A comparative study of sequential priming and mobilisation of progenitor cells with rhG-CSF alone and high-dose cyclophosphamide plus rhG-CSF

Stem cell mobilisation can be achieved either by administration of rhG-CSF alone or after high-dose cyclophosphamide (HDCy) plus rhG-CSF, We have comp ared both mobilisation procedures intra-individually in 43 patients with ha ematological malignancies, Furthermore, the toxicity data were registered. The CD34(+) cell yield was higher after mobilisation with HDCy plus rhG-CSF than after rhG-CSF alone in 21 out of 22 patients who were actually harves ted after both procedures. If a patient mobilised insufficiently after rhG- CSF alone, the yield of CD34(+) cells after the following HDCy priming was lower compared to patients who mobilised sufficiently after rhG-CSF priming alone, In 12 patients with B cell malignancies a reduced number of B cells such as CD10(+), CD19(+), CD20(+) cells in bone marrow as well as in leuka pheresis products was observed after HDCy plus rhG-CSF compared to rhG-CSF alone. Toxicity data revealed HDCy as a relatively toxic priming regimen wi th all patients hospitalised and 74% experiencing neutropenic fever and adm inistration of intravenous antibiotics. In two patients, seizure-like episo des were observed during cyclophosphamide bolus infusion. In conclusion, HD Cy increased the yield of CD34(+) cell and reduced B cells in leukapheresis products indicating reduced tumour cell load compared with rhG-CSF priming alone, The efficacy of HDCy priming is limited by its profound toxicity an d morbidity, Studies evaluating efficacy and safety of lower doses of cyclo phosphamide are needed.