Clinical Efficacy and Safety of First-Line Dasatinib Therapy and the Relevance of Velocity of BCR-ABL1 Transcript Decline for Achievement of Molecular Responses in Newly Diagnosed Chronic-Phase Chronic Myeloid Leukemia: Report from the Juntendo Yamanashi

The use of tyrosine kinase inhibitors led to an improvement in the prognoses of patients with chronic myeloid leukemia (CML). The aims of this study were to investigate the efficacy and safety of dasatinib in Japanese patients and to explore the factors that affect the achievement of molecular responses. The primary endpoint was a major molecular response (MMR) by 12 months. The halving time for BCR-ABL1 transcripts was calculated using transcript levels. Thirty-two patients with chronic-phase CML (CML-CP) were enrolled and 30 received 100 mg dasatinib once daily. At 24 months of follow-up, 21 (72%) and 24 (83%) patients achieved an MMR by 12 and 24 months, respectively; the rates of a deep molecular response (DMR) by 12 and 24 months were 48 and 59%, respectively. A shorter halving time of BCR-ABL1 transcripts (≤10.6 days) accurately predicted both an MMR and a DMR. The incidence of pleural effusion was 50%. Our study reconfirmed the efficacy and safety of dasatinib treatment in Japanese patients with newly diagnosed CML-CP. In addition, the usefulness of the halving time of BCR-ABL1 transcripts was validated. These data emphasize the significance of an early treatment response in achieving a DMR during dasatinib therapy.

Takaku T ，Iriyama N ，Mitsumori T ，Sato E ，Gotoh A ，Kirito K ，Noguchi M ，Koike M ，Sakamoto J ，Oba K ，Komatsu N ... -  《-》

Shorter halving time of BCR-ABL1 transcripts is a novel predictor for achievement of molecular responses in newly diagnosed chronic-phase chronic myeloid leukemia treated with dasatinib: Results of the D-first study of Kanto CML study group.

To investigate the factors that affect molecular responses on dasatinib treatment in patients with chronic-phase chronic myeloid leukemia (CML-CP), we performed a clinical trial named the "D-First study." Fifty-two patients with newly diagnosed CML-CP were enrolled in this study and received 100 mg dasatinib once daily. A deep molecular response (DMR) was defined as <50 copies/μg RNA of BCR-ABL1 transcript value corrected by GAPDH, which ensures <0.01% of BCR-ABL1 transcript value according to International Scale (BCR-ABL1(IS)). The halving time for BCR-ABL1 transcripts was calculated using transcript levels before dasatinib treatment, transcript levels after 3 months of treatment, and the treatment time between these two points. In terms of molecular response, 38 of 51 (75%) patients reached major molecular response (MMR) by 12 months, and the rate of DMR by 18 months was 59% (30/51). While both BCR-ABL1 transcript levels before treatment and a shorter halving time of BCR-ABL1 transcripts (≤14 days) were significant factors affecting achievement of MMR by 12 months, the Sokal score at diagnosis was not associated with MMR. Importantly, the halving time was the only factor that predicted achievement of DMR by 18 months. We showed that patients with CML-CP treated with dasatinib can be stratified according to the early treatment response as determined by the halving time of BCR-ABL1 transcripts. These data emphasize the significance of the early response from dasatinib treatment in achieving a DMR. (ClinicalTrials.gov; NCT01464411).

Iriyama N ，Fujisawa S ，Yoshida C ，Wakita H ，Chiba S ，Okamoto S ，Kawakami K ，Takezako N ，Kumagai T ，Inokuchi K ，Ohyashiki K ，Taguchi J ，Yano S ，Igarashi T ，Kouzai Y ，Morita S ，Sakamoto J ，Sakamaki H ... -  《-》

Rapid reduction in BCR-ABL1 transcript predicts deep molecular response in dasatinib-treated chronic-phase chronic myeloid leukaemia patients.

We conducted a phase-II study to evaluate the efficacy and safety of dasatinib in patients newly diagnosed with chronic-phase chronic myeloid leukaemia (CML-CP) in Japan (IMIDAS PART 2 study). Seventy-nine patients were administered 100 mg dasatinib once daily. We examined pretreatment and post-treatment influences of various factors. The BCR-ABL1 international scale (IS), halving time (HT) and reduction rate of BCR-ABL1 transcript within the initial 1 or 3 months of therapy (RR-BCR-ABL11m,3m ) were the post-treatment factors investigated to predict the molecular response. The estimated major molecular response (MMR), molecular response 4.0 (MR4.0) and molecular response 4.5 (MR4.5) rates were 77.2%, 49.4% and 35.4%, respectively, at 12 months. Grade 3/4 non-haematologic adverse events were infrequent. Multivariate analysis showed that age >65 years was significantly correlated with MR4.0 and MR4.5 (deep molecular response: DMR) at 12 months. All post-treatment factors at 3 months predicted DMR by univariate analysis. However, RR-BCR-ABL13m was the only significant landmark for predicting DMR by multivariate analysis. Primary treatment of CML-CP with dasatinib enabled early achievement of MMR and DMR, particularly in elderly patients, with high safety. Furthermore, RR-BCR-ABL13m was found to be a more useful predictor of DMR than HT-BCR-ABL1 and BCR-ABL1 IS.

Murai K ，Yamaguchi K ，Ito S ，Miyagishima T ，Shindo M ，Wakasa K ，Inomata M ，Nagashima T ，Kondo T ，Fujimoto N ，Yamamoto S ，Yonezumi M ，Oyake T ，Kowata S ，Tsukushi Y ，Mine T ，Meguro K ，Ikeda K ，Watanabe R ，Saito S ，Sato S ，Tajima K ，Chou T ，Kubo K ，Oba K ，Sakamoto J ，Ishida Y ，The Inter-Michinoku Dasatinib Study Group (IMIDAS) ... -  《-》

Dasatinib rapidly induces deep molecular response in chronic-phase chronic myeloid leukemia patients who achieved major molecular response with detectable levels of BCR-ABL1 transcripts by imatinib therapy.

Shiseki M ，Yoshida C ，Takezako N ，Ohwada A ，Kumagai T ，Nishiwaki K ，Horikoshi A ，Fukuda T ，Takano H ，Kouzai Y ，Tanaka J ，Morita S ，Sakamoto J ，Sakamaki H ，Inokuchi K ... -  《-》

Early BCR-ABL1 Reduction Is Predictive of Better Event-free Survival in Patients With Newly Diagnosed Chronic Myeloid Leukemia Treated With Any Tyrosine Kinase Inhibitor.

An early molecular response has a strong predictive value in chronic myeloid leukemia (CML). Recently, the halving time (velocity of early BCR-ABL1 transcript elimination) has been shown to represent an additional prognostic index. Our objective was the evaluation of the prognostic significance of the 3-month point in our population. We retrospectively collected BCR-ABL1 transcript data at different time points, events, and survival data of patients with CML treated at the Division of Hematology, San Luigi Hospital, University of Turin, Turin, Italy. Of 71 patients diagnosed from January 2005 to March 2015 in our center and treated with front-line tyrosine kinase inhibitors (imatinib, nilotinib and dasatinib), we selected those who had undergone a molecular evaluation at 3 months. The event-free survival (EFS) by the median follow-up time was the primary endpoint. The data from 50 patients with CML chronic phase were analyzed. Overall, 34 of the 50 patients (68%) had a transcript ≤ 10% at 3 months. Of those in the > 10% group, 63% had experienced an event compared with 12% in the ≤ 10% group by the median follow-up point (P < .001). The halving time threshold for discriminating between EFS was 17 days. None of the patients with a transcript > 10% at 3 months had a halving time of ≤ 17 days. Patients with BCR-ABL1 ≤ 10% and a halving time of ≤ 17 days had significantly better EFS than that of patients with BCR-ABL1 ≤ 10% and a halving time > 17 days and of patients with BCR-ABL1 > 10% (96% group 1 vs. 60% group 2 vs. 27% group 3; P < .001). Irrespective of the tyrosine kinase inhibitor used, the prognosis was significantly superior for patients with BCR-ABL1 ≤ 10% and halving time of ≤ 17 days. Our data revealed that the use of ABL1 as a control gene is reliable for the determination of the halving time in the clinical setting and highlight the importance of measuring the BCR-ABL1 transcript at CML diagnosis.

Fava C ，Rege-Cambrin G ，Dogliotti I ，Gottardi E ，Berchialla P ，Di Gioacchino B ，Crasto F ，Lorenzatti R ，Volpengo A ，Daraio F ，Fantino C ，Saglio G ... -  《-》