The Role of Early Molecular Response in the Management of Chronic Phase CML

PURPOSE OF REVIEW: Although tyrosine kinase inhibitors (TKIs) spectacularly improve the disease burden and the overall survival of chronic myeloid leukemia patients, early identification of a subset of poor TKI responders has been recognized as a critical goal to prevent disease progression in these patients. We herein review the past and recent evidence on the impact of early response. RECENT FINDINGS: In the recent years, the achievement of an early molecular response (EMR, defined as 3-month BCR-ABL1 transcript <10% IS) has emerged as a useful tool to identify poor-risk patients. Although several groups have reported the importance of such milestone, clinical intervention based on it remains controversial partly due to its low specificity to predict progression, which may be partially improved by using the rate of decline in BCR-ABL1 transcript level (halving time or velocity of ratio reduction). SUMMARY: Standardization of halving time or velocity of ratio reduction will likely help establishing more stringent recommendation and modify current clinical practices.