Clinical course of classic Kaposi's sarcoma in HIV-negative patients treated with the HIV protease inhibitor indinavir.

HIV protease inhibitors have been shown to exert antiangiogenic and antitumor actions independently from their antiretroviral effect. Based on these studies, HIV-seronegative patients with classic Kaposi's sarcoma were treated with indinavir and followed for clinical evolution, drug pharmacokinetics and Kaposi's sarcoma biomarkers. A favorable clinical course was associated with high drug plasma levels, reduced production of basic fibroblast growth factor, lower numbers of circulating endothelial cells, and a decrease in antibody titers against human herpesvirus 8.