Efficacy and safety of dasatinib in imatinib-resistant or -intolerant patients with chronic myeloid leukemia in blast phase

Management and outcome of patients with chronic myeloid leukemia in blast phase in the tyrosine kinase inhibitor era - analysis of the European LeukemiaNet Blast Phase Registry

Blast phase (BP) of chronic myeloid leukemia (CML) still represents an unmet clinical need with a dismal prognosis. Due to the rarity of the condition and the heterogeneity of the biology and clinical presentation, prospective trials and concise treatment recommendations are lacking. Here we present the analysis of the European LeukemiaNet Blast Phase Registry, an international collection of the clinical presentation, treatment and outcome of blast phases which had been diagnosed in CML patients after 2015. Data reveal the expected heterogeneity of the entity, lacking a clear treatment standard. Outcomes remain dismal, with a median overall survival of 23.8 months (median follow up 27.8 months). Allogeneic stem cell transplantation (alloSCT) increases the rate of deep molecular responses. De novo BP and BP evolving from a previous CML do show slightly different features, suggesting a different biology between the two entities. Data show that outside clinical trials and in a real-world setting treatment of blast phase is individualized according to disease- and patient-related characteristics, with the aim of blast clearance prior to allogeneic stem cell transplantation. AlloSCT should be offered to all patients eligible for this procedure.

Hematological Adverse Events with Tyrosine Kinase Inhibitors for Chronic Myeloid Leukemia: A Systematic Review with Meta-Analysis

Chronic myeloid leukemia (CML) is treated with tyrosine kinase inhibitors (TKI) that target the pathological BCR-ABL1 fusion oncogene. The objective of this statistical meta-analysis was to assess the prevalence of other hematological adverse events (AEs) that occur during or after predominantly first-line treatment with TKIs. Data from seventy peer-reviewed, published studies were included in the analysis. Hematological AEs were assessed as a function of TKI drug type (dasatinib, imatinib, bosutinib, nilotinib) and CML phase (chronic, accelerated, blast). AE prevalence aggregated across all severities and phases was significantly different between each TKI (p < 0.05) for anemia-dasatinib (54.5%), bosutinib (44.0%), imatinib (32.8%), nilotinib (11.2%); neutropenia-dasatinib (51.2%), imatinib (29.8%), bosutinib (14.1%), nilotinib (14.1%); thrombocytopenia-dasatinib (62.2%), imatinib (30.4%), bosutinib (35.3%), nilotinib (22.3%). AE prevalence aggregated across all severities and TKIs was significantly (p < 0.05) different between CML phases for anemia-chronic (28.4%), accelerated (66.9%), blast (55.8%); neutropenia-chronic (26.7%), accelerated (63.8%), blast (36.4%); thrombocytopenia-chronic (33.3%), accelerated (65.6%), blast (37.9%). An odds ratio (OR) with 95% confidence interval was used to compare hematological AE prevalence of each TKI compared to the most common first-line TKI therapy, imatinib. For anemia, dasatinib OR = 1.65, [1.51, 1.83]; bosutinib OR = 1.34, [1.16, 1.54]; nilotinib OR = 0.34, [0.30, 0.39]. For neutropenia, dasatinib OR = 1.72, [1.53, 1.92]; bosutinib OR = 0.47, [0.38, 0.58]; nilotinib OR = 0.47, [0.42, 0.54]. For thrombocytopenia, dasatinib OR = 2.04, [1.82, 2.30]; bosutinib OR = 1.16, [0.97, 1.39]; nilotinib OR = 0.73, [0.65, 0.82]. Nilotinib had the greatest fraction of severe (grade 3/4) hematological AEs (30%). In conclusion, the overall prevalence of hematological AEs by TKI type was: dasatinib > bosutinib > imatinib > nilotinib. Study limitations include inability to normalize for dosage and treatment duration.

Pharmacokinetics and safety of dasatinib and its generic: a phase I bioequivalence study in healthy Chinese subjects

BACKGROUND

Dasatinib (Sprycel®) is a tyrosine kinase inhibitor for treating chronic myeloid leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia.

RESEARCH DESIGN & METHODS

We designed a clinical study to demonstrate that the dasatinib tablet (YiNiShu®) (Chia Tai Tianqing Pharmaceutical Group Co., Ltd) and Dasatinib (Bristol Myers Squibb) were bioequivalent under fasting and fed conditions. The whole study was structured into the fasting trial and the postprandial trial. Each period, subjects were given 50 mg dasatinib or its generic. The RSABE (reference scale average bioequivalence) and ABE (average bioequivalence) methods were employed to assess bioequivalence by pharmacokinetics (PK) parameters for a highly variable drug.

RESULTS

32 and 24 eligible volunteers were enrolled in the fasting and postprandial trials, respectively. In the fasting trial, the RSABE method was performed, and point estimates of C_max, AUC_0-t, and AUC_0-∞ met the bioequivalence criteria. In the postprandial trial, the ABE method was performed, and the 90% CI of the geometric mean ratio (GMR) for PK parameters met the requirements of bioequivalence standards.

CONCLUSION

The results proved that the PK parameters of the two drugs were similar and bioequivalent, indicating that both drugs had a good safety profile.

CLINICAL TRIAL REGISTRATION

This trial was registered in ClinicalTrials.gov (Number: NCT05640804) and Drug Clinical Trial Registration and Information Disclosure Platform (Number: CTR20181708).

Treatment of blast phase chronic myeloid leukaemia: A rare and challenging entity

Despite the success of BCR-ABL-specific tyrosine kinase inhibitors (TKIs) such as imatinib in chronic phase (CP) chronic myeloid leukaemia (CML), patients with blast phase (BP)-CML continue to have a dismal outcome with median survival of less than one year from diagnosis. Thus BP-CML remains a critical unmet clinical need in the management of CML. Our understanding of the biology of BP-CML continues to grow; genomic instability leads to acquisition of mutations which drive leukaemic progenitor cells to develop self-renewal properties, resulting in differentiation block and a poor-prognosis acute leukaemia which may be myeloid, lymphoid or bi-phenotypic. Similar advances in therapy are urgently needed to improve patient outcomes; however, this is challenging given the rarity and heterogeneity of BP-CML, leading to difficulty in designing and recruiting to prospective clinical trials. This review will explore the treatment of BP-CML, evaluating the data for TKI therapy alone, combinations with intensive chemotherapy, the role of allogeneic haemopoietic stem cell transplantation, the use of novel agents and clinical trials, as well as discussing the most appropriate methods for diagnosing BP and assessing response to therapy, and factors predicting outcome.

Differential prognostic impact of stratified additional chromosome abnormalities on disease progression among Malaysian chronic myeloid leukemia patients undergoing treatment with imatinib mesylate

The emergence of additional chromosome abnormalities (ACAs) in chronic myeloid leukemia (CML) patients during treatment with a tyrosine kinase inhibitor (TKI) regime is generally associated with resistance to treatment and a sign of disease progression to accelerated phase or blast phase. We report the type, frequency, and differential prognostic impact of stratified ACAs with treatment response in 251 Malaysian CML patients undergoing TKI therapy. ACAs were observed in 40 patients (15.9%) of which 7 patients (17.5%) showed ACAs at time of initial diagnosis whereas 33 patients (82.5%) showed ACAs during the course of IM treatment. In order to assess the prognostic significance, we stratified the CML patients with ACAs into four groups, group 1 (+8/+Ph), group 2 (hypodiploidy), group 3 (structural/complex abnormalities); group 4 (high-risk complex abnormalities), and followed up the disease outcome of patients. Group 1 and group 2 relatively showed good prognosis while patients in group 3 and group 4 had progressed or transformed to AP or blast phase with a median survival rate of 12 months after progression. Novel ACAs consisting of rearrangements involving chromosome 11 and chromosome 12 were found to lead to myeloid BP while ACAs involving the deletion of 7q or monosomy 7 led toward a lymphoid blast phase. There was no evidence of group 2 abnormalities (hypodiploidy) contributing to disease progression. Compared to group 1 abnormalities, CML patients with group 3 and group 4 abnormalities showed a higher risk for disease progression. We conclude that the stratification based on individual ACAs has a differential prognostic impact and might be a potential novel risk predictive system to prognosticate and guide the treatment of CML patients at diagnosis and during treatment.

Chronic Myeloid Leukemia: Part II-Cost of Care Among Patients in Advanced Phases or Later Lines of Therapy in Chronic Phase in the United States from a Commercial Perspective

Background: Tyrosine kinase inhibitors (TKIs) are the standard-of-care treatment for chronic myeloid leukemia in chronic phase (CML-CP). Despite advances in therapy, there remains a proportion of patients with CML-CP that are refractory/intolerant to TKIs, and these patients cycle through multiple lines of therapy. Moreover, even with TKIs, some patients progress to accelerated phase/blast crisis (AP/BC), which is associated with particularly poor clinical outcomes. Objectives: To describe real-world treatment patterns, healthcare resource utilization (HRU), and costs of patients with CML-CP reaching later lines of therapy or progressing to AP/BC in the United States. Methods: Adult CML patients from administrative claims data (January 1, 2000-June 30, 2019) were classified by health state: on third-line (CML-CP On Treatment), on fourth or later lines (CML-CP Post-Discontinuation), or progressed to AP/BC (CML-AP/BC). Outcomes were assessed by health state. Results: There were 296 (4620 patient-months), 83 (1644 patient-months), and 949 (25 593 patient-months) patients classified in the CML-CP On Treatment, CML-CP Post-Discontinuation, and CML-AP/BC cohorts, respectively. Second-generation TKIs (nilotinib, dasatinib, and bosutinib) were most commonly used in the CML-CP On Treatment (69.1% of patient-months) and CML-CP Post-Discontinuation cohorts (59.1% of patient-months). Three-month outpatient incidence rates (IRs) were 7.6, 8.3, and 7.0 visits in the CML-CP On Treatment, CML-CP Post-Discontinuation, and CML-AP/BC cohort, respectively, with mean costs of $597 per service. Three-month inpatient IRs were 0.6, 0.7, and 1.4 days in the CML-CP On Treatment, CML-CP Post-Discontinuation, and CML-AP/BC cohort, respectively, with mean costs of $5892 per day. Mean hematopoietic stem cell transplantation cost was $352 333; mean 3-month terminal care cost was $107 013. Discussion: Cost of CML care is substantial among patients with CML reaching third-line, fourth or later lines, or progressing to AP/BC, suggesting that the disease is associated with a significant economic and clinical burden. From third-line to fourth or later lines, HRU was observed to increase, and the incidence of inpatient days was particularly high for those who progressed to AP/BC. Conclusion: In this study, patients with CML cycling through TKIs in later lines of therapy or progressing to AP/BC experienced substantial HRU and costs, suggesting unmet treatment needs.

Treatment of Gastrointestinal Stromal Tumors (GISTs): A Focus on Younger Patients

Gastrointestinal stromal tumors (GISTs) originate from Cajal's cells and are the most common mesenchymal neoplasms of the gastrointestinal tract. GISTs in young adults, i.e., patients before the age of 40, are rare and differ from those in older patients and GISTs in children in terms of the molecular and clinical features, including the location and type of mutations. They often harbor other molecular abnormalities than KIT and PDGFRA mutations (wild-type GISTs). The general principles of therapeutic management in young patients are the same as in the elderly. Considering some differences in molecular abnormalities, molecular testing should be the standard procedure to allow appropriate systemic therapy if needed. The optimal treatment strategy should be established by a multidisciplinary team experienced in sarcoma treatment. The impact of treatment on the quality of life and daily activities, including the impact on work, pregnancy, and fertility, in this patient population should be especially taken into consideration.

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.

Unilateral Interstitial Lung Disease with Contralateral Effusion: Unusual Case Report of Dasatinib Toxicity

Dasatinib is a second-generation tyrosine kinase inhibitor (TKI) used in chronic myelogenous leukemia (CML). While pleural effusion due to Dasatinib is well described in the literature, interstitial lung disease (ILD) caused by it is rare. A 60-year-old gentleman was on treatment with 100 mg of tablet Dasatinib per day for chronic myeloid leukemia. He presented to the outpatient department with history of progressive breathlessness over 2 months. High-resolution computerized tomography (HRCT) thorax revealed mild right-sided effusion and non-specific interstitial pneumonia (NSIP) pattern of ILD in the left lower lobe. Thoracocentesis of the right-sided pleural effusion showed exudative and lymphocytic rich pleural effusion. The effusion was negative for malignant cells or infection. Biopsy of the left lower lobe was consistent with the diagnosis of ILD. He was started on prednisolone which was gradually tapered and stopped. At 3 months, there was a complete resolution of the ILD and pleural effusion. Clinicians need to be aware about the pleuroparenchymal toxicities of Dasatinib. Early diagnosis and treatment with steroids can lead to complete resolution of the signs and symptoms.

Chronic myeloid leukaemia

Tyrosine-kinase inhibitors have changed the natural history of chronic myeloid leukaemia in such a way that patients with adequate access to these agents, who are properly managed, and who respond well to this treatment can expect a near-normal life expectancy. Achieving this goal requires an adequate understanding of the patient's treatment goals, careful monitoring for the achievement of optimal response hallmarks, implementation of proper interventions according to the attainment of such endpoints, adequate recognition and management of adverse events, and acknowledgment of the relevance of comorbidities. Treatment with tyrosine-kinase inhibitors, once considered lifelong, has become terminable for at least some patients, and promising new agents are emerging for those whose disease does not respond to any of the multiple therapeutic options currently available. If these advances reach all patients with chronic myeloid leukaemia, cure might eventually become a reality in most instances.

[Treatment status of tyrosine kinase inhibitors in Chinese patients with chronic myeloid leukemia in 2020]

Objective: To investigate the current status of treatment choice and responses in patients with chronic myeloid leukemia (CML) in China. Methods: From the end of April to mid-May in 2020, a cross-sectional survey, by filling out a survey questionnaire, was conducted to explore the first-line choice of tyrosine kinase inhibitors (TKI) , current medications, drug switch and major molecular responses (MMR) as well as the variables associated with them in patients in China. Results: Data of 2933 respondents with CML from 31 provinces, municipalities, and autonomous regions across the country were included in this study. 1683 respondents (57.4%) were males. Median age was 38 (16-87) years old. 2481 respondents (84.6%) received imatinib as first-line TKI; 1803 (61.5%) , the original new drug (branded drug) . When completing the questionnaire, 1765 respondents (60.2%) were receiving imatinib; 1791 (61.1%) , branded drug. 1185 respondents (40.4%) had experienced TKI switch. With a median follow-up of 45 (3-227) months, 1417 of 1944 (72.9%) respondents with newly diagnosed CML in the chronic phase achieved MMR. Multivariate analysis showed that the respondents with urban household registration (OR=0.6, 95%CI 0.5-0.8, P<0.001) , ≥ bachelor degree (OR=0.5, 95%CI 0.4-0.7, P<0.001) , and in the advanced phase at diagnosis (OR=0.5, 95%CI 0.3-0.8, P=0.001) less preferred Chinese generic TKI, while the respondents from the central region in China more preferred Chinese generic TKI more than those from the eastern region (OR=1.7, 95%CI 1.4-2.0, P<0.001) . Moreover, the respondents in the advanced phase at diagnosis more preferred second-generation TKI (OR=5.4, 95%CI 3.6-8.2, P<0.001) ; those ≥60 years old, less preferred second-generation TKI (OR=0.4, 95%CI 0.2-0.7, P=0.002) . Being in the advanced phase at diagnosis (OR=2.2, 95%CI 1.6-3.2, P<0.001) , first-line choice of imatinib (OR=2.0, 95%CI 1.6-2.6, P<0.001) or Chinese generic drugs (OR=1.3, 95%CI 1.1-1.6, P=0.002) , longer interval from diagnose of CML to starting TKI treatment (OR=1.2, 95%CI 1.1-1.2, P<0.001) and longer duration of TKI therapy (OR=1.1, 95%CI 1.0-1.1, P<0.001) were significantly associated with TKI switch; urban household registration (OR=0.7, 95%CI 0.6-0.8, P<0.001) , ≥MMR (OR=0.6, 95%CI 0.5-0.8, P<0.001) and unknown response (OR=0.7, 95%CI 0.6-0.9, P=0.003) , no TKI switch. Female sex (OR=1.4, 95%CI 1.1-1.7, P=0.003) , urban household registration (OR=1.6, 95%CI 1.3-2.0, P<0.001) , front-line imatinib therapy (OR=1.4, 95%CI 1.1-1.9, P=0.016) and longer duration of TKI treatment (OR=1.2, 95%CI 1.2-1.3, P<0.001) were significantly associated with achieving a MMR or better response; age ≥ 60 years old (OR=0.7, 95%CI 0.4-1.0, P=0.047) and TKI switch (OR=0.6, 95%CI 0.5-0.7, P<0.001) , achieving no MMR. Conclusions: By 2020, the majority of Chinese CML patients received imatinib as the fist-line TKI therapy and continue to take it. More than half of TKIs were branded drugs. Socio-demographic characteristics and clinical variables affect their TKI choice, drug switch, and treatment response.

Treatment of Metastatic Gastrointestinal Stromal Tumors (GIST): A Focus on Older Patients

Gastrointestinal stromal tumors (GIST) originating in the Cajal cells are the most common mesenchymal neoplasms of the gastrointestinal tract. The median age of patients with this diagnosis is 65 years, and over 20% of cases affect people over the age of 70 years. The effectiveness and tolerability of systemic treatment with tyrosine kinase inhibitors in older patients with GIST seem to be similar to that in younger patients, but some studies have shown that treatment of older patients is suboptimal. Disability, frailty, comorbidities, and concomitant medications may influence treatment decisions, and toxicities also more often lead to treatment discontinuation. The known safety profile and oral administration route of the tyrosine kinase inhibitors used in GIST may allow maximization of treatment and the best efficacy, especially in older patients. This review summarizes the efficacy data for the systemic treatment of GIST, including data for older patients and from real-world experiences, if available and significant. The reported safety data and general rules for toxicity management, including appropriate patient selection and the need for careful monitoring during treatment, are also discussed.

Outcome of patients with chronic myeloid leukemia in lymphoid blastic phase and Philadelphia chromosome-positive acute lymphoblastic leukemia treated with hyper-CVAD and dasatinib

BACKGROUND

Dasatinib monotherapy has demonstrated modest clinical activity in chronic myeloid leukemia in lymphoid blastic phase (CML-LBP). The outcome of Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL) has dramatically improved with hyperfractionated cyclophosphamide, vincristine sulfate, doxorubicin hydrochloride, and dexamethasone (hyper-CVAD) in combination with tyrosine kinase inhibitors (TKIs).

METHODS

The authors reviewed 85 patients (23 with CML-LBP and 62 with newly diagnosed Ph-positive ALL) who received hyper-CVAD plus dasatinib.

RESULTS

In the CML-LBP cohort, 19 had prior chronic myeloid leukemia as chronic phase (n = 17; 74%), accelerated phase (n = 1; 4%), or myeloid blastic phase (n = 1; 4%); 4 (17%) presented with de novo CML-LBP. The BCR-ABL1 transcript was p210 in 22 patients (96%) and p190 in 1 patient (4%). In the Ph-positive ALL cohort, p210 and p190 transcripts were detected in 13 patients (21%) and 48 patients (77%), respectively. Patients with CML-LBP were less likely to achieve deep molecular remission than patients with Ph-positive ALL: the major molecular response (MMR) rates were 70% and 95%, respectively (P = .007), and the complete molecular response (CMR) rates were 55% and 74%, respectively (P = .16). Survival outcomes were similar for CML-LBP and Ph-positive ALL: the 5-year overall survival (OS) rates were 59% and 48%, respectively (P = .97). Allogeneic stem cell transplantation was associated with a better outcome in CML-LBP (5-year OS rate, 88% vs 57%; P = .04). In Ph-positive ALL, the outcome was driven by deeper molecular remission: the 5-year OS rates were 63% and 25% with CMR and MMR, respectively (P = .002).

CONCLUSIONS

The outcome of CML-LBP has improved with hyper-CVAD plus dasatinib therapy with survival comparable to that of Ph-positive ALL. Further improvement may be achieved with the use of novel TKIs and targeted agents.

Early Management of CML

PURPOSE OF REVIEW

The marked improvement in clinical outcomes for patients with chronic myeloid leukaemia (CML) can be solely attributed to the introduction of targeted therapies against the fusion oncoprotein, BCR-ABL1. However, patient responses, although generally positive, remain heterogenous. Careful drug selection, ensuring the optimal TKI, is chosen for each patient and involves a complex decision process which incorporates consideration of numerous factors.

RECENT FINDINGS

For some patients, with disease characteristics that indicate adverse intrinsic disease biology, more potent BCR-ABL1 inhibition is often appropriate, whereas other patients with major co-morbidities will benefit from a less aggressive approach to avoid life-shortening toxicities. For the vast majority of patients, the long-term goal of therapy will be the achievement of a deep molecular response and subsequent treatment-free remission and this consideration will play a large part in the drug selection process. We explore early management of CML, from the first presentation through to frontline therapy selection.

Management of Chronic Myeloid Leukemia in Advanced Phase

Management of chronic myeloid leukemia (CML) in advanced phases remains a challenge also in the era of tyrosine kinase inhibitors (TKIs) treatment. Cytogenetic clonal evolution and development of resistant mutations represent crucial events that limit the benefit of subsequent therapies in these patients. CML is diagnosed in accelerated (AP) or blast phase (BP) in <5% of patients, and the availability of effective treatments for chronic phase (CP) has dramatically reduced progressions on therapy. Due to smaller number of patients, few randomized studies are available in this setting and evidences are limited. Nevertheless, three main scenarios may be drawn: (a) patients diagnosed in AP are at higher risk of failure as compared to CP patients, but if they achieve optimal responses with frontline TKI treatment their outcome may be similarly favorable; (b) patients diagnosed in BP may be treated with TKI alone or with TKI together with conventional chemotherapy regimens, and subsequent transplant decisions should rely on kinetics of response and individual transplant risk; (c) patients in CP progressing under TKI treatment represent the most challenging population and they should be treated with alternative TKI according to the mutational profile, optional chemotherapy in BP patients, and transplant should be considered in suitable cases after return to second CP. Due to lack of validated and reliable markers to predict blast crisis and the still unsatisfactory results of treatments in this setting, prevention of progression by careful selection of frontline treatment in CP and early treatment intensification in non-optimal responders remains the main goal. Personalized evaluation of response kinetics could help in identifying patients at risk for progression.

[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.

Incidence and outcome of BCR-ABL mutated chronic myeloid leukemia patients who failed to tyrosine kinase inhibitors

Purpose

To assess the incidence of BCR‐ABL kinase domain (KD) mutation detection and its prognostic significance in chronic phase chronic myeloid leukemia (CP‐CML) patients treated with tyrosine kinase inhibitors (TKIs).

Patients and Methods

We analyzed characteristics and outcome of 253 CP‐CML patients who had at least one mutation analysis performed using direct sequencing. Of them, 187 patients were early CP (ECP) and 66 were late CP late chronic phase (LCP) and 88% were treated with Imatinib as first‐line TKI.

Results

Overall, 80 (32%) patients harbored BCR‐ABL KD mutations. A BCR‐ABL KD mutation was identified in 57% of patients, who progressed to accelerated or blastic phases (AP‐BP), and 47%, 29%, 35%, 16% and 26% in patients in CP‐CML at the time of mutation analysis who lost a complete hematologic response, failed to achieve or loss of a prior complete cytogenetic and major molecular response, respectively.

Overall survival and cumulative incidence of CML‐related death were significantly correlated with the disease phase whatever the absence or presence of a mutation was and for the latter the mutation subgroup (T315I vs P‐loop vs non‐T315I non‐P‐loop) (P<.001). Considering patients who were in CP at the time of mutation analysis, LCP mutated patients had a significantly worse outcome than ECP‐mutated patients despite a lower incidence of T315I and P‐loop mutations (P<.001). With a median follow‐up from mutation analysis to last follow‐up of 5 years, T315I and P‐loop mutations were not associated with a worse outcome in ECP patients (P = .817).

Conclusion

Our results suggest that early mutation detection together with accessibility to 2nd and 3rd generation TKIs have reversed the worst outcome associated with BCR‐ABL KD mutations whatever the mutation subgroup in CP‐CML patients.

TKI-Related Platelet Dysfunction Does Not Correlate With Bleeding in Patients With Chronic Phase-Chronic Myeloid Leukemia With Complete Hematological Response

Bleeding has been reported in patients with chronic myeloid leukemia (CML) using tyrosine kinase inhibitors (TKIs). In this study, we aimed to evaluate platelet functions and associated bleeding symptoms in patients with CML using TKIs. A standardized questionnaire that was developed for inherited bleeding disorders (ISTH/SSC Bleeding Assessment Tool) was used to score bleeding symptoms in 68 chronic phase patients with CML receiving imatinib (n = 47), dasatinib (n = 15), or nilotinib (n = 6). Light transmission aggregometry was used for platelet function testing. None of the patients had major bleeding (score > 3). Minor bleeding was observed in 25.6% and 20% of the patients in imatinib and dasatinib treatment groups. Impaired/decreased platelet aggregation was observed in 29.8% of imatinib treatment group, 50% of nilotinib group, and 40% of dasatinib group. A secondary aggregation abnormality compatible with the release defect was observed in 26% of patients with CML; 25.5%, 33.3%, and 16.7% of patients receiving imatinib, dasatinib, and nilotinib, respectively. No correlation was found between bleeding symptoms and the impaired platelet function. We can conclude that TKIs may impair in vitro platelet aggregation but this impairment is not associated with bleeding diathesis.

Efficient disruption of bcr-abl gene by CRISPR RNA-guided FokI nucleases depresses the oncogenesis of chronic myeloid leukemia cells

Background

The bcr-abl fusion gene encodes BCR-ABL oncoprotein and plays a crucial role in the leukemogenesis of chronic myeloid leukemia (CML). Current therapeutic methods have limited treatment effect on CML patients with drug resistance or disease relapse. Therefore, novel therapeutic strategy for CML is essential to be explored and the CRISPR RNA-guided FokI nucleases (RFNs) meet the merits of variable target sites and specificity of cleavage enabled its suitability for gene editing of CML. The RFNs provide us a new therapeutic direction to obliterate this disease.

Methods

Guide RNA (gRNA) expression plasmids were constructed by molecular cloning technique. The modification rate of RFNs on bcr-abl was detected via NotI restriction enzyme digestion and T7 endonuclease 1 (T7E1) assay. The expression of BCR-ABL and its downstream signaling molecules were determined by western blotting. The effects of RFNs on cell proliferation and apoptosis of CML cell lines and CML stem/progenitor cells were evaluated by CCK-8 assay and flow cytometry. In addition, murine xenograft model was adopted to evaluate the capacity of RFNs in attenuating the tumorigenic ability of bcr-abl.

Results

The RFNs efficiently disrupted bcr-abl and prematurely terminated its translation. The destruction of bcr-abl gene suppressed cell proliferation and induced cell apoptosis in CML lines and in CML stem/progenitor cells. Moreover, the RFNs significantly impaired the leukemogenic capacity of CML cells in xenograft model.

Conclusion

These results illustrate that the RFNs can target to disrupt bcr-abl gene and may provide a new therapeutic option for CML patients affiliated by drug resistance or disease relapse.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1229-5) contains supplementary material, which is available to authorized users.

Efficient disruption of bcr-abl gene by CRISPR RNA-guided FokI nucleases depresses the oncogenesis of chronic myeloid leukemia cells

BACKGROUND

The bcr-abl fusion gene encodes BCR-ABL oncoprotein and plays a crucial role in the leukemogenesis of chronic myeloid leukemia (CML). Current therapeutic methods have limited treatment effect on CML patients with drug resistance or disease relapse. Therefore, novel therapeutic strategy for CML is essential to be explored and the CRISPR RNA-guided FokI nucleases (RFNs) meet the merits of variable target sites and specificity of cleavage enabled its suitability for gene editing of CML. The RFNs provide us a new therapeutic direction to obliterate this disease.

METHODS

Guide RNA (gRNA) expression plasmids were constructed by molecular cloning technique. The modification rate of RFNs on bcr-abl was detected via NotI restriction enzyme digestion and T7 endonuclease 1 (T7E1) assay. The expression of BCR-ABL and its downstream signaling molecules were determined by western blotting. The effects of RFNs on cell proliferation and apoptosis of CML cell lines and CML stem/progenitor cells were evaluated by CCK-8 assay and flow cytometry. In addition, murine xenograft model was adopted to evaluate the capacity of RFNs in attenuating the tumorigenic ability of bcr-abl.

RESULTS

The RFNs efficiently disrupted bcr-abl and prematurely terminated its translation. The destruction of bcr-abl gene suppressed cell proliferation and induced cell apoptosis in CML lines and in CML stem/progenitor cells. Moreover, the RFNs significantly impaired the leukemogenic capacity of CML cells in xenograft model.

CONCLUSION

These results illustrate that the RFNs can target to disrupt bcr-abl gene and may provide a new therapeutic option for CML patients affiliated by drug resistance or disease relapse.

Myelomastocytic Blast Cell Crisis in Resistant Tyrosine Kinase Inhibitor Chronic Myelogenous Leukemia: Case Report and Review of Literature

We present the clinical case of a 29-year-old male with a diagnosis of chronic myeloid leukemia (CML) in high-risk chronic phase since February 2010. He started treatment with imatinib at a dose of 400 mg obtaining a hematologic response early but without reaching a cytogenetic response in month 18. Then, dasatinib was prescribed. The BCR-ABL transcription level of 58% was documented. It was decided to start treatment with nilotinib but in March 2017 we diagnosed a progression to blast crisis (BC) of myeloid origin with a bone marrow study that documented 72% of blasts with normal karyotype, also very striking, the concomitant skin infiltration, bone lesions of lytic type and hypercalcemia that required the use of zoledronic acid as an emergency. At the end of chemotherapy induction with 7 + 3 (seven days of cytarabine and three days of idarubicin) chemotherapy associated with bosutinib for 14 days and after several infectious complications, we documented a percentage of blasts by flow cytometry of 29% in the bone marrow and the existence of 46% of cells with basophilic characteristics versus mast cells. A basophilic transformation was suspected versus aggressive systemic mastocytosis with a clonal, nonmastocytic hematological disorder. Levels of serum tryptase and mutation D816V C KIT were requested, which were not possible to perform. Treatment with CLAG-M was proposed, however, the patient died early with hyperleukocytosis and severe thrombocytopenia with central nervous system bleeding.

Treatment of Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia

OPINION STATEMENT

With the introduction of tyrosine kinase inhibitors (TKIs) in the management of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL), the prognosis of patients has improved dramatically. Currently, the standard of care in the frontline setting for fit patients is TKI in combination with chemotherapy. Age-adjusted chemotherapy or corticosteroids alone have been used with TKIs in elderly patients with comorbidities with modest long-term benefit. The primary goal of treatment is the achievement of early deep molecular remission as the achievement of complete molecular remission (CMR) at 3 months has been demonstrated to be predictive of higher long-term survival. The probability of attaining this goal by a more potent TKIs like dasatinib or ponatinib is higher, thus we recommend the use of second- or third-generation TKIs over imatinib. Clinicians should be aware of possible fatal cardiovascular events mainly related to ponatinib. Allogeneic hematopoietic stem cell transplantation (alloHSCT) should still be considered in first remission, especially for younger patients treated with imatinib combination therapy. A subset of patients achieving CMR at 3 months may be able to continue consolidation and maintenance with chemotherapy and TKI without the need for alloHSCT. Because of higher risk of relapses in the central nervous system, intrathecal chemoprophylaxis is mandatory for all patients. New strategies incorporating novel agents, such as antibody-drug conjugates, bispecific monoclonal antibodies, potent TKIs, and CAR T cells are under investigation.

Dasatinib

Dasatinib is an oral available short-acting inhibitor of multiple tyrosine kinases. It was designed to inhibit ABL and SRC, but also has activity in multiple other kinases, including c-KIT, PDGFR-α, PDGFR-β, and ephrin receptor kinases. Dasatinib is a very potent inhibitor of BCR-ABL and an effective treatment for the BCR-ABL-driven diseases chronic myeloid leukemia (CML) and Philadelphia-chromosome-positive acute lymphoblastic leukemia (Ph+ ALL), characterized by the constitutively active tyrosine kinase, BCR-ABL. Dasatinib is approved for the treatment of CML (all phases) including children and for the treatment of Ph+ ALL, resistant or intolerant to prior imatinib treatment. Randomized trials in CML comparing dasatinib with imatinib show that first-line dasatinib causes significantly deeper and faster molecular remissions. In accelerated and blastic phase CML, as well as in Ph+ ALL, dasatinib frequently induces complete hematologic and cytogenetic remissions even in imatinib pretreated patients. Remissions however are often short. Dasatinib is administered independent of food intake as a once-daily dose of 100 mg in chronic phase CML and 140 mg in Ph+ ALL or blastic phase. Side effects of dasatinib are frequent but mostly moderate and manageable and include cytopenias and pleural effusions. The review presents the preclinical and clinical activity of dasatinib with a focus on clinical studies in CML.

Cytogenetics-based risk prediction of blastic transformation of chronic myeloid leukemia in the era of TKI therapy

The high fatality of patients with blast phase (BP) chronic myeloid leukemia (CML) necessitates identification of high-risk (HR) patients to prevent onset of BP. Here, we investigated the risk of BP based on additional chromosomal abnormality (ACA) profiles in a cohort of 2326 CML patients treated with tyrosine kinase inhibitors (TKIs). We examined the time intervals from initial diagnosis to ACA emergence (interval 1), from ACA emergence to onset of BP (interval 2), and survival after onset of BP (interval 3). Based on BP risk associated with each ACA, patients were stratified into intermediate-1, intermediate-2, and HR groups, with a median duration of interval 2 of unreached, 19.2 months, and 1.9 months, respectively. There was no difference in durations of intervals 1 or 3 among 3 groups. Including patients without ACAs who formed the standard-risk group, the overall 5-year cumulative probability of BP was 9.8%, 28.0%, 41.7%, and 67.4% for these 4 groups, respectively. The pre-BP disease course in those who developed BP was similar regardless of cytogenetic alterations, and 84.4% of BP patients developed BP within the first 5 years of diagnosis. In summary, interval 2 is the predominant determinant of BP risk and patient outcome. By prolonging the duration of interval 2, TKI therapy mitigates BP risk associated with low-risk ACAs or no ACAs but does not alter the natural course of CML with HR ACAs. Thus, we have identified a group of patients who have HR of BP and may benefit from timely alternative treatment to prevent onset of BP.

Azacytidine in combination with tyrosine kinase inhibitors induced durable responses in patients with advanced phase chronic myelogenous leukemia

Although the tyrosine kinase inhibitor (TKI) era has brought great improvement in outcome in chronic myelogenous leukemia (CML), prognosis of accelerated phase or myeloid blast crisis patients or of de novo Philadelphia chromosome-positive acute myeloid leukemia remains poor. We conducted a retrospective study on patients with advanced phase disease treated with a TKI and azacytidine. Sixteen patients were eligible. Median age was 64.9 years, the median number of previous therapies was 2.5 lines, and median follow-up was 23.1 months. Hematologic response (HR) rate was 81.3%. Median overall survival (OS), event free survival and relapse-free survival (RFS) were 31.5, 23.3, and 32.2 months, respectively. All except one patient were treated as out-patients after the first cycle. Five patients were bridged to allogenic hematopoietic stem cells transplant. The combination of a TKI and azacytidine is a safe and efficient regiment for patients with CML patients in advanced phases.

Ponatinib in chronic myeloid leukemia (CML): Consensus on patient treatment and management from a European expert panel

Five tyrosine kinase inhibitors (TKIs) are currently approved in the European Union for treatment of chronic myeloid leukemia (CML) and all have considerable overlap in their indications. While disease-specific factors such as CML phase, mutational status, and line of treatment are key to TKI selection, other important features must be considered, such as patient-specific comorbidities and TKI safety profiles. Ponatinib, the TKI most recently approved, has demonstrated efficacy in patients with refractory CML, but is associated with an increased risk of arterial hypertension, sometimes severe, and serious arterial occlusive and venous thromboembolic events. A panel of European experts convened to discuss their clinical experience in managing patients with CML. Based on the panel discussions, scenarios in which a CML patient may be an appropriate candidate for ponatinib therapy are described, including presence of the T315I mutation, resistance to other TKIs without the T315I mutation, and intolerance to other TKIs.

The incidence and natural history of dasatinib complications in the treatment of chronic myeloid leukemia

Dasatinib has shown superiority over imatinib in achieving molecular responses (MRs) in chronic phase chronic myeloid leukemia but with a different toxicity profile, which may impact its overall benefit. Reported toxicities include pleural effusions and pulmonary hypertension, and although the incidence of these events is well described, response to therapy and impact of dose modifications on toxicity has not been comprehensively characterized in a real-world setting. We retrospectively reviewed the incidence of dasatinib adverse events in 212 chronic phase chronic myeloid leukemia patients at 17 Australian institutions. Adverse events were reported in 116 patients (55%), most commonly pleural effusions (53 patients, 25%), which was the predominant cause of permanent drug cessation. Age and dose were risk factors for pleural effusion (P < .01 and .047, respectively). Recurrence rates were higher in those who remained on 100 mg compared with those who dose reduced (P = .041); however, recurrence still occurred at 50 mg. Patients who developed pleural effusions were more likely to have achieved MR4.5 after 6 months of dasatinib than those without effusions (P = .008). Pulmonary hypertension occurred in 5% of patients, frequently in association with pleural effusion, and was reversible upon dasatinib cessation in 6 of 7 patients. Dose reductions and temporary cessations had minimal impact on MR rates. Our observations suggest that by using the lowest effective dose in older patients to minimize the effusion risk, dose modification for cytopenias, and care with concomitant antiplatelet therapy, the necessity for permanent dasatinib cessation due to toxicity is likely to be minimal in immunologically competent patients.

Current approach to the treatment of chronic myeloid leukaemia

Of all the cancers, chronic myeloid leukaemia (CML) has witnessed the most rapid evolution of the therapeutic milieu in recent decades. The introduction of tyrosine kinase inhibitors (TKIs) as a therapeutic option has profoundly changed patient experience and outcome. The availability of multiple new highly effective therapies has increasingly underscored the importance of a good understanding of the underlying pathophysiological basis in CML, as well as patient-specific factors in choosing the right treatment for every individual. The treatment of CML has migrated in many jurisdictions from the office of a highly specialized malignant hematologist to the general hematologist or even a general practitioner. The goal of this review is to offer an overview of the modern approach to the treatment of CML, with an emphasis on chronic phase (CP) CML, including both TKI-based therapies such as imatinib, dasatinib, nilotinib, bosutinib and ponatinib, and non-TKI medications, such as omacetaxine. We discuss evidence behind each drug, most common and material adverse reactions and outline how this information can be used in selecting the right drug for the right patient. We also discuss evidence as it relates to other therapies, including stem cell transplant (SCT), and patients in accelerated (AP) and blastic phase (BP).

Sequential Use of Second-Generation Tyrosine Kinase Inhibitor Treatment and Intensive Chemotherapy Induced Long-Term Complete Molecular Response in Imatinib-Resistant CML Patient Presenting as a Myeloid Blast Crisis

Myeloid blast crisis of chronic myeloid leukemia (CML-MBC) is rarely seen at presentation and has a poor prognosis. There is no standard therapy for CML-MBC. It is often difficult to distinguish CML-MBC from acute myeloid leukemia expressing the Philadelphia chromosome (Ph+ AML). We present a case in which CML-MBC was seen at the initial presentation in a 75-year-old male. He was treated with conventional AML-directed chemotherapy followed by imatinib mesylate monotherapy, which failed to induce response. However, he achieved long-term complete molecular response after combination therapy involving dasatinib, a second-generation tyrosine kinase inhibitor, and conventional chemotherapy.

Management of CML-blast crisis

Tyrosine kinase inhibitors (TKI) have moderately improved survival in BC, but a median survival of less than 1 year is still unsatisfactory. This article reviews the various tests required for diagnosis of BC, features at diagnosis, treatment modalities (intensive chemotherapy, TKI, allo-SCT and a selection of investigational agents), options of prevention and predictors of progression. The best prognosis is observed in patients that achieve a 2nd CP. Allo-SCT probably further improves prognosis of patients in 2nd CP. The choice of TKI should be directed by the mutation profile of the patient. BC can be prevented. A careful analysis of risk factors for progression may help. Current treatment options are combined in a concluding strategy for the management of BC.

Association of pleural effusion with an early molecular response in patients with newly diagnosed chronic-phase chronic myeloid leukemia receiving dasatinib: Results of a D-First study

Despite the efficacy and safety of dasatinib treatment for chronic-phase chronic myeloid leukemia (CML-CP), adverse effects such as pleural effusion (PE) are still a serious concern. We determined the clinical significance of PE incidence using patient data derived from the D-First clinical study. In the present study, chest radiography and quantification of specific lymphocyte subsets were performed routinely after initiation of dasatinib treatment. Among 52 patients with newly diagnosed CML-CP, 17 (33%) developed PE within 18 months after initial dasatinib administration, but all cases were moderate (Grade 1, 10 patients; Grade 2, 7 patients). CD56+ lymphocyte counts at 1 month correlated significantly with the incidence of PE, whereas lymphocytosis did not. The major molecular response (MMR) rate at 3 months (although not at later times) was significantly higher in PE-positive patients than PE-negative patients (59% versus 24%, respectively; P=0.013). Deep molecular response rates did not differ significantly between the PE groups at any time point during the observation period. Our results suggest that an immune-mediated mechanism involving natural killer cells underlies the development of PE in patients receiving dasatinib for 18 months. This mechanism likely promotes transient tumor regression in patients newly diagnosed with CML-CP.

[A survey on tyrosine kinase inhibitor treatment in patients with chronic myeloid leukemia in China: from patients'perspective]

OBJECTIVES

To assess tyrosine kinase inhibitor (TKI) treatment status in patients with chronic myeloid leukemia (CML) in China and analyze the response-associated factors.

METHODS

From May to November in 2014, anonymous questionnaires were distributed to adult CML patients who were receiving TKI treatment all over China.

RESULTS

1 038 questionnaires were collected, 949 questionnaires were evaluable. Of the 949 evaluable respondents, 549 (58%) were male with the median age of 41 years (range, 18 to 88 years). 623 (66%) respondents lived in an urban area and 449 (47%) had an education level ≥ a bachelor degree. 888 (94%) respondents were in the chronic phase at diagnosis, and 690 (78%) of them started TKI treatment within one year after diagnosis. 794 (84%) respondents were on imatinib, 768 (81%) on the branded. With a median TKI treatment duration of 3 years (range, <1 to 13 years), 708 of 834 (85%) evaluable respondents achieved Ph- negative (i.e. complete cytogenetic response, CCyR), and 497 of 859 (46% ) BCR- ABL negative (i.e. complete molecular response, CMR). Multivariate analyses showed that female (OR=1.8, 95% CI 1.1-2.8,P=0.019 andOR=1.5, 95% CI 1.1-2.0,P=0.015), TKI treatment duration >3 years (OR=4.1, 95% CI 2.6- 6.5,P<0.001 andOR=3.7, 95% CI 2.7- 5.1,P< 0.001) and imatinib taken (OR=2.1, 95% CI 1.2-3.7,P=0.007 andOR=3.3, 95% CI 2.1-5.1,P<0.001) were factors affecting achieving both CCyR and CMR. In addition, higher education level (OR=2.0, 95% CI 1.3- 3.1,P=0.003), starting TKI treatment <1 year (OR=2.4, 95% CI 1.5- 3.8,P<0.001) and branded drugs received (OR=2.4, 95% CI 1.4- 4.0,P=0.001) were factors affecting achieving a CCyR. In 884 respondents, 534 (62%) reported " heavy financial burden" as the biggest treatment impediment, only 152 (17%) reported " poor quality of life related to adverse effects of TKI".

CONCLUSIONS

The survey showed that majority of the Chinese CML patients received imatinib as a TKI therapy, and most of the patients achieved satisfied responses by TKI. Financial burden became the major obstacle during TKI treatment.

Treatment of chronic myelogenous leukemia as a paradigm for solid tumors: how targeted agents in newly diagnosed disease transformed outcomes

Although chronic myelogenous leukemia (CML) is rare, with approximately 5000 new cases in the United States annually, it may be the poster child for the future of oncology. Imatinib mesylate, a selective Bcr-Abl tyrosine kinase inhibitor (TKI), transformed the course of CML from a rapidly fatal disease (median survival, 3 to 6 years) to a functionally curable, indolent disease with an estimated median survival of more than 25 years. This transformation can be attributed to several key factors: the identification of a causal and actionable molecular aberration-BCR-ABL; the development of a potent and selective Bcr-Abl TKI-imatinib; and, importantly the application of imatinib in the earliest phase of CML. In contrast, imatinib, if used in CML blastic phase, improves median survival to only about 1 year. Similar to CML blastic phase, metastatic solid malignancies have undergone genetic evolution, and their molecular aberrations are complex. As a result, resistance is common and eradication is difficult. The key to the dramatic improvement in the survival of patients with CML involved using imatinib in newly diagnosed disease, before blastic transformation. We hypothesize that metastatic solid tumors are analogous to CML blastic phase, and that to achieve improvements in solid tumor outcomes similar to those seen in CML, application of targeted agents to newly diagnosed disease may be required to prevent disease transformation (i.e., metastases). Targeting driver mutations at the time of diagnosis may be critical to the goal of markedly changing the outlook for patients with cancer.

Management of advanced-phase chronic myeloid leukemia

The management of chronic myeloid leukemia (CML) in accelerated or blast phase (advanced phase) remains a significant challenge despite the introduction of very effective tyrosine kinase inhibitors (TKIs). The biology of advanced-phase CML is complex and engages several pathways that are not optimally targeted by TKIs. Allogeneic stem cell transplantation remains the only potentially curative therapy, but the effectiveness of this conventional approach is limited. New strategies are required to improve the outlook for these patients.

Dasatinib-induced pleural effusion: Chylothorax, an option to consider

Dasatinib is a drug for treatment of oncogene fusion protein BCR-ABL-positive chronic myeloid leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia resistant/intolerant to imatinib. Pleural effusion (PE) is a common adverse effect, and in this context, we present four cases seen due to this cause. One of them is a chylothorax. The PE grade is variable, and the physiopathology is not well established, although a block in T-lymphocyte function or inhibition of platelet-derived growth factor receptor-β is suggested being involved. The PE is generally a lymphocyte-predominant exudate, but can also present as chylothorax. Several factors have been associated with its appearance, particularly the administration in two daily doses. Low grade (1–2) PEs usually respond well to interrupt the treatment while those of higher grade may also require therapeutic thoracentesis and corticosteroids. There are currently no firm guidelines that establish when to resort to one form of treatment or another.

Human CD34(+) progenitor hematopoiesis in liquid culture for in vitro assessment of drug-induced myelotoxicity

Utilization of validated CFU-GM assays for myelotoxicity screening is hampered by its labor-intensive and low-throughput nature. Herein, we transformed the defined CFU-GM assay conditions and IC90 endpoint into a higher throughput format. Human CD34(+) hematopoietic progenitors were cultured in a 96-well plate for 14 days with the same cytokine (rhGM-CSF) used in the CFU-GM assay. Expansion and differentiation toward myeloid lineages were manifested by characteristic changes in nuclear and cytoplasmic morphology and by temporal expression patterns of CD34, CD11b and CD13 markers. Inhibition of CD34(+) cell myelopoiesis by 12 anticancer drugs known to induce myelotoxicity in the clinic was quantifiable using either general cytotoxicity endpoints (cell growth area or total nucleus count) or lineage specific readouts (count of cells expressing CD11b and/or CD13). The IC50 and IC90 values derived from the concentration-response curves of 14-day drug exposure in CD34(+) cell culture were highly correlated with those from the international validation study of the CFU-GM assay, demonstrating capability to assess general cytotoxicity, cell proliferation and myelopoiesis simultaneously. These results suggest that this human CD34(+) hematopoietic progenitor cell assay can be used as a direct replacement for the validated, low throughput CFU-GM assay, and could expand application of in vitro myelotoxicity testing.

Diagnosis and Treatment of Chronic Myeloid Leukemia in 2015

Few neoplastic diseases have undergone a transformation in a relatively short period like chronic myeloid leukemia (CML) has in the last few years. In 1960, CML was the first cancer in which a unique chromosomal abnormality was identified and a pathophysiologic correlation suggested. Landmark work followed, recognizing the underlying translocation between chromosomes 9 and 22 that gave rise to this abnormality and, shortly afterward, the specific genes involved and the pathophysiologic implications of this novel rearrangement. Fast forward a few years and this knowledge has given us the most remarkable example of a specific therapy that targets the dysregulated kinase activity represented by this molecular change. The broad use of tyrosine kinase inhibitors has resulted in an improvement in the overall survival to the point where the life expectancy of patients today is nearly equal to that of the general population. Still, there are challenges and unanswered questions that define the reasons why the progress still escapes many patients, and the details that separate patients from ultimate cure. In this article, we review our current understanding of CML in 2015, present recommendations for optimal management, and discuss the unanswered questions and what could be done to answer them in the near future.

Long-term efficacy and safety of bosutinib in patients with advanced leukemia following resistance/intolerance to imatinib and other tyrosine kinase inhibitors

Long-term efficacy and safety of bosutinib (≥4 years follow-up from last enrolled patient) were evaluated in an ongoing phase 1/2 study in the advanced leukemia cohort with prior treatment failure (accelerated-phase [AP, n = 79] chronic myeloid leukemia [CML], blast-phase [BP, n = 64] CML, acute lymphoblastic leukemia [ALL, n = 24]). Fourteen AP, 2 BP, and 1 ALL patient remained on bosutinib at 4 years (vs. 38, 8, 1 at 1 year); median (range) treatment durations: 10.2 (0.1-88.6), 2.8 (0.03-55.9), 0.97 (0.3-89.2) months. Among AP and BP patients, 57% and 28% newly attained or maintained baseline overall hematologic response (OHR); 40% and 37% attained/maintained major cytogenetic response (MCyR) by 4 years (most by 12 months). In responders at 1 versus 4 years, Kaplan-Meier (KM) probabilities of maintaining OHR were 78% versus 49% (AP) and 28% versus 19% (BP); KM probabilities of maintaining MCyR were 65% versus 49% (AP) and 21% versus 21% (BP). Most common AEs (AP, BP) were gastrointestinal (96%; 83%), primarily diarrhea (85%; 64%), which was typically low grade (maximum grade 1/2: 81%; 59%) and transient; no patient discontinued due to diarrhea. Serious AEs occurred in 44 (56%) AP and 37 (58%) BP patients, most commonly pneumonia (n = 9) for AP and pyrexia (n = 6) for BP; 11 and 13 died within 30 days of last dose (2 considered bosutinib-related [AP] per investigator). Responses were durable in ∼50% AP responders at 4 years (∼25% BP patients responded at year 1, suggesting possible bridge-to-transplant role in BP patients); toxicity was manageable.

Severe thrombocytopenia after dasatinib treatment in a patient with Philadelphia chromosome-positive chronic myeloid leukemia

Dasatinib, a second-generation tyrosine kinase inhibitor, is used for treating patients with Philadelphia chromosome (Ph) positive leukemia, especially for those who are resistant or intolerant to imatinib. The common adverse effects associated to its use include myelosuppression, nausea, diarrhea, and peripheral edema. This study reports a very rare case of a 60-year-old male who suffered from severe thrombocytopenia after dasatinib administration. The platelet count did not increase even after dasatinib had been discontinued for more than 6 months. Various means had been tried, but the count of platelet did not increase, and the result was not optimistic. This is the first report of so severe thrombocytopenia after dasatinib treatment, and the pathophysiology underlying this reaction remains unknown. We hope that this case will help remind clinicians to pay more attention to the side effect of thrombocytopenia caused by dasatinib in the future.