Antonella Gozzini

Philadelphia-positive patients who already harbor imatinib-resistant Bcr-Abl kinase domain mutations have a higher likelihood of developing additional mutations associated with resistance to second- or third-line tyrosine kinase inhibitors.

Dasatinib and nilotinib are tyrosine kinase inhibitors (TKIs) developed to overcome imatinib resistance in Philadelphia-positive leukemias. To assess how Bcr-Abl kinase domain mutation status evolves during sequential therapy with these TKIs and which mutations may further develop and impair their efficacy, we monitored the mutation status of 95 imatinib-resistant patients before and during treatment with dasatinib and/or nilotinib as second or third TKI. We found that 83% of cases of relapse after an initial response are associated with emergence of newly acquired mutations. However, the spectra of mutants conferring resistance to dasatinib or nilotinib are small and nonoverlapping, except for T315I. Patients already harboring mutations had higher likelihood of relapse associated with development of further mutations compared with patients who did not harbor mutations (23 of 51 vs 8 of 44, respectively, for patients who relapsed on second TKI; 13 of 20 vs 1 of 6, respectively, for patients who relapsed on third TKI).

Azacitidine for the treatment of lower risk myelodysplastic syndromes : a retrospective study of 74 patients enrolled in an Italian named patient program.

Azacitidine induces responses and prolongs overall survival compared with conventional care regimens in patients who have high‐risk myelodysplastic syndromes (MDS). However, limited data are available concerning the efficacy and safety of azacitidine in patients who have lower risk MDS.

Age and dPCR can predict relapse in CML patients who discontinued imatinib: The ISAV study

Imatinib is effective for the treatment of chronic myeloid leukemia (CML). However even undetectable BCR‐ABL1 by Q‐RT‐PCR does not equate to eradication of the disease. Digital‐PCR (dPCR), able to detect 1 BCR‐ABL1 positive cell out of 107, has been recently developed. The ISAV study is a multicentre trial aimed at validating dPCR to predict relapses after imatinib discontinuation in CML patients with undetectable Q‐RT‐PCR. CML patients under imatinib therapy since more than 2 years and with undetectable PCR for at least 18 months were eligible. Patients were monitored by standard Q‐RT‐PCR for 36 months. Patients losing molecular remission (two consecutive positive Q‐RT‐PCR with at least 1 BCR‐ABL1/ABL1 value above 0.1%) resumed imatinib. The study enrolled 112 patients, with a median follow‐up of 21.6 months. Fifty‐two of the 108 evaluable patients (48.1%), relapsed; 73.1% relapsed in the first 9 months but 14 late relapses were observed between 10 and 22 months. Among the 56 not‐relapsed patients, 40 (37.0% of total) regained Q‐RT‐PCR positivity but never lost MMR. dPCR results showed a significant negative predictive value ratio of 1.115 [95% CI: 1.013–1.227]. An inverse relationship between patients age and risk of relapse was evident: 95% of patients <45 years relapsed versus 42% in the class ≥45 to <65 years and 33% of patients ≥65 years [P(χ2) < 0.0001]. Relapse rates ranged between 100% (<45 years, dPCR+) and 36% (>45 years, dPCR‐). Imatinib can be safely discontinued in the setting of continued PCR negativity; age and dPCR results can predict relapse. Am. J. Hematol. 90:910–914, 2015.

Selective anti-leukaemic activity of low-dose histone deacetylase inhibitor ITF2357 on AML1/ETO-positive cells.

We analysed the in vitro effects of a new hydroxamate derivative, ITF2357, on AML cells. ITF2357 potently induced histone acetylation. ITF2357 0.1 μM blocked proliferation and induced apoptosis in AML1/ETO-positive Kasumi-1 cells, while AML1/ETO-negative HL60, THP1 and NB4 cell lines were sensitive only to 1 μM ITF2357. Apoptosis was induced by 0.1 μM ITF2357 in AML1/ETO-positive primary blasts and U937-A/E cells induced to express AML1/ETO, but not in U937-A/E cells non-expressing AML1/ETO. In Kasumi-1 cells 0.1 μM ITF2357 induced AML1/ETO degradation through a caspase-dependent mechanism. ITF2357 0.1 μM also determined DNMT1 efflux from, and p300 influx to, the nucleus. Moreover, 0.1 μM ITF2357 determined local H4 acetylation and release of DNMT1, HDAC1 and AML1/ETO, paralleled by recruitment of p300 to the IL-3 gene promoter. ITF2357 treatment, however, did not induce re-expression of IL-3 gene. Accordingly, the methylation level of IL-3 promoter, as well as of several other genes, was unmodified. In conclusion, ITF2357 emerged as an anti-leukaemic agent very potent on AML cells, and on AML1/ETO-positive cells in particular. More relevantly, clearly emerged from our results that ITF2357 could be an ideal agent to treat AML subtypes presenting AML1/ETO fusion protein which determine HDAC involvement in leukaemogenesis.

Charlson comorbidity index and adult comorbidity evaluation-27 scores might predict treatment compliance and development of pleural effusions in elderly patients with chronic myeloid leukemia treated with second-line dasatinib

Background Comorbidities may affect survival and choice of treatment among cancer patients. In fact, comorbidities have been identified as significant determinants of response to therapy in older patients with acute myeloid leukemia, breast cancer, head and neck cancer, and lung cancer. The Charlson comorbidity index and adult comorbidity evaluation-27 are lists of comorbidities with a weight assigned from 1 to 6 for the former and from 0 to 3 for the latter score, derived from relative risk estimates of a proportional hazard regression model using clinical data. Design and Methods We retrospectively evaluated the Charlson index and adult comorbidity evaluation-27 score in a cohort of 125 elderly (> 60 years) patients with chronic phase chronic myeloid leukemia who received dasatinib after showing resistance or intolerance to imatinib with the aim of establishing associations between comorbidities and the development of pleural effusions or compliance with the drug treatment. Results We found a significant association between the Charlson index as well as the adult comorbidity evaluation-27 score and the rate of drug reduction or suspension: with regards to the Charlson index, 49% of score 0 patients had a dose reduction compared to 63% of patients with score 1, 74% of those with score 2 and 100% of patients with score 3–5 (P=0.03); with regards to the adult comorbidity evaluation-27 score, 45% of patients had score 0–1 and 69% of patients with score 2–3 had a dose reduction. Of the 65 patients with Charlson score 0, 29% had at least one suspension of treatment (79% for hematologic and 21% for non-hematologic toxicity), compared to 46% of patients with score 1 (37% for hematologic and 69% for non-hematologic toxicity), 58% of patients with score 2 (36% for hematologic and 64% for non-hematologic toxicity) and 100% of patients with score 3 or 4 (all patients for both types of toxicity). High adult comorbidity index-27 scores identified patients at high risk of grade 3/4 hematologic toxicity. Forty-one patients (32.8%) experienced pleural effusion during treatment: the highest scores for both indices were associated with an increased risk of pleural effusions. Conclusions In elderly patients with chronic myeloid leukemia treated with dasatinib, the rate of drug reduction or suspension and the incidence of pleural effusions seem to be associated with the presence of comorbidities: stratification according to the Charlson index and adult comorbidity evaluation-27 score before dasatinib therapy may enable the identification of patients at risk of major toxicities.

Incidence, risk factors and management of pleural effusions during dasatinib treatment in unselected elderly patients with chronic myelogenous leukaemia

To assess the most important features and clinical impact of pleural effusions, which are a common toxicity during dasatinib treatment and often impair its high efficacy, 172 unselected consecutive patients with chronic myelogenous leukaemia in chronic phase treated in 27 Italian centres, with dasatinib when aged >60 years for resistance/intolerance to imatinib, were examined. During treatment, 52/172 patients (30.2%) presented pleural effusion, which was grades 1–2 in 38 patients and grades 3–4 in 14 patients (8.1% of the entire cohort of patients), according to the WHO scale; in 14/52 patients (26.9%), there was a concomitant pericardial effusion. Pleural effusion was recurrent in 25/52 patients (48.0%). Median time from dasatinib to first pleural effusion was 11.0 months (interquartile range 3.6–18.6). Eleven patients (6.4%) required permanent dasatinib discontinuation. Only presence of concomitant pulmonary disease ( p = 0.035) and initial daily dose of dasatinib (140 mg vs 100 mg, p = 0.014) were significantly associated with pleural effusions. There were no differences among patients with or without pleural effusions as concerns response rates and overall survival. Pleural effusions were common in our unselected ‘real‐life’ population of elderly patients but were clinically manageable and did not seem to affect treatment results. Copyright

Severe hypoxia defines heterogeneity and selects highly immature progenitors within clonal erythroleukemia cells

We showed that resistance to severe hypoxia defines hierarchical levels within normal hematopoietic populations and that hypoxia modulates the balance between generation of progenitors and maintenance of hematopoietic stem cells (HSC) in favor of the latter. This study deals with the effects of hypoxia (0.1% oxygen) in vitro on Friends murine erythroleukemia (MEL) cells, addressing the question of whether a clonal leukemia cell population comprise functionally different cell subsets characterized by different hypoxia resistance. To identify leukemia stem cells (LSC), we used the Culture Repopulating Ability (CRA) assay we developed to quantify in vitro stem cells capable of short‐term reconstitution (STR). Hypoxia strongly inhibited the overall growth of MEL cell population, which, despite its clonality, comprised progenitors characterized by markedly different hypoxia‐resistance. These included hypoxia‐sensitive colony‐forming cells and hypoxia‐resistant STR‐type LSC, capable of repopulating secondary liquid cultures of CRA assays, confirming what was previously shown for normal hematopoiesis. STR‐type LSC were found capable not only of surviving in hypoxia but also of being mostly in cycle, in contrast with the fact that almost all hypoxia‐surviving cells were growth‐arrested and with what we previously found for HSC. However, quiescent LSC were also detected, capable of delayed culture repopulation with the same efficiency as STR‐like LSC. The fact that even quiescent LSC, believed to sustain minimal residual disease in vivo, were found within the MEL cells indicates that all main components of leukemia cell populations may be present within clonal cell lines, which are therefore suitable to study the sensitivity of individual components to treatments.

Searching for the Magic Bullet Against Cancer: The Butyrate Saga

n -Butyric acid and its “polymorphic” derivatives have been largely but somehow “blindly” studied in oncology and in red cell diseases with consistent results through decades indicating a strong maturative effect determined by enhancement of gene transcription. Although these effects have been observed mainly in vitro, the relative absence of systemic toxicity of butyrates render these compounds appealing as specific therapeutic agents. More interestingly, their specific mechanism of action, i.e. inhibition of histone deacetylase and de-repression of transcription represents at present an unique tool for diseases such as acute leukemias which are characterised by a disregulation of co-repressors and co-activators of gene transcription. More insight into specificity and modalities of action of different butyrate derivatives may be a guarantee for excellent tailored antileukemic therapy in the future.

Dasatinib is safe and effective in unselected chronic myeloid leukaemia elderly patients resistant/intolerant to imatinib

To highlight dasatinib role in the elderly, 125 unselected patients with CP-CML aged >60 years resistant/intolerant to imatinib were retrospectively evaluated. Grade 3-4 haematological and extra-haematological toxicities were reported in 39 (31.2%) and 34 (27.2%) patients; grade 3-4 haematological toxicity was higher in patients with 140 mg starting dose (50.0% vs 19.6%, p=0.001). Grade 3-4 pleuro-pericardial effusions occurred in 10 patients (8.0%). Dose reductions were more common in patients with 140 mg (88.4% vs 26.7%, p<0.001). Of 122 evaluable patients, 72 (59.1%) had cytogenetic response [12 (9.8%) partial, 60 (49.3%) complete]. Overall, 38/60 patients in complete CyR also achieved a molecular response. Cumulative OS at 24 and 48 months were 93.1% (95% CI 88.4-97.8) and 84.2% (95% CI 74.6-93.7). Dasatinib, at the recommended dose of 100mg/day, is effective and safe also in unselected elderly subjects.

Butyrates and decitabine cooperate to induce histone acetylation and granulocytic maturation of t(8;21) acute myeloid leukemia blasts

Core histones are proteins organized in octamers, to which DNA is wrapped more or less tightly, depending on their acetylation status. Gene transcription is regulated by a complex series of epigenetic modifications, i.e., histone modification such as methylation and acetylation, events determined by the enzymatic activity of histone methyltransferases, and histone acetyltransferases, respectively, the latter counterbalanced by histone deacetylases (HDAC). Acetylation of histones facilitates destabilization of DNA–nucleosome interaction and renders DNA more accessible to transcription factors. Methylation of different specific lysine residues of histones is differently linked to euchromatin (transcripted DNA) or heterochromatin (silenced DNA). On the other hand, methylation of the promoter regions of some genes by DNA methyltransferases (DNMT) leads to transcriptional silencing and is a common mechanism to regulate gene expression. In normal eukaryotic cells, DNA methylation and histone acetylation are interdependent and maintain equilibrium, allowing temporal expression of genes. In neoplastic cells, this balance is frequently disrupted. In leukemic cells, hypermethylation of CpG islands in the promoter region of genes critical for cell cycle and maturation is frequent, and DNMTs were found to be overexpressed, findings paralleled by evidence of transcriptional repression of downstream genes. Therefore, the combination of HDAC and DNMT inhibitors has been considered to be a possible therapeutic approach to restore normal gene expression in acute myeloid leukemia (AML) and other diseases. Human AML1/ETO Kasumi cells were exposed to the HDAC inhibitor D1 (O-n-butanoil-2,3-O-isopropylidene-alpha-d-mannofuranoside) and 5-aza-deoxycytidine (decitabine) alone and in combination. Histone acetylation as measured by flow cytometry was increased following treatment with D1 and the combination of D1 and decitabine. Addition of D1 alone or in combination with decitabine also led to inhibition of cell proliferation and induction of apoptosis. Thus, treatment of AML with HDAC inhibitors such as D1 and DNMT inhibitors such as decitabine might have clinical benefit for patients, especially these presenting subtypes of AML, like AML1/ETO, in which the leukemogenic mechanism involves corepressor protein complexes containing HDAC and DNMT.