Chemotherapy for mobilisation of Ph-negative progenitor cells from patients with CML: impact of different mobilisation regimens

Mobilised peripheral blood stem cells are widely used for autografting in p atients with chronic myeloid leukaemia (CML) and it is generally thought th at a high proportion of Ph-negative progenitor cells in the graft is desira ble, We report here the results of 91 stem cell mobilisations performed wit h various chemotherapy regimens followed by G-CSF, We show that mobilisatio n of Ph-negative cells is possible after diagnosis as well as in advanced s tages of the disease, The yield of Ph-negative cells is highly dependent on the chemotherapy regimen: while the combination of idarubicin and cytarabi n for 3-5 days (IC3-5) mobilised Ph-negative cells in most patients, high-d ose cyclophosphamide was ineffective. Mobilisation of Ph-negative progenito r cells after IC3 was at least as effective as after IC5; however, less aph eresis sessions were required, and toxicity was much reduced after IC3. Com pared to historical controls, IC was equally effective as the widely used I CE/minilCE (idarubicin, cytarabin, etoposide) protocol. No correlation was found between graft quality and the cytogenetic response to subsequent trea tment with interferon-alpha. We conclude that IC3 is an effective and well- tolerated regimen for mobilising Ph-negative cells that compares well with more aggressive approaches such as IC5 and ICE/minilCE.