- Patients must have a lumbar puncture to determine CNS involvement of ALL within 14 days prior to registration; patients with CNS3 are excluded from the trial; patients with CNS1 or CNS2 will be eligible, but will be monitored for CNS involvement; note that intrathecal methotrexate administered during the pre-study lumbar puncture may count as the first dose of intrathecal therapy required as part of the study