Initial Treatment for B-Cell Acute Lymphoblastic Leukemia in a 1-Year-Old

Induction Therapy

The National Comprehensive Cancer Network recommends a 4-drug induction regimen consisting of a corticosteroid, vincristine, an anthracycline, and pegaspargase for pediatric B-ALL patients, including a 1-year-old, followed by CNS prophylaxis with intrathecal chemotherapy, consolidation therapy, and prolonged maintenance treatment 1, 2, 3
For a 1-year-old patient, prednisone is preferred over dexamethasone to minimize toxicity risk, particularly osteonecrosis, though dexamethasone provides better CNS penetration 1, 2
Vincristine should be administered at 1.4 mg/m² IV (maximum 2 mg) weekly during induction 1, 2
An anthracycline, such as daunorubicin, should be administered at 25-30 mg/m² IV weekly 1, 2, 4
L-asparaginase, in the form of pegaspargase, should be administered at 2,500 IU/m² IV (doses vary by protocol, typically 1-3 doses during induction) 1, 2

CNS-directed therapy must begin during induction and continue throughout treatment, including intrathecal chemotherapy with methotrexate, cytarabine, and dexamethasone (triple intrathecal therapy) 5, 3
Systemic high-dose methotrexate should be incorporated during consolidation phases 5, 1

After achieving complete remission, consolidation therapy includes high-dose methotrexate, cyclophosphamide, cytarabine, and mercaptopurine in various combinations 1, 2
Additional pegaspargase doses should be administered during consolidation 1, 2
Continued intrathecal chemotherapy is necessary during consolidation 3

MRD assessment at end of induction is the most critical prognostic factor, with MRD ≥0.01% requiring intensified therapy and MRD <0.01% following standard consolidation and maintenance 1, 2, 3
Infant-specific considerations, such as higher incidence of KMT2A rearrangements and potential need for dose modifications, should be taken into account for patients under 1 year of age 3

Standard maintenance therapy continues for approximately 2-3 years total from diagnosis and includes daily oral mercaptopurine, weekly oral methotrexate, monthly vincristine pulses, and pulse dexamethasone 1, 6

Treatment should be administered at a specialized pediatric cancer center with expertise in ALL management given the complexity of therapy and need for supportive care 7