Prof Giuseppe Saglio discusses the use of dasatinib as second line therapy for chronic myeloid leukaemia (CML) patients resistant or intolerant to imatinib. The results of a long term study comparing the use of dasatinib with imatinib were presented at the 2011 EHA meeting in London. These results demonstrated that the optimal dose of dasatinib is 100mg per day; this dosage is associated with a long term cytogenetic response in 50% of patients and dasatinib treatment can be continued for long periods of time without major adverse effects. Prof Saglio talks about the adverse effects experienced by patients, the influence of comorbidities and discusses the other drugs available to patients who are unsuitable for imatinib.