Imatinib-associated neutropenia may not be overcome by filgrastim treatment in patients with blastic phase of chronic myeloid leukaemia.

Imatinib mesylate is a very effective treatment in patients with Philadelphia (Ph)-positive chronic myeloid leukaemia (CML). However, in patients with advanced phase CML, it is still unclear whether, in the presence of myelosuppression, therapy with imatinib should be continued. It has been reported that intermittent filgrastim treatment may overcome imatinib-associated neutropenia and allow improved delivery of imatinib. Such combined sequential treatment is theoretically attractive as it may lead to better disease response. Here, we report a patient with blastic phase CML who developed severe and prolonged myelosuppression during imatinib treatment. Despite cessation of imatinib and 2 months of filgrastim therapy neither recurrence of Ph-positive or Ph-negative cells occurred. We conclude that filgrastim treatment may not always reverse imatinib-associated neutropenia therefore the decision of continued imatinib therapy in patients with advanced CML should be taken with caution.