FDA advisers will meet to recommend approval of Aptivus

Boehringer Ingelheim's experimental HIV protease inhibitor is effective in some drug-resistant patients when used in combination with Abbott Laboratories' Norvir, U.S. regulatory staff said in documents released Wednesday. Studies showed the Boehringer protease inhibitor, called Aptivus (tipranavir), helped heavily treated patients more than other antiretroviral drugs on the market, Food and Drug Administration reviewers said. FDA staffers said their analysis of the drug's safety and effectiveness was consistent with the company's findings. Germany's Boehringer, the world's largest privately held drug company, is seeking approval to treat HIV patients who have had the virus for a period of time and have already taken other drugs. Documents were released ahead of an FDA meeting of outside experts Thursday to discuss whether to recommend that the agency approve the drug. The agency usually follows the advice of its panelists. Two major clinical trials for Aptivus "provide evidence of the additional antiviral effect over currently available antiretroviral regimens in a population which are 'heavily pre-treated,' " the agency reviewers said. Although there are already eight protease inhibitors approved for the U.S. market, most patients develop resistance. Health experts have called for new drugs that are different enough from the old ones to give patients more options. In one Boehringer analysis, 39% of patients taking Aptivus in combination with a low dose of Abbott's Norvir showed lower virus level after 24 weeks, compared with 21.4% of those taking another Abbott drug, Kaletra. Another company analysis showed 13.1% of those taking Aptivus and Norvir showed improvement compared with 9.1% of patients taking other protease inhibitors with Norvir, Boehringer has said. FDA staff raised some safety concerns. While most patients were in late stages of the disease, the reviewers said they could not rule out Aptivus's role in the deaths of 102 patients during development of the drug. "This unclear ascertainment of study drug's relationship to mortality (and to morbidity) is due to the nature of the population under study, and in many cases, was due to the lack of available information surrounding the death cases," the FDA staff wrote. They also said they were concerned about the drug's impact on the liver and lipids and about a higher risk of rash in women. A spokeswoman for the company did not immediately return a call seeking comment on the documents. (Reuters)