Microvascular angina (MVA) is caused by abnormalities of the small vessels in the heart. Endothelin is a small chemical that circulates and accumulates in the blood vessel walls, causing them to narrow or go into spasm and thicken in the longer term especially as levels of endothelin increase. As a result, patients experience pain, psychological burden and an inability to carry out daily activities. Originally developed by AstraZeneca for cancer treatment, prior research has confirmed that Zibotentan relaxes the small blood vessels of patients with MVA which lends support to the idea that Zibotentan may bring some benefits to patients with MVA. This trial therefore proposes to look into re-purposing zibotentan as a new treatment for patients with MVA. The primary objective is to assess the effect of add-on treatment with Zibotentan to treadmill exercise times in adult patients with MVA and impaired exercise intolerance. Zibotentan could provide a new treatment pathway for patients, as well as be made available to the NHS at substantially lower cost than the currently used medications. The trial aims to initially invite approx. 356 participants for genetic testing. A minimum of 100 participants will go forward into the main study, receiving either 10mg zibotentan or a dummy matched tablet (placebo) daily over two 12 weeks periods of each, completing their final visit at week 34. The study assessments will involve a health check at each visit, including information on the patient's wellbeing, blood tests, some quality of life questionnaires, and an exercise test. Participants will also have the option to consent to additional sub-study cardiovascular MRI scanning. Finally, participants will be invited to provide consent for long-term follow-up (maximum 20 years) of their electronic medical records (no additional patient contact).
The study design publication is available at https://pubmed.ncbi.nlm.nih.gov/32942043/
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
225
10mg OD Zibotentan
Placebo
NHS Greater Glasgow and Clyde
Glasgow, United Kingdom
EFFICACY - Exercise Testing (treadmill exercise time, seconds)
The primary outcome is the treadmill exercise time (TET) measured in seconds using the Full Bruce protocol, a measure of aerobic capacity that reflects disease severity. A within-subject improvement in exercise time (tested at week 10 (baseline), week 22 (crossover) and week 34 (final visit)) of 30 seconds is considered clinically relevant.
Time frame: 34 weeks
EFFICACY - Health Status QLQ (Seattle Angina Questionnaire)
Seattle Angina Questionnaire (SAQ) Summary Score and component scores (Angina Limitation, Angina Stability, Angina Frequency, Treatment Satisfaction and Quality of Life) will be recorded at all study visits.
Time frame: 34 weeks
EFFICACY - Health Status QLQ (Illness Perception - Brief IPQ)
Brief Illness Perception Questionnaire (Brief IPQ), a nine-item scale designed to rapidly assess the cognitive and emotional representations of illness taken at all study visits.
Time frame: 34 weeks
EFFICACY - Health Status QLQ (Anxiety/depression - PHQ4)
The Four-Item Patient Health Questionnaire (PHQ-4) for Anxiety and Depression is a validated tool for detecting both anxiety and depressive disorders and will administered at all study visits
Time frame: 34 weeks
EFFICACY - Health Status QLQ (Treatment satisfaction - TSQM)
The 14-item Treatment Satisfaction Questionnaire for Medication (TSQM) is a reliable and valid instrument to assess patients' satisfaction with medication, providing scores on four scales - side effects, effectiveness, convenience and global satisfaction and will administered at all study visits
Time frame: 34 weeks
EFFICACY - Health Status QLQ (EQ5D-5L)
The 5-item EuroQol Group EQ5D-5L is a validated questionnaire comprising mobility, self-care, usual activities, pain/discomfort and anxiety/depression to quantitatively assess patient's self-reported health status and will be administered at each study visit.
Time frame: 34 weeks
FEASIBILITY - Withdrawal Rate
Participant withdrawal rate from study will be measured throughout.
Time frame: 34 weeks
SAFETY - SAEs
Number of Participants With Treatment-Related Adverse Events as Assessed and reported by local study teams throughout trial.
Time frame: 34 weeks
EFFICACY - Exercise Testing (time,sec to 1mm ST-depression)
Within-subject improvements in time (seconds) to 1 mm ST-depression during exercise tolerance testing will be assessed using the Full Bruce protocol. Assessments will be during screening, week 10 (baseline), week 22 (crossover) and week 34 (final visit).
Time frame: 34 weeks
EFFICACY - Exercise Testing (maximum ST-segment deviation, mV)
Within-subject improvements in maximum ST-segment deviation (mV) during exercise tolerance testing will be assessed using the Full Bruce protocol. Assessments will be during screening, week 10 (baseline), week 22 (crossover) and week 34 (final visit).
Time frame: 34 weeks
EFFICACY - Exercise Testing (Time (s) to 75% of max age-related heart rate during exercise)
Within-subject improvements in time (seconds) to 75% of max age-related heart rate during exercise tolerance testing will be assessed using the Full Bruce protocol. Assessments will be during screening, week 10 (baseline), week 22 (crossover) and week 34 (final visit).
Time frame: 34 weeks
EFFICACY - Exercise Testing (Metabolic equivalent (METs)
Within-subject improvements in metabolic equivalent (METs) during exercise tolerance testing will be assessed using the Full Bruce protocol. Assessments will be during screening, week 10 (baseline), week 22 (crossover) and week 34 (final visit). The resting metabolic rate is defined as 3.5 ml O2/kg/min (METs).
Time frame: 34 weeks
EFFICACY - Exercise Testing (DUKE Score)
Within-subject improvements in Duke treadmill score (DTS) during exercise tolerance testing will be assessed using the Full Bruce protocol. Assessments will be during screening, week 10 (baseline), week 22 (crossover) and week 34 (final visit). Duke treadmill score is defined as maximum exercise time in minutes - (5 × the maximal net ST-segment deviation in mm during or after exercise) - (4 × the treadmill angina index (where 0 = no angina, 1 = non-limiting angina, 2 = exercise limiting angina).
Time frame: 34 weeks
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