The main goal of this study was to describe treatment patterns of patients with chronic myeloid leukemia (CML) who were treated with tyrosine kinase inhibitors (TKIs) in Japan.

This was a retrospective observational study with secondary use of data from the Medical Data Vision (MDV) hospital-based database. The index date was the date of the first prescription of any TKI of interest registered within the selection period (01 January 2011 to 31 December 2019). The follow-up period was from the index date until the end of the study period, end of continuous follow-up in the MDV database, or death, whichever came first.

Patients who met all the below inclusion criteria and none of the exclusion criteria were included in the study.

Inclusion criteria:

• Patients who had at least one TKI prescription during the selection period,
• a confirmed diagnosis of chronic phase CML recorded before or at the index date,
• were aged 15 years or older at the index date, and
• had at least 12-months continuous pre-index period.

Exclusion criteria:

• Patients who had at least one TKI prescription in the 12 months preceding the index date (washout period to catch the 1st line of treatment [LoT]),
• a confirmed diagnosis of CML blast crisis or accelerated phase recorded prior to, at, or within 6 months after the index date,
• a confirmed diagnosis of acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL) within 6 months after the index date,
• a medical record of chemotherapy (not including hydroxyurea) within 6 months after the index date,
• a stem cell transplant procedure recorded during the pre-index period.

This was a retrospective, non-interventional cohort study.