View source for HDB Tirofiban decreases rate of periprocedural myocardial infarction compared to placebo in patients with poor responsiveness to clopidogrel and aspirin: Results of the 3T/2R study

''September 2, 2008 by Leah H. Biller'' [mailto:lbiller@wikidoc.org]

'''ESC Congress 2008- Munich, Germany''': Investigators from Italy reported that for poor responders to standard oral [[antiplatelet]] agents, treatment with high-dose bolus (HDB) [[tirofiban]] after elective [[percutaneous coronary intervention]] (PCI) decreased the rate of periprocedural [[myocardial infarction]] compared to placebo.  

The main results of the 3T/2R (Tailoring Treatment with Tirofiban in patients showing Resistance to aspirin or Resistance to clopidogrel) study were presented by Dr. Marco Valgimigli at the ESC 2008 Congress Hot Line Update III Session <ref> [http://www.escardio.org/congresses/esc2008/congress-reports/Pages/3210-3211-valgimigli-verheugt.aspx| ESC 2008 Congress Reports]</ref>.

For patients undergoing PCI, the risk of [[plaque]] rupture has been combated with [[antiplatelet therapy]] as part of standard clinical practice.  Studies have shown, however, that treatment with [[clopidogrel]] and [[aspirin]] (oral antiplatelet drugs) is not uniformly effective for all patients and in fact responsiveness to these drugs is markedly variable; moreover, poor responsiveness to clopidogrel has been linked to stent [[thrombosis]], post-stent [[ischemia|ischemic events]] and periprocedural [[myocardial infarction]] <ref> Angiolillo, DJ et al. Variability in Individual Responsiveness to Clopidogrel Clinical Implications, Management, and Future Perspectives. Journal of the American College of Cardiology. 10 April 2007;49(14):1505-16. </ref>.  The risk of thrombotic events after [[PCI]] has been shown to increase 1.8 to 10 fold for poor responders <ref>[http://www.escardio.org/about/press/press-releases/congress-08/Pages/HotLine3-Valgimigli-antiplatelet.aspx ESC Congress 2008 Press Release]</ref>. While the individual patient’s response to cardiovascular drugs such as anti-[[hypertension]] and lipid lowering has been studied and is considered in planning treatment, individual responsiveness to oral antiplatelet agents has remained largely unaddressed.

The 3T/2R study aimed to investigate the potential role of HDB tirofiban to decrease thrombotic events for those patients with poor response to standard [[clopidogrel]] and [[aspirin]] therapy.  Out of 1277 patients scheduled to undergo elective PCI for stable or low-risk coronary disease at ten European sites, 263 poor responders were selected based on point-of-care [[assay]]s (VerifyNow™ Aspirin and P2Y12 assays (Accumetrics, USA)).  Patients were randomized in a double blind manner to either HDB [[tirofiban]] (25µg/kg in 3 min followed by 14-24 hour infusion at 0.15µg/kg/min) or [[placebo]] with standard [[clopidogrel]] and [[aspirin]]. The primary endpoint was an increase in [[Troponin]] I or [[T wave|T elevation]] greater than 3 times the upper limit of normal (ULN) within 48 hours post-PCI, indicating a periprocedural [[myocardial infarction]] according to the universal definition.  

Patients receiving HDB [[tirofiban]] had a decreased rate of periprocedural [[myocardial infarction]] compared to those receiving [[placebo]] plus standard therapy (20.4% versus 35.1% respectively; Relative Risk Reduction = 42%; 95% CI = 61-12; p = 0.009 for superiority). At 30-day follow-up, the HDB [[tirofiban]] group had a significant reduction in major adverse cardiovascular events (21.2% versus 36.6% for the placebo plus standard therapy group, p = 0.0065).  [[Bleeding]] rates were low in both trial arms and not significantly different.
 
The findings of the 3T/2R study suggest the importance of considering individual patients’ responsiveness to standard antiplatelet therapy (via point-of care assays); moreover, the results demonstrate proof of concept for the potential of HDB [[tirofiban]] treatment in poor responders.  Further investigation should utilize additional methods of testing for [[clopidogrel]] and [[aspirin]] responsiveness.

The 3T/2R study was sponsored by the University of Ferrara, Italy.  The study was supported in part by an unrestricted research grant from Merck, USA and Iroko, USA.

==References==
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