15. Women of child-bearing potential must use two methods of acceptable contraception including one highly effective method and a barrier method, as directed by their physician, during treatment and for at least 24 months after completion of study treatment. Highly effective methods of contraception are defined as those which result in a low failure rate (i.e., less than 1% per year) when used consistently and correctly (e.g., implants, injectables, combined oral contraception, or intra-uterine devices). At the discretion of the Investigator, acceptable methods of contraception may include total abstinence. Periodic abstinence (e.g., calendar, ovulation, symptothermal, and post ovulation methods) and withdrawal are not acceptable methods of contraception (See Appendix B).