- Women of child bearing potential (WOCBP) must have a negative serum or urine pregnancy test (minimum sensitivity 25 IU/L or equivalent units of HCG within 72 hours prior to initiation of treatment. This is because DNA alkylating agents are known to be teratogenic, and the effects of irinotecan, OXAL, 5-FU and C225 on a developing fetus at the recommended therapeutic doses are unknown.