Vorapaxar for secondary prevention of thrombotic events for patients with previous myocardial infarction: a prespecified subgroup analysis of the TRA 2°P-TIMI 50 trial.

Abstract

BACKGROUND:

Vorapaxar inhibits platelet activation by antagonising thrombin-mediated activation of the protease-activated receptor 1 on human platelets. The effect of adding other antiplatelet drugs to aspirin for long-term secondary prevention of thrombotic events in stable patients with previous myocardial infarction is uncertain. We tested this effect in a subgroup of patients from the Thrombin Receptor Antagonist in Secondary Prevention of Atherothrombotic Ischemic Events (TRA 2°P)-TIMI 50 trial.

METHODS:

In TRA 2°P-TIMI 50--a randomised, placebo-controlled, parallel trial--we randomly assigned patients with a history of atherothrombosis to receive vorapaxar (2·5 mg daily) or matching placebo in a 1:1 ratio. Patients, and those giving treatment, assessing outcomes, and analysing results were masked to treatment allocation. Patients with a qualifying myocardial infarction within the previous 2 weeks to 12 months were analysed as a pre-defined subgroup. The primary efficacy endpoint was cardiovascular death, myocardial infarction, or stroke, analysed by intention to treat. We analysed events by Kaplan-Meier analysis and compared groups with a Cox proportional hazard model. TRA 2°P-TIMI 50 is registered at ClinicalTrials.gov (NCT00526474).

FINDINGS:

17,779 of 26,449 patients had a qualifying myocardial infarction and were assigned treatment (8898 to vorapaxar and 8881 to placebo). Median follow-up was 2·5 years (IQR 2·0-2·9). Cardiovascular death, myocardial infarction, or stroke occurred in 610 of 8898 patients in the vorapaxar group and 750 of 8881 in the placebo group (3-year Kaplan-Meier estimates 8·1%vs 9·7%, HR 0·80, 95% CI 0·72-0·89; p<0·0001). Moderate or severe bleeding was more common in the vorapaxar group versus the placebo group (241/8880 [3·4%, 3-year Kaplan-Meier estimate] vs 151/8849 [2·1%, 3-year Kaplan-Meier estimate], HR 1·61, 95% CI 1·31-1·97; p<0·0001). Intracranial haemorrhage occurred in 43 of 8880 patients (0·6%, 3-year Kaplan-Meier estimate) with vorapaxar versus 28 of 8849 (0·4%, 3-year Kaplan-Meier estimate) with placebo (p=0·076). Other serious adverse events were equally distributed between groups.

INTERPRETATION:

For patients with a history of myocardial infarction, inhibition of protease-activated receptor 1 with vorapaxar reduces the risk of cardiovascular death or ischaemic events when added to standard antiplatelet treatment, including aspirin, and increases the risk of moderate or severe bleeding.

FUNDING:

Merck.

• Authors: Benjamin M Scirica, Marc P Bonaca, Eugene Braunwald, Gaetano M De Ferrari, Daniel Isaza, Basil S Lewis, Felix Mehrhof, Piera A Merlini, Sabina A Murphy, Marc S Sabatine, Michal Tendera, Frans Van de Werf, Robert Wilcox, David A Morrow, TRA 2°P-TIMI 50 Steering Committee Investigators
• Journal: Lancet (London, England) (Lancet) Vol. 380 Issue 9850 Pg. 1317-24 (Oct 13 2012) ISSN: 1474-547X [Electronic] England
• PMID: 22932716 (Publication Type: Journal Article, Multicenter Study, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2012 Elsevier Ltd. All rights reserved.

Chemical References

• Lactones
• Pyridines
• Receptor, PAR-1
• vorapaxar

Topics

• Aged
• Cardiovascular Diseases (mortality)
• Double-Blind Method
• Female
• Humans
• Lactones (adverse effects, therapeutic use)
• Male
• Middle Aged
• Myocardial Infarction
• Pyridines (adverse effects, therapeutic use)
• Receptor, PAR-1 (antagonists & inhibitors)
• Secondary Prevention
• Stroke (etiology, prevention & control)
• Thrombosis (complications, etiology, prevention & control)