Peripheral blood stem cell transplantation in myeloma using CD34 selected cells

We have performed nine CD34 selection procedures on peripheral blood stem cells harvested from eight patients with myeloma using the Cellpro avidin-biotin immunoaffinity column (Ceprate). They all received CVAMP chemotherapy to maximum response prior to mobilisation. Six of the patients have been transplanted using these cells, one receiving successive autografts. Median absolute cell numbers processed and retrieved were : 31.1 x 10 9 pre-column, 2.07 x 10 8 in the final product and 30.4 x 10 9 in the column waste. Mean CD34 positivity in the product was 49% (range 18.4-98) with a median CD34 + yield of 31.4% (range 21-37.8). IgH PCR was performed and seven of the eight patients were amplifiable. Of these, two were positive in the precolumn product and both of these were successfully purged with a negative result in the final, post-column product. Patients were transplanted with a median of 2.0 x 10 6 CD34 + cells/kg (range 1.5-9.4) following conditioning with melphalan 200 mg/m 2 . The mean time to recovery of neutrophils to >0.5 x10 9 /l and platelets to >20 x 10 9 /l was 16 and 17 days, respectively. At a mean follow-up of 9 months, four of the six patients transplanted are alive, three of them in complete remission and one in a clinically stable relapse. One has died of disease relapse and one of progressive neurological problems the aetiology of which was uncertain but there was no sign of progression of their myeloma. We conclude that PBSCT using CD34 selected cells is safe and practical in myeloma following remission induction with CVAMP chemotherapy.