Recombinant Activated Factor VII May Increase Clot Risk
Large literature review finds association with arterial, but not venous, thromboembolic events
WEDNESDAY, Nov. 3 (HealthDay News) -- Use of recombinant activated factor VII (rFVIIa) to treat bleeding may increase the risk of arterial -- though not venous -- thromboembolic events, particularly in the elderly, according to research published in the Nov. 4 issue of the New England Journal of Medicine.
Marcel Levi, M.D., of the University of Amsterdam in the Netherlands, and colleagues analyzed data from a literature review of 35 placebo-controlled, randomized clinical trials involving 4,468 patients to assess the thromboembolic risk associated with the use of rFVIIa.
The researchers found that 498 (11.1 percent) of the subjects had thromboembolic events. Rates of arterial thromboembolic events were higher among those who received rFVIIa than those who got placebos (5.5 versus 3.2 percent), particularly in patients 65 or older (9.0 versus 3.8 percent). In those aged 75 or older, the rate was especially high (10.8 versus 4.1 percent). However, venous thromboembolic events occurred at a similar rate among rFVIIa and placebo recipients (5.3 versus 5.7 percent).
"The data presented provide a systematic evaluation of rates of thromboembolic events in placebo-controlled trials of rFVIIa. It is important to note that central nervous system bleeding occurs in an older population with an inherently increased risk of thromboembolic events. Therefore, risk-benefit considerations should be evaluated before administering any hemostatic agent," the authors write.
The study was funded by Novo Nordisk; three authors disclosed financial relationships with the company, including employment.