ELN 2013 response status criteria: relevance for de novo imatinib chronic phase chronic myeloid leukemia patients?

Purpose to evaluate the relevance of the 2013 ELN response status criteria for de novo imatinib (400 mg/d) chronic phase chronic myeloid leukemia (CP-CML) patients. Patients and Methods Response status according to the 2009 and 2013 criteria were determined in 180 unselected patients. Outcome of the subgroups of patients were then compared. Results One hundred and eighty patients were included in this study. The median age at diagnosis was 58.1 years (range, 19.8-88.9) and 112 (62.2%) were male. Sokal risk scores were low in 50 patients (27.7%), intermediate in 74 (41.1%), high in 38 (21.1%) and unknown in 18 patients (10%). Ten patients (5.5%) had clonal evolution at diagnosis. With a median follow up of 5.4 years, the 180 patients were classified as optimal responders (OR2009) (n=113, 62.7%), suboptimal responders (SOR2009) (n=47, 26.1%) and failures (FAIL2009) (n=20, 11.1%) according to the 2009 ELN criteria and optimal responders (OR2013) (n=77, 42.7%), warnings (WAR2013) (n=59, 32.7%) and failures (FAIL2013) (n=44, 24.4%) according to the 2013 ELN criteria. All the patients classified as failures according to the 2009 criteria were classified as failures by the 2013 criteria. Results are presented in table 1. No difference was observed in event-free (EFS), progression-free (PFS) and overall (OS) survivls between OR2009 and SOR2009 or between OR2013 and WAR2013. PFS and OS were not different between SOR2009 and FAIL2009 whereas a significant difference was observed between WAR2013 and FAIL2013 in PFS and OS (p=.003 and p=.024 respectively). No difference in terms of outcome was observed between OR2009 patients who became WAR2013 when compared to OR2013 patients. When compared to FAIL2009 patients, SOR2009 patients who became WAR2013 had better EFS, FFS, PFS and OS. No difference was observed in PFS or OS in SOR2009 patients who became FAIL2013. Conclusion The 2013 ELN response status criteria have improved patients classification in terms of response status. However this improvement is related to a better definition of failure rather than that of optimal response for CP-CML patients treated with IM frontline therapy. Disclosures: Etienne: Ariad Pharmaceuticals: Membership on an entity’s Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; Bristol Myers Squibb: Consultancy, 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. Dulucq:Novartis: Membership on an entity’s Board of Directors or advisory committees. Nicolini:Ariad Pharmaceuticals: 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: Consultancy, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; Teva: Speakers Bureau; Bristol Myers Squibb: Speakers Bureau. Mahon:Novartis: Consultancy, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; Bristol Myers Squibb: Consultancy, 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; Ariad Pharmaceuticals: Membership on an entity’s Board of Directors or advisory committees.