Use of prophylactic methods of birth control throughout the study period for male and female subjects who are not surgically sterile or postmenopausal: abstinence or barrier methods for male subjects, use of additional form of contraception (abstinence, barrier or hormal method) for women of child-bearing potential with a history of tubal ligation, and use of two forms of contraception for women of child-bearing potential who had been enrolled in this study prior to knowledge of the developmental toxicity data in monkeys.