NEW YORK (Reuters Health) – A fibrin-derived peptide (FX06) appears to limit infarct size when given during percutaneous coronary intervention (PCI) for acute ST-segment elevation myocardial infarction, according to an expedited publication by the Journal of the American College of Cardiology.

FX06 is believed to improve capillary flow in the heart by reducing leukocyte migration, inflammation, vascular leak and edema, lead author Dr. Dan Atar at the University of Oslo, Norway, and associates explain in their article, posted online on January 28. In animal models of coronary ischemia/reperfusion, FX06 reduced infarct sizes by mitigating reperfusion injury, and phase I trial results demonstrated its safety in humans.

The current phase II, randomized, placebo-controlled trial included 227 patients with a first ST-elevated MI from a single culprit lesion who underwent primary PCI.

In the 110 patients assigned to FX06, the drug was administered in two IV bolus injections of 200 mg each, immediately before and 10 minutes after the guidewire passed the occlusion. Infarct size was measured at 5 days and 4 months after PCI using late gadolinium enhanced cardiac magnetic resonance imaging.

On day 5, the mass and size of the necrotic core zone were reduced by more than half (-58% and -51%, p < 0.025 for both) in the FX06 group compared with the placebo group, Dr. Atar's team reports, "suggesting that FX06 tends to reduce at least one, and perhaps the most important, measure of infarct size."

Although other measures — infarct border zone, microvascular obstruction, and troponin I level — did not differ significantly, “they all showed a numerically consistent trend in favor of FX06.” Furthermore, “the incidences of cardiac death, all serious adverse cardiac events, and new-onset heart failure were all in favor of the FX06 treatment.”

However, scar size at 4 months did not differ between groups.

In an accompanying editorial, Dr. Katherine C. Wu, from Johns Hopkins Medical Institutions in Baltimore, cautions that “an agent should demonstrate sustained, long-term infarct size reduction to be a plausible therapeutic candidate.”

She suggests that FX06 may represent “just another disappointing example in a long list of failed adjunctive therapies for reperfused MI.”

Reference:
J Am Coll Cardiol 2009;53.