9. Subject agrees to use a double barrier method of contraception during the course of study therapy and for at least 3 months after completion of therapy. A double barrier method involves the use of a condom in combination one of the following: sponge, diaphragm, cervical ring with spermicidal gel or foam. Subjects who have had a vasectomy ≥6 months prior to trial therapy and those with female sexual partners who are 55 years old and post-menopausal for 2 years or sterile (by tubectomy, hysterectomy, bilateral oophorectomy) need to agree to use at least a condom.