Anti-clot medicine shows potential

Pill more effective than shot in post-surgery patients

By Jill Coley

The Post and Courier

Monday, July 7, 2008

The anti-clotting drug rivaroxaban might be the first new oral agent for blood thinners in 60 years, Dr. Richard J. Friedman, a Roper St. Francis orthopedic surgeon, said.

Friedman participated in one of the international trials sponsored by Bayer, which plans to market the drug as Xarelto.

In trials, the pill was more effective at reducing the rate of blood clots following hip and knee replacement surgeries than the current standard of treatment, low-molecular heparin. The pill is easier to take than the injectable low-molecular heparin. Both drugs had a similar risk of major bleeding.

West Ashley resident Wendy Williams, 56, had terrible hip pain while walking because of a congenital condition in which the ball never sat properly in the socket, she said. She had one hip replaced in 2006 and the other in 2007.

She participated in the drug trial for both surgeries. All patients took pills and gave themselves shots, since neither the doctor nor the patient knew which drug was administered.

"The pills were much, much easier than getting shots in the stomach," Williams said.

More than 700,000 hip and knee replacement surgeries are performed annually in the U.S., and that number will continue to grow as baby boomers age, Friedman said.

The international research effort comprised four studies examining the drug's effectiveness in reducing blood clots in total knee and total hip replacement patients. Two of those studieshave appeared in The New England Journal of Medicine and one in The Lancet, an independent medical journal published in the United Kingdom. The fourth was presented in May at an annual orthopedic meeting in France.

In the hip surgery trial, 1.1 percent of patients given rivaroxaban suffered deep-vein blockage or pulmonary embolism. Those who received low-molecular heparin, experienced clots at a rate of 3.7 percent. The knee surgery trial showed a 50 percent reduction in the rate of clots when compared with low-molecular heparin.

Rivaroxaban might be useful to people who take anti-coagulants for other conditions.

"A lot of people take Coumadin for heart valves, strokes and atrial fibrillation," Friedman said.

Coumadin, also known as warfarin, is a difficult pill to work with because patients' blood must be monitored constantly to make sure the dose remains therapeutic, he said. Constantly changing the dosage can be confusing for elderly patients. Also, since Coumadin operates through vitamin K, diet can affect its performance. Rivaroxaban has no known food interactions.

The pill will be submitted to the Food and Drug Administration for approval, which could take six months to a year, Friedman said. A similar drug is marketed in Europe by a different pharmaceutical company.

Friedman received grant money from Bayer to conduct the trial and also served as a consultant, for which he received an honorarium.