Checking how well clopidogrel works in people with essential thrombocythemia
Measures platelet response to clopidogrel in adults with essential thrombocythemia.
Plain-language title generated from the registry record
Registry title: CRETA (Clopidogrel Responsiveness in Essential ThrombocithemiA)
Key facts
- Where
- Pescara and Torino, ItalySee the 2 sites
Where in Italy
- Azienda USL di Pescara - Ospedale Santo SpiritoPescara, ItalyNo longer taking part
- AOU Città della Salute e della Scienza di TorinoTorino, ItalyNo longer taking part
Questions to ask the study team
- How often do I need to come in, and for how long each time?
- Are travel costs paid?
- Can I keep my own doctor?
- What happens if I want to stop?
Trial details
- Who runs it
- Fondazione Policlinico Universitario Agostino Gemelli IRCCS
- Trial code
- NCT07645755
- Record updated
- 12 June 2026
- Original description
Essential thrombocythemia (ET) is a chronic myeloproliferative neoplasm associated with increased platelet production and activation, leading to a high risk of thrombotic complications. Low-dose aspirin is the standard antiplatelet therapy for thrombosis prevention; however, the accelerated platelet turnover characteristic of ET results in rapid recovery of platelet function, making once-daily aspirin insufficient in many patients. Consequently, twice-daily low-dose aspirin is currently recommended to achieve adequate and sustained platelet inhibition.Read full original descriptionShow less
Evaluation of Response to Clopidogrel in Patients With Essential Thrombocythemia
Essential thrombocythemia (ET) is a chronic myeloproliferative neoplasm associated with increased platelet production and activation, leading to a high risk of thrombotic complications. Low-dose aspirin is the standard antiplatelet therapy for thrombosis prevention; however, the accelerated platelet turnover characteristic of ET results in rapid recovery of platelet function, making once-daily aspirin insufficient in many patients. Consequently, twice-daily low-dose aspirin is currently recommended to achieve adequate and sustained platelet inhibition.
For patients intolerant to aspirin, clopidogrel 75 mg/day is the approved alternative. Clopidogrel irreversibly inhibits the platelet P2Y12 receptor, but its pharmacodynamic effect is highly variable because it is a prodrug requiring metabolic activation. Studies in non-ET populations have shown that higher clopidogrel doses (150 mg/day) provide stronger and more consistent platelet inhibition without significantly increasing bleeding risk.
Evidence on clopidogrel use in ET is limited, but available data suggest that standard-dose therapy may result in inadequate platelet inhibition, potentially reducing antithrombotic efficacy. Platelet function testing can identify patients with high residual platelet reactivity ("poor responders"), who may benefit from dose escalation. Therefore, in ET patients requiring clopidogrel therapy, assessment of platelet responsiveness may help optimize treatment, ensuring adequate platelet inhibition and potentially improving protection against thrombotic events.
Inclusion: Male or female subjects age ≥ 18 years; Confirmed diagnosis of ET according to the 2022 WHO classification criteria30; Patients treated with clopidogrel 75 mg od as antithrombotic prophylaxis since at least 3 weeks, as per the indication of the referring hematologist; Ability to understand the nature of the study and voluntarily provide written informed consent patients whose responsiveness to the standard clopidogrel regimen was determined, based on clinical practice, using the VN-P2Y12 method.
Exclusion: Need for anticoagulant therapy; Concomitant use of other antiplatelet agents; Chronic use of non-steroidal anti-inflammatory drugs (NSAIDs) (i.e > 3 days per week); Chronic corticosteroid therapy exceeding a daily dose equivalent to prednisone 5 mg; Platelet count >1,000,000/μL on three separate determinations within the 2 months prior to enrollment.