Outcome of Philadelphia chromosome-positive chronic myeloid leukemia in the United States since the introduction of imatinib therapy-The Surveillance, Epidemiology, and End Results database, 2000-2019.

BACKGROUND

Since the introduction of BCR::ABL1 tyrosine kinase inhibitors (TKIs) in 2000, the treatment of Philadelphia chromosome (Ph)-positive chronic myeloid leukemia (CML) has improved significantly.

METHODS

This study aimed to evaluate Ph-positive CML outcomes in the TKI therapy era, considering factors like age, ethnicity, and income. Using the Surveillance, Epidemiology, and End Results (SEER) database, 2857 patients with Ph-positive CML diagnosed from 2000 to 2019 were analyzed.

RESULTS

The overall 5-year survival rates in Ph-positive CML increased to above 80%, compared with pre-TKIs historical data reporting 5-year overall survival (OS) rates of less than 50%. The 5-year OS rate was 73% for patients diagnosed in 2000-2004, 82% in 2005-2009, and 78% in 2010-2014; the 4-year OS rate was 83% in 2015-2019. The 5-year OS rate for younger patients (<60 years old) was 88% in 2000-2009 and 90% in 2010-2019 (p value .426). In older patients (60+ years old), the 5-year OS rates were 64% and 65%, respectively (p value, .303). Lower household income was associated with inferior survival across the 2000-2019. These results are inferior to European studies where TKIs are universally available and affordable, and relative OS in CML is similar to age-matched normal populations.

CONCLUSIONS

Although the outcome of Ph-positive CML has improved significantly since 2000, the SEER data still shows differences in outcomes among patient subsets, some anticipated (worse OS in older patients accounted by the relative OS), but others that suggest less than universal access and affordability of this therapy (among poorer patients) in the United States.