Retrospective analysis of an efficient peripheral blood stem cell collection and the relation between infused cell dose and clinical outcome in patients with malignant lymphoma and multiple myeloma

Introduction: Etoposide (VP16) is a drug used not only for the treatment of lymphoma but also for the collection of peripheral blood stem cells (PBSCs). We analysed the efficacy and adverse effects of collecting PBSCs and the relation between the infused cell dose and the clinical outcome in lymphoid malignancies. Method: Investigating 30 patients with non‐Hodgkin’s lymphoma, one patient with Hodgkin’s lymphoma, and five patients with multiple myeloma, we compared the effects of several doses of etoposide with those of CHOP or CHOP‐like treatments or salvage treatments. We also analysed the relation between the amount of CD34⁺ cells collected (above or below 5.0 × 10⁶/kg/day) and prognosis of these patients. Results: We found the collected cell count to be highest in patients treated with 500 mg/m² of VP16 and lowest in those not treated with VP16 (P = 0.0073). A CD34⁺ cell count above 100/μL on the collection day indicates that the target amount of CD34⁺ cells (4.0 × 10⁶/kg) can be readily obtained and was reached most rapidly by the patients who had received 500 mg/m² of VP16 (P = 0.01). The longer duration of neutropenia in those patients (P = 0.000006) resulted in longer antibiotic treatment (P = 0.0052). Both progression‐free survival (PFS) and overall survival (OS) were better for the patients who yielded more than 5.0 × 10⁶ CD34⁺ cells/kg/day (P = 0.087 for PFS and P < 0.033 for OS). Conclusion: We show here that 3 days of VP16 at 500 mg/m² was useful for the collection of PBSCs and that patients who yielded more than 5.0 × 10⁶ CD34⁺ cells/kg/day survived longer than those who yielded less.