CHICAGO – Major molecular response rates at 12 months were better among chronic myeloid leukemia patients treated with dasatinib/nilotinib vs. imatinib for first-line therapy, and among patients enrolled vs. not enrolled in clinical trials, in a retrospective review of patients treated with first-line tyrosine kinase inhibitors between 2002 and 2014.
The overall rates of major molecular response (MMR) at 12 and 24 months in the 51 patients in the study were 23.5% (12 patients) and 44.9% (22 patients), which was comparable to historical data, Dr. Isabelle Phuong Le reported in a poster at the American Society of Hematology Meeting on Hematologic Malignancies.
The MMR rate among those treated with dasatinib/nilotinib first line was 53%, compared with 10% for those treated with imatinib, said Dr. Le of the University of Texas Health Science Center, San Antonio.
Further the MMR rates at 12 and 24 months among those enrolled vs. not enrolled in clinical trials were 83% vs 15% and 100% vs. 45%, respectively, she noted.
Patients in the analysis were adults with a mean age of 44.6 years who had chronic phase chronic myeloid leukemia (CML). Almost half (49%) were Hispanic, and 56.9% were women. Two-thirds (66.7%) received imatinib first line, and 33.3% received dasatinib/nilotinib first line. More than a third (37.2%) were younger than age 40 years, 15% had a language barrier, and 11.7% were enrolled in clinical trials.
No differences in the MMR rates at 12 and 24 months were seen between Hispanics and non-Hispanics, those with and without language barrier, or men and women, nor were any differences seen between those with more than three lines of therapy and those with three or fewer lines of therapy, or between patients older vs. younger than 40 years, although there was a trend toward improved response rates in older patients, she noted.
“Our patients have similar MMR rates at 12 months and 24 months compared to historical data,” Dr. Le wrote, noting that the findings regarding improved MMR rates with dasatinib/nilotinib were expected.
The findings regarding improved MMR rates among those enrolled in clinical trials could be due to “selective patients as clinical trial patients, more controlled and monitored treatment, frequent follow-ups, and better education regarding disease and treatment,” she said, concluding that “ we can improve treatment response rates in our patients with better disease education.”
Dr. Le reported having no disclosures.