Response assessment:
An interim response assessment was done post completion of induction
phase I (D35) either with PET-CT or by using conventional imaging
techniques. Care was taken to also include the same imaging modality
that was used in initial assessment for ease of comparison. Complete
response (CR) was defined as the absence of all clinical and cytological
evidence of disease with >70% reduction in diameter of all
the lesions assessed by either X-ray/CT/MRI or a complete metabolic
response with Deauville’s score of 1-3 in PET-CT. Partial response (PR)
was defined as Clinico-cytologic response with <70% decrease
in any of the lesion with no new lesions by X-ray/CT/MRI or a PET
positivity with Deauville’s score 4 with a decrease in metabolic
activity compared to baseline scans and Progressive disease (PD) as
clinico-radiologic worsening with Duvellie’s score 5 and/or appearance
of new leisions in interim PET. Patients who had PR in the
post-induction phase I (D35), response assessment were re-assessed at
the end of the induction phase II (D64). Patients who had baseline bone
marrow involvement with >5% blasts underwent reassessment
only by flow-cytometric minimal residual disease (MRD) post-induction
phase I (D35). Post-phase I induction MRD was considered positive when
the levels >0.01%. In CNS-3 patients, CSF analysis was
repeated weekly along with Intra-thecal methotrexate administration
until two consecutive CSF analysis remained negative for blasts.