|The following article features coverage from the American Society of Clinical Oncology 2019 meeting. Click here to read more of Cancer Therapy Advisor‘s conference coverage.|
Flumatinib — a derivative of imatinib — may have superior efficacy compared with imatinib as frontline treatment in patients with chronic myeloid leukemia in chronic phase, according to the results of an open-label, randomized phase 3 study presented at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois. Both therapies had comparable safety profiles, the researchers found.
In the study (ClinicalTrials.gov Identifier: NCT02204644), 400 patients with newly diagnosed chronic myeloid leukemia in chronic phase were randomized to receive flumatinib or imatinib. The full-set analysis included 393 patients, 196 of whom received flumatinib 600 mg and 197 who received imatinib 400 mg tablets once daily for 12 months. The researchers measured major molecular response rates at 3 months, 6 months, and 12 months, designating the last 2 time points as primary endpoints. The laboratory where the rates were assessed was blinded to treatment allocations while the study was being conducted. The investigators examined efficacy endpoints for the intention-to-treat patients.
Flumatinib led to a much higher induction of major molecular response rate at both 6 months and 12 months, and at 3 months as well. At 6 months, the response rate among patients who received flumatinib was 35.2 compared with the rate of 19.3 among those who received imatinib (P =.0002). At 12 months, the response rate for patients who received flumatinib was 57.2 compared with the rate of 39.2 for those who received imatinib (P =.0010). At 3 months, the response rate for those who received flumatinib was 8.3 (4.33-12.00) compared with the rate of 2.1 (0.06-4.00) among those who were given imatinib (P =.0060).
A significantly greater proportion of patients in the flumatinib group had a complete molecular response (BCR-ABLIS ≤0.0032%) at 12 months than in the imatinib group.
Both treatments had similar safety profiles. Of 198 patients in the flumatinib arm, 112 (56.57%) experienced grade 3/4 treatment emergent adverse events; in the imatinib arm, 87 of 196 patients (41.38%) experienced such adverse effects. But the frequencies of some nonhematological and hematological adverse events were much lower in the flumatinib arm compared with the imatinib arm. Examples included rash (6% in the flumatinib arm compared with 14% in the imatinib arm), eyelid edema (0.51% in the flumatinib arm vs 14.65% in the imatinib arm), leukopenia (31% in the flumatinib arm compared with 60% in the imatinib arm) and neutropenia (30.10% in the flumatinib arm vs 59.60% in the imatinib arm). There were no treatment-emergent adverse events specific to any particular arm.
The flumatinib arm had a higher rate of diarrhea compared with the imatinib arm, noted study coauthor Bingcheng Liu, MD, of the Blood Diseases Hospital in Tianjin, China. In the flumatinib arm, the rate of this adverse event was 40%, compared with 11% in the imatinib arm. However, Dr Liu noted, 93% of all diarrhea cases in the flumatinib arm were grade 1.
Overall, “Flumatinib had a better safety profile with significantly lower rates of edema, pain in extremities, rash, neutropenia, and hypophosphatemia,” Dr Liu said.
Correction: This article was updated to reflect a change in the person presenting the research.
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Li Z, Meng L, Zhang Y, et al. Frontline flumatinib versus imatinib in patients with chronic myeloid leukemia in chronic phase: Results from the China randomized phase III study. Presented at: 2019 American Society of Clinical Oncology (ASCO) Annual Meeting; May 31-June 4, 2019; Chicago, IL. Abstract 7004.