An Extension Study to Determine the Efficacy and Safety of STI571 in Participants With Chronic Myeloid Leukemia Who Are Refractory to or Intolerant of Interferon-Alpha

Inclusion criteria

Participants included in the study were:

• Consenting males or females greater than or equal to (≥)18 years of age with Philadelphia chromosome positive (Ph+) chronic myeloid leukemia (CML).
• With a documented failure of interferon-alpha (IFN) or an IFN-containing therapy, characterized as resistance or refractoriness defined as any of the following:

• Hematologic Resistance - Failure to achieve a complete hematological response (CHR), lasting for at least 1 month despite 6 or more months of IFN or an IFN-containing regimen, in which IFN was administered at a dose of at least 25 million international units (MIU) per week. During this treatment period the cumulative duration of hydroxyurea therapy may not have exceeded 50% of the treatment period with the IFN-containing regimen.
• Cytogenetic Resistance - Bone marrow cytogenetics showing ≥65% Ph+ after one year of IFN-based therapy,
• Cytogenetic Refractoriness - An increase in the Ph+ chromosome in BM cells by at least 30 percentage points (e.g. from 20% to 50%, or from 30% to 60%) confirmed by two samples at least 1 month apart, or an absolute increase to ≥65%,
• Hematologic Refractoriness - A rising white blood cell count (WBC) [to a level ≥20 x 10^9/L confirmed by two samples taken at least two weeks apart] for participants achieving a complete hematologic response while receiving IFN or an IFN-containing regimen. This regimen must have included IFN at a dose of at least 25 MIU administered per week. During this treatment period the cumulative duration of hydroxyurea therapy may not have exceeded 50% of the treatment period with the IFN-containing regimen.

In this report all refractory populations were referred to as "relapsed" populations.

• With a documented intolerance to IFN therapy defined as a ≥Grade 3 non-hematologic toxicity persisting for at least one month, for participants receiving IFN or an IFN- containing regimen. IFN was to be administered at a dose of at least 25 MIU/week. Participants who were intolerant of IFN were to have been diagnosed ≥6 months prior to the time of entry into the study.

Exclusion criteria

Participants excluded from the study were:

• Females of childbearing potential without a negative pregnancy test prior to the initiation of study drug. Barrier contraceptive precautions were to be used throughout the trial in both sexes.
• With serum bilirubin and creatinine concentrations more than twice the upper limit of the normal range (ULN).
• With serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) more than twice the ULN.
• With >15% of blasts or basophils in peripheral blood (PB) or bone marrow (BM).
• With ≥30% of blasts plus promyelocytes in PB or BM.
• With a platelet count of less than (<)100 x 10^9/L.
• With an Eastern Cooperative Oncology Group (ECOG) Performance Status Score ≥3.
• Receiving busulfan within 6 weeks of Day 1.
• Receiving treatment with IFN or cytosine arabinoside (Ara-C) within 14 days of Day 1.
• Receiving treatment with hydroxyurea within 7 days of Day 1.
• Receiving other investigational agents within 28 days of Day 1.
• With prior marrow or stem cell transplantation.