Patients
From November 1, 2004 to January 7, 2011, COG AALL02P2 enrolled patients
18 months to <30 years old at the time of relapse with B-or
T-ALL and first iCNS-R or testicular relapse occurring ≥18 months from
the date of initial diagnosis. Only patients with <5% marrow
blasts by morphology assessed locally were eligible. Children with Down
syndrome were excluded, as were those who underwent bone marrow
transplant in first remission. Patients with known optic nerve and or
retinal involvement were not eligible because they could not delay
radiotherapy for 12 months.
COG AALL02P2 included modifications to the POG 9412 backbone aimed at
providing intensified systemic therapy for 12 months prior to radiation
to address the issue of marrow relapse, as well as optimize use of drugs
known to better target the CNS compartment including dexamethasone, with
HD cytarabine and methotrexate (dose increased from 1 to 5
g/m2 per cycle), plus 1200 cGy CRT. Additionally,
pegaspargase was given (POG 9412 used native E. coli asparaginase). A
secondary objective was to determine if the frequency of bone marrow
involvement via flow-cytomery at the time of extramedullary relapse, and
to assess if the level of pre-treatment minimal residual disease (MRD)
correlated with outcomes.