The observation of gastrointestinal intolerability and the emergence of resistant virus led to the cessation of development activities in favor of compounds with improved antiviral profiles.
An Fc-aglycosylated, non–T-cell–depleting and CD4-specific humanized IgG1 derived from the parent murine B4, which binds to discontinuous, conformational epitopes on the HIV-receptor complex, including CD4 domain 1, and competitively blocks HIV entry
Tipranavir (TPV) is a non-peptidic HIV-1 protease inhibitor that inhibits the virus-specific processing of the viral Gag and Gag-Pol polyproteins in HIV-1 infected cells, thus preventing formation of mature virions.
The in vitro results showed that the EC50 of BILR 355 was 0.26 ng/ml (0.59 nM) against wild-type HIV-1 and ranged from 1.5 to 13 ng/ml (3.4 –29 nM) against clinically common single and double NNRTI mutations .
