- Histologically confirmed Acute Lymphoblastic Leukemia or Acute Lymphoblastic Lymphoma (ALL) in patients in first remission at the start of Interim Maintenance I. HDMTX is administered during the phase of chemotherapy referred to as "Interim Maintenance I". Interim maintenance I occurs after induction and consolidation, is approximately 64 days in duration, and involves administration of four doses of HDMTX, with a dose given approximately every two weeks.