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Trial registered on ANZCTR


Registration number
ACTRN12617001109392
Ethics application status
Approved
Date submitted
25/07/2017
Date registered
28/07/2017
Date last updated
5/02/2020
Date data sharing statement initially provided
4/02/2019
Type of registration
Prospectively registered

Titles & IDs
Public title
An observational study to assess the ability of the thymine loading test to prospectively categorise patients with gastrointestinal or breast cancer who cannot tolerate fluoropyrimidine treatment.
Scientific title
An observational study to assess the ability of the thymine loading test to prospectively categorise patients with gastrointestinal or breast cancer who cannot tolerate fluoropyrimidine treatment.
Secondary ID [1] 292512 0
CTNZ-2016-04
Universal Trial Number (UTN)
U1111-1199-7456
Trial acronym
THYmine 2
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Gastrointestinal (GI) cancer 304149 0
Breast cancer 304150 0
Condition category
Condition code
Cancer 303480 303480 0 0
Bowel - Anal
Cancer 303481 303481 0 0
Bowel - Back passage (rectum) or large bowel (colon)
Cancer 303482 303482 0 0
Bowel - Small bowel (duodenum and ileum)
Cancer 303483 303483 0 0
Breast
Cancer 303484 303484 0 0
Stomach

Intervention/exposure
Study type
Observational
Patient registry
False
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
This study is an observational study. Thymine test results will not affect any treatment decisions.

At a scheduled assessment clinic visit, >24 hours prior to the commencement of treatment with 5-FU/capecitabine containing schedules:
A baseline blood sample will be obtained (one 10 ml sample) as well as a baseline spot urine sample. A cheek (buccal) cell sample will also be obtained. This will involve using a cytobrush to take a brushing of the inside of the cheek (like using a toothbrush on the inside of the mouth). This will be done twice (one on each side of the mouth) and will require a mouth wash with water prior to the first brushing. The participants will then be administered thymine (250 mg, oral gelatine capsule) with a drink of water. A cumulative (total) urine sample will be collected for the next 4 hours.

All patients who have been given the thymine test will then continue on their planned chemotherapy treatment. All patients will be assessed for adverse events related to 5-FU/capecitabine treatment. Information will be collected at each scheduled clinic visit for 8 – 9 weeks while on normal chemotherapy treatment.

Analysis will involve urine sample for thymine and its metabolite (dihydrothymine or DHT). Cheek cells will be used to assess 5-FU uptake in vitro and genomic DNA (from blood) will be used to analysing variation in the DPYD gene and further analysis of genes associated with 5-FU side effects.
Intervention code [1] 298696 0
Not applicable
Comparator / control treatment
No control group
Control group
Uncontrolled

Outcomes
Primary outcome [1] 302853 0
The primary outcome is the presence of severe DM toxicity. All diarrhoea (D) and mucositis (M) toxicities will be identified and coded according to CTCAE criteria. Patients with grade 2 or less GI events or haematotoxicity, or grade 1 or less hand-foot syndrome will be coded as minimal toxicity. For patients with a Grade 3 or higher D or M toxicity a review will be carried out by a clinical PI (blinded to thymine test results and genomic information).
Timepoint [1] 302853 0
Information will be collected at each scheduled clinic visit for 8 – 9 weeks while on normal chemotherapy treatment.
Secondary outcome [1] 337250 0
Comparison of the thymine test to the predictive ability of a panel of known deleterious SNP in the DPYD gene: Genomic DNA will be prepared from the blood sample using a PAXgene blood DNA kit.

The frequency of each SNP will be determined and compared to the published frequencies for Caucasian individuals in dbSNP (https://www.ncbi.nlm.nih.gov/SNP/).
Each SNP will be assessed for any departure from Hardy-Weinberg equilibrium. Each patient will be classified according to whether or not any of the deleterious variants of DPYD were detected in their sample. Agreement between the gene test and the thymine test results (THY/DHT ratio) will described using separate 2x2 tables for the toxicity groups.
Timepoint [1] 337250 0
A single blood sample will be collected from each patient at baseline prior to thymine administration.
Secondary outcome [2] 337251 0
Transmembrane uptake of 5-FU into cells from buccal mucosa: Buccal (cheek) cells will be used to assess 5-FU uptake in vitro using radiolabelled drug.

The amount of transmembrane uptake of 5-FU into buccal mucosal cells from each individual will be reported as pmol.min.10-4 live cells. The range of inter-individual differences in 5-FU transmembrane uptake will be addressed by i) presenting the distribution, and the median and IQ range of the uptake values and ii) by comparing the values in the severe and very severe toxicity group to the minimal toxicity group.
Timepoint [2] 337251 0
Buccal (cheek) cell sample will be collected once on the day of the thymine test prior to thymine administration (i.e. baseline). The uptake of 5-FU into these cells will then be immediately assessed on the same day as the collection.
Secondary outcome [3] 379591 0
The total dosage of capecitabine or 5-FU received in the first cycle. Dosage will be reported as per Body Surface Area (g/m2). The range of dosage will be reported for 5-FU vs capecitabine groups. The prevalence of severe-very severe toxicity in 5-FU vs capecitabine groups will be reported.
Timepoint [3] 379591 0
Information will be collected at the scheduled clinic visit after first cycle of chemotherapy treatment.
Secondary outcome [4] 379592 0
This secondary outcome includes Neutropenia in the definition of 5-FU toxicity (DNM toxicity). Hence the outcome is the presence of severe of DMN toxicity. All diarrhoea (D), mucositis (M) and neutropenia (N) toxicities will be identified and coded according to CTCAE criteria. Patients with grade 2 or less GI events or haematotoxicity, or grade 1 or less hand-foot syndrome will be coded as minimal toxicity. For patients with a Grade 3 or higher D, M or N toxicity a review will be carried out by a clinical PI (blinded to thymine test results and genomic information).
Timepoint [4] 379592 0
Information will be collected at each scheduled clinic visit for 8 – 9 weeks while on normal chemotherapy treatment.
Secondary outcome [5] 379593 0
Presence of grade 2 or 3 hand-foot syndrome coded according to CTCAE criteria. Hand-foot syndrome could be caused by aberrant disposition of 5-FU/capecitabine. Grade 2 or higher hand-foot syndrome is considered clinically significant.
Timepoint [5] 379593 0
Information will be collected at each scheduled clinic visit for 8 – 9 weeks while on normal chemotherapy treatment.

Eligibility
Key inclusion criteria
- Age >18 years.
- To receive 5-FU or capecitabine (GI) or capecitabine (mBC) as part of standard care for histologically or cytologically confirmed gastrointestinal (GI) cancer or metastatic breast cancer (mBC); OR
- To receive capecitabine as part of standard care for residual disease present at surgery following neoadjuvant chemotherapy for breast cancer
- Able to provide written informed consent
Minimum age
18 Years
Maximum age
No limit
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
- Pregnant or breast feeding
- Concurrent abdomino-pelvic radiation therapy
- Irinotecan containing schedules
- Prior history of infusional 5-FU or capecitabine

Study design
Purpose
Natural history
Duration
Longitudinal
Selection
Defined population
Timing
Prospective
Statistical methods / analysis
Based on literature and meta-analyses, it is expected that around 25% or 50 of the 200 patients will have Grade 3 diarrhoea, mucositis or neutropenia (DMN) toxicity (and hence severe or very severe DMN toxicity) and around 8% will have very severe DMN toxicity. Very limited data are available on the variability THY/DHT ratio, however a large effect size (difference in means divided by sd) is essential to give sufficient separation for the test to be clinically useful. To give an indication, with group sizes of 50 and 150, the study would have 80% power to detect effect sizes of 0.5 if the variances in groups 1 and 2 were equal. Since a minimum clinically important effect size would be substantially larger than 0.5 in this setting, the sample size should be sufficient to allow for decreases in power due to unequal variances. For analyses of very severe toxicity compared to minimal toxicity the power will be lower as we anticipate only 16 patients in this group (8%). With 16 patients (vs 150 with minimal toxicity) the study would have 80% power to detect effect sizes of around 0.9. We note that prospective pharmacogenomic testing for a single DPYD variant was determined to have clinical utility in a similar sample size, despite gene testing having low sensitivity. Sample size calculations were carried out in Stata.

Primary analysis:
The urinary THY/DHT ratio in the severe and very severe DM toxicity groups combined will be compared to that of the group with minimal toxicity using a Wilcoxon rank sum test. Minimal toxicity is those with grade 2 or less GI events or haematotoxicity, or grade 1 or less hand-foot syndrome. The non-parametric test was chosen because the distribution for the THY/DHT ratio is hypothesized to have much greater variability with positive skew in those with severe toxicity compared to those with minimal toxicity. The test will be one sided (an alternative hypothesis that the ratio is higher in those with more severe toxicity) with a significance level of 0.025.

The difference in mean THY/DHT ratio for the severe and very severe DM toxicity vs the minimal toxicity groups and a 95% confidence interval will be calculated. A cut-off for a diagnostic test based on the THY/DHT ratio will be determined as the value which gives a specificity of 85% in the minimal toxicity group. The sensitivity of the test will be calculated as the proportion of the very severe or severe DM toxicity group with THY/DHT ratio values above the cut-off. An exact 95% confidence interval will be presented. The above analyses will be repeated for the group with very severe toxicity compared to those with minimal toxicity.

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment outside Australia
Country [1] 9083 0
New Zealand
State/province [1] 9083 0

Funding & Sponsors
Funding source category [1] 297083 0
Government body
Name [1] 297083 0
Health Research Council of New Zealand (HRC)
Address [1] 297083 0
PO Box 5541, Wellesley Street, Auckland 1141.
Country [1] 297083 0
New Zealand
Funding source category [2] 301849 0
Charities/Societies/Foundations
Name [2] 301849 0
Gut Cancer Foundation
Address [2] 301849 0
29 Jubilee Ave,
Onehunga,
Auckland 1061
New Zealand
Country [2] 301849 0
New Zealand
Primary sponsor type
University
Name
University of Auckland
Address
Private Bag 92019. Auckland 1142.
Country
New Zealand
Secondary sponsor category [1] 296087 0
None
Name [1] 296087 0
Address [1] 296087 0
Country [1] 296087 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 298262 0
Central Health and Disability Ethics Committees
Ethics committee address [1] 298262 0
Ministry of Health
Health and Disability Ethics Committees
PO Box 5013
Wellington 6140
Ethics committee country [1] 298262 0
New Zealand
Date submitted for ethics approval [1] 298262 0
03/08/2017
Approval date [1] 298262 0
05/10/2017
Ethics approval number [1] 298262 0
17/CEN/149

Summary
Brief summary
The primary aim of this study is to determine whether the ratio of thymine to dihydrothymine (THY/DHT) measured in a urine sample after a thymine test dose (250 mg, taken orally) can discriminate between patients who tolerate 5-FU treatment and those who experience severe 5-FU related toxicity.
Trial website
Not available
Trial related presentations / publications
N/a
Public notes

Contacts
Principal investigator
Name 76510 0
A/Prof Nuala Helsby
Address 76510 0
Faculty of Medical and Health Sciences
University of Auckland
Private Bag 92019
Auckland 1142
Country 76510 0
New Zealand
Phone 76510 0
+64 9 923 9831
Fax 76510 0
Email 76510 0
n.helsby@auckland.ac.nz
Contact person for public queries
Name 76511 0
A/Prof Nuala Helsby
Address 76511 0
Faculty of Medical and Health Sciences
University of Auckland
Private Bag 92019
Auckland 1142
Country 76511 0
New Zealand
Phone 76511 0
+64 9 923 9831
Fax 76511 0
Email 76511 0
n.helsby@auckland.ac.nz
Contact person for scientific queries
Name 76512 0
A/Prof Nuala Helsby
Address 76512 0
Faculty of Medical and Health Sciences
University of Auckland
Private Bag 92019
Auckland 1142
Country 76512 0
New Zealand
Phone 76512 0
+64 9 923 9831
Fax 76512 0
Email 76512 0
n.helsby@auckland.ac.nz

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
IPD will not be available for this study.
What supporting documents are/will be available?
No other documents available
Summary results
No Results