In a study using Surveillance, Epidemiology, and End Results (SEER)-Medicaid data reported in the Journal of Clinical Oncology, Winn et al found that 68% of Medicare patients with chronic myeloid leukemia (CML) initiated tyrosine kinase inhibitor treatment within 180 days after diagnosis.
Factors in Initiation
The study involved data from 393 patients diagnosed with CML between 2007 and 2011. Of them, 68% initiated tyrosine kinase inhibitor treatment within 180 days after diagnosis. Factors associated with earlier initiation of tyrosine kinase inhibitors were receipt of cost-sharing subsidies (hazard ratio [HR] = 1.35, 95% confidence interval [CI] = 1.05–1.84), diagnosis in more recent years (HR = 1.14, 95% CI = 1.04–1.22), and living in a big metropolitan area (HR = 1.80, 95% CI = 1.00–3.78) or metropolitan area (HR = 1.84, 95% CI = 1.02–3.89) vs an urban area.
Higher levels of comorbidity (HR = 0.81, 95% CI = 0.72–0.89) and age > 80 vs < 70 years (HR = 0.53, 95% CI = 0.38–0.72) were associated with later initiation of tyrosine kinase inhibitors.
Adherence defined as ≥ 80% of days covered during 6 months after tyrosine kinase inhibitor initiation was found in 61% of patients initiating treatment. Age > 80 years vs < 70 years was associated with reduced adherence (adjusted risk ratio [RR] = 0.74, 95% CI = 0.56–0.94), and a more recent year of diagnosis was associated with increased adherence (adjusted RR = 1.07; 95% CI = 1.01–1.13, per year).
The investigators concluded: “Only 68% of Medicare beneficiaries with CML initiated [tyrosine kinase inhibitor] therapy within 6 months of diagnosis. Delayed initiation among individuals without cost-sharing subsidies suggests that out-of-pocket costs may be a barrier to timely initiation of therapy among individuals diagnosed with CML.”
The study was supported by a Comparative Effectiveness Research Strategic Initiative of the University of North Carolina (UNC) Clinical and Translational Science award, the UNC School of Medicine, the National Institutes of Health, the Royster Society of Fellows at UNC Chapel Hill, and the National Cancer Institute.
Stacie B. Dusetzina, PhD, of UNC at Chapel Hill, is the corresponding author of the Journal of Clinical Oncology article.