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.

Aim. To study the impact of different clinical and biological factors on sustaining molecular remission after discontinuation of tyrosine kinase inhibitors (TKI) therapy in chronic myeloid leukemia (CML) patients with a stable deep molecular response (MR). Materials & Methods. The prospective multi-center trial on molecular remission sustainability after TKIs withdrawal, held from 2015 to 2019, enrolled 98 CML patients. The trial included patients with chronic phase CML treated with TKIs at least during 3 years and having a stable deep MR (< МО4; BCR-ABL < 0.01 %) during at least 2 years. Molecular monitoring was carried out every month during first 6 months after TKIs withdrawal, every 2 months during 0.5-1 year, and every 3 months after 1-year follow-up. In case of the loss of major MR (BCR-ABL > 0.1 %) therapy was reinitiated. Results. Three-year molecular relapse-free survival was 51 % (95% confidence interval 41-61 %) in all patients, 25 % in patients with the failure of prior treatment discontinuation, and 53 % in patients who discontinued TKI therapy for the first time. According to univariate analysis, the following factors proved to be significant: persistance of deep MR, duration of therapy, and depth of MR. It was shown that TKI therapy duration, but not deep MR persistance, has independent prognostic value for the Russian population of CML patients. No significant differences were identified in 3-year molecular relapse-free survival in the groups of patients treated only with imatinib (55 %) compared with patients who received 2nd generation TKI (TKI2) as first-line (70 %; p = 0.26) and second-line (39 %; p = 0.09) therapy. However, duration of therapy in patients treated with TKI2 as first-line therapy was more than twice as short as in patients treated with imatinib as first-line therapy (median 41.5 vs. 96.4 months, respectively; p < 0.0001). Conclusion. Longer therapy duration and MR depth (< M04.5) before TKI withdrawal raise the probability of sustaining off-treatment remission. The study showed that molecular relapse-free survival does not significantly increase with the use of TKI2 as first-line treatment compared to imatinib. Nevertheless, TKI2 as first-line treatment enables to halve the duration of therapy needed to achieve comparable molecular relapse-free survival, as compared with imatinib.

Цель. Изучить влияние различных клинических и биологических факторов на сохранение молекулярной ремиссии после отмены терапии ингибиторами тирозинкиназ (ИТК) у пациентов с хроническим миелолейкозом (ХМЛ) со стабильным глубоким молекулярным ответом (МО). Материалы и методы. С 2015 по 2019 г. в проспективное многоцентровое исследование по оценке стабильности молекулярной ремиссии после прекращения приема ИТК включено 98 пациентов с ХМЛ. В исследование включали пациентов в хронической фазе ХМЛ, с длительностью терапии ИТК ≥ 3 лет и стабильным глубоким МО (≤ МО4; BCR-ABL < 0,01 %) в течение по крайней мере 2 лет. Молекулярный мониторинг проводили ежемесячно в течение первых 6 мес. после отмены ИТК, каждые 2 мес. в течение 0,5–1 года и каждые 3 мес. после 1 года наблюдения. Возобновление лечения требовалось в случае потери большого МО (BCR-ABL > 0,1 %). Результаты. 3-летняя выживаемость без молекулярного рецидива составила 51 % (95%-й доверительный интервал 41–61 %) во всей группе, 25 % у пациентов с неудачной попыткой отмены терапии в анамнезе и 53 % у пациентов, прекративших прием ИТК впервые. По результатам однофакторного анализа статистически значимыми оказались следующие факторы: длительность глубокого МО, длительность терапии и глубина МО. Показано, что длительность терапии ИТК, а не длительность глубокого МО имеет независимое прогностическое значение для российской популяции пациентов с ХМЛ. Не выявлено статистически значимых различий в 3-летней выживаемости без молекулярного рецидива в группах пациентов, получавших только иматиниб (55 %), по сравнению с пациентами, получавшими ИТК 2-го поколения (ИТК2) в первую (70 %; p = 0,26) и вторую линии лечения (39 %; p = 0,09). Тем не менее длительность терапии у пациентов, получавших ИТК2 в качестве первой линии, была более чем в 2 раза меньше, чем у пациентов, получавших иматиниб в первой линии (медиана 41,5 vs 96,4 мес. соответственно; p < 0,0001). Заключение. Более длительная продолжительность лечения и глубина МО (≤ MО4.5) до отмены ИТК увеличивают вероятность сохранения ремиссии без лечения. Наше исследование показало, что выживаемость без молекулярного рецидива значимо не увеличивается при применении ИТК2 в первой линии по сравнению с иматинибом. Тем не менее терапия ИТК2 в качестве первой линии позволяет сократить вдвое длительность лечения, необходимого для достижения сопоставимых показателей выживаемости без молекулярного рецидива по сравнению с иматинибом.

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.

Background. Current clinical guidelines on diagnosis and treatment of chronic myeloid leukemia (CML) define indications for substitution of first-line tyrosine kinase inhibitor (TKI) at therapy failure during different phases of disease progression. Aim. To assess the efficacy of CML treatment with implementing the protocol of timely monitoring and switching to another TKI. Materials & Methods. Patients were included into pilot prospective study РИТМ during 5 years. Data on 100 CML patients were analyzed. Therapy and monitoring were conducted according to the Federal clinical guidelines on CML diagnosis and therapy, 2013. Results. Median follow-up after initiation of treatment was 46 months (range 12-74). Imatinib mesylate was administered as first-line therapy to 91 (91 %) patients, 9 (9 %) patients received 2nd generation TKI (TKI2). Therapy failure was registered in 31 (31 %) patients; 26 (84 %) of them were switched to TKI2. At the time of analysis 95 (95 %) patients were followed-up. Cumulative incidence of CML-associated mortality was 2 %. By the fifth year of follow-up cumulative probability of complete cytogenetic, major and deep molecular responses was 93 %, 88 % and 66 %, respectively. Conclusion. CML treatment according to current guidelines yields the results comparable with those achieved by first-line TKI2 therapy. This approach reduces CML treatment costs and lowers the risk of TKI2-associated adverse events. Due to a high rate of deep molecular response the proportion of CML patients in remission without treatment can be increased in the future.

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.

Aim. To analyze adverse cardiovascular events in chronic myeloid leukemia (CML) patients who received various tyrosine kinase inhibitors (TKI). Materials & Methods. The trial included 97 CML patients with nilotinib, dasatinib or imatinib indications. By the time of examination the patients had undergone TKI therapy for 1-138 months. The three of them were sequentially treated with 2 drugs over the monitoring period. All CML patients were aged 22-79 years (median 53.5 years): 55 women were aged 22-71 years (median 53.5 years) and 42 men were aged 24-79 years (median 53 years). Results. The comparative analysis demonstrated significantly higher impact of nilotinib on daily maximum QTc duration compared with other TKIs. The patients who received nilotinib (n = 15) throughout 38 months had QTc of 0.47 s (interquartile range [IQR] 0.46-0.47 s), in imatinib group (n = 17) QTc was 0.43 s (IQR 0.43-0.44 s), and in dasatinib group (n = 4) QTc was 0.43 s (IQR 0.42-0.44 s) (p = 0.0008). Among all patients treated with nilotinib there were 62 % (31/50) with QTc > 0.46 s, in imatinib (6/41) and dasatinib (2/18) groups it was detected in 14.6 % and 11.1 % of patients, respectively (p = 0.0008). Five patients had QTc > 0.48 s, which is the criterion for discontinuation of treatment or dose reduction. In two patients the identified changes of QTc duration required TKI temporary suspension. After nilotinib dose reduction or discontinuation QTc duration normalized in all cases within 2 weeks. Decreased ankle-brachial index (ABI) < 0.9 without pronounced clinical symptoms was identified in two patients who received nilotinib. Afterwards they showed peripheral occlusive disease of lower extremities, and nilotinib treatment was discontinued. In patients treated with other TKIs no occlusive vascular lesions were observed. A case of chronic heart failure with reduced left ventricular ejection fraction developing on nilotinib therapy was revealed and described. Conclusion. Despite high specificity for BCR-ABL tyrosine kinase, new TKIs can, although rarely, induce cardiovascular adverse events. Prior to TKI treatment assignment CML patients should be examined with ECG and EchoCG with systolic function evaluation, and the measurement of pulmonary artery pressure as well as ABI. The examination should be repeated in the end of the 1st year TKI treatment if there is no reason for extra examinations. It is recommended to hold 24-hour ECG monitoring with QTc max measurement prior to nilotinib assignment, then once a year within 2 years of nilotinib treatment, and once in 6 months after 3 years of therapy.

Aim. To assess the results of following up patients with chronic myeloid leukemia (CML) and a deep molecular response (MR) without tyrosine kinase inhibitor (TKI) therapy. Subjects and methods. The reasons for TKI discontinuation in 70 patients with CML and a deep MR of more than 1 year’s duration were adverse events, pregnancy, and patients’ decision. Information was collected retrospectively and prospectively in 2008-2016. Results. The median follow-up after TKI therapy discontinuation was 23 months (2 to 100 months). At 6, 12 and 24 months after TKI therapy discontinuation, the cumulative incidence of major MR (MMR) loss was 28, 41 and 48%, respectively; the survival rates without TKI therapy were 69, 50, and 39%, respectively. MMR loss was noted in 28 (88%) patients at 12 months; it was not seen without TKI therapy at 2-year follow-up. Deaths due to CML progression were absent. The Sokal risk group was a reliable factor influencing MMR loss (p ≤ 0.05). The cumulative recovery rate for deep MR after resumption of TKI use was 73 and 100% at 12 and 24 months, respectively, with a median follow-up of 24 months (1 to 116 months). Deep MR recovered at a later time when the therapy was resumed more than 30 days after MMR loss. Conclusion. Safe follow-up is possible in about 50% of the patients with CML and stable deep MRs without TKI therapy. The introduction of this approach into clinical practice requires regular molecular genetic monitoring and organizational activities. Biological factors in maintaining remission after TKI discontinuation need to be separately studied.

Nilotinib (AMN 107, Tasigna (R), Novartis Pharma, Switzerland), is 2-nd line Bcr/Abl-tyrosine kinase inhibitor (TKI2). Nilotinib is characterized by the highest selective activity in comparison with all TKI. Nilotinib has low active or inert towards other tyrosine kinases and involves a lesser risk of side effects associated with inhibition of non-target proteins. Clinically this is confirmed by the absence of life-threatening symptoms in the patients treated with nilotinib. Nilotinib are not cross-toxic wit imatinib. The strict adhering to the treatment protocol regulations - an Obligatory condition to minimize the uncontrolled changes in plasma nilotinib concentrations, which can lead, in turn, to toxicity or reduction of the drug effect. These regulations are oral dose taken strictly after fasting, special care in combined treatment with the drugs modulating the cytochrome system activity and the drugs modulating the ECG QT interval. A characteristic feature of nilotinib toxicity profile is rare incidence of untoward phenomena, manifesting by clinical symptoms, and rather high incidence of deviations in laboratory values. Practical recommendations on the treatment strategy in patients with undesirable symptoms, such as rash, itching, hyperbilirubinemia, hyperglycemia, high amylase and lipase levels, QTcF interval prolongation, and in CML patients who wish to have children are presented.