Abstract: This invention relates to a method of treatment and dosing regimen for treating disease, such as cancer and mammalian tumors, wherein therapy with a cytotoxic drug is suitable, by the administration of an antibody-toxin conjugate, such as a maytansinoid toxin, by infusion at an initial infusion rate of 1 mg/min or lower on a schedule selected from the group consisting of: (1) an amount of at least about 90 mg/m2 on day 1 and day 8, every three weeks; (2) at least an amount of about 30 mg/m2 on day 1, day 2 and day 3, every three weeks; (3) at least an amount of about 45 mg/m2 on day 1, day 8, and day 15, every 4 weeks; and (4) at least an amount of about 45 mg/m2 on day 1, day 8 and day 15, every 3 weeks.