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F e r r a t a S t o r t i F o u n d a t i o nMPLW515 mutated patients is given in Table 1. In the total cohort with JAK2V617wt ET, any MPLW515 mutation was detected in 19 out of 324 patients (5.9%).In 104 JAK2V617wt PMF, a total of 10 MPLW515 mutations was detected (9.6%). In contrast, in the JAK2V617F mutated cases (32 ET; 89 PMF), no MPLW515 mutation was detected. Sequencing of the 35 MPLW515 mutations revealed four different MPLW515 subtypes: 20 patients had a W515L mutation, 13 a W515K, one case showed a so far not described W515A mutation leading to a tryptophane to alanine exchange, and another case a novel W515R associated to a tryptophane to arginine exchange ( Figure 1). Although the functional relevance of these two new mutations still has to be evaluated, it has to be hypothesized that the replacement of a large amino acid by a smaller one probably alters the protein structure in both novel mutation subtypes. Mutation/wild type ratios of greater than 1.0 indicated that at least some cells in the respective patient showed loss of the wildtype allele (LOH). Such high mutation ratios were detected in 13/35 (37%) mutated cases. Eight of these cases with high ratios were at advanced stage with a disease history of 2-9 years. Mutation ratios greater than 1% for the W515 were more frequent in PMF/s-AML following PMF (6/8 cases; 75%) when compared to ET (7/26; 27%) (Online Supplementary Table S1a). The mutation/wild type ratios in the remaining 22 patients were between 0.1 and 0.9% (median: 0.3%) (Online Supplementary Table S1b). Based on the applied method, cells with LOH could not be excluded in these low level cases because unapparent homozygousity based on dilution of homozygous cells with wild type cells may be present. However, the low level cases at least had less cells with LOH and thus the ratios may be important. This allows the hypothesis that higher proportions of W515 mutated alleles in total could indicate progression of disease. High mutation ratios were more frequent in the W515K (9/13; 69%) than in W515L (3/20; 15%) (p=0.034) corresponding to the results of Vannucchi et al. 7 and Beer et al. 8 Thus, the W515K mutation seems more often associated with loss of the wildtype allele. Karyotypes were available in 12 MPLW515 mutated cases. Eleven had a normal karyotype; one case had a del(5)(q14q34) and a del(13)(q12q22). It is remarkable that at least at the microscopic level, no LOH of chromosome 1p, where MPL is located, was detectable. This issue has to be investigated with more sophisticated techniques like SNP-array analyses.The frequency of the MPLW515 mutation in our cohort corresponded to previous studies with 5.3% in the JAK2V617wt ET and 9.6% in JAK2V617wt PMF.1,2 In contrast to previous findings, in our small cohort of 121 JAK2V617F mutated patients with ET and PMF there was no case with an MPLW515, whereas others found such a coexistence in up to 22% of MPL mutated MF cases. 1,3,9 Finally, the W515 mutations have so far been identified in ET and PMF only.1 Based on the new potential of...

Introduction: For physically fit CLL pts with low comorbidity burden FCR is the standard frontline regimen in advanced CLL. The CLL10 study, an international phase III study evaluated the efficacy and tolerance of BR in comparison to FCR in frontline therapy of fit pts without del(17p). Methods and Patients: 158 sites in five countries (Germany, Austria, Switzerland, Denmark and Czech Republic) registered 688 CLL pts for central screening including immunophenotyping, FISH, comorbidity burden and renal function. 564 CLL pts with CIRS score ≤ 6, creatinine clearance > 70 ml/min and without del(17p) were enrolled between 10/2008 and 6/2011. Pts were randomly assigned 1:1 to receive 6 courses of FCR (N= 284; F 25mg/m2 i.v. d1–3, C 250 mg/m2 i.v. d1–3, R 375 mg/m2 i.v. d 0 at first cycle and 500 mg/m2 d1 all subsequent cycles; q 28 days) or BR (N=280; B 90mg/m² i.v. d1+2, R 375 mg/m2 i.v. d 0 at first cycle and 500 mg/m2 d1 all subsequent cycles; q 28 days). A general prophylactic use of antibiotics or growth factors was not recommended. Three patients (2 FCR, 1 BR) were excluded because of deferred treatment. The median CIRS score was 2. There was no difference in median age (61.6 years (yrs) for all pts), but a significantly higher proportion of pts ≥ 70 yrs was included in the BR arm (22% vs 14%, p=0.020). Binet A was present in 22%, Binet B in 38 % and Binet C in 40 %. Unmutated IGHV status was not balanced between both groups (68% in BR versus 55% in FCR arm; p=0.003). All other characteristics showed no differences. The mean number of administered FCR courses was 5.27 courses vs 5.41 BR course (p=0.017). Results: The median observation time for all patients was 35.9 months (mo). 547 pts (FCR 274 ; BR 273) were evaluable for response and all pts (282 FCR ; 279 BR) included for progression-free survival (PFS) and overall survival (OS) analysis. The overall response rate in both arms was 97.8% (p=1.0). The complete response (CR) rate according to IWCLL and confirmed by central bone marrow immunohistology was 40.7% with FCR compared to 31.5% with BR (p=0.026). Four-colour-flow MRD data from peripheral blood (sensitivity 10-4) were available from 355 pts (185 FCR; 170 BR) at final staging. In the FCR arm 74.1% and 62.9% in the BR arm respectively of all evaluated pts were MRD negative (p=0.024). Bone marrow samples, available in 129 FCR and 98 BR pts, were MRD negative in 58.1% and 31.6% of pts, respectively (p<0.001). At 12 mo follow-up 58.2% of the pts in the FCR arm (46/79) were still MRD negative in comparison to 26.3% (20/76) after BR (p<0.001). At 18 mo there were 53.8% (35/65) MRD negative cases versus 24.6% (16/65; p=0.006). Median PFS was 53.7 mo in the FCR arm and 43.2 mo in the BR arm (HR=1.589, 95% CI 1.25-2.079; p=0.001). While PFS was statistically not significant different between both arm in pts with mutated IGHV, pts with unmutated IGHV status had a median time to progression of 43.9 mo after FCR compared to 34.0 mo after BR (p=0.015). Physically fit subgroups (CIRS max 3, only one CIRS item, age < 65 yrs) benefited most from FCR therapy. The difference in PFS was statistically not significant between both arms in pts ≥ 65 years, CIRS 4-6 or > 1 CIRS item. Multivariate analysis identified treatment arm, age ≥ 65 yrs, male sex, high serum TK, del(11q), absence of del(13q) and IGHV status as independent prognostic factors for PFS. No difference in OS was observed (at 36 mo 90.6% for FCR vs 92.2% for BR; HR=1.030, 95% CI 0.618-1.717; p=0.910). For OS male gender, age ≥ 60 yrs, high serum TK and IGHV status were assessed as independent prognostic factors. Severe neutropenia was more often observed in the FCR arm (87.7% vs 67.8%, p<0.001), but no significant difference in the incidence of anemia (14.2% vs. 12.0%; p=0.46) or thrombocytopenia (22.4% vs 16.5%; p=0.096) was documented. Severe infections occurred significantly more frequent (39.8% vs 25.4%, p=0.001) in the FCR arm during treatment phase until 6 months follow-up, especially in older pts (48.4% vs 26.8%; p=0.001). Treatment related mortality was 3.9% (FCR) and 2.1% (BR), respectively. Conclusion: The final analysis of the CLL10 study shows that FCR remains the standard therapy in very fit CLL patients, because it yields higher CR rates, more MRD negativity and longer PFS in comparison to BR. However, in elderly fit pts high toxicity rates and infection rates result into dose reductions leading to similar efficacy between both arms. Elderly fit pts or pts with previous infections might benefit from BR as alternative regimen. Disclosures Eichhorst: Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding, Travel grant Other; Mundipharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Travel grant, Travel grant Other; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy. Off Label Use: The Combination of Bendamustine and Rituximab is not approved for frontline chemoimmunotherapy of CLL. Fink:Celgene: Other. Maurer:Mundipharma: Travel grant Other. Kiehl:Roche: Membership on an entity's Board of Directors or advisory committees. Gregor:Roche: Consultancy, Honoraria; Mundipharma: Consultancy, Honoraria. Trneny:Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Fischer:Roche: Other. Döhner:Roche: Research Funding. Kneba:Roche: Consultancy, Research Funding; Mundipharma: Consultancy, Research Funding. Wendtner:Mundipharma: Consultancy, Honoraria, Research Funding; Hoffmann-La Roche: Consultancy, Honoraria, Research Funding. Klapper:Hoffmann-La Roche: Research Funding; Takeda/Millenium: Research Funding. Kreuzer:Roche: Consultancy, Research Funding; Mundipharma: Consultancy, Research Funding. Stilgenbauer:Roche: Consultancy, Honoraria, Research Funding; Mundipharma: Consultancy, Honoraria, Research Funding. Böttcher:Roche: Honoraria, Research Funding, Travel grant Other. Hallek:Roche: Consultancy, Research Funding; Mundipharma: Consultancy, Research Funding.

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