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Introduction: In chronic myeloid leukemia (CML), about half of the patients achieving a deep and stable molecular response with tyrosine kinase inhibitors (TKIs) may discontinue TKI treatment without disease recurrence. As such, treatment-free remission (TFR) has become an ambitious goal of treatment. Given the evidence that deepness and duration of molecular response are necessary but not sufficient requisites for a successful TFR, additional biological criteria are needed to identify CML patients suitable for efficacious discontinuation. Leukemia stem cells (LSCs) are supposed to be the reservoir of the disease. Previously, we demonstrated that residual circulating CD34+/CD38-/CD26+ LSCs were still detectable in a consistent number of CML patients during TFR.Methods: CML LSCs could be easily identified by flow-cytometry as they express the CD34+/CD38-/CD26+ phenotype. In this study, we explored the role of these cells and their correlation with molecular response in a cohort of 109 consecutive chronic phase CML patients prospectively monitored from the time of TKI discontinuation.Results: After a median observation time of 33 months from TKI discontinuation, 38/109 (35%) patients failed TFR after a median time of 4 months, while 71/109 (65%) patients are still in TFR. At TKI discontinuation, peripheral blood CD26+LSCs were undetectable in 48/109 (44%) patients and detectable in 61/109 (56%). No statistically significant correlation between detectable/undetectable CD26+LSCs and the rate of TFR loss was found (p = 0.616). The incidence of TFR loss based on the type of TKI treatment was statistically significant for imatinib treatment compared to that of nilotinib (p = 0.039). Exploring the behavior of CD26+LSCs during TFR, we observed fluctuating values that were very variable between patients, and they were not predictive of TFR loss.Discussion: Up to date, our results confirm that CD26+LSCs are detectable at the time of TKI discontinuation and during TFR. Moreover, at least for the observation median time of the study, the persistence of “fluctuating” values of residual CD26+LSCs does not hamper the possibility to maintain a stable TFR. On the contrary, even patients discontinuing TKI with undetectable CD26+LSCs could undergo TFR loss. Our results suggest that factors other than residual LSCs “burden” playing an active role in controlling disease recurrence. Additional studies evaluating CD26+LSCs’ ability to modulate the immune system and their interaction in CML patients with very long stable TFR are ongoing.

Limited information is available on the impact of the COVID-19 pandemic on the management of chronic myeloid leukaemia (CML). The Campus CML network collected retrospective information on 8665 CML patients followed at 46 centres throughout Italy during the pandemic between February 2020 and January 2021. Within this cohort, we recorded 217 SARS-CoV-2-positive patients (2·5%). Most patients (57%) were diagnosed as having SARS-CoV-2 infection during the second peak of the pandemic (September 2020 to January 2021). The majority (35%) was aged between 50 and 65years with a male prevalence (73%). Fifty-six percent of patients presented concomitant comorbidities. The median time from CML diagnosis to SARS-CoV-2 infection was six years (three months to 18years). Twenty-one patients (9·6%) required hospitalization without the need of respiratory assistance, 18 (8·2%) were hospitalized for respiratory assistance, 8 (3·6%) were admitted to an intensive care unit, while 170 (78%) were only quarantined. Twenty-three percent of patients discontinued tyrosine kinase inhibitor (TKI) therapy during the infection. Twelve patients died due to COVID-19 with a mortality rate of 5·5% in the positive cohort and of 0·13% in the whole cohort. We could also document sequelae caused by the SARS-CoV-2 infection and an impact of the pandemic on the overall management of CML patients.

A limited amount of data has been published in chronic-phase chronic myeloid leukemia (CP-CML) patients aged75 years treated frontline with second-generation tyrosine kinase inhibitors.To address this issue in a clinical 'real-life' setting, we retrospectively analyzed 45 CP-CML patients (pts) followed in 20 Italian Centers and treated frontline with dasatinib (DAS).Median age was 78.4 years (range 75-89.2 years). DAS starting dose was 100 mg QD in 35 pts (77.7%), 80 mg QD in 1 pts (2.2%) and 50 mg QD in 9 pts (20.1%), respectively. The median follow-up was 42.6 months (IQR 20.4 - 63.3).Grade 3 and 4 side effects, both hematological and non-hematological, were detected in 6 (13.3%) and 12 (26.6%) pts, respectively. Pleural effusions of all grades occurred in 13 pts (28.8%) after a median period of DAS exposure of 14.7 months (IQR 3.0 - 33.1). The rates of DAS dose reduction and permanent drug discontinuation were 53.3% and 20.0%, respectively. As the best response, 42/45 patients (93.3%) achieved a complete cytogenetic response (CCyR), 35/45 (77.7%) a major molecular response (MMR) and 24/45 (53.3%) a deep molecular response (both MR 4.0 and MR 4.5). Only 1 patient (2.2%) progressed to the blast phase after 13 months of therapy; 8 deaths were observed (1 CML-related and 7 CML-unrelated). Cumulative event-free survival and overall survival at 36 months were 64.7% (95%, CI 49.4 - 80.0) and 82.3% (95%, CI 70.3-94.3), respectively.These findings, although evaluated in a limited and selected cohort of patients, suggest that DAS might be effective in older patients (aged75 years) affected by CP-CML with acceptable toxicity.

Background Ruxolitinib (Ruxo), an orally bioavailable and selective inhibitor of JAK1 and JAK2, significantly reduces splenomegaly and disease-related symptoms in patients with myelofibrosis (MF). However, no clear survival benefit has been demonstrated, which may in part reflect suboptimal drug exposure related to lower dosages needed to minimize hematological toxicity, specifically cytopenias. Furthermore, the optimal management of specific conditions such as leukocytosis or thrombocytosis in patients under ruxolitinib therapy is still undefined. In these cases, combining ruxolitinib with a cytoreductive agent like hydroxyurea (HU) might improve hematological response. Aims: To evaluate the efficacy and safety of Ruxo and HU combination. Methods This observational multicenter study, conducted from April 2012 to April 2017, enrolled 20 adult patients with a confirmed diagnosis of primary myelofibrosis (PMF), post-polycythemia vera (PPV-MF), or post-essential thrombocythemia (PET-MF) with hyperproliferative manifestations of the disease not controlled by Ruxo therapy. All patients we enrolled into the study had received Ruxo at a starting dose based on baseline platelet count. Patients were included into the study when Ruxo proved to be unable to reduce WBC and/or platelet count to within normal range (WBC Results The addition of HU was started after a median time of ruxolitinib monotherapy of 6.5 months (range 1-49.6 months): 17 patients (85%) started HU treatment due to lack of WBC control, whereas the remaining 3 patients (15%) started for the lack of platelet control. While on Ruxo monotherapy, ten patients (50%) needed a dose reduction due to hematological toxicity and three patients temporarily discontinued Ruxo due to severe thrombocytopenia (15%). After 14.5 months (range 2-195) median time of combination therapy in 8 patients the Ruxo daily doses increased (mean increase = 5.1 mg BID), in 9 the dose was unchanged despite the addition of HU, and only in three cases the ruxolitinib dose had to be reduced (mean reduction = 3.4 mg BID). Overall, the mean daily dose of Ruxo administered to the whole cohort of patients increased by 1.8 mg BID (P=.013), and only one patient had to discontinue Ruxo, due to severe thrombocytopenia. Non-hematological adverse events were not observed. Among the 17 patients who started combination therapy to control WBC count, 14 (82.3%) obtained a WBC response, whereas, among the three patients who started HU in association with Ruxo in order to reduce platelets count, two (66.6%) achieved a platelet response. In addition, 12 patients of the whole study cohort had clinical improvement in MF-associated symptomatic burden, with 9 of them showing spleen and symptoms response and the remaining three only spleen response. Thus, a clinical response of any type was obtained in 8 patients (40%) during Ruxo monotherapy and in 17 patients (85%) during Ruxo-HU combination (P=.003). Of note, all 8 patients in which Ruxo dose was increased during combination had at least one type of drug-related clinical response. Conclusion In conclusion, the combination of HU with Ruxo yielded a high clinical response rate and increased Ruxo exposure in patients with hyperproliferative forms of MF. The association was very well tolerated, and the hematological toxicities mostly and were generally manageable with dose reductions and/or supportive treatment. Disclosures Pane: AMGEN: Speakers Bureau; Novartis: Research Funding, Speakers Bureau; BMS: Speakers Bureau.

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An observational prospective study was conducted by the CML Italian network to analyze the role of baseline patient characteristics and first line treatments on overall survival and CML-related mortality in 1206 newly diagnosed CML patients, 608 treated with imatinib (IMA) and 598 with 2nd generation tyrosine kinase inhibitors (2GTKI). IMA-treated patients were much older (median age 69 years, IQR 58-77) than the 2GTKI group (52, IQR 41-63) and had more comorbidities. Estimated 4-year overall survival of the entire cohort was 89% (95%CI 85.9-91.4). Overall, 73 patients (6.1%) died: 17 (2.8%) in the 2GTKI vs 56 (9.2%) in the IMA cohort (adjusted HR=0.50; 95% CI=0.26-0.94), but no differences were detected for CML-related mortality (10 (1.7%) vs 11 (1.8%) in the 2GTKIs vs IMA cohort (sHR=1.61; 0.52-4.96). The ELTS score was associated to CML mortality (high risk vs low, HR=9.67; 95%CI 2.94-31.74; p

Recommendations for dyslipidemia management aimed at reducing arterial occlusive events (AOEs) have been recently published. So far, no data have been reported on the management of dyslipidemia in chronic myeloid leukemia (CML) patients treated with nilotinib. We investigated 369 CML adult patients, stratified according to the new Systematic Coronary Risk Evaluation (SCORE) scoring system. Plasma levels of cholesterol, HDL, LDL, and triglycerides were measured prior to the start of nilotinib and after 3, 6, and 12months. The 5-year cumulative incidence of AOEs was 15.9%. Patients with cholesterol levels > 200mg/dL and LDL > 70mg/dL 3months after treatment showed a significantly higher incidence of AOEs (21.9 ± 4.6% vs 6.2 ± 2.5, P= 0.003). Patients belonging to the high and very high SCORE risk group showed a significant increase of AOEs (34.4 ± 6% vs 10 ± 2.1%, P< 0.001). In multivariate analysis, both high cholesterol and LDL levels and a high and very high SCORE risk remained significantly associated with the risk of AOEs (P= 0.008; HR = 3.5; 95% CI = 1.4–8.7 and P < 0.001; HR = 4.4; 95% CI = 2–9.8, respectively). Overall, 78 patients (21.1%) presented dyslipidemia at the time of CML diagnosis and 88 (23.3%) after starting nilotinib, but only 26 of them (29.5%) were treated with statins. Low LDL and cholesterol plasma levels are associated with a significant lower risk of AOEs in CML patients treated with nilotinib in the real life.

Hypertension is a commonly reported comorbidity in patients diagnosed with chronic myeloid leukemia (CML), and its management represents a challenge in patients treated with 2nd- or 3rd-generation tyrosine kinase inhibitors (TKIs), considering their additional cardiovascular (CV) toxicity. The renin angiotensin system (RAS) contributes to hypertension genesis and plays an important role in atherosclerosis development, proliferation, and differentiation of myeloid hematopoietic cells. We analyzed a cohort of 192 patients with hypertension at CML diagnosis, who were treated with 2nd- or 3rd-generation TKIs, and evaluated the efficacy of RAS inhibitors (angiotensin-converting enzyme inhibitors (ACEi) and angiotensin-II receptor blockers (ARBs)) in the prevention of arterial occlusive events (AOEs), as compared with other drug classes. The 5-year cumulative incidence of AOEs was 32.7 ± 4.2%. Patients with SCORE ≥ 5% (high-very-high) showed a significantly higher incidence of AOEs (33.7 ± 7.6% vs 13.6 ± 4.8%, p = 0.006). The AOE incidence was significantly lower in patients treated with RAS inhibitors (14.8 ± 4.2% vs 44 ± 1%, p < 0.001, HR = 0.283). The difference in the low and intermediate Sokal risk group was confirmed but not in the high-risk group, where a lower RAS expression has been reported. Our data suggest that RAS inhibitors may represent an optimal treatment in patients with hypertension and CML, treated with 2nd or 3rdG TKIs.

No abstract available.

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Background Role of erythropoietin (EPO) in the treatment of late anemia in patients with Chronic Myeloid Leukemia (CML) is still undefined. Methods Fifty CML patients treated at 14 institutions with frontline imatinib for at least 12 months and in stable complete cytogenetic response who developed a late chronic anemia treated with EPO were retrospectively evaluated. Results Median time from imatinib start to EPO treatment was 42.2 months [interquartile range (IQR) 20.8-91.9]. Median Hb value at EPO starting time was 9.9 g/dL (IQR 8.9-10.3): Eleven patients (22.0%) were transfusion dependent. Alpha-EPO (40 000 UI weekly) was employed in 37 patients, beta-EPO (30 000 UI weekly) in 9 patients, zeta-EPO (40 000 UI weekly) in 2 patients, and darbepoetin (150 mcg/weekly) in the remaining 2 patients. On the whole, 41 patients (82.0%) achieved an erythroid response, defined as a stable (>3 months) improvement >1.5 g/dL of Hb level, and 9 patients (18.0%) indeed resulted resistant. Among responding patients, 10 relapsed after a median time from EPO start of 20.7 months (IQR 10.8-63.7). No EPO-related toxicity was observed. Conclusions Results of EPO treatment for late chronic anemia during long-lasting imatinib therapy are encouraging, with a high rate of response.

Introduction Tyrosine kinase inhibitors (TKIs) have dramatically changed the outcome of chronic phase chronic myeloid leukemia patients (CP-CML),improving the long-term outcome; indeed, life expectancy is now very close to that of age matched individuals in the general population. Imatinib (IMA) the first generation TKI, increased the overall survival(OS)by more than 80%. Second-generation TKIs, (2gen TKIs) used in first line dasatinib and nilotinib, induced faster molecular responses, rapidly reducing the disease burden, but did not change the OS of CP-CML newly diagnosed patients. Most of the available data reported were extrapolated from sponsored clinical trials. The aim of this analysis is to detail and analyze the prognostic features influencing the OS in a large Italian CML cohort of patients prospectively enrolled in the GIMEMA CML Italian study. Methods Relevant clinical, demographic, biological and treatment-related information were web-based collected during a multicenter,observational Italian study that enrolled consecutive patients in each disease phase, at 68 Italian hematologic centers belonging to the GIMEMA network from January 2013 to June 2020. We analyzed prognostic factors influencing the OS by Kaplan Meier method and Cox multivariable models. Results A cohort of 1206 patients was prospectively analyzed, 608 of them received frontline IMA and 598 2genTKIs. Median age in the IMA cohort was 69 years (range 58-77) vs 52 years in the 2genTKIs cohort (range 41-63). The male/female ratio was 1.7 in the IMA group and 1.35 in the 2genTKIs cohort. Ninety-eight percent of patients were in CP. Results of molecular analysis of the BCR-ABL transcript at baseline showed: b2a2 in 33.1 % of patients and b3a2 in 59.9%, while an atypical transcript was found in 7%. The cytogenetic analysis at baseline showed major and minor additional aberrations in 5.7% and 1.6% of patients respectively. In the IMA cohort,according to the Sokal score, 27.7%, 57.3% and 15% of patients were stratified as low, intermediate and high risk, whereas according to the ELTS score 51.3%, 35.5% and 13.3%, of patients were classified as low, intermediate and high risk. In the 2genTKIs cohort, according to the Sokal score, 44.8%, 34.5% and 20.8%, were low, intermediate and high risk, respectively, whereas according to the ELTS score, 66.9%, 22% and 11% were assigned to the respective risk groups.The Charlson comorbidity index in the IMA cohort was 2-3 and 4-5 in 74% and 26% of patients respectively; in the 2genTKIs cohort the score was 2-3 in 89% and 4-5 only in 10% of patients. Overall, median follow-up of the whole population was 24.7 months (range 13.3-39.3).Seventy-three patients (6.1%) in the overall population died, the majority of them in the IMA cohort: 56 patients (9.2%), at median age of 80.5 years,11/608 (1.8%) due to CML-related causes. Conversely,in the 2genTKIs cohort only 17 patients (2.8%) died, at a median age of 62 years, 10/598 (1.7%) for CML-related causes. Estimated 60-months OS of the overall population was 86.4% (95% CI 81.3-90.2): 75.8% (95% CI 64.5-84) in the IMA cohort and 93.8% (95% CI 87.5-97) in the 2genTKIs group (p Conclusions In this first analysis of our study different clinical behaviors were observed among Italian hematologists, who prevalently prescribed IMA to older patients,with more comorbidities, as compared to 2genTKIs.These differences explain a better OS for patients treated with 2genTKIs vs IMA, however, the risk of death for CML related causes is quite similar between the two groups, all the differences being attributable to other causes of death.Prognostic baseline features associated to an increased OS confirmed that, in addition to age, the ELTS score and the comorbidities are the main clinical factors that independently influence the long-term OS Disclosures Pregno: Incyte-Italy,: Membership on an entity's Board of Directors or advisory committees, Other: conference reports; Novartis-Italy: Membership on an entity's Board of Directors or advisory committees, Other: conference reports; Pfizer-Italy: Membership on an entity's Board of Directors or advisory committees, Other: conference reports. Breccia:Bristol-Myers Squibb/Celgene: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Abbvie: Consultancy. Castagnetti:Novartis: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Incyte: Consultancy, Honoraria. Galimberti:Novartis: Speakers Bureau; Incyte: Honoraria. Bocchia:CELGENE: Honoraria; Incyte: Honoraria. Abruzzese:Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bms: Honoraria; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees. Levato:Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Rosti:Pfizer: Research Funding, Speakers Bureau; Bristol-Myers Squibb: Speakers Bureau; Novartis: Speakers Bureau; Incyte: Speakers Bureau. Di Raimondo:GILEAD, Incyte: Research Funding; Amgen, Takeda, Novartis: Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; GSK: Consultancy, Honoraria. Pane:Janssen: Other: Travel Expenses; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis pharma SAS: Consultancy, Other: Travel Expenses, Research Funding, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Other: travel expenses, Speakers Bureau; Daiichi Sankyo: Consultancy, Other: Travel Expenses; Amgen: Consultancy, Other: Travel Expenses, Speakers Bureau; AbbVie: Consultancy, Other: Travel Expenses, Speakers Bureau. Foà:Incyte: Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees; Novartis: Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Saglio:Bristol-Myers Squibb: Research Funding; Pfizer: Research Funding; Incyte: Research Funding; Roche: Research Funding; Novartis: Research Funding; Ariad: Research Funding.

Introduction Treatment of chronic phase (CP) chronic myeloid leukemia (CML) with tyrosine kinase inhibitors (TKIs) proved to be almost equally effective in young and elderly patients. Three TKIs, imatinib (IM), dasatinib (DAS) and nilotinib (NIL), are approved for frontline therapy in Italy. Choice of frontline TKI is based on a combined evaluation of patient's characteristics and expectations, with age usually playing a prominent role. However, to date, few data are available on patterns of TKI selection in very elderly patients. Aim To analyse the use of frontline TKI therapy in a large and unselected cohort of very elderly CP-CML patients Methods We retrospectively evaluated 332 patients aged ≥75 year diagnosed from 1/2012 to 12/2019 at 36 Hematology Centres participating at the "Campus CML" project. Results Clinical features at diagnosis for the whole cohort and according to frontline TKI are reported in Table 1. As to frontline TKI, 285 patients (85.8%) received IM and 47 (14.2%) a 2G-TKI (DAS n=28, 59.5%; NIL n=19, 40.5%). Of the 285 IM-treated patients, 192 (67.3%) started with standard dose (400 mg/day) and 93 (32.7%) with a reduced dose (300 mg/day n=64, 22.5%; Following widespread introduction of generic IM in Italy in early 2018, patients were divided in 2 groups: among 238 patients diagnosed from 2012 to 2017, 198 (83.1%) received IM and 40 (16.9%) a 2G-TKI, while patients diagnosed in 2018-2019 were treated with IM in 87/94 (92.5%) cases and with a 2G-TKI in 7 (7.5%) cases only (p=0.028). Conclusions IM remains the frontline drug of choice in very elderly CML patients, and this trend seems to increase after the introduction of the generic formulation. However, 2G-TKI are used in a small but sizeable group of patients, without a clear correlation with baseline CML features, thus probably reflecting a physician's evaluation of patient's fitness and/or expectation. Efficacy and safety of initial reduced TKIs doses in the setting of very elderly patients warrant further analyses. Figure 1 Figure 1. Disclosures Latagliata: Novartis: Honoraria; BMS Cellgene: Honoraria; Pfizer: Honoraria. Bonifacio: Novartis: Honoraria; Pfizer: Honoraria; Amgen: Honoraria; Bristol Myers Squibb: Honoraria. Elena: CELGENE: Other: funding for meeting participation; PFIZER: Membership on an entity's Board of Directors or advisory committees; NOVARTIS: Membership on an entity's Board of Directors or advisory committees; GILEAD: Membership on an entity's Board of Directors or advisory committees. Iurlo: Novartis: Speakers Bureau; Incyte: Speakers Bureau; Pfizer: Speakers Bureau; Bristol Myers Squibb: Speakers Bureau. Sportoletti: AstraZeneca: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria. Stagno: Pfizer: Consultancy, Honoraria, Other: Support for attending meetings and/or travel; InCyte: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Other: Support for attending meetings and/or travel, Research Funding. Abruzzese: Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria. Breccia: Bristol Myers Squibb/Celgene: Honoraria; Incyte: Honoraria; Abbvie: Honoraria; Pfizer: Honoraria; Novartis: Honoraria.

Background: Tyrosine kinase inhibitors (TKI) may offer a normal life expectancy to Chronic Myeloid Leukemia (CML) patients. However, during treatment with nilotinib, a higher than expected incidence of arterial occlusive events (AOEs) was observed. We retrospectively showed an "inflammatory status" during nilotinib treatment that may explain this increased incidence of AOEs. Here, we report results of a prospective multicenter (KIARO) study including 186 CML patients (89 imatinib, 59 nilotinib, 38 dasatinib) in which pro/anti-inflammatory cytokines were measured at diagnosis and during treatment, with the aim to investigate potential changes in each patient's inflammatory status possibly favoring AOEs. Aims: The aims of this study are: 1) to analyze prospectively inflammation status during TKI treatment; 2) to record AOEs; 3) to calculate the SCORE and evaluate its predictive role for AOEs; 4) to analyze possible associations of AOEs with altered inflammation status. Methods: Inflammatory status was evaluated by measuring IL6, IL10, TNFα, oxLDL and hs-CRP plasma levels at diagnosis and during treatment (+1, +3, +6, +12 months); additionally, clinical and biochemical pro-atherothrombotic profiles and the 10-year SCORE chart were also evaluated. Results: 186 newly-diagnosed CML patients starting either imatinib, nilotinib or dasatinib treatment, entered this study. Regarding the inflammation status, we observed that TNFα and IL6 levels were high at diagnosis and decreased during the first 12 months of treatment regardless the type of TKI; instead, IL10 levels were comparable among the 3 TKI cohorts at baseline, but showed a remarkably different evolution during treatment. In fact, IL10 levels were significantly higher after 6 and 12 months of imatinib (p=0.012 and p=0.009, respectively) and dasatinib (p=0.032 and p=0.014, respectively) compared to nilotinib. Consequently, TNFα/IL10 ratio was significantly higher in nilotinib cohort at 6 and 12 months respect to imatinib (p=0.044 at 6 months and p=0.041 at 12 months) and dasatinib (p=0.040 at 6 months and p=0.044 at 12 months). As well, IL6/IL10 ratio was significantly higher in nilotinib cohort compared to imatinib and dasatinib both at 6 (p=0.042 and p=0.049, respectively) and 12 months (p=0.040 and p=0.041, respectively) (Figure 1). OxLDL levels were similar in the 3 groups for the first 6 months. At 12 months we detected a significant increase of oxLDL levels in the nilotinib cohort (p=0.041), respect to imatinib and dasatinib. We did not find significant differences in hs-CRP levels across the 3 TKIs, although a trend for higher levels was observed in nilotinib cohort. Overall, these results suggest a TKI-driven pro-inflammatory status in nilotinib treated patients. After a median follow-up of 23.3 months of TKI treatment, 10 patients (5.4%) suffered an AOE, specifically: 6 ACS, 2 PAOD, 1 TIA and 1 stroke. 5 events (50%) occurred in patients treated with nilotinib, either in first line (4 patients) or in third line (1 patient, after failure following brief treatment with imatinib and dasatinib). In this subgroup of 10 patients experiencing an AOE, we observed a trend of increased IL6 and TNFα median values both at diagnosis and at each time point, compared with the remaining no-AOE patients. IL10 and oxLDL had similar median concentrations in both AOE and no-AOE cohorts, except for oxLDL at 12 months which resulted higher in patients who experienced AOEs. Moreover, regarding AOEs, nilotinib treatment showed a 3.1 times increased risk compared to other TKIs (HR 3.1, 95% CI 2.6-4.4 p< 0.001), whereas 10-year SCORE was not predictive in the whole cohort (HR 0.6, 95% CI 0.33-0.94 p= 0.094) or in any subgroup (imatinib HR 0.8, 95% CI 0.49-1.03 p= 0.067; nilotinib HR 0.4, 95% CI 0.29-0.76 p= 0.112, dasatinib HR 0.6, 95% CI 0.37-0.92 p= 0.082). Conclusions: Our results showed a pro-inflammatory/oxidative milieu increasing along treatment with nilotinib compared with imatinib or dasatinib, as demonstrated by higher IL6/IL10 and TNFα/IL10 ratios, higher levels of oxLDL and a trend for higher hs-CRP only in nilotinib cohort. However, due to the low number of observed events, a formal statistical analysis for any association between AOEs and pro/anti-inflammatory cytokines levels was not possible. Therefore, a longer follow-up is needed to further confirm the active role of nilotinib in AOEs pathogenesis. Figure 1 Figure 1. Disclosures Abruzzese: Incyte: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria. Galimberti: Incyte: Speakers Bureau; AbbVie, Janssen: Honoraria, Other: Travel grants. Stagno: Pfizer: Consultancy, Honoraria, Other: Support for attending meetings and/or travel; InCyte: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Other: Support for attending meetings and/or travel, Research Funding.

Background Tyrosine kinase inhibitors (TKIs) revolutionized treatment of chronic myeloid leukemia (CML). However, the first months of therapy are crucial, as optimal response is defined as the achievement of molecular milestones at 3, 6 and 12 months (mo.) and as many toxicities, also causing a TKI switch, are more frequent in the 1st year. Methods To evaluate achievement of early molecular response (MR) and incidence of events leading to a TKI change during the 1st year of therapy, we retrospectively studied 1650 CP-CML patients diagnosed from 2012 and 2019 at 31 Hematology Centres and treated with frontline imatinib (IM) or second-generation (2G) TKIs dasatinib or nilotinib. Optimal MR at 3, 6 and 12 mo. were assessed according to 2020 ELN recommendations. Results Frontline TKI was IM in 926 (56.1%) and 2G-TKIs in 724 (43.9%) cases: the main clinical features at diagnosis of the entire cohort and according to frontline treatment is reported in the Table 1. Commonest comorbidities were arterial hypertension (38.7%), previous neoplasm (13.6%), diabetes (11.3%), peripheral vascular diseases (7.8%), COPD (7.5%) and ischemic heart disease (6.8%). IM-treated patients were older (p Optimal MR was achieved at 3 mo. by 1186/1430 (82.9%), at 6 mo. by 1025/1352 (75.8%) and at 12 mo. by 826/1264 patients (65.3%), respectively. Total number of patients discontinuing TKI in the 1st year was 321/1650 (19.4%), being higher with IM (237/926, 25.5%) than 2G-TKIs (84/724, 11.6%) (p0.001), hematologic toxicity (1.7%, 2.0% IM vs 1.4% 2G-TKIs, p=0.25) and progression (1.0%, 1.2% IM vs 0.8% 2G-TKIs, p=0.56). Cumulative incidence of discontinuation at 3, 6 and 12 mo. were 5.6%, 10.7% and 19.3%, respectively; values for IM and 2G-TKIs at the three timepoints were 8.1%, 15.0%, 25.5% and 2.5%, 5.3%, 11.5% (p Conclusions This real-world study on over 1600 CML patients shows that almost 20% discontinue frontline TKI during the 1st year, mostly for primary resistance or toxicity. Discontinuation rates are higher with IM compared to 2G-TKIs, mostly at 3 mo. and are probably due to a lower attainment of early MR. The impact of older age, higher risks and heavier burden of comorbidities in IM patients should be considered and need deeper investigation. Figure 1 Figure 1. Disclosures Elena: GILEAD: Membership on an entity's Board of Directors or advisory committees; NOVARTIS: Membership on an entity's Board of Directors or advisory committees; PFIZER: Membership on an entity's Board of Directors or advisory committees; CELGENE: Other: funding for meeting participation. Sportoletti: AstraZeneca: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria. Stagno: InCyte: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria, Other: Support for attending meetings and/or travel; Novartis: Consultancy, Honoraria, Other: Support for attending meetings and/or travel, Research Funding. Iurlo: Pfizer: Speakers Bureau; Incyte: Speakers Bureau; Novartis: Speakers Bureau; Bristol Myers Squibb: Speakers Bureau. Bonifacio: Novartis: Honoraria; Pfizer: Honoraria; Amgen: Honoraria; Bristol Myers Squibb: Honoraria. Breccia: Pfizer: Honoraria; Incyte: Honoraria; Abbvie: Honoraria; Bristol Myers Squibb/Celgene: Honoraria; Novartis: Honoraria. Latagliata: Novartis: Honoraria; Pfizer: Honoraria; BMS Cellgene: Honoraria.

Simple Summary The introduction to clinical practice of a treatment-free remission approach in chronic myeloid leukemia patients with a stable deep molecular response highlighted how crucial it is to monitor the molecular levels of BCR–ABL1 as accurately and precisely as possible. In this context, the droplet digital PCR (ddPCR) presents an alternative methodology for such quantification. To hypothesize the introduction of this technology in routine practice, we performed a multicentric study that compares ddPCR with the standard methodology currently used. Our results demonstrate that the use of ddPCR in clinical practice is feasible and could be beneficial. Abstract BCR–ABL1 mRNA levels represent the key molecular marker for the evaluation of minimal residual disease (MRD) in chronic myeloid leukemia (CML) patients and real-time quantitative PCR (RT-qPCR) is currently the standard method to monitor it. In the era of tyrosine kinase inhibitors (TKIs) discontinuation, droplet digital PCR (ddPCR) has emerged to provide a more precise detection of MRD. To hypothesize the use of ddPCR in clinical practice, we designed a multicentric study to evaluate the potential value of ddPCR in the diagnostic routine. Thirty-seven RNA samples from CML patients and five from healthy donors were analyzed using both ddPCR QXDxTM BCR-ABL %IS Kit and LabNet-approved RT-qPCR methodologies in three different Italian laboratories. Our results show that ddPCR has a good agreement with RT-qPCR, but it is more precise to quantify BCR–ABL1 transcript levels. Furthermore, we did not find differences between duplicate or quadruplicate analysis in terms of BCR–ABL1% IS values. Droplet digital PCR could be confidently introduced into the diagnostic routine as a complement to the RT-qPCR.

Introduction. New guidelines for the management of dyslipidemia and lipid modification in order to reduce the risk of cardiovascular (CV) events have been recently published by the European Society of Cardiology (ESC) and the European Atherosclerosis Society (EAS). New recommendations regarding the target value of plasma lipids in very high and high CV risk patients have been provided, in addition to an estimate of the CV risk with a new Systematic Coronary Risk Evaluation (SCORE) chart. Few data have been reported on the management of dyslipidemia in chronic myeloid leukemia (CML) patients treated with nilotinib, and the association with arterial occlusive events (AOEs). We therefore analyzed a large real-life cohort of Italian patients with CML treated with nilotinib outside of clinical trials and evaluated the association between AOEs and plasma lipoproteins levels; moreover, we estimated the prognostic value of the new SCORE chart to predict AOEs. The secondary endpoint was to report the management of dyslipidemia in the clinical practice. Methods. We identified 233 adult patients with CML who were treated in 20 Italian centers with nilotinib. All patients were stratified into low to moderate (SCORE ≤ 5%) or high to very high (SCORE risk >5%) CV risk, according to the new version of the SCORE 2019. We recorded concentration levels of cholesterol, high-density lipoproteins (HDL), low-density lipoproteins (LDL) and triglycerides at diagnosis of CML, before starting ponatinib and therefore after 3, 6 and 12 months of treatment. All AOEs (cerebrovascular, peripheral vascular and CV events excluding hypertension) were considered. Results. The median age was 50 years (range 20-88) and the Sokal score was intermediate-high in 45.5% of patients. The median follow-up was 5 years (range 3.4-10.5). Nilotinib was administered as first line of therapy in (72%) of cases or second or subsequent lines of treatment for inefficacy (20.9%) or intolerance (7.1%). At baseline, nilotinib was administered at the following doses: 800 mg/day in 9.3% of patients, 600 mg/day in 87% of patients, 400 mg/day in 3.1% of patients and 300mg in 0.6% of patients, respectively. The median time of drug exposure was 60 months (range 2-155). The 48-month cumulative incidence rate of AOEs was 14.1±2.7%. Patients with cholesterol plasma levels > 200 mg/dL and LDL >70 mg/dL at baseline and 3 months after starting nilotinib, showed a significantly higher incidence of AOEs (24.5±7.3% vs 11±2.7%, P=0.02 and 22.3±4.9% vs 5.9±2.6, P=0.003, respectively) Figure 1. Patients with triglycerides levels > 200 mg/dL 3 months after starting nilotinib, showed a significantly higher incidence of AOEs (56±20.5% vs 13.3±2.7%, P=0.011) Patients belonging to the high and very high SCORE risk group showed a significant increase of AOEs (32.8.1±9% vs. 9±1%±2.6%, p=0.001). In multivariate analysis, statistical significance of cholesterol plasma levels > 200 mg/dL and LDL >70 mg/dL after 3 months and high-very-high SCORE was maintained (P=0.018, HR=3.4, 95% CI=1.2-9.4 and P=0.004, HR=3.5, 95% CI=1.5-8.2, respectively). Overall, 46 patients (20.5%) presented dyslipidemia at CML diagnosis and 65 (29%) at the start of treatment with nilotinib. Despite dyslipidemia, only 6 patients were taking statins during the treatment with nilotinib and only 5 started it after 3 months of nilotinib: 3 patients were treated with rosuvastatin and 2 with pravastatin. Conclusions. Our findings suggest that a proper control of dyslipidemia, keeping cholesterol and triglycerides plasma levels ≤ 200 mg/dL and LDL ≤70 mg/dL is associated with reduced risk of AOEs in CML patients treated with nilotinib. An under estimation of the clinical importance of elevated plasma lipids as a risk factor for AOEs events represents a possible issue in the real-life. Figure 1 Disclosures Abruzzese: Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bms: Honoraria; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees. Galimberti:Incyte: Honoraria; Novartis: Speakers Bureau. Castagnetti:Novartis: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria. Pregno:Incyte-Italy,: Membership on an entity's Board of Directors or advisory committees, Other: conference reports; Novartis-Italy: Membership on an entity's Board of Directors or advisory committees, Other: conference reports; Pfizer-Italy: Membership on an entity's Board of Directors or advisory committees, Other: conference reports. Bocchia:CELGENE: Honoraria; Incyte: Honoraria. Gugliotta:Novartis: Honoraria; Incyte: Honoraria; Pfizer: Honoraria. Foà:Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees; Incyte: Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees.

Background Limited information is available regarding the rate of long-term cardiovascular (CV) mortality in chronic myeloid leukaemia (CML) patients treated with second- and third-generation tyrosine kinase inhibitors (2ndG/3rdG TKIs) in the real-life practice. Methods We identified 656 consecutive CML patients treated with nilotinib, dasatinib, bosutinib and ponatinib. Results The 15-year CV-mortality free survival was 93 ± 2.8%. Age ≥65 years (p = 0.005) and a positive history of CV disease (p = 0.04) were significantly associated with a lower CV-mortality free survival. CV disease accounted for 16.5% and 5% of potential years of life lost (PYLL) in male and female patients, respectively. The standard mortality ratio (SMR) following ischemic heart disease (IHD) was 3.9 in males and 3.8 in female patients, meaning an excess of IHD deaths observed, in comparison with the population of control. Conclusion. Prevention strategies based on CV risk factors, in particular in those patients with a previous history of CV disease, should be considered.

Background Risk of death is particularly high in patients with a previous history of arterial occlusive events (AOEs) and the probability for a recurrent event is around 20%. Little is known about recurrent AOE and the role of secondary prevention in patients with Chronic Myeloid Leukemia (CML) with previous AOE, treated with second- and third-generation tyrosine kinase inhibitors (2ndG/3rdG TKIs), nilotinib, dasatinib, bosutinib and ponatinib. Methods We identified a real-life cohort of 57 consecutive adult CML patients treated with 2ndG/3rdG TKI. All patients had a previous history of AOE. Ongoing use of secondary prevention of AOE (including antiplatelet agents, anticoagulant therapy, and statins) before starting a 2ndG/3rdG TKI was recorded, as well as CV risk factors. Results The 60-month cumulative incidence rate of recurrent AOEs was 47.8 ± 10.9%. Despite a history of AOE, 10 patients (16%) were not receiving secondary preventative measures. Patients treated with nilotinib and ponatinib showed a higher incidence of recurrent AOEs (76.7 ± 14.3% and 64 ± 20.1%, respectively) than those treated with dasatinib and bosutinib (44 ± 24.2% and 30.5 ± 15.5%, respectively) (p = 0.01). Only treatment with a 2ndG/3rdG TKI given as second or subsequent line therapy showed a significant association with an increased incidence of recurrent AOE (p = 0.039). Overall, 17 recurrent AOEs were observed; 3 CV-related deaths were reported. Conclusion CML patients with a previous history of AOE treated with 2ndG/3rdG TKI represent a particular patient population with a higher probability of experiencing a recurrent AOE; individualized treatment is needed to optimize secondary prevention.

Very elderly (> 75years) chronic myeloid leukaemia (CML) patients at diagnosis are sometimes treated with different doses of imatinib (IM) based on concomitant diseases and physicians’ judgement. However, data on long-term follow-up of these patients are still lacking. To investigate treatment response and outcome, we retrospectively revised an Italian database of 263 very elderly CML patients receiving IM from the time of diagnosis. Median age at diagnosis was 78.5years and 56% of patients had 2 or 3 comorbidities. A complete haematological and cytogenetic response were achieved in 244 (92.8%) and 184 (69.9%) patients, respectively. In 148 cases (56.2%), a major molecular response was observed, which was deep in 63 cases (24%). A blastic phase occurred in 11 patients (4.2%). After a median follow-up of 45.0months, 93 patients have died (9 from disease progression) and 104 (39.5%) are still in treatment with IM. Incidence of grades 3–4 haematological and non-haematological toxicity was similar to those reported in younger patients. Five-year event-free survival was 54.5% and 45.2% in patients ≤80years and > 80years, respectively (p = 0.098). Five years OS was 75.7% and 61.6% in patients ≤80years and > 80years, respectively (p = 0.003). These findings show that IM plays an important role in frontline treatment of very elderly CML patients without increased toxicity and any effort to treat these patients with standard doses should be made in order to achieve responses as in younger subjects.

BCR-ABL1 kinase domain (KD) mutation status is considered to be an important element of clinical decision algorithms for chronic myeloid leukemia (CML) patients who do not achieve an optimal response to tyrosine kinase inhibitors (TKIs). Conventional Sanger sequencing is the method currently recommended to test BCR-ABL1 KD mutations. However, Sanger sequencing has limited sensitivity and cannot always discriminate between polyclonal and compound mutations. The use of next-generation sequencing (NGS) is increasingly widespread in diagnostic laboratories and represents an attractive alternative. Currently available data on the clinical impact of NGS-based mutational testing in CML patients do not allow recommendations with a high grade of evidence to be prepared. This article reports the results of a group discussion among an ad hoc expert panel with the objective of producing recommendations on the appropriateness of clinical decisions about the indication for NGS, the performance characteristics of NGS platforms, and the therapeutic changes that could be applied based on the use of NGS in CML. Overall, these recommendations might be employed to inform clinicians about the practical use of NGS in CML.

Arterial occlusive events (AOEs) represent emerging complications in chronic myeloid leukemia (CML) patients treated with ponatinib. We identified 85 consecutive CML adult patients who were treated with ponatinib in 17 Italian centers. Patients were stratified according to the Systematic Coronary Risk Evaluation (SCORE) assessment, based on sex, age, smoking habits, systolic blood pressure, and total cholesterol levels. The 60-month cumulative incidence rate of AOEs excluding hypertension was 25.7%. Hypertension was reported in 14.1% of patients. The median time of exposure to ponatinib was 28months (range, 3-69months). Patients with a high to very high SCORE risk showed a significantly higher incidence rate of AOEs (74.3% vs 15.2%, P&nbsp

Ruxolitinib is the only commercially available JAK1/2 inhibitor approved for the treatment of myelofibrosis-related splenomegaly and symptoms. During treatment, as rare conditions, leukocytosis and/or thrombocytosis could develop and the management of these situations is not well established. We report here 53 myelofibrosis patients that received a combination of hydroxyurea and ruxolitinib because of uncontrolled myeloproliferation. Both drugs were administered outside clinical trials. At 48weeks, a significant reduction in leucocyte and platelet counts was observed (p= 0.02 and p= 0.04, respectively). Additionally, the spleen volume decreased from a median value of 10cm below the left costal margin (range, 0-10) to 6cm (range, 0-15). The rate of spleen response increased from 14% at the start of the combination to 45% after 48weeks. The safety profile of the combination was consistent with that observed with ruxolitinib single agent. These data require further confirmation in large cohorts of patients prospectively assessed.

Background: Monitoring of BCR-ABL1 molecular levels is essential for the management of Chronic Myeloid Leukemia (CML) patients treated with Tyrosine Kinases Inhibitors (TKIs). Real Time Quantitative PCR (RT-qPCR) is currently the standard method for assessing molecular remission (MR) in patients with CML. Recently, droplet digital PCR (ddPCR) has emerged to provide a more accurate detection of minimal residual disease (MRD). In order to hypothesize the use of this new technology in the clinical practice, in the era of TKI discontinuation, we designed a multi-centric study to evaluate the potential value of ddPCR in diagnostic routine. Aims of the study were:1) the evaluation of the agreement between the measures obtained by ddPCR and RT-qPCR and 2) the assessment of the repeatability of the two methods. Methods: Total RNA was extracted from 37 CML patients using Maxwell 16 LEV simplyRNA Blood kit (Promega), following the manufacturer's instructions. Samples were divided in 5 groups based on molecular response (MR) as follow: group 1, MR Statistical analysis: Bland-Altman analysis was performed. For the measurement of the agreement we reported the bias, which is the mean of the difference between the methods, the 95% limits of agreement and the coefficient of variation. Residual variance and coefficients of repeatability (i.e. the upper limits of a prediction interval for the absolute difference between two measurements by the same method on the same item) were computed to achieve the second endpoint. An analysis of sensitivity on the labs was also carried out. All analyses were stratified by the level of disease. Results: A total of 370 measures were included in the analysis, 185 for ddPCR and 185 for RT-qPCR divided as follow: 50 for group 1 and for group 2, 90 for group 3, 4 and 5. In Table 1 we reported the median and interquartile range (IQR) for all levels of disease. Results of the Bland-Altman analysis are shown in Table 2. The coefficients of variation, which expresses the standard deviation as a percentage of the mean, were 2.35, 2.31, 1.10, 1.34, 39.12 in group 1, 2, 3, 4 and 5 respectively. The repeatability coefficients of ddPCR were smaller than qRT-PCR across all the levels of disease, showing a slightly better precision of ddPCR (Table 2). Conclusions: Higher coefficients of variation in group 1 and 2 were probably due to a greater heterogeneity of the patients. In fact, BCR-ABL1/ABL1 levels by RT-qPCR ranged between 1.43 and 6.94 and between 0.10 and 0.25 in group 1 and in group 2 respectively (Table 1). Sensitivity analysis showed that the high coefficient of variation in group 5 can be explained almost all by the variability observed in Lab B. Coefficient of repeatability of ddPCR was always smaller than RT-qPCR for all level of disease showing a slightly better precision. Our results showed that ddPCR has a good agreement with RT-qPCR and it is more precise to quantify BCR-ABL1 transcript levels, particularly for MR 4 and MR 4.5. Thus, ddPCR may be valuable in diagnostic routine. Disclosures Fava: Novartis: Honoraria; BMS: Honoraria; Pfizer: Honoraria; Incyte: Honoraria. Martino:Bio-Rad: Employment. Saglio:Ariad: Consultancy; Incyte: Consultancy; Pfizer: Consultancy; Jansen: Consultancy; Celgene: Consultancy; Novartis: Consultancy; BMS: Consultancy. Martinelli:Roche: Consultancy; BMS: Consultancy; Novartis: Consultancy; ARIAD: Consultancy; Pfizer: Consultancy. Pane:Novartis: Membership on an entity's Board of Directors or advisory committees, Other: research founding; Janssen: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees. Cilloni:Novartis: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees.

The incidence of cancer, including myeloproliferative neoplasms (MPNs), is projected to increase significantly due to the growing proportion of people aged > 65 years. These older individuals are a heterogeneous population in terms of fitness, comorbidity, and psychological reserve. Therefore, age per se does not always provide an accurate indication of condition in patients with cancer. Frailty has been proposed as an alternative measure of vulnerability that might better indicate which patients can tolerate standard cancer treatment and those who may benefit from treatment adjustment. A number of methods can be used to assess frailty in older patients with hematological malignancies, including the Cardiovascular Health Study Frailty Screening Measure, the FRAIL (Fatigue, Resistance, Ambulation, Illnesses, and Loss of weight) questionnaire, the Clinical Frailty Scale (CFS), and the Gérontopôle Frailty Screening Tool. In addition to physical frailty, comorbidity and quality of life should also be included in the assessment. Prior to the introduction of tyrosine kinase inhibitors (TKIs), age was considered a marker of poor prognosis in patients with MPNs. In contrast, data show that age is not necessarily a contraindication for TKI use. In CML, the efficacy of TKIs has been shown to be independent of age. The JAK1/2 inhibitor ruxolitinib also seems to be effective across a range of patient ages. Available data suggest that chronological age itself should not necessarily be a contraindication for many new therapies in patients with MPNs, and that frailty does provide a better measure of vulnerability. There is a need for specific methods to assess frailty in patients with MPNs, particularly the context of effective new treatment options, such as TKIs and ruxolitinib.

Scarce information is available on the use of ponatinib as second-line treatment in chronic phase chronic myeloid leukemia (CP-CML) patients resistant and/or intolerant to prior tyrosine kinase inhibitor (TKI) therapy. We collected data from 29 CML patients, with a median age of 54 years (range 32–72). Eleven patients had received dasatinib, 15 patients received nilotinib, and 3 patients received imatinib as first-line treatment. Forty-five percent of patients started ponatinib for secondary resistance, 38% for primary resistance, 7% for severe intolerance associated to a molecular warning, 7% due to the presence of a T315I mutation, and 3% for severe intolerance. Ponatinib was started at a dose of 45 mg in 60% of patients, 30 mg in 38%, and 15 mg in 2% of patients. Overall, at a median follow-up of 12 months, 85% of treated patients improved the level of response as compared to baseline, with 10 patients achieving a deep molecular response (MR4-4.5). No thrombotic events were recorded. The dose was reduced during treatment in 2 patients due to intolerance and in 8 patients in order to reduce the cardiovascular risk. Ponatinib seems a valid second-line treatment option for chronic phase CML, in particular for patients who failed a front-line second-generation TKI due to BCR-ABL-independent mechanisms of resistance.

In spite of the proven efficacy of the tyrosine kinase inhibitor (TKI), imatinib, in chronic myeloid leukemia (CML), many patients develop intolerance and discontinue therapy in the long-term. Second-generation TKIs (dasatinib, nilotinib, bosutinib) and the third-generation TKI, ponatinib, have added opportunities but also complexity in the settings of CML treatment.Different definitions of intolerance have been used through several clinical trials, making the published data non homogenous. In most cases, only the severity of acute adverse events (AEs), graded by conventional scales such as Common Terminology Criteria for Adverse Events, was reported. Limited attention to long-term events or more in general, to the impact of AEs on patient quality of life (QoL), remains a problem. Ponatinib is active against all BCR-ABL1 mutants, including T315I, and is widely used to treat patients who developed resistance to other TKIs in any CML phase; however, only limited data is available on the possible role of ponatinib for intolerant patients.We review the different definitions of intolerance used in sponsored trials and in clinical practice, and we discuss how such definitions impact on the management of AEs. We summarize how to evaluate QoL during treatment with TKIs and how to include ponatinib among possible option for intolerant patients.

Background: Ponatinib is effective as salvage treatment for chronic phase (CP) Ph+ chronic myeloid leukemia (CML) patients resistant or intolerant to prior TKIs. Based on the concern for an unfavourable cardiovascular toxicity profile, a dose reduction to 15 mg daily is currently recommended in CP patients after the achievement of treatment milestones. As more flexible approaches with TKIs dosage are increasingly adopted in clinical practice, identifying specific profiles of patients eligible for different treatment strategies, in order to improve the benefit/risk ratio, would be of particular interest. Aims: To update previous observations in an extended cohort of CML patients, resistant or intolerant to prior TKIs, describing the efficacy and toxicity of two different ponatinib schedules (de-escalated vs 15 mg starting dose). Secondly, to investigate whether specific subsets of CML patients were managed more successfully with one strategy. Methods: A retrospective analysis of CML-CP patients treated with ponatinib 15 mg, as starting or de-escalated dose has been performed. No pre-specified criteria to switch to ponatinib, to reduce or to start therapy with a lower dose were indicated. Cytogenetic and molecular responses were evaluated according to the ELN2013 recommendations. Toxicities under ponatinib treatment leading to transient or definitive discontinuation were recorded. Results: 68 patients were included in this analysis. Median age at ponatinib start was 57 years (range: 28-87). The median time from CML diagnosis to ponatinib treatment was 4.6 years (range: 0.4-19). Most patients (70.6%) were treated with imatinib as frontline treatment. 30/68 patients (44%) received ponatinib as 4th or subsequent line of therapy. ABL1 mutations were detected in 18 (26.5%) patients (being 44% of them positive for the T315I mutation). 50/68 (73.5%) of cases had less than MR2 at the time of ponatinib initiation, with one third exhibiting primary refractoriness to all prior treatments. Resistance to prior TKIs was the reason for switch in 85% of patients treated with higher doses of ponatinib, while 13/26 patients starting with 15 mg were purely intolerant or intolerant and resistant (p= 0.001). No other significant differences between the two groups were identified. MR2, MR3 and MR4/MR4.5 rates were 78.6%, 59.6% and 28.6% in 42 patients treated with the "de-escalated" approach, respectively. First step of dose reduction was decided after a median time of 3.1 months, with a subsequent decrease to 15 mg after a median of 10 months. Dose modifications were guided mostly by adverse events (73%) and, less frequently, to prevent toxicity and/or following response attainment (27%). Median duration of treatment was 27 months (range: 2-81), with 5/42 patients discontinuing ponatinib (1 cerebrovascular accident, 2 severe hematologic toxicities, two cases of resistance/progression). 4 deaths were registered, three after blast crisis and one for a fatal cardiovascular event. 26 patients started ponatinib 15 mg daily, with a median duration of treatment was 15 months (range: 2-58). MR2 was obtained in 77%, MR3 in 69.3% and MR4 in 46.2% of cases, respectively. MR3 or deeper responses were maintained in 80% of patients; 7/26 lost their best acquired response, with subsequent dose escalation to higher than 15 mg in 5/26 patients. Treatment discontinuation was necessary in 3 cases (1 coronary vasospasm-induced acute coronary syndrome, 2 muscle skeletal pain). Of note, patients with ABL mutations gained benefit only from the "de-escalated" approach, with response improvements in 10/14 of cases vs 0/4 in the "low dose" group. Similarly, a higher rate of at least a MR2 was obtained in primary refractory patients treated ab initio with higher doses of ponatinib (57.1 % vs 14.3 %). However, focusing only on pure intolerant patients, 15 mg starting dose was very effective, with all patients achieving at least a MR3 or deeper response. Summary/Conclusion: With the limits of the retrospective nature and small sample size, these data suggest that different dose strategies could be applied to specific subsets of CP-CML patients. While mutations or refractoriness to previous treatments should address towards a "debulking approach" with 45 or 30 mg ponatinib dose, intolerant or "low level resistance" cases could benefit from lower starting dose. Further investigation in larger prospective trials is warranted. Disclosures Castagnetti: Incyte: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Bristol Meyers Squibb: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Gugliotta:Bristol-Myers Squibb: Honoraria; Incyte: Honoraria; Novartis: Honoraria; Pfizer: Honoraria. Abruzzese:Ariad: Consultancy; BMS: Consultancy; Novartis: Consultancy; Pfizer: Consultancy. Breccia:Pfizer: Honoraria; BMS: Honoraria; Novartis: Honoraria; Incyte: Honoraria. Levato:Novartis: Other: Advisory board. Pane:AMGEN: Speakers Bureau; BMS: Speakers Bureau; Novartis: Research Funding, Speakers Bureau.

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Chronic myeloid leukemia (CML) patients in sustained “deep molecular response” may stop TKI treatment without disease recurrence; however, half of them lose molecular response shortly after TKI withdrawing. Well-defined eligibility criteria to predict a safe discontinuation up-front are still missing. Relapse is probably due to residual quiescent TKI-resistant leukemic stem cells (LSCs) supposedly transcriptionally low/silent and not easily detectable by BCR-ABL1 qRT-PCR. Bone marrow Ph+ CML CD34+/CD38− LSCs were found to specifically co-express CD26 (dipeptidylpeptidase-IV). We explored feasibility of detecting and quantifying CD26+ LSCs by flow cytometry in peripheral blood (PB). Over 400 CML patients (at diagnosis and during/after therapy) entered this cross-sectional study in which CD26 expression was evaluated by a standardized multiparametric flow cytometry analysis on PB CD45+/CD34+/CD38− stem cell population. All 120 CP-CML patients at diagnosis showed measurable PB CD26+ LSCs (median 19.20/μL, range 0.27–698.6). PB CD26+ LSCs were also detectable in 169/236 (71.6%) CP-CML patients in first-line TKI treatment (median 0.014 cells/μL; range 0.0012–0.66) and in 74/112 (66%), additional patients studied on treatment-free remission (TFR) (median 0.015/μL; range 0.006–0.76). Notably, no correlation between BCR-ABL/ABLIS ratio and number of residual LSCs was found both in patients on or off TKIs. This is the first evidence that “circulating” CML LSCs persist in the majority of CML patients in molecular response while on TKI treatment and even after TKI discontinuation. Prospective studies evaluating the dynamics of PB CD26+ LSCs during TKI treatment and the role of a “stem cell response” threshold to achieve and maintain TFR are ongoing.

The primary objective of this study was to investigate whether the presence of comorbidities was associated with a lower health-related quality of life (HRQOL) in elderly patients with chronic myeloid leukemia (CML). A sample of 174 CML patients aged 60 years or above was analyzed. HRQOL was assessed with the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). A number of pre-selected sociodemographic and disease-related factors were considered as potential confounding factors for the association between comorbidity and HRQOL. Mean age of the 174 patients analyzed was 70 years (range 60–87 years) and 55 % were male. Overall, 111 patients (64 %) reported at least one comorbidity. Analysis stratified by age group category showed a greater proportion of patients with comorbidities in the older sub-group population (≥70 years) compared to younger patients (60 to 69 years). Differences in HRQOL outcomes between patients with no comorbidity at all and those with two or more comorbid conditions were at least twice the magnitude of a clinically meaningful difference in all the physical and mental health scales of the SF-36. In multivariate analysis, after adjusting for key confounding factors, the following scales were significantly lower in those with comorbidity: general health (p