 - Human immunodeficiency virus HIV-positive patients with well-controlled disease, as determined by CD4 count and viral load, who are on antiretroviral therapy that does not contain a strong inducer or inhibitor of CYP3A4 are allowed on trial; HIV-positive patients on combination antiretroviral therapy with strong inducers or inhibitors of CYP3A4 are ineligible; patients with poorly controlled HIV are not eligible 