- Interval therapy for VLR, AR1, or AR2 patients (begins 14 days after completion of protocol I): Patients receive oral MP daily on days 1-56; HD-MTX IV over 24 hours on days 8, 22, 36, and 50; leucovorin calcium (CF) (or levofolinic acid) orally or IV beginning 36 hours after initiation of MTX infusion and repeating every 6 hours until hour 72 or until serum MTX level is adequate; and TIT on days 9, 23, 37, and 51.