Radotinib demonstrated significantly higher and faster rates of complete cytogenetic responses and major molecular responses than imatinib in patients with a manageable safety profile in patients with newly diagnosed chronic myeloid leukemia in chronic phase (CML-CP).1
Radotinib is a second generation BCR-ABL1 tyrosine kinase inhibitor (TKI) approved in Korea for the treatment of patients with CML-CP who have failed prior TKIs. Researchers sought to evaluate the efficacy and safety of radotinib compared with imatinib for frontline treatment of newly diagnosed CML-CP.
For the open-label, phase 3 trial, researchers enrolled 241 patients and randomly assigned them 1:1:1 to receive radotinib 300 mg twice daily, radotinib 400 mg twice daily, or imatinib 400 mg once daily.
Results showed that by 12 months of follow-up, the major molecular response rate was 51.9% with radotinib 300 mg (P = .0044) and 45.7% with radotinib 400 mg (P = .0342) compared with 29.6% with imatinib. The median time to major molecular response among responders was 5.7 months, 5.6 months, and 8.2 months, respectively.
Researchers found that the complete cytogenetic response rates by 12 months were also higher with radotinib 300 mg (91.1%; P = .0120) compared with imatinib (76.5%) and no patients progressed to accelerated phase or blast crisis by 12 months in any group.
In terms of safety, the most common adverse events with radotinib were rash, nausea/vomiting, headache, and pruritus, while edema, myalgia, nausea/vomiting, and rash were most frequent with imatinib. Grade 3 or 4 thrombocytopenia occurred in 16.5% of patients in the radotinib 300 mg group, 13.6% of those in the radotinib 400 mg group, and 19.8% of those receiving imatinib. Grade 3 or 4 neutropenia occurred in 19.0%, 23.5% and 29.6% of patients, respectively.
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The study also demonstrated that 8.8%, 19.8%, and 6.2% of patients receiving radotinib 300 mg, radotinib 400 mg, and imatinib, respectively, discontinued treatment due to adverse events or laboratory abnormalities.
- Kwak J-Y, Kim H, Kim JA, et al. Efficacy and safety of radotinib compared with imatinib in newly diagnosed chronic phase chronic myeloid leukemia patients: 12 months result of phase 3 clinical trial [abstract]. Blood. 2015;126(23):476.