- Patient must not be pregnant or nursing because bevacizumab or erlotinib maybe harmful to the developing fetus and newborn. Women of reproductive potential must have a negative serum pregnancy test within 7 days prior to study consent. Post-menopausal women must be amenorrheic for at least 12 months to be considered of non-childbearing potential. Patients of reproductive potential must agree to employ an effective barrier method of birth control throughout the study and for up to 3 months following discontinuation of study drug.