Long-term safety and efficacy of imatinib mesylate (Gleevec®) in elderly patients with chronic phase chronic myelogenous leukemia: results of the AFR04 study

Mitochondrial Dysfunction in Cardiotoxicity Induced by BCR-ABL1 Tyrosine Kinase Inhibitors -Underlying Mechanisms, Detection, Potential Therapies

The advent of BCR-ABL tyrosine kinase inhibitors (TKIs) targeted therapy revolutionized the treatment of chronic myeloid leukemia (CML) patients. Mitochondria are the key organelles for the maintenance of myocardial tissue homeostasis. However, cardiotoxicity associated with BCR-ABL1 TKIs can directly or indirectly cause mitochondrial damage and dysfunction, playing a pivotal role in cardiomyocytes homeostatic system and putting the cancer survivors at higher risk. In this review, we summarize the cardiotoxicity caused by BCR-ABL1 TKIs and the underlying mechanisms, which contribute dominantly to the damage of mitochondrial structure and dysfunction: endoplasmic reticulum (ER) stress, mitochondrial stress, damage of myocardial cell mitochondrial respiratory chain, increased production of mitochondrial reactive oxygen species (ROS), and other kinases and other potential mechanisms of cardiotoxicity induced by BCR-ABL1 TKIs. Furthermore, detection and management of BCR-ABL1 TKIs will promote our rational use, and cardioprotection strategies based on mitochondria will improve our understanding of the cardiotoxicity from a mitochondrial perspective. Ultimately, we hope shed light on clinical decision-making. By integrate and learn from both research and practice, we will endeavor to minimize the mitochondria-mediated cardiotoxicity and reduce the adverse sequelae associated with BCR-ABL1 TKIs.

Cancer survival statistics for patients and healthcare professionals - a tutorial of real-world data analysis

Monitoring survival of cancer patients using data collected by population-based cancer registries is an important component of cancer control. In this setting, patient survival is often summarized using net survival, that is survival from cancer if there were no other possible causes of death. Although net survival is the gold standard for comparing survival between groups or over time, it is less relevant for understanding the anticipated real-world prognosis of patients. In this review, we explain statistical concepts targeted towards patients, clinicians and healthcare professionals that summarize cancer patient survival under the assumption that other causes of death exist. Specifically, we explain the appropriate use, interpretation and assumptions behind statistical methods for competing risks, loss in life expectancy due to cancer and conditional survival. These concepts are relevant when producing statistics for risk communication between physicians and patients, planning for use of healthcare resources, or other applications when consideration of both cancer outcomes and the competing risks of death is required. To reinforce the concepts, we use Swedish population-based data of patients diagnosed with cancer of the breast, prostate, colon and chronic myeloid leukaemia. We conclude that when choosing between summary measures of survival it is critical to characterize the purpose of the study and to determine the nature of the hypothesis under investigation. The choice of terminology and style of reporting should be carefully adapted to the target audience and may range from summaries for specialist readers of scientific publications to interactive online tools aimed towards lay persons.

Population-based utilization and costs associated with tyrosine kinase inhibitors for first-line treatment of chronic myelogenous leukemia among elderly patients

BACKGROUND: Following approval of imatinib, a breakthrough tyrosine kinase inhibitor (TKI), survival significantly improved by more than 20% since 2001 among treated chronic myelogenous leukemia (CML) patients. Subsequently, more expensive second-generation TKIs with varying selectivity profiles have been approved. Population-based studies are needed to evaluate the real-world utilization of TKI therapies, particularly given their escalating costs and recommendations for maintenance therapy. OBJECTIVE: To assess the utilization patterns of first-line TKIs, overall and by specific agent, among elderly CML patients in the United States, and the cost implications. METHODS: CML patients aged 65 years and older at diagnosis between 2007 and 2015 were identified from population-based cancer registries in the linked Surveillance, Epidemiology, and End Results (SEER)-Medicare database. The percentage of CML patients receiving imatinib, dasatinib, or nilotinib within the first year of diagnosis was calculated along with time to first-line treatment initiation. Bivariate comparisons and Cox proportional hazards models were used to identify factors associated with TKI initiation. Average monthly patient responsibility, including patient out-of-pocket (OOP) costs, stratified by Part D low-income subsidy (LIS) status were also calculated. RESULTS: Among the 1,589 CML patients included, receipt of any TKI within 1 year of diagnosis increased from 66.2% to 78.9%. In 2015, the distribution of first-line TKI therapies was 41.3% imatinib, 28.3% dasatinib, and 9.3% nilotinib. Almost 60% of patients initiated TKI treatment within 3 months of diagnosis. Multivariable analysis indicated that TKI use in the first year was lower among the very elderly (aged > 75 years vs. 65-69 years: HR = 0.72; 95% CI = 0.63-0.83), patients with more comorbidities (Hierarchical Condition Category risk score > 2 vs. HR = 0.74, 95% CI = 0.62-0.88), and patients ineligible for LIS (HR = 0.75; 95% CI = 0.65-0.87). Average monthly patient OOP cost was significantly lower for LIS-eligible versus LIS-ineligible patients: imatinib (2016: $12 vs. $487), dasatinib (2016: $34 vs. $557), and nilotinib (2016: $1 vs. $526). CONCLUSIONS: TKI use has increased significantly since 2007. While imatinib remained the most frequently prescribed first-line agent, by 2015 newer TKIs represented one third of the market share. Utilization patterns indicated persistent age, comorbidity, and financial barriers. TKI use is indicated for long-term therapy, and increased adoption of newer, more expensive agents raises concerns about the sustained affordability of CML treatment, particularly among unsubsidized patients. DISCLOSURES: No outside funding supported this study. There are no reported conflicts of interest.

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.

Differences in treatment and monitoring of chronic myeloid leukemia with regard to age, but not sex: Results from a population-based study

There are established guidelines for treatment and monitoring of chronic myeloid leukemia (CML) but little is known about routine care. Data on ICD-10 codes as well as prescribed medications were available for 10.5 million patients in the statutory health insurance system in Bavaria for the years 2010 to 2016. Also, data on the molecular and cytogenetic monitoring were integrated. A total of 1714 adult patients with CML were observed. Only 50.8% received more than 67.5 daily doses per quarter year (target: 91.5) while 18.2% did not receive any tyrosine kinase inhibitor (TKI). The median number of daily doses was at least 80 doses per quarter year for all age groups in men, but decreased to 62 doses in elderly women. With this exception, no differences between men and women were observed. The percentage of patients without any TKI increased with age. The median number of molecular examinations was 3.54 independent of age and sex. Even in a highly developed country, still a considerable number of patients with CML seem to not receive adequate treatment, whereas molecular monitoring can be considered satisfactory.

Chronic myeloproliferative neoplasms in the elderly

This review focuses on the management of elderly patients with chronic myeloid leukemia and chronic myeloproliferative neoplasms, including polycythemia vera, essential thrombocythemia and primary myelofibrosis. Median age in these neoplasms is within the 6th decades of age. All new therapies can be done at any age without absolute contraindication. However, the selection of the precise therapy for the single patient is mandatory. For these reasons, an accurate definition of diagnosis and prognostication is necessary. Precision in disease definition and prognostication is definitively helpful for personalizing therapeutic approach.

Long-term follow-up of de novo chronic phase chronic myelogenous leukemia patients on front-line imatinib

For the last 15years, imatinib mesylate (IM) has represented the gold standard treatment for chronic-phase chronic myelogenous leukemia (CP-CML); however, outcomes in the very long term remain unknown. We retrospectively analyzed the outcome of 418 IM first-line treated CP-CML patients followed in three reference centers over 15years in and outside of clinical trials, which is believed to represent the "real-life" care of such patients. Molecular analyses were standardized over the years. In case of intolerance or resistance or IM cessation and progression, all clinical data were collected and analyzed. After a median follow-up of 83 months (range 1-194), the overall survival (OS) rates were 91% and 82%, the progression-free survival (PFS) rates were 88.5% and 81%, and the event-free survival rates, including switching to another tyrosine kinase inhibitor, were 65% and 51%, respectively, at 5 and 10years. Thirteen patients (3%) entered blast crisis (BC) with a median survival of 2.2years after BC onset. Forty-nine percent of patients were in major molecular response at 1 year. Univariate analysis failed to detect any impact on survival of molecular response at 3 and 6 months. Sokal score had a significant impact on OS and PFS in a Cox model. Age had a significant impact on OS and PFS, mainly due to deaths in elderly patients unrelated to CML. Overall, 21% of patients reached a stable (≥1 year) molecular response 4 (MR4) and 6.5% reached MR4.5. At last follow-up, 63% of patients were still on IM and 19% were in treatment-free remission. We conclude that IM is an excellent therapeutic option providing impressive long-term OS rates.

Chronic myeloid leukemia in the Netherlands: a population-based study on incidence, treatment, and survival in 3585 patients from 1989 to 2012

OBJECTIVE

To assess the impact and results of treatment of CML in the general population, we conducted a population-based, nationwide study on 3585 CML patients diagnosed between 1989 and 2012 in the Netherlands.

METHODS

Patient demographics were obtained from the Netherlands Cancer Registry. Information on age, gender, year of diagnosis, first treatment, and date of death were recorded. Overall survival (OS) was adjusted for death rates in the normal population.

RESULTS

Incidence in males decreased slightly from 1.2 per 100.000 person years (PY) in 1989-2000 to 0.9 in 2001-2012. For females, incidence remained stable with 0.7 per 100.000 PY in both periods. Incidence was age dependent and highest in males in the last decades of life. Treatment before 2000 mainly consisted of chemotherapy, while after 2007 TKI use was 88%. Five-year relative survival was only 36% before the introduction of TKIs but significantly increased to 79% after the introduction of TKI.

CONCLUSIONS

This study gives insight into CML incidence, treatment, and survival in routine care in the Netherlands. Although OS improved since the introduction of TKIs, there is still room for further improvement.

Ageing is a risk factor in imatinib mesylate cardiotoxicity

AIMS

Chemotherapy-induced heart failure is increasingly recognized as a major clinical challenge. Cardiotoxicity of imatinib mesylate, a highly selective and effective anticancer drug belonging to the new class of tyrosine kinase inhibitors, is being reported in patients, some progressing to congestive heart failure. This represents an unanticipated challenge that could limit effective drug use. Understanding the mechanisms and risk factors of imatinib mesylate cardiotoxicity is crucial for prevention of cardiovascular complications in cancer patients.

METHODS AND RESULTS

We used genetically engineered mice and primary rat neonatal cardiomyocytes to analyse the action of imatinib on the heart. We found that treatment with imatinib (200 mg/kg/day for 5 weeks) leads to mitochondrial-dependent myocyte loss and cardiac dysfunction, as confirmed by electron microscopy, RNA analysis, and echocardiography. Imatinib cardiotoxicity was more severe in older mice, in part due to an age-dependent increase in oxidative stress. Mechanistically, depletion of the transcription factor GATA4 resulting in decreased levels of its prosurvival targets Bcl-2 and Bcl-XL was an underlying cause of imatinib toxicity. Consistent with this, GATA4 haploinsufficient mice were more susceptible to imatinib, and myocyte-specific up-regulation of GATA4 or Bcl-2 protected against drug-induced cardiotoxicity.

CONCLUSION

The results indicate that imatinib action on the heart targets cardiomyocytes and involves mitochondrial impairment and cell death that can be further aggravated by oxidative stress. This in turn offers a possible explanation for the current conflicting data regarding imatinib cardiotoxicity in cancer patients and suggests that cardiac monitoring of older patients receiving imatinib therapy may be especially warranted.

First-line treatment of newly diagnosed elderly patients with chronic myeloid leukemia: current and emerging strategies

Chronic myeloid leukemia (CML) is a disease of the hematopoietic stem cell characterized by a median age at diagnosis of 60-65 years according to most epidemiologic registries. Prior to the tyrosine kinase inhibitor (TKI) era, older age was considered an adverse prognostic factor and was included in two of the most used scoring systems for CML, the Sokal score and the Euro score. Moreover, older age was generally considered a limitation for the use of allogeneic stem-cell transplantation, given the higher toxicity observed. After the introduction of TKIs, age lost much of its prognostic impact in patients in chronic phase (CP), and the EUTOS score, developed in patients treated with imatinib, did not identify age as a risk variable. However, most CML patients require life-long treatment; therefore, as patients age while taking a TKI, the complexity of the management of elderly patients may increase over time. To date, imatinib, the first TKI introduced, and two second-generation TKIs, nilotinib and dasatinib, have been approved in most Western countries for the first-line treatment of CML. These drugs differ in terms of efficacy, safety, and costs; therefore, knowledge of their characteristics is extremely relevant for optimal management of elderly CML patients. We reviewed the impact of age on the first-line treatment of CP CML patients in the TKI era, considering the epidemiology of the disease, the role of comorbidities, and analyzing data from population-based studies and clinical trials.

Impact of comorbidities on overall survival in patients with chronic myeloid leukemia: results of the randomized CML study IV

We studied the influence of comorbidities on remission rate and overall survival (OS) in patients with chronic myeloid leukemia (CML). Participants of the CML Study IV, a randomized 5-arm trial designed to optimize imatinib therapy, were analyzed for comorbidities at diagnosis using the Charlson Comorbidity Index (CCI); 511 indexed comorbidities were reported in 1519 CML patients. Age was an additional risk factor in 863 patients. Resulting CCI scores were as follows: CCI 2, n = 589; CCI 3 or 4, n = 599; CCI 5 or 6, n = 229; and CCI ≥ 7, n = 102. No differences in cumulative incidences of accelerated phase, blast crisis, or remission rates were observed between patients in the different CCI groups. Higher CCI was significantly associated with lower OS probabilities. The 8-year OS probabilities were 93.6%, 89.4%, 77.6%, and 46.4% for patients with CCI 2, 3 to 4, 5 to 6, and ≥7, respectively. In multivariate analysis, CCI was the most powerful predictor of OS, which was still valid after removal of its age-related components. Comorbidities have no impact on treatment success but do have a negative effect on OS, indicating that survival of patients with CML is determined more by comorbidities than by CML itself. OS may therefore be inappropriate as an outcome measure for specific CML treatments. The trial was registered at www.clinicaltrials.gov as #NCT00055874.

Overcoming therapy failure in elderly patients with chronic myeloid leukemia

SUMMARY 

Chronic myeloid leukemia (CML) affects mainly older adults, as median age at diagnosis is 60–65 years. For a long time, survival of elderly CML patients has been shorter compared with younger patients. With the advent of the first tyrosine kinase inhibitor (TKI), imatinib, long-term outcome has significantly improved, including in the elderly, with rates of cytogenetic and molecular responses roughly equal to those attained in the young, as well as manageable toxicity. More recently, second-generation (dasatinib, nilotinib and bosutinib) and third-generation (ponatinib) TKIs were employed in CML patients failing imatinib or other front-line treatments. Despite a shorter follow-up, these TKIs showed remarkable activity in elderly patients. This review focuses on the therapeutic strategies to prevent and overcome treatment failure in elderly CML patients.

Clinical characteristics and therapeutic outcomes of elderly patients with chronic myeloid leukemia: A retrospective multicenter study

AIMS

We aimed to investigate whether older age leads to limitations in the starting dose of imatinib in daily treatment of chronic myeloid leukemia, and to determine the compliance of elderly patients with tyrosine kinase inhibitors (TKI) therapy.

METHODS

Data including the clinical characteristics, therapeutic outcomes and compliance with TKI therapy of elderly patients with chronic myeloid leukemia aged >65 years were collected from 13 institutions in Turkey, retrospectively.

RESULTS

A total of 69 patients (27 [39%] men, 42 [61%] women) were evaluated retrospectively. The median age of the patients was 71 years (range 66-85 years). Of the patients, 66 (96%) were in the chronic phase and three (4.3%) were in the accelerated phase when diagnosed. A total of 63 (91.3%) patients were receiving imatinib as the first-line therapy. The initial dose of imatinib was 400 mg/day in 59 patients (93.6%). Imatinib treatment induced 57 (90.5%) complete hematological responses at 3 months, 29 (46%) complete cytogenetic responses at 6 months and 49 (77.7%) major molecular responses at 12 months. As a result, nilotinib and dasatinib were used in 14 patients as second-line therapy. Second-line TKI induced nine complete hematological responses (64.3%) at 3 months, four complete cytogenetic responses (28.6%) at 12 months and seven major molecular responses (50%) at 18 months. A total of 56 of the patients (81.2%) are still alive. The median overall survival and progression-free survival rates were 35 months (range 1-95 months) and 17 months (range 0.8-95 months), respectively.

CONCLUSION

Elderly patients should receive TKI according to the same guidelines that apply to younger patients.

Older patients with chronic myeloid leukemia (≥65 years) profit more from higher imatinib doses than younger patients: a subanalysis of the randomized CML-Study IV

The impact of imatinib dose on response rates and survival in older patients with chronic myeloid leukemia in chronic phase has not been studied well. We analyzed data from the German CML-Study IV, a randomized five-arm treatment optimization study in newly diagnosed BCR-ABL-positive chronic myeloid leukemia in chronic phase. Patients randomized to imatinib 400 mg/day (IM400) or imatinib 800 mg/day (IM800) and stratified according to age (≥65 years vs. <65 years) were compared regarding dose, response, adverse events, rates of progression, and survival. The full 800 mg dose was given after a 6-week run-in period with imatinib 400 mg/day. The dose could then be reduced according to tolerability. A total of 828 patients were randomized to IM400 or IM800. Seven hundred eighty-four patients were evaluable (IM400, 382; IM800, 402). One hundred ten patients (29 %) on IM400 and 83 (21 %) on IM800 were ≥65 years. The median dose per day was lower for patients ≥65 years on IM800, with the highest median dose in the first year (466 mg/day for patients ≥65 years vs. 630 mg/day for patients <65 years). Older patients on IM800 achieved major molecular remission and deep molecular remission as fast as younger patients, in contrast to standard dose imatinib with which older patients achieved remissions much later than younger patients. Grades 3 and 4 adverse events were similar in both age groups. Five-year relative survival for older patients was comparable to that of younger patients. We suggest that the optimal dose for older patients is higher than 400 mg/day. ClinicalTrials.gov identifier: NCT00055874

Determinants of survival in patients with chronic myeloid leukaemia treated in the new era of oral therapy: findings from a UK population-based patient cohort

OBJECTIVES

To examine contemporary survival patterns in the general population of patients diagnosed with chronic myeloid leukaemia (CML), and to identify patient groups with less than optimal outcomes.

DESIGN

Prospective population-based cohort.

SETTING

The UK's Haematological Malignancy Research Network (catchment population 3.6 million, with >2000 new haematological malignancies diagnosed annually).

PARTICIPANTS

All patients newly diagnosed with CML, from September 2004 to August 2011 and followed up to 31 March 2013.

MAIN OUTCOME MEASURE

Incidence and survival.

RESULTS

With a median diagnostic age of 59 years, the CML age standardised (European) incidence was 0.9/100 000 (95% CIs 0.8 to 0.9), 5-year overall survival was 78.9% (72.3 to 84.0) and 5-year relative survival 88.6% (81.0 to 93.3). The efficacy of treatment across all ages was clearly demonstrated; the relative survival curves for those under 60 and over 60 years being closely aligned. Survival findings were similar for men and women, but varied with deprivation; the age and sex adjusted HR being 3.43 (1.89 to 6.22) for deprivation categories 4-5 (less affluent) versus 1-3 (more affluent). None of these differences were attributable to the biological features of the disease.

CONCLUSIONS

When therapy is freely provided, population-based survival for CML is similar to that reported in clinical trials, and age loses its prognostic significance. However, although most of the patients with CML now experience close to normal lifespans, those living in more deprived areas tend to have poorer outcomes, despite receiving the same clinical care. A significant improvement in overall population outcomes could be achieved if these socioeconomic differences, which may reflect the treatment compliance, could be eliminated.

Impact of comorbidities on the treatment of chronic myeloid leukemia with tyrosine-kinase inhibitors

The median age at diagnosis of chronic myeloid leukemia (CML) is between 60 and 65 years in most epidemiologic registries. Rather than age per se, a comprehensive evaluation of comorbidities may describe more properly the general clinical status of a patient. Tyrosine-kinase inhibitors (TKIs) have a different tolerability profile, and some adverse events (AEs) are peculiar of each drug, in particular, in presence of predisposing factors (comorbidities, concomitant medications). This article will review the impact of comorbidities in the safety and outcome of CML patients treated with TKIs. We will explore how the comorbidity status may be considered, together with CML-related factors, in the selection of the TKI in order to optimize treatment.