 The first 3 patients will be assigned treatment A. All three patients will be treated and observed for one month. If no DLTs are observed in the first 3 patients, accrual to arm A will be put on hold and accrual will continue with Arm B. However, if 1 DLT is observed in Arm A, up to 3 additional patients will be treated on Arm A, until either 2 DLTs have been observed, or 6 patients have been treated with just 1 DLT among them. If 2 DLTs are observed in Arm A, the study will terminate and all treatments will be deemed intolerable. The same principles apply to the cohorts treated on B-E: if the number of DLTs after one month of treatment is zero, accrual proceeds to the next treatment group; if it is 1, accrual continues with the same treatment for up to 3 additional patients; if it is 2, no patients will be treated on the remaining treatment arms. 