Shin Fujisawa 1 , Yasunori Ueda 2 , Kensuke Usuki 3 , Hajime Kobayashi 4 , Eisei Kondo 5 , Noriko Doki 6 , Takafumi Nakao 7 , Yoshinobu Kanda 8 , Nobuharu Kosugi 9 , Hiroshi Kosugi 10 , Takashi Kumagai 11 , Hiroshi Harada 12 , Masato Shikami 13 , Yasuhiro Maeda 14 , Toru Sakura 15 , Koiti Inokuchi 16 , Akio Saito 17 , Yuichiro Nawa 18 , Masahiro Ogasawara 19 , Junji Nishida 20 , Takeshi Kondo 21 , Chikashi Yoshida 22 , Hiroyuki Kuroda 23 , Yoko Tabe 24 , Yoshinobu Maeda 25 , Kenji Imajo 26 , Kensuke Kojima 27 , Satoshi Morita 28 , Sho Komukai 29 , Atsushi Kawaguchi 30 , Junichi Sakamoto 31 , Shinya Kimura , 27
12 November 2018
Treatment-free remission (TFR), the ability to maintain a molecular response (MR), occurs in approximately 50% of patients with chronic myelogenous leukemia (CML) treated with tyrosine kinase inhibitors (TKIs).
A multicenter phase 2 trial (Delightedly Overcome CML Expert Stop TKI Trial: DOMEST Trial) was conducted to test the safety and efficacy of discontinuing imatinib. Patients with CML with a sustained MR of 4.0 or MR4.0-equivalent for at least 2 years and confirmed MR4.0 at the beginning of the study were enrolled. In the TFR phase, the international scale (IS) was regularly monitored by IS-PCR testing. Molecular recurrence was defined as the loss of MR4.0. Recurrent patients were immediately treated with dasatinib or other TKIs including imatinib.
Of 110 enrolled patients, 99 were evaluable. The median time from diagnosis to discontinuation of imatinib was 103 months, and the median duration of imatinib therapy was 100 months. Molecular recurrence-free survival rates were 69.6%, 68.6% and 64.3% at 6, 12, and 24 months, respectively. After discontinuation of imatinib therapy, 26 patients showed molecular recurrence, and 25 re-achieved deep MR after dasatinib treatment. Molecular response MR4.0 was achieved in 23 patients within 6 months and 25 patients within 12 months. Multivariate analysis revealed that a longer time from diagnosis to discontinuation of imatinib therapy ( p = 0.0002) and long duration of imatinib therapy ( p = 0.0029) predicted a favorable prognosis.