Bosutinib Treatment of Chronic Myeloid Leukemia in Lombardy

Introduction: Up to 30% of CML patients will require a therapeutic change during follow-up due to intolerance and/or resistance to first-line tyrosine kinase inhibitor (TKI) approach. In this context, bosutinib (BOS) has not only demonstrated its efficacy, but also presents a favorable safety profile, without comorbid conditions representing an absolute contraindication to its use. Methods: To gain further into BOS treatment in real life, we conducted a retrospective analysis on the outcome of CML patients receiving BOS in 18 hematological centers, all belonging to the “REL” (Lombard Hematology Network). Results: Of 546 regularly followed CML cases, a total of 132 patients were reported as being treated with BOS, most frequently (62.9%) in second line. Interestingly, most patients (63.6%) switched to BOS due to intolerance to the previous TKI, while resistance to the last treatment was reported in the remaining 36.4% of patients. Despite a permanent discontinuation rate of 18.9%, over 80% of patients achieved at least a major molecular response and seven cases were able to attempt treatment-free remission. Conclusion: Although in this survey BOS represented the preferred option especially in patients intolerant rather than resistant to previous TKIs, we confirmed that BOS represents a safe and effective therapeutic option beyond the first line in the real-life setting.