Abstract: Introduction: Early prediction of outcome using response-related predictive landmarks has become a major paradigm in the clinical management of chronic myeloid leukemia (CML). Several studies have shown the predictive impact of 10% BCR-ABLIS at 3 and 6 months for different tyrosine kinase inhibitors. The question, which landmark should define treatment failure and determine treatment intervention has been discussed vividly. However, an objective analysis of quality criteria for different early prognostic landmarks is lacking up to now. Here we compare sensitivity, specificity and the proportion of later disease progressions predicted by 3-month and 6-month landmarks in imatinib-treated patients of the CML-study IV. Methods: A total of 1,303 newly diagnosed patients were assigned to an imatinib-based treatment arm of CML-Study IV by April 2010. Median follow-up was 7.1 years. The number of molecular assessments was as follows: n=789 (at 6 months), n=692 (at 3 months) and n=301 (at 3 months and at diagnosis, without pretreatment). Gene expression levels were determined by quantitative RT-PCR. At 3 and 6 months, a BCR-ABL ratio was calculated using ABL as reference gene and standardized according to the international scale (BCR-ABLIS). In addition, at 3 months and at diagnosis a BCR-ABL ratio was calculated using beta-glucuronidase (GUS) as reference gene in order to ensure linearity of measurement at diagnosis. The log reduction at 3 months was calculated from the BCR-ABL ratio at 3 months and at diagnosis. Due to the time-dependent nature of censored survival data, the sensitivity and specificity at eight years were calculated using the method by Heagerty et al. (Biometrics 2000). Overall survival (OS) is defined by the absence of death from any reason, progression-free survival (PFS) is defined as survival in the absence of progression to accelerated or blastic phase. Landmark analyses were performed to compare survival outcomes according to Kaplan-Meier. Results:Comparing the 10% BCR-ABLIS landmark at 3 and 6 months, 8-year OS and PFS rates are equal or comparable (table). In contrast, sensitivity and specificity differ substantially with an advantage in favor of sensitivity for the 3-month landmark and in favor of specificity for the 6-month landmark. This difference is paralleled by a smaller proportion of high-risk patients and less progressions identified by the 6-month landmark. From a clinical point of view the 6-month landmark is not only less than half as sensitive, moreover a treatment intervention at 6 months might also prevent less progressions due to the delay of 3 months. The half-log reduction landmark at 3 months is as sensitive as 10% BCR-ABLIS at the same time. However, it shows improved specificity and defines the smallest proportion of high-risk patients. Conclusion: The 10% BCR-ABLIS landmark, which is currently defining treatment failure at 6 months according to European LeukemiaNet (ELN) criteria, fails to detect the majority of patients with later disease progression. Less than a half-log reduction of individual baseline BCR-ABL transcript levels at 3 months on treatment identifies patients with later progressions as sensitive but with higher specificity as compared to 10% BCR-ABLIS. Abstract 156. Table Prognostic landmark 8-year OS (%) 8-year PFS (%) P-value for PFS Sensitivity to predict progression (%) Specificity to predict progression (%) High-risk patients Disease progressions classified as high-risk / total 3 months (n=692) 10% BCR-ABLIS 88 vs. 96 82 vs. 90 0.001 41.1 74.6 191 (28%) 32/74 (43%) 6 months (n=789) 10% BCR-ABLIS 88 vs. 96 84 vs. 95 0.001 18.2 93.8 95 (12%) 17/74 (23%) 1% BCR-ABLIS 90 vs. 97 89 vs. 97 〈 0.001 39.6 68.6 291 (37%) 46/74 (62%) 3 months (n=301) 0.5-log reduction 81 vs. 95 75 vs. 94 〈 0.001 42.6 86.9 48 (16%) 10/24 (42%) Disclosures Hanfstein: Novartis: Research Funding; Bristol-Myers Squibb: Honoraria. Hehlmann:Novartis: Research Funding; Bristol-Myers Squibb: Research Funding. Saussele:Novartis: Honoraria, Research Funding, Travel Other; Bristol-Myers Squibb: Honoraria, Research Funding, Travel, Travel Other; Pfizer: Honoraria, Travel, Travel Other. Schnittger:MLL Munich Leukemia Laboratory: Equity Ownership. Neubauer:MedUpdate: Honoraria, Speakers Bureau. Kneba:Novartis: Consultancy, Equity Ownership, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Pfirrmann:Novartis: Consultancy; Bristol-Myers Squibb: Honoraria. Hochhaus:Novartis: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria; ARIAD: Honoraria, Research Funding; Pfizer: Consultancy, Research Funding. Müller:Novartis: Honoraria, Research Funding; Bristol Myers Squibb: Honoraria, Research Funding; ARIAD: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding.

Abstract: There is a strong negative association between comorbidities at diagnosis and overall survival. There is no negative effect of comorbidities on remission rates and progression to advanced phases in CML.

Abstract: Tyrosine kinase inhibitors (TKI) have changed the natural course of CML. Their efficacy leads to normal life expectancy in the vast majority of patients. With the advent of 2nd generation TKI and the now available choice of drugs, safety issues have gained interest. We have used the randomized CML-Study IV for a long-term safety evaluation of imatinib. Study and Patients CML-Study IV comprises 1551 patients randomized to 5 treatment arms with 3 imatinib-based combinations and 2 different imatinib-dose schedules. 1501 patients have received imatinib and were evaluable. Median age at diagnosis was 53 years, 88% were EUTOS low risk. At the last evaluation (04/11/2013) 1003 patients still received imatinib, 164 had died, 275 were switched to a 2nd generation TKI, 106 were transplanted. The longest observation time was 11.5 years, the median observation time was 6.5 years, with a 10-year survival probability of 84 %. The median time to imatinib discontinuation has not been reached after 10.2 years. 80 patients are under observation for more than 10 years, 18 of these have discontinued imatinib. Out of the 1501 patients that had received imatinib, 1375 patients received imatinib as first-line treatment and had a sufficient documentation of treatment. Methods AE were reported at each follow-up visit. The CTC AE list of the NCI was used for coding of AE and severity grading. Additionally, for detection of hematologic AE lab results were screened for deviations from reference ranges. The AE were analyzed according to the “as treated” principle, using Kaplan-Meier curves (virtually no competing risks, almost all patients died after end of imatinib treatment). Only the first event of the respective type was considered. All analyses started at the first day of imatinib treatment and were censored when the patient discontinued imatinib, received another treatment or died. To assess the differences between men and women, Cox models were estimated. Results In 1137 out of 1375 patients (83%) non-hematologic AE (5160 singular events) were reported during imatinib treatment (all grades), in 322 grade 3/4 AE (23%) (645 singular events). At 3 years, probability of a non-hematologic AE (any grade) was already 76% (95%-CI: 73-79%), at 6 years 85% (95%-CI: 82-88%) and at 8 years 91% (Fig.1). The probability of grade 3/4 non-haematologic AE was 38% (95%-CI: 34-42%) at 6 years and 43% (CI: 37-48%) at 8 years. 156 patients reported hematologic grade 3/4 AE (187 singular events).The probability of hematologic grade 3/4 AE was 17% at 6 years (95%-CI: 15-21%) with most events observed during the first year of treatment (probability after one year 10.5%). The most frequently reported non-hematologic AE (all grades, any time) were gastrointestinal (6-year-probability 52%, 95%-CI: 48-56%), fluid overload or edema (6y-prob. 45%, 95%-CI: 40-49%), rash (6y-prob. 32%, 95%-CI: 28-36%), myalgia or arthralgia (6y-prob. 30%, 95%-CI: 27-34%), fatigue (6y-prob. 26%, 95%-CI: 22-29%), flu-like symptoms (6y-prob. 22%, 95%-CI: 19-26%), infections (6y-prob. 24%, 95%-CI: 20-28%) and neurological symptoms (6y-prob. 26%, 95%-CI: 22-29%). AE probability profiles over time have been generated for each AE (Figs. 2-3). For women the risk for non-hematologic events was increased 1.35-fold (95% CI: 1.18-1.55) for all grades (Figs. 1-3) and 1.13-fold (95% CI: 0.91-1.41) for grade 3/4, and 1.26-fold (95% CI: 0.91-1.71) for grade 3/4 hematologic AE. In 5 patients peripheral arterial occlusive disease grade 2 or 3 was reported, but none could be clearly assigned to imatinib (vascular risk profile of one patient incompletely reported). A definite association between any AE and death was not found. Conclusion As AE by definition may or may not be considered related to the medical treatment an exact assessment of the safety of imatinib is difficult. Most AE were recorded during the first three years with decreasing frequency later on. The increased AE risk in women was mostly grade 1/2 and is commonly seen also in other treatment areas. Given that no imatinib-related death was recorded and that grade 3/4 AE could typically be properly treated we consider imatinib as a safe, comparably well tolerated TKI even after prolonged treatment. After 10 years imatinib continues to be an excellent choice for the treatment of CML in most patients. Disclosures: Hehlmann: Novartis: Research Funding; BMS: Consultancy, Research Funding. Hochhaus:Novartis: Consultancy, Honoraria, Research Funding, Travel Other; BMS: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Ariad: Consultancy, Honoraria. Müller:Novartis: Honoraria, Research Funding, Speakers Bureau; BMS: Honoraria, Research Funding; Ariad: Honoraria. Saussele:Novartis: Honoraria, Research Funding, Travel Other; BMS: Honoraria, Research Funding, Travel, Travel Other; Pfizer: Honoraria.

Abstract: Background: In the current ELN recommendations (Baccarani et al., Blood 2013) the optimal time point to achieve major molecular remission (MMR) is defined at 12 months after diagnosis of CML. MMR is not a failure criterion at any time point leading to uncertainties when to change therapy in CML patients not reaching MMR after 12 months. Aims: We sought to evaluate a failure time point for MMR using data of the CML-Study IV, a randomized five-arm trial designed to optimize imatinib therapy alone or in combination. In addition the optimal time-point to achieve a MMR should be evaluated. Methods: Patients with valid molecular analysis on MR4 level were divided randomly into a learning (LS) and a validation sample (VS). For the LS, MR2 (defined as BCR-ABL 〈 1% which corresponds to complete cytogenetic remission (Lauseker et al. 2014)), MMR and deep molecular remission levels (MR4 or deeper) monthly landmarks were defined between one and five years after diagnosis. A patient was considered to be in MR2, MMR or MR4 from the first diagnosis of the corresponding remission level and could only change to a higher level of response. Patients were censored after SCT. The best prediction time was found via dynamic prediction by landmarking (van Houwelingen, Scand J Stat 2007). For the failure time point analysis, for each of the resulting 48 landmarks, a Cox model was used to define the time to progression with age and EUTOS score as additional prognostic factors. Additionally, the regression coefficients of the model of one landmark were converted to hazard ratios (HR) and treated as dependent on the HRs of the other landmarks, using a cubic smoothing function (see Fig 1). The minimum of this function was considered to be the optimal landmark point for the prediction of progression-free survival (PFS). For the calculated time point, landmark analysis for probability of PFS (defined as appearance of accelerated phase, blast crisis or death) was performed in the VS. For the evaluation of the optimal time point of achieving a MMR the same analysis was done from 0.25 to 5 years to define the time to MR4 or deeper. Results: 1551 patients were randomized from 2002 to 2012, 1358 had a valid molecular analysis on the MR4 level. 114 patients in the imatinib after IFN arm and 16 patients with missing EUTOS score were excluded. Of the 1228 evaluable patients two thirds were randomly allocated to the LS (n=818) and one third to the VS (n=410). Percentage of patients of the LS in MR2, MMR and MR4 or deeper at one year was 28%, 29% and 14%, and at 5 years 5%, 21% and 71%, respectively. Monthly time points in between were also calculated. 44 patients of the LS reached MMR on second generation tyrosine kinase inhibitors.. The minimum of the cubic function of the HRs was found for MMR at 2.34 years with a HR of 0.25 (compared to patients without any remission) and 0.75 compared to those in MR2. For MR4 or deeper no exact time point could be calculated (see Fig. 1), although it was shown that the risk of progression was slightly lower for MR4 than for MMR. Since the time interval for molecular evaluation in the study is 3 months, the validation was done with 2.25 instead of 2.34 years. 364 of the 410 of the VS were still at risk at this time point and evaluable. A significant PFS advantage for patients in MMR could be demonstrated (p=0.018). At 8 years, the probability of PFS for patients in MMR was 90.8% (confidence interval 87.0-93.7%) vs. 80.5% (confidence interval 70.2-88.6%) for patients not in MMR (see Fig 2). For the optimal MMR analysis no singular time point could be calculated as the earlier a MMR was reached the higher was the chance to achieve a MR4. Conclusions: In this model, an optimal time point to predict PFS in patients with MMR was defined at 2.25 years after diagnosis and could be validated as significant. Nevertheless, patients being in MMR had a lower risk of progression than patients not being in MMR on any other time point as well. With this model we can give hints when to define MMR as failure and a change in therapy should be considered. Despite this we should keep in mind that the earlier MMR was achieved the higher was the chance to achieve deep molecular response later during therapy. Figure 1 Cubic smoothing function of the HR to predict PFS with confidence intervals Figure 1. Cubic smoothing function of the HR to predict PFS with confidence intervals Figure 2 Landmark analysis at 2.25 years for PFS of the VS Figure 2. Landmark analysis at 2.25 years for PFS of the VS Disclosures Saussele: Novartis: Honoraria, Research Funding, Travel Other; Bristol-Myers Squibb: Honoraria, Research Funding, Travel, Travel Other; Pfizer: Honoraria, Travel, Travel Other. Hehlmann:Bristol-Myers Squibb: Research Funding; Novartis: Research Funding. Schnittger:MLL Munich Leukemia Laboratory: Equity Ownership. Hanfstein:Novartis: Research Funding; Bristol-Myers Squibb: Honoraria. Neubauer:MedUpdate: Honoraria, Speakers Bureau. Kneba:Novartis: Consultancy, Equity Ownership, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Pfirrmann:Novartis: Consultancy; Bristol-Myers Squibb: Honoraria. Hochhaus:Novartis: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria; ARIAD: Honoraria, Research Funding; Pfizer: Consultancy, Research Funding. Müller:Novartis: Honoraria, Research Funding; Bristol Myers Squibb: Honoraria, Research Funding; ARIAD: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding.

Abstract: In acute leukemias, specific cytogenetic aberrations frequently correlate with myeloid or lymphoid phenotype of blasts and influence risk stratification. In chronic myeloid leukemia (CML) blast crisis (BC) it is not clear whether myeloid or lymphoid phenotype of blasts could be distinguished by specific chromosomal aberrations and have prognostic value. At diagnosis of CML, major route additional cytogenetic aberrations (ACA) like +8, i(17)(q10), +19, +der(22)t(9;22)(q34;q11) and minor route ACA like -X, del(1)(q21), del(5)(q11q14), +10,-21, resulting in an unbalanced karyotype have been described to adversely affect outcome. Patients with minor route ACA (for example reciprocal translocations other than the t(9;22)(q34;q11) (e.g. t(1;21), t(2;16), t(3;12), t(4;6), t(5;8), t(15;20)) resulting in a balanced karyotype did not show differences in overall survival and progression free survival compared to patients with the standard translocation, a variant translocation or the loss of the Y chromosome. Aim of this study was to analyze the impact of the phenotype (myeloid or lymphoid) on time to BC and on cytogenetic pattern. Methods 73 out of 1524 evaluable patients (4.8%) randomized until March 2012 to the German CML-Study IV (a 5-arm trial to optimize imatinib therapy) progressed to BC. Cytogenetic data of 23 out of 32 patients with myeloid BC and 14 out of 21 patients with lymphoid BC were available. In 15 patients, cytogenetic analysis were missing whereas 2 and 3 patients had megakaryoblastic and mixed phenotype, respectively and were not considered in this analysis. Karyotypes of lymphoid and myeloid BC were divided in major route and minor route ACA and balanced and unbalanced karyotypes. Categorical covariates were compared with Fisher’s exact test, while continuous covariates were compared with the Mann-Whitney-Wilcoxon test. Survival probabilities after BC were compared using the log-rank test. Results Out of 23 patients with myeloid BC, 14 (61%) had major route unbalanced ACA (n=10) or minor route unbalanced ACA (n=4), 4 had minor route balanced ACA and 5 patients had the translocation t(9;22)(q34;q11) or a variant translocation t(v;22) without ACA.13 out of 14 (93%) patients with lymphoid BC had major route unbalanced (n=10) or minor route unbalanced ACA (n=3) and 1 had the standard translocation t(9;22)(q34;q11) only. Between myeloid and lymphoid BC, the difference in the distribution of unbalanced ACA was apparent, but not statistically significant (p=0.06). The most frequently observed major route ACA was trisomy 8 in both groups (7 vs. 6), +der (22)t(9;22)(q34;q11) was more frequently found in myeloid than lymphoid BC (6 vs. 2), +19 was found in both phenotypes (3 vs. 3) whereas an isochromosome i(17)(q10) and an isoderivative chromosome ider(22)t(9;22)(q34;q11) were less frequent and found only in myeloid BC (1 for each vs 0 for each aberration). In lymphoid BC, 5 of 14 patients (36%) had ACA which involved chromosome 7 (del(7)(q22) and -7) whereas in myeloid BC only 2 patients (9%) had -7 (p=0.08). The balanced karyotype with a translocation t(3;21)(q26;q22) and the translocation t(9;11)(p22;q23) described in acute myeloid leukemia was observed in 3 patients with myeloid CML (2 and 1, respectively) and in none with lymphoid phenotype. No differences were observed in time to BC for patients with lymphoid vs. myeloid BC (p=0.31, median time: 409 vs. 453 days) and survival after onset of BC (p=0.9, median time: 544 vs. 284 days). Conclusions The proportion of unbalanced karyotypes was higher in lymphoid than in myeloid BC. In lymphoid BC alterations of chromosome 7 were more often present whereas +der(22)t(9;22)(q34;q11) was observed more frequently in myeloid BC. The reciprocal translocations t(3;21)(q26;q22) and t(9;11)(p22;q23) described in acute myeloid leukemias were only observed in myeloid BC. However these cytogenetic differences do not seem to alter the course of BC. Disclosures: Haferlach: MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Hehlmann:Novartis: Research Funding; BMS: Consultancy, Research Funding. Hochhaus:Ariad: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding, Travel Other. Müller:Novartis: Honoraria, Research Funding, Speakers Bureau; BMS: Honoraria, Research Funding; Ariad: Honoraria. Saussele:Pfizer: Honoraria; BMS: Honoraria, Research Funding, Travel, Travel Other; Novartis: Honoraria, Research Funding, Travel Other.

Abstract: The impact of the type of therapy on cytogenetic evolution in chronic myeloid leukemia (CML) regarding the occurrence of additional cytogenetic aberrations (ACA) at the time point of blast crisis (BC) may be critical. The aim of this analysis was to elucidate whether patients (pts) treated with imatinib (IM) had ACA less frequently than pts treated with BU and other therapies used prior to IM as hydroxyurea (HU) and interferon alpha (IFN). We comparatively analyze the BC karyotype of CML pts treated in consecutive trials of the German CML Study Group (Studies I, II and IV) to answer the following question: Does CML therapy influence the occurrence or even induce ACA or do these alterations rather reflect the natural history and the biology of the disease and are independent of therapy? Materials and methods Cytogenetic data of 157 pts with Philadelphia chromosome and BCR-ABL positive CML in BC were analyzed from a total of 2,380 pts randomized to CML study I (BU vs. HU vs. IFN, recruitment 1983 – 1991), CML study II (IFN + HU vs. HU, recruitment 1991 – 1994), and CML study IV (IM 400 mg vs. IM 800 mg vs. IM 400 mg +IFN vs. IM 400 mg + AraC vs. IM 400 mg after IFN failure recruitment 2002 – 2012). Cytogenetic analysis was reported according to ISCN 2005. ACA were divided into major route (+8, i(17)(q10), +19, +der(22)t(9;22)(q34;q11)) and minor route alterations (reciprocal translocations other than the t(9;22)(q34;q11), e.g. t(1;21), t(2;16), t(3;12), t(4;6), t(5;8), t(15;20) (Fabarius et al., Blood 2011). Confirmatory testing of pairwise comparisons of therapies with regard to their frequency of major ACAs was performed using two-sided chi-square test. To keep the level of significance at 0.05 despite multiple testing, a priori hypotheses were hierarchically ordered: First, frequency of major route ACA of pts on IM was compared with that on BU, then, with HU and with IFN. Next, the comparisons of IFN vs. BU and IFN vs. HU were planned. Cumulative incidences were estimated under consideration of death before BC as a competing risk. Results 115 of 188 pts randomized to BU (CML study I), 117 of 194 pts randomized to HU (CML study I only) and 159 of 360 randomized to IFN-based therapy (CML studies I+II) progressed to BC. Eight-year cumulative incidence probability of BC was 0.63 [95%-confidence interval (CI): 0.56; 0.69], 0.60 [95%-CI: 0.53; 0.66] , and 0.49 [95%-CI: 0.43; 0.54] in pts randomized to BU, HU, and IFN-based therapy, respectively and 0.06 [95%-CI: 0.04; 0.07] in pts on IM (CML-study IV). Three-year survival probabilities after BC were 0.009 [95%-CI: 0.001; 0.043] with BU, 0.017 [95%-CI: 0.003; 0.055] with HU, 0.013 [95%-CI: 0.003; 0.042] with IFN, and 0.252 [95%-CI: 0.157; 0.368] with IM. Cytogenetic data at BC with banding analysis were available from 21 pts on BU, 31 on HU, 56 on IFN and 49 on IM. 81% of pts treated with BU, 52% with HU, 38% with IFN and 55% with IM showed major route ACA. All other pts had minor route ACA or translocation t(9;22)(q34;q11) and variant translocation (t(v;22)) without ACA (Table 1). The difference in major route ACA between BU and IM was significant (p = 0.04, two-sided chi-square test). There was no statistically significant difference in ACA between pts on HU and IFN in comparison to IM. According to the testing order, further comparative testing was not possible. However, the differences of induction of major route ACA between HU and BU and IFN and BU were even more pronounced than the difference between IM and BU. The most frequently observed major route ACA was trisomy 8 in all studies and therapy arms. Conclusions The type of cytogenetic aberrations in CML BC after different therapies is comparable. The characteristic major route ACA after various therapies points to a CML BC-related chromosomal pattern rather than a therapy-induced effect. Pts treated with IM showed a significantly lower rate of major route ACA than BU. IM not only reduces the frequency of BC and increases survival probabilities but appears to moderately change the biology of BC as compared to BU Disclosures: Haferlach: MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Hehlmann:BMS: Consultancy, Research Funding; Novartis: Research Funding. Hochhaus:Pfizer: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Research Funding; Ariad: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding, Travel Other. Müller:Novartis: Honoraria, Research Funding, Speakers Bureau; BMS: Honoraria, Research Funding; Ariad: Honoraria. Kolb:Pierre Fabre, Therakos: Honoraria; Kolb Consulting UG: Consultancy, Equity Ownership. Saussele:BMS: Honoraria, Research Funding, Travel, Travel Other; Pfizer: Honoraria; Novartis: Honoraria, Research Funding, Travel Other.