8. In the absence of rapidly progressing disease, the interval from prior treatment to time of study drug administration should be at least 2 weeks for cytotoxic agents, or at least 5 half-lives for noncytotoxic agents. Exceptions are 1) hydroxyurea that requires no washout prior to the start of Hu8F4, and 2) up to 2 doses of single-agent cytarabine (up to 3 grams/m2) given for palliative purposes for which a washout of >/=48 hrs is required