ALBERT

Description: Deletions and/or mutations of p53 are relatively rare and late events in the natural history of B-cell chronic lymphocytic leukemia (B-CLL). However, it is unknown whether p53 signaling is functional in B-CLL and if targeted nongenotoxic activation of the p53 pathway by using nutlin-3, a small molecule inhibitor of the p53/MDM2 interaction, is sufficient to kill B-CLL cells. In vitro treatment with nutlin-3 induced a significant cytotoxicity on primary CD19+ B-CLL cells, but not on normal CD19+ B lymphocytes, peripheral-blood mononuclear cells, or bone marrow hematopoietic progenitors. Among 29 B-CLL samples examined, only one was resistant to nutlin-3–mediated cytotoxicity. The induction of p53 by nutlin-3 in B-CLL samples was accompanied by alterations of the mitochondrial potential and activation of the caspase-dependent apoptotic pathway. Among several genes related to the p53 pathway, nutlin-3 up-regulated the steady-state mRNA levels of PCNA, CDKN1A/p21, GDF15, TNFRSF10B/TRAIL-R2, TP53I3/PIG3, and GADD45. This profile of gene activation showed a partial overlapping with that induced by the genotoxic drug fludarabine. Moreover, nutlin-3 synergized with both fludarabine and chlorambucil in inducing B-CLL apoptosis. Our data strongly suggest that nutlin-3 should be further investigated for clinical applications in the treatment of B-CLL.

Description: Abstract 2293 Background. Dasatinib is a tyrosine kinase inhibitor that has 325-fold greater in vitro activity against native BCR-ABL (breakpoint cluster region-Abelson leukemia virus) compared with imatinib and can overcome primary (intrinsic) and secondary (acquired) imatinib resistance. A phase III dose optimization study showed that in patients with chronic phase (CP) chronic myeloid leukaemia (CML), dasatinib at 100 mg once daily improved the safety profile while maintaining efficacy compared with the previously recommended dose of 70 mg twice-daily. Few data exist on the efficacy and safety of dasatinib in elderly CML patients. Aims. The aim of the study was to evaluate the impact of dose reduction on dasatinib efficacy. Methods. We revised 129 unselected pts with CP CML aged 〉60 yrs treated in 21 Italian haematological Institution, who received dasatinib after being resistant/intolerant to imatinib. Among this group 70 pts were given dasatinib at adjusted-dosage below the standard recommended dose of 100 mg daily for 〉 6 months. In relation to the dose modulation, patients were divide in 2 groups: group-a (21/70, 30%) received a starting dose of 20 mg daily dose excalated to the maximum tolerated dose of 70 mg daily; group-b (49/70=70%) received a starting dose of 100 mg daily, successively adhusted according to tolerance. Sokal score was evaluable for 59/70 patients (low for 16, intermediate for 28, high for 15). All patients were analyzed for haematological, cytogenetic and molecular response. Results. All patients were fully evaluable for response at a median FU time of 25 mos (range 0,7- 56,3 mos). Eight pts (11.4%) discontinued treatment due to intolerance. Response rates were 25,7% (18pts), 24.3% (17 pts), 15.7% (11 pts), 10% (7 pts), 12.8% (9 pts) for complete haematologic response (RHC), complete cytogenetic response (RCyC), major molecular response (RMolM), complete molecular response (RMolC), partial cytogenetic response (RCyP), respectively. Median Cumulative event free survival (EFS) and overall survival (OS) were 21.3 and 27.3 mos respectively. We did not observe any significative difference in term of response between group A and B receiving different doses. Interestingly, 3/9 patients in group A who had a transient loss of molecular response achieved major molecular response after dose escalation to 50 mg. Conclusions: Dasatinib given at a lower dose than currently recommended is still effective in elderly CML patients. However, more close molecular monitoring is advised when lower doses are prescribed. Studies in larger series are warranted to better define optimal dose and schedule of dasatinib in this frail patient population. Disclosures: Rosti: Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bristol Myers Squibb: Honoraria, Speakers Bureau; Roche: Speakers Bureau.

Description: It is unclear whether karyotype aberrations that occur in regions uncovered by the standard fluorescence in situ hybridization (FISH) panel have prognostic relevance in chronic lymphocytic leukemia (CLL). We evaluated the significance of karyotypic aberrations in a learning cohort (LC; n = 64) and a validation cohort (VC; n = 84) of patients with chronic lymphocytic leukemia with “normal” FISH. An abnormal karyotype was found in 21.5% and 35.7% of cases in the LC and VC, respectively, and was associated with a lower immunophenotypic score (P = .030 in the LC, P = .035 in the VC), advanced stage (P = .040 in the VC), and need for treatment (P = .002 in the LC, P = 〈 .0001 in the VC). The abnormal karyotype correlated with shorter time to first treatment and shorter survival in both the LC and the VC, representing the strongest prognostic parameter. In patients with chronic lymphocytic leukemia with normal FISH, karyotypic aberrations by conventional cytogenetics with novel mitogens identify a subset of cases with adverse prognostic features.

Description: Background: The European LeukemiaNet (ELN) response criteria are widely used to decide, at given time points, when the treatment with tyrosine-kinase inhibitors (TKIs) of CML patients should be continued (optimal response, OR), when a careful monitoring is required (warning, W) or when the therapy should be changed (failure, F). The 2013 ELN response criteria are the same for all chronic phase CML patients, irrespective of the prescribed TKI, but the time to response is influenced by the first-line TKI. Despite faster responses, a clear survival advantage of 2nd generation TKIs over imatinib (IM) has not been demonstrated yet. A validation of the 2013 ELN response definitions and an analysis of their prognostic impact in IM-treated patients may provide important information. Aims: The aim of our study was to assess the significance of 2013 ELN response criteria in CML patients treated frontline with IM, investigating whether or not optimal responders, warnings or failures at 3, at 6 and at 12 months have a different long-term outcome. Methods: 559 patients enrolled within 3 prospective clinical trials (NCT00514488, NCT00510926, observational trial CML/023) were analyzed (ITT population of each study). The 3-month response according to 2013 ELN criteria was not fully evaluable due to missing cytogenetic analysis in 452/559 patients, so we focused on the early molecular response (EMR, BCR-ABL 〈 10% at 3 months), corresponding to OR. The responses at 6 and 12 months were retrospectively defined according to 2013 ELN criteria: F, BCR-ABL 〉 10% and/or Ph+ 〉 35% at 6 months, BCR-ABL 〉 1% and/or Ph+ 〉 0 at 12 months; OR, BCR-ABL 〈 1% and/or Ph+ 0 at 6 months, BCR-ABL 〈 0.1% at 12 months; W: intermediate conditions. As the ELN criteria changed over time, not all the failures switched to alternative treatment. Progression: transformation to advanced phases (2013 ELN definitions) at any time, including after treatment discontinuation. Overall survival (OS): all the deaths at any time (in-study or off-study) were included. Leukemia-unrelated death: known cause of death, no progression, CCyR and/or MMR 〈 6 months prior to death; all other deaths were classified as leukemia-related (LRD). The cumulative incidence of LRD was estimated considering the competing risk of leukemia-unrelated death. Results: The median follow-up was 76 months (66-99 months). The patients with OR at 3 months were 82%; the patients with OR-W-F at 6 months were 76%, 14% and 10%, respectively; the patients with OR-W-F at 12 months were 65%, 20% and 14%, respectively. The OS, the progression-free survival (PFS) and the cumulative incidence of LRD according to the presence-absence of EMR were 87-81% (p=0.015), 85-81% (p=0.035) and 11-5% (p=0.019), respectively. Combining the Sokal score and the EMR, the patients were divided into 4 groups, low and intermediate risk/responders, low and intermediate risk/not responders, high risk/responders, high risk/not responders: the OS and the cumulative incidence of LRD across the 4 groups were 88%, 84%, 86% and 70% (p=0.005, Figure 1) and 3%, 9%, 10% and 20% (p

Description: Abstract 2281 Introduction. Imatinib is the standard of care for CML in early chronic phase. Until now, even in stable complete molecular response, discontinuation of imatinib is not recommended, and imatinib remains a life-saving drug to be taken chronically. Long term side effects, including the incidence of second malignancies, represent a potential relevant issue. Roy et al (Leukemia 2005) reported an unexpected incidence of second neoplasms in patients treated with imatinib after interferon (6/189 patients, 3.2%; urinary tract cancer: 4/6). In contrast, an analysis performed by Novartis Pharma (Pilot et al, Leukemia 2006) on 9518 patients treated with imatinib (including pre-treated patients) did not provided evidence for an increased overall incidence of second malignancies. According to epidemiologic data (Registro Tumori) in Italy, the annual incidence of neoplasms varies from 1%, in the range of age between 50 and 69 years, to 3% for patients over 70 years. AIM. To evaluate the incidence of second malignancies in CML patients treated with imatinib frontline. METHODS. Overall, 559 patients have been enrolled in 3 concurrent clinical studies of the GIMEMA CML Working Party: CML/021, Imatinib 800 mg in intermediate Sokal risk patients (Clin Trials Gov. NCT00514488); CML/022, Imatinib 400 mg vs 800 mg in high Sokal risk patients (Clin Trials Gov. NCT00510926); CML/023, observational, Imatinib 400 mg. We evaluated the incidence of II malignancy notified as severe adverse events reported by the GIMEMA clinical Centers. RESULTS. The median age at the diagnosis of CML was 52 (extr.18 – 84) years; 308 patients (55%) were ≥ 50 years. The median follow-up is currently 60 months. Eighteen patients (3.2%) developed a second malignancy at a median time of 20 months (extremes 2 – 52) from the start of imatinib therapy (Table 1); 4 of these malignancies (2 colon cancer and 2 NHL) were diagnosed within 6 months. All patients were older than 50 years (median 64, extremes 50 – 79) at the diagnosis of the second malignancy. Fifteen out of the 559 (2.7%) patients died due to second neoplasm progression. CONCLUSION. In this multicentre nation-wide experience of CML patients treated with imatinib frontline, the incidence of life-threatening or requiring hospitalization secondary neoplasms (severe adverse events), seems not to be superior to the observed incidence of neoplasm in the Italian national population. In particular, in contrast to what previously reported, no increased incidence of urinary tract cancer was observed. Disclosures: Gugliotta: Novartis: Honoraria. Castagnetti: Novartis: Honoraria; Bristol Myers Squibb: Honoraria. Martinelli: Novartis: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Pfizer: Consultancy. Pane: Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees. Saglio: Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Baccarani: Novartis: Consultancy, Research Funding, Speakers Bureau; Bristol Myers Squibb: Consultancy, Research Funding; Wyeth: Consultancy, Research Funding. Rosti: Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bristol Myers Squibb: Honoraria, Speakers Bureau; Roche: Speakers Bureau.

Description: Tyrosine-kinase inhibitors (TKIs)have completely changed the expected survival of chronic myeloid leukemia (CML) patients which is now approaching that of the general population: a relevant proportion of CML patients are currently elderly or very elderly. Very elderly patients represent generally a small proportion in published experiences. Older CML patients imatinib treated, as it happens in the general population, receive other drug treatments for associated chronic illnesses. Our aim is to assess if and which classes of concomitant drugs have an impact on cytogenetic response in chronic phase (CP)-CML very elderly (age 〉75 years) patients. Two hundred and twelve very elderly CP-CML patients, imatinib treated at 33 italian hematological institutions have been retrospectively evaluated. Median age at diagnosis was 78.5 years (range 75.0-93.0); 111 (52.4%) were male. Sixty-two (29.2%) were Sokal high risk. Sixty-seven (31.8%) were treated with reduced dose imatinib (400 mg/day. Concomitant drugs were 1-2 in 73 (34.4%) patients, 3-4 in 59 (27.8%), and 〉5 in 64 (30.2%); 16 (7.6%) did not assume any concomitant drug. Drugs more frequently used were antiplatelets, assumed by 104 (49.1%) patients, followed by diuretics in 91 (42.9%) patients, proton pump inhibitors (PPIs) in 86 (40.6%), ACE inhibitors in 55 (25.9%), beta blockers in 44 (20.7%), angiotensin II receptors blockers (ARB) in 41 (19.3%), calcium channel blockers in 34 (16%), statins in 25 (11.8%), and alpha blockers in 11 (5.2%). Univariate logistic regression models were computed to assess the association between cytogenetic response after 6 or 12 months of imatinib treatment and number of concomitant drugs or selected drug classes. Statistical analyses were done using JMP 11.1 (SAS Institute Inc., Cary, NC, USA). Complete cytogenetic response (CCyR) was obtained in 124 (58.8%) patients, of whom 70 (33%) within 6 months. Consequently, we focused our study on the impact of number and types of drugs on CCyR rate, which represents the primary therapeutic endpoint in the elderly. Cytogenetic response distribution according to concomitant drugs is reported in table 1. We did not find any significant correlation between number of concomitant drugs, single classes of antihypertensive drugs, antiplatelets, PPIs or statins and CCyR rate at 6 or 12 months. Even though few pharmacokinetic interactions are reported between imatinib and some of medications we considered, this does not seem to have an impact on cytogenetic response rate in our cohort. Indeed, our results confirm the well-known safety and efficacy of imatinib also in very elderly CML patients. Table 1. Cytogenetic response according to concomitant drugs Drug classes Cytogenetic response CCyR 12 months No CCyR Antiplatelets (n=104) 38 (36.5%) 31 (29.8%) 11 (10.6%) 24 (23.1%) Diuretics (n=91) 32 (35.2%) 21 (23.1%) 13 (14.3%) 25 (27.4%) Proton pump inhibitors (n=86) 30 (34.9%) 22 (25.6%) 13 (15.1%) 21 (24.4%) ACE inhibitors (n=55) 19 (34.6%) 11 (20%) 12 (21.8%) 13 (23.6%) Beta blockers (n=44) 18 (40.9%) 11 (25%) 3 (6.8%) 12 (27.3%) Angiotensin II receptor blockers (n=41) 19 (46.3%) 11 (26.8%) 5 (12.3%) 6 (14.6%) Calcium channel blockers (n=34) 10 (29.4%) 7 (20.6%) 6 (17.7%) 11 (32.3%) Statins (n=25) 9 (36%) 7 (28%) 2 (8%) 7 (28%) Alpha blockers (n=11) 4 (36.4%) / 1 (9.1%) 6 (54.5%) Disclosures Castagnetti: Novartis: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; ARIAD: Consultancy, Honoraria. Abruzzese:BMS, Novartis, Pfizer, Ariad: Consultancy. Tiribelli:Bristol Myers Squibb: Consultancy, Speakers Bureau; Ariad Pharmaceuticals: Consultancy, Speakers Bureau; Novartis Farma: Consultancy, Speakers Bureau. Rosti:Novartis: Honoraria, Research Funding, Speakers Bureau; Bristol Myers Squibb: Honoraria, Research Funding, Speakers Bureau.

Description: Abstract 453 Background: Imatinib (IM) 400 mg daily is the standard treatment for Ph+ Chronic Myeloid Leukemia (CML) in early Chronic Phase (ECP). Nilotinib (NIL) is a 2nd generation tyrosine kinase inhibitor (TKI) with superior efficacy to IM (phase 3 ENESTnd trial). NIL has been approved for the frontline treatment of CML in many countries. The treatment with more than one TKI, according to the principles of cancer polychemotherapy, may improve the response rates and may decrease the frequency of drug-resistance. The combination of different TKIs is potentially toxic, difficult to be explored in the ECP setting. The sequential administration of IM and NIL is worth to be investigated because a significant proportion of CML patients treated with a single TKI as monotherapy develops primary or secondary resistance. Aims: To evaluate the response (either cytogenetic and molecular) and the outcome of ECP Ph+ CML patients treated with the sequential administration of NIL and IM. Methods: A phase 2 study was conducted by the GIMEMA CML WP (ClinicalTrials.gov. NCT00769327). NIL was administered first because it has a more rapid therapeutic effect. Schedule: NIL 400 mg twice daily for 3 months; IM 400 mg daily for the next 3 months; then, NIL and IM turning every 3 months, for a total duration of 24 months (study core). The 3-month rotation schedule was respected, irrespectively of temporary discontinuations. The primary end-point was the Complete Cytogenetic Response (CCgR) rate at 12 months. If the conventional cytogenetic analysis resulted not evaluable, a FISH analysis was performed. If one of the 2 drugs was permanently discontinued for adverse event (AE), the patient remained in study, continuing the treatment with the other drug (except for cardiac AEs). Definitions: Major Molecular Response (MMR): BCR-ABL/ABL ratio 〈 0,1%IS; failure: according to 2009 ELN recommendations; event: failure, permanent discontinuation of both drug for any reason, patient refusal. All the analysis were performed according to the ITT principle. Results: 123 patients have been enrolled in 38 italian hematologic Centers; median age 56 years (range 18–84); 33% low, 45% intermediate and 22% high Sokal score; median follow-up 21 months (at least 12 months observation, 24 months by November 2011). The cumulative CCgR rate by 12 months was 87%; CCgR at each milestone: 68% at 3 months, 73% at 6 months, 67% at 12 months (primary efficacy variable). The cumulative MMR rate by 12 months was 82%, while the rates of MMR at 3, 6 and 12 months were 59%, 62% and 60%, respectively. The discrepancies between cumulative response rates and response at each timepoint were mainly due to the number of patients not evaluable at each timepoint (10% of cytogenetic analysis not evaluable at 12 months) and to protocol discontinuation in stable CCgR and/or MMR. The incidence of hematologic AEs was low. Non-hematologic AEs or lab abnormalities grade 〉 2 observed in 〉5 % of patients were as follows: NIL - skin rash, pruritus, bilirubin increase, transaminase increase, lipase increase; IM - fluid retention, periorbital edema. AEs were manageable with appropriate dose adaptations. Four patients (3%) showed a prolongation of the QTcF above 450 msec (none above 500 msec). At the end of the first 12 months, 95 patients (77%) remained on study: 6 and 3 on NIL and IM monotherapy, respectively, 86 on sequential treatment with both drugs; 15% of patients permanently reduced the NIL dose to 400 mg daily and 9% of patients permanently reduced the IM dose to 300 mg daily. During the first year, 28 patients (23%) experienced an event: 10 treatment failure (8%); 2 death in CP (2%); 16 refusal, protocol violation or AE (13%). Six out of the 10 patients who failed the treatment progressed to advanced phase (3 patients: detection of a T315I mutation). Conclusions: The cumulative response rates achieved with a sequential administration of NIL and IM seem to be superior to the historical data of IM alone. The response rates at each timepoint, lower than expected, were probably due to the high number of not evaluable patients and to the number of patients not continuing the study despite a stable CCgR/MMR. However, if compared to the excellent results of 2nd generation TKI as monotherapy in ECP CML (single and randomized trials), the present analysis do not support an alternating schedule of NIL and IM as frontline treatment of ECP CML. Acknowledgments: European LeukemiaNet, COFIN, Bologna University, BolognAIL Disclosures: Castagnetti: Novartis Pharma: Honoraria; Bristol-Myers Squibb: Honoraria. Rosti:Novartis: Consultancy; Bristol Myers Squibb: Consultancy; Novartis: Research Funding; Novartis: Honoraria; Bristol Myers Squibb: Honoraria. Soverini:Novartis: Consultancy; ARIAD: Consultancy; Bristol-Myers Squibb: Consultancy. Martinelli:Bristol-Myers Squibb: Consultancy; Novartis: Consultancy, Research Funding.

Description: Abstract 1678 Background. Imatinib mesylate (IM) is the therapeutic standard for chronic myeloid leukemia (CML), but nilotinib and dasatinib, at least in selected patients, have the potential to replace it. The early prediction of poor outcome is important to optimize the treatment strategy. In IM-treated patients, BCR-ABL transcript levels according to the International Scale (IS) 〉 10% at 3 and 〉 1% at 6 months were able to identify high-risk groups (Marin et al, JClinOncol 2011; Hanfstein et al, Leukemia 2012). Similar analysis were performed within the IM arms of the ENESTnd trial (Hochhaus et al, EHA 2012) and the DASISION trial (Jabbour et al, EHA 2012). Methods. To investigate the prognostic impact of BCR-ABLIS levels at 3 and 6 months on the future response status and the long-term outcome of CML patients treated frontline with IM, we analyzed 559 patients enrolled within 3 trials of the GIMEMA CML WP (ClinTrialsGov NCT00514488/NCT00510926, observational trial CML023). Patients with evaluable QPCR sample at 3 and 6 months: 487/559 (87%) and 492/559 (88%), respectively. Definitions: major molecular response (MMR): BCR-ABLIS ratio 1%) at 3 and 6 months were analyzed. Patients with events or censored within 3 or 6 months were excluded from the respective analysis. Receiver operating characteristic (ROC) curves were used for descriptive purposes. Results. Median age: 52 years (range 18–84). IM dose: 76% 400mg, 24% 800mg. Sokal score: 39% low, 39% intermediate, 22% high; EUTOS score: 93% low, 7% high. Median follow-up: 76 months (range: 7–99); 95% of patients had at least 5-year observation. BCR-ABLIS at 3 months: ≤1% in 336/487 (69%), 〉1% to ≤10% in 120/487 (25%) and 〉10% in 31/487 (6%). BCR-ABLIS at 6 months: ≤1% in 425/492 (86%), 〉1% to ≤10% in 54/492 (11%) and 〉10% in 13/492 (3%). Responses and outcomes according to transcript levels are presented in table 1. Patients with BCR-ABLIS 〉10% at 3 months achieved inferior CCgR and MMR rates at 1 year and inferior MR4.0 rate at 2 years, but the long-term outcome was comparable to patients with transcript levels 〈 10%. On the contrary, a BCR-ABLIS 〉1% at 3 months was associated, not only to lower subsequent response rates, but also to significantly inferior FFS, PFS and OS. The BCR-ABLIS levels able to predict for FFS, PFS and OS with maximal sensitivity and specificity (ROC curves) were 1.9%, 0.8% and 0.8%, respectively. Results were similar, with small differences, in the 6-month analysis. Conclusions. In a multicentric nationwide experience, the proportion of patients with BCR-ABLIS transcript levels 〉10% at 3 and 6 months was low. The risk distribution and the proportion of patients treated with high-dose IM may explain, at least in part, the differences with other published reports. At 3 and 6 months, a BCR-ABLIS cutoff of 1% was a reliable surrogate marker of response and outcome. A transcript level 〉10% identified a smaller cohort with inferior responses, but failed to predict the long-term outcome. A BCR-ABLIS level 〉1% at 3 and 6 months represents a warning, requiring a close monitoring. A switch to 2nd generation tyrosine kinase inhibitors should be considered. Acknowledgments. University of Bologna, BolognaAIL, COFIN, Fondazione Carisbo. Disclosures: Castagnetti: Bristol Myers Squibb: Consultancy, Honoraria, Speakers Bureau; Novartis Pharma: Consultancy, Honoraria, Speakers Bureau. Gugliotta:Novartis: Consultancy, Honoraria; Bristol-Myers-Squibb: Consultancy, Honoraria. Breccia:Bristol Myers Squibb: Consultancy; Novartis: Consultancy. Abruzzese:Bristol Myers-Squibb and Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees. Cavazzini:Novartis Pharma: Honoraria; Bristol Myers Squibb: Honoraria. Soverini:Novartis: Consultancy; Bristol-Myers Squibb: Consultancy; ARIAD: Consultancy. Saglio:Novartis: Consultancy, Speakers Bureau; BMS: Consultancy, Speakers Bureau; Pfizer: Consultancy. Martinelli:Bristol-Myers-Squibb: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau. Baccarani:ARIAD, Novartis, Bristol Myers-Squibb, and Pfizer: Consultancy, Honoraria, Speakers Bureau. Rosti:Novartis Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Speakers Bureau; Pfizer: Speakers Bureau.

Description: Abstract 1680 Background. Chronic myeloid leukemia (CML) is characterized by the presence of the BCR-ABL1 hybrid gene. Different types of BCR-ABL1 fusion transcripts can be found, but the most frequent are the e13a2 (b2a2) and the e14a2 (b3a2). In the tyrosine kinase inhibitors (TKIs) era, few data about the prognostic significance of the transcript type in early chronic phase (ECP) CML are available. Three larger studies suggested that the e13a2 transcript may have an adverse prognostic impact in ECP CML patients treated with imatinib (IM): Vega-Ruiz et al. (251 patients, ASH 2007) reported inferior molecular responses; Lucas et al. (71 patients, Haematologica 2009) reported lower cytogenetic response rates and lower event-free survival (EFS); the GIMEMA CML WP (493 patients, EHA 2011) reported a slower time to major molecular response (MMR) with inferior EFS and progression-free survival (PFS). To our knowledge this is the first evaluation of the prognostic influence of the BCR-ABL1 transcript type on the responses and the outcome of ECP CML treated frontline with nilotinib (NIL). Methods. The CML Italian Registry of Nilotinib includes 215 patients treated with NIL-based regimens. The patients were enrolled within 2 multicenter phase II studies conducted by the GIMEMA CML WP (ClinicalTrials.gov. NCT00481052 and NCT00769327) or treated at the “S. Orsola-Malpighi” University Hospital (Bologna, Italy), with NIL 300 mg BID or 400 mg BID as initial treatment. All the registered patients were analyzed. Patients expressing rare transcripts and patients with both b2a2 and b3a2 transcripts were excluded: 201 out of 215 patients were evaluable, 81 (40%) with e13a2 transcript and 120 (60%) with e14a2 transcript. Differences between groups were tested using χ2 test, Fisher exact test or t-test, as appropriate. Response monitoring: conventional cytogenetic examination (bone marrow) and QPCR (peripheral blood). Definitions: MMR: BCR-ABLIS ratio

Description: Background and aims The e13a2 and the e14a2 are the most frequent BCR-ABL1 transcripts in chronic myeloid leukemia (CML) patients. The aim of the present study was to assess the prognostic value of the e13a2 (b2a2) or the e14a2 (b3a2) fusion transcripts on the long-term outcome of early chronic phase (ECP) CML patients treated frontline with imatinib mesylate (IM). Few studies, mostly based on a small number of patients or with a relatively short observation, have been published, particularly in ECP setting. Due to partially conflicting data, the transcript type is not actually considered an established baseline prognostic factor. To our knowledge, this is the first long-term analysis conducted in the context of large prospective studies. Methods A retrospective analysis of 3 GIMEMA CML WP prospective clinical studies (NCT00514488, NCT00510926, observational study CML/023) was performed. All the 559 enrolled patients were analyzed. A qualitative RT-PCR for BCR-ABL1 transcript was routinely performed at enrollment. Patients expressing rare transcripts or with both e13a2-e14a2 transcripts were excluded: 493 out of 559 patients were included, 203 (41%) with e13a2 transcript and 290 with e14a2 transcript (59%). Definitions. Major molecular response (MMR): BCR-ABL1IS ratio