Retrospective, non-interventional observational cohort study conducted among patients with CML.

A retrospective, non-interventional cohort study was used to address the study objectives. A cohort of adult patients with CML who were treated with TKIs were identified using the IBM® MarketScan® Commercial and Medicare Supplemental databases (commercial claims; the MarketScan database) to have a better understanding of real-world treatment patterns, HRU and healthcare costs among patients with CML treated with later lines of therapy (i.e., third line or later).

For Phase I, the IBM® MarketScan® Commercial Claims and Encounters and Medicare Supplemental Databases were used (commercial claims). The commercial claims covered the period from 01/01/2001 to 06/30/2019.

The study consisted of the following periods:

• The baseline period was defined as the 6-month period before the first line therapy initiation for CML.
• The observation period was defined as the period of at least 12 months from the first CML diagnosis to the end of data availability or end of health plan coverage, whichever occurs first; the observation period varied by patient.

Inclusion Criteria:

Patients were selected for the analysis of later lines of therapy in commercial claims (i.e., were previously treated with TKIs, who are relapsed/refractory to/intolerant of TKIs) if they met the following criteria:

• Had at least one diagnosis for CML, with first CML diagnosis observed in claims on or after May 10, 2001, the date of FDA approval for imatinib
• Were at least 18 years of age as of the first CML diagnosis
• Started a first line therapy for CML with imatinib, dasatinib, nilotinib, or bosutinib (conditional on FDA-approval dates)
• Initiated first line therapy within a maximum of 1 month prior to the first diagnosis for CML or a maximum 3 months following the first diagnosis for CML
• Had continuous health plan enrollment (pharmacy and medical benefits) from the washout period to at least 12 months following the first CML diagnosis

Exclusion Criteria:

• Patients had a diagnosis for CML remission or relapse anytime prior to first line therapy
• Patients had a medical claim associated with a clinical trial during the washout period up to the end of the observation period
• Patients had an HSCT during the washout period up to the first line therapy initiation
• Patients had chemotherapy treatment (except hydroxyurea) during the washout period up to the first line therapy initiation

The study was conducted among patients with CML.