- Protocol IB therapy (beginning on day 36 of induction therapy): Patients receive cyclophosphamide (CPM) IV over 1 hour on days 1 and 29 and oral mercaptopurine (MP) on days 1-28; ARA-C IV on days 3-6, 10-13, 17-20, and 24-27; ARA-C IT on day 10; and MTX IT on day 24. Patients also receive PRDL or therapeutic HC IT on days 10 and 24.