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

Health-related quality of life and symptoms of chronic myeloid leukemia patients after discontinuation of tyrosine kinase inhibitors: results from the EURO-SKI Trial

Limited data is available on the health-related quality of life (HRQoL) and symptoms of patients with chronic myeloid leukemia (CML) who are in treatment-free remission (TFR). We herein report HRQoL results from the EURO-SKI trial. Patients who had been on tyrosine kinase inhibitors (TKIs) therapy for at least 3 years and achieved MR4 for at least 1 year were enrolled from 11 European countries, and the EORTC QLQ-C30 and the FACIT-Fatigue questionnaires were used to assess HRQoL and fatigue respectively. Patients were categorized into the following age groups: 18-39, 40-59, 60-69 and ≥70 years. Of 728 patients evaluated at baseline, 686 (94%) completed HRQoL assessments. The median age at TKI discontinuation was 60 years. Our findings indicate that HRQoL and symptom trajectories may vary depending on specific age groups, with younger patients benefiting the most. Improvements in patients aged 60 years or older were marginal across several HRQoL and symptom domains. At the time of considering TKI discontinuation, physicians could inform younger patients that they may expect valuable HRQoL benefits. Considering the marginal improvements observed in patients aged 60 years or above, it may be important to further investigate the value of TFR compared to a lowest effective dose approach in this older group of patients.

Chronic myeloid leukaemia: Biology and therapy

Chronic myeloid leukaemia (CML) is caused by BCR::ABL1. Tyrosine kinase-inhibitors (TKIs) are the initial therapy. Several organizations have reported milestones to evaluate response to initial TKI-therapy and suggest when a change of TKI should be considered. Achieving treatment-free remission (TFR) is increasingly recognized as the optimal therapy goal. Which TKI is the best initial therapy for which persons and what depth and duration of molecular remission is needed to achieve TFR are controversial. In this review we discuss these issues and suggest future research directions.

Oral arsenic plus imatinib versus imatinib solely for newly diagnosed chronic myeloid leukemia: a randomized phase 3 trial with 5-year outcomes

PURPOSE

The synergistic effects of combining arsenic compounds with imatinib against chronic myeloid leukemia (CML) have been established using in vitro data. We conducted a clinical trial to compare the efficacy of the arsenic realgar-indigo naturalis formula (RIF) plus imatinib with that of imatinib monotherapy in patients with newly diagnosed chronic phase CML (CP-CML).

METHODS

In this multicenter, randomized, double-blind, phase 3 trial, 191 outpatients with newly diagnosed CP-CML were randomly assigned to receive oral RIF plus imatinib (n = 96) or placebo plus imatinib (n = 95). The primary end point was the major molecular response (MMR) at 6 months. Secondary end points include molecular response 4 (MR4), molecular response 4.5 (MR4.5), progression-free survival (PFS), overall survival (OS), and adverse events.

RESULTS

The median follow-up duration was 51 months. Due to the COVID-19 pandemic, the recruitment to this study had to be terminated early, on May 28, 2020. The rates of MMR had no significant statistical difference between combination and imatinib arms at 6 months and any other time during the trial. MR4 rates were similar in both arms. However, the 12-month cumulative rates of MR4.5 in the combination and imatinib arms were 20.8% and 10.5%, respectively (p = 0.043). In core treatment since the 2-year analysis, the frequency of MR4.5 was 55.6% in the combination arm and 38.6% in the imatinib arm (p = 0.063). PFS and OS were similar at five years. The safety profiles were similar and serious adverse events were uncommon in both groups.

CONCLUSION

The results of imatinib plus RIF as a first-line treatment of CP-CML compared with imatinib might be more effective for achieving a deeper molecular response (Chinadrugtrials number, CTR20170221).

ESMO-Magnitude of Clinical Benefit Scale for haematological malignancies (ESMO-MCBS:H) version 1.0

BACKGROUND

The European Society for Medical Oncology (ESMO)-Magnitude of Clinical Benefit Scale (MCBS) has been accepted as a robust tool to evaluate the magnitude of clinical benefit reported in trials for oncological therapies. However, the ESMO-MCBS hitherto has only been validated for solid tumours. With the rapid development of novel therapies for haematological malignancies, we aimed to develop an ESMO-MCBS version that is specifically designed and validated for haematological malignancies.

METHODS

ESMO and the European Hematology Association (EHA) initiated a collaboration to develop a version for haematological malignancies (ESMO-MCBS:H). The process incorporated five landmarks: field testing of the ESMO-MCBS version 1.1 (v1.1) to identify shortcomings specific to haematological diseases, drafting of the ESMO-MCBS:H forms, peer review and revision of the draft based on re-scoring (resulting in a second draft), assessment of reasonableness of the scores generated, final review and approval by ESMO and EHA including executive boards.

RESULTS

Based on the field testing results of 80 haematological trials and extensive review for feasibility and reasonableness, five amendments to ESMO-MCBS were incorporated in the ESMO-MCBS:H addressing the identified shortcomings. These concerned mainly clinical trial endpoints that differ in haematology versus solid oncology and the very indolent nature of nevertheless incurable diseases such as follicular lymphoma, which hampers presentation of mature data. In addition, general changes incorporated in the draft version of the ESMO-MCBS v2 were included, and specific forms for haematological malignancies generated. Here we present the final approved forms of the ESMO-MCBS:H, including instructions.

CONCLUSION

The haematology-specific version ESMO-MCBS:H allows now full applicability of the scale for evaluating the magnitude of clinical benefit derived from clinical studies in haematological malignancies.

A Multicenter Retrospective Chart Review Study of Treatment and Disease Patterns and Clinical Outcomes of Patients with Chronic-Phase Chronic Myeloid Leukemia in Third-Line Treatment or with T315I Mutation

This retrospective chart review study investigated the clinical burden of adult patients with chronic-phase chronic myeloid leukemia (CP-CML) treated at three centers in France (2006-2021) who failed on two or more tyrosine kinase inhibitors (TKIs; third-line [3L]+ cohort) or harbored the BCR::ABL1 T315I mutation (T315I cohort). In the 3L+ cohort (N = 157; median age at diagnosis, 56 years), TKIs received in 3L (median duration: 17 months) were dasatinib (32%), nilotinib (19%), imatinib (18%), ponatinib (17%), and bosutinib (14%). Of the 145 patients with documented responses in 3L, 42% experienced major molecular response (MMR) at 12 months. Median event-free survival [95% confidence interval] was 53.6 [44.0, 67.5] months, and median progression-free survival and overall survival (OS) were not reached. Achieving MMR in 3L was associated with a decreased mortality risk. In the T315I cohort (N = 17; 52 years), 41% of patients received five or more lines of therapy. Following identification of the T315I mutation, ponatinib was the most common TKI used (59%); the median [interquartile range] OS was 5 [3-10] years. The most common adverse events were infections (3L+ cohort) and thrombocytopenia (T315I cohort) (both 18%). Well-tolerated therapies that achieve durable responses are needed in 3L or earlier to improve CP-CML prognosis.

Control of Ph+ and additional chromosomal abnormalities in chronic myeloid leukemia by tyrosine kinase inhibitors

Chronic myeloid leukemia (CML) is a type of blood cancer that is known to affect hematopoietic stem cells. The presence of the Philadelphia chromosome (Ph+) is the major characteristic of CML. A protein expressed by the Philadelphia chromosome shows elevated tyrosine kinase activity and is considered a tumorigenic factor. The first line of therapy that had been established for CML was "imatinib," a potent tyrosine kinase inhibitor. Various other second- and third-generation TKIs are taken into account in cases of imatinib failure/resistance. With the subsequent rise in the development of tyrosine kinase inhibitors, optimization in the treatment of CML and amplified total survival were observed throughout TKI dosage. As the disease progresses, additional chromosomal abnormalities (ACAs) have been reported, but their prognostic effect and impact on the response to treatment are still unknown. However, some substantial understandings have been achieved into the disease transformation mechanisms, including the role of somatic mutations, ACAs, and several different genomic mutations that occur during diagnosis or have evolved during treatment. The acquisition of ACAs impedes CML treatment. Due to additional chromosomal lesions, there are greater chances of future disease progression at the time of CML diagnosis beyond the Ph+ translocation. The synchronous appearance of two or more ACAs leads to lower survival and is classified as a poor prognostic group. The key objective of this review is to provide detailed insights into TKIs and their role in controlling Ph+ and ACAs, along with their response, treatment, overall persistence, and survival rate.

Molecular BCR::ABL1 Quantification and ABL1 Mutation Detection as Essential Tools for the Clinical Management of Chronic Myeloid Leukemia Patients: Results from a Brazilian Single-Center Study

Chronic myeloid leukemia (CML) is a well-characterized oncological disease in which virtually all patients possess a translocation (9;22) that generates the tyrosine kinase BCR::ABL1 protein. This translocation represents one of the milestones in molecular oncology in terms of both diagnostic and prognostic evaluations. The molecular detection of the BCR::ABL1 transcription is a required factor for CML diagnosis, and its molecular quantification is essential for assessing treatment options and clinical approaches. In the CML molecular context, point mutations on the ABL1 gene are also a challenge for clinical guidelines because several mutations are responsible for tyrosine kinase inhibitor resistance, indicating that a change may be necessary in the treatment protocol. So far, the European LeukemiaNet and the National Comprehensive Cancer Network (NCCN) have presented international guidelines on CML molecular approaches, especially those related to BCR::ABL1 expression. In this study, we show almost three years' worth of data regarding the clinical treatment of CML patients at the Erasto Gaertner Hospital, Curitiba, Brazil. These data primarily comprise 155 patients and 532 clinical samples. BCR::ABL1 quantification by a duplex-one-step RT-qPCR and ABL1 mutations detection were conducted. Furthermore, digital PCR for both BCR::ABL1 expression and ABL1 mutations were conducted in a sub-cohort. This manuscript describes and discusses the clinical importance and relevance of molecular biology testing in Brazilian CML patients, demonstrating its cost-effectiveness.

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.

Chronic Myeloid Leukemia, from Pathophysiology to Treatment-Free Remission: A Narrative Literature Review

Chronic myeloid leukemia (CML) is one of the most common leukemias occurring in the adult population. The course of CML is divided into three phases: the chronic phase, the acceleration phase, and the blast phase. Pathophysiology of CML revolves around Philadelphia chromosome that constitutively activate tyrosine kinase through BCR-ABL1 oncoprotein. In the era of tyrosine kinase inhibitors (TKIs), CML patients now have a similar life expectancy to people without CML, and it is now very rare for CML patients to progress to the blast phase. Only a small proportion of CML patients have resistance to TKI, caused by BCR-ABL1 point mutations. CML patients with TKI resistance should be treated with second or third generation TKI, depending on the BCR-ABL1 mutation. Recently, many studies have shown that it is possible for CML patients who achieve a long-term deep molecular response to stop TKIs treatment and maintain remission. This review aimed to provide an overview of CML, including its pathophysiology, clinical manifestations, the role of stem cells, CML treatments, and treatment-free remission.

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.

Bosutinib versus imatinib for newly diagnosed chronic phase chronic myeloid leukemia: final results from the BFORE trial

This analysis from the multicenter, open-label, phase 3 BFORE trial reports efficacy and safety of bosutinib in patients with newly diagnosed chronic phase (CP) chronic myeloid leukemia (CML) after five years’ follow-up. Patients were randomized to 400-mg once-daily bosutinib (n = 268) or imatinib (n = 268; three untreated). At study completion, 59.7% of bosutinib- and 58.1% of imatinib-treated patients remained on study treatment. Median duration of treatment and time on study was 55 months in both groups. Cumulative major molecular response (MMR) rate by 5 years was higher with bosutinib versus imatinib (73.9% vs. 64.6%; odds ratio, 1.57 [95% CI, 1.08–2.28]), as were cumulative MR⁴ (58.2% vs. 48.1%; 1.50 [1.07–2.12]) and MR^4.5 (47.4% vs. 36.6%; 1.57 [1.11–2.22]) rates. Superior MR with bosutinib versus imatinib was consistent across Sokal risk groups, with greatest benefit seen in patients with high risk. Treatment-emergent adverse events (TEAEs) were consistent with 12-month data. After 5 years of follow-up there was an increase in the incidence of cardiac, effusion, renal, and vascular TEAEs in bosutinib- and imatinib-treated patients, but overall, no new safety signals were identified. These final results support 400-mg once-daily bosutinib as standard-of-care in patients with newly diagnosed CP CML.

This trial was registered at www.clinicaltrials.gov as #NCT02130557.

Questions concerning tyrosine kinase-inhibitor therapy and transplants in chronic phase chronic myeloid leukaemia

In this provocative commentary, we consider several questions posed by the late chronic myeloid leukaemia (CML) expert Prof. Michele Baccarani, which he challenged us to address after his death. He noted only a small proportion of people with chronic phase CML receiving tyrosine kinase-inhibitor (TKI)-therapy are likely to achieve sustained therapy-free remission (TFR) and even fewer are likely to be cured. Persons most likely to fail TKItherapy can be identified at diagnosis or soon after starting TKI-therapy. These persons are likely to need lifetime TKI-therapy with attendant risks of adverse events, cost and psychological consequences. Allogeneic transplants achieve much higher rates of leukaemia-free survival compared with TKI-therapy but are associated with transplant-related adverse events including an almost 20 percent risk of transplant-related deaths within 1 year post-transplant and a compromised quality-of-life because of complications such as chronic graft-versus-host disease. Subject-, disease- and transplant-related co-variates associated with transplant outcomes are known with reasonable accuracy. Not everyone likely to fail TKI-therapy is a transplant candidate. However, in those who candidates are physicians and patients need to weigh benefits and risks of TKI-therapy versus a transplant. We suggest transplants should be more often considered in the metric when counseling people with chronic phase CML unlikely to achieve TFR with TKI-therapy. We question whether we are discounting a possible important therapy intervention; we think so.

Chronic myeloid leukemia: cytogenetics and molecular biology’s part in the comprehension and management of the pathology and treatment evolution

Background

Chronic myelogenous leukemia (CML) is a type of blood cancer that affects hematopoietic stem cells and is often characterized by the presence of the Philadelphia chromosome. The Philadelphia chromosome encodes for a protein with high tyrosine kinase activity which acts as a tumorigenic factor.

Main body

This review article reports an update on the pathophysiology of CML and highlights the role of cytogenetic and molecular biology in screening, diagnosis, therapeutic monitoring as well as evaluating patients’ response to treatment. Additionally, these genetic tests allow identifying additional chromosomal abnormalities (ACA) and BCR-ABL tyrosine kinase domain mutations in intolerant or resistant patients. Thus, therapeutic advances have enabled this pathology to become manageable and almost curable in its clinical course. The scientific literature search used in the synthesis of this paper was carried out in the PubMed database, and the figures were generated using online software named BioRender.

Conclusion

The role of cytogenetic and molecular biology is crucial for the diagnosis and medical monitoring of patients. In-depth knowledge of molecular mechanisms of the BCR-ABL kinase facilitated the development of new targeted therapies that have improved the vital prognosis in patients. However, the emergence of ACA and new mutations resistant to tyrosine kinase inhibitors constitutes a real challenge in the quest for adequate therapy.