Discontinuation of tyrosine kinase inhibitors in chronic myeloid leukemia: Recommendations for clinical practice from the French Chronic Myeloid Leukemia Study Group

Clinical efficacy and safety of first-line nilotinib or imatinib therapy in patients with chronic myeloid leukemia-Nationwide real life data

BACKGROUND

To evaluate the outcomes of first-line imatinib versus nilotinib treatment for chronic myeloid leukemia in the chronic phase (CML-CP) in real-world clinical practice.

METHODS

A propensity score analysis was performed to eliminate imbalances between the treatment groups. In the analysis, 163 patients in the nilotinib group and 163 patients in the matched imatinib group were retrospectively evaluated.

RESULTS

Nilotinib-treated patients achieved complete cytogenetic response (CCyR) and major molecular response more rapidly than imatinib-treated patients. However, there was no significant difference in 5-year overall survival (OS) or progression-free survival (PFS) between the two groups (OS: 94.3% vs. 90.5%, p = 0.602; PFS: 92.9% vs. 88.0%, p = 0.614). Nilotinib-treated patients had a higher failure-free survival (FFS) and event-free survival (EFS) than imatinib-treated patients (FFS: 71.7% vs. 54.3%, p = 0.040; EFS: 71.7% vs. 53.5%, p = 0.025).

CONCLUSIONS

This retrospective analysis from clinical practice did not confirm any benefit of frontline nilotinib treatment for OS and PFS; however, it did demonstrate higher FFS and EFS in the nilotinib cohort.

European Stop Tyrosine Kinase Inhibitor Trial (EURO-SKI) in Chronic Myeloid Leukemia: Final Analysis and Novel Prognostic Factors for Treatment-Free Remission

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.The European Stop Kinase Inhibitors (EURO-SKI) study is the largest clinical trial for investigating the cessation of tyrosine kinase inhibitors (TKIs) in patients with chronic myeloid leukemia in stable deep molecular remission (DMR). Among 728 patients, 434 patients (61%; 95% CI, 57 to 64) remained in major molecular response (MMR) at 6 months and 309 patients of 678 (46%; 95% CI, 42 to 49) at 36 months. Duration of TKI treatment and DMR before TKI stop were confirmed as significant factors for the prediction of MMR loss at 6 months. In addition, the type of BCR::ABL1 transcript was identified as a prognostic factor. For late MMR losses after 6 months, TKI treatment duration, percentage of blasts in peripheral blood, and platelet count at diagnosis were significant factors in multivariate analysis. For the entire study period of 36 months, multiple logistic regression models confirmed duration of treatment, blasts, and transcript type as independent factors for MMR maintenance. In addition to the duration of treatment, transcript type as well as blasts in peripheral blood at diagnosis should be considered as important factors to predict treatment-free remission.

Artificial Intelligence-Based Management of Adult Chronic Myeloid Leukemia: Where Are We and Where Are We Going?

Artificial intelligence (AI) is emerging as a discipline capable of providing significant added value in Medicine, in particular in radiomic, imaging analysis, big dataset analysis, and also for generating virtual cohort of patients. However, in coping with chronic myeloid leukemia (CML), considered an easily managed malignancy after the introduction of TKIs which strongly improved the life expectancy of patients, AI is still in its infancy. Noteworthy, the findings of initial trials are intriguing and encouraging, both in terms of performance and adaptability to different contexts in which AI can be applied. Indeed, the improvement of diagnosis and prognosis by leveraging biochemical, biomolecular, imaging, and clinical data can be crucial for the implementation of the personalized medicine paradigm or the streamlining of procedures and services. In this review, we present the state of the art of AI applications in the field of CML, describing the techniques and objectives, and with a general focus that goes beyond Machine Learning (ML), but instead embraces the wider AI field. The present scooping review spans on publications reported in Pubmed from 2003 to 2023, and resulting by searching "chronic myeloid leukemia" and "artificial intelligence". The time frame reflects the real literature production and was not restricted. We also take the opportunity for discussing the main pitfalls and key points to which AI must respond, especially considering the critical role of the 'human' factor, which remains key in this domain.

How to improve treatment-free remission eligibility in chronic myeloid leukaemia?

The achievement of treatment-free remission (TFR) has become a significant clinical end-point in the management of patients with chronic myeloid leukaemia (CML), providing an opportunity to discontinue therapy with tyrosine kinase inhibitors (TKIs) while maintaining deep molecular response (DMR). Early studies, such as the French STIM trial, have demonstrated that a portion of patients can maintain DMR after treatment cessation, with rates ranging from 40% to 50%, and most relapses occurring within the first 6 months. Key prognostic factors for successful TFR, including treatment duration, duration of DMR, risk scores, and transcript type, have been identified. Optimal patient selection for TFR remains a challenge, but recent research provides insights into potential strategies to increase TFR eligibility. Evidence suggests that early intervention switching to achieve optimal response, treatment combinations, proactive switch in the case of absence of DMR, dose-optimization and induction-maintenance approach can improve molecular responses and, consequently, enhance TFR eligibility. In this review, we report and discuss all the potential therapeutic strategies that may enhance eligibility for a first attempt at TFR, with a particular emphasis on potential future approaches.

The Success of Treatment Free Remission in Chronic Myeloid Leukaemia in Clinical Practice: A Single-Centre Retrospective Experience from South Africa

Introduction

Chronic myeloid leukaemia (CML) management has evolved from a disease once considered to be incurable just over 2 decades ago to that of one of a "functional cure" as defined by the sustained molecular response on stopping tyrosine kinase inhibitor(TKI) therapy. The next goal of CML management has been treatment-free remission (TFR). The past 4 years have seen much international data on TFR attempts in CML in clinical practice. However, Africa as a continent has lagged behind the rest of the world, in keeping up with the latest trends in CML management, and so this study aims to address this gap by assessing the outcome of TFR in CML in a single centre in South Africa (SA).

Methods

We conducted a retrospective cohort study in 12 CML patients in the chronic phase to assess the success of TKI discontinuation. The patients were treated in King Edward VIII Hospital (KEH), a tertiary, academic hospital in KwaZulu-Natal, South Africa, and the study period was from June 2020 to May 2022. Patients included had to have been on TKI therapy for a minimum of 5 years and achieved a deep molecular response (DMR) for a minimum period of 3 years.

Results

The overall TFR cohort showed a success rate of 75% at a median follow-up of 12 months. All patients who failed TFR, defined as a loss of major molecular remission (MMR), failed within 6 months of stopping TKI therapy. All patients who failed TFR regained DMR after retreatment with TKI, with no disease progression reported. The only factor influencing the success of TFR was the total period of TKI therapy.

Conclusion

Despite our study having a small cohort of patients, this study demonstrated that TFR in CML is an attainable goal, even in a resource-limited setting.

First-line second generation tyrosine kinase inhibitors in patients with newly diagnosed accelerated phase chronic myeloid leukemia

Accelerated phase (AP) CML at onset and have poorer prognosis than CP-CML. We hypothesize that off-license use of second generation TKI (TKI2) as front-line therapy might counterbalance this poor prognosis, with limited toxicity. In "real-life" conditions, newly diagnosed patients meeting the ELN cytological criteria for AP-CML or harboring ACA and treated with first-line TKI2 were included in this retrospective multicenter observational study. We enrolled 69 patients [69.5 % male, median age 49.5 years, median follow-up 43.5 months], segregated into hematologic AP [HEM-AP (n = 32)] and cytogenetically defined AP [ACA-AP (n = 37)]. Hematologic parameters were worse in HEM-AP [spleen size (p = 0.014), PB basophils (p < .001), PB blasts (p < .001), PB blasts+promyelocytes (p < .001), low hemoglobin levels (p < .001)]. Dasatinib was initiated in 56 % patients in HEM-AP and in 27 % in ACA-AP, nilotinib in 44 % and 73 % respectively. Response and survival do not differ, regardless of the TKI2: 81 % vs 84.3 % patients achieved CHR, 88 % vs 84 % CCyR, 73 % vs 75 % MMR respectively. The estimated 5-year PFS 91.5 % (95%CI: 84.51-99.06 %) and 5-year OS 96.84 % (95%CI: 92.61-100 %). Only BM blasts (p < 0.001) and BM blasts+promyelocytes (p < 0.001) at diagnosis negatively influenced OS. TKI2 as front-line therapy in newly diagnosed AP-CML induce excellent responses and survival, and counterbalance the negative impact of advanced disease phase.

Importance of TKI treatment duration in treatment-free remission of chronic myeloid leukemia: results of the D-FREE study

Treatment-free remission (TFR) is a new goal for patients with chronic myeloid leukemia in chronic phase (CML-CP) with a sustained deep molecular response (DMR) to treatment with tyrosine kinase inhibitors (TKIs). However, optimal conditions for successful TFR in patients treated with second-generation (2G)-TKIs are not fully defined. In this D-FREE study, treatment discontinuation was attempted in newly diagnosed CML-CP patients treated with the 2G-TKI dasatinib who achieved BCR-ABL1 levels of ≤ 0.0032% (MR4.5) on the international scale (BCR-ABL1IS) and maintained these levels for exactly 1 year. Of the 173 patients who received dasatinib induction therapy for up to 2 years, 123 completed and 60 (48.8%) reached MR 4.5. Among the first 21 patients who maintained MR4.5 for 1 year and discontinued dasatinib, 17 experienced molecular relapse defined as loss of major molecular response (BCR-ABL1IS > 0.1%) confirmed once, or loss of MR4 (BCR-ABL1IS > 0.01%) confirmed on 2 consecutive assessments. The estimated molecular relapse-free survival rate was 16.7% at 12 months. This study was prematurely terminated according to the protocol's safety monitoring criteria. The conclusion was that sustained DMR for just 1 year is insufficient for TFR in CML-CP patients receiving dasatinib for less than a total of 3 years of treatment.

Efficacy and safety of nilotinib in chronic myeloid leukaemia patients who failed to achieve a treatment-free remission period after imatinib discontinuation: Results of the French Nilo post-STIM study

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).

Chronic myeloid leukemia without major molecular response after 2 years of treatment with tyrosine kinase inhibitor

Achieving major molecular response (MMR) with BCR::ABL1 tyrosine kinase inhibitors (TKIs) is associated with lower chances of progression to advanced phase disease and higher chances of treatment-free remission (TFR) in patients with chronic myeloid leukemia (CML). Failure to achieve this molecular milestone after 1 year has been highlighted as "suboptimal" or "warning" sign of treatment failure in CML guidelines and recommendations and implied to predict a poor long-term outcome. In this analysis, we report the long-term outcome of 131 patients who did not achieve MMR within the first 2 years of TKI therapy. Patients who achieved a major cytogenetic response (MCyR; roughly equivalent to BCR::ABL1 transcript levels on the International Scale [IS] <10%) had good long-term overall survival (OS) (10-year OS of 88%) and CML-related overall survival (CML-OS) (10-year CML-OS of 95%). The achievement of MCyR within the first 2 years of treatment predicted a better OS (HR = 0.43, p = .03). The value of MMR was even less pronounced among patients aged 60 years or older at diagnosis, in whom mortality was primarily due to comorbidities unrelated to CML (10-year OS of 55% vs. 10-year CML-OS of 100%). In conclusion, achievement of MCyR within 2 years is a reasonable milestone in CML, and these patients can still have good outcomes even when MMR is not achieved.

SOHO State of the Art Updates and Next Questions | Update on Treatment-Free Remission in Chronic Myeloid Leukemia (CML)

Tyrosine kinase inhibitor (TKI) discontinuation, also known as treatment-free remission (TFR) is currently one of the main goals of chronic myeloid leukemia (CML) therapy. TKI discontinuation should be considered in eligible patients for several reasons. Specifically, TKI therapy is associated with reduced quality of life, long-term side effects, and a heavy financial burden on both the patients and society. TKI discontinuation is a particularly important goal for younger patients diagnosed with CML because of the treatment's effects on their growth and development in addition to potential long-term side-effects. Numerous studies with thousands of patients have demonstrated the safety and feasibility of attempting TKI discontinuation in a select group of patients who have achieved a sustained deep molecular remission. With current TKIs, approximately 50% of patients will be eligible for attempting TFR of which only 50% will achieve a successful TFR. Therefore, in reality, only 20% of patients with newly diagnosed CML will achieve a successful TFR, and the majority of patients will need to continue TKI therapy indefinitely. However, several ongoing clinical trials are investigating treatment options for patients to achieve deeper remission with the ultimate goal of a cure, which is defined as being off drug with no evidence of disease.

Real-world therapeutic response and tyrosine kinase inhibitor discontinuation in chronic phase-chronic myeloid leukemia: data from the French observatory

Guidelines for tyrosine kinase inhibitor (TKI)-treated chronic phase-chronic myeloid leukemia (CML) management are essentially based on data from clinical research trials; however, real-world data should be valuable for optimizing such recommendations. Here, we analyzed the data collected in the French CML Observatory database, a multicenter real-world cohort (n = 646), using a first-line "intention-to-treat" analysis strategy. This cohort included patients treated with first-line imatinib (n = 484), nilotinib (n = 103), dasatinib (n = 17), imatinib and interferon (n = 9), or second-generation (2G)-TKIs and interferon (n = 29). The cumulative incidence of major molecular response (MMR), MR4, MR4.5 and MR5 confirmed the faster response kinetics with 2G-TKIs. Multivariate analysis identified being a woman and residual disease at month 6 as the main predictive factors of deep molecular response (DMR). Moreover, 30% of patients met the criteria for treatment discontinuation (5 years of treatment and ≥ 2 years of DMR), but only 38% of them stopped treatment. Among the 92 patients who actually discontinued treatment due to optimal response, 31.5% relapsed (48% of them after > 6 months of TKI discontinuation). Multivariate analysis identified age and TKI duration as factors positively correlated with treatment-free remission maintenance. Late (> 6 months) relapses were more frequent in patients with the e14a2 BCR::ABL transcript. Relapse rate was higher in patients who stopped TKI before than after 5 years of treatment (52.6% vs 26%; p = 0.040). These results advocate caution concerning early treatment withdrawal, including in patients receiving 2G-TKIs. This still recruiting database is a valuable source of information for the real-world follow-up of patients with CML.

Tyrosine Kinase Inhibitor discontinuation in Chronic Myeloid Leukemia: eligibility criteria and predictors of success

TKI discontinuation proved to be safe and feasible in patients with CML with deep and durable molecular responses, introducing an additional treatment goal for these patients beyond overall survival. However, treatment interruption is a safe procedure only with appropriate patient selection and monitoring. Clinical and biological factors associated with better outcomes do not yet offer a precise stratification of patients according to their risk of relapse. This article aims at reviewing the leading studies present in the field in order to define eligibility criteria for discontinuation and predictors of success.

Treatment-free remission in patients with chronic myeloid leukemia following the discontinuation of tyrosine kinase inhibitors

Tyrosine kinase inhibitors (TKIs) discontinuation in patients with Philadelphia-chromosome-positive chronic myeloid leukemia (Ph-positive CML) is increasingly considered. We aim to evaluate the outcome of patients with CML who discontinued TKIs, and determine the factors associated with differences in the success rates of treatment-free remission (TFR). Patients with Ph-positive CML treated between October 1999 and February 2017 who discontinued therapy were analyzed. A major molecular response (MMR) was defined as BCR-ABL1/ABL1 ratio on the International Scale ≤0.1%. TFR failure was defined as the loss of MMR on any single test. We analyzed TFR rates according to duration and depth of response, and conducted a multivariate analysis for factors associated with loss of MMR. Two-hundred and eighty-four patients were analyzed; 199 patients (70%) electively discontinued TKIs. At a median follow-up of 36 months (95% confidence interval, 32-40) after TKI discontinuation, 53 patients (19%) lost MMR. The estimated 5-year TFR rate was 79%. All but one patient regained MMR after resuming therapy. The estimated 5-year TFR rates were higher with MR⁴ and MR^4.5 ≥5 years, compared with MR⁴ <5 years (87% vs. 92% vs. 64%; p < .0001). By multivariate analysis, only the duration of MR⁴ or MR^4.5 ≥5 years before stopping treatment was associated with a lower risk of loss of MMR. In summary, TFR is safe and feasible in patients with Ph-positive CML on TKI therapy. Achieving MR⁴ or MR^4.5 for at least 5 years is correlated with a better outcome.

South African study of blast phase chronic myeloid leukaemia: A poor prognostic outlook

Background

Chronic myeloid leukaemia (CML) is a haematological malignancy characterised by the translocation t(9;22)(q34;q11.2), resulting in a constitutively active tyrosine kinase. Globally, overall survival of blast crisis phase (BC) CML is one year. Newer tyrosine kinase inhibitors and allogeneic stem cell transplantation offer remission; however, refractory and relapsed disease remain the biggest challenges.

Objective

In South Africa, literature is lacking on BC-CML. This study aimed to determine the disease characteristics and overall survival in South Africa.

Methods

This retrospective, laboratory-based study reviewed all new BC-CML diagnoses via flow cytometry at Charlotte Maxeke Johannesburg Academic Hospital in Johannesburg, South Africa, between April 2016 and October 2019. BC-CML was defined as the presence of > 20% blasts with a CML history or the BCR-ABL1 fusion gene (p210/p190) in the appropriate clinical or pathological context. Survival outcomes were inferred from clinical and laboratory data.

Results

Twenty-two new cases of BC-CML were diagnosed (median age: 34 years). There were 20 (91%) cases with the fusion transcripts p210 and two (9%) cases with p190 BCRABL1. For blast lineage, 14 cases were myeloid (63.6%), six were lymphoid (27.3%), and two were ambiguous (9.1%). There was a 72.7% mortality (16 cases); sepsis, refractory and relapsed disease were the major causes. Patients who achieved remission had lower blast percentages, simple karyotypes, and a trend towards higher white cell and platelet counts at presentation.

Conclusion

Optimised management of early-stage CML, prevention and aggressive management of sepsis, with advocation for newer therapies are needed to improve the overall survival of BC-CML in South Africa.

Kinetics of early and late molecular recurrences after first-line imatinib cessation in chronic myeloid leukemia: updated results from the STIM2 trial

Discontinuation of tyrosine kinase inhibitors in chronic phase chronic myeloid leukemia is feasible in clinical practice based on recently published international recommendations. Nevertheless, factors predictive of molecular recurrence have not been fully elucidated and long-term follow-up of patients enrolled in clinical studies are required in order to update knowledge on discontinuation attempts particularly in terms of the safety and durability of treatment-free remission (TFR). In the current study, we updated results from the STIM2 study in the light of the consensual criterion of molecular recurrence reported in different international recommendations. Among the 199 patients included in the perprotocol study, 108 patients lost a major molecular response. With a median follow-up of 40.8 months (5.5-111 months), the probability of treatment-free remission was 43.4% [36.3-50.4] at 5 years, 40.9% [32.8-47.3] at 7 years and 34.5% [25.6- 43.3] at 9 years. Molecular recurrence occurred between 0 to 6 months, 6 to 24 months and after 24 months in 75 patients (69%), 15 patients (14%) and 18 patients (17%), respectively. Notably, the kinetics of molecular recurrence differed significantly between these three subgroups with a median time from loss of MR4 (BCR::ABL1 IS≤0.01%) to loss of major molecular response of 1, 7 and 22 months, respectively. Predictive factors of molecular recurrence differed according to the time of occurrence of the molecular recurrence. Durations of imatinib treatment and deep molecular response as well as BCR::ABL1/ABL1 levels at cessation of tyrosine kinase inhibitor treatment, as quantified by reverse transcriptase droplet digital polymerase chain reaction, are involved in molecular recurrence occurring up to 24 months but not beyond. (ClinicalTrial. gov Identifier NCT#0134373).

Impact of the treatment of chronic myeloid leukaemia by tyrosine-kinase inhibitors on sick leaves refund: a nationwide cohort study

BACKGROUND

The advent of chronic myeloid leukaemia (CML) tyrosine-kinase inhibitors (TKI) has led to new paradigms including occupational rehabilitation.

OBJECTIVES

This study aimed to characterize the impact of CML treatment on sick leaves within the 2 years following diagnosis in working-age patients.

METHODS

A cohort of all 18-60-year-old newly diagnosed CML patients initiating a TKI between January 1^st 2011 and December 31^st 2014 in France was identified in the French National Healthcare database (Système National des Données de Santé [SNDS]). Patients with a sick leave identified in the 24 months after TKI initiation were compared with sex and initiation date matched controls in a nested case-control design. Factors associated with sick leaves were identified through a conditional logistic regression model, providing adjusted odds-ratio (OR) with their 95% confidence interval (CI).

RESULTS

Among 646 18-60-year-old patients, 268 were prescribed at least one sick leave in the study period, with 176 (27.2%) having their first sick leave prescribed after TKI initiation. The median number of sick days over the 2-years period was 115 per patient (interquartile range 25.5-384.5). In the nested case-control study (176 cases and 176 matched controls), sick leaves were more likely observed with second generation TKI (OR 4.11 [1.80-9.38]), whereas they were less likely observed in case if social deprivation (OR 0.07 [0.02-0.28].

CONCLUSION

More than 25% of working-age CML patients had at least one sick leave within 2 years of TKI initiation, with a higher impact of second generation TKI, and with a median duration of 115 days.

Treatment-free remission in patients with chronic myeloid leukemia: recommendations of the LALNET expert panel

Discontinuing TKIs in LA is the new goal, and LALNET TFR recommendations for CML patients are an unmet need.

TFR recommendations adapted to LA needs will make discontinuation feasible and safe in real life in the region.

Tyrosine kinase inhibitors (TKIs) have dramatically changed the survival of chronic myeloid leukemia (CML) patients, and treatment-free remission (TFR) has recently emerged as a new goal of CML treatment. The aim of this work was to develop recommendations for TKI discontinuation in Latin America (LA), outside of clinical trials. A working group of CML experts from LA discussed 22 questions regarding TFR and reached a consensus for TFR recommendations in the region. TFR is indicated in patients in first chronic phase, with typical BCR-ABL transcripts, under TKI treatment of a minimum of 5 years, in sustained deep molecular response (DMR; molecular response 4.5 [MR4.5]) for 2 years. Sustained DMR must be demonstrated on at least 4 international reporting scale quantitative polymerase chain reaction (PCR) tests, separated by at least 3 months, in the immediate prior 2 years. After second-line therapy, TFR is indicated in previously intolerant, not resistant, patients. Molecular monitoring is recommended monthly for the first 6 months, every 2 to 3 months from months 7 to 12, and every 3 months during the second year, indefinitely. Treatment should be reintroduced if major molecular response is lost. Monitoring of withdrawal syndrome, glucose levels, and lipid profile is recommended after discontinuation. After TKI reintroduction, molecular monitoring is indicated every 2 to 3 months until MR4.0 achievement; later, every 3 to 6 months. For the TFR attempt, having standardized and reliable BCR-ABL PCR tests is mandatory. These recommendations will be useful for safe discontinuation in daily practice and will benefit patients who wish to stop treatment in emergent regions, in particular, with TKI-related chronic adverse events.

TKI discontinuation in CML: how do we make more patients eligible? How do we increase the chances of a successful treatment-free remission?

Treatment-free remission (TFR) is a new and significant goal of chronic myeloid leukemia management. TFR should be considered for patients in stable deep molecular response (DMR) after careful discussion in the shared decision-making process. Second-generation tyrosine kinase inhibitors (TKIs) improve the speed of response and the incidence of DMR. Treatment may be changed to a more active TKI to improve the depth of response in selected patients who have not reached DMR. Stem cell persistence is associated with active immune surveillance and activation of BCR-ABL1-independent pathways, eg, STAT3, JAK1/2, and BCL2. Ongoing studies aim to prove the efficacy of maintenance therapies targeting these pathways after TKI discontinuation.

Kinase Inhibition in Relapsed/Refractory Leukemia and Lymphoma Settings: Recent Prospects into Clinical Investigations

Cancer is still a major barrier to life expectancy increase worldwide, and hematologic neoplasms represent a relevant percentage of cancer incidence rates. Tumor dependence of continuous proliferative signals mediated through protein kinases overexpression instigated increased strategies of kinase inhibition in the oncologic practice over the last couple decades, and in this review, we focused our discussion on relevant clinical trials of the past five years that investigated kinase inhibitor (KI) usage in patients afflicted with relapsed/refractory (R/R) hematologic malignancies as well as in the pharmacological characteristics of available KIs and the dissertation about traditional chemotherapy treatment approaches and its hindrances. A trend towards investigations on KI usage for the treatment of chronic lymphoid leukemia and acute myeloid leukemia in R/R settings was observed, and it likely reflects the existence of already established treatment protocols for chronic myeloid leukemia and acute lymphoid leukemia patient cohorts. Overall, regimens of KI treatment are clinically manageable, and results are especially effective when allied with tumor genetic profiles, giving rise to encouraging future prospects of an era where chemotherapy-free treatment regimens are a reality for many oncologic patients.

Treatment-Free Remission in Chronic Myeloid Leukemia: Can We Identify Prognostic Factors?

Simple Summary

Chronic myeloid leukemia (CML) is a blood cancer. Unlike other cancers CML treatment is lifelong and many patients experience side effects. For those patients who respond well to treatment and achieve deep molecular remission, quality of life is impacted because of continuous treatment. In this review, we look at emerging clinical trials which aim to investigate which patients can safely stop treatment. Treatment-free remission is the ultimate goal for CML patients, but there is still a gap in our knowledge as to why some patients can achieve treatment-free remission, while others relapse when treatment is stopped. Here we discuss if there are any prognostic factors that can predict the best candidates who qualify for treatment discontinuation, with a view to keeping them in remission.

Abstract

Following the development of tyrosine kinase inhibitors (TKI), the survival of patients with chronic myeloid leukaemia (CML) drastically improved. With the introduction of these agents, CML is now considered a chronic disease for some patients. Taking into consideration the side effects, toxicity, and high cost, discontinuing TKI became a goal for patients with chronic phase CML. Patients who achieved deep molecular response (DMR) and discontinued TKI, remained in treatment-free remission (TFR). Currently, the data from the published literature demonstrate that 40–60% of patients achieve TFR, with relapses occurring within the first six months. In addition, almost all patients who relapsed regained a molecular response upon retreatment, indicating TKI discontinuation is safe. However, there is still a gap in understanding the mechanisms behind TFR, and whether there are prognostic factors that can predict the best candidates who qualify for TKI discontinuation with a view to keeping them in TFR. Furthermore, the information about a second TFR attempt and the role of gradual de-escalation of TKI before complete cessation is limited. This review highlights the factors predicting success or failure of TFR. In addition, it examines the feasibility of a second TFR attempt after the failure of the first one, and the current guidelines concerning TFR in clinical practice.

Early BCR-ABL1 kinetics are predictive of subsequent achievement of treatment-free remission in chronic myeloid leukemia

With treatment-free remission (TFR) rapidly becoming the ultimate goal of therapy in chronic myeloid leukemia (CML), there is a need to develop strategies to maximize sustained TFR by improving our understanding of its key determinants. Chronic-phase CML patients attempting TFR were evaluated to identify the impact of multiple variables on the probability of sustained TFR. Early molecular response dynamics were included as a predictive variable, assessed by calculating the patient-specific halving time of BCR-ABL1 after commencing tyrosine kinase inhibitor (TKI) therapy. Overall, 115 patients attempted TFR and had ≥12 months of follow-up. The probability of sustained TFR, defined as remaining in major molecular response off TKI therapy for 12 months, was 55%. The time taken for the BCR-ABL1 value to halve was the strongest independent predictor of sustained TFR: 80% in patients with a halving time of <9.35 days (first quartile) compared with only 4% if the halving time was >21.85 days (last quartile) (P < .001). The e14a2 BCR-ABL1 transcript type and duration of TKI exposure before attempting TFR were also independent predictors of sustained TFR. However, the BCR-ABL1 value measured at 3 months of TKI was not an independent predictor of sustained TFR. A more rapid initial BCR-ABL1 decline after commencing TKI also correlated with an increased likelihood of achieving TFR eligibility. The association between sustained TFR and the time taken for BCR-ABL1 to halve after commencing TKI was validated using an independent dataset. These data support the critical importance of the initial kinetics of BCR-ABL1 decline for long-term outcomes.

Accelerated Phase Chronic Myeloid Leukemia and Treatment Free Remission Maintained After Five Years of Nilotinib: A Case Report

The present article reports the case of a patient presenting with chronic myeloid leukemia, diagnosed during the accelerated phase (>20% blasts in peripheral blood samples and megakaryocyte agglomerates in the bone marrow). The subject was treated with first-line therapy with the tyrosine kinase inhibitor nilotinib and reached complete clinical and molecular remission (according to the European Leukemia Net-ELN-criteria), which persisted over five years of treatment. Five years after discontinuation of nilotinib (ten years from diagnosis), the patient is in good clinical condition, with no traces of BCL-ABL1 at molecular evaluation (molecular response, MR⁵). The case is discussed in the setting of current literature, providing an overview on chronic myeloid leukemia and a discussion on treatment options available.

Relevance of treatment-free remission recommendations in chronic phase chronic leukemia patients treated with frontline tyrosine kinase inhibitors

BACKGROUND

Tyrosine kinase inhibitors (TKI) can be safely discontinued in chronic phase chronic myeloid leukemia (CP-CML) patients who had achieved a sustained deep molecular response. Based on the results of discontinuation trials, recommendations regarding patient selection for a treatment-free remission (TFR) attempt had been proposed. The aims of this study were to evaluate the rate of patients eligible for TKI discontinuation and molecular recurrence-free survival (MRFS) after stop according to recommendations.

METHODS

Over a 10-year period, newly diagnosed CP-CML patients and treated with first-line TKI in the nine French participating centers were included. Eligibility to treatment discontinuation and MRFS were analyzed and compared according to selection criteria defined by recommendations and first-line treatments.

RESULTS

From January 2006 to December 2015, 398 patients were considered. Among them, 73% and 27% of patients received imatinib or either second or third generation tyrosine kinase inhibitors as frontline treatment, respectively. Considering the selection criteria defined by recommendations, up to 55% of the patients were selected as optimal candidates for treatment discontinuation. Overall 95/398 (24%) discontinued treatment. MRFS was 51.8% [95% CI 41.41-62.19] at 2 years and 43.8% [31.45-56.15] at 5 years. Patients receiving frontline second-generation TKI and fulfilling the eligibility criteria suggested by recommendations had the lowest probability of molecular relapse after TKI stop when compare to others.

CONCLUSION

One third of CP-CML patients treated with TKI frontline fulfilled the selection criteria suggested by European LeukemiaNet TFR recommendations. Meeting selection criteria and second-generation TKI frontline were associated with the highest MRFS.

Budget Impact of Tyrosine Kinase Inhibitor Discontinuation in Chronic Myeloid Leukemia With Sustained Deep Molecular Response

OBJECTIVES

Tyrosine kinase inhibitors (TKIs) account for the vast majority of healthcare expenditure on patients with chronic myeloid leukemia (CML), and it has been demonstrated that TKI discontinuation in patients in long-term deep molecular remission (DMR) is safe and improves quality of life. Our objective was to estimate the budget impact of TKI discontinuation in CML patients in long-term DMR from the perspective of the French healthcare system.

METHODS

This analysis was conducted over a 5-year time horizon using a Markov model with cycles of 6 months. Transition probabilities were estimated through systematic reviews and meta-analyses. Costs were estimated from the French National Claims Database. Monte Carlo simulations were performed to take into account the uncertainty surrounding model parameters. Sensitivity analyses were carried out by varying the size of the target population and the cost of TKIs.

RESULTS

Over a 5-year period and for a target population of 100 patients each year eligible and agreeing to stop TKI, the TKI discontinuation strategy would save €25.5 million (95% confidence interval -39.3 to 70.0). In this model, the probability that TKI discontinuation would be more expensive than TKI continuation was 12.0%. In sensitivity analyses, mean savings ranged from €14.9 million to €62.9 million.

CONCLUSIONS

This study provides transparent, reproducible, and interpretable results for healthcare professionals and policy makers. Our results clearly show that innovative healthcare strategies can benefit both the healthcare system and patients. Savings from generalizing TKI discontinuation in CML patients in sustained DMR should yield health gains for other patients.

Health state utility and quality of life measures in patients with chronic myeloid leukemia in France

PURPOSE

Tyrosine kinase inhibitors (TKIs) have dramatically improved the prognosis of chronic myeloid leukemia (CML). We aimed to assess health state utility and quality of life (QoL) in French patients with CML in real-life setting, to study the determinants of utility score and to compare health-related QoL values to general population norms.

METHODS

We conducted a cross-sectional study in 412 patients with CML. Data were collected by electronic survey. Three patient-reported outcomes questionnaires were used: EORTC QLQ-C30, EORTC QLQ-CML24 and EuroQol EQ-5D-3L. Health state utility values were computed using the French value set. We computed deviations from reference norms from the general population. We studied the determinants of health utility score using multiple regression models.

RESULTS

The mean utility score (SD) was 0.72 (0.25) in the chronic phase and 0.84 (0.21) in treatment-free remission, with marked variations by gender. Patients with CML had a deviation from the reference norm of -0.15 on average (SD: 0.25). In terms of QoL, social functioning, role functioning and cognitive functioning were notably impacted with a mean difference of -16.0, -13.1 and -11.7 respectively. Fatigue, dyspnea and pain were the symptoms with the highest deviation from general population norms (mean difference of 20.6, 14.0 and 8.3 respectively). In the multiple regression analysis, fatigue was the most important independent predictor of the utility score.

CONCLUSION

Although TKIs prevent the disease from progressing and even allow remission without treatment, QoL in patients with CML is notably altered. The utility scores deteriorate with CML symptoms.

Prognostic effect of comorbidities in patients with chronic myeloid leukemia treated with a tyrosine kinase inhibitor

Comorbidities at diagnosis among patients with chronic myeloid leukemia in chronic phase (CML-CP) may affect their overall survival (OS) rate even in the tyrosine kinase inhibitor (TKI) era. However, the prognostic impact of comorbidities in patients with CML-CP treated with a second-generation TKI (2GTKI) has not been elucidated. We evaluated the effect of comorbidities on survival using the Charlson Comorbidity Index (CCI) in patients with CML-CP treated with imatinib or a 2GTKI (nilotinib and dasatinib). From April 2010 to March 2013, 506 patients with CML-CP were registered for the population-based cohort study, and 452 with a median age of 56 y were assessable. Treatment groups included 139 patients receiving imatinib, 169 receiving nilotinib, and 144 receiving dasatinib. Comorbidities were diagnosed in 99 patients. CCI scores were stratified as follows: 2, 353 patients; 3, 72 patients; and ≥4, 27 patients. Treatment response did not vary relative to CCI scores. However, across the entire cohort, the OS rate was significantly lower among patients with higher CCI scores than in those with a CCI score of 2 (94.4% in score 2, 89.0% in score 3, and 72.8% in score ≥4; P < .001). Multivariate analysis identified a CCI score of ≥4 as a strong adverse prognostic factor for OS rather than the disease-specific risk factor, older age, performance status, or selection of TKI (Wald test, P < .01). Our results demonstrated that comorbidities at diagnosis were the most important predictive factor for successful treatment, regardless of the TKI type used in CML-CP. This trial was registered at UMIN-CTR as 00003581.

Real-world tyrosine kinase inhibitor treatment pathways, monitoring patterns and responses in patients with chronic myeloid leukaemia in the United Kingdom: the UK TARGET CML study

Management of chronic myeloid leukaemia (CML) has recently undergone dramatic changes, prompting the European LeukemiaNet (ELN) to issue recommendations in 2013; however, it remains unclear whether real-world CML management is consistent with these goals. We report results of UK TARGET CML, a retrospective observational study of 257 patients with chronic-phase CML who had been prescribed a first-line TKI between 2013 and 2017, most of whom received first-line imatinib (n = 203). Although 44% of patients required ≥1 change of TKI, these real-world data revealed that molecular assessments were frequently missed, 23% of patients with ELN-defined treatment failure did not switch TKI, and kinase domain mutation analysis was performed in only 49% of patients who switched TKI for resistance. Major molecular response (MMR; BCR-ABL1IS ≤0·1%) and deep molecular response (DMR; BCR-ABL1IS ≤0·01%) were observed in 50% and 29%, respectively, of patients treated with first-line imatinib, and 63% and 54%, respectively, receiving a second-generation TKI first line. MMR and DMR were also observed in 77% and 44% of evaluable patients with ≥13 months follow-up, receiving a second-generation TKI second line. We found little evidence that cardiovascular risk factors were considered during TKI management. These findings highlight key areas for improvement in providing optimal care to patients with CML.

Handling challenging questions in the management of chronic myeloid leukemia: when is it safe to stop tyrosine kinase inhibitors?

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.

Why is it critical to achieve a deep molecular response in chronic myeloid leukemia?

The primary goal of tyrosine kinase inhibitor (TKI) therapy for patients with chronic myeloid leukemia is survival, which is achieved by the vast majority of patients. The initial response to therapy provides a sensitive measure of future clinical outcome. Measurement of BCR-ABL1 transcript levels using real-time quantitative polymerase chain reaction standardized to the international reporting scale is now the principal recommended monitoring strategy. The method is used to assess early milestone responses and provides a guide for therapeutic intervention. When patients successfully traverse the critical first 12 months of TKI therapy, most will head towards another milestone response, deep molecular response (DMR, BCR-ABL1 ≤0.01%). DMR is essential for patients aiming to achieve treatment-free remission and a prerequisite for a trial of TKI discontinuation. The success of discontinuation trials has led to new treatment strategies in order for more patients to reach this milestone response. DMR has been incorporated into endpoints of clinical trials and is considered by some expert groups as the optimal treatment response. But is DMR a stable response and does it provide the ultimate protection against TKI resistance and death? Do we need to increase the sensitivity of detection of BCR-ABL1 to better identify the patients who would likely remain in treatment-free remission after TKI discontinuation? Is it necessary to switch current TKI therapy to a more potent inhibitor if the goal is to achieve DMR? These are issues that I will explore in this review.

Handling challenging questions in the management of chronic myeloid leukemia: when is it safe to stop tyrosine kinase inhibitors?

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.

Treatment free remission in chronic myeloid leukemia: Lights and shadows

In addition to the best possible overall survival, discontinuation of the tyrosine kinase-inhibitor (TKI) treatment [treatment free remission (TFR)] without observing a recurrence of the disease has become a standard part of chronic myeloid leukemia (CML) care. Worldwide, more than 2000 patients with CML have attempted TFR, and very rare instances of disease transformation have been reported. Several studies in the last decade have demonstrated the feasibility and safety of TKI discontinuation in selected patients with CML who achieve deep and sustained molecular response with TKI. This has moved prime-time into clinical practice although open questions remain in terms of understanding the disease biology that leads to successful TKI cessation in some patients while not in others. Despite the remaining questions regarding which factors may be considered predictive for TFR, treatment interruption is a safe option provided that adequate molecular monitoring is available, with prompt re-initiation of TKIs as soon as major molecular response has been lost. Data from ongoing trials should help refine decisions as to which patients are the best candidates to attempt TKI discontinuation, frequency of a safe monitoring, optimal strategies to sustain ongoing TFR and increase the number of patients who can access to discontinuation programs.

Managing chronic myeloid leukemia for treatment-free remission: a proposal from the GIMEMA CML WP

Several papers authored by international experts have proposed recommendations on the management of BCR-ABL1+ chronic myeloid leukemia (CML). Following these recommendations, survival of CML patients has become very close to normal. The next, ambitious, step is to bring as many patients as possible into a condition of treatment-free remission (TFR). The Gruppo Italiano Malattie EMatologiche dell'Adulto (GIMEMA; Italian Group for Hematologic Diseases of the Adult) CML Working Party (WP) has developed a project aimed at selecting the treatment policies that may increase the probability of TFR, taking into account 4 variables: the need for TFR, the tyrosine kinase inhibitors (TKIs), the characteristics of leukemia, and the patient. A Delphi-like method was used to reach a consensus among the representatives of 50 centers of the CML WP. A consensus was reached on the assessment of disease risk (EUTOS Long Term Survival [ELTS] score), on the definition of the most appropriate age boundaries for the choice of first-line treatment, on the choice of the TKI for first-line treatment, and on the definition of the responses that do not require a change of the TKI (BCR-ABL1 ≤10% at 3 months, ≤1% at 6 months, ≤0.1% at 12 months, ≤0.01% at 24 months), and of the responses that require a change of the TKI, when the goal is TFR (BCR-ABL1 >10% at 3 and 6 months, >1% at 12 months, and >0.1% at 24 months). These suggestions may help optimize the treatment strategy for TFR.

Incidences of Deep Molecular Responses and Treatment-Free Remission in de Novo CP-CML Patients

Simple Summary

Tyrosine kinase inhibitors (TKI) can be safely discontinued in chronic myeloid leukemia patients. Achieving a sustained deep molecular response (DMR) before stop is recommended. Currently, the proportion of patients who achieve a sustained DMR remains to be determined. Based on the follow-up of 398 patients over a ten-years period, we evaluate that 46% of them have achieved a sustained DMR. Gender, BCR-ABL1 transcript type, and disease risk scores were significantly associated with the probability of achieving a DMR. 95/398 (24%) patients stopped TKI with a probability of maintaining molecular reponse without TKI resumption of 47% at 48 months after stop. In this study, TKI duration before stop and second (nilotinib, dasatinib, bosutinib) generation frontline TKI compared to imatinib were significantly associated with a lower risk of molecular relapse after stop in patients who have achieved a sustained DMR.

Abstract

Background: Tyrosine Kinase Inhibitors (TKIs) discontinuation in patients who had achieved a deep molecular response (DMR) offer now the opportunity of prolonged treatment-free remission (TFR). Patients and Methods: Aims of this study were to evaluate the proportion of de novo chronic-phase chronic myeloid leukemia (CP-CML) patients who achieved a sustained DMR and to identify predictive factors of DMR and molecular recurrence-free survival (MRFS) after TKI discontinuation. Results: Over a period of 10 years, 398 CP-CML patients treated with first-line TKIs were included. Median age at diagnosis was 61 years, 291 (73%) and 107 (27%) patients were treated with frontline imatinib (IMA) or second- or third-generation TKIs (2–3G TKI), respectively. With a median follow-up of seven years (range, 0.6 to 13.8 years), 182 (46%) patients achieved a sustained DMR at least 24 months. Gender, BCR-ABL1 transcript type, and Sokal and ELTS risk scores were significantly associated with a higher probability of sustained DMR while TKI first-line (IMA vs. 2–3G TKI) was not. We estimate that 28% of CML-CP would have been an optimal candidate for TKI discontinuation according to recent recommendations. Finally, 95 (24%) patients have entered in a TFR program. MRFS rates at 12 and 48 months were 55.1% (95% CI, 44.3% to 65.9%) and 46.9% (95% CI, 34.9% to 58.9%), respectively. In multivariate analyses, first-line 2–3G TKIs compared to IMA and TKI duration were the most significant factors of MRFS. Conclusions: Our results suggest that frontline TKIs have a significant impact on TFR in patients who fulfill the selection criteria for TKI discontinuation.

Treatment-free remission in chronic myeloid leukemia: the patient perspective and areas of unmet needs

In CML, treatment-free remission (TFR) refers to having a stable deep molecular response without the need for ongoing tyrosine kinase inhibitor treatment. Whilst recommendations exist about the technical management of stopping and re-starting therapy, much is still unknown about the experiences of those considering and undertaking TFR. This study sought to obtain the patient perspective, identify areas of unmet needs and create recommendations for improvements. Fifty-six percent of patients reported fear or anxiety during treatment discontinuation, whereas only 7% of patients were asked if they needed psychological support during this period. Where patients re-initiated treatment; 59% felt scared or anxious, and 56% felt depressed. Twenty-six percent of re-initiated patients received psychological and/or emotional support at this time. Sixty percent of patients experienced withdrawal symptoms whilst discontinuing treatment, however, 40% of patients who experienced withdrawal symptoms reported that they were not fully supported by their doctor in managing all the symptoms. Healthcare professionals should further consider how they monitor the psychological well-being of patients who are discontinuing or re-initiating treatment, and review what support is offered in response to identified concerns. Surveillance of withdrawal symptoms should be a priority during treatment discontinuation, along with how healthcare professionals assist in the management of these.

Prospects for achieving treatment-free remission in chronic myeloid leukaemia

In addition to the best possible overall survival, discontinuation of the tyrosine kinase-inhibitor (TKI) treatment [treatment free remission (TFR)] without observing a recurrence of the disease has become a major goal of the therapy of chronic myelogenous leukemia (CML). Many clinical studies have demonstrated that TFR is possible, although for the moment limited to a fraction of the CML patients able to achieve a stable deep molecular response (DMR). The factors associated to the possibility of remaining in TFR or of losing it, have been investigated by a number of controlled and observation clinical trials and although total TKI treatment duration, DMR duration and stability and, more recently, also the depth of the molecular response obtained at the time of discontinuation have been shown to be significant elements, most of the factors associated with a higher possibility of a successful discontinuation still remain elusive and are here reviewed.

Chronic Myeloid Leukemia Prognosis and Therapy: Criticisms and Perspectives

Ph+ chronic myeloid leukemia (CML) is a clonal myeloproliferative disease whose clinical course is characterized by progression disease from the early chronic phase (CP) to the fatal blastic phase (BP). This programmed course is closely related to the translocation t(9;22)(q22;q11) and the resulting BCR-ABL1 fusion protein (p210) that drives the leukemic transformation of hematopoietic stem cells. Therefore, the cure of CML can only pass through the abrogation of the Ph+ clone. Allogeneic stem cell transplantation (allo-SCT) and interferon-alpha (IFNα) have been proven to reduce the Ph+ clone in a limited proportion of CML population and this translated in a lower rate of progression to BP and in a significant prolongation of survival. Tyrosine-kinase inhibitors (TKIs), lastly introduced in 2000, by preventing the disease blastic transformation and significantly prolonging the survival in up to 90% of the patient population, radically changed the fate of CML. The current therapy with TKIs induces a chronicization of the disease but several criticisms still persist, and the most relevant one is the sustainability of long-term therapy with TKIs in terms of compliance, toxicity and costs. The perspectives concern the optimization of therapy according to the age, the risk of disease, the potency and the safety profiles of the TKIs. The prolongation of survival is the most important end point which should be guaranteed to all patients. The treatment free remission (TFR) is the new goal that we would like to give to an increasing number of patients. The cure remains the main objective of CML therapy.

Low-dose tyrosine kinase inhibitors before treatment discontinuation do not impair treatment-free remission in chronic myeloid leukemia patients: Results of a retrospective study

BACKGROUND

Long-term treatment-free remission (TFR) represents a new goal for chronic myeloid leukemia (CML). In clinical practice, tyrosine kinase inhibitor (TKI) dose reductions can be considered a means of preventing adverse effects and improving quality of life. We hypothesized that administration of low-dose TKIs before treatment discontinuation does not impair TFR in patients with CML who have a deep molecular response (DMR, ≥MR⁴ ).

METHODS

We conducted a retrospective analysis of 77 patients with CML who discontinued treatment with TKIs. Twenty-six patients had been managed with low-dose TKIs before stopping treatment. Patients were to be exposed to TKIs for ≥5 years and to low-dose TKIs for ≥1 year and in DMR for ≥2 years. The loss of major molecular response (MMR) was considered a trigger for restarting therapy.

RESULTS

In the low-dose group, 61.5% of patients received second-generation TKIs, and dose reduction was ≥50% for 65.4% of patients. With a median follow-up of 61.5 months, TFR at 12 months was 56.8% in the full-dose TKI group and 80.8% in the low-dose group, and TFR at 60 months was 47.5% and 58.8%, respectively. The median time to molecular recurrence (≥MMR) from TKI discontinuation in the entire cohort was 6.2 months. All patients quickly achieved MMR after resuming TKI therapy. Results appear independent of both dose reduction and potential pretreatment with interferon-α.

CONCLUSION

This retrospective study shows that TFR was not impaired by low-dose TKI regimens before TKI cessation in Patients with CML. Nevertheless, prospective randomized clinical trials must be undertaken to analyze the probability of successful TFR in patients managed with TKI dose de-escalation strategies before TKI discontinuation.

Risk of molecular recurrence after tyrosine kinase inhibitor discontinuation in chronic myeloid leukaemia patients: a systematic review of literature with a meta-analysis of studies over the last ten years

More than 10 years ago, the first pilot observational study of imatinib discontinuation was reported in chronic myeloid leukaemia (CML) patients in deep molecular response (DMR). Several studies have been published since then, in patients treated with frontline imatinib, or second-generation tyrosine kinase inhibitors (TKI) in first or second line but also on second attempt of TKI discontinuation. Our objective was to estimate, through meta-analyses of the literature data, the probability of molecular recurrence (MolRec) in the time periods of 0-6, 6-12, 12-18 and 18-24 months after a first and second TKI discontinuation and the probability of re-acquisition of DMR after MolRec. The Medline and Scopus databases were searched up to April 2019. The studies were selected by three independent reviewers. Random-effect meta-analyses were conducted using the MetaXL software. The probability of MolRec in the time periods 0-6, 6-12, 12-18 and 18-24 months after the first attempt was respectively 35%, 8%, 3% and 3%, whereas the probability of MolRec in the time periods 0-6, 6-12 and 12-18 after the second attempt was 48%, 27% and 12% respectively. Re-acquisition of a DMR was observed in 90% of patients. Most of the MolRec occur during the first six months in case of a first attempt, whereas the second MolRec occurs over a larger window of time.

What are the considerations for tyrosine kinase inhibitor discontinuation in chronic-phase chronic myeloid leukemia?

Introduction: The outlook for patients with chronic myeloid leukemia (CML) has changed dramatically with the development of tyrosine kinase inhibitors (TKIs) with the current treatment goal for many patients being to obtain a durable deep molecular remission, discontinue TKI therapy, and remain treatment free.Areas covered: In this article, the authors review the data from the major TKI discontinuation studies, explore potential predictors of discontinuation outcome and look at possible mechanisms to explain the variable outcomes following TKI discontinuation including immune surveillance and leukemic stem cell (LSC) depletion following TKI treatment. Data from relevant articles published on the Pubmed database between January 2007 and January 2020 have been included.Expert opinion: The results from the majority of TKI discontinuation studies show a consistent picture with approximately half of eligible patients achieving treatment free remission (TFR). However, reliable clinical predictors or biomarkers for the outcome of TKI discontinuation remain elusive and the mechanisms to explain the diversity of discontinuation success are not completely understood. Future studies will need to focus on attempts to increase the number of patients eligible for treatment discontinuation and will likely involve drug combinations including novel agents aimed at targeting the residual LSC population and enhancement of immune surveillance mechanisms.

Evaluation and characterisation of Chronic myeloid leukemia and various treatments in Saudi Arabia: A retrospective study

BACKGROUND

Chronic myeloid leukemia (CML) is a clonal BCR-ABL1-positive myelo-proliferative disorder resulting from an acquired genetic mutation, characterized by the presence of the Philadelphia (Ph) chromosome. CML is associated with significantly high granulocyte numbers in the bone marrow and peripheral blood.

MATERIALS AND METHODS

This retrospective study conducted at the Hematology Unit of King Saud University Medical City aimed to evaluate the incidence and characteristics of CML and the various treatments in Saudi Arabia. We have evaluated the demographic, clinical, and hematological data of 56 consecutive patients who visited the hospital from Jan 2012 to Jan 2018.

RESULTS

The diagnosis and stage of CML were determined based on the World Health Organization criteria, following polymerase chain reaction analysis of bone marrow aspirates. Our study group had equal numbers of genders with a age mean of 43.3+18.1 years. The predominance of younger patients and equal incidence in males and females could be due to the racial and socioeconomic disparities among our patients compared to those in previous studies. While the most predominant symptom was fatigue and bone pain, the most common clinical sign was hepato-splenomegaly, followed by remarkable weight loss, and epistaxis.

CONCLUSION

A patient with an increased WBC count, abdominal pain, left side distension, and hepato-splenomegaly should clearly be evaluated for CML.

Pharmacology of tyrosine kinase inhibitors in chronic myeloid leukemia; a clinician's perspective

OBJECTIVE

In this review, we have summarized the pharmacokinetics, pharmacodynamics and adverse effects of imatinib, dasatinib, nilotinib, bosutinib, ponatinib and radotinib with focus on pharmacogenomic studies with clinical end points. We have discussed the key phase 3 trials of tyrosine kinase inhibitors (TKI) comparing with each other, treatment free remission (TFR) and selection of TKI. Upcoming concepts and related trials in the management of chronic myeloid leukemia (CML) along with future directions have been touched upon.

EVIDENCE ACQUISITION

PubMed, Embase, Google, Cochrane library and Medline were searched to identify relevant literature for the review. Clinicaltrial.gov was searched for upcoming data and trials.

RESULTS

There are lot of gap in pharmacokinetics and pharmacodynamics of TKI. Imatinib appears to be the safest TKI. Newer TKI's achieve better achievement of therapeutic milestones, deeper molecular response and less chances of progression of CML compared to imatinib. Newer TKI appears to be better choice for achieving TFR. When the objective is survival, imatinib is still the TKI of choice. Primary prophylaxis with antiplatelet drugs for TKI having cardiovascular and thromboembolic side effects should be considered.

CONCLUSION

Pharmacogenetic data of TKI is still immature to guide in therapeutic decision making in clinical practice. There is need for further research in pharmacology and pharmacogenomics of newer TKI's. Randomized controlled trials are required to decide the optimum TKI for TFR. Safe and effective TKI for targeting T315I mutation, CML accelerated phase and blast crisis are an active area of research.

Towards a Personalized Treatment of Patients with Chronic Myeloid Leukemia

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.

Lineage of measurable residual disease in patients with chronic myeloid leukemia in treatment-free remission

Approximately half of patients with chronic myeloid leukemia (CML) in sustained deep molecular response who discontinue tyrosine kinase inhibitors (TKIs) remain in treatment-free remission (TFR). Some of these patients have measurable residual disease (MRD) by BCR-ABL1 mRNA testing, and most have detectable BCR-ABL1 DNA by highly sensitive methods. We used fluorescence-activated cell sorting and BCR-ABL1 DNA PCR to investigate the lineage of residual CML cells in TFR. Twenty patients in TFR for >1 year provided blood for sorting into granulocytes, monocytes, B cells, T cells, and NK cells. MRD was identified predominantly in the lymphoid compartment and never in granulocytes. B cells were more often BCR-ABL1 positive than T cells (18 vs 11/20 patients) and at higher levels (median 10^-4.9 vs 10^-5.7; P = 0.014). In 13 CML patients studied at diagnosis lymphocytes expressing BCR-ABL1 mRNA comprised a small proportion of total leukocytes. These data improve our understanding of TFR biology, since it is now clear that MRD in the blood of TFR patients need not imply the persistence of multipotent CML cells. Lineage-specific assessment of MRD could be explored as a means to improve the prediction of TFR.

T315I-mutated myeloid sarcoma

Myeloid Sarcoma (MS) is diagnosed by an extramedullary proliferation of immature granulocytic cells. Its association with chronic myeloid leukemia (CML) is rare. CML is characterized by BCR-ABL1 gene rearrangement and therapies with tyrosine kinase inhibitors (TKI) are very effective. However, TKI resistance may occur secondary to the development of ABL1 mutations. T315I is a common mutation that accounts for ∼20% clinical resistance to TKIs. We report the first case of a patient with T315I mutated myeloid sarcoma that occurred after complete cytogenetic response with dasatinib of a chronic phase CML. The patient was successfully treated with induction chemotherapy and ponatinib.

[Recommendations from the French CML Study Group (Fi-LMC) for BCR-ABL1 kinase domain mutation analysis in chronic myeloid leukemia]

In the context of chronic myeloid leukemia (CML) resistant to tyrosine kinase inhibitors (TKIs), BCR-ABL1 tyrosine kinase domain (TKD) mutations still remain the sole biological marker that directly condition therapeutic decision. These recommendations aim at updating the use of BCR-ABL1 mutation testing with respect to new available therapeutic options and at repositioning different testing methods at the era of next generation sequencing (NGS). They have been written by a panel of experts from the French Study Group on CML (Fi-LMC), after a critical review of relevant publications. TKD mutation testing is recommended in case of treatment failure but not in case of optimal response. For patients in warning situation, mutation testing must be discussed depending on the type of TKI used, lasting of the treatment, kinetic evolution of BCR-ABL1 transcripts along time and necessity for switching treatment. The kind and the frequency of TKD mutations occasioning resistance mainly depend on the TKI in use and disease phase. Because of its better sensitivity, NGS methods are recommended for mutation testing rather than Sanger's. Facing a given TKD mutation, therapeutic decision should be taken based on in vitro sensitivity and clinical efficacy data. Identification by sequencing of a TKD mutation known to induce resistance must lead to a therapeutic change. The clinical value of testing methods more sensitive than NGS remains to be assessed.