At present commercially available plasma-derived bovine thrombin (thrombin) is used to improve clotting during surgical procedures and stop bleeding.
Each year, bThrombin is used to treat more than one million patients who undergo surgical procedures in the United States. However, approximately 20 percent of these patients develop antibodies against bovine coagulation factors that can cross-react with human coagulation proteins and possibly lead to adverse effects, including severe bleeding and thrombosis. Due to these safety concerns, rhThrombin was developed as an alternative to bThrombin.
"We constantly look for new ways to reduce risks in surgery and stopping surgical bleeding safely and effectively is of foremost interest to surgeons.
The results from this phase III trial show that we can stop bleeding in 95 percent of patients within 10 minutes and do so without introducing foreign proteins that can carry greater risk of development of antibodies," said William C. Chapman, MD, FACS, Department of Surgery, Washington University, St. Louis (MO) School of Medicine.
"I'm most encouraged by the increasing evidence that recombinant technology is safe and effective because it means that we may be able to avoid using blood or blood products from other people or animals and automatically diminish the risk of infection and the associated immunologic responses that have been noted in the past."
The randomized, double-blind comparative study included 411 patients who underwent surgical procedures at 34 U.S. medical centers across the country. One group of patients (n=206) was treated with bThrombin and a second group (n=205) was treated with rhThrombin, both of which were applied topically to the bleeding site(s) in combination with an absorbable gelatin sponge.
The primary endpoint was the time it took for hemostasis to occur, as measured by the incidence of hemostasis within 10 minutes. Secondary endpoints included the incidence and severity of adverse events and the incidence of antiproduct antibodies.
The study demonstrated that both rhThrombin and bThrombin had comparable efficacy, with 95 percent of patients in each treatment group achieving hemostasis within 10 minutes. The two treatments had similar safety profiles, although antibody development was significantly lower in patients treated with rhThrombin compared with bThrombin (1.5 percent versus 21.5 percent, respectively).