Myeloperoxidase as a Promising Therapeutic Target after Myocardial Infarction.

Coronary artery disease (CAD) and myocardial infarction (MI) remain leading causes of death and disability worldwide. CAD begins with the formation of atherosclerotic plaques within the intimal layer of the coronary arteries, a process driven by persistent arterial inflammation and oxidation. Myeloperoxidase (MPO), a mammalian haem peroxidase enzyme primarily expressed within neutrophils and monocytes, has been increasingly recognised as a key pro-inflammatory and oxidative enzyme promoting the development of vulnerable coronary atherosclerotic plaques that are prone to rupture, and can precipitate a MI. Mounting evidence also implicates a pathogenic role for MPO in the inflammatory process that follows a MI, which is characterised by the rapid infiltration of activated neutrophils into the damaged myocardium and the release of MPO. Excessive and persistent cardiac inflammation impairs normal cardiac healing post-MI, resulting in adverse cardiac outcomes and poorer long-term cardiac function, and eventually heart failure. This review summarises the evidence for MPO as a significant oxidative enzyme contributing to the inappropriate inflammatory responses driving the progression of CAD and poor cardiac healing after a MI. It also details the proposed mechanisms underlying MPO's pathogenic actions and explores MPO as a novel therapeutic target for the treatment of unstable CAD and cardiac damage post-MI.

A new proposal for randomized start design to investigate disease-modifying therapies for Alzheimer disease.

BACKGROUND: The increasing prevalence of Alzheimer disease (AD) and lack of effective agents to attenuate progression have accelerated research and development of disease modifying (DM) therapies. The traditional parallel group design and single time point analysis used in the support of past AD drug approvals address symptomatic benefit over relatively short treatment durations. More recent trials investigating disease modification are by necessity longer in duration and require larger sample sizes. Nevertheless, trial design and analysis remain mostly unchanged and may not be adequate to meet the objective of demonstrating disease modification. Randomized start design (RSD) has been proposed as an option to study DM effects, but its application in AD trials may have been hampered by certain methodological challenges. PURPOSE: To address the methodological issues that have impeded more extensive use of RSD in AD trial and to encourage other researchers to develop novel design and analysis methodologies to better ascertain DM effects for the next generation of AD therapies, we propose a stepwise testing procedure to evaluate potential DM effects of novel AD therapies. METHODS: Alzheimer Disease Assessment Scale-Cognitive Subscale (ADAS-cog) is used for illustration. We propose to test three hypotheses in a stepwise sequence. The three tests pertain to treatment difference at two separate time points and a difference in the rate of change. Estimation is facilitated by the Mixed-effects Model for Repeated Measures approach. The required sample size is estimated using Monte Carlo simulations and by modeling ADAS-cog data from prior longitudinal AD studies. RESULTS: The greatest advantage of the RSD proposed in this article is its ability to critically address the question on a DM effect. The AD trial using the new approach would be longer (12-month placebo period plus 12-month delay-start period; total 24-month duration) and require more subjects (about 1000 subjects per arm for the non-inferiority margin chosen in the illustration). It would also require additional evaluations to estimate the rate of ADAS-cog change toward the end of the trial. LIMITATIONS: A regulatory claim of disease modification for any compound will likely require additional verification of a drug's effect on a validated biomarker of Alzheimer's pathology. CONCLUSIONS: Incorporation of the RSD in AD trials is feasible. With proper trial setup and statistical procedures, this design could support the detection of a disease-modifying effect. In our opinion, a two-phase RSD with a stepwise hypothesis testing procedure could be a reasonable option for future studies.

Defining treatment response to donepezil in Alzheimer's disease: responder analysis of patient-level data from randomized, placebo-controlled studies.

BACKGROUND: Defining treatment success in progressive diseases, such as Alzheimer's disease (AD), can be challenging. OBJECTIVE: To explore the impact of employing different criteria to define a treatment 'responder' using analyses of patient-level data from randomized, placebo-controlled studies of donepezil in AD. METHODS: Trials were included in the analysis if they met several criteria, including the following: randomized, placebo-controlled trial of donepezil 10 mg/day in mild-to-moderate AD; cognition measured by the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) or Mini-Mental State Examination (MMSE); and a 24-week endpoint and outcomes that included global assessments. Definitions of response were: improvements in cognition plus one other domain; improvement in cognition only; improvement or improvement/no change in global response; and improvement/stabilization/less than expected decline by < or = 2 or < or = 4 or < or = 6 points on the ADAS-cog. RESULTS: Five studies identified from the literature search met the specified criteria for inclusion. The response to donepezil measured by ADAS-cog varied from 26% to 63% and that of placebo from 14% to 47%, depending on the definition of improvement used. For definitions that included a less than expected decline on ADAS-cog, the more modest the effect defined, the less the drug versus placebo difference and the higher the percentage of patients meeting this definition. CONCLUSIONS: The definition of treatment 'response' in a progressive neurodegenerative disease can encompass a variety of outcomes, including short-term improvement, longer-term stabilization and a slowed decline in one or more clinically relevant symptoms or symptom domains. The ability to identify groups of people who respond to donepezil underscores the clinical utility of the medication and may contribute to more focused assessments of the cost effectiveness of cholinesterase inhibitors.

Safety of celecoxib compared with placebo and non-selective NSAIDs: cumulative meta-analysis of 89 randomized controlled trials.

OBJECTIVE: Further understand the safety profile of celecoxib and provide safety information for important adverse events (AEs). METHODS: Analysis of randomized controlled trials from the Pfizer clinical trial repository (final study reports completed by 31 July 2011) in which celecoxib was compared with placebo or non-selective non-steroidal anti-inflammatory drugs (nsNSAIDs) for treatment of pain or inflammation in adults. Safety end points comprised 18 terms that had been identified as important AEs among all NSAIDs. RESULTS: There was a greater risk of edema (risk difference (95% confidence interval) 0.77% (0.45, 1.09)); hypertension (0.28% (-0.01, 0.57)); angioedema (0.16% (-0.06, 0.39) and allergic reactions (0.15% (-0.10, 0.40)) with celecoxib than with placebo, while a greater risk of gastrointestinal (GI) hemorrhage (-0.15% (-0.47, 0.16)) was seen with placebo. There was a greater risk of GI hemorrhage (-0.53% (-0.72, -0.33)), GI ulceration (-0.46% (-0.60, -0.33)), edema (-0.62% (-0.89, -0.35)) and hypertension (-0.57% (-0.82, -0.33)) with nsNSAIDs than with celecoxib. CONCLUSIONS: The magnitude of risks associated with NSAIDs is small and similar in celecoxib-, nsNSAID- and placebo-treated patients. This analysis provides safety information that will allow physicians to make informed treatment decisions for patients who are appropriate candidates for celecoxib use.