A study presented at the American College of Cardiology meetings in Chicago last week confirmed that a new anticoagulant drug - ximelagatran (Exanta®, AstraZeneca) - was as effective as coumadin in preventing stroke in patients with atrial fibrillation.
Stroke is the most feared side effect in patients with atrial fibrillation, occurring in up to 35% of patients who have this arrhythmia. Previous studies have shown that taking sufficient doses of coumadin can significantly reduce the risk of stroke. Unfortunately, coumadin - a "blood thinner" that reduces the blood's ability to clot - is a difficult drug to administer. Its appropriate use requires frequent blood tests and dosage adjustments, a practice that both doctors and patients find impractical. If not regulated carefully, however, problems can result. If not enough coumadin is given, the risk of stroke is not reduced. If too much coumadin is given, severe bleeding can result - including brain hemorrhage. Unfortunately, because of the difficulty in administering the drug properly, studies have documented that only about half the patients who should be getting coumadin are receiving it appropriately.
Ximelagatran is the first of a new class of drugs being developed as a replacement for coumadin. Its major advantage is that it can be given as a standard dose, without the need of blood tests and constant dosage adjustment.
In the study reported at the ACC meetings last week, over 3000 patients with atrial fibrillation were randomized to receive either ximelagatran or coumadin. The dosage of coumadin was monitored frequently to be sure it was in the "therapeutic range," whereas ximelagatran was administered in a standard, twice-per-day dosage with no monitoring. After an average follow-up period of 17 months, patients randomized to ximelagatran did at least as well as patients randomized to coumadin - and investigators may have seen a trend toward even fewer strokes and fewer bleeding complications with the new medication. Once generally available, ximelagatran - or other new drugs in the same class - may revolutionize the management of atrial fibrillation and other disorders caused by excessive blood clotting. However, more studies are required to document the safety and effectiveness of this new agent before it can be submitted to the FDA for approval. That submission may occur later this year, and release of ximelagatran may occur as early as 2004.