Washington Editor

Boehringer Ingelheim said it launched a Phase III clinical program for tipranavir, the first non-peptidic protease inhibitor in development for the treatment of HIV.

With success in Phase III, the company believes it could launch tipranavir for use in combination therapy at the end of 2004 or in early 2005. Tipranavir would be Boehringer Ingelheim's (BI) second antiretroviral following Viramune (nevirapine), a non-nucleoside reverse transcriptase inhibitor launched in 1997.

But tipranavir could offer something new to the HIV market, Julia Kleinmann, public relations manager for external communications at Boehringer Ingelheim International GmbH, in Ingelheim, Germany, told BioWorld Today.

"Tipranavir belongs to the protease inhibitors, but it's the first non-peptidic protease inhibitor, which is important because the binding properties of the molecule to its access side are more flexible than others," she said. "This flexible binding enables the molecule to even survive mutations so that it can be used for multiple-treatment-experienced patients who have shown some kind of resistance to drugs being applied earlier. So, patients in need of a new treatment could very much benefit from tipranavir."

At the XIV International AIDS Conference held last summer in Barcelona, Spain, BI said its Phase II study of tipranavir demonstrated a significant reduction in HIV-1 levels in patients who had previously had treatment with multiple protease inhibitor-based regimens.

The Phase III program consists of a number of trials, including RESIST 1 & 2, as well as smaller studies designed to evaluate triple class-experienced patients at more than 280 sites worldwide.

In a prepared statement, the company described the Phase III RESIST (Randomized Evaluation of Strategic Intervention in Multi-Drug Resistant Patients with Tipranavir) clinical trial program as study of tipranavir (boosted with low-dose ritonavir) vs. a low-dose ritonavir-boosted comparator protease inhibitor.

RESIST 1 will enroll upward of 500 patients at more than 115 sites in the U.S., Canada and Australia. A baseline test for each participant will determine the best product to combine with tipranavir. RESIST 2 will enroll more than 800 patients in Europe and South America.