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Abstract: Secondary kinase domain mutations in BCR::ABL1 represent the most common cause of resistance to tyrosine kinase inhibitor (TKI) therapy in patients with chronic myeloid leukemia. The first 5 approved BCR::ABL1 TKIs target the adenosine triphosphate (ATP)-binding pocket. Mutations confer resistance to these ATP-competitive TKIs and those approved for other malignancies by decreasing TKI affinity and/or increasing ATP affinity. Asciminib, the first highly active allosteric TKI approved for any malignancy, targets an allosteric regulatory pocket in the BCR::ABL1 kinase C-lobe. As a non-ATP-competitive inhibitor, the activity of asciminib is predicted to be impervious to increases in ATP affinity. Here, we report several known mutations that confer resistance to ATP-competitive TKIs in the BCR::ABL1 kinase N-lobe that are distant from the asciminib binding pocket yet unexpectedly confer in vitro resistance to asciminib. Among these is BCR::ABL1 M244V, which confers clinical resistance even to escalated asciminib doses. We demonstrate that BCR::ABL1 M244V does not impair asciminib binding, thereby invoking a novel mechanism of resistance. Molecular dynamic simulations of the M244V substitution implicate stabilization of an active kinase conformation through impact on the α-C helix as a mechanism of resistance. These N-lobe mutations may compromise the clinical activity of ongoing combination studies of asciminib with ATP-competitive TKIs., (© 2024 American Society of Hematology. Published by Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.)

Asciminib targets the BCR::ABL1 myristoyl pocket, maintaining activity against BCR::ABL1 T315I , which is resistant to most approved adenosine triphosphate-competitive tyrosine kinase inhibitors. We report updated phase I results (NCT02081378) assessing safety/tolerability and antileukemic activity of asciminib monotherapy 200 mg twice daily in 48 heavily pretreated patients with T315I-mutated chronic-phase chronic myeloid leukemia (CML-CP; data cutoff: January 6, 2021). With 2 years' median exposure, 56.3% of patients continued receiving asciminib. Overall, 62.2% of evaluable patients achieved BCR::ABL1 ≤1% on the International Scale (IS); 47.6% and 81.3% of ponatinib-pretreated and -naive patients, respectively, achieved BCR::ABL1 IS  ≤1%. Of 45 evaluable patients, 48.9% achieved a major molecular response (MMR, BCR::ABL1 IS  ≤0.1%), including 34.6% and 68.4% of ponatinib-pretreated and -naive patients, respectively. MMR was maintained until data cutoff in 19 of 22 patients who achieved it. The most common grade ≥3 adverse events (AEs) included increased lipase level (18.8%) and thrombocytopenia (14.6%). Five (10.4%) patients experienced AEs leading to discontinuation, including 2 who discontinued asciminib and died due to COVID-19; these were the only deaths reported. These results show asciminib's effectiveness, including in almost 50% of ponatinib pretreated patients, and confirm its risk-benefit profile, supporting its use as a treatment option for T315I-mutated CML-CP., (© 2024. The Author(s).)

Purpose of Review: The discovery that patients suffering from chronic myeloid leukemia who obtain deep and long-lasting molecular responses upon treatment with tyrosine kinase inhibitors may maintain their disease silent for many years after therapy discontinuation launched the era of treatment-free remission as a key management goal in clinical practice. The purpose of this review on treatment-free remission is to discuss clinical advances, highlight knowledge gaps, and describe areas of research., Recent Findings: Patients in treatment-free remission are a minority, and it is believed that some may still retain a reservoir of leukemic stem cells; thus, whether they can be considered as truly cured is uncertain. Strengthening BCR::ABL1 inhibition increases deep molecular responses but is not sufficient to improve treatment-free remission, and we lack biomarkers to identify and specifically target residual cells with aggressive potential. Another level of complexity resides in the intra- and inter-patient clonal heterogeneity of minimal residual disease and characteristics of the bone marrow environment. Finding determinants of deep molecular responses achievement and elucidating varying biological mechanisms enabling either post-tyrosine kinase inhibitor chronic myeloid leukemia control or relapse may help develop innovative and safe therapies. In the light of the increasing prevalence of CML, targeting the residual leukemic stem cell pool is thought to be the key., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Patients with chronic myeloid leukaemia in chronic phase (CML-CP) who have a sustained deep molecular response (DMR) are eligible to discontinue treatment and attempt treatment-free remission (TFR). In the DASFREE study (ClinicalTrials.gov; NCT01850004), the 2-year TFR rate after dasatinib discontinuation was 46%; here we present the 5-year update. Patients with a stable DMR after ≥2 years of dasatinib therapy discontinued treatment and were followed for 5 years. At a minimum follow-up of 60 months, in 84 patients discontinuing dasatinib, the 5-year TFR rate was 44% (n = 37). No relapses occurred after month 39 and all evaluable patients who relapsed and restarted dasatinib (n = 46) regained a major molecular response in a median of 1.9 months. The most common adverse event during the off-treatment period was arthralgia (18%, 15/84); a total of 15 withdrawal events were reported in nine patients (11%). At the 5-year final follow-up, almost half of the patients who discontinued dasatinib after a sustained DMR maintained TFR. All evaluable patients who experienced a relapse quickly regained a DMR after restarting dasatinib, demonstrating that dasatinib discontinuation is a viable and potentially long-term option in patients with CML-CP. The safety profile is consistent with the previous report., (© 2023 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Molecular recurrence (MRec) occurs in about half of all patients with chronic myeloid leukaemia (CML) who discontinue tyrosine kinase inhibitors (TKI) in sustained deep molecular response. A second TKI discontinuation has been attempted in some patients who regain the discontinuation criteria after resuming treatment. Nilotinib treatment affords faster and deeper molecular responses than imatinib as first-line therapy. We prospectively evaluated the efficacy and safety of nilotinib (300 mg twice daily) in chronic-phase CML patients who experienced MRec, after imatinib discontinuation and analysed the probability of TFR after a new attempt in patients treated for 2 years with sustained MR 4.5 for at least 1 year. A total of 31 patients were included in the study between 2013 and 2018. Seven (23%) patients experienced serious adverse events after a median of 2 months of nilotinib treatment leading to discontinuation of treatment. One patient was excluded from the study for convenience. Among the 23 patients treated for 2 years with nilotinib, 22 maintained their molecular response for at least 1 year (median: 22 months) and stopped nilotinib. The TFR rates at 24 and 48 months after nilotinib discontinuation were 59.1% (95% confidence interval [CI]: 41.7%-83.7%) and 42.1% (95% CI: 25%-71%) respectively (NCT #01774630)., (© 2023 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

The paradigm for managing patients with chronic myeloid leukemia is evolving. In the recent past, restoring a normal life expectancy while patients are receiving never-ending targeted therapy with BCR-ABL1 tyrosine kinase inhibitors through prevention of progression to blast phase and mitigation of iatrogenic risks was considered the best achievable outcome. Now, long-term treatment-free remission with continued response off tyrosine kinase inhibitor therapy is recognized as the most optimal benefit of treatment. Indeed, numerous independent clinical trials provided solid proof that tyrosine kinase inhibitor discontinuation was feasible in patients with deep and sustained molecular responses. This article discusses when tyrosine kinase inhibitors may be safely stopped in clinical practice on the basis of the best and latest available evidence., Competing Interests: Conflict-of-interest disclosure: D.R. has received honoraria from and served on advisory boards for Pfizer, Novartis, and Incyte and has been a member of clinical trial steering committees for Bristol Myers Squibb and Novartis., (© 2020 by The American Society of Hematology.)

Purpose of Review: Treatment goals and ambitions have even been upwardly revised since demonstration was made that under certain conditions, treatment-free remission was possible. Herein, we will discuss on how to try tailoring treatment choices to the unique characteristics of each patient., Recent Findings: Since the first-generation ATP-competitive TKI imatinib was made available in the clinic in 2001, second-generation drugs such as dasatinib, nilotinib and bosutinib and the third-generation TKI ponatinib have broadened the therapeutic armamentarium, providing effective salvage against intolerance and different types of resistance, or as frontline options. Management and outcomes of patients with chronic myeloid leukemia have been revolutionized by the discovery, development, and approval of BCR-ABL tyrosine kinase inhibitors (TKIs). Most patients can now expect a near-to normal life expectancy and acceptable quality of life on life-long treatment, providing awareness and avoidance of harmful adverse events, which depend on each TKI safety profile and patient personal background.

Purpose: Tyrosine kinase inhibitor (TKI) discontinuation is an emerging goal in chronic myelogenous leukemia (CML) management and several studies have demonstrated the feasibility of safely stopping imatinib. A sustained deep molecular response on long-term TKI is critical prior to attempting treatment-free remission. Reproducible results from several studies reported recently, failed to identify robust and reproducible predictive factors for the selection of the best candidates for successful TKI cessation., Patients and Methods: We conducted a prospective national phase II study evaluating the cessation of imatinib after at least 2 years of MR4.5 obtained on imatinib first-line in patients with chronic phase CML., Results: A total of 218 patients with de novo chronic phase CML were involved in the study. The median follow-up after imatinib cessation was 23.5 (1-64) months, 2 patients died from unrelated causes, and 107 experienced a confirmed increase in BCR-ABL1 levels defined as molecular recurrence. The molecular recurrence-free survival was 52% [95% confidence interval (CI), 45%-59%] at 6 months, and 50% (95% CI, 43%-57%) at 24 months. Droplet digital PCR (ddPCR) was used to evaluate more accurately low levels of BCR-ABL1 in 175 of 218 patients at imatinib cessation. To apply positive BCR-ABL1/ABL1 ratios on the international scale (IS), a conversion factor was calculated for ddPCR and the significant cut-off point was established at 0.0023% IS . In a multivariate analysis, the duration of TKI (≥74.8 months) and ddPCR (≥0.0023% IS ) were the two identified predictive factors of molecular recurrence, with P = 0.0366 (HR, 0.635; 95% CI, 0.415-0.972] and P = 0.008 (HR, 0.556; 95% CI, 0.360-0.858), respectively., Conclusions: We conclude that the duration of TKI and residual leukemic cell load as determined by ddPCR are key factors for predicting successful treatment-free remission for patients with de novo chronic phase CML. See related commentary by Yan et al., p. 6561 ., (©2019 American Association for Cancer Research.)

Chronic myeloid leukemia (CML) has become a chronic disease, for which the chronic phase is manageable with tyrosine kinase inhibitor (TKI) therapy. Patients with optimal responses to TKIs have achieved long-term survival, and treatment-free remission (TFR) has since become an additional treatment goal in CML. In this review, we discuss important factors to consider prior to stopping treatment. In addition, published and presented data with the first-generation TKI imatinib, as well as current clinical trials evaluating TFR with the second-generation TKIs dasatinib and nilotinib, are examined. Results obtained outside of clinical trials have been included as well. Because successful TKI discontinuation depends upon accurate BCR-ABL1 monitoring, emerging technologies are also discussed. Clinical data obtained to date indicate that for many patients who achieve deep molecular response (DMR) on TKI therapy, TFR is a safe treatment goal, and, if the response is lost, patients can expect to regain their responses immediately upon reinitiation of TKI. It is also clear that there remains much room for improvement to make TFR a successful reality for most patients. Data from ongoing trials should help refine decisions as to which patients are the best candidates to attempt TKI discontinuation with safe monitoring in place., (© 2018 The Authors. American Journal of Hematology published by Wiley Periodicals, Inc.)

Ponatinib represents a remarkable progress in the treatment of heavily pretreated chronic myelogenous leukemia (CML) and de novo Philadelphia chromosome-positive ALL patients despite significant toxicity in clinical trials. To date, "real-life" data remain few and the use of ponatinib in this setting and its consequences remain mostly unknown. We report, within a national observational study, the use of ponatinib in unselected CML patients who had previously failed ≥2 lines of tyrosine kinase inhibitor (TKI) therapy (or one line if an Abelson (ABL) T315I mutation was identified), in real-life conditions (2013-2014) in a compassionate program. Our analysis has been focused on 48 chronic phase CML patients recorded. With a median follow-up of 26.5 months since ponatinib initiation, the overall survival (OS) rates (80.5% at 3 years) and cumulative incidence of major molecular response (81.8% at 18 months) were similar to those of the phase II study, with no influence of BCR-ABL mutations nor the reason of ponatinib prescription. A specific subanalysis of the preexisting cardiovascular risk factors and events occurring on ponatinib is described. These events occurred after a median time on ponatinib of 5.8 months (excluding hypertension) and were observed in 29/48 patients (47%), even in those already on anti-aggregants/coagulants. The majority were not severe and resolved, but two cases were fatal. Other hematological or nonhematological nonvascular adverse events were similar to those previously described in trials. This observational study reports similar rates of survival, molecular responses, and a slight increase in the cardiovascular toxicity of ponatinib in real-life conditions, prompting improved control of cardiovascular risk factors and selection of patients., (Copyright © 2018 ISEH -- Society for Hematology and Stem Cells. Published by Elsevier Inc. All rights reserved.)

Background: The ultimate goal of chronic myeloid leukemia management in the tyrosine kinase inhibitor (TKI) era for patients who obtain deep molecular responses is maintaining a durable off-treatment response after treatment discontinuation; this situation is called treatment-free remission (TFR). Knowledge accumulated during the last 10 years justifies moving TFR strategies from research to clinical practice., Methods: Twenty experts from the French Chronic Myeloid Leukemia Study Group (France Intergroupe des Leucémies Myéloïdes Chroniques), including 17 hematologists, 2 molecular biologists, and 1 cytogeneticist, critically reviewed published data with the goal of developing evidence-based recommendations for TKI discontinuation in clinical practice., Results: Clinically relevant questions were addressed, including the selection of candidate patients (with known prognostic factors for outcomes taken into account), detailed monitoring procedures during the treatment-free phase, a definition of relapse requiring therapy resumption, and monitoring after treatment reintroduction., Conclusions: This work presents consensus statements with the aim of guiding physicians and biologists by means of pragmatic recommendations for safe TKI discontinuation in daily practice. Cancer 2018;124:2956-63. © 2018 American Cancer Society., (© 2018 American Cancer Society.)

Background: Several studies have demonstrated that approximately one-half of patients with chronic myeloid leukemia (CML) who receive treatment with tyrosine kinase inhibitors (TKIs) and achieve and maintain a deep molecular response (DMR) are able to successfully discontinue therapy. In patients who have a molecular relapse, a DMR is rapidly regained upon treatment re-initiation., Methods: The authors report the results from RE-STIM, a French observational, multicenter study that evaluated treatment-free remission (TFR) in 70 patients who re-attempted TKI discontinuation after a first unsuccessful attempt. After the second TKI discontinuation attempt, the trigger for treatment re-introduction was the loss of a major molecular response in all patients., Results: The median follow-up was 38.3 months (range, 4.7-117 months), and 45 patients (64.3%) lost a major molecular response after a median time off therapy of 5.3 months (range, 2-42 months). TFR rates at 12, 24, and 36 months were 48% (95% confidence interval [CI], 37.6%-61.5%), 42% (95% CI, 31.5%-55.4%), and 35% (95% CI, 24.4%-49.4%), respectively. No progression toward advanced-phase CML occurred, and no efficacy issue was observed upon TKI re-introduction. In univariate analysis, the speed of molecular relapse after the first TKI discontinuation attempt was the only factor significantly associated with outcome. The TFR rate at 24 months was 72% (95% CI, 48.8%-100%) in patients who remained in DMR within the first 3 months after the first TKI discontinuation and 36% (95% CI, 25.8%-51.3%) for others., Conclusions: This study is the first to demonstrate that a second TKI discontinuation attempt is safe and that a first failed attempt at discontinuing TKI does not preclude a second successful attempt. Cancer 2017;123:4403-10. © 2017 American Cancer Society., (© 2017 American Cancer Society.)

Purpose: Achievement of deep molecular response with a tyrosine kinase inhibitor in patients with chronic myeloid leukemia (CML) is required to attempt discontinuation of therapy in these patients. The current subanalysis from the Evaluating Nilotinib Efficacy and Safety in Clinical Trials as First-Line Treatment (ENEST1st) study evaluated whether age has an impact on the achievement of deeper molecular responses or safety with frontline nilotinib in patients with CML., Methods: ENEST1st is an open-label, multicenter, single-arm, prospective study of nilotinib 300 mg twice daily in patients with newly diagnosed CML in chronic phase. The patients were stratified into the following 4 groups based on age: young (18-39 years), middle age (40-59 years), elderly (60-74 years), and old (≥75 years). The primary end point was the rate of molecular response 4 ([MR 4 ] BCR-ABL1 ≤0.01% on the international scale) at 18 months from the initiation of nilotinib., Results: Of the 1091 patients enrolled, 1089 were considered in the analysis, of whom, 23% (n = 243), 45% (n = 494), 27% (n = 300), and 5% (n = 52) were categorized as young, middle age, elderly, and old, respectively. At 18 months, the rates of MR 4 were 33.9% (95% confidence interval [CI], 27.8-40.0%) in the young, 39.6% (95% CI, 35.3-44.0%) in the middle-aged, 40.5% (95% CI, 34.8-46.1%) in the elderly, and 35.4% (95% CI, 21.9-48.9%) in the old patients. Although the incidence of adverse events was slightly different, no new specific safety signals were observed across the 4 age groups., Conclusions: This subanalysis of the ENEST1st study showed that age did not have a relevant impact on the deep molecular response rates associated with nilotinib therapy in newly diagnosed patients with CML and eventually on the eligibility of the patients to attempt treatment discontinuation.

STOP second generation (2G)-tyrosine kinase inhibitor (TKI) is a multicenter observational study designed to evaluate 2G-TKI discontinuation in chronic myeloid leukemia (CML). Patients receiving first-line or subsequent dasatinib or nilotinib who stopped therapy after at least 3 years of TKI treatment and in molecular response 4.5 (MR4.5) with undetectable BCR-ABL1 transcripts for the 2 preceding years at least were eligible for inclusion. This interim analysis reports outcomes of 60 patients with a minimum follow-up of 12 months (median 47, range: 12-65). Twenty-six patients (43.3%) experienced a molecular relapse defined as the loss of a major molecular response (MMR). Relapses occurred after a median time of 4 months (range: 1-38). Cumulative incidences of molecular relapse by 12 and 48 months were 35% (95% confidence interval [CI], 24.79% to 49.41%) and 44.76% (95% CI, 33.35% to 59.91%), respectively. Treatment-free remission (TFR) rates at 12 and 48 months were 63.33% (95% CI, 51.14% to 75.53%) and 53.57% (95% CI, 40.49% to 66.65%), respectively. In univariate analysis, prior suboptimal response or TKI resistance was the only baseline factor associated with significantly worse outcome. A landmark analysis demonstrated that loss of MR4.5 3 months after stopping TKI was predictive of failure to maintain MMR later on. During the treatment-free phase, no progression toward advanced phase CML occurred, and all relapsing patients regained MMR and MR4.5 after restarting therapy. In conclusion, discontinuation of first-line or subsequent 2G-TKI yields promising TFR rates without safety concerns. Further research is encouraged to better define conditions that will offer patients the highest chance to remain free from 2G-TKI therapy., (© 2017 by The American Society of Hematology.)

Purpose Imatinib (IM) can safely be discontinued in patients with chronic myeloid leukemia (CML) who have had undetectable minimal residual disease (UMRD) for at least 2 years. We report the final results of the Stop Imatinib (STIM1) study with a long follow-up. Patients and Methods IM was prospectively discontinued in 100 patients with CML with UMRD sustained for at least 2 years. Molecular recurrence (MR) was defined as positivity of BCR-ABL transcript in a quantitative reverse transcriptase polymerase chain reaction assay confirmed by a second analysis point that indicated an increase of one log in relation to the first analysis point at two successive assessments or loss of major molecular response at one point. Results The median molecular follow-up after treatment discontinuation was 77 months (range, 9 to 95 months). Sixty-one patients lost UMRD after a median of 2.5 months (range, 1 to 22 months), and one patient died with UMRD at 10 months. Molecular recurrence-free survival was 43% (95% CI, 33% to 52%) at 6 months and 38% (95% CI, 29% to 47%) at 60 months. Treatment was restarted in 57 of 61 patients with MR, and 55 patients achieved a second UMRD with a median time of 4 months (range, 1 to 16 months). None of the patients experienced a CML progression. Analyses of the characteristics of the study population identified that the Sokal risk score and duration of IM treatment were significantly associated with the probability of MR. Conclusion With a median follow-up of more than 6 years after treatment discontinuation, the STIM1 study demonstrates that IM can safely be discontinued in patients with a sustained deep molecular response with no late MR.

Tyrosine kinase inhibitors targeting the BCR-ABL oncoprotein represent an outstanding progress in chronic myeloid leukemia and long-term progression-free survival has become a reality for a majority of patients. However, tyrosine kinase inhibitors may at best chronicize rather than cure the disease thus current recommendation is to pursue treatment indefinitely. As a consequence, high quality treatment and care must integrate optimal disease control and treatment tolerability. Tyrosine kinase inhibitors have an overall favorable safety profile in clinical practice since most adverse events are mild to moderate in intensity. However, recent evidence has emerged that new generation tyrosine kinase inhibitors may sometimes damage vital organs and if not adequately managed, morbidity and mortality may increase. The 2nd generation tyrosine kinase inhibitor nilotinib is licensed for the treatment of chronic myeloid leukemia with resistance or intolerance to imatinib and newly diagnosed chronic phase-chronic myeloid leukemia. Nilotinib represents an important therapeutic option but it is associated with an increased risk of cardiovascular events. The purpose of this article by the France Intergroupe des Leucémies Myéloïdes Chroniques is to provide an overview of nilotinib efficacy and cardiovascular safety profile and to propose practical recommendations with the goal to minimize the risk and severity of cardiovascular events in nilotinib-treated patients., (Copyright © 2015 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.)

The prognosis of most leukemia patients treated with BCR-ABL tyrosine kinase inhibitors (TKIs) is favorable, and a more precise understanding of serious and potentially irreversible treatment-related toxicities is essential to properly inform treatment choice. Few cases of pulmonary arterial hypertension (PAH) have been reported in patients with leukemia treated with dasatinib, a second-generation BCR-ABL TKI. To better understand characteristics and outcomes of dasatinib-treated patients with PAH, all clinical cases of PAH confirmed by right-heart catheterization in the Bristol-Myers Squibb pharmacovigilance database (N = 41), including 22 previously unpublished cases, were examined for previous treatments for leukemia, patient characteristics, time to PAH onset, and outcomes. Our analysis shows that compared with PAH due to other etiologies, dasatinib-related PAH is atypical, in that it is associated with partial to complete reversibility upon treatment discontinuation. The incidence of dasatinib-related PAH appears to be low. Most PAH cases were observed in patients who had received prior treatments for leukemia. No specific patient attributes appear to be associated with an increased risk of developing PAH while receiving dasatinib. Symptoms of PAH in dasatinib-treated leukemia patients should prompt a thorough workup, including consideration of confirmatory right-heart catheterization. In cases of confirmed PAH, dasatinib should be discontinued., (© 2015 Wiley Periodicals, Inc.)

Tyrosine kinase inhibitors (TKIs) targeting the breakpoint cluster region-Abelson 1 (BCR-ABL1) oncoprotein represent an outstanding progress in chronic myeloid leukemia (CML), and long-term survival has become a reality. However, the majority of patients need to be treated during their entire life span; thus, outcome does not solely depend on treatment efficacy but also on how well therapy is tolerated. TKIs have an overall favorable safety profile in clinical practice. Although many patients may encounter adverse events, these usually occur early after treatment initiation, are mild to moderate in intensity and resolve spontaneously, or are easily controlled with adequate supportive care. Whenever treatment interruption is necessary, re-exposition to the same TKI or switch to an alternative TKI is successful in the majority of the cases. However, long-term safety issues have not been fully elucidated at present, especially for new-generation TKIs. Recent evidence has emerged that these new agents may sometimes impinge on vital organs such as the heart and lung in an irreversible fashion especially when comorbidities are present; thus, decision regarding of which TKI should be used must take into account disease-related, TKI-related, and patient-related variables. The purpose of this article is to provide an up-to-date review of common adverse events associated with TKIs and how these events may be optimally managed.

The second-generation tyrosine kinase inhibitor (TKI) of the BCR-ABL1 oncoprotein nilotinib used in patients with chronic myeloid leukemia is suspected to increase the risk of arterial occlusion, especially in patients with pre-existing cardiovascular risk factors or established cardiovascular diseases. Here, we describe a case of unexpected and rapid onset of symptomatic peripheral artery disease (PAD) associated with silent stenosis of digestive and renal arteries in a nilotinib-treated patient devoid of significant cardiovascular diseases (CVD) risk factor, prior atherosclerotic disease, or other cause of arterial damage. This is the first report to establish a direct relationship between nilotinib exposure and PAD and to reveal that arterial damage is irreversible despite rapid drug withdrawal. However, functional outcome was favorable upon rapid TKI replacement, specific cardiovascular disease management, and development of collateral arterial network., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Vascular safety is an emerging issue in patients with chronic myeloid leukemia (CML) treated with tyrosine kinase inhibitors (TKIs). Whereas imatinib exhibits a well-documented and favorable long-term safety profile without obvious accumulation of vascular events, several types of vascular adverse events (VAEs) have been described in patients receiving second- or third-generation BCR/ABL1 TKIs. Such VAEs include pulmonary hypertension in patients treated with dasatinib, peripheral arterial occlusive disease and other arterial disorders in patients receiving nilotinib, and venous and arterial vascular occlusive events during ponatinib. Although each TKI interacts with a unique profile of molecular targets and has been associated with a unique pattern of adverse events, the mechanisms of drug-induced vasculopathy are not well understood. Here, recent data and concepts around VAEs in TKI-treated patients with CML are discussed, with special reference to potential mechanisms, event management, and strategies aimed at avoiding occurrence of such events in long-term treated patients., (© 2015 by The American Society of Hematology.)

Patients in complete cytogenetic response (CCyR) with detectable BCR-ABL1 after ≥2 years on imatinib were randomized to nilotinib (400 mg twice daily, n = 104) or continued imatinib (n = 103) in the Evaluating Nilotinib Efficacy and Safety in clinical Trials-Complete Molecular Response (ENESTcmr) trial. By 1 and 2 years, confirmed undetectable BCR-ABL1 was achieved by 12.5% vs 5.8% (P = .108) and 22.1% vs 8.7% of patients in the nilotinib and imatinib arms, respectively (P = .0087). Among patients without molecular response 4.5 (BCR-ABL1(IS) ≤0.0032%; MR(4.5)) and those without major molecular response at study start, MR(4.5) by 2 years was achieved by 42.9% vs 20.8% and 29.2% vs 3.6% of patients in the nilotinib and imatinib arms, respectively. No patient in the nilotinib arm lost CCyR, vs 3 in the imatinib arm. Adverse events were more common in the nilotinib arm, as expected with the introduction of a new drug vs remaining on a well-tolerated drug. The safety profile of nilotinib was consistent with other reported studies. In summary, switching to nilotinib enabled more patients with chronic myeloid leukemia in chronic phase (CML-CP) to sustain lower levels of disease burden vs remaining on imatinib. This trial was registered at www.clinicaltrials.gov as #NCT00760877., (© 2014 by The American Society of Hematology.)

Despite a well-recognized clinical benefit of the 2(nd)-generation tyrosine kinase inhibitor nilotinib in patients with imatinib-resistant/-intolerant or newly diagnosed chronic myeloid leukemia, recent evidence suggests that nilotinib has a propensity to increase the risk of occlusive arterial events, especially in patients with pre-existing cardiovascular risk factors. Given the key role of lipids in cardiovascular diseases, we studied the plasma lipid profile and global cardiovascular risk prior to and during nilotinib therapy in a series of 27 patients in the setting of a prospective single center study. Data from a minimum 1-year follow up showed that nilotinib significantly increased total, low- and high-density lipoprotein cholesterol within three months. Consequently, the proportion of patients with non-optimal low-density lipoprotein cholesterol increased from 48.1% to 88.9% by 12 months, leading to cholesterol-lowering drug intervention in 22.2% of patients. The proportion of patients with low levels of high-density lipoprotein cholesterol decreased from 40.7% to 7.4% by 12 months. In contrast, a significant decrease in triglycerides was observed. Global cardiovascular risk worsened in 11.1% of patients due to diabetes or occlusive arterial events. Whether hypercholesterolemia was the main driver of occlusive arterial events was uncertain: a longer follow up is necessary to ask whether nilotinib-induced hypercholesterolemia increases long-term risk of atherosclerotic diseases. Nevertheless, given key atherogenic properties of low-density lipoprotein cholesterol, we conclude that when prescribing nilotinib, commitment to detect lipid disorders at baseline and during follow up is mandatory given their frequency, requirement for changes in lifestyle or drug intervention, and potential for long-term cardiovascular complications., (Copyright© Ferrata Storti Foundation.)

Chronic myeloid leukemia (CML) patients with the BCR-ABL T315I mutation do not benefit from therapy with currently approved tyrosine kinase inhibitors. Omacetaxine mepesuccinate is a protein synthesis inhibitor that has demonstrated activity in cells harboring the T315I mutation. This phase 2 trial assessed the efficacy of omacetaxine in CML patients with T315I and tyrosine kinase inhibitor failure. Patients received subcutaneous omacetaxine 1.25 mg/m(2) twice daily, days 1-14, every 28 days until hematologic response or a maximum of 6 cycles, and then days 1-7 every 28 days as maintenance. Results for patients treated in chronic phase are reported here. Patients (n = 62) received a median of 7 (range, 1-41) cycles. Complete hematologic response was achieved in 48 patients (77%; 95% lower confidence limit, 65%); median response duration was 9.1 months. Fourteen patients (23%; 95% lower confidence limit, 13%) achieved major cytogenetic response, including complete cytogenetic response in 10 (16%). Median progression free-survival was 7.7 months. Grade 3/4 hematologic toxicity included thrombocytopenia (76%), neutropenia (44%), and anemia (39%) and was typically manageable by dose reduction. Nonhematologic adverse events were mostly grade 1/2 and included infection (42%), diarrhea (40%), and nausea (34%). Omacetaxine may provide a safe and effective treatment for CML patients with T315I mutation. This study is registered at www.clinicaltrials.gov as NCT00375219.

Ensuring adherence to therapy is a challenge in chronic diseases, particularly in cancers such as chronic myeloid leukemia (CML), where there has been increased availability and use of oral formulations. A conceptual model of adherence was developed based on findings from a comprehensive literature review, to inform strategies for improving adherence to oral CML therapies. A complex interplay of factors (including clinical, psychological and behavioural) influence adherence to such therapies. Healthcare professionals have a key role in promoting and facilitating adherence and future strategies should place greater emphasis on understanding patient-level experiences in order to create personalized solutions., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The use of tyrosine kinase inhibitors (TKIs) targeted against the BCR-ABL1 oncoprotein has proven remarkably successful in chronic myeloid leukemia (CML) and long-term survival has become a reality. Despite this outstanding progress, detection of minimal residual disease precludes therapy termination in most TKI-receiving patients. CML has thus turned into a chronic illness, raising concerns about long-term safety, medication adherence, and health care costs. Although treatment cessation may be feasible in few selected patients achieving deep molecular responses, a definitive cure remains elusive owing to the discovery that TKIs spare quiescent leukemic stem cells (LSC). Understanding mechanisms underlying LSC behavior in TKI-treated patients may provide important clues to develop an array of strategies that ensure the complete destruction of LSC reservoirs and thereby offer CML patients a definitive cure.

Ponatinib, the only approved all known-BCR::ABL1 inhibitor, is a third-generation tyrosine-kinase inhibitor (TKI) designed to inhibit BCR::ABL1 with or without any single resistance mutation, including T315I, and induced robust and durable responses at 45 mg/day in patients with CP-CML resistant to second-generation TKIs in the PACE trial. However, cardiovascular toxicities, including arterial occlusive events (AOEs), have emerged as treatment-related AEs within this class of TKIs. The OPTIC trial evaluated the efficacy and safety of ponatinib using a novel, response-based, dose-reduction strategy in patients with CP-CML whose disease is resistant to ≥2 TKIs or who harbor T315I. To assess the dose-response relationship and the effect on the safety of ponatinib, we examined the outcomes of patients with CP-CML enrolled in PACE and OPTIC who received 45 mg/day of ponatinib. A propensity score analysis was used to evaluate AOEs across both trials. Survival rates and median time to achieve ≤1% BCR::ABL1IS in OPTIC were similar or better than in PACE. The outcomes of patients with T315I mutations were robust in both trials. Patients in OPTIC had a lower exposure-adjusted incidence of AOEs compared with those in PACE. This analysis demonstrates that response-based dosing for ponatinib improves treatment tolerance and mitigates cardiovascular risk.

Dasatinib was approved at 100 mg once daily for imatinib-resistant or -intolerant patients with chronic myeloid leukemia (CML) in chronic phase, based on results of the phase 3 CA180-034 (NCT00123474) study. Here we present the final 7-year analysis of this pivotal study, the longest follow-up to date of any second-generation BCR-ABL1 tyrosine kinase inhibitor (TKI). Patients (n = 670) with imatinib-resistant or -intolerant CML in chronic phase received dasatinib. Nineteen percent of patients continued on study treatment, with a greater proportion in the 100 mg once daily arm remaining on therapy. Seven-year rates for major molecular response (MMR), progression-free survival (PFS), and overall survival (OS) were similar across doses; MMR, PFS, and OS results were 46, 42, and 65% at 100 mg once daily, respectively. Improved PFS and OS rates were reported in patients who achieved BCR-ABL1 ≤10% at 3 and 6 months. No new safety signals were identified. The incidence of drug-related pleural effusion was 28% at 100 mg once daily and 35% at the other three dose groups. Incidence of drug-related pulmonary hypertension and pulmonary arterial hypertension remained low (≤3% across all doses). Arterial ischemic events occurred in ≤4% of patients across all doses. These data support the long-term efficacy and well-established safety profile of dasatinib for patients with imatinib-resistant or -intolerant CML in chronic phase. Am. J. Hematol. 91:869-874, 2016. © 2016 Wiley Periodicals, Inc.

Clinical trials have formally demonstrated that in chronic myeloid leukemia (CML), patients treated with tyrosine kinase inhibitors (TKI) who achieved and maintained deep molecular responses could discontinue their treatment after several years without facing overt signs of disease relapse in approximately 50% of the cases. In patients with a molecular relapse, prompt re-introduction of TKI therapy was able to rapidly restore deep molecular responses. The concept of a lifelong therapy with TKI has thus been challenged and treatment-free remission (TFR) strategies will soon integrate clinical practice, providing that safe recommendations will be established. In this article, we give an update on TKI discontinuation studies in CML and we also provide an overview of upcoming TFR clinical and biological challenges. [ABSTRACT FROM AUTHOR]