Randomised comparison of two B-cell purging protocols for patients with B-cell non-Hodgkin lymphoma: in vivo purging with rituximab versus ex vivo purging with CliniMACS CD34 +

Summary We investigated the feasibility, safety and efficacy of two B-cell purging methods in patients with CD20 + non-Hodgkin lymphoma (NHL) receiving autologous stem cell transplantation. Myeloid and immune recoveries between the methods were compared. Twenty-seven patients were randomised to either in vivo purging with rituximab or ex vivo purging by CD34 + cell selection. Both purging methods were efficient at eliminating B-cells in infusates. When compared with in vivo purging, ex vivo purging was associated with CD34 + cell loss and delayed median neutrophil (10 d vs. 11 d) and platelet (12AE5 d vs. 17 d) count recoveries. Lymphocyte recovery was similar in both groups, but immunoglobulin recovery was delayed after in vivo purging. Late-infectious complications were few in both arms. At a median follow-up of 27 months, 2-year probabilities of event-free survival (EFS) rates were 81% for in vivo purging and 76% for ex vivo purging (P ¼ 0AE66). When compared with 53 unpurged patients, all 27 purged patients had improved 3-year probabilities of overall survival (89% vs. 70%, P ¼ 0AE014) and a trend for improved EFS (78% vs. 57%, P ¼ 0AE075). In conclusion, although both purging methods were feasible and safe, rituximab purging was superior as it did not impair CD34 + cell mobilisation and was