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July 5, 2006
New Aptivus Warning: Bleeding in the Brain
by Tim Horn
The U.S. Food and Drug Administration announced on June 30 that it is working with Boehringer Ingelheim, the manufacturer of Aptivus® (tipranavir), to inform healthcare providers about a potentially serious health problem that has been in seen in patients taking the protease inhibitor. Intracrianial hemorrhage (ICH) – bleeding in the brain due to ruptured blood vessels in the head – was seen in a small number of patients who took the protease inhibitor in clinical trials. However, it is not clear what role Aptivus plays in this complication that can cause stroke and death.
In clinical trials, there have been 14 reports of ICH, including eight deaths, among 6,840 study volunteers who took Aptivus. Aptivus, combined with Norvir® (ritonavir), was approved by the FDA in June 2005 for HIV-positive people with drug-resistant virus.
Many of the study volunteers who experienced ICH had other medical conditions known to increase the risk of bleeding in the brain, such as central nervous system lesions, recent neurosurgery, high blood pressure, or alcohol abuse. Some patients were also taking anticoagulants or antiplatelet medications – blood thinners used to treat or prevent blood vessel blockage that are associated with a risk of internal bleeding.
It is not known what role Aptivus plays in the development of ICH. Study volunteers in clinical trials did not appear to have any abnormality associated with poor blood clotting. However, in test tube studies, Aptivus inhibited human platelet aggregation – the clumping of platelets needed to stop excessive bleeding.
The FDA and Boehringer Ingelheim are not recommending that patients undergo tests to measure blood clotting either before or during treatment with Aptivus. However, they are stressing that the drug be used with caution in patients who may have other risk factors for excessive bleeding from trauma, surgery or other medical conditions, or who are receiving medications known to increase the risk of bleeding.
