Research in the Robert Siliciano Laboratory focuses on HIV and antiretroviral therapy (ART). ART consists of combinations of three drugs that inhibit specific steps in the virus life cycle. Though linked to reduced morbidity and mortality rates, ART is not curative. Through our research related to latently infected cells, we've shown that eradicating HIV-1 infection with ART alone is impossible due to the latent reservoir for HIV-1 in resting CD4+ T cells. Our laboratory characterized the different forms of HIV-1 that persist in patients on ART. Currently, we are searching for and evaluating drugs that target the latent reservoir. We are also developing assays that can be used to monitor the elimination of this reservoir. We are also interested in the basic pharmacodynamic principles that explain how antiretroviral drugs work. We have recently discovered why certain classes of antiretroviral drugs are so effective at inhibiting viral replication. We are using this discovery along with experimental and computational approaches to develop improved therapies for HIV-1 infection and to understand and prevent drug resistance. Finally, we are studying the immunology of HIV-1 infection, and in particular, the ability of some patients to control the infection without ART.

Research in the Craig W. Hendrix Lab concentrates on the chemoprevention of HIV infection, clinical pharmacology of antiviral drugs, drug interactions, and oral, topical and injectable HIV microbicide development. Our lab conducts small, intensive sampling studies of PK and PD of drugs for HIV prevention with a focus on developing methods to better understand HIV and drug distribution in the male genital tract, female genital tract and lower gastrointestinal tract. We also support numerous HIV pre-exposure prophylaxis development studies from phase I to phase III, largely as leader of the Pharmacology Core Laboratory of both the Microbicide Trial Network and HIV Prevention Trials Network.

A. Laboratory activities include the use of accelerator mass spectrometry (AMS) techniques to measure intracellular drugs and drugs metabolites. AMS is a highly sensitive method for detecting tracer amounts of radio-labeled molecules in cells, tissues, and body fluids. We have been able to measure intracellular zidovudine triphosphate (the active anabolite of zidovudine) in peripheral blood mononuclear cells from healthy volunteers given small doses of 14C-zidovudine, and have directly compared the sensitivity of AMS to traditional LC/MS methods carried out in our laboratory. B. Clinical research activities investigate the clinical pharmacology of new anti-HIV therapies and drug combinations. Specific drug classes studied include HIV reverse transcriptase inhibitors, protease inhibitors, entry inhibitors (selective CCR5 and CXCR4 antagonists), and integrase inhibitors. Scientific objectives of clinical studies include characterization of early drug activity, toxicity, and pharmacokinetics. Additional objectives are characterization of pathways of drug metabolism, and identification of clinically significant harmful and beneficial drug interactions mediated by hepatic and intestinal cytochrome P450 isoforms.