Imatinib provides durable molecular and cytogenetic responses in a practical setting for both newly diagnosed and previously treated chronic myelogenous leukemia: a study in nagasaki prefecture, Japan

Efficacy and Cardiovascular Adverse Events of Long-term Treatment with Tyrosine Kinase Inhibitors for Chronic Myeloid Leukemia: A Report from the Nagasaki CML Study Group

Objective The standard treatment for chronic myeloid leukemia (CML) is the continuous use of tyrosine kinase inhibitors (TKIs), which results in a favorable prognosis for the majority of patients. Recent studies have identified cardiovascular diseases (CVDs) as late adverse events (AEs) related to TKIs. In this study, we evaluated the long-term efficacy and AEs of TKIs, focusing on CVDs. Methods We performed a retrospective survey of CML patients (diagnosed from 2001 to 2016) treated with TKIs in Nagasaki Prefecture. Clinical data were obtained from their medical records. We analyzed the survival, estimated cumulative incidence of CVDs, and risk factors for CVD among CML patients treated with TKIs. Results The overall survival rate of 264 CML patients treated with TKIs (median age 58 years old) was 89.6% [95% confidence interval (CI), 84.9-92.9%], and 80.5% (95% CI, 73.4-85.9%) at 5 and 10 years after the CML diagnosis, respectively. CVD events occurred in 26 patients (9.8%, median age 67.5 years old) with a median 65.5 months of TKI treatment. The cumulative incidences at 2 and 5 years was 2.4% (95% CI, 1.0-4.8%) and 5.2% (95% CI, 2.8-8.6%), respectively. Hypertension and a high SCORE chart risk at the diagnosis of CML were associated with CVD events during TKI treatment. Conclusion TKI treatment contributed to the long-term survival of CML patients in Nagasaki Prefecture in a "real-world" setting, but the incidence of CVDs seemed to be increased in these patients. A proper approach to managing risk factors for CVD is warranted to reduce CVD events during TKI treatment.

No clear survival benefit of azacitidine for lower-risk myelodysplastic syndromes: A retrospective study of Nagasaki

The efficacy of azacitidine (AZA) on survival of lower risk (LR) - myelodysplastic syndromes (MDS) is controversial. To address this issue, we retrospectively evaluated the long-term survival benefit of AZA for patients with LR-MDS defined by International Prognostic Scoring System (IPSS). Using data from 489 patients with LR-MDS in Nagasaki, hematologic responses according to International Working Group 2006 and overall survival (OS) were compared among patients that received best supportive care (BSC), immunosuppressive therapy (IST), erythropoiesis-stimulating agents (ESA), and AZA. Patients treated with AZA showed complete remission (CR) rate at 11.3%, marrow CR at 1.9%, and any hematologic improvement at 34.0%, with transfusion independence (TI) of red blood cells in 27.3% of patients. and platelet in 20% of patients, respectively. Median OS for patients received IST, ESA, BSC, and AZA (not reached, 91 months, 58 months, and 29 months, respectively) differed significantly (P < .001). Infection-related severe adverse events were observed in more than 20% of patients treated with AZA. Multivariate analysis showed age, sex, IPSS score at diagnosis, and transfusion dependence were significant for OS, but AZA treatment was not, which maintained even response to AZA, and IPSS risk status at AZA administration was added as factors. We could not find significant survival benefit of AZA treatment for LR-MDS patients.

Prognostic analysis of chronic myeloid leukemia in Chinese population in an imatinib era

We evaluated the outcomes of chronic myeloid leukemia (CML) patients receiving imatinib treatment in chronic (CP), accelerated (AP), and blast crisis (BP) phases. The single-institution treatment experiences of Chinese patients with CML were presented. A total of 275 CML patients (CP, 210; AP, 24; and BP, 41) who received imatinib between February 2001 and April 2008 were enrolled in this study. We evaluated the treatment responses (hematologic, cytogenetic, and molecular), overall survival (OS), event-free survival (EFS), and prognostic factors of outcome. At the cut-off point, the complete cytogenetic response (CCyR) and complete molecular response rates of patients in the CP were 84.7% and 61.9%, respectively, which were significantly higher than those of patients in the AP (50% and 29.1%, respectively, both P < 0.001) and BP (24.3% and 9.7%, respectively, both P < 0.001). The estimated five-year OS and five-year EFS rates were 93.2% and 86.4% for CP patients, as well as 64.5% and 50.9% for AP patients, which were significantly higher than those for BP patients (P < 0.001). In CP patients, univariate analysis revealed that early treatment with imatinib, achieving CCyR within 12 months, additional cytogenetic abnormalities, and kinase domain mutations were associated with the treatment outcome. More patients are needed to carry out multivariate analysis.

Imatinib for newly diagnosed chronic-phase chronic myeloid leukemia: results of a prospective study in Japan

Although imatinib has become the current standard treatment for chronic myeloid leukemia (CML), there is limited information regarding its efficacy and safety among Japanese patients. We therefore conducted a prospective multi-center open-label study of imatinib for Japanese patients with newly diagnosed chronic-phase CML (CP-CML). A total of 107 patients were enrolled and treated with imatinib at an initial daily dose of 400 mg. Eighty-three patients completed 3 years of study treatment. The cumulative rates of major cytogenetic response and complete cytogenetic response (CCyR) were 90.9 and 90.2% at 3 years, respectively. The safety profile was not very different from that reported in the IRIS study, although grade > or =3 neutropenia occurred relatively frequently (31.8 vs. 14.3%). Only seven patients discontinued the study due to adverse events, as did four patients due to insufficient efficacy. The 3-year probabilities of overall survival and progression-free survival were 93.2 and 91.4%, respectively. Higher average daily doses (i.e., > or =350 mg) were significantly associated not only with higher rates of achieving CCyR, but also with longer duration of CCyR. These findings confirm the clinical utility of imatinib in Japanese patients with newly diagnosed CP-CML, and suggest detrimental effect of low average daily dose on treatment results.

Comparison of the cytogenetic and molecular analyses in the assessment of imatinib response in chronic myelocytic leukemia

We aimed to compare the cytogenetic and molecular analyses in the assessment of imatinib mesylate response in patients suffering the chronic phase of chronic myelocytic leukemia who were refractory to alpha-interferon treatment. A total of 117 patients in the chronic phase of chronic myelocytic leukemia were included. The patients were treated with 400 mg/day imatinib mesylate. Bone marrow samples were obtained for the cytogenetic and molecular analyses. Patients without the Ph chromosome were defined as complete cytogenetic responders. Partial cytogenetic response was determined when the Ph chromosome was detected in 1-35% of the cells. Molecular response was determined by quantitative real-time reverse transcriptase polymerase chain reaction (QR-PCR) and defined as no detection of BCR-ABL mRNA. The frequencies of complete and partial cytogenetic response were 29% (n = 34) and 15% (n = 18), respectively. No cytogenetic response was achieved in 56% (n = 65) of the patients. Molecular response was achieved in 62% (n = 21) and 33% (n = 6) of the complete and partial cytogenetic responders, respectively. All of the 65 patients with no cytogenetic response were also molecular nonresponders. We conclude that there is reasonable agreement between the cytogenetic and molecular analyses. Both methods are complementary in the assessment of response to therapy.

High-resolution melting analysis for a reliable and two-step scanning of mutations in the tyrosine kinase domain of the chimerical bcr-abl gene

For relevant imatinib therapy against Philadelphia (Ph)-positive leukemias, it is essential to monitor mutations in the chimerical bcr-abl tyrosine kinase domain (TKD). However, there is no universally acceptable consensus on how to efficiently identify mutations in the target TKD. Recently, high-resolution melting (HRM) technology was developed, which allows gene scanning using an inexpensive generic heteroduplex-detecting dsDNA-binding dye. This study aimed to validate the introduction of HRM in a practical clinical setting for screening of mutations in sporadic sites of the chimerical bcr-abl TKD. All chimerical and wild-type abl TKD regions selectively amplified were used for HRM assays and direct sequencing. The HRM test had approximately 5-90% detection sensitivity for mutations. In contrast to mixture samples with mutant and wild-type cells, all mutant cell samples had indeterminate melting curves equivalent to those of the wild-type due to formation of only a homodulex. This issue was improved by the addition of exogenous wild-type DNA after PCR. Subsequently, HRM results gave a high accordance rate of 97.8% (44/45 samples) compared to the sequencing data. The discordant results in one appear to be due to unsuccessful amplification. Thus, HRM may be considered to be suitable for reliable scanning of mutations in the chimerical abl TKD in a clinical setting.

Long-term efficacy of imatinib in a practical setting is correlated with imatinib trough concentration that is influenced by body size: a report by the Nagasaki CML Study Group

Imatinib has dramatically improved long-term survival of chronic myelogenous leukemia (CML) patients. To analyze its efficacy in a practical setting, we registered most of CML patients in Nagasaki Prefecture of Japan. Of these, 73 patients received imatinib as an initial therapy. The overall survival rate of these patients was 88.7% at 6 years, and the cumulative complete cytogenetic response rate was 82.5% at 18 months. These results are comparable with the data of other reports including the IRIS study; however, the administered imatinib dose was smaller in our study than that in other reports. To address these discrepancies, we measured the trough concentration of imatinib among 35 patients. Although 39% of the patients were administered less than 400 mg/day, the trough level was comparable to those of previous reports. The trough level of imatinib showed a significant relationship with its efficacy, and was clearly related to dose of imatinib administrated and dose of imatinib divided by body surface area (BSA). Considering the smaller BSA of Japanese patients as compared to those of foreign origin, the results suggest that a lower dose of imatinib could maintain enough trough level and provided excellent results for the treatment of CML in our registry.

Phase 1/2 clinical study of dasatinib in Japanese patients with chronic myeloid leukemia or Philadelphia chromosome-positive acute lymphoblastic leukemia

A phase 1/2 study was conducted to assess the safety and efficacy of dasatinib in Japanese patients with chronic myelogenous leukemia (CML) or Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph(+) ALL) resistant or intolerant to imatinib. In phase 1, 18 patients with chronic phase (CP) CML were treated with dasatinib 50, 70, or 90 mg twice daily to evaluate safety. Dasatinib <or= 90 mg twice daily was well tolerated. In phase 2, dasatinib 70 mg was given twice daily to CP-CML patients for 24 weeks and to CML patients in accelerated phase (AP)/blast crisis (BC) or Ph(+) ALL for 12 weeks. In the CP-CML group (n = 30) complete hematologic response was 90% and major cytogenetic response (MCyR) 53%. In the AP/BC-CML group (n = 11) major hematologic response (MaHR) was 64% and MCyR 27%, whereas in the Ph(+) ALL group (n = 13) MaHR was 38% and MCyR 54%. Dasatinib was well tolerated and most of the nonhematologic toxicities were mild or moderate. Dasatinib therapy resulted in high rates of hematologic and cytogenetic response, suggesting that dasatinib is promising as a new treatment for Japanese CML and Ph(+) ALL patients resistant or intolerant to imatinib.

Influence of late treatment on how chronic myeloid leukemia responds to imatinib

INTRODUCTION

In Brazil, patients with chronic myeloid leukemia (CML) in the chronic phase were not given first-line imatinib treatment until 2008. Therefore, there was a long period of time between diagnosis and the initiation of imatinib therapy for many patients. This study aims to compare the major molecular remission (MMR) rates of early versus late imatinib therapy in chronic phase CML patients.

METHODS

Between May 2002 and November 2007, 44 patients with chronic phase CML were treated with second-line imatinib therapy at the Hematology Unit of the Ophir Loyola Hospital (Belém, Pará, Brazil). BCR-ABL transcript levels were measured at approximately six-month intervals using quantitative polymerase chain reaction.

RESULTS

The early treatment group presented a 60% probability of achieving MMR, while the probability for those patients who received late treatment was 40%. The probability of either not achieving MMR within one year of the initiation of imatinib therapy or losing MMR was higher in patients who received late treatment (79%), compared with patients who received early treatment (21%, odds ratio=5.75, P=0.012). The probability of maintaining MMR at 30 months of treatment was 80% in the early treatment group and 44% in the late treatment group (P=0.0005).

CONCLUSIONS

For CML patients in the chronic phase who were treated with second-line imatinib therapy, the probability of achieving and maintaining MMR was higher in patients who received early treatment compared with those patients for whom the time interval between diagnosis and initiation of imatinib therapy was longer than one year.