- Child-bearing potential, has a negative serum pregnancy test at baseline, and agrees to one of the following methods for avoidance of pregnancy during the period of the study and until 30 days after last dose of study medication: Oral contraceptive, either combined or progestogen alone, Injectable progestogen, Implants of levonorgestrel, Oestrogenic vaginal ring, Percutaneous contraceptive patches., Intrauterine device (IUD) or intrauterine system (IUS) showing that the expected failure rate is less than 1% per year as stated in the IUD or IUS product label, Has a male partner who is sterilised, Double barrier method: condom and an occlusive cap (diaphragm or cervical/vault caps) with a vaginal spermicidal agent (foam/gel/film /cream/suppository).