Dose modification dynamics of ponatinib in patients with chronic-phase chronic myeloid leukemia (CP-CML) from the PACE and OPTIC trials

Ponatinib, the only approved all known-BCR::ABL1 inhibitor, is a third-generation tyrosine-kinase inhibitor (TKI) designed to inhibit BCR::ABL1 with or without any single resistance mutation, including T315I, and induced robust and durable responses at 45 mg/day in patients with CP-CML resistant to second-generation TKIs in the PACE trial. However, cardiovascular toxicities, including arterial occlusive events (AOEs), have emerged as treatment-related AEs within this class of TKIs. The OPTIC trial evaluated the efficacy and safety of ponatinib using a novel, response-based, dose-reduction strategy in patients with CP-CML whose disease is resistant to ≥2 TKIs or who harbor T315I. To assess the dose-response relationship and the effect on the safety of ponatinib, we examined the outcomes of patients with CP-CML enrolled in PACE and OPTIC who received 45 mg/day of ponatinib. A propensity score analysis was used to evaluate AOEs across both trials. Survival rates and median time to achieve ≤1% BCR::ABL1IS in OPTIC were similar or better than in PACE. The outcomes of patients with T315I mutations were robust in both trials. Patients in OPTIC had a lower exposure-adjusted incidence of AOEs compared with those in PACE. This analysis demonstrates that response-based dosing for ponatinib improves treatment tolerance and mitigates cardiovascular risk.

Clinical parameters and cardiovascular risk factors related to heart failure with preserved ejection fraction: a comparative analysis between HFA-PEFF and H2FPEF Scores

Background

Heart failure with preserved ejection fraction (HFpEF) diagnosis remains challenging, since several mechanisms (diastolic and systolic reserve abnormalities, chronotropic incompetence, ventricular or vascular stiffening, atrial dysfunction, pulmonary hypertension, impaired vasodilation, endothelial dysfunction, energetic abnormalities and autonomic dysfunction) play different roles in HFpEF development. European Society of Cardiology HF guidelines recently suggested a stepwise non-invasive diagnostic approach consisting of three steps: the first is clinical, the second includes echocardiographic and laboratory data (natriuretic peptides), named HFA-PEEF score, and finally, in case of inconclusive findings, diastolic stress echocardiography is recommended. On the other hand, in United States, another multiparametric score, named H2FPEF, has been proposed for HFpEF diagnosis, and including, in addition to echocardiographic parameters, also clinical data; thereby more applicable in the outpatient clinical arena.

Purpose

Whether there is a clinical overlap between the two scores (HFA-PEEF and H2FPEF) as well as whether the addition of clinical data to the HFA-PEEF could improve its ability to identify different HFpEF phenotypes is still an open issue and these were the aims of our study.

Methods

HFA-PEEF and H2FPEF scores were systematically applied on 1,156 consecutive subjects with preserved ejection fraction who undergone cardiovascular evaluation at the Cardiovascular Prevention Center of Fondazione Don Gnocchi & University of Parma. All subjects underwent cardiovascular risk assessment followed by echocardiography and cardiopulmonary exercise testing; due to the outpatient (non-acute) setting of the evaluation, natriuretic peptides assay was not performed. Clinical data and cardiovascular risk factors data were compared between different groups of HFpEF risk.

Results

According to H2FPEF score, low risk (<40%) of HFpEF was found in 659 (57%), moderate in 300 (26%) and high (>75%) in 197 (17%); according to HFA-PEEF score, 675 (58%) had 0 or 1 point, 253 (22%) had 2 points and 230 (20%) had 3 or 4 points (moderate-to-high risk). Patients with higher HFA-PEEF score were older (p<0.001), had higher prevalence of HTN (p<0.001), diabetes (p<0.001), obesity (p<0.001), sedentary lifestyle (p<0.001), AF (p<0.001) and CCS (p<0.001) (figure 1). More specifically, AF was associated to a 6.3-fold higher risk (p<0.001) of high (3–4) HFA-PEEF Score, age >75 years to a 4.6-fold higher risk, HTN to a 3.6-fold higher risk (p<0.001), CCS to a 3.3-fold higher risk (p<0.001), obesity to a 2.2-fold higher risk (p<0.001), diabetes to a 1.9-fold higher risk (p<0.001) and sedentary to a 1.7-fold higher risk (p=0.001).

Conclusions

Although HFA-PEEF score does not include clinical data, patients with older age, atrial fibrillation, hypertension, hypertensive heart, diabetes, sedentary lifestyle and chronic coronary syndrome show a higher ESC risk of HFpEF.

Funding Acknowledgement

Type of funding sources: None.

Cardiopulmonary response to exercise and heart failure with preserved ejection fraction risk: a comparative analysis of HFA-PEFF and H2FPEF scores

Background

Exercise intolerance evaluation in Heart failure with preserved ejection fraction (HFpEF) remains challenging, since several mechanisms (diastolic and systolic reserve abnormalities, low chronotropic reserve (CR), ventricular or vascular stiffening, atrial dysfunction, pulmonary hypertension, endothelial dysfunction, energetic abnormalities and autonomic dysfunction) play different roles. European Society of Cardiology HF guidelines recently suggested a stepwise non-invasive HFpEF diagnostic approach consisting of three steps: clinical, echocardiographic and laboratory data (natriuretic peptides), named HFA-PEEF Score, and finally, in case of inconclusive findings, diastolic stress echocardiography data. Cardiopulmonary exercise testing (CPET) may represent a promising further non-invasive diagnostic tool in HFpEF evaluation since allow to assess the presence of reduced functional capacity as well as to differentiate between cardiovascular, ventilatory or peripheral causes.

Purpose

Whether increased risk of HFpEF is associated with different and specific cardiopulmonary responses to exercise is still an open issue and this was the aim of our study.

Methods

1.156 consecutive subjects with preserved ejection fraction undergoing cardiovascular evaluation at the Cardiovascular Prevention Center of Fondazione Don Gnocchi & University of Parma were enrolled. All subjects underwent cardiovascular evaluation and echocardiography, HFA-PEEF and H2FPEF Score assessment and cardiopulmonary exercise testing. Different cardiopulmonary response to exercise were compared between different groups of HFpEF risk.

Results

According to HFA-PEEF Score, 675 (58%) had 0 or 1 point, 253 (22%) had 2 points and 230 (20%) had 3 or 4 points (moderate-to-high risk). Patients with both higher HFA-PEEF and H2FPEF Score showed lower functional capacity, expressed as low peak V02 (p<0.001) associated with lower oxygen pulse (V02/HR) (p<0.001), cardiac output (CO) at peak (p<0.001), CR (p<0.001), ventilatory efficiency (expressed as VE/VC02 slope) (p<0.001) and oxygen uptake extraction (OUES) (p<0.001). Moreover, higher H2FPEF Score patients showed lower stroke volume (SV) at peak (p<0.001), while high HFA-PEEF score was not associated to SV at peak (Table 1 and Figure 1). More specifically, the presence of reduced cardiovascular efficiency (V02/Watt Slope <7) was associated to a 2.2-fold higher risk of HFpEF (p=0.003), impaired ventilator efficiency (VE/VCO2 Slope >35) to a 2.4-fold higher risk (p<0.001), reduced CR (<70%) 4.3-fold higher risk (p<0.001).

Conclusions

Different degrees HFpEF risk, estimated using both HFA-PEEF and H2FPEF score, are associated with different cardiopulmonary responses to exercise. High HFpEF risk patients show low functional capacity, cardiovascular and ventilator efficiency due to lower cardiac output at peak, despite preserved ejection fraction, associated to lower chronotropic response to exercise.

Funding Acknowledgement

Type of funding sources: None.

A novel cell line panel reveals non-genetic mediators of platinum resistance and phenotypic diversity in high grade serous ovarian cancer

OBJECTIVES

Resistance to cancer therapy is an enduring challenge and accurate and reliable preclinical models are lacking. We interrogated this unmet need using high grade serous ovarian cancer (HGSC) as a disease model.

METHODS

We created five in vitro and two in vivo platinum-resistant HGSC models and characterised the entire cell panel via whole genome sequencing, RNASeq and creation of intraperitoneal models.

RESULTS

Mutational signature analysis indicated that platinum-resistant cell lines evolved from a pre-existing ancestral clone but a unifying mutational cause for drug resistance was not identified. However, cisplatin-resistant and carboplatin-resistant cells evolved recurrent changes in gene expression that significantly overlapped with independent samples obtained from multiple patients with relapsed HGSC. Gene Ontology Biological Pathways (GOBP) related to the tumour microenvironment, particularly the extracellular matrix, were repeatedly enriched in cisplatin-resistant cells, carboplatin-resistant cells and also in human resistant/refractory samples. The majority of significantly over-represented GOBP however, evolved uniquely in either cisplatin- or carboplatin-resistant cell lines resulting in diverse intraperitoneal behaviours that reflect different clinical manifestations of relapsed human HGSC.

CONCLUSIONS

Our clinically relevant and usable models reveal a key role for non-genetic factors in the evolution of chemotherapy resistance. Biological pathways relevant to the extracellular matrix were repeatedly expressed by resistant cancer cells in multiple settings. This suggests that recurrent gene expression changes provide a fitness advantage during platinum therapy and also that cancer cell-intrinsic mechanisms influence the tumour microenvironment during the evolution of drug resistance. Candidate genes and pathways identified here could reveal therapeutic opportunities in platinum-resistant HGSC.

P127 PERI–VASCULAR ADIPOSE TISSUE ATTENUATION ON CHEST COMPUTED TOMOGRAPHY IN PATIENTS WITH MARFAN SYNDROME: A CASE SERIES

Background and aim of the work

Marfan Syndrome is a genetic disorder that determines histopathological alterations of the aortic vascular wall leading to increased inflammatory component. The peri–vascular adipose tissue attenuation is a method able to capture localized vascular inflammation by mapping spatial changes of perivascular tissue attenuation on computed tomography.

Methods

We measured peri–vascular adipose tissue attenuation around the ascending aorta in three consecutive subjects with confirmed genetic diagnosis of Marfan Syndrome. All subjects received the genetic diagnosis of fibrillin–1 gene mutation as part of the family screening of patients with known Marfan Syndrome. Chest computed tomography was performed in such asymptomatic subjects after genetic confirmation of Marfan Syndrome. None of these subjects showed aortic aneurysms or suffered from chronic inflammatory/infectious disease.

Results

In the three subjects identified with Marfan Syndrome the value of aortic peri–vascular adipose tissue attenuation measured at chest computed tomography was higher than normal and the volume of aortic peri–vascular adipose tissue was lower.

Conclusion

These preliminary observations suggest that peri–vascular adipose tissue attenuation is unexpectedly high in patients with Marfan Syndrome, notwithstanding the normal aortic diameter at the time of computed tomography. Whether this observation may find a clinical use in suspected Marfan Syndrome or in predicting aortic complications in Marfan Syndrome is worth to be assessed in prospective studies.

P56 SPONTANEOUS CORONARY ARTERY DISSECTIONS: ANALYSIS OF NON TRADITIONAL RISK FACTORS

 

The etiology of spontaneous coronary dissection (SCAD) is not well defined and Non traditional risk factors (NT–RF) have assumed increasing interest, but few data are available. NT–RF include three categories: Sex–related (SR–NT–FR), Sex–predominant (SP–NT–RF) and Gender–related (GR–NT–RF). (Table 1)

Aim of the Study

The objective of our analysis was to evaluate the incidence of NT–RF in Parma SCAD registry population.

Material and methods

We reviewed 62 patients with SCAD enrolled between January 2013 through November 2021

Results

Traditional risk factors were less common: hypertension was the most prevalent (39 pts, 62.9%). When considering NT–RF, 51 patients (82%) had at least one of all, with at least one SR–RF (66%) or GR–RF (64,5%). Patients with NT–RF were younger at time of SCAD (mean age 53 vs 66; p = 0.027) and they were predominantly females (48 vs 7 pts, p = 0.004) (Table 2). No differences were found among NT–RF SCAD and nNT–RF SCAD patients by fibromuscular dysplasia, peripheral arterial disease and chronic kidney disease. Patients with SCAD more often presented with non ST–segment elevation myocardial infarction (43 pts, 72.6%) vs ST–segment elevation (17 pts, 27.4%). No differences in clinical presentation and angiographic characteristics were found among NT–RF and nNT–RF patients group. MACE occurred in 17.7% of patients of the overall study population, at a median follow–up of 23 (interquartile range: 11;57) months. When comparing the incidence of cardiovascular events in the 2 study groups there was a trend toward a higher prevalence of MACE in NT–RF group without statistical significance (NT–RF SCAD 19.6% – nNT–RF SCAD 9.1%; p = 0.4). (Table 3)

Conclusion

SCAD is an emerging cause of myocardial infarction in young and middle–aged women without the traditional cardiovascular risk profile. Although overall survival seems good, SCAD is a potentially malignant disease which can present with ventricular arrhythmias and sudden cardiac death. Risk estimation is difficult in women, due to the scarce validity of prediction models, therefore a great effort must be made by the clinical community for the widespread diffusion and use of models incorporating NT–RF. Acknowledgement of peculiar features of this disease could help clinicians and researchers to establish targeted interventions for cardiovascular primary prevention, early diagnosis and secondary prevention in women, including rehabilitation and stress management programmes.

Retrospective analysis of arterial occlusive events in the PACE trial by an independent adjudication committee

Background

The phase 2 PACE (Ponatinib Ph+ ALL and CML Evaluation) trial of ponatinib showed robust long-term benefit in relapsed Philadelphia chromosome-positive (Ph+) leukemia; arterial occlusive events (AOEs) occurred in ≥ 25% of patients based on investigator reporting. However, AOE rates vary depending on the definitions and reporting approach used.

Methods

To better understand clinically relevant AOEs with ponatinib, an independent cardiovascular adjudication committee reviewed 5-year AOE data from the PACE trial according to a charter-defined process and standardized event definitions.

Results

A total of 449 patients with chronic myeloid leukemia (CML) or Ph+ acute lymphoblastic leukemia (ALL) received ponatinib (median age 59 y; 47% female; 93% ≥ 2 prior tyrosine kinase inhibitors (TKIs); median follow-up, 37.3 months). The adjudicated AOE rate (17%) was lower than the non-adjudicated rate (i.e., rate before adjudication; 25%). The only adjudicated AOE in > 2% of patients was peripheral arterial occlusive disease (4%). Exposure-adjusted incidence of newly occurring adjudicated AOEs decreased over time. Patients with multiple baseline cardiovascular risk factors had higher adjudicated AOE rates than those without risk factors.

Conclusions

This independent adjudication study identified lower AOE rates than previously reported, suggesting earlier overestimation that may inaccurately reflect AOE risk with ponatinib. This trial was registered under ClinicalTrials.gov identifier NCT01207440 on September 23, 2010 (https://clinicaltrials.gov/ct2/show/NCT01207440).

Immune checkpoint inhibitor treatment of a first cancer is associated with a decreased incidence of second primary cancer

Background

Second primary cancers (SPCs) are diagnosed in over 5% of patients after a first primary cancer (FPC). We explore here the impact of immune checkpoint inhibitors (ICIs) given for an FPC on the risk of SPC in different age groups, cancer types and treatments.

Patients and methods

The files of the 46 829 patients diagnosed with an FPC in the Centre Léon Bérard from 2013 to 2018 were analyzed. Structured data were extracted and electronic patient records were screened using a natural language processing tool, with validation using manual screening of 2818 files of patients. Univariate and multivariate analyses of the incidence of SPC according to patient characteristics and treatment were conducted.

Results

Among the 46 829 patients, 1830 (3.9%) had a diagnosis of SPC with a median interval of 11.1 months (range 0-78 months); 18 128 (38.7%) received cytotoxic chemotherapy (CC) and 1163 (2.5%) received ICIs for the treatment of the FPC in this period. SPCs were observed in 7/1163 (0.6%) patients who had received ICIs for their FPC versus 437/16 997 (2.6%) patients receiving CC and no ICIs for the FPC versus 1386/28 669 (4.8%) for patients receiving neither CC nor ICIs for the FPC. This reduction was observed at all ages and for all histotypes analyzed. Treatment with ICIs and/or CC for the FPC are associated with a reduced risk of SPC in multivariate analysis.

Conclusion

Immunotherapy with ICIs alone and in combination with CC was found to be associated with a reduced incidence of SPC for all ages and cancer types.

•

From 2013 to 2018, 3.9% of the 46 829 patients diagnosed with a first cancer presented with an SPC.

•

Treatment of the first cancer with ICIs was associated with a major reduction of SPC.

•

CC given for an FPC was also associated with a lower magnitude of reduction of SPC.

•

There were no SPC in cancer patients treated with ICIs in the localized phase of their first cancer.

European LeukemiaNet 2020 recommendations for treating chronic myeloid leukemia

The therapeutic landscape of chronic myeloid leukemia (CML) has profoundly changed over the past 7 years. Most patients with chronic phase (CP) now have a normal life expectancy. Another goal is achieving a stable deep molecular response (DMR) and discontinuing medication for treatment-free remission (TFR). The European LeukemiaNet convened an expert panel to critically evaluate and update the evidence to achieve these goals since its previous recommendations. First-line treatment is a tyrosine kinase inhibitor (TKI; imatinib brand or generic, dasatinib, nilotinib, and bosutinib are available first-line). Generic imatinib is the cost-effective initial treatment in CP. Various contraindications and side-effects of all TKIs should be considered. Patient risk status at diagnosis should be assessed with the new EUTOS long-term survival (ELTS)-score. Monitoring of response should be done by quantitative polymerase chain reaction whenever possible. A change of treatment is recommended when intolerance cannot be ameliorated or when molecular milestones are not reached. Greater than 10% BCR-ABL1 at 3 months indicates treatment failure when confirmed. Allogeneic transplantation continues to be a therapeutic option particularly for advanced phase CML. TKI treatment should be withheld during pregnancy. Treatment discontinuation may be considered in patients with durable DMR with the goal of achieving TFR.

Killer immunoglobulin-like receptor genotypes and chronic myeloid leukemia outcomes after imatinib cessation for treatment-free remission

Background

Natural Killer (NK) cells are innate lymphoid cells that can be cytotoxic toward a large panel of solid tumors and hematological malignancies including chronic myeloid leukemia (CML). Such a cytotoxicity depends on various receptors. Killer immunoglobulin‐like receptors (KIR) belong to these receptors and are involved in maturation process, then in the activation abilities of NK cells. Methods: We investigated the prognostic impact of the KIR2DL5B genotype in 240 CML patients included in two clinical trials investigating tyrosine kinase inhibitors (TKI) discontinuation: STIM and STIM2. Results: After adjustment for standard risk factors in CML, we found that the inhibitory receptor KIR2DL5B‐positive genotype was independently related to a delayed second deep molecular remission (HR 0.54, 95% CI [0.32‐0.91], P = 0.02) after TKI rechallenge but not to time to first deep molecular remission or treatment‐free remission rates. Conclusion: These results suggest that KIR2DL5B could carry a role in lymphocyte‐mediated control of leukemic residual disease control in patient with CML relapse.

Natural killer-cell counts are associated with molecular relapse-free survival after imatinib discontinuation in chronic myeloid leukemia: the IMMUNOSTIM study

Despite persistence of leukemic stem cells, patients with chronic myeloid leukemia who achieve and maintain deep molecular responses may successfully stop the tyrosine kinase inhibitor imatinib. However, questions remain unanswered regarding the biological basis of molecular relapse after imatinib cessation. In IMMUNOSTIM, we monitored 51 patients from the French Stop IMatinib trial for peripheral blood T cells and natural killer cells. Molecular relapse-free survival at 24 months was 45.1% (95% CI: 31.44%–58.75%). At the time of imatinib discontinuation, non-relapsing patients had significantly higher numbers of natural killer cells of the cytotoxic CD56^dim subset than had relapsing patients, while CD56^bright natural killer cells, T cells and their subsets did not differ significantly. Furthermore, the CD56^dim natural killer-cell count was an independent prognostic factor of molecular-relapse free survival in a multivariate analysis. However, expression of natural killer-cell activating receptors, BCR-ABL1⁺ leukemia cell line K562-specific degranulation and cytokine-induced interferon-gamma secretion were decreased in non-relapsing and relapsing patients as compared with healthy individuals. After imatinib cessation, the natural killer-cell count increased significantly and stayed higher in non-relapsing patients than in relapsing patients, while receptor expression and functional properties remained unchanged. Altogether, our results suggest that natural killer cells may play a role in controlling leukemia-initiating cells at the origin of relapse after imatinib cessation, provided that these cells are numerous enough to compensate for their functional defects. Further research will decipher mechanisms underlying functional differences between natural killer cells from patients and healthy individuals and evaluate the potential interest of immunostimulatory approaches in tyrosine kinase inhibitor discontinuation strategies. (ClinicalTrial.gov Identifier NCT00478985)

Long-Term Follow-Up of the French Stop Imatinib (STIM1) Study in Patients With Chronic Myeloid Leukemia

Purpose Imatinib (IM) can safely be discontinued in patients with chronic myeloid leukemia (CML) who have had undetectable minimal residual disease (UMRD) for at least 2 years. We report the final results of the Stop Imatinib (STIM1) study with a long follow-up. Patients and Methods IM was prospectively discontinued in 100 patients with CML with UMRD sustained for at least 2 years. Molecular recurrence (MR) was defined as positivity of BCR-ABL transcript in a quantitative reverse transcriptase polymerase chain reaction assay confirmed by a second analysis point that indicated an increase of one log in relation to the first analysis point at two successive assessments or loss of major molecular response at one point. Results The median molecular follow-up after treatment discontinuation was 77 months (range, 9 to 95 months). Sixty-one patients lost UMRD after a median of 2.5 months (range, 1 to 22 months), and one patient died with UMRD at 10 months. Molecular recurrence-free survival was 43% (95% CI, 33% to 52%) at 6 months and 38% (95% CI, 29% to 47%) at 60 months. Treatment was restarted in 57 of 61 patients with MR, and 55 patients achieved a second UMRD with a median time of 4 months (range, 1 to 16 months). None of the patients experienced a CML progression. Analyses of the characteristics of the study population identified that the Sokal risk score and duration of IM treatment were significantly associated with the probability of MR. Conclusion With a median follow-up of more than 6 years after treatment discontinuation, the STIM1 study demonstrates that IM can safely be discontinued in patients with a sustained deep molecular response with no late MR.

Treatment patterns and comparative effectiveness in elderly acute myeloid leukemia patients (age 70 years or older): the Lyon-university hospital experience

The treatment of very elderly patients (≥70 years) with acute myeloid leukemia remains controversial. We present here 302 patients seen over a 14-year period in order to understand the real-world treatment patterns and outcomes in this patient population. Less than 25% of patients achieved a complete remission. The median overall survival was 12.4, 11.5 and 2.6 months, with a 3-year rates of 27%, 17% and 6%, for non-acute promyelocytic leukemia patients receiving intensive chemotherapy, lower-intensity therapy or best supportive care (BSC), respectively. In all ages, results were not significantly different among patients receiving low-intensity therapy and intensive chemotherapy, but significantly worse in those treated with BSC only. Similarly, intensive chemotherapy and low-intensity therapy gave better survival rates than BSC in patients with favorable- or intermediate-risk cytogenetics and in those with unfavorable cytogenetics (p < 0.0001 and p = 0.04, respectively).

Oncogene- and drug resistance-associated alternative exon usage in acute myeloid leukemia (AML)

In addition to spliceosome gene mutations, oncogene expression and drug resistance in AML might influence exon expression. We performed exon-array analysis and exon-specific PCR (ESPCR) to identify specific landscapes of exon expression that are associated with DEK and WT1 oncogene expression and the resistance of AML cells to AraC, doxorubicin or azacitidine. Data were obtained for these five conditions through exon-array analysis of 17 cell lines and 24 patient samples and were extended through qESPCR of samples from 152 additional AML cases. More than 70% of AEUs identified by exon-array were technically validated through ESPCR. In vitro, 1,130 to 5,868 exon events distinguished the 5 conditions from their respective controls while in vivo 6,560 and 9,378 events distinguished chemosensitive and chemoresistant AML, respectively, from normal bone marrow. Whatever the cause of this effect, 30 to 80% of mis-spliced mRNAs involved genes unmodified at the whole transcriptional level. These AEUs unmasked new functional pathways that are distinct from those generated by transcriptional deregulation. These results also identified new putative pathways that could help increase the understanding of the effects mediated by DEK or WT1, which may allow the targeting of these pathways to prevent resistance of AML cells to chemotherapeutic agents.

Major molecular response achievement in CML Patients can be predicted by BCR-ABL1/ABL1 or BCR-ABL1/GUS ratio at an earlier time point of follow-up than currently recommended

Recent studies demonstrate that early molecular response to tyrosine-kinase inhibitors is strongly predictive of outcome in chronic myeloid leukemia patients and that early response landmarks may identify patients at higher risk for transformation who would benefit from an early switch to second-line therapy. In this study, we evaluated the ability of the control gene GUS to identify relevant thresholds for known therapeutic decision levels (BCR-ABL1/ABL1^IS  = 10% and 0.1%). We then defined the most relevant cut-offs for early molecular response markers (transcript level at 3 months, halving time and log reduction between diagnosis and 3 months of treatment) using GUS or ABL1. We demonstrated that, although both control genes could be used (in an equivalent way) to accurately assess early molecular response, the BCR-ABL1/GUS level at diagnosis is impacted by the higher GUS copy number over-expressed in CML cells, thus negatively impacting its ability to completely replace ABL1 at diagnosis. Furthermore, we pointed out, for the first time, that it would be helpful to monitor BCR-ABL1 levels at an earlier time point than that currently performed, in order to assess response to first-line tyrosine-kinase inhibitors and consider a potential switch of therapy as early as possible. We evaluated this optimal time point as being 19 days after the start of treatment in our cohort.

Leukocyte telomere length in mastocytosis: correlations with depression and perceived stress

BACKGROUND

Mastocytosisis a rare disease associated with chronic symptoms related to mast cell mediator release. Patients with mastocytosis display high level of negative emotionality such as depression and stress sensibility. Brain mast cells are mainly localized in the diencephalon, which is linked to emotion regulatory systems. Negative emotionality has been shown to be associated with telomere shortening. Taken together these observations led us to hypothesize that mast cells activity could be involved in both negative emotionality and telomere shortening in mastocytosis.

OBJECTIVE

To demonstrate a possible relationship between negative emotionality in mastocytosis and leukocytes telomere length.

METHODS

Leukocyte telomere length and telomerase activity were measured among mastocytosis patients and were correlated with perceived stress and depression assessed by the Beck Depression Inventory revised and the Perceived Stress Scale.

RESULTS

Mild-severe depression scores were frequent (78.9%) as well as high perceived stress (42.11%). Telomere length was correlated to perceived stress (r=0.77; p=0.0001) but not to depression in our population. Patients displaying Wild-type KIT significantly presented higher perceived stress levels. Patients with the D816VC KIT mutation who had high perceived stress scores displayed significantly shorter telomere but not if they had high depression scores.

CONCLUSION

These findings suggest that high perceived stress in mastocytosis could accelerate the rate of leukocytes telomere shortening. Since mastocytosis is, by definition, a mast cell mediated disease; these cells could be involved in this phenomenon. Mechanistic causal relationships between these parameters need to be investigated.

Chromatin redistribution of the DEK oncoprotein represses hTERT transcription in leukemias

Although numerous factors have been found to modulate hTERT transcription, the mechanism of its repression in certain leukemias remains unknown. We show here that DEK represses hTERT transcription through its enrichment on the hTERT promoter in cells from chronic and acute myeloid leukemias, chronic lymphocytic leukemia, but not acute lymphocytic leukemias where hTERT is overexpressed. We isolated DEK from the hTERT promoter incubated with nuclear extracts derived from fresh acute myelogenous leukemia (AML) cells and from cells expressing Tax, an hTERT repressor encoded by the human T cell leukemia virus type 1. In addition to the recruitment of DEK, the displacement of two potent known hTERT transactivators from the hTERT promoter characterized both AML cells and Tax-expressing cells. Reporter and chromatin immunoprecipitation assays permitted to map the region that supports the repressive effect of DEK on hTERT transcription, which was proportionate to the level of DEK-promoter association but not with the level of DEK expression. Besides hTERT repression, this context of chromatin redistribution of DEK was found to govern about 40% of overall transcriptional modifications, including those of cancer-prone genes. In conclusion, DEK emerges as an hTERT repressor shared by various leukemia subtypes and seems involved in the deregulation of numerous genes associated with leukemogenesis.

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

Data from registries suggest that the median age of chronic myelogenous leukemia (CML) patients is 10-15 years older than that of clinical trials. We conducted a prospective phase II study to evaluate imatinib mesylate (IM, 400 mg daily) in newly diagnosed chronic phase CML (CP-CML) patients. Patients aged 70 years and over diagnosed with CP-CML within 12 months were eligible. Thirty patients were enrolled from April 2002 to October 2004. Median age was 74.8 years (range, 70-90). Male/female ratio was 1.72. At inclusion, comorbidities were reported in all but one patient, Cumulative Illness Rating Scale for Geriatrics comorbidity mean index was 1.47, and 66% of patients had cardiovascular disease. The median daily IM dose was 392 mg (range, 256-445). IM was interrupted in patients with severe comorbidities. Treatment discontinuation was observed in 36.6% of patients. Cumulative incidence of complete cytogenetic response was 71.4 and 78.5% at 12 and 24 months, respectively. A high level of sustained responses was observed in patients with mild or moderate comorbidities. Seven-year estimated overall survival was 80.8% (95% CI: 59.0-91.7). Two-thirds of the patients were still on long-term therapy at cut-off, and no patients had died from progression. This trial was registered at http://www.clinicaltrials.gov as # NCT00219765.

Myeloma cells inhibit non-canonical wnt co-receptor ror2 expression in human bone marrow osteoprogenitor cells: effect of wnt5a/ror2 pathway activation on the osteogenic differentiation impairment induced by myeloma cells

Multiple myeloma (MM) is characterized by the impaired osteogenic differentiation of human mesenchymal stromal cells (hMSCs). Canonical Wnt signaling is critical for the regulation of bone formation, however, recent evidence suggests that the non-canonical Wnt agonist Wnt5a stimulates human osteoblastogenesis through its co-receptor Ror2. The effects of MM cells on non-canonical Wnt signaling and the effect of the activation of this pathway on MM-induced osteoblast exhaustion are not known and were investigated in this study. We found that the osteogenic differentiation of bone marrow hMSCs toward osteoprogenitor cells (PreOB) significantly increased Ror2 expression, and that MM cells inhibit Ror2 expression by PreOB in co-culture by inhibiting the non-canonical Wnt5a signaling. The activation of the non-canonical Wnt pathway in hMSCs by means of Wnt5a treatment and the overexpression of Wnt5 or Ror2 by lentiviral vectors increased the osteogenic differentiation of hMSCs and blunted the inhibitory effect of MM in co-culture. Consistently, Wnt5a inhibition by specific small interfering RNA reduced the hMSC expression of osteogenic markers. Our findings demonstrate that the Wnt5a/Ror2 pathway is involved in the pathophysiology of MM-induced bone disease and that the activation of the non-canonical Wnt5a/Ror2 pathway in hMSCs increases osteogenic differentiation and may counterbalance the inhibitory effect of MM cells.