylate, Indoles administration & dosage, Indoles blood, Injections, Intravenous, Neoplasms metabolism, Niacinamide analogs & derivatives, Phenylurea Compounds, Piperazines administration & dosage, Piperazines blood, Pyridines administration & dosage, Pyridines blood, Pyrimidines administration & dosage, Pyrimidines blood, Pyrroles administration & dosage, Pyrroles blood, Rituximab, Sirolimus administration & dosage, Sirolimus analogs & derivatives, Sirolimus blood, Sorafenib, Sunitinib, Thiazoles administration & dosage, Thiazoles blood, Antineoplastic Agents administration & dosage, Antineoplastic Agents blood, Drug Monitoring methods, Molecular Targeted Therapy methods, Neoplasms blood, Neoplasms drug therapy
- Abstract
Therapeutic drug monitoring (TDM) provides valuable guidance for dose adjustment of antibiotics, immunosuppressives, antiepileptics, and other drugs, but its use for traditional anticancer therapies has been limited. Perhaps the most important obstacle is the impractical requirement of multiple blood samples to adequately define systemic exposure of drugs that have a short elimination half-life and are given by intermittent intravenous injections. However, the newer targeted anticancer therapies have different pharmacokinetic (PK) and dosing characteristics compared with traditional cytotoxic drugs, making it possible to estimate the steady-state drug exposure with a single trough-level measurement. Recent evidence indicates that certain PK parameters, including trough levels, are correlated with clinical outcomes for many of these agents, including imatinib, sunitinib, rituximab, and cetuximab. Although the current evidence is insufficient to mandate TDM in routine practice, a concerted investigation should be encouraged to determine whether the steady-state trough measurements of targeted agents will have a practical place in the clinical care of patients with cancer.
- Published
- 2012
- Full Text
- View/download PDF
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