SAN DIEGO — A polygenic score can link outcomes in Black pediatric patients with acute myeloid leukemia (AML) to genetic traits that arise more frequently in this population, new data reveal.
The score, dubbed ACS10 and initially highlighted in a 2022 report, predicts how well patients will respond to cytarabine based on their genetic make-up, and has the potential to personalize treatment for Black pediatric patients, a group that often has worse outcomes than White patients.
In the current study, presented at the annual meeting of the American Society of Hematology (ASH) , Black patients with low ACS10 scores had significantly worse outcomes compared with those with high scores when initially treated with low-dose cytarabine, daunorubicin, and etoposide.
The difference in outcomes disappeared, however, for patients who received high-dose cytarabine, daunorubicin, and etoposide or clofarabine and cytarabine.
The genetic traits revealed by the test likely help explain why Black patients with AML typically fare worse on certain regimens, Cynthia E. Dunbar, MD, chief of the Translational Stem Cell Biology Branch at the National Heart, Lung, and Blood Institute, commented in an ASH press preview briefing.
This study also suggests that clinicians should perform testing for genetic variants and biomarkers that impact outcomes "instead of assuming that a certain dose should be given simply based on perceived or reported race or ethnicity," said Dunbar, also secretary of ASH.
The ACS10 test, derived from a combination of 10 single nucleotide polymorphisms, is not yet available, but one could be developed to help guide treatment decisions for clinicians, especially those in developing countries where AML treatment can be very expensive, said study lead author Jatinder Lamba, PhD, MSc, of the University of Florida College of Pharmacy, Gainesville, at an ASH press briefing on Thursday.
Prior research shows that Black pediatric patients with AML often have worse outcomes than White patients. A recent study , for instance, found Black patients with AML, especially those aged 18 to 29 years, had a higher early death rate compared with White patients (16% vs 3%) and significantly lower 5-year overall survival rates (22% vs 51%). The authors of this study suggested that genetic differences between young Black and White patients could help explain the disparity.
In the new analysis, Lamba and colleagues explored how outcomes by race and cytarabine pharmacogenomics varied in pediatric patients with AML.
The study included 86 Black patients and 359 White patients with newly diagnosed AML treated on two multi-institutional clinical trials. The patients received one of three initial treatments that included cytarabine: high-dose or low-dose cytarabine, daunorubicin, and etoposide, or clofarabine and cytarabine.
Most Black patients in the analysis (73%) had low ACS10 scores compared with 30% of White patients.
Unlike other recent reports, this study found that Black and White patients had similar complete remission rates following two courses of induction therapy (92.6% vs 95%) as well as similar rates of minimal residual disease negativity after one course (55.8% vs 55.4%).
Event-free survival (EFS) and overall survival rates were also similar, with 5-year EFS estimates at 58.3% for Black patients and 58.2% for White patients and overall survival rates at 63.8% vs 69.4%, respectively (P = .24).
However, when separating outcomes by ACS10 scores, Black patients with low scores had significantly worse EFS following low-dose cytarabine, daunorubicin, and etoposide compared with those with high ACS10 scores. And when these patients received high-dose cytarabine, daunorubicin, and etoposide or clofarabine and cytarabine induction therapy instead, the differences went away.
Overall, Black patients demonstrated significantly better EFS following treatment with clofarabine and cytarabine compared with the low-dose cytarabine triple therapy (hazard ratio, 0.17; P = .01). After adjusting for cofounders, clofarabine and cytarabine induction was the best treatment for Black patients with low ACS10 scores (HR for EFS, 0.2).
"Our results suggest that pharmacogenomics differences between Black and White patients should be considered when tailoring induction regimens to improve outcomes of Black patients and bridge the racial disparity gap in AML treatment," the researchers concluded.
In developing countries, especially in Africa, starting patients on high-dose cytarabine, daunorubicin, and etoposide can lead to better results "without increasing much of the economic burden" since this treatment is the cheapest, Lamba said. "At the same time, if the patients have high ACS10 score, you can reduce their economic burden by giving them standard dose" cytarabine, daunorubicin, and etoposide and achieve similar results.
No study funding was reported. Lamba reported no relevant financial relationships, and three other authors reported various disclosures. Disclosures for Dunbar were unavailable.
Randy Dotinga is a freelance medical writer and board member of the Association of Health Care Journalists.
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