6. Agrees to use a barrier form of contraception if engaging in sexual activity at any time throughout the study (males and females) - two reliable forms of barrier contraception diaphragm, Intra Uterine Device (IUD), spermicides or condoms) must be used if participants engage in sexual activity that could result in pregnancy; hormonal contraception (e.g., oral contraceptive pill, injectable or implantable contraceptive) must not be relied upon while in this study; all female participants must be willing to undergo urine pregnancy tests at time points indicated in the Schedule of Events and Procedures