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Background: Although the development of BCR::ABL1 tyrosine kinase inhibitors (TKIs) rendered chronic myeloid leukemia (CML) a manageable condition, acquisition of drug resistance during blast phase (BP) progression remains a critical challenge. Here, we reposition FLT3, one of the most frequently mutated drivers of acute myeloid leukemia (AML), as a prognostic marker and therapeutic target of BP-CML. Methods: We generated FLT3 expressing BCR::ABL1 TKI-resistant CML cells and enrolled phase-specific CML patient cohort to obtain unpaired and paired serial specimens and verify the role of FLT3 signaling in BP-CML patients. We performed multi-omics approaches in animal and patient studies to demonstrate the clinical feasibility of FLT3 as a viable target of BP-CML by establishing the (1) molecular mechanisms of FLT3-driven drug resistance, (2) diagnostic methods of FLT3 protein expression and localization, (3) association between FLT3 signaling and CML prognosis, and (4) therapeutic strategies to tackle FLT3+ CML patients. Results: We reposition the significance of FLT3 in the acquisition of drug resistance in BP-CML, thereby, newly classify a FLT3+ BP-CML subgroup. Mechanistically, FLT3 expression in CML cells activated the FLT3-JAK-STAT3-TAZ-TEAD-CD36 signaling pathway, which conferred resistance to a wide range of BCR::ABL1 TKIs that was independent of recurrent BCR::ABL1 mutations. Notably, FLT3+ BP-CML patients had significantly less favorable prognosis than FLT3− patients. Remarkably, we demonstrate that repurposing FLT3 inhibitors combined with BCR::ABL1 targeted therapies or the single treatment with ponatinib alone can overcome drug resistance and promote BP-CML cell death in patient-derived FLT3+ BCR::ABL1 cells and mouse xenograft models. Conclusion: Here, we reposition FLT3 as a critical determinant of CML progression via FLT3-JAK-STAT3-TAZ-TEAD-CD36 signaling pathway that promotes TKI resistance and predicts worse prognosis in BP-CML patients. Our findings open novel therapeutic opportunities that exploit the undescribed link between distinct types of malignancies. [ABSTRACT FROM AUTHOR]

Cobll1 affects blast crisis (BC) progression and tyrosine kinase inhibitor (TKI) resistance in chronic myeloid leukemia (CML). PACSIN2, a novel Cobll1 binding protein, activates TKI‐induced apoptosis in K562 cells, and this activation is suppressed by Cobll1 through the interaction between PACSIN2 and Cobll1. PACSIN2 also binds and inhibits SH3BP1 which activates the downstream Rac1 pathway and induces TKI resistance. PACSIN2 competitively interacts with Cobll1 or SH3BP1 with a higher affinity for Cobll1. Cobll1 preferentially binds to PACSIN2, releasing SH3BP1 to promote the SH3BP1/Rac1 pathway and suppress TKI‐mediated apoptosis and eventually leading to TKI resistance. Similar interactions among Cobll1, PACSIN2, and SH3BP1 control hematopoiesis during vertebrate embryogenesis. Clinical analysis showed that most patients with CML have Cobll1 and SH3BP1 expression at the BC phase and BC patients with Cobll1 and SH3BP1 expression showed severe progression with a higher blast percentage than those without any Cobll1, PACSIN2, or SH3BP1 expression. Our study details the molecular mechanism of the Cobll1/PACSIN2/SH3BP1 pathway in regulating drug resistance and BC progression in CML. [ABSTRACT FROM AUTHOR]

Background: We investigated the feasibility of the clinical application of non‐invasive transthoracic echocardiography for diagnosis of pulmonary arterial hypertension induced by dasatinib (D‐PAH) in chronic myeloid leukemia (CML). Methods: A total of 451 CML patients who were examined by 2D‐echocardiography at least once at baseline and/or during dasatinib therapy as frontline (n = 196) and subsequent line (n = 255) therapies were included in this study. D‐PAH was defined as right ventricular systolic pressure (RVSP) >40 mm Hg with relevant symptoms and the absence of other specific etiologies. Results: A total of 847 echocardiographies were performed including at baseline (n = 255) and during dasatinib treatment (n = 592). During the median of 36.2 (0.1–181.8) months of dasatinib therapy, the level of RVSP gradually increased (Spearman's r = 0.2819, p < 0.001) and the mean RVSP was significantly increased after taking dasatinib therapy compared with baseline. During dasatinib therapy, 56 (12.4%) patients had RVSP >40 mm Hg without (asymptomatic, n = 27, 48.2%) or with symptoms (D‐PAH, n = 29, 51.8%). All asymptomatic patients maintained dasatinib therapy without further symptoms and the D‐PAH patients ultimately switched to other tyrosine kinase inhibitors. After dasatinib discontinuation, 13 (45%) and 15 (52%) patients showed RVSP normalization and gradual decrease, respectively. Conclusions: Our large cohort study demonstrated that the gradual increment of RVSP might be induced by dasatinib and non‐invasive echocardiography can be fast way for early diagnosis as well as for monitoring of D‐PAH. [ABSTRACT FROM AUTHOR]

What is known and objective: Dried blood spot (DBS) sampling is a minimally invasive method of blood sampling that enables monitoring of drug concentrations to be more convenient. This study aimed at developing a DBS sampling method for an accurate and precise prediction of radotinib plasma concentrations (Cp) in patients with chronic myeloid leukaemia (CML). Methods: Dried blood spot and venous blood samples were simultaneously collected from fifty CML patients who had been receiving radotinib for at least a week. Radotinib concentrations were measured using a high‐performance liquid chromatographic method with tandem mass spectrometric detection. Unmeasured Cp was predicted directly based on a Deming regression between DBS concentrations (CDBS) and Cp. Unmeasured Cp was also predicted from CDBS corrected by each patient's haematocrit (Hct). Both prediction methods were evaluated for their accuracy and precision using Deming regression and Bland‐Altman analysis. Results and discussion: The Deming regression equation between CDBS and Cp was obtained as follows: Cp = 1.34∙CDBS + 4.26 (r2 =.97). Cp was directly predictable using Cp,pred1 = 1.34∙CDBS + 4.26. With Hct correction, Cp was alternatively predictable using Cp,pred2 = CDBS/ (1–Hct + Hct2). The slopes of Deming regression line between predicted and measured Cp were 0.99 and 1.02 for the direct and Hct‐corrected method, respectively. The mean biases (accuracy) were −0.44% and 1.6% with the 95% limits of agreement (precision) of −22.4% to 21.5% and −20.5% to 23.7%, respectively. More than 93% of predicted and measured Cp pairs had their differences within 20% of the mean of each pair in both methods. What is new and conclusions: Radotinib CDBS are highly correlated with radotinib Cp. Radotinib Cp can be accurately and precisely predicted from CDBS using direct or Hct‐corrected prediction methods. Both appear to be appropriate for the therapeutic monitoring of radotinib in patients with CML. [ABSTRACT FROM AUTHOR]

Introduction: Nilotinib is a BCR-ABL tyrosine kinase inhibitor approved for chronic myeloid leukemia. We present a case of severe immune-mediated liver injury by nilotinib treatment. Case report: A 59-year-old woman was referred to the liver clinic because of elevated liver enzyme levels. One year prior, she was diagnosed as having chronic myeloid leukemia and treated with nilotinib therapy. The level of aspartate aminotransferase and alanine aminotransferase were 578 IU/L and 499 IU/L, respectively. Percutaneous needle liver biopsy showed extensive centrilobular infiltration of immune cells and destruction of the lobular architecture with minimal inflammation in the portal triad. Immunohistochemical staining showed that many CD8+ T cells and CD56+ cells infiltrated the site of inflammation. Multicolor fluorescence-activated cell-sorting analysis revealed that a considerable number of intrahepatic CD8+ T cells showed an activated phenotype compared with the healthy control. She was diagnosed with nilotinib-induced, immune-mediated liver injury. Prednisolone treatment (30 mg daily) was started and caused rapid normalization of liver enzyme levels. Conclusion: Nilotinib can cause immune-mediated liver injury. The use of corticosteroid can be treatment option in immune-mediated liver injury. [ABSTRACT FROM AUTHOR]

Background: Chronic myeloid leukemia (CML) pathogenesis is mainly driven by the oncogenic breakpoint cluster region-Abelson murine leukemia viral oncogene homolog 1 (BCR-ABL) fusion protein. Since BCR-ABL displays abnormal constitutive tyrosine kinase activity, therapies using tyrosine kinase inhibitors (TKis) such as imatinib represent a major breakthrough for the outcome of CML patients. Nevertheless, the development of TKi resistance and the persistence of leukemia stem cells (LSCs) remain barriers to cure the disease, justifying the development of novel therapeutic approaches. Since the activity of histone deacetylase (HDAC) is deregulated in numerous cancers including CML, pan-HDAC inhibitors may represent promising therapeutic regimens for the treatment of CML cells in combination with TKi. Results: We assessed the anti-leukemic activity of a novel hydroxamate-based pan-HDAC inhibitor MAKV-8, which complied with the Lipinski's "rule of five," in various CML cells alone or in combination with imatinib. We validated the in vitro HDAC-inhibitory potential of MAKV-8 and demonstrated efficient binding to the ligand-binding pocket of HDAC isoenzymes. In cellulo, MAKV-8 significantly induced target protein acetylation, displayed cytostatic and cytotoxic properties, and triggered concomitant ER stress/protective autophagy leading to canonical caspase-dependent apoptosis. Considering the specific upregulation of selected HDACs in LSCs from CML patients, we investigated the differential toxicity of a co-treatment with MAKV-8 and imatinib in CML versus healthy cells. We also showed that beclin-1 knockdown prevented MAKV-8-imatinib combination-induced apoptosis. Moreover, MAKV-8 and imatinib co-treatment synergistically reduced BCR-ABL-related signaling pathways involved in CML cell growth and survival. Since our results showed that LSCs from CML patients overexpressed c-MYC, importantly MAKV-8-imatinib co-treatment reduced c-MYC levels and the LSC population. In vivo, tumor growth of xenografted K-562 cells in zebrafish was completely abrogated upon combined treatment with MAKV-8 and imatinib. Conclusions: Collectively, the present findings show that combinations HDAC inhibitor-imatinib are likely to overcome drug resistance in CML pathology. [ABSTRACT FROM AUTHOR]

Summary: In the phase 3 study RERISE, patients with newly diagnosed chronic myeloid leukaemia in chronic phase demonstrated significantly faster and higher rates of major molecular response (MMR) with twice‐daily radotinib 300 mg (n = 79) or 400 mg (n = 81) than with once‐daily imatinib 400 mg (n = 81) after 12 months. With ≥48 months' follow‐up, MMR was higher with radotinib 300 mg (86%) or 400 mg (83%) than with imatinib (75%). Among patients with BCR‐ABL1 ≤ 10% at three months, MMR and molecular response 4·5 (MR4·5) were achieved within 48 months by more radotinib‐treated patients (300 mg: 84% and 52%, respectively; 400 mg: 74% and 44%, respectively) than imatinib‐treated patients (71% and 44%, respectively). Estimated overall and progression‐free survival rates at 48 months were not significantly different between imatinib (94% and 94%, respectively) and radotinib 300 mg (99% and 97%, respectively) or 400 mg (95% and 93%, respectively). The treatment failure rate was significantly higher with imatinib (19%) than with radotinib 300 mg (6%; P = 0·0197) or 400 mg (5%; P = 0·0072). Safety profiles were consistent with previous reports; most adverse events occurred within 12 months. Radotinib continues to demonstrate robust, deep molecular responses, suggesting that treatment‐free remission may be attainable. [ABSTRACT FROM AUTHOR]

The present study aimed to assess the clinical impact of BCR‐ABL1 transcript levels determined at an earlier time point than the 3‐month early molecular response (EMR) in chronic‐phase chronic myeloid leukemia (CML‐CP) patients. BCR‐ABL1 transcript levels of CML‐CP patients (n = 258; median age, 43 [range, 18‐81] years) treated with various tyrosine kinase inhibitors (TKIs) were determined at 4 weeks (28 ± 3 days) and at every 3 months of treatment initiation. At 4 weeks, receiver operating characteristic curves revealed that cutoff values of BCR‐ABL1 transcripts for achieving major molecular responses (MMRs) by 12 and 60 months were 40.89% and 39.16%, respectively (95% CI, 0.658‐0.772 and 95% CI, 0.643‐0.758; P < 0.0001). With 40% of BCR‐ABL1 transcripts at 4 weeks (very early MR; VEMR), patients with VEMR achieved higher 3‐month EMR and 4‐week VEMR significantly associated with higher cumulative incidences of 5‐year MMR (89.1% vs 72.3%; P < 0.001) and 5‐year deep molecular response (DMR) (56.5% vs 29.4%; P = 0.001). Furthermore, event‐free survival (EFS)‐a (93.0% vs 84.8%; P = 0.068) and EFS‐b (71.1% vs 57.9%; P = 0.061) by 5 years were also marginally significant. VEMR and 3‐month EMR were achieved in 89 patients, with significantly superior outcomes. In multivariate analyses, lower leukocyte count (P = 0.008) and frontline second‐generation TKI therapy size (P < 0.001) were significantly associated with VEMR achievement, but not baseline BCR‐ABL1 level and CML duration. In conclusion, the 4‐week BCR‐ABL1 transcript levels including VEMR could be important to predict long‐term outcomes and may provide additional information about innate intrinsic sensitivity to CML among individuals. The very early molecular response assessment could be important to predict long‐term outcomes and may provide additional information about innate intrinsic sensitivity to individual CML clone. As it also allows for the prediction of DMR, VEMR can be used as one of the important tools to select candidates for treatment‐free remission. [ABSTRACT FROM AUTHOR]

Chronic, low-grade adverse events are common in patients with chronic myeloid leukemia who are treated with imatinib. These events may decrease patient quality of life and adherence, and may ultimately contribute to a suboptimal response. Alternative, second-generation tyrosine kinase inhibitors, such as dasatinib, are available with the potential to reduce adverse events, improve tolerability, and support long-term treatment goals. We present the final, primary analysis of DASPERSE/CA180-400 (NCT01660906), an open-label, multicenter, phase IV study designed to determine whether chronic, low-grade nonhematologic adverse events in imatinib-treated patients improve after switching to dasatinib, without affecting efficacy. Of the 121 chronic, grade 1/2, imatinib-related adverse events identified at baseline in 39 patients, 77% resolved or improved within 3 months after switching to dasatinib. Dasatinib maintained a consistent safety profile; headache (33%), pleural effusion (26%), fatigue (23%), and rash (23%) were the most common treatment-related adverse events after the switch. Patients either maintained (56%) or improved (44%) their molecular response on dasatinib. Patients who switched to dasatinib also experienced improved patient-reported symptom burden from baseline as assessed by the MD Anderson Symptom Inventory for chronic myeloid leukemia (on a 1-10 scale, mean change in disease-specific score was - 2.24 and core symptom severity score was - 1.06). Overall, the efficacy and quality of life/symptom burden improved in many patients, despite the onset of dasatinib-related adverse events in most patients. This suggests that imatinib-treated patients with chronic, low-grade adverse events could benefit from switching to treatment with dasatinib. [ABSTRACT FROM AUTHOR]

Abstract: Radotinib is a second‐generation BCR‐ABL1 tyrosine kinase inhibitor approved for the treatment of chronic myeloid leukemia in chronic phase (CP‐CML). Here, using the data from a Phase 3 study conducted in patients with newly diagnosed CP‐CML, the dose–efficacy as well as dose–safety relationship analyses were performed to determine a safe and effective initial dosage regimen of radotinib. A significant positive association was detected between the starting dose of radotinib adjusted for body weight (Dose/BW) and the probability of dose‐limiting toxicity (≥grade 3 hematologic and nonhematologic toxicity) (P = 0.003). In contrast, a significant inverse association was discovered between Dose/BW and the probability of major molecular response (BCR‐ABL1/ABL1 ≤ 0.1%) when controlled for sex (P = 0.033). Moreover, frequent dose interruptions and reductions secondary to radotinib toxicities occurred in the Phase 3 study, resulting in nearly half (44%) of patients receiving a reduced dose at a 12‐month follow‐up. In conclusion, the results of this study demonstrate the need for initial radotinib dose attenuation to improve the long‐term efficacy and safety of radotinib. Hence, the authors suggest a new upfront radotinib dose of 400 mg once daily be tested in patients with newly diagnosed CP‐CML. [ABSTRACT FROM AUTHOR]

We conducted this study to identify the factors for predicting poor outcomes in chronic myeloid leukemia patients who failed to achieve a 3-month early molecular response (EMR). Of the 413 newly diagnosed, chronic phase, chronic myeloid leukemia patients receiving imatinib (IM), 120 (29.1%) failed to achieve a 3-month EMR. With a median follow-up of 67.0 months, 39 patients continued IM treatment with at least complete cytogenetic response (CCyR), and 81 patients permanently discontinued IM treatment. The cumulative incidence rates of CCyR and major molecular response (MMR) by 3 years were 90.1 ± 3.9% and 53.7 ± 7.3%, respectively. After adjusting for potential factors, multivariate analyses showed that a transcript type of e13a2, compared with e14a2, and a larger spleen size were independent factors for failure of overall MMR. The predictive factors outlined in this study may provide valuable information for high-risk patients who would benefit from early decision-making regarding therapy change. [ABSTRACT FROM AUTHOR]

The article presents a case study involving a 35-year-old male with chronic myeloid leukemia, who started treatment with 800 mg of radotinib in 2013. The patient experienced an increase in the number of pigmented lesions over one year, with an atypical pigmented macule, among them, on his face showing a 5-mm-sized flat surface and asymmetric irregular borders with variable pigmentation.

Background: Effective treatment options for patients with chronic myeloid leukemia (CML) or Philadelphia-positive (Ph+) acute lymphoblastic leukemia (ALL) who have the threonine to isoleucine mutation at codon 315 (T315I) are few. The objective of this study was to compare overall survival (OS) between patients with CML and those with Ph+ ALL who received treatment with ponatinib versus allogeneic stem cell transplantation (allo-SCT).Methods: A post hoc, retrospective, indirect comparison of OS among patients who received single-agent ponatinib in the Ponatinib Ph+ ALL and CML Evaluation (PACE) trial with those who underwent allo-SCT as reported to the European Bone Marrow Transplant registry, stratified by CML disease phase and Ph+ ALL, was conducted. Kaplan-Meier survival curves and multivariate Cox proportional-hazards models were used to compare OS between intervention groups, adjusting for time from diagnosis to intervention, age, sex, and geographic region; 24-month and 48-month OS rates and median OS were reported.Results: After adjustment for potential confounders, 24-month and 48-month OS rates were significantly higher in patients with chronic-phase CML (CP-CML) who received ponatinib compared with those who underwent allo-SCT (24 months: 84% vs 60.5%, respectively; P = .004; 48 months: 72.7% vs 55.8%, respectively; P = .013), with a hazard ratio (HR) of 0.37 (95% confidence interval [CI], 0.16-0.84; P = .017). In patients who had accelerated-phase CML, OS rates were not significantly different between the groups (HR, 0.90; 95% CI, 0.20-4.10; P = .889). In patients who had blast-crisis CML and those with Ph+ ALL, ponatinib was associated with shorter OS compared with allo-SCT (blast-crisis CML: HR, 2.29 [95% CI, 1.08-4.82; P = .030]; Ph+ ALL: HR, 2.77 [95% CI, 0.73-10.56; P = .146]).Conclusions: Although allo-SCT remains an important treatment option for patients with T315I-positive advanced CML and Ph+ ALL, ponatinib represents a valuable alternative for patients with T315I-positive CP-CML. Cancer 2017;123:2875-80. © 2017 American Cancer Society. [ABSTRACT FROM AUTHOR]

Asian patients with chronic myeloid leukemia (CML) tend to have different characteristics compared with patients from other regions, including younger age and smaller body size. The phase 3, open-label, randomized DASISION trial (NCT00481247), comparing dasatinib 100 mg once daily (QD) ( n = 259) with imatinib 400 mg QD ( n = 260) in newly diagnosed chronic phase CML (CML-CP), included a sizeable East Asian population ( n = 60: dasatinib; n = 48: imatinib). In East Asian patients, dasatinib showed favorable 24-month rates of major molecular response (68% vs. 50% for imatinib) and complete cytogenetic response (92% vs. 88%), and more patients achieved BCR-ABL1 transcript levels ≤ 10% at 3 months with dasatinib (91% vs. 69%), similar to the overall population. Relative to non-East Asian patients, the incidence of rash, fluid-related events and grade 3/4 neutropenia and thrombocytopenia appeared to be higher in East Asians, regardless of treatment. Pharmacokinetic analysis revealed statistically non-significant increased dasatinib exposure among East Asian patients. Results support the use of dasatinib 100 mg QD as first-line CML treatment in both East Asian and non-East Asian patients. [ABSTRACT FROM AUTHOR]

The aim of this study was to estimate the prognostic factors for the outcomes of chronic myeloid leukemia (CML) patients receiving allogeneic stem cell transplantation (SCT) in chronic phase (CP) in the era of tyrosine kinase inhibitors (TKIs). Ninety-seven patients who underwent allogeneic SCT in CP were analyzed. Forty-seven were TKI-naïve at the time of transplant, and 50 received TKI(s) treatment before transplantation. After a median follow-up of 115.8 months, the 4-year overall survival and event-free survival were 80.4 and 58.8%, respectively. Multivariate analysis showed that there were no differences in survival outcomes based on prior TKI therapy. Older age was a prognostic factor for higher treatment-related mortality (TRM), and the type of graft source and younger age were associated with relapse, but prior TKI therapy and disease status at the time of transplant were not associated with either TRM or relapse. Additionally, a major molecular response at 1 month and an MR4.5 at 3 months were important predictors of favorable long-term outcomes. This study demonstrates the prognostic factors for the outcomes of allogeneic SCT in CP CML and shows that survival outcomes were not affected by the administration of long-term multi-TKI treatment prior to transplantation. [ABSTRACT FROM AUTHOR]

Atypical chronic myeloid leukemia (aCML) shares clinical and laboratory features with CML, but it lacks the BCR-ABL1 fusion. We performed exome sequencing of eight aCMLs and identified somatic alterations of SETBP1 (encoding a p.Gly870Ser alteration) in two cases. Targeted resequencing of 70 aCMLs, 574 diverse hematological malignancies and 344 cancer cell lines identified SETBP1 mutations in 24 cases, including 17 of 70 aCMLs (24.3%; 95% confidence interval (CI) = 16-35%). Most mutations (92%) were located between codons 858 and 871 and were identical to changes seen in individuals with Schinzel-Giedion syndrome. Individuals with mutations had higher white blood cell counts (P = 0.008) and worse prognosis (P = 0.01). The p.Gly870Ser alteration abrogated a site for ubiquitination, and cells exogenously expressing this mutant exhibited higher amounts of SETBP1 and SET protein, lower PP2A activity and higher proliferation rates relative to those expressing the wild-type protein. In summary, mutated SETBP1 represents a newly discovered oncogene present in aCML and closely related diseases. [ABSTRACT FROM AUTHOR]

Undetectable BCR--ABL transcripts in patients with chronic myeloid leukemia (CML) should not be regarded as indicative of a cure, due to the sensitivity limit of current real-time quantitative polymerase chain reaction (RQ-PCR) technology. To demonstrate the feasibility of more sensitive approaches, 62 samples from 43 patients with CML were screened by conventional RQ-PCR, replicate RQ-PCR (rRQ-PCR), and/or nanofluidic digital PCR (dPCR). First, we confirmed the correlation of dPCR to conventional RQ-PCR using 30 patient samples with various minimal residual disease (MRD) levels. When the sensitivity limits were determined using cell line and patient sample dilutions, rRQ-PCR and dPCR with pre-amplification showed 2--3 log improvement compared to conventional RQ-PCR, and 24 of 32 PCR negative samples as assayed by conventional RQ-PCR showed detectable BCR--ABL in rRQ-PCR and/or dPCR. More important, using dPCR in conjunction with a pre-amplification step, a continuous decline in MRD level could be precisely monitored even after it became undetectable by conventional RQ-PCR. In this study, both rRQ-PCR and dPCR demonstrated successful detection of BCR--ABL transcripts not detectable in conventional RQ-PCR, and these data show the potential feasibility of highly sensitive PCR approaches for molecular monitoring and clinical relevance in future CML management by allowing further characterization of patients who achieve PCR negativity in a conventional RQ-PCR assay. [ABSTRACT FROM AUTHOR]

Abstract: Chronic myeloid leukemia (CML) management varies across Asia due to disparities in affluence and healthcare provision. We surveyed CML management practice at 33 hospitals in 14 countries/regions to identify treatment challenges and opportunities for harmonization. Patients were generally treated according to international guidelines; however, tyrosine kinase inhibitors (TKIs) and molecular monitoring are inaccessible to many patients not covered by national insurance or eligible for subsidized treatment. Late diagnosis and suboptimal monitoring, often due to cost and accessibility issues, are challenges. Priorities for Asia include: extending accessibility to TKIs; specialist laboratory monitoring; and enriching data to support regional CML management guidelines. [ABSTRACT FROM AUTHOR]

Background: Nilotinib has been shown to be a more potent inhibitor of BCR-ABL than imatinib. We evaluated the efficacy and safety of nilotinib, as compared with imatinib, in patients with newly diagnosed Philadelphia chromosome–positive chronic myeloid leukemia (CML) in the chronic phase. Methods: In this phase 3, randomized, open-label, multicenter study, we assigned 846 patients with chronic-phase Philadelphia chromosome–positive CML in a 1:1:1 ratio to receive nilotinib (at a dose of either 300 mg or 400 mg twice daily) or imatinib (at a dose of 400 mg once daily). The primary end point was the rate of major molecular response at 12 months. Results: At 12 months, the rates of major molecular response for nilotinib (44% for the 300-mg dose and 43% for the 400-mg dose) were nearly twice that for imatinib (22%) (P<0.001 for both comparisons). The rates of complete cytogenetic response by 12 months were significantly higher for nilotinib (80% for the 300-mg dose and 78% for the 400-mg dose) than for imatinib (65%) (P<0.001 for both comparisons). Patients receiving either the 300-mg dose or the 400-mg dose of nilotinib twice daily had a significant improvement in the time to progression to the accelerated phase or blast crisis, as compared with those receiving imatinib (P=0.01 and P=0.004, respectively). No patient with progression to the accelerated phase or blast crisis had a major molecular response. Gastrointestinal and fluid-retention events were more frequent among patients receiving imatinib, whereas dermatologic events and headache were more frequent in those receiving nilotinib. Discontinuations due to aminotransferase and bilirubin elevations were low in all three study groups. Conclusions: Nilotinib at a dose of either 300 mg or 400 mg twice daily was superior to imatinib in patients with newly diagnosed chronic-phase Philadelphia chromosome–positive CML. (ClinicalTrials.gov number, NCT00471497.) N Engl J Med 2010;362:2251-9. [ABSTRACT FROM AUTHOR]

Abstract: Sequential treatment with different tyrosine kinase inhibitors (TKIs) is one of the strategies for handling chronic myeloid leukemia (CML) in which dynamic change in Bcr-Abl kinase domain mutation is often an obstacle faced during TKI therapy. Here we report successful sequential therapy with different TKIs for the CML patient harboring V299L and E459K compound mutations. Molecular monitoring including quantitative analysis of BCR-ABL transcript level and mutation analysis were performed regularly for successful treatment. Additionally a drug-target complex was structurally modeled to investigate influence of amino acid substitutions on drug resistance, and to choose alternative TKI in sequential therapy, suggesting protein structural modeling can be useful approach in selecting alternative TKIs. [Copyright &y& Elsevier]

Although imatinib is considered as a front line therapy in patients with chronic myeloid leukemia (CML), it is still unclear whether transient imatinib discontinuation may adversely affect the outcome. This study was conducted to investigate long-term outcome after discontinuation and resumption of imatinib, and to determine whether intermittent imatinib therapy can be employed in patients with CML. Twenty six Philadelphia chromosome positive (Ph+) patients with CML discontinued imatinib when they achieved complete cytogenetic response (CCyR) or complete molecular response (CMR), and they were retreated with imatinib in case of hematologic, cytogenetic or molecular relapse. Except one patient who progressed and two patients who are in persistent molecular remission without imatinib resumption, all of 23 patients are maintaining the best response achieved after imatinib resumption with a median follow-up of 44 months. This study shows that although imatinib cannot be discontinued completely, intermittent therapy can be considered for the treatment of patients with CML in particular situations. [ABSTRACT FROM AUTHOR]

The detection of the Philadelphia (Ph) translocation has been accomplished primarily by cytogenetic analysis and reverse transcriptase polymerase chain reaction (RT-PCR). RT-PCR is highly sensitive (1/10(4)-10(6)) but not quantitatively reliable and is thus unsuitable for the monitoring of Ph-positive cells during therapy. Interphase fluorescence in situ hybridization (iFISH) allows analysis of a large number of cells (> 500) in a timely and efficiently quantitative manner. We obtained 118 peripheral blood (PB) and 127 bone marrow (BM) samples from 75 adult chronic myelogenous leukemia (CML) patients undergoing stem cell transplantation. We simultaneously performed nested RT-PCR and iFISH for all samples. False-positive cells were detected in 2.48% +/- 0.93% (mean +/- SD) of PB samples and 2.75% +/- 0.83% of BM samples. The iFISH results for PB and BM ranged from 1.4% to 92.8% and 1.0% to 93.8%, respectively. Correlation analysis of iFISH results for PB versus BM samples showed a strong relation (r = .993). A significant correlation (P < .05) was also found between iFISH and first-round RT-PCR. The sensitivity of BCR-ABL iFISH was similar to that of first-round RT-PCR, and iFISH results for PB and BM were also well correlated. Thus, iFISH analysis of PB and/or BM samples may be more clinically reliable than RT-PCR in the quantitative monitoring of BCR-ABL fusion in CML after transplantation. [ABSTRACT FROM AUTHOR]

Dasatinib is a potent second-generation tyrosine kinase inhibitor (TKI) used as a first-line treatment option for patients with chronic myeloid leukemia (CML). Currently, dose modification due to adverse events (AEs) is common in patients treated with dasatinib. This study compared the outcomes of two sequential prospective trials that enrolled patients with newly diagnosed chronic phase of CML (CP-CML) and initiated dasatinib at a starting dose of 100 mg daily. In the PCR-DEPTH study, CP-CML patients who started dasatinib 100 mg daily were enrolled and followed up, while in the DAS-CHANGE study, when patients achieved early molecular response with any grade of AEs were enrolled and treated with dasatinib 80 mg once daily. A total of 102 patients (PCR-DEPTH) and 90 patients (DAS-CHANGE) were compared. Although the median value of the relative dose intensity (RDI) of dasatinib was significantly higher in PCR-DEPTH than in DAS-CHANGE (99.6 % vs. 80.1 %, p <0.001), the MMR rate at 12months showed a trend toward superiority in DAS-CHANGE compared to PCR-DEPTH (77.1 % vs 65.2 %, p = 0.084). The frequencies of MR4.0 at 24 and 36 months were higher in DAS-CHANGE than in PCR-DEPTH (44.4 % vs 28.8 %, p = 0.052 and 63.6 % vs 40.3 %, p= 0.013, respectively). RDIs were not different according to the MMR, MR4.0 or MR4.5 in analyses using a pooled population. Our results suggest that early dose reduction of dasatinib does not compromise efficacy in patients achieving EMR at 3 months and could be an interventional strategy for improving long term outcomes. • Early dose reduction of dasatinib to 80 mg maintains efficacy in newly diagnosed chronic myeloid leukemia patients. • The DAS-CHANGE study showed higher rates of MR4.0 compared to the PCR-DEPTH study. • Median relative dose intensity was significantly lower in DAS-CHANGE compared to PCR-DEPTH. • Early dose reduction can be an effective strategy for improving long-term outcomes. [ABSTRACT FROM AUTHOR]

Bosutinib is an oral, dual SRC/ABL tyrosine kinase inhibitor (TKI) with clinical activity in Philadelphia chromosome-positive (Ph+) leukemia. We assessed the safety and tolerability of bosutinib 500 mg per day in a phase 1/2 study in chronic-phase (CP) chronic myeloid leukemia (CIVIL) or advanced Ph+ leukemia following resistance/intolerance to imatinib and possibly other TKIs. Patient cohorts included second-line CP CML (n = 286), third-/fourth-line CP CML (n = 118), and advanced leukemia (n = 166). Median bosutinib duration was 11.1 (range, 0.03-83.4) months. Treatment-emergent adverse events (TEAEs) in each cohort were primarily gastrointestinal (diarrhea [86%/83%/74%], nausea [46%/48%/ 48%], and vomiting [37%/38%/43%]). Diarrhea presented early, with few (8%) patients experiencing grade 3/4 events; dose reduction due to diarrhea occurred in 6% of affected patients. Grade 3/4 myelosuppression TEAEs were reported in 41% of patients; among affected patients, 46% were managed with bosutinib interruption and 32% with dose reduction. Alanine aminotransferase elevation TEAEs occurred in 17% of patients (grade 3/4, 7%); among patients managed with dose interruption, bosutinib rechallenge was successful in 74%. Bosutinib demonstrated acceptable safety with manageable toxicities in Ph+ leukemia. [ABSTRACT FROM AUTHOR]

• A tandem gene amplification method for detection of single nucleotide mutation (SNM) was developed. • Circular padlock DNA specific to target SNM was used for generating G-quadruplex via Rolling Circle Amplification. • Fluorescently visualized array-type multiple detection system was established for SNM detection in clinical samples. • Mutant RNA was identified as low as 8.0 fg with a concentration as low as 0.53 % in the mixture with wild-type RNA. Sensitive and accurate identification of single-nucleotide mutations (SNMs) has become crucial in the field of molecular diagnosis and personalized medicine. Here, we developed a highly sensitive fluorometric assay for detecting multiple SNMs by tandem gene amplification; reverse transcription PCR (RT-PCR) coupled with rolling circle amplification generating G-quadruplex (GQ-RCA). In tandem gene amplification, RT-PCR-amplified DNA from sample RNA was digested with lambda exonuclease, which degraded the strand harboring the phosphorylated 5′-end of amplicon DNA to generate single-stranded DNA (ssDNA). The resulting ssDNA was hybridized with padlock probe DNA, which can discriminate a single base mismatch. Depending on the presence of mismatched bases between the amplicon ssDNA and padlock probe DNA, ligation of both ends of the padlock DNA was evaluated. If ligation occurred, a circular form of padlock DNA was generated, which was eligible for RCA. The RCA process generates long stretches of ssDNA containing tandem repeats of G-quadruplex structures. The amplified ssDNA harboring G-quadruplex was fluorescently visualized and quantified using Thioflavin T fluorophore. Our assay detected mutant RNA containing an SNM as low as 8.3 fg and detected mutant RNA with a concentration as low as 0.53 % in the mixture with wild-type RNA. The fluorometric SNM detection method with tandem gene amplification was successfully applied for multiplex detection of SNMs in clinical samples derived from patients with chronic myeloid leukemia. Our method would be useful in clinical diagnosis for early detection and monitoring of multiple SNMs in cancer patients with proper treatment. [ABSTRACT FROM AUTHOR]

Highlights • 57.5% of total colonies were compound mutant colonies. • 89.3% of compound mutant colonies had at least one major mutation. • 13 patients had low-level allosteric site mutations throughout various TKI therapies. • Low-level mutations detected only by subcloning sequencing had clinical significance. • Higher sensitive assay should be used in case of TKI failure and multiple mutations. Abstract To analyze the pattern of multiple mutations detected by Sanger sequencing (SS), we performed subcloning sequencing using 218 samples from 45 patients with tyrosine kinase inhibitor resistant chronic myeloid leukemia. At the first time of multiple mutation detection by SS (baseline), a total of 19 major mutations from 45 samples were detected; these mutations were found in the following order: T315I (68.9%), E255 K (33.3%), Y253H (13.3%), G250E (13.3%), and F317 L (11.1%). Subcloning sequencing of 900 baseline colonies identified 556 different mutant types, and 791 among the 900 were colonies with major mutations (87.9%). The mutations were found in the following order: T315I (36.4%), E255 K (16.2%), Y253H (7.0%), G250E (6.7%), M351 T (6.6%), and E255 V (5.3%). In subcloning sequencing with 4357 colonies of 218 serial samples, 2506 colonies (57.5%) had compound mutations, among which 2238 colonies (89.3%) had at least one major mutation. The median number of mutations in compound mutant colonies was 2 (range, 2–7), and most were double (52.9%) or triple (28.7%) mutations. Additionally, some mutations in allosteric binding sites were detected as low level mutation in 13 patients. With the available retrospective samples before baseline, subcloning sequencing identified low-level mutations of various frequencies (median, 10%) to be major mutations in 20 patients. Thus, compound mutations involving T315I and P-loop mutations were the major components of multiple mutations, and some low-level mutations with potential clinical significance were detected by subcloning sequencing. Hence, more sensitive sequencing assays are needed in patients with multiple mutations. [ABSTRACT FROM AUTHOR]

We synthetized and investigated the anti-leukemic potential of the novel cytostatic bis(4-hydroxycoumarin) derivative OT-55 which complied with the Lipinski's rule of 5 and induced differential toxicity in various chronic myeloid leukemia (CML) cell models. OT-55 triggered ER stress leading to canonical, caspase-dependent apoptosis and release of danger associated molecular patterns. Consequently, OT-55 promoted phagocytosis of OT-55-treated CML cells by both murine and human monocyte-derived macrophages. Moreover, OT-55 inhibited tumor necrosis factor α-induced activation of nuclear factor-кB and produced synergistic effects when used in combination with imatinib to inhibit colony formation in vitro and Bcr-Abl+ patient blast xenograft growth in zebrafish. Furthermore, OT-55 synergized with omacetaxine in imatinib-resistant KBM-5 R cells to inhibit the expression of Mcl-1, triggering apoptosis. In imatinib-resistant K562 R cells, OT-55 triggered necrosis and blocked tumor formation in zebrafish in combination with omacetaxine. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the efficacy of nilotinib (NIL) versus high-dose imatinib (IM) versus sustained standard-dose IM for patients with chronic myeloid leukemia (CML) with suboptimal molecular response to first-line IM therapy. Patients with CML who achieved complete cytogenetic response (CCyR) but not major molecular response (MMR) after 18–24 months on first-line IM therapy were enrolled and divided into three treatment cohorts: NIL 800 mg/day (Cohort 1, n = 28) and IM 800 mg/day (Cohort 2, n = 28) in the RE-NICE study, and sustained IM 400 mg/day (Cohort 3, n = 52) in clinical practice. The primary efficacy variable of cumulative rate of MMR by 12 months was not different among the three cohorts. However, the cumulative incidence of MMR by 36 months was significantly higher in Cohort 1 than Cohort 3 (83.1% vs. 57.1%, P = 0.021), but there were no significant differences in Cohort 1 vs. 2 (P = 0.195) and Cohort 2 vs. 3 (P = 0.297). Different profile for adverse events was observed between NIL and high-dose IM therapy. In conclusion, our data suggested that switching to NIL may provide more effective long-term response than sustaining standard-dose IM for patients with suboptimal molecular response to first-line IM. [ABSTRACT FROM AUTHOR]

In chronic myelogenous leukemia (CML), treatment-free remission (TFR) is defined as maintaining a major molecular response (MMR) without a tyrosine kinase inhibitor (TKI), such as imatinib (IM). Several studies have investigated the safety of the first TFR (TFR 1) attempt and suggested recommendation guidelines for such an attempt. However, the plausibility and predictive factors for a second TFR (TFR 2) have yet to be reported. The present study included 21 patients in chronic myeloid leukemia who participated in twice repeated treatment stop attempts. We develop a mathematical model to analyze and explain the outcomes of TFR 2. Our mathematical model framework can explain patient-specific molecular response dynamics. Fitting the model to longitudinal BCR-ABL1 transcripts from the patients generated patient-specific parameters. Binary tree decision analyses of the model parameters suggested a model based predictive binary classification factor that separated patients into low- and high-risk groups of TFR 2 attempts with an overall accuracy of 76.2% (sensitivity of 81.1% and specificity of 69.9%). The low-risk group maintained a median TFR 2 of 28.2 months, while the high-risk group relapsed at a median time of 3.25 months. Further, our model predicted a patient-specific optimal IM treatment duration before the second IM stop that could achieve the desired TFR 2 (e.g., 5 years). [ABSTRACT FROM AUTHOR]

To explore the factors for achieving early molecular responses (EMR; BCR-ABL1 ≤10% at 3 months, ≤1% at 6 months) by imatinib (IM), baseline characteristics including individual BCR-ABL1 transcript level, dose intensity, and IM trough level on day 29 were analyzed in 286 chronic phase chronic myeloid leukemia patients. Distinct predictive factors for achieving EMR at 3 months and 6 months were noted. Blast count at diagnosis and IM trough level on day 29 were significantly associated with an achievement of 3-month EMR. Early decline of BCR-ABL1 transcript, low Sokal risk, and mean daily dose (≥350 mg/day) by 6 months were associated with an achievement of 6-month EMR. Understanding the predictive factors for EMR may provide additional information to guide clinical decisions on the changing therapies at each landmark. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the long-term clinical significance of an additional chromosomal abnormality (ACA), variant Philadelphia chromosome (vPh) at diagnosis, and newly developed other chromosomal abnormalities (OCA) in patients with chronic myeloid leukemia (CML) on imatinib (IM) therapy. Sequential cytogenetic data from 281 consecutive new chronic phase CML patients were analyzed. With a median follow-up of 78.6 months, the 22 patients with vPh (P = 0.034) or ACA (P = 0.034) at diagnosis had more events of IM failure than did the patients with a standard Ph. The 5-year overall survival (OS), event-free survival (EFS), and failure-free survival (FFS) rates for patients with vPh at diagnosis were 77.8%, 75.0%, and 53.3%, respectively; for patients with ACA at diagnosis, 100%, 66.3%, and 52.1%, respectively; and for patients with a standard Ph, 96.0%, 91.3%, and 83.7%, respectively. During IM therapy, eight patients developed an OCA, which had no impact on outcomes as a time-dependent covariate in our Cox proportional hazards regression models. This study showed that vPh was associated with poor OS and FFS and that ACA had adverse effects on EFS and FFS. In addition, no OCA, except monosomy 7, had any prognostic impact, suggesting that the development of OCA may not require a change in treatment strategy. [ABSTRACT FROM AUTHOR]

Rising BCR-ABL1 transcripts indicate potential loss of imatinib response in CML. We determined whether the BCR-ABLI doubling time could distinguish nonadherence from resistance as the cause of lost response. Distinct groups were examined: (1 ) acquired clinical resistance because of blast crisis and/or BCR-ABLI mutations; and (2) documented ima-tinib discontinuation/interruption. Short doubling times occurred with blast crisis (median, 9.0 days; range, 6.1-17.6 days; n = 12 patients), relapse after imatinib dis-continuation in complete molecular re-sponse (median, 9.0 days; range, 6.9-26.5 days; n = 17), and imatinib interruption during an entire measurement interval (median, 9.4 days; range, 4.2-17.6 days; n = 12; P = .72). Whereas these doubling times were consistently short and indi-cated rapid leukemic expansion, fold rises were highly variable: 71-, 9.5-, and 10.5-fold, respectively. The fold rise depended on the measurement interval, whereas the doubling time was independent of the interval. Longer doubling times occurred for patients with mutations who main-tained chronic phase (CP: median, 48 days; range, 17.3-143 days; n = 29; P < .0001). Predicted short and long doubling times were validated on an independent cohort monitored elsewhere. The doubling time revealed major differences In kinetics ac-cording to clinical context. Long doubling times observed with mutations in CP al-low time for intervention. A short dou-bling time for a patient in CP should raise the suspicion of nonadherence. (Blood. 2012; 119(18):4264-4271 ) [ABSTRACT FROM AUTHOR]

Abstract: Understanding the impact of second-line tyrosine kinase inhibitor therapy on the health-related quality of life (HRQOL) of imatinib (IM)-resistant and IM-intolerant chronic phase chronic myeloid leukemia (CP CML) patients is important given the increased survival that comes with therapy. As part of a bosutinib single-arm phase 2 trial, 200 IM-resistant and 88 IM-intolerant CP CML patients’ HRQOL was assessed prior to and throughout treatment with the Functional Assessment of Cancer Therapy-Leukemia (FACT-Leu). Little HRQOL impairment was demonstrated at baseline. Over the course of 96weeks on bosutinib therapy, patients noted statistically significant and/or clinically meaningful improvements on several FACT-Leu scales. [Copyright &y& Elsevier]

• Bosutinib is effective for Ph+ CML patients resistant/intolerant to prior therapy. • Some patients receiving TKIs require dose reductions to manage AEs. • A phase I/II study assessed efficacy and safety after dose reductions (for AEs). • Dose reductions can maintain/sometimes improve efficacy and improve tolerability. The recommended starting dose of bosutinib is 500 mg/day for chronic-phase (CP) or accelerated-/blast-phase Philadelphia chromosome–positive (Ph+) chronic myeloid leukemia (CML) resistant/intolerant to prior therapy. However, some patients may require dose reductions to manage the occurrences of adverse events (AEs). Bosutinib efficacy and safety were evaluated following dose reductions in a phase I/II study of Ph+ patients with CP CML resistant/intolerant to imatinib or imatinib plus dasatinib and/or nilotinib, and those with accelerated-/blast-phase CML or acute lymphoblastic leukemia after at least imatinib treatment. In all, 570 patients with ≥4 years' follow-up were included in this analysis. Among 144 patients who dose-reduced to bosutinib 400 mg/day (without reduction to 300 mg/day), 22 (15 %) had complete cytogenetic response (CCyR) before and after reduction, 40 (28 %) initially achieved CCyR after reduction, and 4 (3 %) only had CCyR before reduction. Among 95 patients who dose-reduced to bosutinib 300 mg/day, 23 (24 %) had CCyR before and after reduction, 13 (14 %) initially achieved CCyR after reduction, and 3 (3 %) only had CCyR before reduction. Results were similar to matched controls who remained on 500 mg/day, indicating dose reductions had not substantially affected efficacy. The incidence of treatment-emergent AEs was lower after dose reductions, particularly for gastrointestinal events. The incidence of hematologic toxicities generally was similar before and after dose reduction. The management of AEs with bosutinib through dose reduction can lead to improved/maintained efficacy and better tolerability; still, approximately half of patients on treatment at year 4 maintained a dose of ≥500 mg/day. ClinicalTrials.gov: NCT00261846. [ABSTRACT FROM AUTHOR]

Abstract: This study was designed to identify the cell surface protein markers that can differentiate between chronic myeloid leukemia (CML) and acute promyelocytic leukemia cells (APL). The differentially expressed plasma membrane proteins were analyzed between CML cell line (K562) and APL cell line (NB4) using the comparative proteomic approach. The cell membrane proteins were enriched by labeling with a membrane-impermeable biotinylation reagent, sulfo-NHS-SS-Biotin, and subjected to liquid chromatography tandem mass spectrometry (LC–MS/MS). By comparative proteomic analysis of K562 and NB4 cells, we identified 25 membrane and 14 membrane-associated proteins. The result of LC–MS/MS combined with chemical tagging method was validated by confirming the expression and localization of one of the differentially expressed plasma membrane proteins, CD43, by FACS and confocal microscopy. Our results indicate that CD43 could be a potential candidate for differentiating CML from APL. [Copyright &y& Elsevier]

BCR-ABL1 point mutation-mediated resistance to tyrosine kinase inhibitor (TKI) therapy in Philadelphia chromosome-positive (Ph+) leukemia is effectively managed with several approved drugs, including ponatinib for BCR-ABL1T315I-mutant disease. However, therapy options are limited for patients with leukemic clones bearing multiple BCR-ABL1 mutations. Asciminib, an allosteric inhibitor targeting the myristoyl-binding pocket of BCR-ABL1, is active against most single mutants but ineffective against all tested compound mutants. We demonstrate that combining asciminib with ATP site TKIs enhances target inhibition and suppression of resistant outgrowth in Ph+ clinical isolates and cell lines. Inclusion of asciminib restores ponatinib's effectiveness against currently untreatable compound mutants at clinically achievable concentrations. Our findings support combining asciminib with ponatinib as a treatment strategy for this molecularly defined group of patients. • Most BCR-ABL1 point mutants but not compound mutants are sensitive to asciminib • Variants at BCR-ABL1 position F359 are linked with asciminib resistance in patients • Combination of asciminib with ponatinib restores efficacy against compound mutants Most clinical BCR-ABL1 compound mutants are insensitive to current clinical tyrosine kinase inhibitors. Eide et al. show that adding asciminib, an allosteric inhibitor, to ponatinib, an ATP site inhibitor, effectively targets compound mutants and provides a potential mechanism for the collaborative effect. [ABSTRACT FROM AUTHOR]