Ritonavir and Agenerase Treatment for Patients Who Have Failed Previous Anti-HIV Treatment

Inclusion Criteria Patients may be eligible for this study if they: Are 18 years of age or older. Are HIV-positive. Have a viral load (level of HIV in the body) of more than 1,000 copies/ml. Have had more than 12 weeks of prior anti-HIV drug treatment. Have failed a previous anti-HIV treatment containing nelfinavir as the only protease inhibitor. Are responsive to Agenerase. Are able to follow study requirements. Exclusion Criteria Patients will not be eligible for this study if they: Are intolerant to ritonavir (an anti-HIV drug). Have or have had problems with absorption. Have liver disease or damage. Have pancreatic disease or damage. Have taken any protease inhibitor other than nelfinavir. Are receiving investigational drugs or devices from another study. Are pregnant or breast-feeding. Currently use triazolam, astemizole, ergot medications, cisapride, midazolam, bepridil, rifampin, terfenadine, or pimozide. Have a bleeding disorder. Have previously been treated with Agenerase. Are receiving nonnucleosides.