BACKGROUND: A lower dosage of tyrosine kinase inhibitors (TKIs) in patients with chronic myeloid leukaemia (CML) has shown efficacy in managing short-term toxicity and maintaining a deep molecular response in patients who fail to achieve treatment-free remission. METHOD: From over 700 patients with CML who were treated at two centres over the last three decades, this retrospective study identified eight patients characterised by long-term treatment failure and simultaneous prolonged significant haematologic toxicity that prevented the use of the standard tyrosine kinase inhibitor dosage. RESULTS: Patients had a high or intermediate ELTS risk score, and most had significant comorbidities. Two patients were treated previously with busulfan, and four were aged over 70, which might explain the reduced pool of normal haematopoietic stem cells. However, concomitant myelodysplastic syndrome or the presence of clonal haematopoiesis of indeterminate potential was not demonstrated. Despite prolonged treatment failure, the survival of these patients (who were ineligible for stem cell transplantation) ranged from 45-396 months. Neither mutations in the ABL kinase domain nor additional cytogenetic abnormalities developed during the treatment of these patients, prompting speculation about the low selective pressure of low-dose tyrosine kinase inhibitors and/or the absence of mutations at diagnosis. CONCLUSION: It is important not to stop treatment with tyrosine kinase inhibitors at a low personalised dosage in CML patients with prolonged significant haematologic toxicity despite long-term treatment failure.

• Klíčová slova
• Chronic myeloid leukaemia, Haematologic toxicity, Intermittent dosage, Kinase domain mutation, Low dosage, Tyrosine kinase inhibitor,
• Publikační typ
• časopisecké články MeSH

Ponatinib is a tyrosine kinase inhibitor (TKI) directed against BCR-ABL1 which is successfully used in patients with BCR-ABL1 T315I+ chronic myeloid leukemia (CML). However, BCR-ABL1 compound mutations may develop during therapy in these patients and may lead to drug resistance. Asciminib is a novel drug capable of targeting most BCR-ABL1 mutant-forms, including BCR-ABL1T315I, but remains ineffective against most BCR-ABL1T315I+ compound mutation-bearing sub-clones. We demonstrate that asciminib synergizes with ponatinib in inducing growth-arrest and apoptosis in patient-derived CML cell lines and murine Ba/F3 cells harboring BCR-ABL1 T315I or T315I-including compound mutations. Asciminib and ponatinib also produced cooperative effects on CRKL phosphorylation in BCR-ABL1-transformed cells. The growth-inhibitory effects of the drug combination 'asciminib+ponatinib' was further enhanced by hydroxyurea (HU), a drug which has lately been described to suppresses the proliferation of BCR-ABL1 T315I+ CML cells. Cooperative drug effects were also observed in patient-derived CML cells. Most importantly, we were able to show that the combinations 'asciminib+ponatinib' and 'asciminib+ponatinib+HU' produce synergistic apoptosis-inducing effects in CD34+/CD38- CML stem cells obtained from patients with chronic phase CML or BCR-ABL1 T315I+ CML blast phase. Together, asciminib, ponatinib and HU synergize in producing anti-leukemic effects in multi-resistant CML cells, including cells harboring T315I+ BCR-ABL1 compound mutations and CML stem cells. The clinical efficacy of this TKI combination needs to be evaluated within the frame of upcoming clinical trials.

• Klíčová slova
• BCR-ABL1 compound mutations, BCR-ABL1T315I, CML, asciminib, drug combinations, hydroxyurea, leukemic stem cells, ponatinib,
• Publikační typ
• časopisecké články MeSH

The therapeutic landscape of chronic myeloid leukemia (CML) has profoundly changed over the past 7 years. Most patients with chronic phase (CP) now have a normal life expectancy. Another goal is achieving a stable deep molecular response (DMR) and discontinuing medication for treatment-free remission (TFR). The European LeukemiaNet convened an expert panel to critically evaluate and update the evidence to achieve these goals since its previous recommendations. First-line treatment is a tyrosine kinase inhibitor (TKI; imatinib brand or generic, dasatinib, nilotinib, and bosutinib are available first-line). Generic imatinib is the cost-effective initial treatment in CP. Various contraindications and side-effects of all TKIs should be considered. Patient risk status at diagnosis should be assessed with the new EUTOS long-term survival (ELTS)-score. Monitoring of response should be done by quantitative polymerase chain reaction whenever possible. A change of treatment is recommended when intolerance cannot be ameliorated or when molecular milestones are not reached. Greater than 10% BCR-ABL1 at 3 months indicates treatment failure when confirmed. Allogeneic transplantation continues to be a therapeutic option particularly for advanced phase CML. TKI treatment should be withheld during pregnancy. Treatment discontinuation may be considered in patients with durable DMR with the goal of achieving TFR.

• MeSH
• analýza přežití MeSH
• aniliny terapeutické užití   MeSH
• antitumorózní látky terapeutické užití   MeSH
• bcr-abl fúzové proteiny antagonisté a inhibitory   genetika   metabolismus   MeSH
• chinoliny terapeutické užití   MeSH
• chronická myeloidní leukemie diagnóza   farmakoterapie   genetika   mortalita   MeSH
• dasatinib terapeutické užití   MeSH
• exprese genu MeSH
• imatinib mesylát terapeutické užití   MeSH
• inhibitory proteinkinas terapeutické užití   MeSH
• klinické rozhodování MeSH
• konsensuální konference jako téma MeSH
• kvalita života MeSH
• lidé MeSH
• management nemoci MeSH
• monitorování fyziologických funkcí MeSH
• naděje dožití trendy   MeSH
• nitrily terapeutické užití   MeSH
• pyrimidiny terapeutické užití   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• aniliny MeSH
• antitumorózní látky MeSH
• bcr-abl fúzové proteiny MeSH
• BCR-ABL1 fusion protein, human MeSH Prohlížeč
• bosutinib MeSH Prohlížeč
• chinoliny MeSH
• dasatinib MeSH
• imatinib mesylát MeSH
• inhibitory proteinkinas MeSH
• nilotinib MeSH Prohlížeč
• nitrily MeSH
• pyrimidiny MeSH

Cytogenomic investigations of haematological neoplasms, including chromosome banding analysis, fluorescence in situ hybridisation (FISH) and microarray analyses have become increasingly important in the clinical management of patients with haematological neoplasms. The widespread implementation of these techniques in genetic diagnostics has highlighted the need for guidance on the essential criteria to follow when providing cytogenomic testing, regardless of choice of methodology. These recommendations provide an updated, practical and easily available document that will assist laboratories in the choice of testing and methodology enabling them to operate within acceptable standards and maintain a quality service.

• MeSH
• akutní myeloidní leukemie genetika   MeSH
• chronická myeloidní leukemie MeSH
• hematologické nádory genetika   MeSH
• hybridizace in situ fluorescenční MeSH
• lidé MeSH
• lymfom genetika   MeSH
• mikročipová analýza MeSH
• mnohočetný myelom genetika   MeSH
• myelodysplastické syndromy MeSH
• pruhování chromozomů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

INTRODUCTION: Imatinib mesylate is the drug of choice for patients with chronic myeloid leukemia (CML). Imatinib pharmacokinetics is affected by a number of transport proteins and enzymes. MATERIAL AND METHODS: In the present study we evaluated the association of eight polymorphisms in the seven genes CYP3A5*3 (rs776746), CYP3A4*1 (rs2740574), CYP2C9*3 (rs1057910), SLC22A1 (rs683369), ABCB1 (rs1045642, rs1128503), ABCG2 (rs2231142) and ABCC2 (rs717620) with imatinib plasma level and achieving an optimal clinical response in 112 CML patients (53 men and 59 women). RESULTS: No association was found between the examined polymorphisms in rs776746, rs2740574, rs1057910, rs683369, rs1045642, rs1128503, rs2231142, rs717620 and the achieved imatinib plasma level. The influence of rs776746 (CYP3A5*3) on the achievement of a complete cytogenetic response (CCyR) at 6 months was borderline non-significant (p = 0.06). Furthermore, no association was demonstrated between rs776746 polymorphisms and the achievement of a major molecular response (MMR) at 12 or 18 months. Polymorphisms rs776746, rs2740574, rs1057910, rs683369, rs1045642, rs1128503, rs2231142, rs717620 showed no impact on the optimal therapeutic response. CONCLUSIONS: Despite the results of some other studies, no other polymorphism we analyzed was associated with imatinib plasma level or clinical response. The treatment outcomes cannot be predicted using the candidate gene approach and treatment decisions cannot be made according to the polymorphisms investigated in this study.

• Klíčová slova
• chronic myeloid leukemia, clinical response, genetic polymorphisms, imatinib,
• Publikační typ
• časopisecké články MeSH

Molecular monitoring of chronic myeloid leukemia patients using robust BCR-ABL1 tests standardized to the International Scale (IS) is key to proper disease management, especially when treatment cessation is considered. Most laboratories currently use a time-consuming sample exchange process with reference laboratories for IS calibration. A World Health Organization (WHO) BCR-ABL1 reference panel was developed (MR(1)-MR(4)), but access to the material is limited. In this study, we describe the development of the first cell-based secondary reference panel that is traceable to and faithfully replicates the WHO panel, with an additional MR(4.5) level. The secondary panel was calibrated to IS using digital PCR with ABL1, BCR and GUSB as reference genes and evaluated by 44 laboratories worldwide. Interestingly, we found that >40% of BCR-ABL1 assays showed signs of inadequate optimization such as poor linearity and suboptimal PCR efficiency. Nonetheless, when optimized sample inputs were used, >60% demonstrated satisfactory IS accuracy, precision and/or MR(4.5) sensitivity, and 58% obtained IS conversion factors from the secondary reference concordant with their current values. Correlation analysis indicated no significant alterations in %BCR-ABL1 results caused by different assay configurations. More assays achieved good precision and/or sensitivity than IS accuracy, indicating the need for better IS calibration mechanisms.

• MeSH
• bcr-abl fúzové proteiny analýza   normy   MeSH
• geny abl MeSH
• kalibrace MeSH
• lidé MeSH
• polymerázová řetězová reakce MeSH
• protoonkogenní proteiny c-bcr genetika   MeSH
• referenční standardy MeSH
• Světová zdravotnická organizace MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• BCR protein, human MeSH Prohlížeč
• bcr-abl fúzové proteiny MeSH
• protoonkogenní proteiny c-bcr MeSH

Most reports on chronic myeloid leukaemia (CML) treatment with tyrosine kinase inhibitors (TKIs) focus on efficacy, particularly on molecular response and outcome. In contrast, adverse events (AEs) are often reported as infrequent, minor, tolerable and manageable, but they are increasingly important as therapy is potentially lifelong and multiple TKIs are available. For this reason, the European LeukemiaNet panel for CML management recommendations presents an exhaustive and critical summary of AEs emerging during CML treatment, to assist their understanding, management and prevention. There are five major conclusions. First, the main purpose of CML treatment is the antileukemic effect. Suboptimal management of AEs must not compromise this first objective. Second, most patients will have AEs, usually early, mostly mild to moderate, and which will resolve spontaneously or are easily controlled by simple means. Third, reduction or interruption of treatment must only be done if optimal management of the AE cannot be accomplished in other ways, and frequent monitoring is needed to detect resolution of the AE as early as possible. Fourth, attention must be given to comorbidities and drug interactions, and to new events unrelated to TKIs that are inevitable during such a prolonged treatment. Fifth, some TKI-related AEs have emerged which were not predicted or detected in earlier studies, maybe because of suboptimal attention to or absence from the preclinical data. Overall, imatinib has demonstrated a good long-term safety profile, though recent findings suggest underestimation of symptom severity by physicians. Second and third generation TKIs have shown higher response rates, but have been associated with unexpected problems, some of which could be irreversible. We hope these recommendations will help to minimise adverse events, and we believe that an optimal management of them will be rewarded by better TKI compliance and thus better CML outcomes, together with better quality of life.

• MeSH
• chronická myeloidní leukemie komplikace   farmakoterapie   MeSH
• inhibitory proteinkinas škodlivé účinky   terapeutické užití   MeSH
• lidé MeSH
• nežádoucí účinky léčiv MeSH
• tyrosinkinasy antagonisté a inhibitory   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• inhibitory proteinkinas MeSH
• tyrosinkinasy MeSH

In chronic myeloid leukemia (CML) and Philadelphia-positive (Ph+) acute lymphoblastic leukemia (ALL) patients who fail imatinib treatment, BCR-ABL1 mutation profiling by Sanger sequencing (SS) is recommended before changing therapy since detection of specific mutations influences second-generation tyrosine kinase inhibitor (2GTKI) choice. We aimed to assess i) in how many patients who relapse on second-line 2GTKI therapy next generation sequencing (NGS) may track resistant mutations back to the sample collected at the time of imatinib resistance, before 2GTKI start (switchover sample) and ii) whether low level mutations identified by NGS always undergo clonal expansion. To this purpose, we used NGS to retrospectively analyze 60 imatinib-resistant patients (CML, n = 45; Ph+ ALL,n = 15) who had failed second-line 2GTKI therapy and had acquired BCR-ABL1 mutations (Group 1) and 25 imatinib-resistant patients (CML, n = 21; Ph+ ALL, n = 4) who had responded to second-line 2GTKI therapy, for comparison (Group 2). NGS uncovered that in 26 (43%) patients in Group 1, the 2GTKI-resistant mutations that triggered relapse were already detectable at low levels in the switchover sample (median mutation burden, 5%; range 1.1%-18.4%). Importantly, none of the low level mutations detected by NGS in switchover samples failed to expand whenever the patient received the 2GTKI to whom they were insensitive. In contrast, no low level mutation that was resistant to the 2GTKI the patients subsequently received was detected in the switchover samples from Group 2. NGS at the time of imatinib failure reliably identifies clinically relevant mutations, thus enabling a more effective therapeutic tailoring.

• Klíčová slova
• BCR-ABL1, Next-generation sequencing, acute lymphoblastic leukemia, chronic myeloid leukemia, tyrosine kinase inhibitors,
• MeSH
• akutní lymfatická leukemie farmakoterapie   genetika   MeSH
• bcr-abl fúzové proteiny genetika   MeSH
• chemorezistence genetika   MeSH
• chronická myeloidní leukemie farmakoterapie   genetika   MeSH
• dasatinib terapeutické užití   MeSH
• dospělí MeSH
• imatinib mesylát terapeutické užití   MeSH
• inhibitory proteinkinas terapeutické užití   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mutační analýza DNA metody   MeSH
• retrospektivní studie MeSH
• senioři MeSH
• vysoce účinné nukleotidové sekvenování metody   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bcr-abl fúzové proteiny MeSH
• BCR-ABL1 fusion protein, human MeSH Prohlížeč
• dasatinib MeSH
• imatinib mesylát MeSH
• inhibitory proteinkinas MeSH

We evaluated responses to the treatment and long-term outcomes of chronic myeloid leukemia patients treated with imatinib as first-line treatment in routine clinical setting from two countries with centralized tyrosine kinase inhibitors (TKIs) treatment. We assessed prognostic significance of European LeukemiaNet (ELN) 2006- and 2009-defined responses and the prognostic value of molecular responses at defined time points on 5-year survivals. Among the cumulative rates of incidence of hematologic, cytogenetic, and molecular responses and all important survival parameters, we evaluated the prognostic significance of different BCR-ABL transcript-level ratios (≤1%; >1%-≤10%; >10%) at 3, 6, 12, and 18 months (n = 199). The ELN optimal response criteria and their predictive role were significantly beneficial for event-free survival at all given time points. We found significant improvement in survivals of patients with BCR-ABL lower than 10% in the 6th and 12th months. Significantly better outcome was found in patients who achieved major molecular response (MMR) in the 12th month. The cumulative incidences of complete cytogenetic response (CCyR) and MMR were significantly associated with the molecular response in the 3rd month. The ELN response criteria and their predictive role were helpful at given time points; however, the 2009 definition did not significantly alter the prognostic accuracy compared with that of the 2006 definition. The significant value was observed for cytogenetic responses at the 6th and 12th month. Moreover, progression-free and event-free survivals were improved with MMR at the 12th month.

• Klíčová slova
• BCR-ABL ratios, CML, ELN definitions, imatinib,
• MeSH
• antitumorózní látky terapeutické užití   MeSH
• bcr-abl fúzové proteiny genetika   MeSH
• benzamidy terapeutické užití   MeSH
• chronická myeloidní leukemie farmakoterapie   genetika   MeSH
• dospělí MeSH
• imatinib mesylát MeSH
• inhibitory proteinkinas terapeutické užití   MeSH
• lidé středního věku MeSH
• lidé MeSH
• míra přežití MeSH
• mladiství MeSH
• mladý dospělý MeSH
• piperaziny terapeutické užití   MeSH
• prognóza MeSH
• pyrimidiny terapeutické užití   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• výsledek terapie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antitumorózní látky MeSH
• bcr-abl fúzové proteiny MeSH
• benzamidy MeSH
• imatinib mesylát MeSH
• inhibitory proteinkinas MeSH
• piperaziny MeSH
• pyrimidiny MeSH

BACKGROUND AND OBJECTIVE: The availability of different tyrosine kinase inhibitors (TKIs) with distinct anti-leukemic potency enables optimization of current therapeutic regimens; however, some patients lose their therapy response and acquire TKI resistance. In this study, we describe a single-center experience of monitoring BCR-ABL1 kinase domain (KD) mutations and discuss the impact of treatment on mutation selection. METHODS: Chronic myelogenous leukemia (CML) patients treated with TKIs at the Department of Internal Medicine-Hematology and Oncology, Masaryk University and University Hospital Brno during 2003-2011 were included in this study. A total number of 100 patients who did not achieve an optimal therapy response or who lost their therapy response were screened for the presence of BCR-ABL1 KD mutations, using direct sequencing. RESULTS: Our data show that pretreatment with non-specific non-TKI drugs prior to TKI therapy does not preferentially select for initial BCR-ABL1 KD mutations, in contrast to first-line imatinib therapy, which shows a clear predominance of T315I or P-loop mutations compared with mutations located in other KD regions. In addition, the median time to detection of P-loop mutations was substantially shorter in patients treated with first-line imatinib than in those pretreated with non-TKI drugs. Furthermore, analysis of CML patients who had recurrent resistance to TKI therapy revealed possible therapy-driven selection of BCR-ABL1 KD mutations. Finally, we confirm the previously described poor prognosis of CML patients with mutations in the BCR-ABL1 KD, since 40.0% of our CML patients who harbored a BCR-ABL1 KD mutation died from CML while receiving TKI treatment. Moreover, among the patients who are still on treatment, 27.8% have already progressed. Our data also confirm the unique position of the T315I mutation with respect to its strong resistance to currently approved TKIs. CONCLUSION: On the basis of the 'real-life' data described in this study, it is possible that the therapy itself results in its failure and selects the most resistant mutations under the selective pressure of the applied therapy regimen in some CML patients who harbor BCR-ABL1 KD mutations.

• MeSH
• antitumorózní látky terapeutické užití   MeSH
• bcr-abl fúzové proteiny genetika   MeSH
• chronická myeloidní leukemie farmakoterapie   genetika   MeSH
• dospělí MeSH
• inhibitory proteinkinas terapeutické užití   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mutace MeSH
• senioři MeSH
• tyrosinkinasy genetika   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antitumorózní látky MeSH
• bcr-abl fúzové proteiny MeSH
• inhibitory proteinkinas MeSH
• tyrosinkinasy MeSH