Experimental clot inhibitors match conventional drugs

From Orlando, Fla., at a meeting of the American Society of Hematology

Two new drugs—one in pill form and another requiring only a single weekly injection—prevent dangerous blood clots in leg veins just as well as do standard treatments that require daily shots, two European research teams report.

In one study, scientists in Sweden focused on people who were undergoing knee-replacement surgery, a group at high risk of developing clots. The researchers gave 1,029 of the patients an experimental oral drug called dabigatran etexilate a few hours after surgery and then daily for at least a week. Another group of 512 patients received a standard treatment, enoxaparin (Lovenox)—a derivative of the blood thinner heparin—by daily injection for a week, starting 12 hours before surgery.

Slightly more than one-third of the patients in each group developed a severe leg clot called deep-vein thrombosis during the 8 days after surgery, reports physician Bengt I. Eriksson of the University Hospital Sahlgrenska/Östra in Gothenburg. Knee-replacement patients who don’t get an anticoagulant face a 60 to 80 percent chance of developing such a clot.

“This is a new anticoagulant that provides safe and reliable protection, with convenience,” Eriksson says.

In another study, researchers in the Netherlands identified 2,904 people who had already experienced deep-vein thrombosis. These patients risk a recurrence even if they’ve received treatment to dissolve the clot and have taken anticoagulant drugs for weeks or months.

The researchers randomly assigned half the patients to receive a single weekly injection of a new drug called idaparinux. The others got a standard treatment that included heparin shots at least five times a week and a drug that suppresses vitamin K.

The regimens worked equally well. Six months after their initial clots were diagnosed, only 3 percent of patients in either group had clots return. Anticoagulants can hike abnormal bleeding, and 8 percent of each group reported bleeding.

Indaparinux may ease the burden of treatment, says study coauthor Harry R. Büller, a physician at the Academic Medical Center in Amsterdam.