This proof of concept study proposes targeted delivery of a broad-spectrum cytotoxic agent (doxorubicin), via a specially formulated LTSL (ThermoDox®) activated by mild hyperthermia, by using focused ultrasound (FUS), to achieve enhanced intra-tumoural doxorubicin concentrations for the same systemic dose. Adult patients with incurable confirmed hepatic primary or secondary tumours received a single cycle of LTLD, followed by ultrasound-mediated hyperthermia to a single target liver tumour. The primary endpoint relates to evidencing enhanced delivery of doxorubicin from LTLD at the target tumour site, by comparing intratumoural concentrations of the drug before and after focused ultrasound (FUS) exposure.
To date, purely pharmacological approaches have failed to address what is essentially a threefold challenge: (i) to deliver therapeutically significant concentrations of active agents to the tumour vasculature while minimizing off target effects; (ii) to release the therapeutic agent 'on-demand' at the target site; and, (iii) to improve the distribution and spread of the therapeutic agent against the intra-tumoural pressure gradient in order to achieve a therapeutically relevant concentration throughout the tumour. Recent pre-clinical studies performed at Oxford using ThermoDox® released using FUS has shown that increased uptake at the target site is achievable. Hence there is great promise in using this combination therapy to achieve increased tumour uptake and local dose for the equivalent dose of doxorubicin used in systemic chemotherapy for human subjects, which has a well established and safe toxicity profile. The first extracorporeal FUS device in Europe was used for a study performed at Oxford between 2002 and 2004. This single centre trial was sponsored by the University of Oxford. The recruiting study site was Oxford University Hospitals NHS Trust, where there is extensive clinical FUS experience. The study is split into two parts. Part I identified optimal FUS exposure parameters for a range of patient BMIs and tumour locations within the liver using real time thermometry data from an implanted thermistor. After at least 5 and no more than 14 participants have had the intervention using real-time thermometry, data was reviewed by the Trial Management Group (TMG) to confirm readiness to proceed without real-time thermometry. Part II, which did not require thermistor implantation, is designed to reflect how the therapy would be implemented in clinical practice. Participants received treatment for 1 day and are followed up for 30 days. All evaluable participants from both Part I and Part II were included in the endpoint analysis. Doxorubicin concentrations were directly determined from tissue biopsies of the target tumour, using a Good Laboratory Practice-validated high performance liquid chromatography (HPLC) assay, based on previously published methods. If this study demonstrates successful targeted drug delivery in human subjects using LTSLs released by mild-hyperthermia, this could potentially transform the future of chemotherapy in clinical practice; targeted therapy using LTSLs containing other chemotherapeutic agents triggered non-invasively by mild hyperthermia could be applied to any solid organ cancer.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
10
ThermoDox® (LTLD) infusion at a dose of 50mg/m2 whilst under general anaesthetic during intervention (Day 1)
Whilst the ThermoDox® was circulating in the blood stream, the JC200 Therapeutic Ultrasound device was used to induce mild hyperthermia in a single (region of) a target liver tumour.
A clinically approved thermistor or thermocouple was placed in the target liver tumour for real-time thermometry.
Oxford University Hospitals NHS Trust
Oxford, United Kingdom
Concentration of Total Intratumoral Doxorubicin in Liver Tumour (Biopsies) Following Targeted Release of Doxorubicin From ThermoDox® ('Drug') Using Mild Hyperthermia Generated Non-invasively by Focused Ultrasound (FUS)
Analytical chemistry (High Performance Liquid Chromatography) for total doxorubicin (including both released and unreleased forms) was performed on section of intratumoral biopsy samples in Good Clinical Practice Laboratory, using a validated assay. Doxorubicin concentration was evaluated in biopsy samples both post-LTLD and post-LTLD+FUS. Tumour samples were not analysed same day and were frozen at -80\^oC for subsequent analysis. Required to evaluate the primary endpoint.
Time frame: Post-intervention sample (Day 1) compared to pre-intervention sample (Day 1)
Patients Demonstrating >Two-fold Increase in the Amount of Intratumoural Doxorubicin Before and After Focused Ultrasound
To satisfy the primary endpoint, a demonstrable two-fold increase in\*, or value exceeding 10μg/g of, the concentration of intra-tumoural doxorubicin at the treated tumour site following FUS-induced mild hyperthermia, was required in at least 50% of evaluable participants. \* As per the a priori protocol design, in Part II the biopsy prior to FUS-induced mild hyperthermia is not performed and therefore the average value for all evaluable tumours receiving intervention in Part I is used as a comparison for the two-fold increase from pre-FUS to post-FUS biopsy.
Time frame: Post-LTLD+FUS sample (Day 1) compared to Post-LTLD sample (Day 1)
(Part I Only) Achievement of Satisfactory Hyperthermia Within the Target Liver Tumour for a Range of Participant Body Mass Indices (BMIs) and Tumour Locations Within the Liver (Optimal FUS Exposure Parameters)
Achievement of hyperthermia in the target liver tumour, as determined by real-time thermometry obtained by an indwelling thermometry device. For success, sustained and controlled hyperthermia is required in the target tumour, consequent with drug release (in excess of 39.5\^oC). Real time thermometry plots for each Part I patient are available in the key Lancet Oncology publication, details available in the References section.
Time frame: Real-time thermometry monitoring during intervention (Day 1)
Persistence of Cell Viability Stain Post-LTLD+FUS
Post-LTLD+FUS tissue from the targeted liver tumours was obtained by biopsy at the time of the intervention, between 24/03/2015 and 29/03/2017. Cytokeratin-8 (CK-8) is a cell viability marker which if present, demonstrates lack of ablative cell death by any ablative modality, including FUS. Not all histological cell types express CK8, thus if the Post-LTLD+FUS it may either indicate: i) Non-CK8 expression ii) Thermal ablation and consequent cell death. Note there was uncertainty about CK8 expression of individual patient tumours prior to recruitment. In this study if the Post-LTLD+FUS tissue shows specific cellular CK8 cellular staining, then it demonstrates that i) the tumour is CK8+, and, ii) the tumour was not instantaneously thermally ablated and any subsequent cell death is likely due to drug delivery/chemo-ablation. For more information see key TARDOX Lancet Oncology publication and Cytokeratin 8 reference (both detailed in References section).
Time frame: Tissue obtained on day of intervention (Day 1). All CK8 cell viability staining was performed within 2 months of sampling.
Patients With Significant (Grade 3-5) Adverse Event(s) Deemed Related to ThermoDox (LTLD)
Adverse Events are listed separately in the subsequent results, but were also specified as a secondary endpoint in the a priori protocol and thus significant events are summarised here. 'Definitely' or 'Probably' related events are included.
Time frame: Up to 30 days post-intervention (Day 1-30)
Patients With Significant (Grade 3-5) Adverse Event(s) Deemed Related to FUS Procedure
Adverse Events are listed separately in the subsequent results, but were also specified as a secondary endpoint in the a priori protocol and thus significant events are summarised here. 'Definitely' or 'Probably' related events are included.
Time frame: Up to 30 days post-intervention (Day 1-30)
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