First-Line Second Generation Tyrosine Kinase Inhibitors in Newly Diagnosed Accelerated Phase Chronic Myeloid Leukemia Patients.

Introduction Up to 10% of patients (pts) with chronic myeloid leukemia (CML) are already in accelerated phase (AP) at diagnosis and despite treatment advances in the field of tyrosine kinase inhibitors (TKIs), management of these pts is challenging. This study aims to examine the benefit of second generation BCR-ABL tyrosine kinase inhibitors (TKI2) as first-line treatment for newly diagnosed AP-CML. Methods Pts meeting criteria for AP-CML at diagnosis and treated with first-line TKI2 (i. e. Nilotinib or Dasatinib) were included in this retrospective multicenter observational national study. AP-CML were defined according to the ELN (Baccarani, Blood 2013) as hematological acceleration (HEM-AP, any of the following features: blasts in PB or marrow 15-29%, or blasts+promyelocytes in PB or marrow >30% with blasts Results Sixty-six pts were analysed: 45 males (68%) and 21 females (32%) with a median age at diagnosis of 49 (15-78.5) years. The median follow-up of the cohort was 43.5 (1.7-117) months. We segregated the pts in HEM-AP (n=33) and ACA-AP (n=33) for further analyses. Nine pts with HEM-AP harboured ACA and were analysed in the HEM-AP group. Fusion transcripts were of the Major BCR in 57 pts, 6 pts had atypical BCR-ABL transcripts (2 e19a2, and 1 e1a2 in the HEM-AP group and 2 e19a2 and 1 Ma3 in the ACA-AP group), and 3 transcripts unknown. Not surprisingly, spleen enlargement was significantly greater in the HEM-AP group [10 (5-14.75) vs. 3 (0-10)cm, p=0.014]. PB basophils [median 10 (6-16) vs. 3 (2-5)%, p Treatment responses did not significantly differ between ACA-AP and HEM-AP group, regardless of the TKI2 administered, with 33/33 (100%) vs 31/33 (94%) pts achieving a CHR, 2/33 (6%) pts vs 0/33 (0%) pts achieving a MCyR, 5/33 (15%) pts vs 5/33 (15%) pts achieving CCyR, 9/33 (27%) pts vs 4/33 (12%) pts achieving a MMR respectively. However, 11/33 (33%) HEM-AP vs 22/33 (66%) ACA-AP pts achieved a deep molecular response (p=0.013, Fisher test). Median times to CHR and MMR were not significantly different between ACA-AP group and HEM-AP group with 1.05 vs 1.25 months (p=0.088) for CHR and 6 vs 7 months (p=0.156) for MMR, respectively. Overall, the estimated 7-yr FFS rate was 56.92% (95%CI: 40-81), 7-yr PFS was 83.42% (95% CI: 69.6-100%) and 7-yr OS was 87.14% (95%CI: 73.5-100%) (Figure 1.) with no significant differences between ACA-AP vs HEM-AP pts [7-yr FFS: 57.7 vs. 62%, p=0.739; 7-yr PFS: 84.7% vs. 84%, p=0.185; 7-yr OS: 88.9% vs 86.6%, p=0.132] respectively. There was also no difference in FFS, PFS and OS according to the type of TKI2. The only factors influencing negatively OS were the % of BM blasts (HR=1.17, 95%CI: 1.1-1.28, p Conclusion The initiation of a TKI2 in newly diagnosed AP-CML pts induces excellent response and survival rates, probably superior to that of Imatinib first-line, and counterbalances the negative impact of this advanced disease, particularly in HEM AP subgroup. Disclosures Etienne:Pfizer: Membership on an entity9s Board of Directors or advisory committees, Other: Travel, Speakers Bureau; BMS: Membership on an entity9s Board of Directors or advisory committees, Other: Travel, Speakers Bureau; Novartis: Membership on an entity9s Board of Directors or advisory committees, Speakers Bureau; Incyte: Honoraria, Patents & Royalties, Speakers Bureau. Berger:Sanofi: Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding. Mahon:Incyte: Speakers Bureau; Pfizer: Speakers Bureau; Novartis: Speakers Bureau; BMS: Speakers Bureau. Rea:Bristol-Myers Squibb: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Incyte: Honoraria; Pfizer: Honoraria. Nicolini:BMS: Consultancy, Speakers Bureau; Incyte Biosciences: Consultancy, Speakers Bureau; Sun Pharma Ltd: Consultancy.