20. Men or women of childbearing potential who are unwilling to practice adequate contraception during the study (adequate contraceptive measures include use of a condom with spermicide and one of the following highly effective methods: stable use of oral contraceptives or other prescription pharmaceutical contraceptive, intrauterine device (IUD); bilateral tubal ligation, vasectomy, additional barrier method [e.g., diaphragm, cap, sponge]).