Clinical decisions for chronic myeloid leukemia in the imatinib era

The Diagnosis of Chronic Myeloid Leukemia with Deep Adversarial Learning

Chronic myeloid leukemia (CML) is a clonal proliferative disorder of granulocytic lineage, with morphologic evaluation as the first step for a definite diagnosis. This study developed a conditional generative adversarial network (cGAN)-based model, CMLcGAN, to segment megakaryocytes from myeloid cells in bone marrow biopsies. After segmentation, the statistical characteristics of two types of cells were extracted and compared between patients and controls. At the segmentation phase, the CMLcGAN was evaluated on 517 images (512 × 512) which achieved a mean pixel accuracy of 95.1%, a mean intersection over union of 71.2%, and a mean Dice coefficient of 81.8%. In addition, the CMLcGAN was compared with seven other available deep learning-based segmentation models and achieved a better segmentation performance. At the clinical validation phase, a series of seven-dimensional statistical features from various cells were extracted. Using the t-test, five-dimensional features were selected as the clinical prediction feature set. Finally, the model iterated 100 times using threefold cross-validation on whole slide images (58 CML cases and 31 healthy cases), and the final best AUC was 84.93%. In conclusion, a CMLcGAN model was established for multiclass segmentation of bone marrow cells that performed better than other deep learning-based segmentation models.

Myeloid Blast Crisis of Chronic Myeloid Leukemia Followed by Lineage Switch to B-Lymphoblastic Leukemia: A Case Report

Lineage switch is very rare in blastic crisis of chronic myeloid leukemia (CML-BC). Here, we report a case of CML-BC in which the blast lineage switched from myeloid to B-lymphoid. A 35-year-old male was initially admitted to our hospital because of abdominal distention for over a year and dizziness for one week. Prior to presentation at our hospital, he visited a local hospital because of abdominal distention where his white blood cell count and bone marrow (BM) smear indicated CML. Results from peripheral blood (PB) counts, bone marrow analysis, immunophenotyping by flow cytometry, and the detection of the Philadelphia chromosome were consistent with a diagnosis of myeloid blast crisis from CML. The patient received chemotherapy with imatinib for induction, which diminished the number of blasts. However, after three months, the blasts were increased in the PB and BM. The BM study and immunophenotyping by flow cytometry revealed B-lymphoblastic leukemia. In accordance with his first admission, a chromosome study revealed a karyotype of 46, XY, t(9; 22)(q34; q11) in all 20 cells analyzed, and B-lymphoblastic transformation from CML was diagnosed. Despite three months of treatment with DVCP (daunorubicin, vincristine, cyclophosphamide and prednisone) chemotherapy in combination with dasatinib, the patient did not achieve complete remission. The patient decided to stop treatment and was discharged from the hospital for financial reasons. This case implicates the Philadelphia chromosome with p210 BCR-ABL1 fusion proteins as a key molecule in CML-BC. Further research is needed to assess the frequency, treatment, and prognosis of CML-BC patients with lineage switch.

Cytokines in Cancer Immunotherapy

Cytokines that control the immune response were shown to have efficacy in preclinical murine cancer models. Interferon (IFN)-α is approved for treatment of hairy cell leukemia, and interleukin (IL)-2 for the treatment of advanced melanoma and metastatic renal cancer. In addition, IL-12, IL-15, IL-21, and granulocyte macrophage colony-stimulating factor (GM-CSF) have been evaluated in clinical trials. However, the cytokines as monotherapy have not fulfilled their early promise because cytokines administered parenterally do not achieve sufficient concentrations in the tumor, are often associated with severe toxicities, and induce humoral or cellular checkpoints. To circumvent these impediments, cytokines are being investigated clinically in combination therapy with checkpoint inhibitors, anticancer monoclonal antibodies to increase the antibody-dependent cellular cytotoxicity (ADCC) of these antibodies, antibody cytokine fusion proteins, and anti-CD40 to facilitate tumor-specific immune responses.

Improving Outcomes in Chronic Myeloid Leukemia Over Time in the Era of Tyrosine Kinase Inhibitors

Most patients with chronic myeloid leukemia (CML) receiving treatment with BCR-ABL1 tyrosine kinase inhibitors (TKIs) will achieve favorable responses. Moreover, TKI therapy enables patients to experience long-term survival, with survival rates similar to those of individuals without CML. This enhanced survival has resulted from the availability of multiple BCR-ABL1 TKIs with efficacy, not only in frontline treatment, but, importantly, also in second- and third-line treatment. We have reviewed the changes in long-term outcomes in the era of TKI therapy and how these changes have affected treatment practices. We discuss the development of imatinib, the first BCR-ABL1 TKI, followed by newer TKIs, including nilotinib, dasatinib, bosutinib, and ponatinib. We consider the key studies that led to their development as frontline or later-line therapies, their safety profiles, and their effect on improving patient outcomes. With these improved outcomes, the definition of an optimal response has become more stringent, and treatment monitoring strategies have changed. Second-line patient populations have evolved from those with resistance to, or intolerance of, imatinib to those with moderate responses to, or low-grade adverse events with, imatinib. Although all TKIs are associated with high survival rates, newer TKIs have been associated with lower disease progression rates and, importantly, deeper treatment responses and, potentially, a greater chance of future treatment-free remission. Finally, we consider the unmet needs of patients with CML, including the challenges remaining for those without optimal responses during TKI therapy and new therapies and strategies to identify such patients at diagnosis.

Monitoring of response to therapy with imatinib mesylate in Chronic Myeloid Leukemia in chronic phase (CML-CP)

BACKGROUND

The BCR-ABL tyrosine kinase is a well validated therapeutic target in Chronic Myeloid Leukemia (CML). Imatinib mesylate (IM), a tyrosine kinase inhibitor is highly effective in the treatment of chronic phase CML. BCR - ABL transcripts have been well established as a molecular marker to document response to therapy in CML. Periodic monitoring of this marker helps in evolving therapeutic strategies with IM and also in diagnosing early relapse. This study was undertaken to monitor therapeutic response to IM in CML in chronic phase (CML-CP) by assessing BCR-ABL by real time quantitative PCR (RQ-PCR) techniques and to determine the effectiveness of the Indian generic IM.

METHODS

One hundred consecutive patients of CML in chronic phase (CML-CP) were treated with an Indian generic of IM. Eighty-five patients were evaluable at 12 months of therapy. At entry, diagnosis of CML-CP was confirmed by FISH and RQ-PCR. Response to therapy was monitored by assessing BCR-ABL levels by RQ-PCR at 6 and 12 months of therapy. Regular follow up of patients was done to evaluate the safety profile of IM used in these patients.

RESULTS

Complete hematological response (CHR) rates at 3, 6, 9 and 12 months were 92%, 94%, 100% and 100% respectively. The total molecular response at 12 months was 43.52% of which complete molecular response (CMR) was noted in 17.64% and major molecular response (MMR) was observed in 25.88%. A cumulative survival probability of 0.8 was observed.

CONCLUSION

The Indian generic molecule of IM is effective in the treatment of CML-CP. The cost of Indian generic molecule is less than Rs. 10,000 per month there by making this affordable for large number of CML-CP patients in India.

An uneventful pregnancy and delivery, in a case with chronic myeloid leukemia on imatinib

The concomitant occurrence of pregnancy and chronic myelogenous leukemia is uncommon. We describe the successful management of a 24-year-old woman in the first trimester of her pregnancy with chronic myelogenous leukemia (CML) in the chronic phase, who was on treatment with imatinib, which was stopped by 10^th week of pregnancy. Until, she completed full term of pregnancy she was on hydroxyurea. The use of imatinib did not have adverse effects on the fetus. The patient had a normal vaginal delivery and gave birth to a healthy 2500 g girl at 37 weeks of gestation. We conclude that imatinib in the first trimester of pregnant lady with CML, though has particular concern regarding the potential teratogenic and other adverse effects, has shown evidences of safe conception, pregnancy and delivery in ladies with CML.

Selection of therapy: rational decisions based on molecular events

This article reviews to what extent molecular data can be used to rationalize therapeutic choices in the treatment of chronic myeloid leukemia. Two categories of data are discussed: markers that globally measure risk but do not provide a molecular rationale for therapy selection; and biomarkers with a causal link to a clinical phenotype, such as certain mutations of the BCR-ABL kinase domain. As therapy selection is still mainly based on clinical criteria, molecular biomarkers are discussed in the context of available clinical prognostication tools, focusing on biomarkers that do not reflect disease burden as a surrogate of responsiveness to treatment.

Hepatic veno-occlusive disease following stem cell transplantation: incidence, clinical course, and outcome

The occurrence of hepatic veno-occlusive disease (VOD) has been reported in up to 60% of patients following stem cell transplantation (SCT), with incidence varying widely between studies depending on the type of transplant, conditioning regimen, and criteria used to make the diagnosis. Severe VOD is characterized by high mortality and progression to multiorgan failure (MOF); however, there is no consensus on how to evaluate severity. This review and analysis of published reports attempts to clarify these issues by calculating the overall mean incidence of VOD and mortality from severe VOD, examining the effect of changes in SCT practice on the incidence of VOD over time, and discussing the methods used to evaluate severity. Across 135 studies performed between 1979 and October 2007, the overall mean incidence of VOD was 13.7% (95% confidence interval [CI]=13.3%-14.1%). The mean incidence of VOD was significantly lower between 1979-1994 than between 1994-2007 (11.5% [95% CI, 10.9%-12.1%] vs 14.6% [95% CI, 14.0%-15.2%]; P <.05). The mortality rate from severe VOD was 84.3% (95% CI, 79.6%-88.9%); most of these patients had MOF, which also was the most frequent cause of death. Thus, VOD is less common than early reports suggested, but the current incidence appears to be relatively stable despite recent advances in SCT, including the advent of reduced-intensity conditioning. The evolution of MOF in the setting of VOD after SCT can be considered a reliable indication of severity and a predictor of poor outcome.

Chronic myelogenous leukemia showing biphenotypic blast crisis followed by lineage switch to B lymphoblastic leukemia

Lineage switch is a very rare event in blastic crisis of chronic myelogenous leukemia (CML-BC). To our knowledge, only three cases of lineage switch between lymphoid and myeloid/myelomonocytic lineages have been reported in the literature. Here, we report a novel case of imatinib-resistant CML-BC, in which the blast lineage switched from biphenotypic to B-lymphoid.

(-)Gossypol and its combination with imatinib induce apoptosis in human chronic myeloid leukemic cells

Chronic myeloid leukemia (CML) is characterized by the presence of chimeric protein BCR-ABL associated with high tyrosine kinase (TK) activity, which leads to cell tumorogenicity, resistance to apoptosis, and differentiation. Gossypol is a natural polyphenolic compound isolated from cottonseed and has antiproliferative activity in a variety of cancer cell lines. (-)Gossypol is proved the potent component. Here we examined the growth inhibitory effect of (-)gossypol and its combination with imatinib in K562 cells. (-)Gossypol inhibited cell growth, promoted apoptosis, induced DeltaPsim loss, and cytochrome C release. Furthermore, (-)gossypol had a synergistic inhibitory effect on growth in K562 cells when combined with imatinib. Enhanced apoptosis, cytochrome C release, and caspase 3 cleavage as well as noticeable decrease of Mcl-1 and Bcl-XL were observed in K562 cells treated with both (-)gossypol and imatinib. These results suggest that (-)gossypol induced apoptosis in K562 cells through a mitochondria pathway and that the combination of imatinib and (-)gossypol might be an effective treatment for CML.

Clinical and prognostic significance of histamine monitoring in patients with CML during treatment with imatinib (STI571)

BACKGROUND

Although imatinib is highly effective in chronic myeloid leukemia (CML), drug-resistance may occur. Therefore, monitoring of minimal residual disease (MRD) during treatment with imatinib is important. However, most MRD-parameters are expensive and require special technology. We determined the value of histamine as MRD-marker in CML.

PATIENTS AND METHODS

Histamine levels were measured serially in whole blood samples before and during imatinib therapy in 80 CML patients by radioimmunoassay.

RESULTS

Histamine levels were highly upregulated in CML at diagnosis compared to healthy controls, and correlated with the presence of basophils. During treatment with imatinib, histamine levels decreased and returned to normal levels in those achieving a complete cytogenetic response (CCR). Loss of CCR during therapy was invariably accompanied by an increase in histamine. Moreover, a histamine level of >100 ng/ml three or six months after start of imatinib was associated with a significantly reduced probability of survival (p<0.05). Whereas basophils were found to correlate well with histamine during imatinib, no correlations were found between histamine and Ph+ metaphases or histamine and BCR/ABL.

CONCLUSION

Histamine-monitoring during treatment with imatinib is of prognostic significance.

Usefulness of quantitative assessment of JunB gene expression as a marker for monitoring chronic myeloid leukemia patients undergoing imatinib therapy

JunB is a component of the activator protein 1 transcription factors and has been identified to be important in hematopoiesis. Transgenic mice lacking JunB expression develop myeloproliferative disease resembling human chronic myeloid leukemia (CML). JunB expression was significantly decreased in CML patients. We used real-time quantitative reverse transcription-polymerase chain reaction analysis to monitor both JunB and BCR-ABL expression during imatinib therapy. Nineteen patients were evaluated every 2 to 4 weeks, and their levels of JunB expression before therapy were significantly decreased compared with those of healthy individuals. After imatinib therapy, an increase in JunB expression was found in 5 patients, all of whom achieved a complete cytogenetic response (CCR) and molecular response (MR), with a decrease in BCR-ABL expression. JunB expression decreased to a very low level in 2 patients, both of whom showed progression to blast crisis. Variable JunB expression was found in the other 12 patients, and their outcomes were mostly driven by BCR-ABL levels. The patients with an increase in JunB expression were statistically more likely to achieve a major cytogenetic response (P = .045), CCR (P = .033), and MR (P = .033) than the group with no increase in JunB expression, and a durable response was observed. This study revealed that an increase in JunB expression is a good prognostic marker for predicting clinical response in CML patients treated with imatinib when such data are combined with an evaluation of BCR-ABL expression.

Continuous complete hematological and cytogenetic remission with molecular minimal residual disease 9 years after discontinuation of interferon-alpha in a patient with Philadelphia chromosome-positive chronic myeloid leukemia

Interferon-alpha has been used as standard therapy for patients with Philadelphia-positive chronic myeloid leukemia (CML) for more than 20 years. Recently randomized trials have shown a superiority of the tyrosine kinase inhibitor imatinib in respect to its efficacy to induce complete hematological and cytogenetic remissions and more importantly in overall survival. Although follow-up is much shorter for imatinib than for interferon-alpha, this data changed the treatment algorithms in this disease. At the end of the era of interferon-alpha as a single-drug first-line treatment for most patients we present a case report which exemplifies a rare but exciting property of interferon-alpha in CML: the induction of complete hematological and cytogenetic remissions which can persist over years after discontinuation of the drug. Hence, the enrollment of CML patients in clinical trials which explore a combination treatment of imatinib and interferon-alpha is warranted.

Targeted treatment of hypereosinophilic syndromes and chronic eosinophilic leukemias with imatinib mesylate

Idiopathic hypereosinophilic syndrome (HES) and chronic eosinophilia leukemia (CEL) represent the most recent additions to the list of molecularly defined chronic myeloproliferative disorders. Beginning with the observation that imatinib mesylate (Gleevec) could elicit rapid and complete hematologic remissions in a proportion of patients with HES, a reverse bedside-to-bench translational research effort led to the discovery of FIP1L1-PDGFRA, a novel fusion gene on chromosome 4q12 whose product is an imatinib-sensitive protein tyrosine kinase. FIP1L1-PDGFRA is the first description of a gain-of-function fusion gene derived from an interstitial chromosomal deletion rather than a reciprocal translocation. Empiric use of imatinib in HES and CEL provides a dramatic example of how the development of targeted therapeutics can provide tremendous insight into the molecular etiology of what appear to be a diverse and otherwise indecipherable collection of diseases. In this review, we discuss the role of imatinib in HES/CEL and other malignancies characterized by constitutively activated tyrosine kinases, and examine molecular features of the FIP1L1-PDGFRA fusion.

Targeted treatment of hypereosinophilic syndromes and chronic eosinophilic leukemias with imatinib mesylate

Idiopathic hypereosinophilic syndrome (HES) and chronic eosinophilia leukemia (CEL) represent the most recent additions to the list of molecularly defined chronic myeloproliferative disorders. Beginning with the observation that imatinib mesylate (Gleevec) could elicit rapid and complete hematologic remissions in a proportion of patients with HES, a reverse bedside-to-bench translational research effort led to the discovery of FIP1L1-PDGFRA, a novel fusion gene on chromosome 4q12 whose product is an imatinib-sensitive protein tyrosine kinase. FIP1L1-PDGFRA is the first description of a gain-of-function fusion gene derived from an interstitial chromosomal deletion rather than a reciprocal translocation. Empiric use of imatinib in HES and CEL provides a dramatic example of how the development of targeted therapeutics can provide tremendous insight into the molecular etiology of what appear to be a diverse and otherwise indecipherable collection of diseases. In this review, we discuss the role of imatinib in HES/CEL and other malignancies characterized by constitutively activated tyrosine kinases, and examine molecular features of the FIP1L1-PDGFRA fusion.

Chronic myeloid leukemia—still a few questions

The study of chronic myeloid leukemia has yielded many insights, especially after the discovery of the Ph chromosome, into the pathogenesis of leukemia and other forms of malignant disease. Most recently, knowledge of the central function of the BCR-ABL fusion gene led to the development of a small molecule, imatinib, that has proved remarkably effective at reducing the number of leukemia cells in individual CML patients and promises to prolong life substantially in comparison with earlier treatments. However, many questions relating to this exciting new agent remain unanswered, for example, how exactly it works, how patients develop resistance and what can be done to prevent or delay its onset, and whether any patient can really be "cured" by its use.

Chronic myeloid leukemia

Chronic myeloid leukemia (CML) was the first human malignancy to be associated with a specific genetic lesion, the Philadelphia chromosome, harboring the BCR-ABL oncogene. Since then, it has become a paradigm for the discovery of molecular mechanisms and targeted therapeutic approaches in the field of hematologic neoplasias. The past 5 years or so have been particularly fruitful in the dissection of the signal transduction pathways abnormally activated in CML and in the translation of this knowledge to clinical practice. In this report, we discuss the biological basis for such translation and highlight the current and potential tools for the effective treatment of CML patients. The first part presents a review of the basic concepts on the biology of CML and their application to the design of targeted therapy. The mechanisms of action of the molecular-specific drugs currently used in clinical trials are discussed, with emphasis on the description of the most promising new compounds that are enhancing the potential for effective alternative or combination chemotherapy in CML. In the following section, we explain how molecular monitoring of response to imatinib mesylate in patients with CML can be used as a guide to clinical management. In particular, we discuss the relative value of regular quantitative RT/PCR and cytogenetic analyses, how responding patients should be monitored and managed, and how to investigate patients who are refractory or become resistant to imatinib treatment. In the last part of this report, a discussion on the possibility of managing CML with patient-specific strategies is presented. We review the current treatment options, highlight the factors impacting on decision making, discuss the range of possibilities for future therapeutic strategies and propose a systematic approach for individualizing treatment for patients in different disease categories.