MMolR is defined as reduction in transcript levels of the breakpoint cluster region (BCR)-V-abl Abelson murine leukemia viral oncogene homolog 1 (ABL) gene of at least 3 log. The BCR-ABL gene has a role in the production of a mutated protein that converts bone marrow stem cells from normal to leukemic.

Efficacy analyses as originally described in the protocol were not conducted because of the low number of participants enrolled.

AE=any new untoward medical occurrence or worsening of a preexisting medical condition that does not necessarily have a causal relationship with treatment. SAE=any untoward medical occurrence that at any dose results in death, persistent or significant disability/incapacity, drug dependency, or drug abuse; prolongs inpatient hospitalization; or is life-threatening, a congenital anomaly/birth defect, or an important medical event. Treatment related=possibly, probably, or certainly related to and of unknown relationship to study treatment.

All participants who received at least 1 dose of dasatinib or imatinib.

GI=gastrointestinal. AE=any new untoward medical occurrence or worsening of a preexisting medical condition that does not necessarily have a causal relationship with treatment. Grade 1=mild; Grade 2=moderate; Grade 3=severe and undesirable; Grade 4=life-threatening or disabling; Grade 5=death. Percentages based on the number of participants with a specific grade at baseline. Participants without on-study test values for a particular laboratory analyte are not included in the reporting of that analyte.

All participants who received at least 1 dose of dasatinib or imatinib.

Time to MMolR is defined as the time from first treatment dose until measurement criteria are first met for MMolR. MMolR is defined as a reduction in transcript levels of the BCR-ABL gene of at least 3 log from baseline.

Efficacy analyses as originally described in the protocol were not conducted because of the low number of participants enrolled.

Cytogenetic response is based on the prevalence of Ph+ metaphases among cells in metaphase in a bone marrow sample.

Efficacy analyses as originally described in the protocol were not conducted because of the low number of participants enrolled.

Time to treatment failure is defined as the time in days from randomization to progressive disease documented by the investigator, to death from any cause without prior progression, or to early treatment discontinuation for any reason, whichever occurs first. Participants without disease progression or who do not die and complete the 12-month study treatment are censored on the date of their last molecular, cytogenetic, or hematologic assessment.

Efficacy analyses as originally described in the protocol were not conducted because of the low number of participants enrolled.

Progression-free survival is defined as the time in days from randomization to progressive disease documented by the investigator or to death from any cause without prior progression. Participants without progressive disease or who do not die and complete the 12-month treatment are censored on the date of their last molecular, cytogenetic, or hematologic assessment.

Efficacy analyses as originally described in the protocol were not conducted because of the low number of participants enrolled.