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Background: Systemic sclerosis is associated with an increased incidence of malignancies, in particular solid neoplasms. Hematological cancers have been also observed in autoimmune diseases, though rarely present with lung involvement. The latter may be misdiagnosed in systemic sclerosis patients, due to the frequent concomitant interstitial lung disease. Case description: Here, we present the case of a 63-year-old man affected by systemic sclerosis presenting with an atypical lung imaging and splenomegaly, who was diagnosed with splenic marginal zone lymphoma, thus raising the suspicion of lung secondarism. We discuss the diagnostic challenge of differential diagnosis in interstitial lung presentation and briefly review the available literature on this topic. Conclusion: Several reports have demonstrated an increased risk of malignancy in patients with systemic sclerosis. Still, the lack of concretely defined guidelines for systemic sclerosis, along with systemic sclerosis multifaceted organ involvement at presentation, may challenge diagnosis and management. Here, we remark the importance of clinical work-up and a multidisciplinary approach in systemic sclerosis, to early detect and treat concomitant hematological malignancies, especially during the first years of the disease.

The presence of peripheral blasts (PB) is a negative prognostic factor in patients with primary and secondary myelofibrosis (MF) and PB ≥4% was associated with a particularly unfavorable prognosis. Ruxolitinib (RUX) is the JAK1/2 inhibitor most used for treatment of MF-related splenomegaly and symptoms. Its role has not been assessed in correlation with PB.In 794 chronic-phase MF patients treated with RUX, we evaluated the impact of baseline percentage of PB on response (spleen and symptoms responses) and outcome (RUX discontinuation-free, leukemia-free, and overall survival). Three subgroups were compared: PB-0 (no PB, 61.3%), PB-4 (PB 1%-4%, 33.5%), and PB-9 (PB 5%-9%, 5.2%).At 3 and 6 months, spleen responses were less frequently achieved by PB-4 (P = .001) and PB-9 (P = .004) compared to PB-0 patients. RUX discontinuation-free, leukemia-free, and overall survival were also worse for PB-4 and PB-9 patients (P = .001, P = .002, and P.001, respectively).Personalized approaches beyond RUX monotherapy may be useful in PB-4 and particularly in PB-9 patients.

In 816 patients with 2016 World Health Organization-defined polycythemia vera (PV) enrolled in a multicenter retrospective study, we investigated the predictive value of Charlson comorbidity index (CCI) and body mass index (BMI) on thrombosis, progression to post-PV myelofibrosis (PPV-MF) and survival. Patients were subgrouped according to CCI=0 (58.1%, no comorbidities) or CCI≥1 (41.9%) and according to normal/underweight (BMI&nbsp

Comorbidities defined by the Charlson comorbidity index (CCI) and body mass index (BMI) are significantly associated with outcome in patients who receive continuous treatment with tyrosine kinase inhibitors. We evaluated the impact of CCI and BMI on responses, drug-related toxicities, and outcome in a cohort of 402 patients with myelofibrosis (MF) treated with ruxolitinib in 23 European Hematology Centers. Comorbidities were evaluable in all 402 patients. A higher (≥ 3) CCI did not correlate with a lower spleen reduction at any time (p = 0.68) or symptoms' response (p = 0.11), but influenced the onset of anemia during the first 3months of treatment and later (p = 0.02 and p = 0.03, respectively) in patients without anemia baseline. BMI was evaluable in 380 patients and did not correlate with differences in spleen and symptoms response (p = 0.57 and p = 0.49, respectively). A higher CCI and a lower BMI correlated also with a reduced overall survival (p

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.

Complex karyotype (CK) at chronic lymphocytic leukemia (CLL) diagnosis is a negative biomarker of adverse outcome. Since the impact of CK and its subtypes, namely type-2 CK (CK with major structural abnormalities) or high-CK (CK with ≥5 chromosome abnormalities), on the risk of developing Richter syndrome (RS) is unknown, we carried out a multicenter real-life retrospective study to test its prognostic impact. Among 540 CLL patients, 107 harbored a CK at CLL diagnosis, 78 were classified as CK2 and 52 as high-CK. Twenty-eight patients developed RS during a median follow-up of 6.7 years. At the time of CLL diagnosis, CK2 and high-CK were more common and predicted the highest risk of RS transformation, together with advanced Binet stage, unmutated (U)-IGHV, 11q-, and TP53 abnormalities. We integrated these variables into a hierarchical model: high-CK and/or CK2 patients showed a 10-year time to RS (TTRS) of 31%; U-IGHV/11q- /TP53 abnormalities/Binet stage B-C patients had a 10-year TTRS of 12%; mutated (M)-IGHV without CK and TP53 disruption a 10-year TTRS of 3% (P

Background Complex karyotype (CK) is a heterogeneous category with a negative impact in chronic lymphocytic leukaemia (CLL). Our group has recently reported that CK patients with major structural abnormalities (i.e. CK2) are characterised by a worse prognosis, as compared to other lesions within CK(CK1). Methods We performed a multicentre retrospective study to test whether the combination of CK subtypes with IGHV status could be a relevant prognostic and predictive tool. Results Among 522 patients 13% harboured CK2, 41% CK1 and/or U-IGHV (U-CK1) and 46% M-IGHV without any CK subtypes (M-noCK). After a median follow-up of 5.8 years, CK2 patients had the shortest TTFT (5-year TTFT 31%, 39 and 81%, p

BACKGROUND: After ruxolitinib discontinuation, the outcome of patients with myelofibrosis (MF) is poor with scarce therapeutic possibilities. METHODS: The authors performed a subanalysis of an observational, retrospective study (RUX-MF) that included 703 MF patients treated with ruxolitinib to investigate 1) the frequency and reasons for ruxolitinib rechallenge, 2) its therapeutic effects, and 3) its impact on overall survival. RESULTS: A total of 219 patients (31.2%) discontinued ruxolitinib for ≥14 days and survived for ≥30 days. In 60 patients (27.4%), ruxolitinib was rechallenged for ≥14 days (RUX-again patients), whereas 159 patients (72.6%) discontinued it permanently (RUX-stop patients). The baseline characteristics of the 2 cohorts were comparable, but discontinuation due to a lack/loss of spleen response was lower in RUX-again patients (P =.004). In comparison with the disease status at the first ruxolitinib stop, at its restart, there was a significant increase in patients with large splenomegaly (P 10 mg twice daily predicted better spleen (P =.05) and symptom improvements (P =.02), the reasons for/duration of ruxolitinib discontinuation and the use of other therapies before rechallenge were not associated with rechallenge efficacy. At 1 and 2 years, 33.3% and 48.3% of RUX-again patients, respectively, had permanently discontinued ruxolitinib. The median overall survival was 27.9 months, and it was significantly longer for RUX-again patients (P =.004). CONCLUSIONS: Ruxolitinib rechallenge was mainly used in intolerant patients; there were clinical improvements and a possible survival advantage in many cases, but there was a substantial rate of permanent discontinuation. Ruxolitinib rechallenge should be balanced against newer therapeutic possibilities.

In chronic-phase chronic myeloid leukemia (CML), tyrosine kinase inhibitors (TKIs) are the standard of care, and treatment-free remission (TFR) following the achievement of a stable deep molecular response (DMR) has become, alongside survival, a primary goal for virtually all patients. The GIMEMA CML working party recently suggested that the possibility of achieving TFR cannot be denied to any patient, and proposed specific treatment policies according to the patient’s age and risk. However, other international recommendations (including 2020 ELN recommendations) are more focused on survival and provide less detailed suggestions on how to choose first and subsequent lines of treatment. Consequently, some grey areas remain. After literature review, a panel of Italian experts discussed the following controversial issues: (1) early prediction of DMR and TFR: female sex, non-high disease risk score, e14a2 transcript and early MR achievement have been associated with stable DMR, but the lack of these criteria is not sufficient to exclude any patient from TFR; (2) criteria for first and subsequent line therapy choice: a number of patient and drug characteristics have been proposed to make a personalized decision; (3) monitoring of residual disease after discontinuation: after the first 6 months, the frequency of molecular tests can be reduced based on MR4.5 persistence and short turnaround time; (4) prognosis of TFR: therapy and DMR duration are important to predict TFR; although immunological control of CML plays a role, no immunological predictive phenotype is currently available. This guidance is intended as a practical tool to support physicians in decision making.

In this article, we carry out an overview on the management options available for chronic lymphocytic leukemia (CLL) patients and discuss possible treatment decisions, taking into account the issue of sustainability and availability. Targeted agents have shown to be superior compared with chemoimmunotherapy (CIT) in terms of progression-free survival in high-risk CLL. In the majority of studies, however, continuous treatment was compared with fixed-duration CIT and no overall survival or progression-free survival-2 (time from randomization to second progression or death) advantage could be documented. Meanwhile, a substantial financial burden on both patients and payers has raised issues about affordability and adherence to treatment. Therefore, value-based pricing of new drugs has been used to set up price negotiation policies in several countries, and fixed-duration therapy has shown to be less costly than continuous treatment. Thus, CIT continues to have a role in the treatment of CLL patients with a favorable genetic profile, that is, with a mutated IGHV gene profile and a wild-type TP53. Targeted treatment represents the preferred choice in patients with an unmutated IGHV gene configuration and/or a TP53 disruption, provided that adherence to treatment is guaranteed and bearing in mind that should costly drugs not be available for frontline treatment, new agents can be very effective as first salvage treatment.

In a series of 349 patients with chronic lymphocytic leukaemia (CLL), we found lower levels of signalling lymphocytic activation molecule family member 1 (SLAMF1) expression in cases with highly complex karyotypes, as defined by the presence of five or more chromosomal abnormalities (CK5; P < 0·001) and with major chromosomal structural abnormalities (P < 0·001). SLAMF1 downregulation was significantly associated with advanced Binet Stage (P = 0·001), CD38 positivity (P < 0·001), high β2 -microglobulin levels (P < 0·001), immunoglobulin heavy chain variable region gene (IGHV) unmutated status (P < 0·001), 11q deletion (P < 0·001), tumour protein p53 (TP53) disruption (P = 0·011) and higher risk CLL International Prognostic Index categories (P < 0·001). Multivariate analysis showed that downregulated SLAMF1 levels had independent negative prognostic impact on time-to-first treatment (P < 0·001) and overall survival (P < 0·001).

Multiple myeloma (MM) is a genetically heterogeneous disease, in which the process of tumorigenesis begins and progresses through the appearance and accumulation of a tangle of genomic aberrations. Several are the mechanisms of DNA damage in MM, varying from single nucleotide substitutions to complex genomic events. The timing of appearance of aberrations is well studied due to the natural history of the disease, that usually progress from pre-malignant to malignant phase. Different kinds of aberrations carry different prognostic significance and have been associated with drug resistance in some studies. Certain genetic events are well known to be associated with prognosis and are incorporated in risk evaluation in MM at diagnosis in the revised International Scoring System (R-ISS). The significance of some other aberrations needs to be further explained. Since now, few phase 3 randomized trials included analysis on patient’s outcomes according to genetic risk, and further studies are needed to obtain useful data to stratify the choice of initial and subsequent treatment in MM.

No abstract available

The impact of ruxolitinib therapy on evolution to blast phase (BP) in patients with myelofibrosis (MF) is still uncertain. In 589 MF patients treated with ruxolitinib, we investigated incidence and risk factors for BP and we described outcome according to disease characteristics and treatment strategy. After a median follow-up from ruxolitinib start of 3 years (range 0.1-7.6), 65 (11%) patients transformed to BP during (93.8%) or after treatment. BP incidence rate was 3.7 per 100 patient-years, comparably in primary and secondary MF (PMF/SMF) but significantly lower in intermediate-1 risk patients (2.3 vs 5.6 per 100 patient-years in intermediate-2/high-risk patients, P

Ruxolitinib (RUX), the first JAK1/JAK2 inhibitor approved for myelofibrosis (MF) therapy, has recently been associated with the occurrence of second primary malignancies (SPMs), mainly lymphomas and non-melanoma skin cancers (NMSCs). We analyzed the incidence, risk factors and outcome of SPMs in 700 MF patients treated with RUX in a real-world context. Median follow-up from starting RUX was 2·9years. Overall, 80 (11·4%) patients developed 87 SPMs after RUX start. NMSCs were the most common SPMs (50·6% of the cases). Multivariate analysis demonstrated that male sex [hazard ratio (HR): 2·37, 95% confidence interval (95%CI): 1·22–4·60, P=0·01] and thrombocytosis>400×109/l at RUX start (HR:1·98, 95%CI: 1·10–4·60, P=0·02) were associated with increased risk for SPMs. Risk factors for NMSC alone were male sex (HR: 3·14, 95%CI: 1·24–7·92, P=0·02) and duration of hydroxycarbamide and RUX therapy>5years (HR: 3·20, 95%CI: 1·17–8·75, P=0·02 and HR: 2·93, 95%CI: 1·39–6·17, P=0·005 respectively). In SPMs excluding NMSCs, male sex (HR: 2·41, 95%CI: 1·11–5·25, P=0·03), platelet>400×109/l (HR: 3·30, 95%CI: 1·67–6·50, P=0·001) and previous arterial thromboses (HR: 3·47, 95%CI: 1·48–8·14, P=0·004) were shown to be associated with higher risk of SPMs. While it is reassuring that no aggressive lymphoma was documented, active skin surveillance is recommended in all patients and particularly after prolonged hydroxycaramide therapy; oncological screening should be triggered by thrombocytosis and arterial thrombosis, particularly in males.

The complex karyotype (CK) is an established negative prognostic marker in a number of haematological malignancies. After the introduction of effective mitogens, a growing body of evidence has suggested that the presence of 3 or more aberrations by conventional banding analysis (CBA) is associated with an unfavorable outcome in chronic lymphocytic leukemia (CLL). Thus, the importance of CBA was recognized by the 2018 guidelines of the International Workshop on CLL, which proposed the introduction of CBA in clinical trials to validate the value of karyotype aberrations. Indeed, a number of observational studies showed that cytogenetic aberrations and, particularly, the CK may have a negative independent impact on objective outcome measures (i.e. time to first treatment, progression free survival, time to chemorefractoriness and overall survival) both in patients treated with chemoimmunotherapy and, possibly, in patients receiving novel mechanism-based treatment. Here, we set out to present the scientific evidence supporting the significance of CK as a prognostic marker in CLL and to discuss the biological basis showing that the CK is a consequence of genomic instability.

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 (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.

Introduction: Ruxolitinib (Rux) has been recently approved as second-line therapy in patients (pts) with Polycythemia Vera (PV) resistant/intolerant to hydroxyurea (HU). Median age of PV pts enrolled in the pivotal Response trials was around 60 yrs; at present, no data is reported on the use of Rux in elderly pts. Aims: In a real-world cohort of PV pts treated with Rux, we investigated whether the efficacy and safety of Rux were comparable in pts who initiated therapy when aged ≥75 years compared with younger pts. Methods: After IRB approval, clinical/laboratory data of 934 WHO2016-defined PV pts followed in 29 Hematology Centers were retrospectively collected. Of them, 168 (17.9%) were considered resistant/intolerant to HU at any time during follow-up by responsible physician and shifted to Rux as second-line therapy. Results: Among the 168 pts treated with Rux, 42 (25%, median age 78.2 years) were aged ≥75 yrs at Rux start, 74 (44%, median age 67.7) were aged 60-74 and 52 (31%, median age 53) were No significant differences were observed between the 3 groups, apart from a lower need for phlebotomies in pts aged ≥75 yrs and lower presence of palpable spleen in older pts (age ≥60), that more frequently switched to Rux due to HU intolerance (Table 1). Median duration of HU treatment was 41.0 months (IQR 14.6 - 85.8), with a trend for a longer median treatment duration in pts aged ≥75 [61.0 months (IQR 21.5 - 89.6) vs 35.9 months (IQR 13.4 - 79.6), p=0.04]. Rux starting dose was similar across age groups; however, more elderly pts underwent Rux dose reductions during follow-up (45.2% in pts aged ≥75 vs 28.6% in younger pts, p=0.04). Responses during Rux therapy are reported in Table 2, with no significant differences between the 3 groups at any time. In the overall cohort, response on PV-related symptoms at 6 and 12 months was significantly higher in pts who switched to Rux because of HU intolerance; however, this difference was not observed in pts aged ≥75 yrs. As to the most common hematologic Rux-related toxicities, grade 3-4 anemia and thrombocytopenia were observed in only 2 (1.2%) and 5 (3%) pts, with no difference across age groups (p=0.45 and p=0.18). However, any grade anemia and thrombocytopenia during Rux were more frequently observed in pts aged ≥75 (68.3% vs 51.7% of anemia, p=0.06 and 12.2% vs 3.5% of thrombocytopenia in younger pts, p=0.04). Nineteen and 4 pts experienced infectious and thrombotic complications during Rux with incidence rates of 0.59 and 0.12 per 100 patient-months, respectively, comparably in younger and older (≥75) pts (p=0.75 and p=0.29, respectively). Notably, 6 infections were herpes simplex/zoster virus, comparably distributed between the 3 groups (p=0.60). Permanent Rux discontinuation was needed in 14 pts (8.3%) after a median Rux exposure of 7.8 months (IQR 4.6 - 17.6) (incidence: 0.41 per 100 pts/months). Discontinuation was comparable between age groups, with Rux stop in 4 pts aged ≥75 yrs and 10 younger pts (2.4% vs 5.2% at 8 months, log-rank p=0.75). At last follow-up, 2 pts had died (1 from 2 nd neoplasia after 19.1 months from Rux start and 1 from acute leukemia after 3.3 years), both pts aged 60-74 yrs. Conclusions. In this real-world analysis, use of Rux in HU resistant/intolerant elderly PV pts was effective and safe despite the more frequent need for dose reductions. Older age should not discourage Rux therapy, but stricter hematological monitoring may be suggested. Figure 1 Figure 1. Disclosures Latagliata: BMS Cellgene: Honoraria; Pfizer: Honoraria; Novartis: Honoraria. Breccia: Pfizer: Honoraria; Incyte: Honoraria; Bristol Myers Squibb/Celgene: Honoraria; Abbvie: Honoraria; Novartis: Honoraria. Bonifacio: Amgen: Honoraria; Bristol Myers Squibb: Honoraria; Novartis: Honoraria; Pfizer: Honoraria. Cavo: Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Consultancy, Honoraria; GlaxoSmithKline: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel Accommodations, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Speakers Bureau; Bristol-Myers Squib: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Palandri: AOP: Membership on an entity's Board of Directors or advisory committees; Sierra Oncology: Membership on an entity's Board of Directors or advisory committees; CTI: Consultancy; Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees.

Background: The presence of peripheral blasts (PB) is a negative prognostic factor in patients (pts) with primary and secondary myelofibrosis (PMF/SMF) and PB ≥4% was associated with a particularly unfavorable prognosis (Masarova L et al, Cancer 2020). Ruxolitinib (RUX) is the JAK1/2 inhibitor most used for treatment of MF-related splenomegaly and symptoms. Its role has not been assessed in correlation with PB. Aims: To evaluate the impact of PB percentage on RUX efficacy and prognosis Methods: After IRB approval, the "RUX-MF" retrospective study collected 804 RUX-treated chronic-phase (CP, defined as PB Comparisons of quantitative variables between the 3 groups were carried out by Kruskal-Wallis and Dunn's tests while association between categorical variables was tested by the χ2 test. Variables significantly associated to RUX stop/leukemic transformation (LT)/overall survival (OS) in univariate analysis (Log-rank test) were considered for multivariable analyses, carried out using the Cox regression model, with evaluation of the model's performance in terms of goodness of fit. Results: Pts were categorized according to PB at RUX start: PB-0 (no PB; n. 487, 61.3%), PB-5 (PB 1-5%; n. 283, 35.8%), and PB-9 (PB 6-9%; n. 24, 2.9%). Pts characteristics at RUX start were: median age 68.1y (24-89); males 58.1%; PMF 52.5%; JAK2, CALR and MPL mutated: 80.5%, 13.1% and 2% (4.4% triple negative), high DIPSS: 7.6%; PLT25 x10 9/l: 10.8%/16.4%; spleen length ≥10 cm: 47.8%, TSS ≥20: 60.6%; ≥1/≥2 high-risk mutation (HMR): 69/18 out of 167 evaluable (41.3%/10.8%); fibrosis grade ≥2: 77.9%; starting/cumulative RUX dose ≥15 mg BID: 61.4%/52.6%. Higher PB count was associated to high DIPSS risk (PB-0: 1.9%, PB-5: 16.2%, PB-9: 21.7%, p At 3 and 6 mos, 26.9% and 30.4% of evaluable pts achieved a SR, while 59.7% and 68.1% were in SyR, respectively. At 3 mos, SR (PB-0: 31.8%, PB-5: 20.6%, PB-9: 10%, p=0.001) and SyR (PB-0: 62.9%, PB-5: 55.5%, PB-9: 36.8%, p=0.02) were less frequently achieved by PB-5 and PB-9 pts compared to PB-0 pts. This association remained significant for SR at 6 mos (PB-0: 35%, PB-5: 23.9%, PB-9: 14.3%, p=0.006) and for both SR (p=0.003) and SyR (p=0.01) at any time. After a median RUX exposure of 1.5 y (0.1-8.9), 491 (61.8%) pts stopped RUX, 110 (13.9%) had a LT and 365 (46%) died. In univariate analysis, at 2y PB-9 pts had higher rates of RUX stop (73.9% vs 40.8% and 34.3% in PB-5 and PB-0 pts, log-rank p In multivariable analysis, PB-9 pts confirmed their association with: 1) RUX stop (HR 3.74, 95%CI 1.51-3.70, p20 (HR 1.66, 95%CI 1.05-2.61, p=0.03), and HMR≥2 (HR 2.69, 95%CI 1.26-4.47, p=0.007); 2) LT (HR 3.71, 95%CI 1.71-8.04, p Conclusions: CP-MF pts with PB>5% have a worse response to RUX and a worse outcome. Personalized approaches beyond RUX monotherapy may be useful in this context. Further clinical trials evaluating combination strategies and new drugs are required. Figure 1 Figure 1. Disclosures Palandri: Novartis: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; AOP: Membership on an entity's Board of Directors or advisory committees; Sierra Oncology: Membership on an entity's Board of Directors or advisory committees; CTI: Consultancy. Abruzzese: Bristol Myers Squibb: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria. Iurlo: Bristol Myers Squibb: Speakers Bureau; Pfizer: Speakers Bureau; Novartis: Speakers Bureau; Incyte: Speakers Bureau. Bonifacio: Bristol Myers Squibb: Honoraria; Novartis: Honoraria; Pfizer: Honoraria; Amgen: Honoraria. Cuneo: AbbVie: Consultancy, Speakers Bureau; AstraZeneca: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Gilead: Consultancy, Speakers Bureau. Pane: AbbVie; Amgen; Novartis: Other: Travel, accommodation, expenses; Novartis Pharma SAS;: Research Funding; AbbVie; Amgen; Novartis, GSK , Incyte: Consultancy; AbbVie; Amgen; Novartis, GSK, Incyte: Speakers Bureau. Lemoli: Celgene: Other: Support for attending meetings and/or travel; Jazz, Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie, Daiichi Sankyo, Servier: Honoraria, Speakers Bureau. Cavo: Bristol-Myers Squib: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Speakers Bureau; Adaptive Biotechnologies: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel Accommodations, Speakers Bureau; GlaxoSmithKline: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Breccia: Novartis: Honoraria; Pfizer: Honoraria; Incyte: Honoraria; Bristol Myers Squibb/Celgene: Honoraria; Abbvie: Honoraria.

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Introduction: Hydroxyurea (HU) is the most used cytoreductive therapy (tx) for patients (pts) with polycythemia vera (PV). However, many pts may have suboptimal responses (SubOR) and/or toxicity (TOX) to HU. After HU, Ruxolitinib (RUX) may achieve hematocrit (HCT) and spleen reductions, but other tx are also available, mainly busulfan (BUS) and interferons (IFN). Aims: In a large cohort of PV pts, we investigated if: 1) type of SubOR to HU influenced subsequent tx strategy; 2) differential tx had an impact on overall survival (OS). Methods: After IRB approval, clinical/laboratory data of 2016 WHO-defined PV pts from 21 European Hematology Centers were retrospectively collected. SubOR included ≥1 of the following criteria after ≥3 mos of HU: WBC/PLT count >10/400 x109/l, need for phlebotomies (PHL); splenomegaly and/or symptoms persistence/occurrence (Barosi G et al, Blood 2009). Only pts with stable SubOR were included in this analysis. Since a complete response was never achieved, the index date (ID) was set at 3 mos from HU start in all pts (Barosi G et al, BJH 2009). OS was calculated from the ID by Cox analysis with age>80, adjusted with left truncation from PV diagnosis. Results: At data cut-off date (June 2020), 808 PV pts were collected; 688 received HU. Among the 452 (65.7%) pts who presented a stable SubOR to HU, 41 did not receive any tx for PV due to early death or progression to BP/MF and were excluded from this analysis. Baseline characteristics of the 411 evaluable pts were: median age: 65 yrs (21- 87); males: 54%; median (range) WBC/PLT count, x109/l: 10 (1.1-38)/465 (139-1209); median Hb (g/dl)/HCT (%): 18.6/56 (males); 17.6/54 (females); palpable splenomegaly: 38%; symptoms: 80.5%; pruritus: 42%. A previous thrombosis occurred in 104 (25.3%) pts. At least one cardiovascular risk factor (CVRF: smoke, diabetes, hypertension, dyslipidemia and overweight) was present in 325 pts (79.1%). After a median follow-up of 4.8 yrs (0.5-27.6) from HU start, 104 (25.3%) switched to RUX (HU-RUX), 18 (4.4%) switched to another agent (HU-other, including IFN, BUS, PHL only), and 289 (70.3%) continued HU (HU-alone). Pts with baseline palpable spleen (p While 331 (80.5%) pts had a stable SubOR without TOX, 80 (19.5%) had also TOX. Notably, pts with only SubOR more frequently continued HU (p In 45.5% of pts, the SubOR was related only to uncontrolled WBC/PLT/HCT, while 16.1% of pts had an optimal hematological control but presented spleen/symptoms; the remaining 38.4% of pts had both uncontrolled myeloproliferation and spleen/symptoms. The presence of both uncontrolled myeloproliferation and spleen/symptoms significantly predicted RUX switch (p Investigating the SubOR criteria individually among the HU-alone/other and the HU-RUX groups, we found that uncontrolled leukocytosis and/or thrombocytosis (p After the ID, 31 pts died. HU-RUX pts presented increased OS compared to HU-alone/other pts (p=0.03). Conclusions. This study revealed a high rate of SubOR to HU, possibly also affected by low HU doses, and a lack of urgency to change the tx in these pts, with >70% of pts continuing HU despite the stable SubOR. Particularly, good tolerance to HU, absence of splenomegaly and pruritus, and older age were the main factors against a tx change. Notably, despite HCT>45% is associated with worse outcome (Marchioli R, NEJM 2013), PHL need did not significantly trigger tx change. The better OS in the HU-RUX group is presumably multifactorial and requires further confirmation. Overall, this analysis points out the need to improve HU management and response evaluations, weighing appropriate tx strategies in case of SubOR. Disclosures Palandri: Novartis: Consultancy, Honoraria. Benevolo:Amgen: Honoraria; Celgene: Honoraria; Novartis: Honoraria. Breccia:Bristol-Myers Squibb/Celgene: Consultancy, Honoraria; Abbvie: Consultancy; Incyte: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Cavazzini:Pfize: Honoraria; Novartis: Honoraria; Incyte: Honoraria. Heidel:Celgene: Consultancy; CTI: Consultancy; Novartis: Consultancy, Research Funding. Crugnola:BMS: Honoraria; Janssen: Honoraria; Celgene: Honoraria; Novartis: Honoraria. Pane:Daiichi Sankyo: Consultancy, Other: Travel Expenses; Janssen: Other: Travel Expenses; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Other: travel expenses, Speakers Bureau; Novartis pharma SAS: Consultancy, Other: Travel Expenses, Research Funding, Speakers Bureau; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, Other: Travel Expenses, Speakers Bureau; AbbVie: Consultancy, Other: Travel Expenses, Speakers Bureau. Cuneo:Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astra Zeneca: Honoraria; Roche: 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; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Krampera:Janssen: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Semenzato:Takeda: Honoraria; Roche: Honoraria; Abbvie: Honoraria. Lemoli:Jazz: Consultancy, Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees; Servier: 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; Celgene: Research Funding; BerGenBio ASA: Research Funding; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees. Cavo:Jannsen, BMS, Celgene, Sanofi, GlaxoSmithKline, Takeda, Amgen, Oncopeptides, AbbVie, Karyopharm, Adaptive: Consultancy, Honoraria. Palumbo:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

Introduction: The outcome of patients (pts) with myelofibrosis (MF) who discontinue ruxolitinib (RUX) is poor with scarce therapeutic possibilities (Palandri et al, 2020). However, some evidences suggest that pts may respond to a rechallenge of RUX after drug stop (Gerds et al, 2018). Aims: To investigate in a real-world context: 1) frequency and reasons for rechallenge; 2) therapeutic effects of rechallenge; 3) impact of rechallenge on overall survival (OS) Methods: After IRB approval, a clinical database was created in 20 European Hematology Centers including now retrospective data of 703 MF pts who started RUX from Jan 2011 to Nov 2019. Only chronic phase (CP) pts who stopped RUX for ≥14 days and survived ≥30 days after discontinuation were included. A specific survey collected clinical/laboratory data at RUX stop and at rechallenge, reasons for discontinuation and treatments before rechallenge. OS was estimated from the date of the first/only RUX discontinuation to last contact (log-rank test). Results: A total of 219 CP pts was evaluable for this study. In 60 (27.4%) pts, RUX was re-challenged for ≥14 days after the first discontinuation (RUX-again), while 159 (72.6%) pts discontinued RUX permanently (RUX-stop). The median time from RUX start to stop was of 16.5 and 12.3 mos for RUX-again and RUX-stop pts, respectively (p=0.41). At RUX start, characteristics of RUX-again were: median age 67y (24-88); males 61.7%; PMF 53.3%; median Hb 10.2 g/dl; median PLT/WBC: 249/12.6 x109/l; median RUX starting dose: 15mg BID. Baseline characteristics of RUX-again and RUX-stop pts were comparable. In the 60 RUX-again pts, reasons for discontinuation included loss of/inadequate response (18 pts, 30%) and toxicity (42 pts, 70%). Toxicity included G3-4 thrombocytopenia (38.1%), anemia (26.2%), infections (21.4%), other (14.3%). Conversely, RUX-stop pts discontinued RUX mainly due to loss of/inadequate response (75 pts, 47.2%), while intolerable toxicity occurred in 69 pts (43.4%) (p=0.004) and other causes in 9.4%. At first RUX discontinuation, 35.7% of RUX-again pts presented with large (>10 cm) splenomegaly; median Total Symptoms Score (TSS) was 10 (TSS>20 in 30.4% of pts). The median duration of temporary RUX discontinuation was 2 mos (range 0.5-71.1). During RUX stop, 65% of RUX-again pts did not receive any therapy, 15% received only palliation (steroids, hydroxyurea), while 11.7% switched to investigational agents, 3.3% underwent splenectomy and 5% allogeneic transplantation. Compared to disease status at first RUX stop, at RUX restart there was a significant increase of pts with large splenomegaly and high TSS, while the PLT count was higher and RUX dose significantly lower (Table 1). The median duration of RUX rechallenge was 7.5 mos (0.5-72.7). During the rechallenge, 44.6% and 48.3% pts improved spleen and symptoms, and there was a significant increase in pts with TSS reduction (p=0.01); 8 pts (13.3%) continued RUX with stable/worsening spleen size and improvement in TSS. Conversely, 26.8% and 20% of pts had increase in spleen size and in symptoms, respectively. While Hb levels remained stable, PLT count significantly decreased during rechallenge (p The reasons for temporary discontinuation had no impact on the reduction of spleen/symptoms during rechallenge and on OS. However, comparing RUX-again and RUX-stop pts, RUX-again pts showed a better OS, with a median survival of 41.1 mos and 23.7, respectively in the 2 cohorts (Fig. 1). Conclusions: This real-world study highlights that RUX rechallenge is quite common in CP-MF pts, involving almost 30% of treated pts, particularly when the discontinuation is due to toxicity. The temporary discontinuation, while improving PLT count, generally caused a significant increase in disease burden. After rechallenge, almost 50% of pts achieved clinical responses regardless of reason of first discontinuation. This residual disease control activity, that correlated with improved OS, should be weighed up also given the new therapeutic possibilities available in these pts. Disclosures Palandri: Novartis: Consultancy, Honoraria. Breccia:Abbvie: Consultancy; Bristol-Myers Squibb/Celgene: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Incyte: Consultancy, Honoraria. Benevolo:Amgen: Honoraria; Celgene: Honoraria; Novartis: Honoraria. Cavazzini:Incyte: Honoraria; Pfize: Honoraria; Novartis: Honoraria. Crugnola:Janssen: Honoraria; BMS: Honoraria; Novartis: Honoraria; Celgene: Honoraria. Heidel:CTI: Consultancy; Celgene: Consultancy; Novartis: Consultancy, Research Funding. Pane:Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Other: travel expenses, Speakers Bureau; Daiichi Sankyo: Consultancy, Other: Travel Expenses; Novartis pharma SAS: Consultancy, Other: Travel Expenses, Research Funding, Speakers Bureau; Janssen: Other: Travel Expenses; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, Other: Travel Expenses, Speakers Bureau; AbbVie: Consultancy, Other: Travel Expenses, Speakers Bureau. Cuneo: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; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Krampera:Janssen: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Semenzato:Takeda: Honoraria; Roche: Honoraria; Abbvie: Honoraria. Lemoli:AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz: Consultancy, Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees; Servier: 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; Celgene: Research Funding; BerGenBio ASA: Research Funding. Cavo:Jannsen, BMS, Celgene, Sanofi, GlaxoSmithKline, Takeda, Amgen, Oncopeptides, AbbVie, Karyopharm, Adaptive: Consultancy, Honoraria. Palumbo:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

Introduction Hydroxyurea (HU) is worldwide used in the current clinical practice as first line treatment in high risk patients with Polycythemia Vera (PV). However, its efficacy has been seldom evaluated in the real-life setting. Aims The present study aims to address the role of Complete Peripheral Recovery (CPR) as useful response criteria in PV patients treated with HU in a large cohort of unselected patients. Methods After IRB approval, data of 846 PV patients, revised according to WHO2008/2016 and followed in 21 European Hematology Centers, were retrospectively collected. Definition of CPR during HU treatment included all the following criteria: hematocrit (Ht) level ≤45% (≤3 phlebotomies per year allowed), white blood cells (WBC) count ≤10 x109/l, platelets (PLT) count ≤ 400 x109/l. Spleen size and symptoms were not considered in the definition of CPR. Event-free survival (EFS), considering as event evolution into blast phase (BP) or myelofibrosis (MF) and death from any cause, was calculated from HU start to last contact/event by Cox analysis with age≥70y. Overall survival (OS) was calculated from the start of HU to last contact/death (log-rank p). Results Among the 846 patients of the entire cohort, 724 (85.5%) were treated with HU after a median time from PV diagnosis of 2.6 months [interquartile range (IQR) 0.5 - 19.6]: the main clinical features of these 724 patients at diagnosis are reported in the Table 1. Starting doses of HU, available in 709 patients, were 1000 mg/day in 38 (5.4%). Twenty-five patients were not evaluable for response to HU. Among the remaining 699 patients, 426 (60.9%) achieved a CPR after a median time from HU start of 4.9 months (IQR 2.1 - 15.7) while 273 (39.1%) never achieved a CPR. Among the 426 patients who achieved CPR, 115 (26.9%) needed a treatment period >12 months before obtaining the CPR. The main baseline clinical features of patients achieving or not CPR are reported in the Table 1: female sex, older age at diagnosis and at HU start, lower WBC count, no phlebotomies need and no palpable spleen were all associated in univariate analysis with CPR achievement. During HU treatment, a thrombotic episode occurred in 36 patients achieving CPR (8.4%) compared to 16 patients without CPR (5.8%) (p=0.162). Among 426 patients achieving CPR, 20 (4.6%) evolved in MF and 10 (2.3%) evolved in BP: among 273 patients without CPR, 20 (7.3%) evolved in MF and 9 (3.3%) evolved in BF (p=0.134 and 0.451, respectively). Ten-year EFS was 79.2% [95%Confidence Interval (CI) 72.1 - 84.8] in patients achieving CPR compared to 67.3% (95%CI 56.9 - 75.7) in patients without CPR (p=0.001) (Fig. 1). Ten-year OS was 80.5% (95%CI 73.9 - 87.1) in patients achieving CPR compared to 74.4% (95%CI 65.6 - 83.2) in patients without CPR (p=0.116). Conclusions In the current clinical practice, HU is effective in inducing CPR in about two thirds of patients with PV treated front-line. CPR is more frequently achieved by patients with lower disease burden, including lower WBC count, and less frequent PHL need and palpable spleen. Notably, >25% of responding patients achieved CPR after >12 months from HU start, suggesting the need for a long period of HU therapy before efficacy evaluation. The clinical importance of CPR is highlighted by a significantly longer EFS in patients achieving this type of response. Disclosures Breccia: Abbvie: Consultancy; Bristol-Myers Squibb/Celgene: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Benevolo:Amgen: Honoraria; Celgene: Honoraria; Novartis: Honoraria. Cavazzini:Pfize: Honoraria; Incyte: Honoraria; Novartis: Honoraria. Heidel:Novartis: Consultancy, Honoraria, Research Funding. Crugnola:Novartis: Honoraria; Celgene: Honoraria; Janssen: Honoraria; BMS: Honoraria. Pane:AbbVie: Consultancy, Other: Travel Expenses, Speakers Bureau; Amgen: Consultancy, Other: Travel Expenses, Speakers Bureau; Daiichi Sankyo: Consultancy, Other: Travel Expenses; Jazz Pharmaceuticals: Consultancy, Other: travel expenses, Speakers Bureau; Novartis pharma SAS: Consultancy, Other: Travel Expenses, Research Funding, Speakers Bureau; 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. Cuneo:Roche: 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; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astra Zeneca: Honoraria; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Krampera:Janssen: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Semenzato:Abbvie: Honoraria; Roche: Honoraria; Takeda: Honoraria. Cavo:Jannsen, BMS, Celgene, Sanofi, GlaxoSmithKline, Takeda, Amgen, Oncopeptides, AbbVie, Karyopharm, Adaptive: Consultancy, Honoraria. Palumbo:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Palandri:Novartis: Consultancy, Honoraria.

Introduction : therapy of chronic phase (CP) chronic myeloid leukemia (CML) is based on tyrosine kinase inhibitors (TKIs) in virtually all patients. Three TKIs are approved for first-line therapy in Italy: imatinib and two second-generation (2G) TKIs, dasatinib and nilotinib. Choice of the front-line TKI is based on a combined evaluation of patient's and disease characteristics, age, risk, comorbidities and concomitant medications. Treating physician's preference and, in some cases, economic considerations, particularly after the advent of generic imatinib, may play a role in TKI selection. However, to date, few data are available on TKI use in a whole nation and on the possible drivers of treatment choice. Aim of the present work was to analyse the use of front-line TKI therapy in a large, unselected cohort of Italian CP-CML patients, correlating patient's features to drug choice. Methods: in the framework of the national Campus CML program, we retrospectively evaluated 1422 patients with CP-CML diagnosed from 2012 and 2019 in 21 haematologic Centres, mostly in academic and/or tertiary hospitals, widespread through the entire Italian territory and treated frontline with imatinib, dasatinib or nilotinib. Results: median age at diagnosis was 59.9 years [interquartile range (IQR) 47.1 - 71.7], with 317 (22.3%) patients under 45 years, 552 (38.8%) between 45 and 65 years and 553 (38.9%) older than 65 years; 821 (57.7%) patients were males. Among 1364 evaluable patients, CML risk according to Sokal score was low in 540 (39.6%), intermediate in 610 (44.7%) and high in 214 (15.7%) patients respectively; the number at low, intermediate or high risk according to the novel ELTS score among 1325 evaluable patients was 759 (57.3%), 402 (30.3%) and 164 (12.4%) respectively. Considering comorbidities, 1003 (70.6%) patients had at least one active disease at the time of CML diagnosis, the most common being hypertension (n=547, 38.5%), previous neoplasms (n=185, 13.0%), diabetes (n=150, 10.6%), chronic bronchopulmonary diseases (n=114, 8.0%), acute myocardial infarction (n=95, 6.7%), previous stroke (n=36, 2.5%) and other vascular diseases (n=98, 6.9%). Among 1335 evaluable patients, 813 (60.9%) were taking at least one concomitant medication, with 280 (21.0%) taking 3-5 drugs and 140 (10.5%) taking 6+ drugs at time of TKI start. As to the frontline therapy, 794 (55.8%) received imatinib and 628 (44.2%) were treated with 2G-TKIs, (226 dasatinib and 402 nilotinib) respectively. According to age, 2G-TKIs were chosen for majority of patients aged 100,000/mm3 vs 38.2% if WBC 10 g/dl; p=0.001) and bigger spleen (65.1% if spleen >5 cm vs 44.8% if spleen 1-5 cm vs 37.3% if spleen not palpable; p5 drugs, respectively (p 45 years, intermediate or high Sokal risk, presence of some comorbidities (2nd neoplasia and stroke) and number of concomitant medications. Conclusions: preliminary results of this observational study on almost 1500 patients show that around 55% of newly diagnosed Italian CP-CML patients receive imatinib as front-line therapy, and that the use of 2G-TKI is prevalent in the younger patients and in those with no concomitant clinical conditions. The counterintuitive finding of imatinib prevalence as frontline treatment in high risk patients might be explained by the older age of these patients. Introduction of the generic formulation in 2018 seems to have fostered the use of imatinib. Figure Disclosures Breccia: Novartis: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Abbvie: Consultancy; Bristol-Myers Squibb/Celgene: Consultancy, Honoraria. Cavazzini:Pfize: Honoraria; Incyte: Honoraria; Novartis: Honoraria. Saglio:Bristol-Myers Squibb: Research Funding; Pfizer: Research Funding; Incyte: Research Funding; Novartis: Research Funding; Ariad: Research Funding; Roche: Research Funding.

Ruxolitinib is a JAK1/2 inhibitor that may control myelofibrosis (MF)-related splenomegaly and symptoms and can be prescribed regardless of age. While aging is known to correlate with worse prognosis, no specific analysis is available to confirm that ruxolitinib is suitable for use in older populations. A clinical database was created in 23 European Haematology Centres and retrospective data on 291 MF patients treated with ruxolitinib when aged ≥65 years were analysed in order to assess the impact of age and molecular genotype on responses, toxicities and survival. Additional mutations were evaluated by a next generation sequencing (NGS) approach in 69 patients with available peripheral blood samples at the start of ruxolitinib treatment. Compared to older (age 65-74 years) patients, elderly (≥75 years) showed comparable responses to ruxolitinib, but higher rates of drug-induced anaemia and thrombocytopenia and worse survival. Nonetheless, the ruxolitinib discontinuation rate was comparable in the two age groups. Number and types of molecular abnormalities were comparable across age groups. However, the presence of high molecular risk (HMR) mutations significantly affected survival, counterbalancing the effect of aging. Indeed, elderly patients with

We investigated whether karyotype analysis and mutational screening by next generation sequencing could predict outcome in 101 newly diagnosed chronic lymphocytic leukemia patients with high-risk features, as defined by the presence of unmutated IGHV gene and/or 11q22/17p13 deletion by FISH and/or TP53 mutations. Cytogenetic analysis showed favorable findings (normal karyotype and isolated 13q14 deletion) in 30 patients, unfavorable (complex karyotype and/or 17p13/11q22 deletion) in 34 cases and intermediate (all other abnormalities) in 36 cases. A complex karyotype was present in 21 patients. Mutations were detected in 56 cases and were associated with unmutated IGHV status (p = 0.040) and complex karyotype (p = 0.047). TP53 disruption (i.e. TP53 mutations and/or 17p13 deletion by FISH) correlated with the presence of ≥ 2 mutations (p = 0.001) and a complex karyotype (p = 0.012). By multivariate analysis, an advanced Binet stage (p < 0.001) and an unfavorable karyotype (p = 0.001) predicted a shorter time to first treatment. TP53 disruption (p = 0.019) and the unfavorable karyotype (p = 0.028) predicted a worse overall survival. A shorter time to chemorefractoriness was associated with TP53 disruption (p = 0.001) and unfavorable karyotype (p = 0.025). Patients with both unfavorable karyotype and TP53 disruption presented a dismal outcome (median overall survival and time to chemorefractoriness of 28.7 and 15.0 months, respectively). In conclusion, karyotype analysis refines risk stratification in high-risk CLL patients and could identify a subset of patients with highly unfavorable outcome requiring alternative treatments.