A Phase II Study of Dasatinib in Children and Adolescents With Newly Diagnosed Chronic Phase Chronic Myelogenous Leukemia (CML) or With Ph+ Leukemias Resistant or Intolerant to Imatinib

Major Cytogenetic Response (MCyR) rate is defined as the proportion of all treated participants who achieved a complete (0%) or partial (1%-35% Ph+ metaphases in at least 20 metaphases in bone marrow) cytogenetic response, expressed as percentage. The denominator of the MCyR response rate consists of all treated participants in Cohort 1, and the numerator is all participants in Cohort 1 achieving MCyR. 95% confidence interval was calculated by Clopper-Pearson exact method.

Complete Hematologic Response (CHR) rate is defined as the proportion of all treated participants who achieve a confirmed CHR while on-study, expressed as percentage. CHR is defined as including no more than 5% blasts in bone marrow and normal white blood cell count without blasts in peripheral blood, expressed as percentage. The denominator of the CHR response rate consists of all treated participants in Cohort 2, and the numerator is all participants in Cohort 2 achieving CHR. 95% confidence interval was calculated by Clopper-Pearson exact method.

Complete Cytogenetic Response (CCyR) rate is defined as the proportion of all treated participants who achieve a CCyR while on-study, expressed as a percentage. CCyR rate is defined as 0% Ph+ metaphases in at least 20 metaphases in bone marrow. The denominator of the CCyR response rate consists of all treated participants in Cohort 3, and the numerator is all participants in Cohort 3 achieving CCyR. 95% confidence interval was calculated by Clopper-Pearson exact method.

Major Cytogenetic Response (MCyR) rate was defined as the proportion of all treated participants who achieved a complete (0%) or partial (1%-35% Ph+ metaphases in at least 20 metaphases in bone marrow) cytogenetic response. The percentage of treated participants in each arm with MCyR is reported.

Complete Hematologic Response (CHR) rate defined as the proportion of all treated participants who achieve a confirmed CHR while on-study. CHR is defined as including no more than 5% blasts in bone marrow and normal white blood cell count without blasts in peripheral blood. The percentage of treated participants in each arm with CHR is reported.

The number of participants achieving their best on-study cytogenetic response was reported as a percentage of all treated participants in that arm. (Based on >=20 Metaphases)

Time to MCyR is defined as the time from first dose of dasatinib until the first day MCyR criteria are met, computed only for participants whose best response is MCyR. (Based on >=20 Metaphases)

Duration of MCyR will be computed from the first day criteria are met for MCyR until the date progressive disease (PD) is reported (or treatment is discontinued for PD) or death. Participants who neither discontinue due to PD nor die will be censored on the date of their last hematologic or cytogenetic assessment, whichever comes last. (Based on >=20 Metaphases)

Time to CCyR is defined as the time from first dose of dasatinib until the first day CCyR criteria are met, computed only for participants whose best response is CCyR. (Based on >=20 Metaphases)

Duration of CCyR will be computed from the first day criteria are met for CCyR until the date progressive disease (PD) is reported (or treatment is discontinued for PD) or death. Participants who neither discontinue due to PD nor die will be censored on the date of their last hematologic or cytogenetic assessment, whichever comes last. (Based on >=20 Metaphases)

PFS is defined as time from the first dosing date until the time PD is first documented by the investigator or death. Participants who die without a reported date of progression will be considered to have progressed on the date of death. Participants who neither progress nor die will be censored on the date of their last cytogenetic or hematologic assessment. Based on Kaplan-Meier methodology. Disease Progression was defined as any of the following criteria: -For CP-CML, progression to AP-CML or BP-CML while at highest tolerated dose -Increasing WBC -Loss of CHR (defined as any of the following: WBC count rises to >20.0x10^9/L; Platelet count rises to >600x10^9/L; appearance of extramedullary disease; appearance of >5% myelocytes+metamyelocytes in blood; appearance of blasts/promyelocytes in peripheral blood) -Loss of MCyR or increase in Ph+ bone marrow cells by >=30% from nadir -Death from any case during treatment.

Time to CHR is defined as the time from first dose of dasatinib until the first day CHR criteria are met, provided they are confirmed 4 weeks later, computed only for participants whose best response is CHR.

Duration of CHR will be computed from the first day all criteria are met for CHR, provided they are confirmed 4 weeks later, until the date progressive disease (PD) is reported (or treatment is discontinued for PD) or death. Participants who neither discontinue due to PD nor die will be censored on the date of their last hematologic assessment.

Disease free survival is defined as time from CCyR for participants with newly diagnosed chronic phase CML and for participants with chronic phase CML who are resistant or intolerant to imatinib (cohort 3 and cohort 1), and as time from CHR for participants with advanced phase CML and PH + ALL (cohort 2) until the time progression is first documented by the investigator or death from any cause. Based on Kaplan-Meier methodology. (CML: Chronic Myeloid Leukemia).

OS is defined as time from the first dosing date until the time of death. All participants will be followed yearly for survival for up to 5 years after treatment discontinuation. Participants who have not died or who are lost to follow-up will be censored on the last date the participant is known to be alive. Based on Kaplan-Meier methodology using graphs.

Molecular response was assessed using BCR-ABL transcript levels measurement by real-time quantitative polymerase chain reaction (qPCR). MMR for participants with the p210 BCR-ABL transcript variant was defined as a ratio BCR-ABL/ABL <= 10-3 or 0.1% on the international scale. In this study, ABL was used as the control-gene. For a participant with the p190 BCR-ABL transcript variant (occurring in Cohort 2 only), on-study assessments were compared to the participant's individual baseline BCR-ABL/ABL ratio and a reduction to < 0.1% or a 3-log reduction from baseline was considered an MMR.

Molecular response was assessed using BCR-ABL transcript levels measurement by real-time quantitative polymerase chain reaction (qPCR). (CMR) is defined as absence of BCR-ABL rearrangements by real-time qPCR analysis. The percentage of treated participants with CMR is reported by arm.

Major Cytogenetic Response (MCyR) rate is defined as the proportion of all treated participants who achieved a complete (0%) or partial (1%-35% Ph+ metaphases in at least 20 metaphases in bone marrow) cytogenetic response. The percentage of treated participants with MCyR is reported by arm.

Complete Cytogenetic Response (CCyR) rate is defined as the proportion of all treated participants who achieve a CCyR while on-study. CCyR rate is defined as 0% Ph+ metaphases in at least 20 metaphases in bone marrow. The percentage of treated participants with CCyR is reported by arm.

Molecular response will be assessed using BCR-ABL transcript levels measurement by real-time qPCR. MMR for participants with the p210 BCR-ABL transcript variant is defined according to the recommendations of Hughes et al. as a ratio BCR-ABL/ABL <= 10-3 or 0.1% on the international scale proposed by the authors. The standardized baseline, as established in the IRIS trial, is taken to represent 100% on the international scale and a 3-log reduction in ratio (BCR-ABL transcripts/ABL or BCR) from the standardized baseline (MMR) is fixed at 0.1%. In this study, ABL or other housekeeping gene, will be used as the control-gene. For a participant with the p190 BCR-ABL transcript variant, on-study assessments will be compared to the participant's individual baseline BCR-ABL/ABL ratio and a reduction to < 0.1% or a 3-log reduction from baseline will be considered an MMR. The percentage of treated participants with MMR is reported by arm.

Molecular response will be assessed using BCR-ABL transcript levels measurement by real-time quantitative polymerase chain reaction (qPCR). (CMR) is defined as absence of BCR-ABL rearrangements by real-time qPCR analysis. The percentage of treated participants with CMR is reported by arm.