Contributions
Type: Oral Presentation
Presentation during EHA20: From 13.06.2015 12:00 to 13.06.2015 12:15
Location: Room C1
Background
Early response to induction chemotherapy has been demonstrated to be one of if not the most significant prognostic factors in the outcome of children with acute lymphoblastic leukemia. Multiparametric flow cytometry (mpFC) has been the routinely used methodology in the US for the determination of this response. New high throughput sequencing (HTS) technologies of rearranged immune receptor (TCR and Ig) genes have raised the possibility of a more accurate, sensitive, and standardizable approach to determination of early response to therapy in ALL patients.
Aims
In this study, we investigated whether the Adaptive Biotechnologies immunoSEQ assay of IgH (immunoglobulin heavy chain (VDJ/DJ) and TCRG (T-cell receptor gamma) would be able to quantify residual disease at the end of induction therapy for children with ALL and be of prognostic value with regard to outcome (relapse free survival and overall survival) in these patients.
Methods
This study involved a total of 432 patients enrolled on COG clinical trials AALL0331 and AALL0232 for whom mpFC measurement of residual disease was <0.1% and for whom outcome data are available.
MpFC was performed at the University of Washington and Johns Hopkins as part of the evaluation for MRD. Genomic DNA was extracted from frozen bone marrow specimens collected at diagnosis and at day 29 post the start of induction therapy. High throughput sequencing of CDR3 regions of IGH and TCRG was performed on all samples. Diagnostic and d29 matched samples from a given patient were sequenced and dominant (>5%) clonal CDR3 sequences from diagnosis were searched for in the corresponding d29 sample. An exact 100 base pair match was required for identification of the sequence as residual disease in the follow-up sample. Both the presence and the frequency of the MRD clone relative to the total IGH repertoire and total nucleated cell population were determined.
Results
The assays defined the dominant clonal sequences in >90% of the patients. Approximately 60% of this subgroup was found to have residual disease present at d29. Clones from some of the patients demonstrated a single “trackable” sequence while clones from other patients demonstrated multiple trackable sequences either within or between the two immune receptor loci being assessed. Approximately, 50 % of the residual disease detected by HTS was beneath the level of sensitivity of mpFC and therefore previously read out as MRD negative. Correlations between mpFC and HTS and independent correlations of each of these two methodologies with outcome will be presented.
Summary
This is the largest patient cohort studied to date for which mpFC, HTS, and outcome data are all available. This study allows an informative assessment of the capability of HTS to determine early response to induction chemotherapy and the relevance of that determination to patient outcome.
Keyword(s): B cell acute lymphoblastic leukemia, IgH rearrangment, Minimal residual disease (MRD)
Session topic: Translational studies in ALL
Type: Oral Presentation
Presentation during EHA20: From 13.06.2015 12:00 to 13.06.2015 12:15
Location: Room C1
Background
Early response to induction chemotherapy has been demonstrated to be one of if not the most significant prognostic factors in the outcome of children with acute lymphoblastic leukemia. Multiparametric flow cytometry (mpFC) has been the routinely used methodology in the US for the determination of this response. New high throughput sequencing (HTS) technologies of rearranged immune receptor (TCR and Ig) genes have raised the possibility of a more accurate, sensitive, and standardizable approach to determination of early response to therapy in ALL patients.
Aims
In this study, we investigated whether the Adaptive Biotechnologies immunoSEQ assay of IgH (immunoglobulin heavy chain (VDJ/DJ) and TCRG (T-cell receptor gamma) would be able to quantify residual disease at the end of induction therapy for children with ALL and be of prognostic value with regard to outcome (relapse free survival and overall survival) in these patients.
Methods
This study involved a total of 432 patients enrolled on COG clinical trials AALL0331 and AALL0232 for whom mpFC measurement of residual disease was <0.1% and for whom outcome data are available.
MpFC was performed at the University of Washington and Johns Hopkins as part of the evaluation for MRD. Genomic DNA was extracted from frozen bone marrow specimens collected at diagnosis and at day 29 post the start of induction therapy. High throughput sequencing of CDR3 regions of IGH and TCRG was performed on all samples. Diagnostic and d29 matched samples from a given patient were sequenced and dominant (>5%) clonal CDR3 sequences from diagnosis were searched for in the corresponding d29 sample. An exact 100 base pair match was required for identification of the sequence as residual disease in the follow-up sample. Both the presence and the frequency of the MRD clone relative to the total IGH repertoire and total nucleated cell population were determined.
Results
The assays defined the dominant clonal sequences in >90% of the patients. Approximately 60% of this subgroup was found to have residual disease present at d29. Clones from some of the patients demonstrated a single “trackable” sequence while clones from other patients demonstrated multiple trackable sequences either within or between the two immune receptor loci being assessed. Approximately, 50 % of the residual disease detected by HTS was beneath the level of sensitivity of mpFC and therefore previously read out as MRD negative. Correlations between mpFC and HTS and independent correlations of each of these two methodologies with outcome will be presented.
Summary
This is the largest patient cohort studied to date for which mpFC, HTS, and outcome data are all available. This study allows an informative assessment of the capability of HTS to determine early response to induction chemotherapy and the relevance of that determination to patient outcome.
Keyword(s): B cell acute lymphoblastic leukemia, IgH rearrangment, Minimal residual disease (MRD)
Session topic: Translational studies in ALL