Abstract: Deep molecular response (MR 4.5 ) defines a subgroup of patients with chronic myeloid leukemia (CML) who may stay in unmaintained remission after treatment discontinuation. It is unclear how many patients achieve MR 4.5 under different treatment modalities and whether MR 4.5 predicts survival. Patients and Methods Patients from the randomized CML-Study IV were analyzed for confirmed MR 4.5 which was defined as ≥ 4.5 log reduction of BCR-ABL on the international scale (IS) and determined by reverse transcriptase polymerase chain reaction in two consecutive analyses. Landmark analyses were performed to assess the impact of MR 4.5 on survival. Results Of 1,551 randomly assigned patients, 1,524 were assessable. After a median observation time of 67.5 months, 5-year overall survival (OS) was 90%, 5-year progression-free-survival was 87.5%, and 8-year OS was 86%. The cumulative incidence of MR 4.5 after 9 years was 70% (median, 4.9 years); confirmed MR 4.5 was 54%. MR 4.5 was reached more quickly with optimized high-dose imatinib than with imatinib 400 mg/day (P = .016). Independent of treatment approach, confirmed MR 4.5 at 4 years predicted significantly higher survival probabilities than 0.1% to 1% IS, which corresponds to complete cytogenetic remission (8-year OS, 92% v 83%; P = .047). High-dose imatinib and early major molecular remission predicted MR 4.5 . No patient with confirmed MR 4.5 has experienced progression. Conclusion MR 4.5 is a new molecular predictor of long-term outcome, is reached by a majority of patients treated with imatinib, and is achieved more quickly with optimized high-dose imatinib, which may provide an improved therapeutic basis for treatment discontinuation in CML.

Abstract: Abstract 3411 Background: Dose of therapy and time to response may be different in the elderly as compared to younger patients with CML. This has been reported previously for interferon α (Berger et al., Leukemia 2003). For imatinib, contradictory results have been presented (Rosti et al. Haematologica 2007, Guliotta et al. Blood 2009). Aims: An analysis comparing dose-response relationship in patients more or less than 65 years (y) of age is warranted. Methods: We analysed the German CML-Study IV, a randomized 5-arm trial to optimize imatinib therapy by combination, dose escalation and transplantation. Patients older and younger than 65y randomized to imatinib 400 mg (IM400) or 800 mg (IM800) were compared with regard to time to hematologic, cytogenetic and molecular remissions, imatinib dose, adverse events (AEs) and overall survival (OS). Results: From July 2002 to April 2009, 1311 patients with Ph+ CML in chronic phase were randomized, 623 patients were evaluable, 311 patients for treatment with IM400 and 312 for IM800. 84 (27%) and 66 (21%), respectively, were older than 65 years. All patients were evaluable for hematologic, 578 (140 〉 65y and 438 〈 65y) for cytogenetic, and 600 (143 and 457, respectively) for molecular responses. Median age was 70y vs. 49y for IM400 and 69y vs. 46y for IM800. The median dose per day was lower for elderly patients with IM800 (517mg vs. 666mg) and the same with IM400 (400mg each). Patients' characteristics at baseline were evenly distributed in all groups regarding gender, follow-up, hemoglobin, platelet count and spleen size. Leukocyte counts were significantly lower in elderly patients (IM400: 50/nl vs. 78/nl, IM800: 36/nl vs. 94/nl). EURO score was different due to age in elderly patients (low risk: IM400: 11% vs. 43%, IM800: 14% vs. 42%; intermediate risk: IM400: 79% vs. 44% and IM800: 73% and 43%). There was no difference in cytogenetic and molecular analyses between treatment groups. With regard to efficacy, there was no difference for older patients in achieving a complete cytogenetic remission (CCR) and major molecular remission (MMR) if IM400 and IM800 were compared together. If treatment groups were analyzed separately, older patients treated with IM400 reached CCR and MMR statistically significant slower than younger patients (CCR: median 14.2 months vs. 12.1 months, p=0.019; MMR: median 18.7 months vs. 17.5 months, p=0.006). There was no difference with IM800 (CCR: median 7.7 months vs. 8.9 months, MMR: median 9.9 months vs. 10.0 months). 3y-OS for older patients 〉 65y was 94.7% and for patients 〈 65y was 96.1%. Some differences were observed in the safety analyses. 530 patients (IM400: 278, IM800: 252) were evaluated on common toxicity criteria (WHO). Some hematologic AEs were documented slightly more often in the elderly than in the younger patients: for IM400 anemia grade 1–2 (60 vs. 42%) and leukopenia grade 3–4 (5.6 vs. 1.4%) and for IM800 anemia grade 1–4 (64 vs.47% and 7.2 vs. 5.7%) and thrombocytopenia grade 3–4 (9.3 vs. 7.1%). Non hematologic AEs were more prominent in IM800 and were mainly gastrointestinal symptoms (IM400: 33 vs. 31%, IM800: 48 and 44%) and edema (IM400: 28 vs. 29%, IM800: 35 vs. 50%). There was no difference for grade 3/4 non-hematological AEs in older patients in both groups. Conclusions: Imatinib 400 mg and 800 mg are well tolerated also in the elderly. The IM800 dosage was more tolerability-adapted for the elderly, but there was no difference in reaching a CCR and MMR in contrast to the IM400 where a significantly slower response was detected in the elderly. Whether this difference is clinically relevant has yet to be determined. Updated results will be presented. Disclosures: Haferlach: MLL Munich Leukemia Laboratory: Employment, Equity Ownership, Research Funding. German CML-Study Group:Deutsche Krebshilfe: Research Funding; Novartis: Research Funding; Roche: Research Funding; BMBF: Research Funding; Essex: Research Funding.

Abstract: Abstract 357 Treatment of CML with imatinib of 400 mg can be unsatisfactory. Treatment optimization is warranted. The German CML-Study group has therefore conducted a randomized study comparing imatinib 800 mg vs 400 mg vs 400 mg + IFN. A significantly faster achievement of MMR at 12 months has been observed with imatinib 800 mg in a tolerability adapted manner and MMR by 12 months has been found to translate into better overall survival. Since stable CMR has been associated with durable off-treatment remissions we sought to analyse the impact of tolerability-adapted imatinib 800 mg on CMR and survival. Standardized determinations of molecular response and evaluation of its impact on outcome are goals of CML-Study IV. CMR4 is defined as a BCR-ABL/ABL ratio of 〈 0,01 on the International Scale. From July 2002 – April 30, 2009 1022 newly diagnosed patients with CML in chronic phase were randomized, 1012 were evaluable (338 with imatinib 800 mg, 324 with imatinib 400 mg, 350 with imatinib plus IFN). Median observation time was 40 months. The median average daily imatinib doses were 628 mg in the 800 mg arm and 400 mg in the 400 mg based arms. The actual median daily doses in the 800 mg arm per 3-months periods were: 555 mg, 737 mg, 613 mg, 600 mg, and 600 mg thereafter, reflecting the run–in period with imatinib 400 mg for 6 weeks in the first period and the adaptation to tolerability from the third 3-months period onwards. Median daily imatinib doses in the 400 mg arms were 400 mg throughout. Adaptation of imatinib dose in the 800 mg arm according to tolerability is reflected by similar higher-grade adverse events rates (WHO grades 3 and 4) with all treatments. Significantly higher remission rates were achieved with imatinib 800 mg by 12 months. The cumulative incidences of CCR by 12 months were 63% [95%CI:56.4-67.9] with imatinib 800 mg vs 50% [95%CI:43.0-54.5] with the two 400 mg arms. The cumulative incidences of MMR by 12 months were 54.8% [95%CI:48.7-59.7] with imatinib 800 mg vs 30.8% [95%CI:26.6-36.1] with imatinib 400 mg vs 34.7% [95%CI:29.0-39.2] with imatinib + IFN. The cumulative incidences of CMR4 compared with the MMR incidences over the first 36 months are shown in Table 1. Imatinib 800 mg shows superior CMR4 rates over the entire 36 months period, CMR4 is reached significantly faster with imatinib 800 mg as compared to the 400 mg arms. The CMR4 rates reach 56.8% by 36 months [95%CI:49.4-63.5] as compared to 45.5% with imatinib 400 mg [95%CI:38.7-51.0] and 40.5% with imatinib plus IFN [95%CI:34.6-46.3] . Most patients have stable CMR4 over the entire period. Time after start of treat-ment (months) Cumulative incidences MMR(%) CMR4 (%) IM400 n=306 D IM800 n=328 D IM400 +IFN n=336 IM400 n=306 D IM800 n=328 D IM400 +IFN n=336 6 8.6 9.5 18.1 9.7 8.4 3 0.7 3.7 1.3 2.4 12 30.8 24.0 54.8 20.1 34.7 7.5 12.3 19.8 7.4 12.4 18 50.3 18.1 68.4 14.3 54.1 21.2 12.2 33.4 9.8 23.6 24 63 13.0 76.0 13.2 62.8 30.7 12.3 43 13 30.0 36 79.3 2.3 81.6 10.9 70.7 45.5 11.3 56.8 16.3 40.5 In summary, superior CMR4 rates are achieved with high-dose imatinib adapted to good tolerability, and more patients in the tolerability-adapted 800 mg arm have stable CMR4 qualifying for treatment discontinuation as compared to the 400 mg based arms. With improved application imatinib remains first choice for early CML. Disclosures: Koschmieder: Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Membership on an entity's Board of Directors or advisory committees. Schnittger:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. German CML-Study Group:Deutsche Krebshilfe: Research Funding; Novartis: Research Funding; Roche: Research Funding; BMBF: Research Funding; Essex: Research Funding.

Abstract: Background Five-year overall survival (OS) of chronic myeloid leukemia (CML) patients treated with imatinib exceeds 90%. With many tyrosine kinase inhibitors (TKI) available as treatment options for CML, the influence of TKI therapy on OS is difficult to define. Comorbidities can complicate randomized trials. Their influence on OS in CML has not been studied so far. Aims We sought to evaluate the influence of comorbidities at diagnosis of CML on remission rates and OS of patients with Philadelphia and/or BCR-ABL positive chronic-phase CML. The CML-Study IV, a randomized five-arm trial designed to optimize imatinib therapy alone or in combination, used very few exclusion criteria as compared to other studies which typically excluded patients with severe illnesses. Methods The age-adjusted Charlson Comorbidity Index (CCI) is the most extensively studied comorbidity index (Charlson ME et al., 1987) and has been validated for long-term studies. The score weighs a) the severity of comorbidities (e.g. one point is allocated to myocardial infarction and diabetes, two points to non-active malignancies) and b) the age of patients (with one point for each decade above 40 years). The CCI at diagnosis was calculated for each randomized patient. For the analyses, patients were grouped into CCI 2, 3-4, 5-6, and ≥7. Performance status was measured by the Karnofsky Score (KS) and patients were grouped into 50-80, 〉 80- 〈 100, and 100. Correlation analyses were performed by the chi-square test. Survival probabilities were calculated by Kaplan-Meier curves. Calculating cumulative incidences, the competing risks progression and/or death were considered. Cox models were estimated for the multivariate analysis to analyse the prognostic influence of the candidate factors age, sex, leukocytes, hemoglobin, EUTOS score, KS, and CCI on OS. Results 1551 patients were randomized from 2002 to 2012, 1524 patients were evaluable. Median follow-up time was 67.5 months. Additional to CML, 521 index comorbidities were reported in 1519 patients resulting in the following CCI groups: i) CCI 2: 589 patients, ii) CCI 3 or 4: 599 patients, iii) CCI 5 or 6: 229 patients, and iv) CCI ≥ 7: 102 patients. Median value of the CCI was 3 (range: 2-12). The distribution of the CCI groups was not different between treatment arms. Most common comorbidities were diabetes (n=106), non-active cancer (n=102), chronic pulmonary disease (n=74), renal insufficiency (n=47), myocardial infarction (n=38), cerebrovascular disease (n=29), congestive heart failure (n=28), and peripheral vascular disease (n=28). Between patients with CCI 2, 3-4, 5-6, and ≥7 no significant differences in remission rates were found neither for time to complete cytogenetic remission (CCR) nor for time to major molecular remission (MMR). Median times to CCR were 12.9, 12.6, 13.7, and 13.1 months and to MMR 17.5, 15.9, 16.5, and 18.1 months, respectively. No differences were observed between the CCI groups for the cumulative incidences of progression. As expected, significant differences in OS according to CCI at diagnosis were observed (s. Fig. 1, p 〈 0.001). Probabilities of OS at 8 years for patients with CCI 2, 3-4, 5-6, and ≥7 were 93.6%, 89.4%, 78.7%, and 45.2%. We found a correlation between CCI and KS (p 〈 0.001). In multivariate analysis CCI (p 〈 0.001), KS (p=0.022), and EUTOS Score (p=0.012) were significant predictors of OS. Hazard ratios for the CCI group 3-4, 5-6, 〉 7 (each vs. 2), were 1.695 (95%-confidence interval, CI 1.066-2.695), 3.231 (CI 1.942-5.376) and 6.495 (CI 3.817-11.111), respectively. Separating the CCI into an age-related part and a comorbidity-related part, the comorbidity-related part was still an important risk factor (Wald test, p=0.002). Conclusions Comorbidities of CML-patients do not seem to have an impact on the success of imatinib treatment. In CML-Study IV, even patients with a considerable comorbidity benefitted from imatinib as the chances to achieve MMR and CCR did not differ from those of healthier CML-patients. Our data also indicate that OS alone is not any more an appropriate measure for the effectiveness of a specific treatment for CML, as TKI have reduced the CML-related lethality to too low levels. Adjusting for comorbidity is essential for a valid comparison and interpretation of OS observed with different TKIs in CML-patients. Disclosures: Saussele: Pfizer: Honoraria; BMS: Honoraria, Research Funding, Travel, Travel Other; Novartis: Honoraria, Research Funding, Travel Other. Hehlmann:BMS: Consultancy, Research Funding; Novartis: Research Funding. Hochhaus:Novartis: Consultancy, Honoraria, Research Funding, Travel Other; BMS: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Ariad: Consultancy, Honoraria. Müller:Ariad: Honoraria; BMS: Honoraria, Research Funding; Novartis: Honoraria, Research Funding, Speakers Bureau.

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: Abstract 67 Dose optimized imatinib (IM) at doses of 400– 800mg has been shown to induce faster and deeper cytogenetic and molecular – responses than standard IM (400mg/day). Since complete molecular remission (CMR 4.5) identifies a subgroup of patients who may stay in remission even after discontinuation of treatment, it was of interest to analyse whether CMR 4.5 is reached faster with dose optimized IM and whether CMR 4.5 correlates with survival. CMR 4 and CMR 4.5 are defined as ≤ 0.01% BCR-ABL IS or ≥ 4. log reduction and ≤ 0.0032% BCR-ABL IS or ≥ 4.5 log reduction, respectively, from IRIS baseline as determined by real-time PCR. CML-Study IV is a five arm randomized study of IM 400 mg vs IM 400 mg + IFN vs. IM 400 mg + Ara C vs. IM after IFN failure vs. IM 800 mg. In the IM 800 arm, a 6 weeks run in period at IM 400 mg was followed by a dose increase to 800 mg and then by a dose reduction according to tolerability. Grade 3 or 4 adverse effects (AE) were to be avoided. From July 2002 to March 2012 a total of 1551 patients with newly diagnosed chronic phase CML were randomized of whom 1525 were evaluable. Median age was 52 years, 88% were EUTOS low risk, 12% high risk, 36% were Euro score low risk, 52% intermediate and 12% high risk, 38% were Sokal low risk, 38% intermediate and 24% high risk. 113 patients were transplanted, 246 received 2nd generation TKI. 152 patients have died, 90 of CML or unknown reasons, 62 of not directly CML-related causes. After a median observation time of 67,5 months 6 years OS was 88.2% and PFS 85.6%. CCR, MMR, CMR 4 and CMR 4,5 were achieved significantly faster with dose optimized IM (400 – 800 mg). No significant differences in remission rates were observed between IM 400 mg and the combination arms IM 400 mg + IFN and IM 400 mg + Ara C, whereas IM after IFN failure thus far yielded significantly slower response rates. After 4 years CCR rates were for IM 400, IM 400 + IFN, IM 400 + Ara C, IM 400 after IFN, and IM 800, 80%, 75%, 73%, 59% and 80%, respectively, MMR rates 84%, 77%, 82%, 61% and 88%, CMR 4 rates 57%, 55%, 55%, 40% and 65%, and CMR 4.5 rates 40%,42%, 42%, 28% and 52%, respectively. CMR 4 was reached after a median of 27 months with IM 800 and 41.5 months with IM 400. CMR 4.5 was reached after a median of 41.5 months with IM 800 and 63 months with IM 400. EUTOS low risk patients reached all remissions faster than EUTOS high risk patients. The differences of CMR 4 rates between IM 800 and IM 400 at 3 years were 13% and at 4 years 8%, and of CMR 4.5 rates at 3 years 10% and at 4 years 13%. Grade 3 and 4 AE were not different between IM 400 and dose optimized IM 800. Independent of treatment approach, CMR 4 and more clearly CMR 4.5 at 3 years predicted better OS and PFS, if compared with patients without CMR 4 or CMR 4.5, respectively. CMR 4 and 4.5 were stable. After a median duration of CMR 4 of 3.7 years only 4 of 792 patients with CMR 4 have progressed. Life expectancy with CMR 4 and 4.5 was identical to that of the age matched population. We conclude that dose optimized IM induces CMR 4.5 faster than IM 400 and that CMR 4 and CMR 4.5 at 3 years are associated with a survival advantage. Dose optimized IM may provide an improved therapeutic basis for unmaintained treatment discontinuation in patients with CML. Disclosures: Hehlmann: Novartis: Research Funding. Müller:Novartis, BMS: Consultancy, Honoraria, Research Funding. Haferlach:MLL Munich Leukemia Laboratory: Equity Ownership. Schnittger:MLL Munich Leukemia Laboratory: Equity Ownership. Hochhaus:Novartis, BMS, MSD, Ariad, Pfizer: Consultancy Other, Honoraria, Research Funding.

Abstract: Abstract 3746 Introduction: The increase of overall survival in chronic myeloid leukemia (CML) requires closer long-term observation in the face of a potential carcinogenicity of tyrosine kinase inhibitors (TKIs). Preclinical studies with imatinib in rats showed neoplastic changes in kidneys, urinary bladder, urethra, preputial and clitoral glands, small intestine, parathyroid glands, adrenal glands, and nonglandular stomach. Two epidemiologic studies on patients with chronic myeloproliferative neoplasms (CMPN) and CML (Frederiksen H et al., Blood 2011; Rebora P et al., Am J Epidemiol 2010) found an increased risk of secondary malignancies compared with the general population independent of treatment. In contrast, in a recent analysis of patients with CML and CMPN treated with TKI (Verma D et al., Blood 2011) a decreased risk of secondary malignancies was reported. Aims: To further elucidate the risk of TKI treated CML patients for the development of secondary malignancies we analysed data of the CML study IV, a randomized 5-arm trial (imatinib 400 mg vs. imatinib 800 mg vs. imatinib 400 mg in combination with interferon alpha vs. imatinib 400 mg in combination with AraC vs. imatinib 400 mg after interferon failure). Patients and methods: From February 2002 to April 2012, 1551 CML patients in chronic phase were randomized, 1525 were evaluable. Inclusion criteria allowed the history of primary cancer if the disease was in stable remission. Forty-nine malignancies were reported in 43 patients before the diagnosis of CML. If relapses occurred within 5 years after diagnosis of primary cancer they were not considered for further analysis. Median follow-up was 67.5 months. Age-standardized incidence rates were calculated from the age-specific rates using the European standard population (1976). Results: In total, 67 secondary malignancies in 64 patients were found in CML patients treated with TKI (n=61) and interferon alpha only (n=3). Twelve of these patients developed neoplasms after diagnosis of a primary cancer before diagnosis of CML, 5 patients with metastases or recurrence of the first malignancy (range of diagnosis 5–19 years after primary cancer). Median time to secondary malignancy was 2.5 years (range 0.1–8.3 years). The types of neoplasms were: prostate (n=9), colorectal (n=6), lung (n=6), non Hodgkin's lymphoma (NHL; n=7), malignant melanoma (n=5), skin tumors (basalioma n=4 and squamous cell carcinoma n=1), breast (n=5), pancreas (n=4), kidney (n=4), chronic lymphocytic leukemia (n=3), head and neck (n=2), biliary (n=2), sarcoma (n=2), and esophagus, stomach, liver, vulva, uterus, brain, cancer of unknown origin (each n=1). With these numbers the age-standardized incidence rates of secondary malignancies in CML patients were calculated: 534 cases per 100,000 for men (confidence interval [350;718]), and 582 for women (confidence interval [349;817] ). The incidence rates of the general population in Germany were 450 and 350 cases, respectively (“Krebs in Deutschland 2007/2008”, 8th ed., Robert Koch Institute, 2012). The incidence rate of NHLs was higher for CML patients than for the general population but this is not significant. Conclusions: In our cohort, the incidence rate of secondary neoplasms in CML patients was slightly increased compared to the general population. The most common secondary malignancies in CML patients under treatment were cancers of the skin, prostate, colon, lung and NHL. Since the occurrence of secondary neoplasia increases over time, long-term follow-up of CML patients is warranted. Disclosures: Müller: Novartis, BMS: Consultancy, Honoraria, Research Funding. Hochhaus:Novartis, BMS, MSD, Ariad, Pfizer: Consultancy Other, Honoraria, Research Funding. Hehlmann:Novartis: Research Funding.

Abstract: Abstract 781FN2 Introduction: Data on second line therapy with second generation tyrosine kinase inhibitors (TKI) in CML treatment were generated mainly from phase II/III industry initiated trials (Review Hehlmann Exp Op. 2011). 24-month overall survival (OS) varies between 88% and 94% after intolerance and/or resistance to imatinib for chronic phase (CP) and between 67% and 72% for accelerated phase (AP) or blast crisis (BC). Intention to treat analyses including outcome of patients after discontinuation of first line therapies have not been available as yet. We thought to evaluate overall and progression-free survival (OS and PFS) of imatinib intolerant vs. resistant patients under second line TKI with long-term follow-up within an investigator initiated trial. Methods: We analyzed data of the German CML study IV, a randomized 5-arm trial to optimize imatinib therapy on an intention to treat basis. According to protocol, follow-up of patients on and after second generation TKI after imatinib intolerance and/or resistance was continued for OS and PFS. Analysis of PFS was only relevant, if intolerance and resistance to imatinib therapy occurred while a patient was still in chronic phase (CP). Patients were censored at the time of allogeneic stem cell transplantation (allo-SCT). Results: From July 2002 to December 2010, 1,502 patients with Philadelphia chromosome and /or BCR-ABL positive CML in CP were randomized. 129 patients of the “imatinib after interferon arm” and 36 other patients had to be excluded (14 due to incorrect randomization or withdrawal of consent, 22 with missing baseline information). 1337 were randomized to primary imatinib treatment (imatinib 400 mg vs. imatinib 800 mg vs. imatinib in combination with either interferon alpha or araC). Of these, 234 (17%) discontinued imatinib therapy. 156 patients were treated with 2nd generation TKI, 61 were directly referred to allo-SCT, 17 patients received other regimens (including interferon alpha only or hydroxyurea). 120 of 156 patients started second generation TKI therapy (nilotinib, n=41, dasatinib, n=75, bosutinib, n=2, nilotinib and dasatinib, n=2) within 3 months after stopping imatinib, received treatment for at least one week and were evaluable for PFS and OS. 36 patients received second TKI later (median 10 months, range 3.5–61.4). Median age was 50 years (range 16–78), 42.5% were female. 48 patients were intolerant, 48 failed imatinib within CP and 24 after loss of CP (accelerated phase, n=10, blast crisis, n=14). Median time to second generation TKI was 17 months (range 1.4–97 months) and median follow-up after start of second-line TKI 31 months (range 0.2–71 months). Risk stratification according to the EUTOS Score was high in 20 patients (17%) and low in 94 patients (78%) and unknown in 6 patients (5%). OS for all 120 patients 3 years after start of second generation TKI was 73%, 96% for intolerant and 80% for resistant patients in CP and 19% for resistant patients in advanced disease (s. Fig. 1). According to EUTOS score, 3-year OS was 78% for low and 56% for high risk patients. Probability of PFS of the 96 patients in 1st CP after 3 years was 96% for intolerant and 76% for resistant patients. After 2nd generation TKI, 18 patients received an allo-SCT: all were in CP, 2 patients after imatinib intolerance, 16 patients after imatinib resistance. Conclusion: Survival on second generation TKI is high for imatinib intolerant patients in first CP but much lower for resistant patients in first CP or for patients with advanced disease phases. Alternative treatment strategies are warranted for these patient groups. Disclosures: Krause: Micromet: Research Funding. Kneba:Hoffmann La Roche: Honoraria. Hochhaus:Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Ariad: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. German CML Study Group:Deutsche Krebshilfe: Research Funding; Novartis: Research Funding; BMBF: Research Funding; EU: Research Funding; Roche: Research Funding; Essex: Research Funding.

Abstract: Abstract 1681 Introduction: The prognostic impact of different levels of molecular remission (BCR-ABL transcript expression according to International Scale, IS) at various time points on survival under imatinib treatment is still unclear. Whereas recently published data from the IRIS trial described relevant milestones at 6, 12, and 18 months for event-free and progression-free survival (PFS; Hughes et al., Blood 2010), little is known about an association of molecular response with overall survival (OS). The aim of this evaluation of the German CML Study IV was to elucidate the risk of disease progression and death as a function of the depth of molecular response in order to provide guidance in the interpretation of BCR-ABL levels in the clinical setting. Methods: 1,340 patients (median age 52 years, range 16–88, 60% male) were recruited into the randomized German CML Study IV and treated with an imatinib-based therapy as follows: imatinib 400 mg/d, n=381; imatinib 800 mg/d, n=399; imatinib 400 mg/d + interferon alpha, n=402; imatinib 400 mg/d + low-dose cytarabine, n=158. A total of 1,262 patients with typical b2a2 and b3a2 BCR-ABL transcripts were evaluable. Molecular responses were assessed in 811, 764, 671, and 619 patients at 6, 12, 18, and 24 months, respectively. Disease progression was defined as accelerated phase or blastic phase, or death from any reason. Landmark analyses and log-rank tests for OS and PFS were performed according to the achievement of different BCR-ABL response levels at different time points. Results: Patients were grouped according to the degree of molecular response ( 〈 0.1%, 0.1%-1%, 1%-10%, 〉 10% BCR-ABL IS) at each of the 4 time points and evaluated for 5-year OS and PFS. Estimated 5-year OS for the different molecular response categories was: 97% vs 96% vs 90% vs 88% (6 months, p=0.009); 96% vs 95% vs 89% vs 69% (12 months, p 〈 0.001); 98% vs 97% vs 92% vs 66% (18 months, p 〈 0.001); 97% vs 96% vs 96% vs 68% (24 months, p 〈 0.001). Applying the 4 response categories revealed estimated 5-year PFS of 97% vs 96% vs 91% vs 86% (p=0.004) at 6 months, 97% vs 92% vs 89% vs 72% (p 〈 0.001) at 12 months, 99% vs 95% vs 90% vs 77% (p 〈 0.001) at 18 months, and 97% vs 97% vs 93% vs 65% (p 〈 0.001) at 24 months (s. Table). Conclusions: Faster and deeper response to imatinib-based treatment revealed to be associated with improved overall and progression-free survival. Inferior OS and PFS can be deducted from the synopsis of BCR-ABL expression and treatment duration, e.g. 〉 1% BCR-ABL IS at 6 months or 12 months might be, and 〉 10% BCR-ABL IS should be a trigger for a treatment change. Thereby this analysis might provide decision guidance for alteration or continuation of primary imatinib treatment. Disclosures: Schnittger: Münchner Leukämie Labor: Equity Ownership. German CML Study Group:EU: Research Funding; BMBF: Research Funding; Novartis: Research Funding; Deutsche Krebshilfe: Research Funding; Roche: Research Funding; Essex: Research Funding.