Molecular Responses At 3 Months Are Associated With a Better Subsequent Molecular response and Outcome In Children and Adolescents With CML In Chronic Phase: Results Of a Retrospective Analysis From The French Glivec Phase 4 Study

Here we report a retrospective analysis based on BCR-ABL transcript level at 3 months after the start of imatinib assessing its impact on subsequent response and outcome in children and adolescents with chronic myeloid leukemia (CML) enrolled in the French prospective trial Glivec Phase 4 (Millot F et al, JCO 2011). Methods 44 children were enrolled in the Glivec Phase 4 Study. The median age was 11.5 years (range: 10 months-17 years). The median follow-up was 49 months (range: 16 to 83). We retrospectively analyzed the rates of complete cytogenetic responses (CCR) and major molecular response (MMR) 1 year after the start of imatinib, the progression free survival (PFS) and the overall survival (OS). Results At 3 months after the start of imatinib, 40/44 (91%) patients were evaluable for molecular response. BCR-ABL transcripts levels were: BCR-ABL> 10% in 15 (37%) pts and BCR-ABL 10% at 3 months had similar Sokal score distribution but a larger spleen size and a higher leukocyte count at diagnosis compared with patients with BCR-ABL 10% and those with 10% (Table 1). However the difference is statistically significant only for the molecular response. Conclusion The children and adolescents with >10% of BCR-ABL at 3 months after the start of imatinib are characterized by a higher propensity to fail the treatment and to progress. The value of a cut-off of 10% of BCR-ABL 3 months after the start of imatinib as a reliable surrogate marker of response at 1 year and outcome remains to be determined in a larger cohort of children and adolescents. Disclosures: No relevant conflicts of interest to declare.