12. Female patients of childbearing potential must have a negative serum pregnancy test. Sexually active patients must be willing to use non-hormonal contraception, including condom use by male partner, and barrier method by the female partner during the treatment period and for at least 3 months after the last dose of the study drug. Females considered not of childbearing potential include those who have been in menopause > 2 years, or are surgically sterile (status post tubal ligation or hysterectomy).