- Length of time required for abstinence or use of contraceptives should take into account the reproductive toxicity profile including genotoxicity and teratogenicity, the size of the molecule, and the number of doses. Male subjects must agree to use contraception during the treatment period and for at least 2 days after the last dose of study treatment and refrain from donating sperm during this period. Only female subjects of WONCBP are eligible to participate.