July 5, 2006 (AIDSmeds)—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.
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