DIAMOND-MI Supports Dofetilide Benefit

Pfizer's new class III antiarrhythmic drug dofetilide has been shown toreduce arrhythmic events in patients who have suffered a myocardial infarction, according to the results of the DIAMOND-MI study. This is the second large-scale Phase III study to support dofetilide's efficacy; the first, in patients with congestive heart failure (DIAMOND-CHF), was reported earlier this year at the European Society of Cardiology meeting (Marketletter September 22).

There is a pressing need for new drugs to treat patients in these settings. Despite great advances in medical treatment for heart attack in recent years, patients still have a very high mortality, and those who also end up with depressed left ventricular function often go on to develop heart failure and arrhythmias.

The DIAMOND-MI trial enrolled 1,510 post-MI patients (out of a total of 8,000 screened), who were selected on the basis of severely depressed left ventricular function using echocardiography. Two to seven days after symptom-onset, the patients were randomized to receive either dofetilide, a selective potassium channel blocker, or placebo. This was a study of patients who had survived a severe MI; two-thirds of those enrolled were already showing signs of CHF, and 8% had atrial fibrillation at enrollment. The patients included 25% women and a significant number of patients with co-morbidities such as diabetes and hypertension.