Coronary SyndromePhase 4WILLOW CCSNCT04990791
WILL lOWer Dose Aspirin be Better With Rivaroxaban in Patients With Chronic Coronary Syndromes?
A Phase 4 study testing Aspirin 75mg, Aspirin 20mg and Rivaroxaban 2.5 mg in people with Coronary Syndrome, run by Sheffield Teaching Hospitals NHS Foundation Trust at 1 site in United Kingdom.
Trial summary
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… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Coronary Syndrome
- What is being tested?
- Aspirin 75mg, Aspirin 20mg and Rivaroxaban 2.5 mg
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 48 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 26 Aug 2021to 1 Dec 2023
- Phase
- Phase 4
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Provision of informed consent prior to any study specific procedures
- Male or female aged greater than 18 years
- Existing diagnosis of a chronic coronary syndrome:
- 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
- Receiving single antiplatelet therapy with aspirin 75 mg once daily
Who cannot join
- Any history of haemorrhagic stroke or lacunar stroke
- History of ischaemic stroke or transient ischaemic attack in the last year
- Heart failure associated with NYHA class III or IV symptoms
- Estimated glomerular filtration rate <15 ml/min
- Planned procedure for coronary revascularization
- Any planned surgery or other procedure that may require suspension or discontinuation of antiplatelet therapy expected to occur within 3 months of randomisation
Show all 21Show fewer
- Prior intention by patient or physician to discontinue aspirin within the study period
- Receiving doses of aspirin other than 75 mg once daily
- Treatment or planned treatment with antiplatelet medication apart from aspirin (eg. clopidogrel, prasugrel, ticagrelor, dipyridamole, ticlopidine)
- Current use of a loop, thiazide or potassium sparing diuretic (affects prostanoid assays)
- Any acute coronary syndrome event, percutaneous coronary intervention or coronary artery bypass grafting within 1 year prior to randomisation
- 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)
- Current or planned use of a GPIIb/IIIa inhibitor (eg. abciximab, tirofiban)
- Current or planned use of a fibrinolytic agent (eg. tissue plasminogen activator)
- 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
- 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).
- 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.
- 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
- Co-morbidity associated with life expectancy less than 1 year
- Any other condition deemed by the investigator to significantly affect haemostasis, coagulation, bleeding risk or ability to comply with the study protocol.
- 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.
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
Sheffield Teaching Hospitals NHS Foundation Trust
Sheffield, South Yorkshire, S5 7AU
About this study
Official title: 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.
Read more
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.
Read the 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:
- 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.
- 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.
- 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
- Conditions
- Coronary Syndrome
- Being tested
- Aspirin 75mg, Aspirin 20mg, Rivaroxaban 2.5 mg
- Medical subject headings
- Angina, Unstable
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Aspirin 75mgDrug
Aspirin 75mg OD for 14 days
Aspirin 20mgDrug
Aspirin 20mg BD for 14 days
Rivaroxaban 2.5 mgDrug
Rivaroxaban 2.5mg BD
| Study group | Role | What they receive |
|---|---|---|
| Aspirin 20mg | Other | 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 Receives: Drug: Aspirin 75mg; Drug: Aspirin 20mg; Drug: Rivaroxaban 2.5 mg |
| Asprin 75mg | Other | 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 Receives: Drug: Aspirin 75mg; Drug: Aspirin 20mg; Drug: Rivaroxaban 2.5 mg |
What is being measured
The primary outcome is the main question the study is designed to answer.
Bleeding Time Difference
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.
Measured: after 14(-2) days on each treatment schedule, bleeding time (seconds) performed 2 hours after the latest dose of aspirin +/- rivaroxaban.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Aug 2021
- Study start26 Aug 2021
- Primary completion31 Aug 2023
- Study completion1 Dec 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (19)Papers the sponsor has linked to this study.
- Other trials for Coronary SyndromeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Randomised controlled open-label crossover study
- Masking
- None (open label)
- Enrolment
- 48 participants (actual)
Sponsor and investigators
- Lead sponsor
- Sheffield Teaching Hospitals NHS Foundation Trust
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04990791
- Sponsor's protocol ID
- STH20412
- Acronym
- WILLOW CCS
- Status last verified
- Feb 2026
- First submitted
- 28 Jun 2021
- Last updated
- 20 Feb 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: The data arising from the trial will be owned by University of Sheffield and will not be disseminated to other researchers
Publications
Task Force Members; Montalescot G, Sechtem U, Achenbach S, Andreotti F, Arden C, Budaj A, Bugiardini R, Crea F, Cuisset T, Di Mario C, Ferreira JR, Gersh BJ, Gitt AK, Hulot JS, Marx N, Opie LH, Pfisterer M, Prescott E, Ruschitzka F, Sabate M, Senior R, Taggart DP, van der Wall EE, Vrints CJ; ESC Committee for Practice Guidelines; Zamorano JL, Achenbach S, Baumgartner H, Bax JJ, Bueno H, Dean V, Deaton C, Erol C, Fagard R, Ferrari R, Hasdai D, Hoes AW, Kirchhof P, Knuuti J, Kolh P, Lancellotti P, Linhart A, Nihoyannopoulos P, Piepoli MF, Ponikowski P, Sirnes PA, Tamargo JL, Tendera M, Torbicki A, Wijns W, Windecker S; Document Reviewers; Knuuti J, Valgimigli M, Bueno H, Claeys MJ, Donner-Banzhoff N, Erol C, Frank H, Funck-Brentano C, Gaemperli O, Gonzalez-Juanatey JR, Hamilos M, Hasdai D, Husted S, James SK, Kervinen K, Kolh P, Kristensen SD, Lancellotti P, Maggioni AP, Piepoli MF, Pries AR, Romeo F, Ryden L, Simoons ML, Sirnes PA, Steg PG, Timmis A, Wijns W, Windecker S, Yildirir A, Zamorano JL. 2013 ESC guidelines on the management of stable coronary artery disease: the Task Force on the management of stable coronary artery disease of the European Society of Cardiology. Eur Heart J. 2013 Oct;34(38):2949-3003. doi: 10.1093/eurheartj/eht296. Epub 2013 Aug 30. No abstract available.
PubMed 23996286Knuuti J, Wijns W, Saraste A, Capodanno D, Barbato E, Funck-Brentano C, Prescott E, Storey RF, Deaton C, Cuisset T, Agewall S, Dickstein K, Edvardsen T, Escaned J, Gersh BJ, Svitil P, Gilard M, Hasdai D, Hatala R, Mahfoud F, Masip J, Muneretto C, Valgimigli M, Achenbach S, Bax JJ; ESC Scientific Document Group. 2019 ESC Guidelines for the diagnosis and management of chronic coronary syndromes. Eur Heart J. 2020 Jan 14;41(3):407-477. doi: 10.1093/eurheartj/ehz425. No abstract available.
PubMed 31504439Eikelboom JW, Connolly SJ, Bosch J, Dagenais GR, Hart RG, Shestakovska O, Diaz R, Alings M, Lonn EM, Anand SS, Widimsky P, Hori M, Avezum A, Piegas LS, Branch KRH, Probstfield J, Bhatt DL, Zhu J, Liang Y, Maggioni AP, Lopez-Jaramillo P, O'Donnell M, Kakkar AK, Fox KAA, Parkhomenko AN, Ertl G, Stork S, Keltai M, Ryden L, Pogosova N, Dans AL, Lanas F, Commerford PJ, Torp-Pedersen C, Guzik TJ, Verhamme PB, Vinereanu D, Kim JH, Tonkin AM, Lewis BS, Felix C, Yusoff K, Steg PG, Metsarinne KP, Cook Bruns N, Misselwitz F, Chen E, Leong D, Yusuf S; COMPASS Investigators. Rivaroxaban with or without Aspirin in Stable Cardiovascular Disease. N Engl J Med. 2017 Oct 5;377(14):1319-1330. doi: 10.1056/NEJMoa1709118. Epub 2017 Aug 27.
PubMed 28844192Sumaya W, Wallentin L, James SK, Siegbahn A, Gabrysch K, Bertilsson M, Himmelmann A, Ajjan RA, Storey RF. Fibrin clot properties independently predict adverse clinical outcome following acute coronary syndrome: a PLATO substudy. Eur Heart J. 2018 Apr 1;39(13):1078-1085. doi: 10.1093/eurheartj/ehy013.
PubMed 29390064Konigsbrugge O, Weigel G, Quehenberger P, Pabinger I, Ay C. Plasma clot formation and clot lysis to compare effects of different anticoagulation treatments on hemostasis in patients with atrial fibrillation. Clin Exp Med. 2018 Aug;18(3):325-336. doi: 10.1007/s10238-018-0490-9. Epub 2018 Feb 7.
PubMed 29417256Patrono C, Morais J, Baigent C, Collet JP, Fitzgerald D, Halvorsen S, Rocca B, Siegbahn A, Storey RF, Vilahur G. Antiplatelet Agents for the Treatment and Prevention of Coronary Atherothrombosis. J Am Coll Cardiol. 2017 Oct 3;70(14):1760-1776. doi: 10.1016/j.jacc.2017.08.037.
PubMed 28958334Patrono C. Aspirin as an antiplatelet drug. N Engl J Med. 1994 May 5;330(18):1287-94. doi: 10.1056/NEJM199405053301808. No abstract available.
PubMed 8145785Ajjan RA, Standeven KF, Khanbhai M, Phoenix F, Gersh KC, Weisel JW, Kearney MT, Ariens RA, Grant PJ. Effects of aspirin on clot structure and fibrinolysis using a novel in vitro cellular system. Arterioscler Thromb Vasc Biol. 2009 May;29(5):712-7. doi: 10.1161/ATVBAHA.109.183707. Epub 2009 Mar 12.
PubMed 19286636Kiers D, van der Heijden WA, van Ede L, Gerretsen J, de Mast Q, van der Ven AJ, El Messaoudi S, Rongen GA, Gomes M, Kox M, Pickkers P, Riksen NP. A randomised trial on the effect of anti-platelet therapy on the systemic inflammatory response in human endotoxaemia. Thromb Haemost. 2017 Aug 30;117(9):1798-1807. doi: 10.1160/TH16-10-0799. Epub 2017 Jul 6.
PubMed 28692111Thomas MR, Outteridge SN, Ajjan RA, Phoenix F, Sangha GK, Faulkner RE, Ecob R, Judge HM, Khan H, West LE, Dockrell DH, Sabroe I, Storey RF. Platelet P2Y12 Inhibitors Reduce Systemic Inflammation and Its Prothrombotic Effects in an Experimental Human Model. Arterioscler Thromb Vasc Biol. 2015 Dec;35(12):2562-70. doi: 10.1161/ATVBAHA.115.306528. Epub 2015 Oct 29.
PubMed 26515417Ridker PM, Everett BM, Thuren T, MacFadyen JG, Chang WH, Ballantyne C, Fonseca F, Nicolau J, Koenig W, Anker SD, Kastelein JJP, Cornel JH, Pais P, Pella D, Genest J, Cifkova R, Lorenzatti A, Forster T, Kobalava Z, Vida-Simiti L, Flather M, Shimokawa H, Ogawa H, Dellborg M, Rossi PRF, Troquay RPT, Libby P, Glynn RJ; CANTOS Trial Group. Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease. N Engl J Med. 2017 Sep 21;377(12):1119-1131. doi: 10.1056/NEJMoa1707914. Epub 2017 Aug 27.
PubMed 28845751Teng R, Maya J, Butler K. Evaluation of the pharmacokinetics and pharmacodynamics of ticagrelor co-administered with aspirin in healthy volunteers. Platelets. 2013;24(8):615-24. doi: 10.3109/09537104.2012.748185. Epub 2012 Dec 18.
PubMed 23249161Choi J, Hwang SY, Ahn K. Interplay between RNASEH2 and MOV10 controls LINE-1 retrotransposition. Nucleic Acids Res. 2018 Feb 28;46(4):1912-1926. doi: 10.1093/nar/gkx1312.
PubMed 29315404Ghys T, Malfait R, VAN den Bossche J. Performance evaluation of the Sysmex XS-1000i automated haematology analyser. Int J Lab Hematol. 2009 Oct;31(5):560-6. doi: 10.1111/j.1751-553X.2008.01081.x. Epub 2009 Jun 18.
PubMed 18616754Parker WAE, Orme RC, Hanson J, Stokes HM, Bridge CM, Shaw PA, Sumaya W, Thorneycroft K, Petrucci G, Porro B, Judge HM, Ajjan RA, Rocca B, Storey RF. Very-low-dose twice-daily aspirin maintains platelet inhibition and improves haemostasis during dual-antiplatelet therapy for acute coronary syndrome. Platelets. 2019;30(2):148-157. doi: 10.1080/09537104.2019.1572880. Epub 2019 Feb 13.
PubMed 30759035
Study at a glance
From the registry record, last updated by the sponsor on 20 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- 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?
- ClinicalTrials.gov ID
- NCT04990791
- Acronym / sponsor ID
- WILLOW CCS / STH20412
- Conditions
- Coronary Syndrome
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 48 participants (actual)
- Lead sponsor
- Sheffield Teaching Hospitals NHS Foundation TrustUniversity, hospital or other
- Study start
- 26 Aug 2021 (actual)
- Primary completion
- 31 Aug 2023 (actual)
- Study completion
- 1 Dec 2023 (actual)
- First posted
- 4 Aug 2021 (actual)
- Results
- Posted 20 Feb 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
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:
- 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.
- 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.
- 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 design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Randomised controlled open-label crossover study
| Arm | Type | Receives |
|---|---|---|
| Aspirin 20mg | Other | Drug: Aspirin 75mg, Drug: Aspirin 20mg, Drug: Rivaroxaban 2.5 mgAspirin 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 |
| Asprin 75mg | Other | Drug: Aspirin 75mg, Drug: Aspirin 20mg, Drug: Rivaroxaban 2.5 mgAspirin 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 |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Provision of informed consent prior to any study specific procedures
- Male or female aged greater than 18 years
- Existing diagnosis of a chronic coronary syndrome:
- Receiving single antiplatelet therapy with aspirin 75 mg once daily
Key exclusion criteria (21 listed)
- Any history of haemorrhagic stroke or lacunar stroke
- History of ischaemic stroke or transient ischaemic attack in the last year
- Heart failure associated with NYHA class III or IV symptoms
- Estimated glomerular filtration rate <15 ml/min
- Planned procedure for coronary revascularization
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Aspirin 75mgAspirin 75mg OD for 14 days | Drug | Aspirin 20mg, Asprin 75mg |
| Aspirin 20mgAspirin 20mg BD for 14 days | Drug | Aspirin 20mg, Asprin 75mg |
| Rivaroxaban 2.5 mgRivaroxaban 2.5mg BD | Drug | Aspirin 20mg, Asprin 75mg |
Primary outcome
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.
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Feb 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Background: PubMed 23996286Task Force Members; Montalescot G, Sechtem U, Achenbach S, Andreotti F, Arden C, Budaj A, Bugiardini R, Crea F, Cuisset T, Di Mario C, Ferreira JR, Gersh BJ, Gitt AK, Hulot JS, Marx N, Opie LH, Pfisterer M, Prescott E, Ruschitzka F, Sabate M, Senior R, Taggart DP, van der Wall EE, Vrints CJ; ESC Committee for Practice Guidelines; Zamorano JL, Achenbach S, Baumgartner H, Bax JJ, Bueno H, Dean V, Deaton C, Erol C, Fagard R, Ferrari R, Hasdai D, Hoes AW, Kirchhof P, Knuuti J, Kolh P, Lancellotti P, Linhart A, Nihoyannopoulos P, Piepoli MF, Ponikowski P, Sirnes PA, Tamargo JL, Tendera M, Torbicki A, Wijns W, Windecker S; Document Reviewers; Knuuti J, Valgimigli M, Bueno H, Claeys MJ, Donner-Banzhoff N, Erol C, Frank H, Funck-Brentano C, Gaemperli O, Gonzalez-Juanatey JR, Hamilos M, Hasdai D, Husted S, James SK, Kervinen K, Kolh P, Kristensen SD, Lancellotti P, Maggioni AP, Piepoli MF, Pries AR, Romeo F, Ryden L, Simoons ML, Sirnes PA, Steg PG, Timmis A, Wijns W, Windecker S, Yildirir A, Zamorano JL. 2013 ESC guidelines on the management of stable coronary artery disease: the Task Force on the management of stable coronary artery disease of the European Society of Cardiology. Eur Heart J. 2013 Oct;34(38):2949-3003. doi: 10.1093/eurheartj/eht296. Epub 2013 Aug 30. No abstract available.
- Background: PubMed 31504439Knuuti J, Wijns W, Saraste A, Capodanno D, Barbato E, Funck-Brentano C, Prescott E, Storey RF, Deaton C, Cuisset T, Agewall S, Dickstein K, Edvardsen T, Escaned J, Gersh BJ, Svitil P, Gilard M, Hasdai D, Hatala R, Mahfoud F, Masip J, Muneretto C, Valgimigli M, Achenbach S, Bax JJ; ESC Scientific Document Group. 2019 ESC Guidelines for the diagnosis and management of chronic coronary syndromes. Eur Heart J. 2020 Jan 14;41(3):407-477. doi: 10.1093/eurheartj/ehz425. No abstract available.
- Background: PubMed 28844192Eikelboom JW, Connolly SJ, Bosch J, Dagenais GR, Hart RG, Shestakovska O, Diaz R, Alings M, Lonn EM, Anand SS, Widimsky P, Hori M, Avezum A, Piegas LS, Branch KRH, Probstfield J, Bhatt DL, Zhu J, Liang Y, Maggioni AP, Lopez-Jaramillo P, O'Donnell M, Kakkar AK, Fox KAA, Parkhomenko AN, Ertl G, Stork S, Keltai M, Ryden L, Pogosova N, Dans AL, Lanas F, Commerford PJ, Torp-Pedersen C, Guzik TJ, Verhamme PB, Vinereanu D, Kim JH, Tonkin AM, Lewis BS, Felix C, Yusoff K, Steg PG, Metsarinne KP, Cook Bruns N, Misselwitz F, Chen E, Leong D, Yusuf S; COMPASS Investigators. Rivaroxaban with or without Aspirin in Stable Cardiovascular Disease. N Engl J Med. 2017 Oct 5;377(14):1319-1330. doi: 10.1056/NEJMoa1709118. Epub 2017 Aug 27.
- Background: PubMed 29390064Sumaya W, Wallentin L, James SK, Siegbahn A, Gabrysch K, Bertilsson M, Himmelmann A, Ajjan RA, Storey RF. Fibrin clot properties independently predict adverse clinical outcome following acute coronary syndrome: a PLATO substudy. Eur Heart J. 2018 Apr 1;39(13):1078-1085. doi: 10.1093/eurheartj/ehy013.
- Background: PubMed 29417256Konigsbrugge O, Weigel G, Quehenberger P, Pabinger I, Ay C. Plasma clot formation and clot lysis to compare effects of different anticoagulation treatments on hemostasis in patients with atrial fibrillation. Clin Exp Med. 2018 Aug;18(3):325-336. doi: 10.1007/s10238-018-0490-9. Epub 2018 Feb 7.
- Background: PubMed 28958334Patrono C, Morais J, Baigent C, Collet JP, Fitzgerald D, Halvorsen S, Rocca B, Siegbahn A, Storey RF, Vilahur G. Antiplatelet Agents for the Treatment and Prevention of Coronary Atherothrombosis. J Am Coll Cardiol. 2017 Oct 3;70(14):1760-1776. doi: 10.1016/j.jacc.2017.08.037.
- Background: PubMed 8145785Patrono C. Aspirin as an antiplatelet drug. N Engl J Med. 1994 May 5;330(18):1287-94. doi: 10.1056/NEJM199405053301808. No abstract available.
- Background: PubMed 19286636Ajjan RA, Standeven KF, Khanbhai M, Phoenix F, Gersh KC, Weisel JW, Kearney MT, Ariens RA, Grant PJ. Effects of aspirin on clot structure and fibrinolysis using a novel in vitro cellular system. Arterioscler Thromb Vasc Biol. 2009 May;29(5):712-7. doi: 10.1161/ATVBAHA.109.183707. Epub 2009 Mar 12.
- Background: PubMed 28692111Kiers D, van der Heijden WA, van Ede L, Gerretsen J, de Mast Q, van der Ven AJ, El Messaoudi S, Rongen GA, Gomes M, Kox M, Pickkers P, Riksen NP. A randomised trial on the effect of anti-platelet therapy on the systemic inflammatory response in human endotoxaemia. Thromb Haemost. 2017 Aug 30;117(9):1798-1807. doi: 10.1160/TH16-10-0799. Epub 2017 Jul 6.
- Background: PubMed 26515417Thomas MR, Outteridge SN, Ajjan RA, Phoenix F, Sangha GK, Faulkner RE, Ecob R, Judge HM, Khan H, West LE, Dockrell DH, Sabroe I, Storey RF. Platelet P2Y12 Inhibitors Reduce Systemic Inflammation and Its Prothrombotic Effects in an Experimental Human Model. Arterioscler Thromb Vasc Biol. 2015 Dec;35(12):2562-70. doi: 10.1161/ATVBAHA.115.306528. Epub 2015 Oct 29.
- Background: PubMed 28845751Ridker PM, Everett BM, Thuren T, MacFadyen JG, Chang WH, Ballantyne C, Fonseca F, Nicolau J, Koenig W, Anker SD, Kastelein JJP, Cornel JH, Pais P, Pella D, Genest J, Cifkova R, Lorenzatti A, Forster T, Kobalava Z, Vida-Simiti L, Flather M, Shimokawa H, Ogawa H, Dellborg M, Rossi PRF, Troquay RPT, Libby P, Glynn RJ; CANTOS Trial Group. Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease. N Engl J Med. 2017 Sep 21;377(12):1119-1131. doi: 10.1056/NEJMoa1707914. Epub 2017 Aug 27.
- Background: PubMed 23249161Teng R, Maya J, Butler K. Evaluation of the pharmacokinetics and pharmacodynamics of ticagrelor co-administered with aspirin in healthy volunteers. Platelets. 2013;24(8):615-24. doi: 10.3109/09537104.2012.748185. Epub 2012 Dec 18.
- Individual participant dataSharing planned: No. The data arising from the trial will be owned by University of Sheffield and will not be disseminated to other researchers
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Aspirin 75mg, Aspirin 20mg and Rivaroxaban 2.5 mg in people with Coronary Syndrome, run by Sheffield Teaching Hospitals NHS Foundation Trust at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 21 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 20 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 20 Feb 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
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.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04990791, which also lists 19 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Feb 2026.