Difficult stem cell mobilization despite adequate CD34⁺ cell dose predicts shortened progression free and overall survival after autologous HSCT for lymphoma

Hematopoietic growth factors alone or in combination with myelosuppressive chemotherapy are used to mobilize peripheral blood stem cells for autologous transplantation. To identify characteristics of successful mobilization with granulocyte colony-stimulating factor (G-CSF) alone and to study the impact of immediate chemotherapy mobilization following G-CSF mobilization, we treated 175 chemotherapy sensitive lymphoma patients with G-CSF (G) mobilization and leukapheresis followed by chemotherapy plus G-CSF (CG) mobilization and leukapheresis and then autologous transplantation. Patients with stage I/II disease at diagnosis and ≤5 years from diagnosis were more likely to mobilize successfully with G-CSF alone (G). CG mobilization led to superior stem cell yields compared to the preceding mobilization with G (median 2.37 vs 1.37 (×10⁶CD34⁺ cells/kg); P<0.0001). Patients (n = 58, 33%) with successful G-CSF mobilization (≥2 × 10⁶ CD34⁺ cells/kg) had quicker platelet recovery and improved progression free and overall survival compared to patients who had adequate collection only after chemotherapy mobilization or to those who failed to collect an adequate graft with either type of mobilization. The poor clinical outcome of patients with difficult mobilization using either method identifies them as a high-risk group who might benefit from alternative therapies.