Have full understanding of all elements of, and signature and dating of the written informed consent prior to the initiation of protocol specified procedures. Females with childbearing potential must have a negative pregnancy test before and during the study period. Sexually active females must be using an effective form of birth control. These methods include oral contraceptives ("the pill"), an intrauterine device (IUD), levonogestrol implants (Norplant®), medroxyprogesterone acetate injections (Depo-provera®) or contraceptive foam with a condom.