ALBERT

Description: Background: MPNs including Polycythemia Vera (PV), Essential Thrombocythemia (ET) and Primary Myelofibrosis (PMF), are clonal hematopoietic diseases in which the discovery of molecular driver mutations (JAK2, CALR, MPL) has deeply modified diagnostic approach in recent years. To date available data on epidemiology of MPNs and perspective analysis are rare. Our aim is to study the incidence of MPN Ph negative in a specific region of Italy named Latium and its variability across five years. Moreover we prospectively report the general features of our population. Method: We present here the prospective epidemiologic analysis of 1116 adult patients affected by MPNs (PV=289, ET=550, PMF=209) diagnosed according to 2008 WHO criteria, from January 2011 to December 2015 in 15 hematological Centers (5 academic and 10 community-based Hospitals) in Latium. A total of 289 PV, 550 ET and 209PMF were identified. The overall incidence rate of 289PV was 1.0/105 in 2011 and 2012, 1.1/105 in 2013, 0.9/105 in 2014 and 2015. The overall incidence rate of 550ET was 2.0/105 in 2011, 2.4/105 in 2012, 2.2/105 in 2013, 1.8/105 in 2014 and 1,2/105 in 2015 and the overall incidence rate of 209PMF was 0.7/105 in 2011 and 2012, 1.0/105 in 2013, 0.7/105 in 2014 and 0.5/105 in 2015. We have observed also 63 cases of MPNu (36M/32F) and the incidence rate was 0.3/105 in 2011 and 2012, 0.14/105 in 2013, 0.24/105 in 2014 and 0.22/105 in 2015. Baseline features of PV, ET and PMF patients are summarized in table 1. We have also analyzed the presence of comorbidities including obesity, arhythmia and neoplasia observed at the diagnosis in 1.6, 6.2 and 4% of all population, respectively; thirty-five percent of 1116 pts presented other comorbidities such as diabetes, inflammatory bowel disease, renal and liver failure. As thrombotic risk factors we considered diabetes, dislipidemia, smoke, essential hypertension and thrombophilia observed in 11,8, 16,2, 13,2, 51,7 and 3% of total pts, respectively. Conclusions: We confirm in our prospective observational protocol the overall incidence of MPN Ph negative, previously reported in the literature and the major incidence of male gender in PV and PMF, female in of ET. The annual incidence from 2011-2015 in Latium is remained substantially the same during the observation period. The decreasing trend observed in 2015 is probably due to the different update of some Centers that was done in October 2015 not including patients diagnosed in the last two months. Disclosures Latagliata: Novartis: Consultancy, Honoraria; Bristol Myers Squibb: Honoraria; Celgene: Honoraria; Janssen: Consultancy, Honoraria; Shire: Honoraria. Breccia:Pfizer: Honoraria; Novartis: Consultancy, Honoraria; Bristol Myers Squibb: Honoraria; Celgene: Honoraria; Ariad: Honoraria. Cimino:Celgene: Honoraria; Bristol-Mayer: Honoraria.

Description: Background Thrombotic episodes are the major complication in the follow-up of Philadelphia negative Myeloproliferative Neoplasms (MPN), with high morbidity and mortality, as reported in several retrospective studies. At present, however, few prospective data are available on the early incidence of these complications. Methods To address this issue, we report on 1087 patients [M/F 508/579, median age 67.6 years, interquartile range (IQR) 55.2 - 75.9] with newly diagnosed MPN enrolled in the prospective database of our regional cooperative group since January 2011. Of them, 571 (52.5%) had Essential Thrombocythemia (ET), 303 (27.9%) Polycythemia Vera (PV) and 213 (19.6%) Primary Myelofibrosis (PMF). The main clinical features at diagnosis of the whole cohort and according to the different MPNs are reported in the Table 1. Results On the whole, 22 episodes of thrombotic complications were reported in 1087 patients (2.0%) at a median interval from diagnosis of 18.2 months (IQR 7.4 - 29.7): in particular, 15 (68.1%) were arterial (8 cerebral, 2 coronaric, 4 in the lower limbs, 1 splancnic) and 7 (31.9%) venous (5 in the lower limbs and 2 in the upper limbs). As to the incidence of early thrombosis in the different MPNs, they were 13/571 (2.2%) in ET patients, 5/303 (1.6%) in PV patients and 4/213 (1.8%) in PMF patients (p=0.810): median time from diagnosis to thrombotic event was also similar in the 3 MPNs (p=0.311). The 4-year cumulative Thrombosis-Free Survival (TFS) of the whole cohort was 97.3% (95%CI 96.0 - 98.6): there was no difference among the 3 MPNs as to 4-year TFS [96.7% (95%CI 94.8 - 98.6) in ET, 97.8% (95%CI 95.9 - 99.7) in PV and 98.7% (95%CI 96.9 - 100) in PMF, respectively, p=0.668). Several clinical features at diagnosis (age, gender, Hb levels, WBC and PLT counts, spleen enlargement, JAK-2 V617F mutation and previous thrombotic events) were evaluated for a role in predicting thrombotic events: only age (p=0.009) and previous thrombotic events (p=0.009) were significant. Conclusions The incidence of early thrombosis seems low in the first 4 years after diagnosis of MPN based on our prospective database, without any difference among ET, PV and PMF: it is worth of note that only age and previous thrombotic events had a predictive role, thus confirming many retrospective reported data and reinforcing the prognostic value of old scoring system for thrombotic risk in MPN. Table 1 Table 1. Disclosures Breccia: Ariad: Honoraria; Pfizer: Honoraria; Novartis: Consultancy, Honoraria; Bristol Myers Squibb: Honoraria; Celgene: Honoraria. Latagliata:Novartis: Consultancy, Honoraria; Bristol Myers Squibb: Honoraria; Celgene: Honoraria; Janssen: Consultancy, Honoraria; Shire: Honoraria.

Description: Background and rationale In chronic myeloid leukemia (CML) about half of patients (pts) achieving a deep and stable molecular response (MR) 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 to possibly identify more and better CML patients suitable for an efficacious discontinuation are today focus of research in CML. Leukemia stem cells (LSCs) are supposed to be the reservoir of disease. We first showed in a cross-sectional study including 112 pts in TFR for a median of 31 months (mos) that residual circulating CD34+/CD38-/CD26+ CML-specific LSCs were still detectable in the majority of CML pts despite stable and deep molecular response. This evidence suggested that the level of BCR-ABL transcript only may not reflect the actual residual CML LSCs burden and that there could be a "threshold" of LSCs predicting a successful TFR. Aims To further study the behavior of residual LSCs during TKI discontinuation we designed a prospective multicentered study (AIRC IG 20133 study) in which we monitored circulating CD26+ LSCs in CML pts from the time of TKI discontinuation until molecular relapse. Methods CML pts meeting the current molecular criteria for TKI withdrawal entered this multicenter study. At TKI stop (baseline) and at +1, +2, +3, +6, + 12 mos after discontinuation and at any time if molecular relapse, CML pts were evaluated for peripheral blood number of CD34+/CD38-/CD26+ LSCs by centralized flow-cytometry analysis and for BCR-ABL transcript level by standard (IS) quantitative RT-PCR assay. Results 49 consecutive CML pts were enrolled in the study so far. Pts characteristics at diagnosis, type of TKI, disease response and treatment duration before discontinuation are shown in Tab. 1. After a median time of 7 mos since TKI stop (range 1-24), 13/49 (26.5%) pts lost their molecular response and restarted TKI treatment. Median time to relapse after discontinuation was 4 mos (range 2-7). 36/49 (73.4%) pts are still in TFR after a median time of 7.5 mos (range 1-24). If considering a cut-off of 6 mos from discontinuation as the period with higher risk of relapse, 14/36 pts actually in TFR have discontinued treatment for ≤ 6 mos (range 1-6) while 22/36 pts are in TFR for a median of 10 mos (range 7-24). Regarding residual CML LSCs evaluation, at baseline 23/49 (46%) pts had still measurable circulating CD26+LSCs with a median number of 0.0204µ/L (range 0.0077-0.1197), while 26/49 (54%) had no detectable CD26+ LCSs. Considering the small number of molecular relapses no statistical difference in number of residual CD26+ LSCs at time of discontinuation was shown between pts losing vs maintaining TFR (13 pts median CD26+ LSC 0.0237/µ/L, range 0-0.1197 and 36 pts median CD26+ LSCs 0.0204/µ/L, range 0-0.1039, respectively). However, the number of pts with undetectable CD26+ LSCs at baseline was 6/13 (45%) and 20/36 (55%) in the two subgroups, respectively. Considering subsequent time points, the 13 relapsed pts showed a small yet progressive increase of residual CD26+ LSCs number until molecular relapse, while the 36 pts in TFR showed a fluctuation of CD26+ cells number. However, Kendall rank correlation coefficient, Mood test and bi-linear relation model of the whole cohort showed no correlation between BCR-ABL/ABLIS ratio and number of residual CD26+ LSCs either at baseline or at each time points after discontinuation, thus confirming our previous observations. Conclusions Yet very preliminary our results showed that CD26+ LSCs are detectable at time of TKI discontinuation and during TFR. Moreover, at least for the observation median time of the study (7.5 mos) the persistence of "fluctuating" values of residual CD26+ LSCs do not hamper the possibility to maintain a stable TFR. Due to the short follow up and the small number of molecular relapsed pts we could not find a threshold of CD26+ LSCs predictive of TFR loss. Our data may suggest other factors then LSCs "burden" to play an active role in controlling disease recurrence. Additional studies evaluating CD26+ LSCs ability to modulate the immune system through a variable expression of immune response inhibitory molecules and through their interactions with effectors cells are ongoing. Table Disclosures Bocchia: Novartis: Honoraria; Incyte: Honoraria; BMS: Honoraria. Pregno:Bristol Myers Squibb: Honoraria; Incyte: Consultancy, Honoraria; Novartis: Honoraria; Pfizer: Honoraria. Abruzzese:Incyte: Consultancy; Novartis: Consultancy; Pfizer: Consultancy; BMS: Consultancy. Crugnola:Novartis: Honoraria; Incyte: Honoraria. Iurlo:Pfizer: Honoraria; BMS: Honoraria; Incyte: Honoraria; Novartis: Honoraria. Galimberti:Roche: Speakers Bureau; Celgene: Speakers Bureau; Novartis: Speakers Bureau. Liberati:Bristol & Mayer: Honoraria; Takeda: Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria; Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy; Amgen: Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria.

Description: Introduction: Pregnancy requires, and is an important motivator of tyrosine kinase inhibitor (TKI) cessation in patients with chronic myeloid leukemia (CML). While conventional treatment free remission (TFR) attempts may allow observation of limited rise in BCR-ABL prior to expected TKI re-exposure, TKI cessation in pregnancy affords longer observation of BCR-ABL kinetics without automatic TKI re-exposure. Mathematical models and clinical observation of BCR-ABL kinetic rise during TKI discontinuation or planned cessation estimate of 'doubling time' (DT) of roughly 9 days (Branford et al., Blood 2012). In order to explore the impact of pregnancy, we studied BCR-ABL kinetics and response stability during and after pregnancy. Methods: We collected cases of successful pregnancies (conception-〉childbirth) at 4 CML referral centers including the following conditions: 1/conception occurring while on TKI therapy; 2/TKI therapy stopped for the purpose of conception; and 3/ pregnancy during TKI cessation within a TFR clinical trial. Cases with early spontaneous/elective abortion, treated with interferon during pregnancy or with less than 2 BCR-ABL transcripts recorded during pregnancy were excluded. Doubling time (DT) was calculated using the following formula: DT = ln2/k, where k = (ln(b)-ln(a))/d, where (a) and (b) is the value before the rise and at the rise, and (d) is days. Results: In total 50 pregnancies in 39 patients were analyzed; 10 patients had 〉1 pregnancy. Four pregnancies were in the context of TFR study (2 enrolled at conception, 1 patient 28mo in TFR, 1 patient 5mo in TFR). The majority of cases were on first-line treatment at TKI cessation and median duration of TKI therapy was 6.4 years (range 0.5-16.2); 58% were in deeper molecular response (MR4 or deeper) and 34% in major molecular response (MMR) at TKI cessation. Patient characteristics are summarized in Table 1. Median time off TKI was 10.1 months (range 5.4-71.5). Of 44 pregnancy cases within MMR or deeper at TKI cessation, 54.5% maintained MMR or greater; 60.7% of those in MR4 or deeper and 43.7% for those in MMR, respectively. Several cases were associated with decline in BCR-ABL off TKI: 2 cases of improvement from MMR to deep MR (MR5), and among 4 cases not in MMR at TKI cessation, 1 achieved MMR during pregnancy (Table 2). BCR-ABL rise in 2 or more consecutive measurements, and at least one measurement of rise defined as more than 2-fold increase, was observed in 24 patients. The median BCR-ABL doubling time among 54 such instances in these 24 patients was 18.3 days (range 1.8-306.8). Of 20 cases that lost MMR during pregnancy, 17 met these criterions for BCR-ABL rise; the median doubling time among 40 such instances in these cases was 14.7 days (1.8-306.8). Postpartum (n=48), 34 cases have been retreated to date; 14 others remain off therapy with ongoing deep MR (MR5) in 6 cases, MMR in 6 and BCR-ABL

Description: Introduction. A substantial proportion of patients (pts) affected by Chronic Myeloid Leukemia (CML) achieve complete negativity in Q-RT-PCR. In this situation, as already demonstrated in other STOP trials, it is possible to safely discontinue imatinib treatment but it is still not clear how to discriminate subjects who will relapse. In fact even undetectable BCR-ABL may not equate to eradication of the disease because of the sensitivity of Q-RT-PCR. A new diagnostic method, the digital-PCR (dPCR), able to detect 1 BCR-ABL+ cell out of 107 cells, has been developed. Therefore, dPCR by assessing the presence of minimal residual disease with higher sensitivity, could potentially identify pts in whom CML has been eradicated. Aims. The ISAV study is aimed at validating the capability of dPCR to predict relapses after imatinib discontinuation in CML pts with negative Q-RT-PCR results and to evaluate relapse rate and timing of recurrence, survival and the impact of imatinib treatment on Quality of Life (QoL). Methods. This study involves 15 sites, 10 in Italy and 1 in each of the following countries: Germany, Spain, The Netherlands, Canada and Israel. CML pts (Chronic or Accelerated Phase) under imatinib therapy since more than 2 years and in complete molecular remission (CMR) were eligible. Patients had to be in CMR for at least 18 months (mts), with a minimum of 3 Q-RT-PCR performed at their own sites. After signing the informed consent, blood samples were obtained for dPCR and the pts discontinued imatinib therapy. Standard Q-RT-PCR is performed monthly (mts 1-6) and then bimonthly for 36 mts to assess the maintenance of the molecular remission. The loss of molecular remission is defined as two consecutive positive Q-RT-PCR tests with at least one BCR-ABL/ABL value above 0.1%. Patients losing molecular remission resume imatinib treatment at the same dosage used before interruption. Patients' QoL during imatinib discontinuation/resumption is evaluated through the EORTC QLQ-C30 questionnaire. Results. The study enrolled 112 pts with a median follow-up (FUP) time of 28.0 mts [95% CI: 25.5-30.1]. The 59.3% of pts were male and 37.0% were aged 65 or older; median duration of imatinib treatment was 103.1 mts with median duration of CMR of 25.7 mts before imatinib discontinuation. The cumulative probability of survival is 97.8% [95% CI: 91.4-99.5]. dPCR results showed that 23.1% of pts were positive and 75.9% negative, with a significant Negative Predictive Value ratio (dPCR/Q-RT-PCR) of 1.112 [95% CI: 1.009-1.225]. At 24 mts from imatinib discontinuation, 53 pts (49.1%, 95% CI: 39.3-58.9) of the 108 eligible pts relapsed and resumed imatinib; 73.6% of them relapsed in the first 9 mts and the last relapse occurred 21.8 mts after imatinib discontinuation. A loss of CCyR occurred in 13 pts (34.2% of those tested): 10/13 CCyR losses were recovered, the remaining 3 were not assessed for response. No case of CML progression or resistance to imatinib was observed. After the resumption of imatinib the median time to MMR/CMR was 1.9 [95% CI: 1.2-2.4] mts. Of the 55 not-relapsed pts, 42 (38.9% of the total) regained Q-RT-PCR positivity but never lost MMR. The median time to Q-RT-PCR positivity was 2.9 mts [95% CI: 2.0-3.1] in the relapsed pts and 4.5 mts [95% CI: 2.9-6.9] in pts who developed only PCR positivity. No significant correlation between relapse and previous duration of imatinib treatment, use of interferon, time to CCyR, Sokal score or duration of CMR was identified, while an inverse relationship between pts age and risk of relapse is evident. Moreover, age and dPCR results together can predict the risk of relapse: pts with less than 45 years and with a positive dPCR had the highest risk of relapse (100%) as opposed to pts ≥ 45 years and with negative dPCR (36.1%). The analysis of QoL evidenced a statistically significant improvement in the general well-being and symptoms scales at 1 month after imatinib discontinuation and in particular nausea, diarrhea and fatigue (p

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: Background: Chronic, low-grade adverse events (AEs) are common in CML patients (pts) treated with the BCR-ABL1 tyrosine kinase inhibitor (TKI) imatinib (IM) and may decrease quality of life (Efficace, Blood. 2011;118:4554) and adherence to therapy (Marin, J Clin Oncol. 2010;28:2381). These AEs may result in dose modifications and contribute to suboptimal response. Alternative TKIs are available with the potential to reduce AEs, improve tolerability, and support long-term treatment goals. The second-generation TKI dasatinib (DAS) has demonstrated efficacy in pts previously treated with IM in the CA180-034 trial (Shah, Blood. 2014;123:2317). We present the analysis of CA180-400 (NCT01660906), an open-label, multicenter phase 4 study designed to determine if chronic, low-grade nonhematologic AEs in IM-treated pts improve after switching to DAS. Methods: Adult CML-CP pts who had not failed previous IM therapy (complete hematologic response by 3 mo, partial cytogenetic response [PCyR] by 6 mo, or complete cytogenetic response [CCyR] by 12 mo [Baccarani, Blood. 2013;122:872]) and had a chronic, grade 1/2 nonhematologic IM-related AE persisting for ≥2 mo or recurring ≥3 times in the prior 12 mo, despite best supportive care, were switched to DAS 100 mg once daily until disease progression, treatment failure, unacceptable AE, withdrawal of consent, or study discontinuation at 12 mo. The primary endpoint was the frequency of chronic, grade 1/2 nonhematologic IM-related AEs that decreased in grade or resolved within 3 mo following DAS initiation. Treatment-emergent DAS-related AEs and pt-reported symptom burden using MD Anderson Symptom Inventory (MDASI)-CML symptom severity and interference scores (0-10 scale; 10=worst) were also evaluated 3 mo following the switch to DAS. Results: Thirty-nine pts were enrolled in the trial. Median age was 57 y (range 23-81 y), with 31% ≥65 y. Median duration of prior IM was 47 mo and 49% had received

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: Background and Aims- In Ph+ ALL pts treated with tyrosine kinase inhibitors (TKIs), the likelihood of acquiring TKI-insensitive mutations and the striking incidence of highly resistant T315I and compound mutants underscore the importance of BCR-ABL1 kinase domain (KD) sequence surveillance for timely and rational therapeutic reassessment. We used an amplicon DS strategy of the BCR-ABL1 KD to assess the following issues: i) whether DS allows earlier detection of emerging TKI-insensitive mutations in pts undergoing BCR-ABL1 KD mutation screening for minimal residual disease (MRD) persistence; ii) whether TKI-insensitive low burden mutations can be identified in relapsed pts with negative conventional sequencing results; iii) whether TKI-insensitive low burden mutations are necessary and sufficient to predict for treatment failure in all cases. Methods- This study was conducted in a total of 56 Ph+ ALL pts who received TKI-based therapies at our or collaborating institutions and were referred to our laboratory for MRD follow-up monitoring by RQ-PCR and for BCR-ABL1 KD mutation analysis in case of MRD positivity. These pts were divided into three different cohorts: i) 10 de novo and 24 advanced Ph+ ALL pts who relapsed and developed BCR-ABL1 KD mutations on TKI-based therapy administered 1st-line or for recurrent disease, respectively. To reconstruct the dynamics of mutation emergence, longitudinal re-analysis of monthly-collected samples from the time of hematologic relapse backwards was performed by DS. Whenever samples were available, the analysis was done back to the time of diagnosis (n=10/10) or back to the time of first or former relapse (n=15/24), respectively. Two to 6 samples were analyzed for each pt, for a total of 109 samples. ii) 14 Ph+ ALL pts who were known to be negative for mutations at the time of hematologic relapse as assessed by conventional sequencing. Relapse samples were reanalyzed by DS. iii) 8 Ph+ ALL pts with long-term relapse-free survival despite persistent or intermittent MRD positivity at multiple timepoints. Up to 5 samples were analyzed for each pt, for a total of 28 samples. DS was performed on a Roche GS Junior. Lower mutation detection limit of DS was 1%. Results- In the 34 de novo or advanced Ph+ ALL pts who were known to have acquired TKI-insensitive mutations at the time of relapse on tyrosine kinase inhibitor (TKI) therapy, longitudinal retrospective reanalysis by DS allowed mutation backtracking in 13 (41%) cases. One patient was found to harbour a low burden Y253H at diagnosis. In 3 imatinib (IM)-resistant pts who switched to dasatinib (DAS), a low burden T315I mutation was already detectable at baseline. In the 14 pts with no mutations detectable by conventional sequencing at the time of relapse on IM or DAS, low burden TKI-insensitive mutations were detected by DS in 6 (43%) cases. In 2 cases who had relapsed on DAS, a T315I and an F317L mutation, respectively, were present just below the lower detection limit of conventional sequencing (15.9% and 12.4%, respectively); in the remaining 4 pts, DS identified multiple (2 to 3) low burden mutations, all of which known to confer a moderate to high degree of insensitivity to the ongoing TKI. In the 8 pts with persistently or transiently detectable BCR-ABL1 transcripts at multiple timepoints despite stable hematologic remission, DS detected low burden mutations in 9 samples from 4 pts. However, no mutation known to be truly insensitive to the ongoing TKI could be recognized. Conclusions MRD persistence in Ph+ ALL pts may hide emerging TKI-insensitive BCR-ABL1 KD mutations that DS may identify earlier than conventional sequencing - allowing a greater leeway before overt hematologic relapse occurs; polyclonal resistance sustained by multiple TKI-insensitive low burden mutations may explain relapse in a proportion of cases with unmutated BCR-ABL1 KD sequences as assessed by conventional sequencing; the type of mutation matters: detection of low burden mutations insensitive to the ongoing TKI was always found to predict/correlate with treatment failure. Detection of low burden mutations with low/unknown IC50 might explain low level MRD but does not predict for an impending relapse; MRD-triggered, BCR-ABL1 KD mutation screening by DS may be precious for earlier and more effective use of preemptive rescue therapies. Supported by ELN, AIL, AIRC, FP7 NGS-PTL project, Progetto Regione-Università 2010-12 (L. Bolondi) Disclosures Soverini: Ariad: Consultancy; Bristol-Myers Squibb: Consultancy; Novartis: Consultancy. Abruzzese:BMS, Novartis, Pfizer, Ariad: Consultancy. Baccarani:ARIAD Pharmaceuticals, Inc.: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; PFIZER: 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. Cavo:Onyx: Honoraria; BMS: Honoraria; Novartis: Consultancy, Honoraria; Millenium Pharmaceuticals: Honoraria; Celgene: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Jansenn: Consultancy, Honoraria. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Martinelli:Pfizer: Consultancy; BMS: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; ROCHE: Consultancy; AMGEN: Consultancy; Ariad: Consultancy; MSD: Consultancy.

Description: Introduction: Ponatinib is a potent oral tyrosine kinase inhibitor (TKI) approved for use in patients with refractory CML and Ph+ ALL, including patients with the resistant BCR-ABLT315I mutation. To evaluate whether patient characteristics and outcomes with ponatinib differed by extent of pretreatment with other TKIs, this post hoc analysis examines results among CP-CML patients enrolled in the phase 2 PACE trial (NCT01207440) according to the number of TKIs received prior to study entry. Updated data with 4 years of follow-up will be presented. Methods: Patients with CML or Ph+ ALL who were resistant or intolerant to dasatinib or nilotinib or who had the T315I mutation were enrolled (N=449). Ponatinib was initiated at 45 mg once daily. CP-CML patients were evaluated based on previous treatment with 1, 2, 3, or 4 prior TKIs approved for use in CP-CML (ie, imatinib, dasatinib, nilotinib, and bosutinib). Data reported in this abstract are as of February 2, 2015. Results: Overall, 270 CP-CML patients were enrolled and treated in PACE. Patient characteristics and disposition varied by number of prior TKIs (Table 1). Both median age and median time from diagnosis increased with number of prior TKIs; median dose intensity was highest in patients who had received only 1 prior TKI. The most common reasons for discontinuation across groups were adverse events (AEs) and withdrawal by patient request. Responses by number of prior TKIs are shown in Table 2. Rates of cytogenetic and molecular response to ponatinib were higher with fewer prior TKIs. While the frequency of individual AEs did not follow a consistent trend, the incidence of grade ≥3 AEs appeared to increase with the number of prior TKIs received (68%, 86%, 89%, and 100%, respectively); grade ≥3 AEs in ≥10% of CP-CML patients overall were thrombocytopenia (35%), neutropenia (17%), hypertension (13%), increased lipase (12%), and abdominal pain (10%). A similar frequency pattern was observed for serious AEs, which occurred in 58%, 53%, 62%, and 92% of patients who had previously received 1, 2, 3, and 4 approved TKIs, respectively. Serious AEs in ≥5% of CP-CML patients overall were pancreatitis (7%), angina pectoris (5%), and pneumonia (5%). The frequency of arterial occlusive events (AOEs) was 32% (6/19), 26% (25/98), 28% (39/141), and 42% (5/12) by increasing number of prior TKIs; exposure-adjusted incidence rates of new AOEs were 11.75, 10.4, 12.6, and 33.3 events per 100 patient-years, respectively. Conclusions: With 4 years of follow-up, ponatinib continues to provide benefit to ongoing CP-CML patients in the PACE trial. Analysis by treatment history indicates that patients who had received fewer TKIs prior to study entry appear to exhibit better efficacy and safety profiles. However, treatment decisions should be primarily guided by individual patient and disease factors, including mutation status, and physicians should weigh both the benefits and risks of prescribing ponatinib. Table 1. Patient Characteristics and Disposition by Number of Prior TKIs 1 TKI (n=19) 2 TKIs (n=98) 3 TKIs (n=141) 4 TKIs (n=12) Median age at baseline, years 52 58 63 67 Median time from diagnosis to first dose, years 2.8 5.2 7.9 12.4 Median dose intensity, mg/d 34.0 28.7 29.9 31.0 Mutations detected at baseline, % 68 51 43 75 T315I mutation detected at baseline, % 63 31 16 0 Prior TKI exposure, %, imatinib/dasatinib/nilotinib/bosutinib 68/21/5/5 97/66/36/1 100/96/96/7 100/100/100/100 Remain on study, % 53 48 40 8 Discontinued, % 47 52 60 92 Primary reason for discontinuation, % AE 16 18 17 33 Withdrawal by patient request 5 11 11 25 Disease progression 16 5 13 0 Lack of efficacy 0 2 9 8 Death 0 2 3 17 Othera 11 13 8 8 Median follow-up, months 42.3 42.9 42.1 28.2 aIncludes noncompliance, physician decision, protocol violation, and other reasons Table 2 Responses to Ponatinib by Number of Prior TKIs 1 TKI (n=16a) 2 TKIs (n=98) 3 TKIs (n=141) 4 TKIs (n=12) MCyR 12 (75) 69 (70) 69 (49) 7 (58) CCyR 12 (75) 63 (64) 63 (45) 4 (33) MMR 10 (63) 41 (42) 51 (36) 1 (8) MR4 6 (38) 30 (31) 38 (27) 1 (8) MR4.5 4 (25) 22 (22) 34 (24) 1 (8) All responses are n (%) a16/19 patients were evaluable for efficacy Disclosures Hochhaus: Bristol-Myers Squibb: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; ARIAD: Honoraria, Research Funding. Cortes:ARIAD Pharmaceuticals Inc.: Other: Consulting & Advisory Role, Research Funding. Pinilla-Ibarz:Novartis: Consultancy, Other: Consulting & Advisory Role, Research Funding; ARIAD Pharmaceuticals, Inc.: Consultancy, Other: Consulting & Advisory Role, Research Funding; Teva: Consultancy, Speakers Bureau; Pfizer: Consultancy, Other: Consulting & Advisory Role, Research Funding, Speakers Bureau; BMS: Consultancy, Honoraria, Other: Consulting & Advisory Role, Speakers Bureau. le Coutre:Novartis: Honoraria; BMS: Honoraria; ARIAD Pharmaceuticals Inc.: Honoraria; Pfizer: Honoraria. Paquette:ARIAD Pharmaceuticals Inc.: Honoraria; BMS: Honoraria; Novartis: Honoraria. Chuah:Children International: Honoraria; Novartis: Honoraria; Bristol Meyers Squibb: Honoraria. Nicolini:Ariad Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bristol-Myers Squibb: 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, Research Funding, Speakers Bureau. Apperley:BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; ARIAD: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: 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, Speakers Bureau. Talpaz:Pfizer: Other: CONSULTING OR ADVISORY ROLE; Novartis: Other: CONSULTING OR ADVISORY ROLE; ARIAD Pharmaceutical Inc.: Other: CONSULTING OR ADVISORY ROLE; Pfizer: Other: TRAVEL, ACCOMODATIONS, EXPENSES, Research Funding; Novartis: Other: TRAVEL, ACCOMODATIONS, EXPENSES, Research Funding; ARIAD Pharmaceutical Inc.: Other: TRAVEL, ACCOMODATIONS, EXPENSES, Research Funding; Incyte: Other: TRAVEL, ACCOMODATIONS, EXPENSES, Research Funding; Sanofi: Research Funding. DeAngelo:Incyte: Other: Consulting or Advisory Role; Pfizer: Other: Consulting or Advisory Role; Novartis: Other: Consulting or Advisory Role; BMS: Other: Consulting or Advisory Role; ARIAD Pharmaceuticals Inc.: Other: Consulting & Advisory Role; Amgen: Other: Consulting or Advisory Role. Abruzzese:BMS: Other: Consulting or Advisory Role; ARIAD Pharmaceuticals Inc.: Other: Consulting & Advisory Role; Novartis: Other: Consulting or Advisory Role; Pfizer: Other: Consulting or Advisory Role. Rea:Bristol-Myers Squibb: Honoraria; Novartis: Honoraria; Pfizer: Honoraria; Ariad: Honoraria. Baccarani:Pfizer: Other: Travel, Accommodations, Expenses; BMS: Other: Travel, Accommodations, Expenses; Novartis: Other: Travel, Accommodations, Expenses; ARAID Pharmaceutical Inc.: Other: Consulting or Advisory Role, Speakers Bureau; Pfizer: Honoraria, Other: Consulting or Advisory Role, Speakers Bureau; Novartis: Honoraria, Other: Consulting or Advisory Role, Speakers Bureau; BMS: Honoraria, Speakers Bureau; ARIAD Pharmaceutical Inc.: Other: Travel, Accommodations, Expenses. Muller:ARIAD Pharmaceuticals Inc.: Honoraria, Other: Consulting & Advisory Role, Research Funding; Novartis: Honoraria, Other: Consulting or Advisory Role, Research Funding; BMS: Honoraria, Other: Consulting or Advisory Role, Research Funding. Lustgarten:ARIAD Pharmaceuticals Inc.: Employment, Equity Ownership, Other: Stock. Conlan:ARIAD Pharmaceuticals Inc.: Other: Stock. Rivera:ARIAD Pharmaceuticals Inc.: Employment, Other: Full-time Employee & Shareholder (self-managed). Guilhot:Celgene: Consultancy, Other: CONSULTING OR ADVISORY ROLE; Pfizer: Honoraria; Novartis: Honoraria, Other: TRAVEL, ACCOMODATIONS, EXPENSES. Deininger:Incyte: Consultancy, Honoraria, Other: Consulting or Advisory Role; Pfizer: Consultancy, Honoraria, Other: Consulting or Advisory Role; ARIAD Pharmaceutical Inc.: Consultancy, Honoraria, Other: Consulting or Advisory Role; Gilead: Research Funding; Celgene: Research Funding; Novartis: Consultancy, Honoraria, Other: Consulting or Advisory Role, Research Funding; BMS: Consultancy, Honoraria, Other: Consulting & Advisory Role, Research Funding. Hughes:Bristol-Myers Squibb: Honoraria, Research Funding; ARIAD: Honoraria, Research Funding; Novartis: Honoraria, Research Funding. Shah:Pfizer: Research Funding; Bristol-Myers Squibb: Research Funding; Plexxikon Inc.: Research Funding. Kantarjian:Novartis: Research Funding; BMS: Research Funding; Pfizer: Research Funding; Amgen: Research Funding.