Background. Somatic mutations in chronic myeloid leukemia (CML) patients are considered as possible factors for the failure of tyrosine kinase inhibitor (TKI) therapy, and the study of their characteristics is of interest.Aim. To evaluate the genetic profile of blood cells in CML patients using nextgeneration sequencing.Materials and methods. Retrospective study was conducted in two groups of patients: group 1 with TKI therapy failure (n = 29) and group 2 with optimal response to TKI therapy (n = 29). The target panel for nextgeneration sequencing included 19 genes: ASXL1, DNMT3A, FLT3, IDH1, IDH2, NPM1, RUNX1, SF3B1, SRSF2, TET2, TP53, U2AF2, KIT, WT1, CEBPA, ZRSR2, JAK2, GATA2, ABL1. In order to assess clonal evolution, additional samples were examined at a retrospective point in time closest to the primary CML diagnosis.Results. In group 1, mutations in 8 genes (including ABL1) were identified in 19/29 (66 %) patients. Excluding ABL1, mutations were identified in 15 (52 %) patients. In 9 (31 %) patients, >1 mutation (2 to 4) was detected. Frequency of genes mutations in group 1: ABL1 in 11 (38 %) patients, ASXL1 in 9 (31 %) patients, DNMT3A in 3 (10 %) patients, RUNX1, CEBPA in 2 patients (7 %), WT1, NPM1, TET2 in 1 patient (3.5 %). In 7 (24 %) patients there was a combination of mutations in ABL1 gene and in another gene; the most frequent combination of mutations in genes: ABL1 + ASXL1 – in 4 patients (14 %). The dynamics of mutant clones in group 1 was evaluated in 21/29 (72 %) patients. In 10/21 (48 %) patients somatic mutations in genes appeared during CML treatment, in 14/21 (67 %) patients previously detected mutations persisted, in 1 (5 %) the mutation disappeared. In group 2, somatic mutations were detected in 2/29 (7 %) patients: in DNMT3A (ariant Allele Frequency (AF) 5 %) and TP53 (AF 9 %) genes – these mutations were not detected at the diagnosis of CML. In one patient ASXL1 mutation (AF 5 %) was detected only at diagnosis, and was not detected subsequently with optimal response to therapy.Conclusion. The presence of somatic gene mutations is associated with a resistant CML course: somatic mutations in genes other than ABL1 were more common in CML patients with TKI therapy failure than in those with optimal response: 52 % vs. 7 % (p ≤0.05). Mutations in ASXL1 (31 %) and DNMT3A (10 %) were the most frequently detected. The frequency of ABL1 and ASXL1 mutations combination amounted to 14 %. uring followup, somatic mutations predominantly persisted or appeared over time in CML patients with TKI therapy resistance.

Aim. To assess the efficacy and tolerability of asciminib in chronic myeloid leukemia (CML) patients after failure of ≥ 2 lines of tyrosine kinase inhibitors (TKIs) therapy under the МАР (Managed Access Program, NCT04360005) in Russia. Materials & Methods. The study enrolled 68 patients with Ph-positive CML chronic phase (CF), over 18 years of age, after failure of ≥ 2 lines of TKI therapy. The analysis was conducted on data from 50 patients who were followed-up for at least 3 months and did not undergo allo-HSCT. Dosing regimens were prescribed depending on T315I mutation. Asciminib 200 mg per os was administered twice a day to 20 patients with this mutation, and asciminib 40 mg per os was administered twice a day to 30 patients without this mutation. By the time of admission into the MAP, there were 42 (82 %) CF CML patients as well as 8 patients with second CF after accelerated phase (AF, n = 7) and myeloid blast crisis (BC, n = 1). None of them could be treated with any therapeutic alternative. 92 % of patients had received ≥ 3 lines of prior TKI therapy. Overall survival (OS) and discontinuation-free survival were estimated by the Kaplan-Meier method. A cumulative incidence function (CIF) was used to calculate the probability of achieving response. Multivariate analysis was based on Cox regression model. Results. The median asciminib treatment duration was 11 months (range 4–30 months). The probable 2-year OS was 96 %. After 12 and 24 months, discontinuation-free survival was 92 % and 70 %, respectively. On asciminib therapy, complete cytogenetic (CCyR/МR2), major molecular (MMR), and deep molecular (MR4) responses were achieved in 17 (42 %), 14 (30 %), and 9 (19 %) patients who had not responded to prior treatment at the point of enrollment. After completing the 12- and 24-month therapy, the probability of CCyR/МR2 achievement was 44 % and 62 %, that of MMR achievement was 32 % and 40 %, and that of MR4 achievement was 26 % and 37 %, respectively. The patients treated with different doses did not significantly differ in achieving either CCyR/МR2 or MMR. By multivariate analysis, the independently significant factor impacting the probability of achieving MMR on asciminib treatment was the best MR (BCR::ABL1 < 1 % vs. 1–10 % vs. ≥ 10 %) after prior TKI therapy (hazard ratio 7.5873; p = 0.0072). In 22 (44 %) patients, adverse events (AEs) of all grades were observed, and 8 (16 %) patients showed AEs grade 3/4 (predominantly thrombocythemia and neutropenia). None of the patients discontinued asciminib treatment due to AEs. Conclusion. Asciminib demonstrated highly promising efficacy in previously TKI-treated patients with T315I mutation (200 mg BID) and without it (40 mg BID). Asciminib can be regarded as therapeutic option after failure of other TKIs. Different doses of asciminib were equally well tolerated, which makes it applicable for patients with intolerance to other TKIs and also provides ground for considering dose increases in non-responders. Good prospects are also expected for studying asciminib efficacy at earlier treatment stages (in first or second lines) as well as in combination with ATP-binding TKIs in CML patients with insufficient response to TKI treatment.

Background: Asciminib (ASC) is a novel, first in class ‘specifically targeting the ABL myristate pocket (STAMP) inhibitor. Recent update of the ASCEMBL phase 3 data showed a superior cumulative incidence of major molecular rate (MMR) of 33.2% with ASC over bosutinib (BOS) at 18.6% by 48 weeks and higher MR4 rate (BCR-ABL1 ≤0.01%) of 14.0% with ASC over 6.6% with BOS at 48 weeks in CML patients (pts) in chronic phase (CP) who have failed at least two lines of TKI therapy. Aims: Canadian and Russian groups individually reported their real-world experiences of ASC therapy under the Managed Access Program in heavily pre-treated CML patients. Methods: Data was collected, updated and merged from 80 CML pts treated with ASC between Nov 2018 - Dec 2021 (n=57 in Russia; n=23 in Canada). Median age was 57 years (range 20-92). The median number of previous TKIs was 4 (range 2-6); Imatinib (n=74, 93%), dasatinib (n=64, 80%), nilotinib (n=58, 73%), bosutinib (n=51, 64%), ponatinib (n=35, 44%), and others (n=13, 16%). Median duration from diagnosis to ASC treatment was 92 mo (months) (range 11-310). 27 (34%) pts had a past history of clinically significant cardiovascular disease or high risk profile for cardiovascular disease. Of the 80 pts, 27 (34%) had a preexisting T315I mutation and 18 (23%) had a non-T315I mutation. Pts failed previous TKI therapy due to A)resistance or suboptimal response (n=59; 74%) and B)intolerance (n=21; 26%). BCR-ABL qPCRs were monitored at each institution. Achievement of MMR and molecular response of 4 log reduction (MR4) was assessed at 6 and 12 mo. Results: With a median of 9 mo of follow-up (range 1-38), MMR was noted in 15/68 (22%) and 14/36 pts (39%) evaluated at 6 and 12 mo, respectively. MR4 was noted in 11/68 (16%) and 9/36 pts (25%) at 6/12 mo. The cumulative incidence of MMR and MR4 was 32.6% (20.9-44.8%) and 15.9% (7.9-26.3%) at 12 mo. The probability of freedom from treatment failure (FTF) at 12 mo was 42.4% (27.6-56.4%), based on the ELN 2013 failure criteria for 2nd line therapy or beyond. In the overall population (n=80), FTF was significantly associated with reason for switch to ASC (p=0.006), and there was a trend toward association of FTF with disease phase (p=0.08) and ponatinib therapy (p=0.12), but not with ABL1 kinase domain mutation (p=0.402), additional cytogenetic abnormality (p=0.908), nor cardiovascular risk profile (p=0.345). When analysis was restricted to the patients in CML-CP (n=65), a median duration of FTF was calculated as 11.6 mo, while the 12 mo FTF rate was 46.8% (28.9-62.8%). The patients previously treated with ponatinib (n=25) showed a 27.7% (8.4-51.4%) FTF rate at 12 mo, which was lower than that in those naïve to ponatinib (n=40), 61.7% (34.9-80.2%; p=0.023). Those switched to ASC for intolerance (n=21) showed higher 12 mo FTF rate of 81.2% (41.5 -95.2%) compared to 29.4% (11.3-50.2%) in those with resistance (n=44; p=0.008). Fifteen pts discontinued ASC due to treatment failure (n=11), progression of disease to blast phase (n=3) or grade 4 thrombocytopenia (n=1). No cardiovascular event was noted. Image:Summary/Conclusion: This combined Canadian and Russian real-world experience of ASC study includes heavily pretreated CML pts including 15 pts in advanced phase. The MMR and MR4 rates were comparable in those in CP, while it was lower in non-CP pts. The 12 mo FTF rate of 42.4% was comparable to the one reported from the ASCEMBL study, 57.7%, considering that this group includes more patients who had heavily pre-treated with advanced disease. *AGT and FK contributed equally as co-first author.

Актуальность. Отмена терапии ингибиторами тирозинкиназ (ИТК) у больных хроническим миелоидным лейкозом (ХМЛ) с оптимальным ответом, особенно у пациентов с явлениями лекарственной токсичности, является актуальным вопросом. По результатам многочисленных клинических исследований вероятность сохранения ремиссии без лечения (РБЛ) у больных ХМЛ с глубоким молекулярным ответом (ГМО) составляет примерно 40–60 %. В последнее время большое внимание уделяется персонализированному подходу к лечению, заключающемуся в модификации дозы ИТК с целью уменьшить или предотвратить развитие нежелательных явлений терапии. Во многих крупных ретроспективных исследованиях продемонстрировано, что применение редуцированных доз ИТК у больных ХМЛ с большим молекулярным ответом (БМО) и ГМО — безопасная опция терапии. Наблюдение за больными, получающими ИТК в сниженных дозах, также выполняется в рамках проспективных клинических исследований как этап перед отменой терапии. Данный подход демонстрирует, что вероятность сохранения РБЛ после фазы редукции доз ИТК составляет около 70 %, что превышает аналогичный показатель после отмены ИТК в стандартных дозах. Цель. Представить обоснование, цель и основные задачи исследования, дизайн и ожидаемые результаты. Материалы и методы. READIT-2020 (Russian prospective study of REduction And DIscontinuation Treatment of TKI) — российское проспективное нерандомизированное клиническое исследование, главная цель которого — разработка схемы безопасного ведения больных ХМЛ с БМО и ГМО, получающих сниженные дозы ИТК, с последующим наблюдением в период РБЛ под контролем минимальной остаточной болезни. В исследование планируется включить 100 пациентов. На каждом из этапов клинического исследования предусмотрен регулярный молекулярно-генетический мониторинг в центральной лаборатории (ФГБУ «НМИЦ гематологии» Минздрава России, Москва). Первичная задача заключается в оценке выживаемости без потери БМО (BCR-ABL > 0,1 %) как при терапии ИТК в сниженных дозах, так и в период РБЛ. Первичная конечная точка — период наблюдения 12 мес. после отмены ИТК.

Background. A withdrawal of tyrosine kinase inhibitor (TKI) therapy in chronic myeloid leukemia (CML) patients with optimal response, especially in patients with drug toxicity, is a matter of current interest. According to the results of numerous clinical studies, the probability of sustaining treatment-free remission (TFR) in CML patients with deep molecular response (DMR) is about 40-60 %. Great attention has recently been paid to personalized therapy consisting in TKI dose modification aimed at reducing or preventing therapy adverse events. Many large retrospective studies showed that reduced TKI doses in CML patients with major molecular response (MMR) and DMR is a safe therapy option. The follow-up of patients receiving reduced TKI doses is also carried out under prospective clinical studies as a stage prior to therapy discontinuation. This approach shows that the probability of sustaining TFR after the stage of TKI dose reduction is about 70 % which is higher than that after the withdrawal of standard TKI doses. Aim. To present the background, aim, and mai n objectives of the study as well as the design and expected results. Materials & Methods. READIT-2020 (Russian prospective study of REduction And DIscontinuation Treatment of TKI) is a Russian prospective non-randomized clinical study with the main aim of developing a safe management regimen for CML patients with MMR and DMR, who receive reduced TKI doses, with subsequent follow-up in the period of TFR under the control of minimal residual disease. The study is going to enroll 100 patients. Each stage of the clinical study will include a regular molecular genetic monitoring at the central laboratory (National Research Center for Hematology, Moscow). The primary objective is to assess survival without MMR loss (BCR-ABL > 0.1 %) both on reduced TKI doses and during TFR. The primary endpoint is the follow-up period of 12 months after TKI discontinuation. Trial Registration No.: NCT04578847 (Clinicaltrial.gov).

Multipotent mesenchymal stromal cells (MSC) are the key regulators of hematopoiesis. We studied changes in MSC characteristics in patients with myeloid leukemia and patients with lymphoproliferative diseases. MSC were obtained from the bone marrow of patients at the time of diagnostic puncture using a standard technique. Their proliferative potential and expression of genes associated with differentiation and regulation of hematopoiesis were studied. The total cell production of MSC in patients with leukemia at the onset of the disease did not differ from that in the group of healthy donors. The relative expression of the IL6, TGFb1 and TGFb2, PPARG genes was similar in all patients. The relative expression of the JAG1, LIF, IGF1, CSF1, IL1b, and IL1bR1 genes in MSC of patients with leukemia was enhanced and the relative expression of SDF1 was unchanged in comparison with MSC from donors. MSC from patients with leukemia were characterized by enhanced relative expression of PDGFRA and PDGFRB, and reduced expression of SOX9. Changes functions of the stromal microenvironment in patients with hemoblastoses attested to the role of stromal cells in the maintenance and spread of tumor cells.

Therapy with tyrosine kinase inhibitors (TKI) allows to achieve a deep molecular response in 6070% of patients with chronic myeloid leukemia (CML). According to the current guidelines CML patients receive a long-term treatment with TKI in standard dose. The frequently observed adverse effects (AE) of TKI therapy are mostly dose-dependent. A new treatment approach with TKI use in reduced dose is desirable for the CML patients with existing AE or with a high risk of AE occurrence. We report the two cases of successful long-term treatment of CML patients with reduced doses of second generation TKIs. The aim of the TKI dose reduction was to reduce the clinical manifestations of drug toxicities and to prevent the AE.

Introduction. The pathogenesis of myeloproliferative neoplasms is associated with the chimeric gene BCR-ABL1 or with one of the driver mutations in the genes JAK2, MPL and CALR (Calreticulin). However, the classifi cation of the World Health Organization lists no myeloid neoplasms with more than one driver genetic abnormality. Aim. To search for mutations in the genes JAK2, MPL and CALR in patients with BCR-ABL1-positive chronic myeloid leukemia (CML), as well as to evaluate the kinetics of the discovered mutations during tyrosine kinase inhibitor (TKI) therapy. Materials and methods. mRNA and DNA samples isolated from blood and bone marrow cells of 567 CML patients, who underwent periodic monitoring of the BCR-ABL1 transcript level over the 2012–2019 period were included in the study The BCR-ABL1 transcript level was determined using a highly sensitive quantitative real-time polymerase chain reaction. The mutations JAK2V617F and MPLW515L/K were detected using real-time quantitative allele-specifi c polymerase chain reaction. Mutations in the CALR gene were investigated using fragment analysis followed by Sanger sequencing. Results. The combination of the BCR-ABL1, JAK2 and CALR gene mutations among CML patients receiving TKIs was 1.23 % (7/567). Out of these, the combination of BCR-ABL1 with JAK2V617F and the combination of BCR-ABL1 with CALR gene mutations were detected in 0.88 % (5/567) and 0.35 % (2/567) of cases, respectively. During TKI therapy, in 5 out of 7 patients, the level of BCR-ABL1 reached major molecular response (MR). In 4 of these patients, the therapy was discontinued. These patients are currently in molecular remission. In the remaining 2 patients, major MR was not achieved, despite the use of second-generation TKI preparations. Conclusions. The combination of the BCR-ABL1 chimeric gene with gene mutations Jak2 or CALR was a rare event and amounted to 0.88 and 0.35 % of cases, respectively. The combination of BCR-ABL1 with Jak2V617F and CALR mutations does not always impede the achievement of major MR.

Introduction . The advent of tyrosine kinase inhibitors (TKIs) in clinical practice drastically improved prognosis in patients with chronic myeloid leukaemia (CML). Adverse events of the TKI therapy and its high financial burden warrant the trend to gradually abandon this treatment. Aim . To assess the results of CML patient monitoring after the withdrawal of TKI therapy. Patients and methods . This prospective study included 98 chronic phase CML patients satisfying the criteria: any receiving of TKI therapy for ≥3 years; deep molecular response (DMR, BCR-ABL ≤ 0.01 % IS) during ≥ 2 years. The withdrawal was followed by quantitative BCR-ABL estimation performed monthly for the first 6 months of the survey, bimonthly for 1 year and every 3 months from the second year onwards. Therapy was resumed at a loss of major molecular response (MMR, BCR-ABL ≥ 0.1 % IS). Results . The MMR loss upon the TKI withdrawal was observed in 48 (49 %) patients. Survival without MMR loss was 52 % past 24 months since withdrawal, with a median of 35 months (23–52). The duration of therapy, MR and the MR depth at the time of withdrawal significantly correlated with a conserved post-therapy MMR. Gender, age, a Sokal risk group, type and line of TKI therapy at withdrawal, and imatinib resistance in history were not observed to significantly impact molecular relapse-free remission. MMR was recovered in all 48 patients with TKI therapy resumed in molecular relapse. In 65 % of the patients, adverse therapy events observed during treatment completely resolved by 6 months of post-therapy monitoring. Musculoskeletal pain (withdrawal syndrome, WS) was reported in 42 % patients in the post-therapeutic period, which did not lead to TKI resumption. The WS development correlated with an elder age and longer therapy prior to withdrawal. Conclusion . Molecular relapse-free survival in CML patients with treatment-free remission (TFR) is comparable to other published evidence. Monitoring safety during TFR is attested by the lack of disease progression and MMR recovery upon TKI resumption in all patients.

Хронический миелоидный лейкоз (ХМЛ) - онкогематологическое заболевание. Благодаря разработке таргетных препаратов ингибиторов тирозинкиназ (ИТК) достигнуты большие успехи в лечении ХМЛ, однако около 20-40% пациентов резистентны к терапии. Цель исследования - обнаружение экзомных вариантов, обуславливающих различную эффективность терапии ХМЛ. Нами было проведено севенирование экзома 60 пациентов, страдающих ХМЛ, на платформе Illumina NextSeq® 550 Sequencing System. Были обнаружены варианты в генах ASXL1, DNMT3A в группе пациентов, резистентных к терапии ИТК. Выявленные варианты могут быть ассоциированы с резистентностью к терапии ИТК. Chronic myeloid leukemia (CML) is an oncohematological disease. Great success has been achieved in the treatment of CML due to the development of targeted drugs for tyrosine kinase inhibitors (TKI), but about 20-40% of patients are resistant to therapy. The aim of the study was the detection of exome variants causing resistance to CML therapy. We examined the exomes of 60 CML patients using the Illumina NextSeq® 550 Sequencing System platform. In the group of patients resistant to TKI therapy, loss-of-function variants were revealed in the ASXL1 and DNMT3A genes. Identified variants may be associated with resistance to TKI therapy.

Introduction. BCR-ABL tyrosine kinase inhibitors are currently used to successfully treat chronic myeloid leukemia (CML). Drug therapy is carried out in a continuous daily mode throughout the patient’s life. Treatment with this group of drugs is associated with specific dermatological adverse events (dAE), which can lead to a change in the regimen of effective, vital therapy for CML patients.Purpose. To study the characteristics of dermatological adverse events, the severity and influence on the quality of life of BCR-ABL tyrosine kinase inhibitors.Patients and methods. The observational study included 93 patients. The clinical manifestations of dAE, their severity were evaluated, their photographs and pathomorphological studies of skin biopsy samples were performed, cases of dose reduction or drug withdrawal due to dAE were recorded. The quality of life of patients with dAE was determined based on the assessment of the dermatological index of quality of life.Results. Imatinib therapy was accompanied by a maculopapular rash in 43.3 % of patients, nilotinib caused follicular keratosis in 12.9 % of patients. In 3.2 % of patients, dasatinib caused hyperpigmentation, in 2.2 % of patients lichenoid rashes of the II degree occurred during treatment with bosutinib. Ponatinib treatment was followed by dAE in 9.7 % of patients. All dAE have an impact on the quality of life of patients, but the maculopapular rash and dyskeratotic changes are most pronounced. In a pathomorphological study, these dAE have specific features corresponding to immuno-mediated dermatitis.Conclusions. The most frequent and pronounced dAE that significantly affect the quality of life of patients with CML are a maculopapular rash and dyskeratotic skin changes: psoriasiform and lichenoid dermatitis. Clinical and pathomorphological characteristics of skin reactions make it possible in the future to determine effective methods of supportive therapy for dAE.

Introduction. The pathogenesis of myeloproliferative neoplasms is associated with the chimeric gene BCR-ABL1 or with one of the driver mutations in the genes JAK2, MPL and CALR (Calreticulin). However, the classifi cation of the World Health Organization lists no myeloid neoplasms with more than one driver genetic abnormality. Aim. To search for mutations in the genes JAK2, MPL and CALR in patients with BCR-ABL1-positive chronic myeloid leukemia (CML), as well as to evaluate the kinetics of the discovered mutations during tyrosine kinase inhibitor (TKI) therapy. Materials and methods. mRNA and DNA samples isolated from blood and bone marrow cells of 567 CML patients, who underwent periodic monitoring of the BCR-ABL1 transcript level over the 2012–2019 period were included in the study The BCR-ABL1 transcript level was determined using a highly sensitive quantitative real-time polymerase chain reaction. The mutations JAK2V617F and MPLW515L/K were detected using real-time quantitative allele-specifi c polymerase chain reaction. Mutations in the CALR gene were investigated using fragment analysis followed by Sanger sequencing. Results. The combination of the BCR-ABL1, JAK2 and CALR gene mutations among CML patients receiving TKIs was 1.23 % (7/567). Out of these, the combination of BCR-ABL1 with JAK2V617F and the combination of BCR-ABL1 with CALR gene mutations were detected in 0.88 % (5/567) and 0.35 % (2/567) of cases, respectively. During TKI therapy, in 5 out of 7 patients, the level of BCR-ABL1 reached major molecular response (MR). In 4 of these patients, the therapy was discontinued. These patients are currently in molecular remission. In the remaining 2 patients, major MR was not achieved, despite the use of second-generation TKI preparations. Conclusions. The combination of the BCR-ABL1 chimeric gene with gene mutations Jak2 or CALR was a rare event and amounted to 0.88 and 0.35 % of cases, respectively. The combination of BCR-ABL1 with Jak2V617F and CALR mutations does not always impede the achievement of major MR.

Aim. Based on our own materials to characterize the clinical manifestations of hypereosinophilic states distinguishing between reactive eosinophilia (RE), clonal myeloproliferative neoplasms with eosinophilia (MPN-eo), and myeloproliferative variant of hypereosinophilic syndrome (MP-HES); to evaluate treatment results. Materials & Methods. The trial included 188 patients with primary HES (132 men and 56 women, aged 19-72 years) having been followed-up at the National Research Center for Hematology since 2001. The main entry criteria were blood eosinophilia > 1.5 x 109/L and clinical symptoms resulting sometimes from hypereosinophilia. All patients received complete physical examination, immunomorphological, standard cytogenetic, and molecular genetic testing. Treatment was provided to 73 patients (63 men and 10 women) including those with MPN-eo PDGFRA+ (п = 39), PDGFRB+ (п = 2), FGFR1+ (п = 1), chronic eosinophilic leukemia not otherwise specified (п = 8), systemic mastocytosis (п = 1), and MP-HES (п = 22). Complete hematological response (CHR) was the criterion for treatment efficacy. In the MPN-eo PDGFRA+ and PDGFRB+ groups molecular response (MR) rate was also estimated in cases of imatinib treatment. MR was considered as no expression of the FIP1L1-PDGFRA and ETV6-PDGFRB transcripts in RT-PCR. Results. The trial yielded the cause of eosinophilia in 117 (62.2 %) out of 188 patients. RE was diagnosed in 60 (32 %) out of 117 patients, various types of clonal MPNs were reported in 57 (30 %) patients. In 71 (38 %) out of 188 patients HES was still present at the first trial stages. Later within this group MP-HES was identified in 22 (30.9 %) out of 71 patients. Among imatinib recipients CHR was achieved in 37 (90 %) out of 41 patients within 1-3 months: in 36 patients with MPN-eo FIP1L1-PDGFRA+ and in 1 patient with MPN-eo ETV6-PDGFRB+. MR was achieved in 88 % of cases. In the absence of molecular markers characteristic of MPN-eo CHR was achieved in 26 % of cases. Among the recipients of treatments other than imatinib nobody achieved CHR. Conclusion. The diagnosis approach in patients with HES should be complex and individualized. Development and enhancement of molecular genetic diagnostic techniques are regarded as ones of the highest priority areas in modern hematology. The use of imatinib mesylate in MPN-eo therapy commonly results in long-term hematological and molecular remissions. On achieving CHR to imatinib treatment of patients without molecular markers characteristic of MPN-eo early use of this drug (or other tyrosine kinase inhibitors) can be recommended in acute forms of HES.

Background.The European Population Register EUTOS for CML includes data on adult patients (n = 2904) diagnosed with Ph-positive (Ph+) and/or BCR-ABL1-positive (BCR-ABL1+) chronic myeloid leukemia (CML) in 20 European countries during the period from 2008 to December 2012. Russia took part in this study, having contributed 6.8 % of CML patients to the total number of patients in the Register.Aim.To estimate long-term treatment outcomes in patients with newly diagnosed CML in the Russian Federation in comparison with the data obtained for a pan-European population cohort of patients.Patients and methods.The cohort under study consisted of 197 patients from 6 Russia regions, all of whom were diagnosed with a Ph+ / BCR-ABL1 + CML during the period from October, 1, 2009 to December, 31, 2012. The patients’ median age was 50 (18–82) years, with men and women being represented in approximately equal proportions.Results.In the first line, 97 % and 3 % of the patients received Imatinib and 2nd generation tyrosine kinase (TKI) inhibitors, respectively. The response dynamics was as follows: 12 months after the treatment, a complete cytogenetic response and a major molecular response were achieved in 40 % and 20 % of the patients. The overall survival (OS) and progression-free survival rates in patients in Russia following 12, 24 and 30 months were 93 %, 87 % and 84 %, and 92 %, 87 % and 87 %, respectively. In Russia, the study was prolonged. By 80 months of observation, the OS of patients in the chronic CML phase with a low and high risk of the disease progression had been 88 % and 56 %, respectively. In the acceleration phase, the 5-year overall survival rate was 39 %.Conclusion.An analysis of treatment outcomes in CML patients in a population-based non-selected sample indicates an increase in the survival of CML patients. However, problematic aspects of the therapy have been identified, along with a need for intensification of the treatment in patients with an unfavourable CML prognosis.

We analyzed changes in multipotent mesenchymal stromal cells of patients with chronic myeloid leukemia before discontinuation of tyrosine kinase inhibitors. Withdrawal syndrome was significantly more common in patients who have been taking tyrosine kinase inhibitors for a longer time and in patients of older age and with lower body weight. In patients with withdrawal syndrome, the total production of mesenchymal stromal cells and expression of FGFR2 and MMP2 genes were significantly lower; loss of deep molecular response was also less frequent in this group of patients. At the same time, the expression of genes important for the maintenance of stem cells (SOX9, PDGFRa, and LIF) was significantly lower in the mesenchymal stromal cells of patients with withdrawal syndrome and loss of deep molecular response. We observed a clear-cut relationship between the development of withdrawal syndrome and the loss of deep molecular response. The decrease in the expression of FGFR2 and MMP2 genes in the mesenchymal stromal cells of patients with chronic myeloid leukemia before discontinuation of treatment can be a predictor of withdrawal syndrome, while simultaneous decrease in the expression of SOX9, PDGFRa, and LIF in these cells attests to undesirability of therapy discontinuation at the moment.

Introduction. The properties of progenitor cells in the stromal microenvironment, i.e. multipotent mesenchymal stromal cells (MMSC) and fi broblast colony-forming units (CFU-F), undergo changes in patients with chronic myelogenous leukaemia (CML).Aim. To compare the progenitor cells of the stromal microenvironment (MMSCs and CFU-Fs) obtained from the bone marrow of CML patients at the onset of the disease, one year after the start of the treatment and during the long-term treatment with tyrosine kinase inhibitors (TKI).Materials and methods. The study involved an analysis of the characteristics of MMSCs, the concentration of CFU-Fs in the bone marrow of CML patients, as well as the relative expression level of genes (REL) associated with differentiation and involved in the regulation of haematopoiesis. The analysis was performed at the onset of the disease, one year after the start of the treatment, as well as 3–8 and 9–16 years after the TKI therapy. MMSCs and CFU-Fs of healthy donors were used for control purposes.Results. The concentration of CFU-Fs at the onset of the disease did not differ from that in donors; however, the relative expression level of genes associated with differentiation was increased in the CFU-F colonies. A year after the start of TKI treatment, the concentration of CFU-Fs decreased by four times. Subsequently, the concentration increased to reach normal values following 8 years of TKI treatment. The total production of MMSCs was not changed at the onset of the disease; however, it decreased after a year of TKI treatment, subsequently returning to normal. The expression of many genes was altered in the MMSCs of patients, i.e. the REL of LIF and JAG1 increased by 10 and 2 times, respectively; in the course of treatment, the REL of LIF in MMSCs decreased, always remaining higher than in those of the donors, whereas the expression of JAG1 returned to normal. At the onset of the disease, the REL of LIF in the MMSCs of patients, who achieved a deep molecular response (DMR) within 17 months of the treatment, was three times lower than in the MMSCs of those patients who did not reach DMR within 50 months, with JAG1 not differing from that of donors.Conclusion. Changes in stromal progenitor cells are associated with the influence of tumour cells, as well as with TKI therapy. A normal expression level of JAG1 and a decreased expression level of LIF in the MMSCs of CML patients at the onset of the disease may be predictive of DMR achievement.Conflict of interest: the authors declare no conflict of interest.Financial disclosure: the study had no sponsorship.

Background. Chronic myeloid leukemia (CML) is a common myeloproliferative disease characterized by pathologic activity of the fusion gene BCR/ABL, which encodes a tyrosine kinase that stimulates uncontrolled cell proliferation and DNA instability. Up to 20% of CML patients demonstrate primary resistance or non-optimal response to targeted tyrosine-kinase inhibitors (TKI) therapy. Objective. To find new potential genetic markers of TKI resistance by whole exome sequencing. Materials and methods. The study included eight patients with Ph+ CML in the chronic phase (CF). After 6 months of follow-up period patients were divided into two groups: four with an optimal response to TKI therapy and four with a non-optimal response. The validation group included 62 patients (32 with optimal and 30 with non-optimal response to therapy). Exome sequencing was performed using the Ion Torrent PGM platform. Alignment was performed on the human genome (GRCh37). Sanger sequencing was conducted on an ABI PRISM 3500xl. Statistical processing of the results was carried out using MS Office Excel and SPSS21. Results and conclusion. Exome sequencing revealed seven single-nucleotide variants (SNVs) associated with therapy outcomes: ANKRD35-rs11579366, DNAH9-rs 1990236, MAGEC1-rs 176037, TOX3-rs10653661, THSD1-rs3803264, MORN2-rs3099950, and PTCRA-rs9471966. Validation of these variants in 62 patients did not confirm prognostic role of any of the individual SNVs or their combinations. An additional analysis of the number of SNVs in 9000 genes revealed 75 genes with significant differences in the number of SNVs. Enrichment analysis showed that these genes are involved in cell adhesion, cell contacts, T-cell antigen activation, and inhibition of IFN alpha-mediated antiproliferative signaling. Many of these genes are also associated with a variety of cancers (renal, lung and breast cancer). Possible multifactorial nature of the efficacy of therapy complicates the search of new prognostic markers.

This article is the 4th edition of the recommendations for the diagnosis and treatment of chronic myeloid leukemia. The group of authors reviewed and discussed relevant new publications, and included the significant remarks and comments of experts. Particular attention was paid to the control of risk factors for the development of arterial vascular events and their prevention, and adverse effects of the long-term therapy with tyrosine kinase inhibitors, which were being increasingly reported in recent years.