Molecular analysis is recommended for monitoring patients (pts) with CML. For imatinib treated pts in chronic phase (CP), molecular analysis provides important prognostic information. A major molecular response (MMR, BCR-ABL ≤0.1% IS (international scale)) is associated with favourable progression free survival and is a primary endpoint of clinical trials. The 3 month (m) BCR-ABL level is predictive of MMR and almost all de-novo pts with values ≤1.0% IS subsequently achieve MMR. The second generation tyrosine kinase inhibitors nilotinib and dasatinib (2TKI) have demonstrated efficacy for CP pts who fail imatinib therapy due to resistance or intolerance. However, treatment failure associated with the presence of a limited spectrum of resistant mutations is evident. Furthermore, it has recently been suggested that failure to achieve a major cytogenetic response (MCR) by 12m defines inadequate response and these pts should be considered for alternative therapies (
Disclosures: Branford:Bristol Myers Squibb: Honoraria, Research Funding; Novartis: Honoraria, Research Funding. Hughes:Bristol Myers Squibb: Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau.