15. Women of childbearing potential (WOCBP) must have a negative serum pregnancy test within 7 days of the first administration of study treatment and must be willing to use two methods of contraception one of them being a barrier method or abstain from sexual activity during the study and for 3 months after last study drug administration. Sexually active males and their female partners must agree to use two methods of accepted and effective method of contraception (hormonal or barrier methods, abstinence) prior to study entry and for the duration of the study.