The Effectiveness of Tyrosine Kinase Inhibitors and Molecular Monitoring Patterns in Newly Diagnosed Patients With Chronic Myeloid Leukemia in the Community Setting

Abstract

Background: Clinical outcomes of patients with chronic myeloid leukemia (CML) treated in clinical trials, including response to therapy, may not be representative of those treated in a community setting. Thus, we sought to determine the real-world effectiveness of first-line tyrosine kinase inhibitors in CML by evaluating response rates, all-cause discontinuation, and adherence. Response monitoring patterns were also analyzed.

Patients and methods: This retrospective observational study, using the McKesson Specialty Health/US Oncology Network (MSH/USON) iKnowMed electronic health record database and medical charts, identified newly diagnosed CML patients who received first-line imatinib, dasatinib, or nilotinib from July 2007 to March 2011, and were then followed for ≥ 18 months.

Results: Three hundred patients met study criteria (222 imatinib-treated, 34 dasatinib-treated, and 44 nilotinib-treated in the first-line). Molecular and cytogenetic response assessments were conducted less frequently than recommended (40% never had cytogenetic or molecular monitoring at any time). Patients treated with either dasatinib or nilotinib experienced higher response rates by 6, 12, and 18 months, faster time to major molecular response, and a significantly lower rate of all-cause treatment discontinuation within 18 months relative to imatinib-treated patients. Approximately 56% of all patients were adherent to tyrosine kinase inhibitor therapy.

Conclusion: Dasatinib and nilotinib were more effective than imatinib as first-line therapy for CML in a community setting, as observed in descriptive and univariate analyses. The frequency of cytogenetic and molecular monitoring was lower than that recommended by current guidelines, including patients with no molecular or cytogenetic assessments during the 18-month follow-up. Therefore, MSH/USON is working toward improving compliance with response monitoring guidelines.

Keywords: Adherence; Dasatinib; Frequency of response assessments; Imatinib; Nilotinib.