Open-Label Study Evaluating Dasatinib Therapy Discontinuation in Patients With Chronic Phase Chronic Myeloid Leukemia With Stable Complete Molecular Response

Event-free survival (EFS) rate is defined as the percentage of surviving participants with no loss of Major Molecular Response (MMR) at the specified timepoints after dasatinib discontinuation. MMR is defined as BCR-ABL transcripts < 0.1% IS. Loss of MMR is defined per the European LeukemiaNet (ELN) definition of progression. Progression is defined as Transformation to Accelerated Phase or Blast Crisis (AP/BC):

Accelerated Phase (AP) Blasts in PB or BM 15-29%; Blast + promyelocytes ≥ 30% with blasts < 30% or ACA in Ph+ cells (clonal progression), or basophils in blood ≥ 20%,or platelets < 100 x 10^9 /L unrelated to therapy

Blastic Phase or Crisis (BP/BC) Blasts in PB or BM ≥ 30%, or extramedullary blast cell involvement (with exception of spleen and liver)

The date of progression is defined as the date any of the above criteria is first met. Participants who have not progressed will be censored on the date of last examination.

RFS is the percentage of participants who did not relapse at the specified timepoints. Participants who did not relapse were censored on the date of their last molecular assessment. Relapse is defined as any of the following events while on study: the loss of Major Molecular Response (MMR), loss of Complete Cytogenetic Response (CCyR), loss of Complete Hematologic Response (CHR) or progression to advanced/blastic phase.

MMR is defined as BCR-ABL transcripts < 0.1% IS. Cytogenetic response (CyR) is based on the prevalence of Ph+ cells in metaphase from bone marrow (BM) sample based on evaluation of at least 20 metaphases. CCyR is defined as 0% Ph+ cells in metaphase in BM. CHR is obtained when all the following criteria are met in peripheral blood (PB) sampling: white blood cell ≤10,000/mm3; Platelets < 450,000/mm3; PB basophils <5%; No blasts or promyelocytes in PB; <5% myelocytes plus metamyelocytes in PB; No extramedullary involvement (including no hepatomegaly or splenomegaly).

Progression free survival (PFS) is defined as the percentage of participants who experienced death (due to any cause) or accelerated phase, or blast crisis. Participants who neither progress nor die will be censored on the date of their last molecular assessment. Progression is defined as Transformation to Accelerated Phase or Blast Crisis (AP/BC) Accelerated Phase (AP) Blasts in PB or BM 15-29%; Blast + promyelocytes >= 30% with blasts < 30% or ACA in Ph+ cells (clonal progression), or basophils in blood >= 20%,or platelets < 100 x 109 /L unrelated to therapy Blastic Phase or Crisis (BP/BC) Blasts in PB or BM >= 30%, or extramedullary blast cell involvement (with the exception of spleen and liver)

The number of participants who did not lose major molecular response (MMR) 60 months after discontinuing study treatment who were in MR4.5 at the time of discontinuation and lost MR4.5. Molecular response will be assessed using BCR-ABL transcript levels measurement by real-time quantitative polymerase chain reaction (Q-PCR). MMR is defined as BCR-ABL transcripts < 0.1% Internal Standard (IS). CMR (MR4.5) defined as ≤ 0.0032% (IS) or ≥ 4.5 log reduction of BCR-ABL transcript levels molecular response.

Assessment of BCR-ABL kinetics in patients who are in CMR (MR4.5) or less when transcript levels are still measurable. CMR (MR4.5) defined as ≤ 0.0032% (IS) or ≥ 4.5 log reduction of BCR-ABL transcript levels molecular response.

Time to Transformation to AP/BC is defined as the rate at which participants experienced transformation to accelerated phase/blast crisis (AP/BC) since discontinuation. Participants who did not develop to AP, late phase, or BC phase were censored on their last molecular measurement date.

Overall survival (OS) is defined as the time from dasatinib treatment discontinuation to the date of death (due to any cause) or last known alive date. Participants who do not die will be censored on their last known alive date.

Progression-free survival (PFS) is defined as the time from treatment discontinuation to the date of progression or death (due to any cause), whichever occurs first. Participants who neither progress nor die will be censored on the date of their last molecular assessment.