18. Females of childbearing potential if they are not using proper contraception (hormonal contraception, intrauterine device [IUD] or surgical sterilization, spermicidal foam in conjunction with condom on male partner) during the study. Use of oral/hormonal contraception alone is not acceptable. (Note: women of childbearing potential with no current heterosexual relationship can be included without contraception according to the judgement of the investigator).