Comparative effectiveness of upstream glycoprotein IIb/IIIa inhibitors in patients with moderate- and high-risk acute coronary syndromes: an Acute Catheterization and Urgent Intervention Triage Strategy (ACUITY) substudy.

BACKGROUND: Tirofiban and eptifibatide are both small-molecule, competitive glycoprotein IIb/IIIa receptor inhibitors (GPIs) that are guideline-supported for upstream therapy in acute coronary syndromes (ACS). This study sought to compare the efficacy and safety of tirofiban and eptifibatide in patients with ACS. METHODS: Within the ACUITY trial, 4,323 patients with moderate- and high-risk ACS received upstream, adjunctive GPI (tirofiban or eptifibatide) in addition to an antithrombin. Primary outcomes included 30-day rates of composite major adverse cardiac events (MACE), major bleeding (not related to coronary artery bypass grafting), and composite net adverse clinical events (NACE). The outcomes were compared based on the upstream GPI administered. RESULTS: There were significant differences in the baseline characteristics of patients treated with tirofiban vs eptifibatide, particularly related to country/region. In unadjusted analyses, treatment with upstream tirofiban vs eptifibatide was associated with similar rates of major bleeding (5.8% vs 6.5%, P = .39) and nonsignificantly lower rates of MACE (6.1% vs 7.6%, P = .06) and NACE (10.6% vs 12.6%, P = .06). After propensity-based multivariable adjustment, there were no significant differences between tirofiban and eptifibatide with respect to 30-day major bleeding, MACE, or NACE. CONCLUSIONS: Among more than 4,000 patients with moderate- and high-risk ACS treated with upstream GPI as part of an early invasive management strategy, the use of tirofiban and eptifibatide resulted in similar clinical outcomes. These data suggest equivalence of these 2 agents for upstream use, while highlighting some of the difficulties of nonrandomized comparative effectiveness analyses, specifically the difficulty in addressing geographic differences in the use of nonrandomized treatments.

Predictive value of C-reactive protein on 30-day and 1-year mortality in acute coronary syndromes: an analysis from the ACUITY trial.

We sought to evaluate the association between C-reactive protein (CRP) sampled on admission and short- and long-term mortality in patients with acute coronary syndromes (ACS) undergoing early invasive treatment. Baseline levels of CRP were determined in 2,974 patients with moderate and high-risk ACS undergoing an early invasive treatment strategy in the large-scale randomized ACUITY trial. The relationship of CRP to 30-day and 1-year clinical outcomes were assessed according to quartiles of CRP values. Patients with CRP levels in the fourth quartile compared to the first quartile had significantly higher 30-day mortality (2.3 vs. 0.3%, P = 0.0004) and 1-year mortality (5.5 vs. 2.8%, P = 0.0003). CRP level as a continuous variable was associated with 30-day mortality (OR [95% CI] for one unit increase in logarithmically transformed CRP level = 1.42 [1.08-1.89], P = 0.01) and 1-year mortality (OR [95% CI] = 1.24, [1.04-1.47], P = 0.02). By multivariable analysis, higher baseline CRP levels independently predicted 30-day and 1-year mortality, a relationship that was particularly strong for patients with the highest quartile of CRP (OR [95% CI] = 5.19 [1.14-23.68], P = 0.009). In troponin-positive patients, increasing quartiles of CRP were associated with a trend for 30-day mortality (P (trend) = 0.08) and a significant increase in 1-year mortality (P (trend) = 0.02); this relationship was not present in troponin-negative patients. Baseline CRP level is a powerful independent predictor of both early and late mortality in patients with ACS being treated with an early invasive strategy, especially in troponin positive patients.

Dimorphic Plasmodium falciparum merozoite surface protein-1 epitopes turn off memory T cells and interfere with T cell priming.

The leading blood-stage malaria vaccine candidate antigen, Plasmodium falciparum merozoite surface protein-1 (MSP-1) occurs in two major allelic types worldwide. The molecular basis promoting this stable dimorphism is unknown. In this study, we have shown that allelic altered peptide ligand (APL) T cell epitopes of MSP-1 mutually inhibited IFN-gamma secretion as well as proliferation of CD4+ T cells in 27/34 malaria exposed Gambian volunteers. Besides this inhibition of malaria-specific immunity, the same variant epitopes were also able to impair the priming of human T cells in malaria naive individuals. Epitope variants capable of interfering with T cell priming as well as inhibiting memory T cell effector functions offer a uniquely potent combination for immune evasion. Indeed, enhanced co-habitation of parasites bearing such antagonistic allelic epitope regions was observed in a study of 321 West African children, indicating a survival advantage for parasites able to engage this inhibitory immune interference mechanism.

Induction of T helper type 1 and 2 responses to 19-kilodalton merozoite surface protein 1 in vaccinated healthy volunteers and adults naturally exposed to malaria.

Plasmodium falciparum malaria is a major cause of death in the tropics. The 19-kDa subunit of P. falciparum merozoite surface protein 1 (MSP-1(19)), a major blood stage vaccine candidate, is the target of cellular and humoral immune responses in animals and humans. In this phase I trial of MSP-1(19), immunization of nonexposed human volunteers with either of the two allelic forms of recombinant MSP-1(19) induced high levels of antigen-specific Th1 (gamma interferon) and Th2 (interleukin 4 [IL-4] and IL-10) type lymphokines. The adjustment of the antigen dose and number of immunizations regulated the level of specificity of immune responses and Th1/Th2 bias of responses induced by vaccination. Novel conserved and allelic T-cell epitopes which induced cross-strain immune responses were identified. Importantly, responses to many of these novel epitopes were also present in adults exposed to malaria, both in east (Kenya) and west Africa (The Gambia). These data suggest that epitope-specific naturally acquired MSP-1(19) immune responses in endemic populations can be boosted by vaccination.