WILL lOWer Dose Aspirin be Better With Rivaroxaban in Patients With Chronic Coronary Syndromes? (WILLOW CCS)

Characterisation of a Novel Regimen of Very Low-dose Aspirin Combined With Rivaroxaban in Patients With Chronic Coronary Syndromes: WILL lOWer Dose Aspirin be Better With Rivaroxaban in Patients With Chronic Coronary Syndromes?

The trial is a pharmacodynamic study to determine the effect of a novel regimen of aspirin 20 mg BD plus rivaroxaban 2.5 mg BD on haemostasis, fibrin clot dynamics, inflammatory markers, platelet function and arachidonic acid metabolites when compared to standard regimens of aspirin 75 mg OD and aspirin 75 mg OD plus rivaroxaban 2.5 mg BD.

In a randomised open-label three-period crossover design, patient participants receiving aspirin 75 mg OD for secondary prevention of IHD will be randomised 1:1 to receive one of two sequences of aspirin: aspirin 75 mg OD, then aspirin 20 mg BD plus rivaroxaban 2.5 mg BD, then aspirin 75 mg OD plus rivaroxaban 2.5 mg BD; or aspirin 75 mg OD, then aspirin 75 mg OD plus rivaroxaban 2.5 mg BD, then aspirin 20 mg BD plus rivaroxaban 2.5 mg BD.

At the end of each 14(-2) day medication period, they will attend a study visit at which blood and urine samples will be obtained, and bleeding time measured, before and 2 hours after the last dose of IMP of the treatment period. The samples will be tested for fibrin clot dynamics; inflammatory markers and cytokines; prostanoids; and platelet function.

Participants will be transitioned back to standard-of-care aspirin 75 mg OD at the end of the third treatment period and followed up by telephone call 14(-2) days later.

Study Overview

Detailed Description

Recruitment Potential participants will be identified through review of the records of the South Yorkshire Cardiothoracic Centre and/or by referral by their clinical team.

Specifically, participants may be approached in the following ways:

  1. An invitation letter sent by post in combination with a copy of the participant information sheet. There will be a reply slip which they can return by post, and there will be contact details (telephone and email) for the research team to allow them to respond by these methods too.
  2. Directly by telephone. In this case, should they be happy to learn more, they will be sent a copy of the invitation letter, participant information sheet and reply slip by post or email, depending on their preference. If they agree to attend for study screening, they will communicate this to the research team by returning the reply slip by post or email, or by contacting the research team directly using the contact details provided to them.
  3. Directly in clinics within the Cardiology and Cardiothoracic Surgery Directorate at Sheffield Teaching Hospitals NHS Foundation Trust, upon referral from their clinical team. In this case they will be provided with a copy of the participant information sheet and, if unable to decide whether they wish to attend for screening or not during the clinic visit, will be signposted to the contact details of the research team to provide their response.

    Potential participants who are interested in taking part in the study will then be contacted by the research team to book a screening appointment.

    Screening

    Screening will occur at visit 1. The following study procedures will be performed, after obtaining written consent for the study:

    • Medical history
    • Physical examination
    • Collection of demographic data
    • Vital signs (pulse, blood pressure and temperature).
    • Height, weight and BMI
    • Recording of any concomitant medication
    • Safety blood tests (13.5 ml blood sample for haematology, clinical chemistry and coagulation)
    • Urinalysis (dipstick), plus urinary pregnancy test if female and of childbearing potential. This will also be checked immediately prior to first rivaroxaban exposure at visit 3.
    • Baseline electrocardiogram

    Consent Written, informed consent, using the current version of the approved designated form for this study, will be obtained prior to any study procedures being carried out. This will be explained and obtained by a medically-qualified member of the research team, listed on the delegation log. Participants will have the chance to read the ICF/PIS for as long as they need, and will be able to ask any questions, prior to signing. Minors and those judged to be without the mental capacity to provide informed consent will not be enrolled into the study.

    Participants will remain free to withdraw at any time from the trial, without giving reasons and without prejudicing his/her further treatment, and will be provided with a contact point where he/she may obtain further information about the trial. Samples collected up to the point of withdrawal will only be used after withdrawal if the participant consents for this, otherwise they will be destroyed. However, data collected up to that point will be used for analysis, and this will be explicitly stated in the participant information sheet and consent form.

    The randomisation scheme

    Participants will be randomised to one of the following two treatment sequences, in a 1:1 fashion:

    (A) Aspirin 75 mg OD for 14(-2) days then aspirin 20 mg BD plus rivaroxaban 2.5 mg BD for 14(-2) days then aspirin 75 mg OD plus rivaroxaban 2.5 mg BD or (B) Aspirin 75 mg OD for 14(-2) days then aspirin 75 mg OD plus rivaroxaban 2.5 mg BD for 14(-2) days then aspirin 20 mg BD plus rivaroxaban 2.5 mg BD

    Baseline data At visit 1

    • Medical history
    • Physical examination
    • Demographic data
    • Vital signs (pulse, blood pressure and temperature)
    • Weight and BMI
    • Concomitant medication
    • Lab safety parameters (full blood count, urea & electrolytes, liver function tests, clotting screen, dipstick urinalysis, urinary pregnancy test if female and of childbearing potential)
    • Electrocardiogram findings At visit 2
    • Vital signs: pulse, blood pressure and temperature
    • Physical examination

    Visit 1 - Screening (Day -21 to 0)

    Screening of subjects and all study-related procedures will take place in the Sheffield Clinical Research Facility, a specialist environment for the conduct of clinical research. The following assessments and procedures will be performed:

    - Full informed consent, including completion of the informed consent form

    • Inclusion/exclusion criteria (see section 6)
    • Medical history
    • Physical examination
    • Demographic data
    • Vital signs: pulse, blood pressure and temperature
    • Weight and BMI
    • Concomitant medication
    • Lab safety (13.5 ml blood sample for haematology; clinical chemistry & coagulation; urinalysis)
    • Electrocardiogram

    Visit 2 (Day 0) - Randomisation

    • Vital signs
    • Physical examination
    • Reconfirm eligibility criteria met (by a medically qualified member of the study team, see section 6) and no withdrawal criteria met (section 7.10)
    • Randomisation
    • Provided with supply of aspirin (aspirin lysine) for periods 1, 2 and 3 (2 boxes of 30 sachets)
    • Dose-preparation training for aspirin (aspirin lysine) 75 mg OD, including supply of written illustrated instructions
    • Issue with participant information card detailing treatment allocation, restrictions during the study and contact details for the research team

    Period 1: 14 (-2) days - Participants will receive aspirin (aspirin lysine) 75 mg OD, but should withhold their dose on the morning of visit 3 (during which the dose will be taken).

    Visit 3 - Period 1: Day 14 (-2)

    • Vital signs
    • Physical examination
    • Adverse event recording
    • Concomitant medication recorded
    • Venous blood sample pre- and 2 hours post-dose for fibrin clot dynamics, inflammatory markers, prostanoids and platelet function
    • Bleeding time pre- and 2 hours post dose
    • Urine sample pre- and 2 hours post-dose for prostanoids
    • IMP compliance check for period 1
    • Dispensing of rivaroxaban 2.5 mg tablets for periods 2 and 3 (total 56 tablets)
    • Urine pregnancy test for women of childbearing potential (must not continue to period 2 if positive)
    • Dose-preparation training for aspirin (aspirin lysine) 20 mg BD if allocated to sequence A, including provision of written instructions

    Period 2: 14(-2) days

    Participants will receive their allocated regimen for period 2 for 14(-2) days:

    • If randomised to sequence A they will receive aspirin (aspirin lysine) 20 mg BD plus rivaroxaban 2.5 mg BD in period 2.
    • If randomised to sequence B they will receive aspirin (aspirin lysine) 75 mg BD plus rivaroxaban 2.5 mg BD in period 2.

    Participants should withhold their dose on the morning of visit 4 (during which the dose will be taken).

    Visit 4 : 14(-2) days into period 2 - Physical examination

    • Adverse event recording
    • Concomitant medication recorded
    • Venous blood sample pre- and 2 hours post-dose for fibrin clot dynamics, inflammatory markers, prostanoids and platelet function
    • Bleeding time pre- and 2 hours post dose
    • Urine sample pre- and 2 hours post-dose for prostanoids
    • IMP compliance recorded for period 2
    • Dose-preparation training for aspirin (aspirin lysine) 75 mg OD if allocated to sequence A or 20 mg BD if sequence B, including provision of written instructions

    Period 3: 14(-2) days

    Participants will receive their allocated regimen for period 3 for 14(-2) days:

    • If randomised to sequence A they will receive aspirin (aspirin lysine) 75 mg OD plus rivaroxaban 2.5 mg BD in period 3.
    • If randomised to sequence B they will receive aspirin (aspirin lysine) 20 mg BD plus rivaroxaban 2.5 mg BD in period 3.

    Visit 5 : 14(-2) days into period 3 - Vital signs

    - Physical examination

    - Adverse event recording

    - Concomitant medication recorded

    - Venous blood sample pre- and 2 hours post-dose for fibrin clot dynamics, inflammatory markers, prostanoids and platelet function

    - Bleeding time pre- and 2 hours post dose

    - Urine sample pre- and 2 hours post-dose for prostanoids

    - IMP compliance recorded for period 3

    • Collect and return unused medication to pharmacy
    • Transition to standard of care aspirin 75 mg OD, ensuring participant has a supply of this

    Visit 6 : 14(-2) days after visit 5 (Telephone call) - Telephone follow-up for adverse events and concomitant medication

Study Type

Interventional

Enrollment (Actual)

48

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • South Yorkshire
      • Sheffield, South Yorkshire, United Kingdom, S5 7AU
        • Sheffield Teaching Hospitals NHS Foundation Trust

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Provision of informed consent prior to any study specific procedures
  2. Male or female aged greater than 18 years
  3. Existing diagnosis of a chronic coronary syndrome:

    (i) History of stable angina or (ii) History of an acute coronary syndrome event >1 year ago or (iii) Previous evidence on imaging of either at least one stenosis >50% in an epicardial coronary artery or a myocardial perfusion defect

  4. Receiving single antiplatelet therapy with aspirin 75 mg once daily

Exclusion Criteria:

  1. Any history of haemorrhagic stroke or lacunar stroke
  2. History of ischaemic stroke or transient ischaemic attack in the last year
  3. Heart failure associated with NYHA class III or IV symptoms
  4. Estimated glomerular filtration rate <15 ml/min
  5. Planned procedure for coronary revascularization
  6. Any planned surgery or other procedure that may require suspension or discontinuation of antiplatelet therapy expected to occur within 3 months of randomisation
  7. Prior intention by patient or physician to discontinue aspirin within the study period
  8. Receiving doses of aspirin other than 75 mg once daily
  9. Treatment or planned treatment with antiplatelet medication apart from aspirin (eg. clopidogrel, prasugrel, ticagrelor, dipyridamole, ticlopidine)
  10. Current use of a loop, thiazide or potassium sparing diuretic (affects prostanoid assays)
  11. Any acute coronary syndrome event, percutaneous coronary intervention or coronary artery bypass grafting within 1 year prior to randomisation
  12. Current or planned use of an oral anticoagulant (e.g. warfarin, dabigatran, rivaroxaban [including 2.5 mg BD], apixaban, edoxaban) or parenteral anticoagulant (eg. unfractionated heparin, low molecular weight heparin, bivalirudin)
  13. Current or planned use of a GPIIb/IIIa inhibitor (eg. abciximab, tirofiban)
  14. Current or planned use of a fibrinolytic agent (eg. tissue plasminogen activator)
  15. Requiring or likely to require treatment with a non-steroidal anti-inflammatory drug (NSAID), including COX2 inhibitors, and including regular or intermittent/as required use
  16. Current or planned use of a strong CYP3A4 inhibitor (eg, ketoconazole, itraconazole, voriconazole, telithromycin, clarithromycin [but not erythromycin or azithromycin], nefazadone, ritonavir, saquinavir, nelfinavir, indinavir, atanazavir, cobicistat or over 1 litre daily of grapefruit juice), strong inducer (e.g. rifampin/rifampicin, rifabutin, phenytoin, carbamazepine, phenobarbital), a selective serotonin reuptake inhibitor (SSRI) or selective noradrenergic reuptake inhibitor (SNRI).
  17. Clinically significant liver disease, defined as known or suspected diagnosis of hepatic cirrhosis with current Child Pugh class B or C; or elevation of serum alanine transferase or aspartate transferase greater than 3 times the upper limit of the normal range for the processing laboratory.
  18. History of alcohol or drug abuse, defined as regular use of an illicit substance for recreational purposes or regular consumption of greater than 50 units (males) or 35 units (females) of alcohol per week, in the last year
  19. Co-morbidity associated with life expectancy less than 1 year
  20. Any other condition deemed by the investigator to significantly affect haemostasis, coagulation, bleeding risk or ability to comply with the study protocol.
  21. Females of child-bearing potential unless negative pregnancy test at screening and willing to use effective contraception (i.e. established use of oral, injected or implanted hormonal methods of contraception or placement of an intrauterine device (IUD) or intrauterine system (IUS) or barrier methods of contraception with spermicide or sole male partner with prior vasectomy and confirmed absence of sperm in ejaculate) for the duration of treatment with study medication.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: Aspirin 20mg
Aspirin 75 mg OD for 14(-2) days then aspirin 20 mg BD plus rivaroxaban 2.5 mg BD for 14(-2) days then aspirin 75 mg OD plus rivaroxaban 2.5 mg BD
Aspirin 75mg OD for 14 days
Aspirin 20mg BD for 14 days
Rivaroxaban 2.5mg BD
Other: Asprin 75mg
Aspirin 75 mg OD for 14(-2) days then aspirin 75 mg OD plus rivaroxaban 2.5 mg BD for 14(-2) days then aspirin 20 mg BD plus rivaroxaban 2.5 mg BD
Aspirin 75mg OD for 14 days
Aspirin 20mg BD for 14 days
Rivaroxaban 2.5mg BD

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Bleeding Time Difference
Time Frame: after 14(-2) days on each treatment schedule, bleeding time (seconds) performed 2 hours after the latest dose of aspirin +/- rivaroxaban.
The primary endpoint will be difference in bleeding time, measured at 2 hours post-dose, assessed between aspirin (aspirin lysine) 75 mg once-daily alone vs. aspirin (aspirin lysine) 20 mg twice-daily plus rivaroxaban 2.5 mg twice-daily and aspirin (aspirin lysine) 75 mg once-daily alone vs. aspirin (aspirin lysine) 75 mg once-daily plus rivaroxaban 2.5 mg twice-daily.
after 14(-2) days on each treatment schedule, bleeding time (seconds) performed 2 hours after the latest dose of aspirin +/- rivaroxaban.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Bleeding time pre-dose
Time Frame: Until 14 (-2) days after last IMP dose
A secondary endpoint will be the difference in bleeding time measured at pre-dose
Until 14 (-2) days after last IMP dose
Fibrin clot lag time by fibrin clot turbidimetry
Time Frame: Until 14 (-2) days after last IMP dose
A secondary endpoint will be the difference in fibrin clot lag time at pre-dose and 2 hours post-dose
Until 14 (-2) days after last IMP dose
Fibrin clot lysis time by fibrin clot turbidimetry
Time Frame: Until 14 (-2) days after last IMP dose
A secondary endpoint will be the difference in fibrin lysis lag time at pre-dose and 2 hours post-dose
Until 14 (-2) days after last IMP dose
Plasma TNF by enzyme-linked immunosorbent assay (ELISA)/multiplex bead assay (MBA)
Time Frame: Until 14 (-2) days after last IMP dose
A secondary endpoint will be the difference in Plasma TNF-α at pre-dose and 2 hours post-dose
Until 14 (-2) days after last IMP dose
Plasma IL-6 by ELISA
Time Frame: Until 14 (-2) days after last IMP dose
A secondary endpoint will be the difference in Plasma IL-6 at pre-dose and 2 hours post-dose
Until 14 (-2) days after last IMP dose
Serum CRP (Roche Cobas assay)
Time Frame: Until 14 (-2) days after last IMP dose
A secondary endpoint will be the difference in Serum CRP at 2 hours post-dose
Until 14 (-2) days after last IMP dose
Leukocyte count (and subsets), by automated cell counting
Time Frame: Until 14 (-2) days after last IMP dose
A secondary endpoint will be the difference in Leukocyte count at pre-dose and 2 hours post-dose
Until 14 (-2) days after last IMP dose
Serum TXB2 by ELISA
Time Frame: Until 14 (-2) days after last IMP dose
A secondary endpoint will be the difference in Serum TXB2 at pre-dose and 2 hours post-dose
Until 14 (-2) days after last IMP dose
Urine PGI-M by ELISA
Time Frame: Until 14 (-2) days after last IMP dose
A secondary endpoint will be the difference in Urine PGI-M at pre-dose and 2 hours post-dose
Until 14 (-2) days after last IMP dose
Urine TxM by ELISA
Time Frame: Until 14 (-2) days after last IMP dose
A secondary endpoint will be the difference in Urine TxM at pre-dose and 2 hours post-dose
Until 14 (-2) days after last IMP dose
Platelet aggregation responses to AA, collagen and adenosine diphosphate ADP by light transmittance aggregometry
Time Frame: Until 14 (-2) days after last IMP dose
Mean platelet aggregation responses to arachidonic acid (AA), collagen and adenosine diphosphate (ADP), at pre-dose and 2 hours post-dose
Until 14 (-2) days after last IMP dose
Final clot turbidity by fibrin clot turbidimetry
Time Frame: Until 14 (-2) days after last IMP dose
A secondary endpoint will be the final clot turbidity at pre-dose and 2 hours post-dose
Until 14 (-2) days after last IMP dose

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

August 26, 2021

Primary Completion (Actual)

August 31, 2023

Study Completion (Actual)

December 1, 2023

Study Registration Dates

First Submitted

June 28, 2021

First Submitted That Met QC Criteria

July 27, 2021

First Posted (Actual)

August 4, 2021

Study Record Updates

Last Update Posted (Actual)

February 20, 2026

Last Update Submitted That Met QC Criteria

February 3, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

The data arising from the trial will be owned by University of Sheffield and will not be disseminated to other researchers

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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