Intermediate-dose CY and G-CSF more efficiently mobilize adequate numbers of PBSC for tandem autologous PBSC transplantation compared with low-dose CY in patients with multiple myeloma

BackgroundAutologous PBSC transplantation is the standard care for patients with multiple myeloma. The most common regimen used to mobilize PBSC consists of CY and G-CSF.MethodsWe retrospectively analyzed the efficacy and toxicity of two regimens of CY for PBSC mobilization: low-dose CY (1–2 g/m2, LD-CY, n = 61) plus G-CSF, and intermediate-dose CY (3–4 g/m2, ID-CY, n = 26) plus G-CSF.ResultsIn the LD-CY group, 5.17 (0.23–17.3)×106 CD34+ cells/kg, and in the ID-CY group 7.71 (0.08–26.4)×106 CD34+ cells/kg (P = 0.018), were collected. Although ≥2 × 106/kg CD34+ cells were collected in 89% of the LD-CY group and 92% of the ID-CY group, this was achieved after a single leukapheresis in 54% of the LD-CY group and 92% of the ID-CY group (P = 0.0001). Patients who are to have tandem autologous PBSC transplants require ≥4 × 106/kg CD34+ cells. This was achieved in only 65% patients in the LD-CY group but 88% in the ID-CY group (P = 0.05). Among patients who had not had prior melphalan and/or >12 months of prior treatment, 74% in the LD-CY group and 100% in ID-CY group mobilized ≥4x106/kg CD34+ cells. Febrile neutropenia was more frequent in the ID-CY group (38% vs. 13%).DiscussionIn conclusion, compared with LD-CY, patients receiving ID-CY were more likely to collect a total CD34+ cell number adequate for tandem autologous PBSC transplantation. The increased toxicity was manageable and considered acceptable.