Report from the American Society of Clinical Oncology (ASCO), Chicago IL, May 29-June 2, 2015 – Tyrosine kinase inhibitors (TKIs) have changed the face of treatment, transforming CML into a manageable illness where once it was deadly. But two studies presented at ASCO 2015 suggest that the benefits of treatment are not equally shared.
The first study looked at survival in different ethnic groups living with CML in the U.S. (Uprety and colleagues. ASCO 2015; abstract 7063). Information was obtained from a large cancer database called SEER (for Surveillance, Epidemiology, and End Results). The time periods compared were 1990-2000 BG (before Gleevec), and 2001-2006 (after TKIs became available). Data were available for almost six thousand people, including 394 African-Americans.
Among those aged 65 years or older, the likelihood of survival increased substantially, but only among Caucasians. No survival benefit was seen among African-Americans after TKIs were introduced. A survival benefit was found for African-Americans of different ages in a separate study, but survival was significantly poorer among young African-American women compared to young white women (Mandal and colleagues. Acta Oncol 2013;52:837-841).
CML is more common in Caucasians compared to African-Americans or Hispanic-Americans (Matasar and colleagues. Leuk Lymphoma 2006;47:2365-2370). There is no evidence to suggest that non-white ethnic groups have a poorer response to TKIs. So the most likely reason for the difference in survival is poorer access to effective medications.
A second study at ASCO examined barriers to care in South Texas (Phuong and colleagues. ASCO 2015; abstract e18046). The treatment response rate among Hispanics was similar to what has been seen in clinical trials (which primarily enroll Caucasians). However, those who did best were people enrolled in clinical trials, suggesting that closer monitoring in daily practice might further improve the likelihood of achieving a treatment response.