- Part I: Patients receive oral MP once daily on days 1-14; high-dose (HD) MTX IV over 24 hours on days 1 and 8; leucovorin calcium orally or IV at 42, 48, and 54 hours after each dose of MTX until MTX plasma levels are safe; and MTX IT on days 2 and 9. Patients also receive PRDL or therapeutic HC IT on days 2 and 9.