Peripheral blood progenitor cell collections in multiple myeloma: predictors and management of inadequate collections

Thirty‐seven patients with previously treated multiple myeloma (MM) underwent peripheral blood progenitor cell (PBPC) collection following high‐dose cyclophosphamide and GM‐CSF or sequential IL‐3 and GM‐CSF. Patients with an inadequate collection were considered for a second or third collection. 25 patients underwent subsequent autotransplant. The only variable predictive of CFU‐GM yield was the extent of prior melphalan therapy. All repeat collections were unsuccessful and patients infused with an autograft obtained from multiple sets of collections had a high incidence of delayed engraftment. We conclude that melphalan should be avoided or PBPC collection performed early in the disease course in patients who are potential transplant candidates.